PAKISTAN

ISI and MI say Imran Riaz not in their custody, senior cop tells LHC

Rana Bilal 

DAWN

Published May 25, 2023 

Lahore police Deputy Inspector General (Investigation) Kamran Adil told the high court on Thursday that both the Inter-Services Intelligence (ISI) and the Military Intelligence (MI) had said that anchorperson Imran Riaz Khan — whose whereabouts remain unknown since his arrest on May 11 — was not in their custody.

The police official made the remarks as the Lahore High Court (LHC) resumed hearing a plea seeking the recovery of the anchorperson, who was among the individuals apprehended in the wake of protests that erupted in the country after the arrest of PTI chairman Imran Khan.

Later, his lawyer told Dawn.com that a writ petition was filed on May 12 over the anchorperson’s arrest and the LHC directed the attorney general to present him before the court the same day. But, after its orders were not followed, Sialkot police were given a 48-hour deadline to recover Imran.

A first information report (FIR) pertaining to the matter was registered with Civil Lines police on May 16 on the complaint of the anchorperson’s father, Muhammad Riaz.


The FIR was registered against “unidentified persons” and police officials for allegedly kidnapping Imran, invoking Section 365 (kidnapping or abducting with intent secretly and wrongfully to confine person) of the Pakistan Penal Code.

At the previous hearing, Punjab Inspector General Dr Usman Anwar had told the court that there was no trace of the journalist at any police department across the country.

The LHC had subsequently directed the ministries of interior and defence to “discharge their constitutional duties to effect the recovery” of the missing anchorperson.
The hearing

LHC Chief Justice Muhammad Ameer Bhatti presided over today’s hearing during which the Lahore police DIG (Investigation) appeared before the court instead of the Punjab IG.

The lawyer representing the Punjