IT'S "THAT GODDAMN PARTICLE"
10 years after the discovery of the Higgs boson, physicists still can't get enough of the 'God particle'


By Keith Cooper published about 16 hours ago

"Particle physics has changed more in the past 10 years than in the previous 30 years."

An artist's depiction of a Higgs boson. (Image credit: Tobias Roetsch/Future Publishing via Getty Images)

Ten years ago, jubilant physicists working on the world's most powerful science experiment, the Large Hadron Collider (LHC) at CERN, announced the discovery of the Higgs boson — a particle that scientists had been searching for since 1964, when its existence was first predicted.

"For particle physicists, the Higgs boson was the missing piece of the Standard Model," Victoria Martin, a professor of particle physics at the University of Edinburgh in the U.K., told Space.com.

Although the Large Hadron Collider's remit is wide-ranging, searching for the Higgs boson was its top priority when it came online in 2010. The LHC's two key experiments — ATLAS (A Toroidal LHC Apparatus) and CMS (Compact Muon Solenoid) — detected the Higgs boson within just two years of beginning operations.

"We were not expecting to see the Higgs boson so quickly," CERN's Director-General, Fabiola Gianotti, said during a preview press conference held on Thursday (June 30). It was the LHC's superior computing infrastructure applied to experiments that performed better than their design specifications — testament to the many years of hard work put into building the LHC — that accelerated the Higgs boson's discovery, she said.


Related: 10 cosmic mysteries the Large Hadron Collider could unravel

Read more: Our original coverage of the Higgs discovery

The mystery of mass

The Higgs boson changed the world of particle physics, opening doors that had been slammed shut until its discovery.

"Particle physics has changed more in the past 10 years than in the previous 30 years," Gian Giudice, head of CERN's theoretical physics department, said during the event.

The Higgs boson is important because it carries the force of an energy field known as the Higgs field, in much the same way that a photon carries the force of the electromagnetic field.

"The field is more fundamental than the particles," Martin said. "It permeates all the way across space and time." It's the interaction between certain particles and the Higgs boson, which represents the Higgs field, that gives those particles their mass.

"Particle physics has changed more in the past 10 years than in the previous 30 years."— Gian Giudice

One analogy is to think of the Higgs field as a kind of cosmic treacle that slows down some particles more than others. Less massive particles pass through the Higgs field relatively effortlessly, and so they can fly off at the speed of light — think of electrons, which have a tiny mass, or photons, which have no mass at all. For other particles, wading through the cosmic treacle of the Higgs field slows them down, giving them more mass, and therefore these particles are the most massive.

Just like these particles, scientists believe — although they have yet to watch the process happen — that the Higgs boson also gets its mass from interacting with itself. And measurements by the LHC have shown that the Higgs boson has a high mass as well: 125 billion electronvolts, which is about 125 times more massive than one of the positively charged protons at an atom's core. (Thanks to Einstein's special relativity, particle physicists know that mass and energy are interchangeable and so refer to masses in terms of their energy.) Only one fundamental particle known to science is more massive.

Discovering the Higgs boson and measuring its mass was only the beginning. "We've spent the last 10 years testing the Higgs boson, because discovering it was one thing, but the Standard Model also tells us lots of things about the way the Higgs boson should behave," Martin said.



The ATLAS instrument at the Large Hadron Collider.

 (Image credit: CERN/Claudia Marcelloni/Max Brice)

An existential question


For one thing, the Higgs boson's quantum spin — or lack thereof — could provide an insight into why our universe even exists.

Every known particle has a quantum spin, except for the Higgs boson. The Standard Model of particle physics predicted this oddity, so it isn't a surprise, but scientists including Martin and her research team have continued trying to measure the spin of the Higgs boson as a way to test the Standard Model. So far, they've found no evidence that it has any spin.

The reason why the Higgs boson has no spin when every other known particle does is because of the nature of the Higgs field. Unlike the gravitational and electromagnetic fields, which have obvious sources such as an object's mass or an electric current passing through magnetic fields, the Higgs field has no source. It's just there, a non-localized part of the cosmos pervading everything. As such it is coupled to the 'vacuum,' the very fabric of space-time, and therefore the field shares the vacuum's properties. The vacuum has no quantum spin, and therefore neither does the Higgs boson.

However, the vacuum isn't inert. Particles fizz in and out of existence thanks to quantum fluctuations, raising the energy level of the vacuum above its lowest possible state. The thing about energy levels is that an object — be it a person in a gravitational field, an electron orbiting an atomic nucleus, or the vacuum — always prefers to be at its lowest possible energy level. Yet our universe is not. What keeps the universe from succumbing to the inevitable urge to drop energy levels is the shape of what scientists characterize as the energy potential of the Higgs field.

A graph of this energy potential would look like a 'mountain' in the middle, and two 'valleys' flanked by 'hills' on either side. The energy level of the vacuum would lie in one of those valleys, but physicists strongly suspect that on either side of those hills are even deeper 'valleys' representing even lower energy states. And the measurement of the mass of the Higgs boson supports this idea; the particle is so large that it suggests that there's room for the Higgs field to potentially decay to a lower energy level one day.

"The Higgs boson is a very precise microscope to study nature at the smallest scales, and at the same time it is a formidable telescope to access physics at very high energy scales."— Fabiola Gianotti

For this reason, physicists call our vacuum a 'false' vacuum, because it 'wants' to decay to a lower energy — a 'truer' vacuum. The valleys and hills of the Higgs field's energy potential are holding our universe in this false vacuum, long enough for planets, stars and galaxies to form.

However, over eons upon eons of time, the false vacuum is inherently unstable, and eventually it will decay. Maybe quantum energy fluctuations will allow the false vacuum to climb over those 'hills' and roll down the slope on the other side, or maybe the strange phenomenon of quantum tunneling will let it drill through the 'hill' that is the energy barrier.

However it happens, it would be bad for the universe — the decay of the false vacuum would expand outward in a wave moving at the speed of light, destroying everything and replacing it all with a true vacuum. It's only the Higgs field that is holding vacuum decay at bay, so we therefore have the Higgs field to thank for our current universe

A schematic of one of the proton-proton collisions at the LHC that revealed the Higgs boson decaying into daughter particles.

 (Image credit: CERN/CMS Collaboration/Thomas McCauley/Lucas Taylor)

Another run at understanding the universe

In addition to the Higgs boson's spin, researchers have spent the past decade trying to pin down its life span. The Higgs boson existence is fleeting; the standard model predicts that a Higgs boson survives for a tiny amount of time, just 10^–22 seconds, before breaking apart into more subatomic particles. However, this calculation hasn't been experimentally verified yet. "It happens so quickly," Martin said.

THEY ARE ABOUT TO CHANGE QUANTUM REALITY, AGAIN
Physicists hope that the next operational phase on the LHC, dubbed Run 3 and beginning on Tuesday (July 5), will serve as the much sought-after stopwatch.

"We hope that in an indirect way we might be able to make a measurement of how long the Higgs boson is living for," Martin said. "If we can measure the lifetime it will give us more constraints on what particles the Higgs boson is decaying into."

In turn, understanding how the Higgs boson breaks apart into other particles could reveal hidden subatomic particles new to science, perhaps even including particles of mysterious dark matter.

Because of these implications, Gianotti described the Higgs boson as a crucial tool for probing the deepest mysteries of particle physics. "The Higgs boson is a very precise microscope to study nature at the smallest scales, and at the same time it is a formidable telescope to access physics at very high energy scales," she said.

The discovery of the Higgs boson hasn't just allowed physicists to tick another particle off the list. Its very existence and its behavior raise questions about some of the most profound areas of fundamental physics: the structure of matter in the universe, the fate of the universe, whether the universe is stable, and how elementary particles relate to each other.

RELATED STORIES:
— Higgs boson: The 'God Particle' explained
— The Large Hadron Collider: Inside CERN's atom smasher
— The Higgs boson could have kept our universe from collapsing

However, the Higgs boson continues to play coy with its secrets. "Everything that we've seen so far seems to be just what the Standard Model predicted," Martin said. "While this is interesting, it is also slightly disappointing because we were hoping that the Higgs boson might help us see beyond the Standard Model."

Far from breaking the rules and destroying physics, moving beyond the Standard Model is necessary to explain phenomena that doesn't fit, such as dark matter, or opening doorways into new physics, such as supersymmetry. It's why, fresh off four years of upgrades, the LHC will once again tackle the mysteries of the Higgs boson.


Follow Keith Cooper on Twitter @21stCenturySETI. Follow us on Twitter @Spacedotcom and on Facebook.
Keith Cooper (opens in new tab)

Contributing writer
Keith Cooper is a freelance science journalist and editor in the United Kingdom, and has a degree in physics and astrophysics from the University of Manchester. He's the author of "The Contact Paradox: Challenging Our Assumptions in the Search for Extraterrestrial Intelligence" (Bloomsbury Sigma, 2020) and has written articles on astronomy, space, physics and astrobiology for a multitude of magazines and websites.

Particle physics: A decade of Higgs boson research

Nature

July 4, 2022

Ten years after the first reported observation of the Higgs boson at the CERN Large Hadron Collider, the most up-to-date results of the properties of this elementary particle from the ATLAS and CMS collaborations are presented in two papers published Nature.

In July 2012, the ATLAS and CMS collaborations announced that they had found a particle with properties that matched those expected for the Higgs boson. Since then, more than 30 times as many Higgs bosons have been detected, offering the opportunity to verify if its behaviour matches up with the standard model of elementary particle physics.

The two collaborations present an analysis of data produced within Run 2 of the Large Hadron Collider (between 2015 and 2018) that involve production or decay of Higgs bosons. The key question investigated by the researchers is how the Higgs boson interacts with other elementary particles. According to the theory from the standard model of particle physics, the strength with which any particle interacts with the Higgs boson should be proportional to the particle mass. Ten years of data allow the two collaborations to estimate, within reasonable errors, the Higgs interaction with the heaviest known particles: top and bottom quarks, Z and W bosons and tau lepton. For all these particles the data fall precisely in line, within experimental errors, of the behaviour predicted by the standard model of elementary particle physics.

The progress made over the past decade is predicted to continue over the next one. Some of the key properties of the Higgs boson, such as coupling to itself or to lighter particles, remain to be measured and potentially reveal deviations from theory. However, the current dataset is expected to more than double during the next decade of research, which will help to improve our understanding of Higgs boson physics.

The progress made in the past decade, what remains to be established, and potential future explorations are discussed in a Perspective by Giulia Zanderighi and colleagues.

doi:10.1038/s41586-022-04893-w

SEE LA REVUE GAUCHE - Left Comment: Search results for HIGGS BOSON 

THAT GOD(DAMN) PARTICLE

ATLAS and CMS Collaborations Find First Evidence of Rare Higgs Boson Decay

ATLAS and CMS combined their datasets from the second run of the LHC

ByAditya Saikrishna
May 27, 2023

Photo Credit: Twitter/CMSExperiment

SWITZERLAND: Scientists at CERN’s Large Hadron Collider (LHC) have achieved another breakthrough in particle physics as the ATLAS and CMS collaborations joined forces to provide the first evidence of the Higgs boson decaying into a Z boson and a photon.

This rare decay process could shed light on particles beyond the Standard Model and deepen our understanding of the nature of the Higgs boson.

The discovery of the Higgs boson in 2012 opened new avenues for research in particle physics. Since then, scientists have meticulously explored its properties and investigated its various decay processes.

At the recent Large Hadron Collider Physics conference, ATLAS and CMS presented their joint efforts to uncover the elusive decay of the Higgs boson into a Z boson and a photon.- Advertisement -

The decay of the Higgs boson into a Z boson and a photon resembles a degeneration into two photons. However, these decays do not occur directly but involve an intermediate “loop” of “virtual” particles that researchers cannot observe directly.

These virtual particles could include yet undiscovered particles that interact with the Higgs boson, potentially challenging the predictions of the Standard Model.

According to the Standard Model, around 0.15% of Higgs bosons with a mass of approximately 125 billion electronvolts should decay into a Z boson and a photon

However, theories extending beyond the Standard Model propose different decay rates. Scientists gain valuable insights into physics beyond the Standard Model and the characteristics of the Higgs boson itself by measuring the decay rate.

Previously, both ATLAS and CMS independently conducted extensive searches for the Higgs boson decay using data from proton-proton collisions at the LHC.

Employing similar strategies, they identified the Z boson through its decay into pairs of electrons or muons, heavier counterparts of electrons. The team found these Z boson decays in approximately 6.6% of the cases.

In their searches, ATLAS and CMS looked for collision events associated with the Higgs boson decay, represented by a narrow peak in the combined mass distribution of the decay products against a smooth background.

The collaborations categorized events based on the characteristics of the Higgs boson’s production processes and implemented advanced machine-learning techniques to distinguish between signal and background events.

In a new study, ATLAS and CMS combined their datasets from the second run of the LHC (2015-2018) to maximize the statistical precision of their search.

The collaboration resulted in the first evidence of the Higgs boson decaying into a Z boson and a photon, with a statistical significance of 3.4 standard deviations.

While the standard deviation falls short of the conventional requirement of 5 standard deviations for claiming an observation, the measured signal rate is 1.9 standard deviations above the Standard Model prediction.

Pamela Ferrari, an ATLAS physics coordinator, emphasized the significance of rare Higgs decays, stating that each particle has a unique relationship with the Higgs boson and searching for it is a high priority.

Florencia Canelli, a CMS physics coordinator, highlighted the potential implications of new particles on rare Higgs decay modes and expressed optimism about future advancements using the ongoing third run of the LHC and the forthcoming High-Luminosity LHC.

This collaborative effort by ATLAS and CMS brings us one step closer to unravelling the mysteries surrounding the Higgs boson and provides an insightful test of the Standard Model.

With further advancements and precision expected in future experiments, scientists anticipate probing even rarer Higgs decays, potentially uncovering new particles and revolutionizing our understanding of the universe’s fundamental building blocks.

If the Higgs can reach the Hidden Valley, we will see new physics already in next-generation accelerators

Peer-Reviewed Publication

THE HENRYK NIEWODNICZANSKI INSTITUTE OF NUCLEAR PHYSICS POLISH ACADEMY OF SCIENCES

 

IMAGE: THE SEARCH FOR EXOTIC HIGGS BOSON DECAYS IN FUTURE LEPTON COLLIDERS: 1) AN ELECTRON AND A POSITRON FROM OPPOSING BEAMS COLLIDE; 2) THE COLLISION PRODUCES A HIGH-ENERGY HIGGS BOSON; 3) THE BOSON DECAYS INTO TWO EXOTIC PARTICLES MOVING AWAY FROM THE AXIS OF THE BEAMS; 4) EXOTIC PARTICLES DECAY INTO PAIRS OF QUARK-ANTIQUARK, VISIBLE TO DETECTORS. view more 

CREDIT: SOURCE: IFJ PAN

It may be that the famous Higgs boson, co-responsible for the existence of masses of elementary particles, also interacts with the world of the new physics that has been sought for decades. If this were indeed to be the case, the Higgs should decay in a characteristic way, involving exotic particles. At the Institute of Nuclear Physics of the Polish Academy of Sciences in Cracow, it has been shown that if such decays do indeed occur, they will be observable in successors to the LHC currently being designed.

When talking about the 'hidden valley', our first thoughts are of dragons rather than sound science. However, in high-energy physics, this picturesque name is given to certain models that extend the set of currently known elementary particles. In these so-called Hidden Valley models, the particles of our world as described by the Standard Model belong to the low-energy group, while exotic particles are hidden in the high-energy region. Theoretical considerations suggest then the exotic decay of the famous Higgs boson, something that has not been observed at the LHC accelerator despite many years of searching. However, scientists at the Institute of Nuclear Physics of the Polish Academy of Sciences (IFJ PAN) in Cracow argue that Higgs decays into exotic particles should already be perfectly observable in accelerators that are successors to the Large Hadron Collider – if the Hidden Valley models turn out to be consistent with reality.

“In Hidden Valley models we have two groups of particles separated by an energy barrier. The theory is that there could then be exotic massive particles which could cross this barrier under specific circumstances. The particles like Higgs boson or hypothetic Z’ boson would act as communicators between the particles of both worlds. The Higgs boson, one of the most massive particle of the Standard Model, is a very good candidate for such a communicator,” explains Prof. Marcin Kucharczyk (IFJ PAN), lead author of an article in the Journal of High Energy Physics, which presents the latest analyses and simulations concerning the possibility of detecting Higgs boson decays in the future lepton accelerators.

The communicator, after passing into the low energy region, would decay into two rather massive exotic particles. Each of these would, in picoseconds – that is, trillionths of a second – decay into another two particles, with even smaller masses, which would then be within the Standard Model. So what signs would be expected in the detectors of future accelerators? The Higgs itself would remain unnoticed, as would the two Hidden Valley particles. However, the exotic particles would gradually diverge and eventually decay, generally into quark-antiquark beauty pairs visible in modern detectors as jets of particles shifted from the axis of the lepton beam 

“Observations of Higgs boson decays would therefore consist of searching for the jets of particles produced by quark-antiquark pairs. Their tracks would then have to be retrospectively reconstructed to find the places where exotic particles are likely to have decayed. These places, professionally called decay vertices, should appear in pairs and be characteristically shifted with respect to the axis of the colliding beams in the accelerator. The size of these shifts depends, among other things, on masses and average lifetime of exotic particles appearing during the Higgs decay”, says Mateusz Goncerz, M.Sc. (IFJ PAN), co-author of the paper in question.

The collision energy of protons at the LHC, currently the world's largest particle accelerator, is up to several teraelectronvolts and is theoretically sufficient to produce Higgs capable of crossing the energy barrier that separates our world from the Hidden Valley. Unfortunately, protons are not elementary particles – they are composed of three valence quarks bound by strong interactions, capable of generating huge numbers of constantly appearing and disappearing virtual particles, including quark-antiquark pairs. Such a dynamic and complex internal structure produces huge numbers of secondary particles in proton collisions, including many quarks and antiquarks with large masses. They form a background in which it becomes practically impossible to find the particles from the exotic Higgs boson decays that are being sought.

The detection of possible Higgs decays to these states should be radically improved by accelerators being designed as successors to the LHC: the CLIC (Compact Linear Collider) and the FCC (Future Circular Collider). In both devices it will be possible to collide electrons with their anti-material partners, the positrons (with CLIC dedicated to this type of collision, while FCC will also allow collisions of protons and heavy ions). Electrons and positrons are devoid of internal structure, so the background for exotic Higgs boson decays should be weaker than at the LHC. Only will it be sufficiently so to discern the valuable signal?

In their research, physicists from the IFJ PAN took into account the most important parameters of the CLIC and FCC accelerators and determined the probability of exotic Higgs decays with final states in the form of four beauty quarks and antiquarks. To ensure that the predictions cover a wider group of models, the masses and mean lifetimes of the exotic particles were considered over suitably wide ranges of values. The conclusions are surprisingly positive: all indications are that, in future electron-positron colliders, the background of exotic Higgs decays could be reduced even radically, by several orders of magnitude, and in some cases could even be considered negligible.

The existence of particle-communicators is not only possible in Hidden Valley models, but also in other extensions of the Standard Model. So if the detectors of future accelerators register a signature corresponding to the Higgs decays analysed by the Cracow researchers, this will only be the first step on the road to understanding new physics. The next will be to collect a sufficiently large number of events and determine the main decay parameters that can be compared with the predictions of theoretical models of the new physics.

“The main conclusion of our work is therefore purely practical. We are not sure whether the new physics particles involved in Higgs boson decays will belong to the Hidden Valley model we used. However, we have treated this model as representative of many other proposals for new physics and have shown that if, as predicted by the model, the Higgs bosons decay into exotic particles, this phenomenon should be perfectly visible in those electron and positron colliders which are planned to be launched in the near future”, concludes Prof. Kucharczyk.

The research in question was funded by an OPUS grant from the Polish National Science Centre.

The Henryk Niewodniczański Institute of Nuclear Physics (IFJ PAN) is currently one of the largest research institutes of the Polish Academy of Sciences. A wide range of research carried out at IFJ PAN covers basic and applied studies, from particle physics and astrophysics, through hadron physics, high-, medium-, and low-energy nuclear physics, condensed matter physics (including materials engineering), to various applications of nuclear physics in interdisciplinary research, covering medical physics, dosimetry, radiation and environmental biology, environmental protection, and other related disciplines. The average yearly publication output of IFJ PAN includes over 600 scientific papers in high-impact international journals. Each year the Institute hosts about 20 international and national scientific conferences. One of the most important facilities of the Institute is the Cyclotron Centre Bronowice (CCB), which is an infrastructure unique in Central Europe, serving as a clinical and research centre in the field of medical and nuclear physics. In addition, IFJ PAN runs four accredited research and measurement laboratories. IFJ PAN is a member of the Marian Smoluchowski Kraków Research Consortium: "Matter-Energy-Future", which in the years 2012-2017 enjoyed the status of the Leading National Research Centre (KNOW) in physics. In 2017, the European Commission granted the Institute the HR Excellence in Research award. As a result of the categorization of the Ministry of Education and Science, the Institute has been classified into the A+ category (the highest scientific category in Poland) in the field of physical sciences.

SCIENTIFIC PUBLICATIONS:

“Search for exotic decays of the Higgs boson into long-lived particles with jet pairs in the final state at CLIC”

M. Kucharczyk, M. Goncerz

Journal of High Energy Physics, 131, 2023

DOI: https://doi.org/10.1007/JHEP03(2023)131

LINKS:

http://www.ifj.edu.pl/

The website of the Institute of Nuclear Physics, Polish Academy of Sciences.

http://press.ifj.edu.pl/

Press releases of the Institute of Nuclear Physics, Polish Academy of Sciences.

IMAGES:

IFJ230518b_fot01s.jpg                                 

HR: http://press.ifj.edu.pl/news/2023/05/18/IFJ230518b_fot01.jpg

The search for exotic Higgs boson decays in future lepton colliders: 1) an electron and a positron from opposing beams collide; 2) the collision produces a high-energy Higgs boson; 3) the boson decays into two exotic particles moving away from the axis of the beams; 3) exotic particles decay into pairs of quark-antiquark, visible to detectors. (Source: IFJ PAN)

---

JOURNAL

Journal of High Energy Physics

DOI

10.1007/JHEP03(2023)131 

ARTICLE TITLE

Search for exotic decays of the Higgs boson into long-lived particles with jet pairs in the final state at CLIC

ARTICLE PUBLICATION DATE

17-Mar-2023

Demystifying vortex rings in nuclear fusion, supernovae

A mathematical model linking these vortices with more pedestrian types, like smoke rings, could help engineers control their behavior in power generation and more

Peer-Reviewed Publication

UNIVERSITY OF MICHIGAN

Images

Better understanding the formation of swirling, ring-shaped disturbances—known as vortex rings—could help nuclear fusion researchers compress fuel more efficiently, bringing it closer to becoming a viable energy source. 

The model developed by researchers at the University of Michigan could aid in the design of the fuel capsule, minimizing the energy lost while trying to ignite the reaction that makes stars shine. In addition, the model could help other engineers who must manage the mixing of fluids after a shock wave passes through, such as those designing supersonic jet engines, as well as physicists trying to understand supernovae.

"These vortex rings move outward from the collapsing star, populating the universe with the materials that will eventually become nebulae, planets and even new stars—and inward during fusion implosions, disrupting the stability of the burning fusion fuel and reducing the efficiency of the reaction," said Michael Wadas, a doctoral candidate in mechanical engineering at U-M and corresponding author of the study.

"Our research, which elucidates how such vortex rings form, can help scientists understand some of the most extreme events in the universe and bring humanity one step closer to capturing the power of nuclear fusion as an energy source," he said.

Nuclear fusion pushes atoms together until they merge. This process releases several times more energy than breaking atoms apart, or fission, which powers today's nuclear plants. Researchers can create this reaction, merging forms of hydrogen into helium, but at present, much of the energy used in the process is wasted.

Part of the problem is that the fuel can't be neatly compressed. Instabilities cause the formation of jets that penetrate into the hotspot, and the fuel spurts out between them—Wadas compared it to trying to squish an orange with your hands, how juice would leak out between your fingers. 

Vortex rings that form at the leading edge of these jets, the researchers have shown, are mathematically similar to smoke rings, the eddies behind jellyfish and the plasma rings that fly off the surface of a supernova.

Perhaps the most famous approach to fusion is a spherical array of lasers all pointing toward a spherical capsule of fuel. This is how experiments are set up at the National Ignition Facility, which has repeatedly broken records for energy output in recent years. 

The energy from the lasers vaporizes the layer of material around the fuel—a nearly perfect, lab-grown shell of diamond in the latest record-setter in December 2022. When that shell vaporizes, it drives the fuel inward as the carbon atoms fly outward. This generates a shockwave, which pushes the fuel so hard that the hydrogen fuses.

While the spherical fuel pellets are some of the most perfectly round objects humans have ever made, each has a deliberate flaw: a fill tube, where the fuel enters. Like a straw stuck in that crushed orange, this is the most likely place for a vortex-ring-led jet to form when the compression starts, the researchers explained.

"Fusion experiments happen so fast that we really only have to delay the formation of the jet for a few nanoseconds," said Eric Johnsen, an associate professor of mechanical engineering at U-M, who supervised the study.

The study brought together the fluid mechanics expertise of Wadas and Johnsen as well as the nuclear and plasma physics knowledge in the lab of Carolyn Kuranz, an associate professor of nuclear engineering and radiological sciences.

"In high-energy-density physics, many studies point out these structures, but haven’t clearly identified them as vortex rings," said Wadas.

Knowing about the deep body of research into the structures seen in fusion experiments and astrophysical observations, Wadas and Johnsen were able to draw on and extend that existing knowledge rather than trying to describe them as completely new features.

Johnsen is particularly interested in the possibility that vortex rings could help drive the mixing between heavy elements and lighter elements when stars explode, as some mixing process must have occurred to produce the composition of planets like Earth.

The model can also help researchers understand the limits of the energy that a vortex ring can carry, and how much fluid can be pushed before the flow becomes turbulent and harder to model as a result. In ongoing work, the team is validating the vortex ring model with experiments. 

The research is funded by Lawrence Livermore National Laboratory and the Department of Energy, with computational resources provided by the Extreme Science and Engineering Discovery Environment through the National Science Foundation and the Oak Ridge Leadership Computing Facility.

Study: Saturation of vortex rings ejected from shock-accelerated interfaces. (DOI: 10.1103/PhysRevLett.130.194001)

JOURNAL

Physical Review Letters

DOI

10.1103/PhysRevLett.130.194001 

Surprise W boson measurement could rewrite particle physics

Tereza Pultarova - Yesterday 
Space


A tiny subatomic particle called the W boson may be heavier than scientists have previously thought and it could shake up physics' grand theory of everything.

Scientists at the U.S. Fermi National Accelerator Laboratory spent 10 years analyzing mass measurements of the W boson, a lesser-known "sister particle" of the Higgs Boson that plays a role in radioactive decay. They found the particle is somewhat heavier than physics theories expected. And that, the scientists said in a statement, is quite a big deal, as it is at odds with the so-called Standard Model, a fundamental physics theory describing how the world on the microscale fits together.

"It's now up to the theoretical physics community and other experiments to follow up on this and shed light on this mystery," David Toback, a physicist at Texas A&M University, who is a member of the project, said in a statement. "If the difference between the experimental and expected value is due to some kind of new particle or subatomic interaction, which is one of the possibilities, there's a good chance it's something that could be discovered in future experiments."

Related: 10 mind-boggling things you should know about quantum physics

Some critics caution that it would take further experiments to verify those results as questioning the particle physics "bible" is a daring prospect.

The scientists behind the newest measurements are, however, quite confident in their results.

"The number of improvements and extra checking that went into our result is enormous," Ashutosh V. Kotwal of Duke University, who led the work, said in the statement. "We took into account our improved understanding of our particle detector as well as advances in the theoretical and experimental understanding of the W boson's interactions with other particles."

The scientists based their calculations on measurements from Fermilab's Tevatron collider conducted between 1985 and 2011. They then spent the following decade analyzing the data. Overall 4.2 million observations of W boson candidate particles were included in the analysis, which is about four times the number used in the earlier estimates the team published in 2012.

The new estimate is accurate to 0.01%, the scientists said in the statement.

The results were published in a paper in the journal Science on Thursday (April 7).

Follow Tereza Pultarova on Twitter @TerezaPultarova. 

Oddly heavy particle may have just broken the reigning model of particle physics

Paul Sutter - Yesterday
Live Science


An ultraprecise measurement of the mass of a subatomic particle called the W boson may diverge from the Standard Model, a long-reigning framework that governs the strange world of quantum physics.

After 10 years of collaboration using an atom smasher at Fermilab in Illinois, scientists announced this new measurement, which is so precise that they likened it to finding the weight of an 800-pound (363 kilograms) gorilla to a precision of 1.5 ounces (42.5 grams). Their result puts the W boson, a carrier of the weak nuclear force, at a mass seven standard deviations higher than the Standard Model predicts. That's a very high level of certainty, representing only an incredibly small probability that this result occurred by pure chance.

"While this is an intriguing result, the measurement needs to be confirmed by another experiment before it can be interpreted fully," Joe Lykken, Fermilab's deputy director of research, said in a statement.

The new result also disagrees with older experimental measurements of the W boson's mass. It remains to be seen if this measurement is an experimental fluke or the first opening of a crack in the Standard Model. If the result does stand up to scrutiny and can be replicated, it could mean that we need to revise or extend the Standard Model with possibly new particles and forces.

Related: Physicists get closer than ever to measuring the elusive neutrino

The strength of the weak nuclear force

The weak nuclear force is perhaps the strangest of the four fundamental forces of nature. It's propagated by three force carriers, known as bosons. There is the single Z boson, which has a neutral electric charge, and the W+ and W- bosons, which have positive and negative electric charges, respectively.

Because those three bosons have mass, they travel more slowly than the speed of light and eventually decay into other particles, giving the weak nuclear force a relatively limited range. Despite those limitations, the weak force is responsible for radioactive decay, and it is the only force (besides gravity) to interact directly with neutrinos, the mysterious, ghost-like particles that flood the universe.

Pinning down the masses of the weak force carriers is a crucial test of the Standard Model, the theory of physics that combines quantum mechanics, special relativity and symmetries of nature to explain and predict the behavior of the electromagnetic, strong nuclear and weak nuclear forces. (Yes, gravity is the "elephant in the room" that the model cannot explain.) The Standard Model is the most accurate theory ever developed in physics, and one of its crowning achievements was the successful prediction of the existence of the Higgs boson, a particle whose quantum mechanical field gives rise to mass in many other particles, including the W boson.

According to the Standard Model, at high energies the electromagnetic and weak nuclear forces combine into a single, unified force called the electroweak interaction. But at low energies (or the typical energies of everyday life), the Higgs boson butts in, driving a wedge between the two forces. Through that same process, the Higgs also gives mass to the weak force carriers.

If you know the mass of the Higgs boson, then you can calculate the mass of the W boson, and vice versa. For the Standard Model to be a coherent theory of subatomic physics, it must be consistent with itself. If you measure the Higgs boson and use that measurement to predict the W boson's mass, it should agree with an independent, direct measurement of the W boson's mass.

A flood of data

Using the Collider Detector at Fermilab (CDF), which is inside the giant Tevatron particle accelerator, a collaboration of more than 400 scientists examined years of data from over 4 million independent collisions of protons with antiprotons to study the mass of the W boson. During those super-energetic collisions, the W boson decays into either a muon or an electron (along with a neutrino). The energies of those emitted particles are directly connected to the underlying mass of the W boson.

"The number of improvements and extra checking that went into our result is enormous," said Ashutosh V. Kotwal, a particle physicist at Duke University who led the analysis. "We took into account our improved understanding of our particle detector as well as advances in the theoretical and experimental understanding of the W boson's interactions with other particles. When we finally unveiled the result, we found that it differed from the Standard Model prediction."

The CDF collaboration measured the value of the W boson to be 80,433 ± 9 MeV/c2, which is about 80 times heavier than the proton and about 0.1% heavier than expected. The uncertainty in the measurement comes from both statistical uncertainty (just like the uncertainty you get from taking a poll in an election) and systematic uncertainty (which is produced when your experimental apparatus doesn't always behave in the way you designed it to act). Achieving that level of precision — of an astounding 0.01% — is itself an enormous task, like knowing your own weight down to less than a quarter of an ounce.

"Many collider experiments have produced measurements of the W boson mass over the last 40 years," CDF co-spokesperson Giorgio Chiarelli, a research director at the Italian National Institute for Nuclear Physics, said in the statement. "These are challenging, complicated measurements, and they have achieved ever more precision. It took us many years to go through all the details and the needed checks."

Big result, small difference

The result differed from the Standard Model prediction of the W boson's mass, which is 80,357 ± 6 MeV/c2. The uncertainties in that calculation (the "±") come from uncertainties in the measurement of the Higgs boson and other particles, which must be inserted into the calculation, and from the calculation itself, which relies on several approximation techniques.

The differences between the results aren't very large in an absolute sense. Because of the high precision, however, they are separated by seven standard deviations, indicating the presence of a major discrepancy.

The new result also disagrees with previous measurements from other collider experiments, which have been largely consistent with the Standard Model prediction. It's not clear yet if this result is caused by some unknown bias within the experiment or if it's the first sign of new physics.

If the CDF result holds up and other experiments can verify it, it could be a sign that there's more to the W boson mass than its interaction with the Higgs. Perhaps a previously unknown particle or field, or maybe even dark matter, is interacting with the W boson in a way the Standard Model currently doesn't predict.

Nonetheless, the result is an important step in testing the accuracy of the Standard Model, said CDF co-spokesperson David Toback, a professor of physics and astronomy at Texas A&M University. "It's now up to the theoretical physics community and other experiments to follow up on this and shed light on this mystery," he said.

The researchers described their results April 7 in the journal Science.

Originally published on Live Science.

CERN at 70: Smashing elementary particles for humanity

Matthew Ward Agius

DW

September 25, 2024

CERN has been an epicenter of scientific breakthroughs since 1954, including the discovery of the Higgs boson.

 Scientists there hope a new, larger particle smasher will lead them to more discoveries for years to come.

The long tubes of CERN's Large Hadron Collider

Image: Martial Trezzini/Keystone/AP/picture alliance


The European Organization for Nuclear Research — better known as CERN — is a place of scientific breakthroughs.

Since 1954, thousands of the world's best scientists and emerging minds have converged on Switzerland to explore how the universe works. On September 29, CERN will celebrate its 70th anniversary.

CERN has been the seat of some of the most important discoveries in science — from the confirmation of the elusive Higgs boson in 2012, to more practical innovations like the invention of the World Wide Web.

The Large Hadron Collider

CERN is perhaps best known for its extensive underground particle accelerator known as the Large Hadron Collider (LHC) — a 27-kilometer-long (16-miles-long) tube built beneath the Swiss and French borderlands near Geneva.

Scientists have been accelerating particles around the LHC since September 2008.

The LHC works by sending separate, highly energized particle beams in opposite directions through the 27-kilometer-long tubular vacuum.

The particle beams consist of a type of particle called protons, which are guided by superconducting electromagnets, making them collide at almost the speed of light.

The particles are so tiny that the task of making them collide is like firing two needles 10 kilometers at each other with the precision to make them collide.

When the particles collide, they produce energy that is used to create new particles.

The LHC is one of 11 other particle accelerators based at CERN. Researchers use them to help advance a range of technologies, including some that impact our daily lives.

Their research has helped construct more powerful computers and microchips, improve the quality of technology used in healthcare, energy and space exploration.

Higgs boson breakthrough in 2012

At the top of CERN's agenda using the LHC was the ambition to find the Higgs boson particle.

The Higgs boson is a type of particle named after Nobel Prize physicist Peter Higgs. Higgs believed the particle created a field which fills the entire universe and gives other particles their mass.

In 2012, after decades of research, scientists at CERN finally found proof of Higgs' theory — they had found a Higgs boson.

It was a colossal scientific breakthrough that opened a whole new field of particle physics research and helped explain why particles bunched together at the formation of the universe.

Nobel Prize for 'God particle' discoverers  01:19

CERN aren't trying to create black holes

Prior to the LHC being switched on, there were concerns that smashing protons together at sub-light speed would lead to the formation of tiny black holes.

We think of black holes forming only when massive stars implode, but some theories suggest that tiny, quantum black holes can form when particles collide.

These tiny black holes are nothing like the black holes that suck matter inside them in space. They would only last for fractions of a second and be completely safe.

In fact, CERN researchers might like the formation of such a theoretical black hole inside a particle accelerator. It would give them an opportunity to see how gravity behaves on a quantum scale.

Peter Higgs, who along with Francois Englert won the 2013 Nobel Prize in Physics for his work on the Higgs boson.

Image: Sean Dempsey/AP Photo/picture alliance

What's next for CERN?

Scientists aren't finished with CERN's LHC. Beyond the discovery of the Higgs bosons, there are many other fundamental, unanswered questions about the universe.

They are developing a second-generation High Luminosity LHC. The upgrade will enable them to increase the number of proton collisions in the LHC to be at least five times.

This "LH-LHC" will likely be operational around 2041. Scientists aim to perform detailed studies of Higgs bosons by generating at least 15 million of the particles each year.

With the use of upgraded technology to generate more particles (and collisions), CERN hopes it will learn more about the once elusive Higgs boson, and discover new particles as yet unknown to science.

Edited by: Fred Schwaller

Mysteries of universe revealed? Hardly. CERN still fascinates on its 70th anniversary

The scientific center that is home to the world’s largest particle accelerator and is billed as the world’s biggest machine is celebrating its 70th anniversary

ByJAMEY KEATEN 

Associated Press
October 1, 2024

GENEVA -- The research center that is home to the world’s largest particle accelerator is celebrating its 70th anniversary on Tuesday, with the physicists who run it aiming to unlock secrets about dark matter and other mysteries to promote science for peace in today's conflict-darkened world.

Over the last seven decades, CERN, the sprawling research center on the Swiss-French border at Geneva, has become a household name in Europe, the West and beyond, but its complex inner workings remain a puzzle to many people.

Here's a look at CERN and how its discoveries have changed the world and our view of the universe — and could change them more in coming years.

The European Organization for Nuclear Research, which has retained the French-language acronym CERN for its predecessor outfit, had its origins in a 1951 meeting of the U.N.’s scientific organization that sought to build a state-of-the-art physics research facility in Europe and ease a brain drain toward America after World War II. Groundbreaking was on May 17, 1954.

Today, for cognoscenti, CERN is probably best known as home to the Large Hadron Collider, trumpeted as the world’s biggest machine, which powers a network of magnets to accelerate particles through a 27-kilometer (17-mile) underground loop in and around Geneva and slam them together at velocities approaching the speed of light.

By capturing and interpreting the results of the collisions — as many as a billion per second — of such beams of particles, thousands of scientists both on hand at the center and remotely around the world pore over the reams of resulting data and strive to explain how fundamental physics works.

CERN says collisions inside the LHC generate temperatures more than 100,000 times hotter than the core of the sun, on a small scale and in its controlled environment.

At the collider, “every day we are able to reproduce the conditions of the primordial universe as they were a millionth of a millionth of a second after the Big Bang. Yet, many open, crucial questions remain,” CERN Director-General Fabiola Gianotti told an anniversary celebration attended by many leaders of its 24 member countries.

Over the years, CERN and its experimental facilities have grown into a vast research hub with applications in many scientific fields and industries.

“In a world where conflicts between countries, religions and cultures sadly persist, this is a truly precious gift which cannot be taken for granted,” Gianotti said.


Experiments in the collider helped confirm in 2012 the subatomic Higgs boson, an infinitesimal particle whose existence had been theorized decades earlier and whose confirmation completed the Standard Model of particle physics.

CERN is also where the World Wide Web was born, in the mind of British scientist Tim Berners-Lee 35 years ago, as a way to help universities and institutes share information. In 1993, the software behind the web was put into the public domain — and the rest is history, in smartphones and on computers worldwide.

The spillover science and tools generated at CERN have rippled through the world economy. Thousands of smaller particle accelerators operate around the world today, plumbing applications in fields as diverse as medicine and computer chip manufacturing.

Crystals developed for CERN experiments roughly four decades ago are now widely used in PET scanners that can detect early signs of health troubles like cancer and heart disease.

“It is thanks to CERN that we have touch screens. It is thanks to CERN that we have new tools for fighting cancer," European Union chief Ursula von der Leyen said at the anniversary celebration. “You are constantly working with European industries to build low-emission airplanes, or to create new solutions to transport liquid hydrogen.”

"CERN is the living proof that science fosters innovation and that innovation fosters competitiveness,” von der Leyen said, adding that she wanted to increase spending for research in the next EU budget.

Some skeptics have over the years stirred fears about CERN. Insiders variously argue and explain that such fears are overblown or inaccurate, and CERN has issued its own retort to some of the theories out there.

For the most part, CERN technicians, researchers and theoreticians of more than 110 nationalities today carry out new experiments that aim to punch holes in the Standard Model — smashing up conventional understandings to move science forward — and explain a long list of lingering scientific unknowns.

Its scientific whizzes hope to solve riddles about dark energy — which makes up about 68% of the universe and has a role in speeding up its expansion — and test hypotheses about dark matter, whose existence is only inferred and which appears to outweigh visible matter nearly six-to-one, making up slightly more than a quarter of the universe.

CERN has two big projects on its horizon. The first is the High-Luminosity LHC project that aims to ramp up the number of collisions — and thus the potential for new discoveries — starting in 2029.

The second, over the much longer term, is the Future Circular Collider, which is estimated to cost 15 billion Swiss francs (about 16 billion euros or $17.2 billion) and is hoped to start operating in an initial phase by 2040.

Despite its aim to foster scientific progress in the cause of peace and humanity, CERN has found itself ensnared in politics.

Its constitution says the organization “shall have no concern with work for military requirements.” In 2022, CERN's governing council voted to pause ties with institutes in Russia because of President Vladimir Putin’s order for Russian troops to invade Ukraine earlier that year. Some fear that applications from CERN's research could make their way into Moscow's war machine.

On Nov. 30, CERN will formally exclude Russia — affecting some 500 scientists, about 100 of whom have joined non-Russian institutes in order to maintain their research with the center.

The suspension will come at a cost, depriving CERN of some 40 million Swiss francs in Russian financing for the High-Luminosity LHC. It amounts to about 4.5% of the budget for its experiment, which will now have to be shouldered by other CERN participants.

CERN counts 19 European Union countries plus Britain, Israel, Norway, Serbia and Switzerland as members, while the United States and Japan — plus the EU and the U.N. educational, scientific and cultural organization — have observer status. Russia and a Russia-based nuclear research institute had their observer status suspended in 2022.

 

Advisory panel issues field-defining recommendations for investments in particle physics research

Argonne is set to contribute to the realization of the recommendations, which will shape the next decade of discovery in particle physics

Reports and Proceedings

DOE/ARGONNE NATIONAL LABORATORY

Contributions from Argonne will drive innovation in particle physics and shed light on outstanding mysteries in the field.

Yesterday marked the release of a highly anticipated report from the Particle Physics Project Prioritization Panel (P5), unveiling an exciting new roadmap for unlocking the secrets of the cosmos through particle physics.

The report was released by the High Energy Physics Advisory Panel to the High Energy Physics program of the Office of Science of the U.S. Department of Energy (DOE) and the National Science Foundation’s Division of Physics. It outlines particle physicists’ recommendations for research priorities in a field whose projects — such as building new accelerator facilities — can take years or decades, contributions from thousands of scientists and billions of dollars

The 2023 P5 report represents the major activity in the field of particle physics that delivers recommendations to U.S. funding agencies. This year’s report builds on the output of the 2021 Snowmass planning exercise — a process organized by the American Physical Society’s (APS) Division of Particles and Fields that convened particle physicists and cosmologists from around the world to outline research priorities. This membership division constitutes the only independent body in the U.S. that represents particle physics as a whole.

“With our state-of-the-art facilities and community of dedicated scientists, Argonne’s contributions are shaping the global trajectory of high-energy physics.” — Rik Yoshida, Argonne High Energy Physics Division Director

“The P5 report will lay the foundation for a very bright future in the field,” said R. Sekhar Chivukula, 2023 chair of the APS Division of Particles and Fields and a distinguished professor of physics at the University of California, San Diego. ​“There are extraordinarily important scientific questions remaining in particle physics, which the U.S. particle physics community has both the capability and opportunity to help address, within our own facilities and as a member of the global high energy physics community.”

The report includes a range of budget-conscious recommendations for federal investments in research programs, the U.S. technical workforce and the technology and infrastructure needed to realize the next generation of transformative discoveries related to fundamental physics and the origin of the universe. For example, the report recommends continued support for the Deep Underground Neutrino Experiment (DUNE), based out of DOE’s Fermilab in Illinois, for CMB-S4, a network of ground-based telescopes designed to observe the cosmic microwave background (CMB), and for the planned expansion of the South Pole’s neutrino observatory, an international collaboration known as IceCube-Gen2, in a facility operated by the University of Wisconsin–Madison.

Researchers at DOE’s Argonne National Laboratory stand at the forefront of high energy physics and are poised to contribute significantly to the advancement of the field over the next decade. They are exploring the fundamental nature of the universe and pioneering innovative technologies with far-reaching implications. In particular, Argonne’s High Energy Physics (HEP) division leverages the laboratory’s suite of multidisciplinary facilities and equipment — including world-class scientific computing capabilities — to further scientific discovery and advance accelerator technology. For example, Argonne’s contributions to key high energy physics collaborations include the design and fabrication of components for DUNE, the development of cutting-edge detectors for CMB-S4 and more.

“With our state-of-the-art facilities and community of dedicated scientists, Argonne’s contributions are helping to shape the global trajectory of high-energy physics,” said Rik Yoshida, director of Argonne’s HEP division. ​“This report reflects the collective wisdom of the high energy physics community, and we look forward to leveraging our expertise and capabilities here at Argonne to help uncover the mysteries of the universe, drive innovation, inspire future generations of scientists and bolster our nation’s vital role in the future of particle physics.”

“In the P5 exercise, it’s really important that we take this broad look at where the field of particle physics is headed, to deliver a report that amounts to a strategic plan for the U.S. community with a 10-year budgetary timeline and a 20-year context. The panel thought about where the next big discoveries might lie and how we could maximize impact within budget, to support future discoveries and the next generation of researchers and technical workers who will be needed to achieve them,” said Karsten Heeger, P5 panel deputy chair and Eugene Higgins Professor and chair of physics at Yale University.

New knowledge, and new technologies, set the stage for the most recent Snowmass and P5 convenings. ​“The Higgs boson had just been discovered before the previous P5 process, and now our continued study of the particle has greatly informed what we think may lie beyond the standard model of particle physics,” said Hitoshi Murayama, P5 panel chair and the MacAdams Professor of physics at the University of California, Berkeley. ​“Our thinking about what dark matter might be has also changed, forcing the community to look elsewhere — to the cosmos. And in 2015, the discovery of gravitational waves was reported. Accelerator technology is changing too, which has shifted the discussion to the technology R&D needed to build the next-generation particle collider.”

The U.S. participates in several major international scientific collaborations in high energy physics and cosmology, including the European Council for Nuclear Research (CERN), which operates the Large Hadron Collider, where the Higgs boson was discovered in 2012. The P5 report recommends that the U.S. support a significant in-kind contribution to a new international facility, the ​“Higgs factory,” to further our understanding of the

Advisory panel issues field-defining recommendations for US government investments in particle physics research

Activities of the Particle Physics Project Prioritization Panel are supported in part by the American Physical Society’s Division of Particles and Fields

Reports and Proceedings

AMERICAN PHYSICAL SOCIETY

The High Energy Physics Advisory Panel (HEPAP) to the High Energy Physics program of the Office of Science of the U.S. Department of Energy and the National Science Foundation’s Division of Physics has released a new Particle Physics Project Prioritization Panel (P5) report, which outlines particle physicists’ recommendations for research priorities in a field whose projects — such as building new accelerator facilities — can take years or decades, contributions from thousands of scientists, and billions of dollars. 

The 2023 P5 report represents the major activity in the field of particle physics that delivers recommendations to U.S. funding agencies. This year’s report builds on the output of the 2021 Snowmass planning exercise — a process organized by the American Physical Society (APS)’s Division of Particles and Fields that convened particle physicists and cosmologists from around the world to outline research priorities. This membership division constitutes the only independent body in the United States that represents particle physics as a whole.

“The P5 report will lay the foundation for a very bright future in the field,” said R. Sekhar Chivukula, 2023 chair of the APS Division of Particles and Fields and a Distinguished Professor of Physics at the University of California, San Diego. “There are extraordinarily important scientific questions remaining in particle physics, which the U.S. particle physics community has both the capability and opportunity to help address, within our own facilities and as a member of the global high energy physics community.”

The report includes a range of budget-conscious recommendations for federal investments in research programs, the U.S. technical workforce, and the technology and infrastructure needed to realize the next generation of transformative discoveries related to fundamental physics and the origin of the universe. For example, the report recommends continued support for the 

Deep Underground Neutrino Experiment (DUNE), based out of Fermilab in Illinois, for CMB-S4, a network of ground-based telescopes designed to observe the cosmic microwave background, and for the planned expansion of the South Pole’s neutrino observatory, an international collaboration known as IceCube-Gen2, in a facility operated by the University of Wisconsin–Madison. 

“In the P5 exercise, it’s really important that we take this broad look at where the field of particle physics is headed, to deliver a report that amounts to a strategic plan for the U.S. community with a 10-year budgetary timeline and a 20-year context. The panel thought about where the next big discoveries might lie and how we could maximize impact within budget, to support future discoveries and the next generation of researchers and technical workers who will be needed to achieve them,” said Karsten Heeger, P5 panel deputy chair and Eugene Higgins Professor and chair of physics at Yale University.

New knowledge, and new technologies, set the stage for the most recent Snowmass and P5 convenings. “The Higgs boson had just been discovered before the previous P5 process, and now our continued study of the particle has greatly informed what we think may lie beyond the standard model of particle physics,” said Hitoshi Murayama, P5 panel chair and the MacAdams Professor of physics at the University of California, Berkeley. “Our thinking about what dark matter might be has also changed, forcing the community to look elsewhere — to the cosmos. And in 2015, the discovery of gravitational waves was reported. Accelerator technology is changing too, which has shifted the discussion to the technology R&D needed to build the next-generation particle collider.”  

The United States participates in several major international scientific collaborations in high energy physics and cosmology, including the European Council for Nuclear Research (CERN), which operates the Large Hadron Collider, where the Higgs boson was discovered in 2012. The P5 report recommends that the United States support a significant in-kind contribution to a new international facility, the ‘Higgs factory,’ to further our understanding of the Higgs boson. It also recommends that the United States study the possibility of hosting the next most-advanced particle collider facility, to reinforce the country’s leading role in international high energy physics for decades to come.

# # #

The American Physical Society is a nonprofit membership organization working to advance and diffuse the knowledge of physics through its outstanding research journals, scientific meetings, and education, outreach, advocacy, and international activities. APS represents more than 50,000 members, including physicists in academia, national laboratories, and industry in the United States and throughout the world.

BNL: Advisory panel issues field-defining recommendations for U.S. government investments in particle physics research

Reports and Proceedings

DOE/BROOKHAVEN NATIONAL LABORATORY

The following news release on the 2023 Particle Physics Project Prioritization Panel (P5) report is based on one issued today by the American Physical Society (APS) with added content specific to the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory. For more information about Brookhaven Lab’s research in particle physics, contact: Karen McNulty Walsh, kmcnulty@bnl.gov, (631) 344-8350. For APS media inquiries, contact Anna Torres, torres@aps.org, (301) 209-3605.

WASHINGTON, D.C.—The High Energy Physics Advisory Panel (HEPAP) to the High Energy Physics program of the Office of Science of the U.S. Department of Energy and the National Science Foundation’s Division of Physics has released a new Particle Physics Project Prioritization Panel (P5) report, which outlines particle physicists’ recommendations for research priorities in the field. The 2023 P5 report was posted online yesterday and was voted on and accepted by HEPAP today.

The 2023 P5 report represents the major activity in the field of particle physics that delivers recommendations to U.S. funding agencies. This year’s report builds on the output of the 2021 Snowmass planning exercise—a process organized by the American Physical Society (APS)’s Division of Particles and Fields that convened particle physicists and cosmologists from around the world to outline research priorities. This membership division constitutes the only independent body in the United States that represents particle physics as a whole.

“The P5 report will lay the foundation for a very bright future in the field,” said R. Sekhar Chivukula, 2023 chair of the APS Division of Particles and Fields and a Distinguished Professor of Physics at the University of California, San Diego. “There are extraordinarily important scientific questions remaining in particle physics, which the U.S. particle physics community has both the capability and opportunity to help address, within our own facilities and as a member of the global high energy physics community.”

“We welcome the P5 report recommendations, which define a strong and balanced U.S. particle physics program based on input from the Snowmass community-wide process,” said Brookhaven National Laboratory Director JoAnne Hewett. “Building on our decades of expertise in high energy physics and facility design and operation, we are eager to actively engage and lead in developing, constructing, and operating the next generation of facilities and experiments to explore the Quantum Universe.”

The report includes a range of budget-conscious recommendations for federal investments in research programs, the U.S. technical workforce, and the technology and infrastructure needed to realize the next generation of transformative discoveries related to fundamental physics and the origin of the universe. For example, the report recommends continued support for the high-luminosity upgrades at the Large Hadron Collider (LHC), based in Europe, for the Deep Underground Neutrino Experiment (DUNE), based out of Fermilab in Illinois, for CMB-S4, a network of ground-based telescopes designed to observe the cosmic microwave background, and for the planned expansion of the South Pole’s neutrino observatory, an international collaboration known as IceCube-Gen2, in a facility operated by the University of Wisconsin–Madison.

“In the P5 exercise, it’s really important that we take this broad look at where the field of particle physics is headed, to deliver a report that amounts to a strategic plan for the U.S. community with a 10-year budgetary timeline and a 20-year context. The panel thought about where the next big discoveries might lie and how we could maximize impact within budget, to support future discoveries and the next generation of researchers and technical workers who will be needed to achieve them,” said Karsten Heeger, P5 panel deputy chair and Eugene Higgins Professor and chair of physics at Yale University.

New knowledge, and new technologies, set the stage for the most recent Snowmass and P5 convenings. “The Higgs boson had just been discovered before the previous P5 process, and now our continued study of the particle has greatly informed what we think may lie beyond the standard model of particle physics,” said Hitoshi Murayama, P5 panel chair and the MacAdams Professor of physics at the University of California, Berkeley. “Our thinking about what dark matter might be has also changed, forcing the community to look elsewhere—to the cosmos. And in 2015, the discovery of gravitational waves was reported. Accelerator technology is changing too, which has shifted the discussion to the technology R&D needed to build the next-generation particle collider.”

The United States participates in several major international scientific collaborations in high energy physics and cosmology, including the European Council for Nuclear Research (CERN), which operates the Large Hadron Collider, where the Higgs boson was discovered in 2012. The P5 report recommends that the United States support a significant in-kind contribution to a new international facility, the ‘Higgs Factory,’ to further our understanding of the Higgs boson. It also recommends that the United States study the possibility of hosting the next most-advanced particle collider facility, to reinforce the country’s leading role in international high energy physics for decades to come.

DOE’s Brookhaven National Laboratory contributes to many of the projects highlighted in the P5 report, including these major efforts:

Brookhaven Lab serves as the U.S. host laboratory for the ATLAS experiment, one of four major detectors at the LHC. ATLAS has opened new frontiers of knowledge about elementary particles and their interactions, including the 2012 discovery of the Higgs boson. Brookhaven Lab scientists contributed to that groundbreaking discovery and subsequent studies of Higgs properties, as well as ATLAS project management and experiment operations. They also run a state-of-the-art computing center for storing and sharing ATLAS data with collaborators around the world. Brookhaven physicists, engineers, and technical staff also helped design and build the magnets that steer the LHC’s beams of protons and other ions into collisions—including magnets enabling drastically increased collision rates for future discoveries.

In addition, the Brookhaven team has proposed ideas for and is dedicated to working closely with international and U.S. partners to develop a Higgs factory and its associated detectors. This facility, as recommended in the P5 report, would create copious numbers of Higgs particles and allow detailed, precision studies of their properties—potentially opening the door to discovering discrepancies between theory and experiment that could reveal new physics. The P5 panel also recommends dedicated R&D to explore a suite of promising future projects, including colliders that can reach even higher energies than Higgs factories. Brookhaven scientists are actively engaged in the development of technologies for one such approach—a machine that could collide particles called muons, heavy cousins of electrons.

Brookhaven Lab is also playing a leading role in DUNE. This Fermilab-based experiment will send beams of elusive subatomic particles called neutrinos hundreds of miles through Earth’s crust to detectors deep underground in South Dakota. Understanding how neutrinos change as they travel may help unravel mysteries about how our universe evolved, including potentially an asymmetry between matter and antimatter that accounts for our universe being composed mostly of matter. Brookhaven physicists and staff helped develop the methods for creating neutrinos, simulations for testing and controlling characteristics of the beam, specialized electronics and other detector materials needed to study key neutrino characteristics, and the software and computational tools that will be used to capture neutrino signals and process vast quantities of data. Brookhaven scientists are leading the design of a third underground detector module for DUNE, highlighted in the P5 report as part of a re-envisioned second phase of this project.

Going beyond the secrets of the matter that makes up our world and its scantly present antimatter partner, Brookhaven scientists seek to explore the unknowns of so-called dark matter and dark energy, which are highlighted among the scientific drivers for new discoveries by the P5 panel and together make up more than 95% of our universe. One tool for this research is a telescope that will be housed at the Vera C. Rubin Observatory high on a mountaintop in Chile. The DOE-funded effort to build the camera for the telescope was managed by SLAC National Accelerator Laboratory. Brookhaven Lab led construction of the camera’s 3.2 gigapixel “digital film”—the biggest charge-coupled device (CCD) array ever built—and will support the telescope’s Legacy Survey of Space and Time (LSST). LSST will be an unparalleled wide-field astronomical survey of our universe—wider and deeper in volume than all previous surveys combined.

Brookhaven Lab is also actively engaged in developing small- and medium-scale facilities and experiments and in building capabilities in machine learning/artificial intelligence, quantum information science, and microelectronics that will help to push the frontiers of discovery in high energy physics with potential benefit for other fields. The Lab is also committed to attracting, building, and supporting a diverse workforce to carry out these ambitious research programs, and to fostering a climate of innovation.

# # #

Activities of the Particle Physics Project Prioritization Panel are supported in part by
the American Physical Society’s Division of Particles and Fields

The American Physical Society is a nonprofit membership organization working to advance and diffuse the knowledge of physics through its outstanding research journals, scientific meetings, and education, outreach, advocacy, and international activities. APS represents more than 50,000 members, including physicists in academia, national laboratories, and industry in the United States and throughout the world.

Brookhaven National Laboratory is supported by the Office of Science of the U.S. Department of Energy. The Office of Science is the single largest supporter of basic research in the physical sciences in the United States and is working to address some of the most pressing challenges of our time. For more information, visit science.energy.gov.

Follow @BrookhavenLab on social media. Find us on Instagram, LinkedIn, Twitter, and Facebook. Higgs boson.

It also recommends that the U.S. study the possibility of hosting the next most-advanced particle collider facility to reinforce the country’s leading role in international high energy physics for decades to come.

Activities of the P5 are supported in part by the APS’s Division of Particles and Fields.

The American Physical Society is a nonprofit membership organization working to advance and diffuse the knowledge of physics through its outstanding research journals, scientific meetings, and education, outreach, advocacy, and international activities. APS represents more than 50,000 members, including physicists in academia, national laboratories, and industry in the United States and throughout the world.

Argonne National Laboratory seeks solutions to pressing national problems in science and technology. The nation’s first national laboratory, Argonne conducts leading-edge basic and applied scientific research in virtually every scientific discipline. Argonne researchers work closely with researchers from hundreds of companies, universities, and federal, state and municipal agencies to help them solve their specific problems, advance America’s scientific leadership and prepare the nation for a better future. With employees from more than 60 nations, Argonne is managed by UChicago Argonne, LLC for the U.S. Department of Energy’s Office of Science.

The U.S. Department of Energy’s Office of Science is the single largest supporter of basic research in the physical sciences in the United States and is working to address some of the most pressing challenges of our time. For more information, visit https://​ener​gy​.gov/​s​c​ience.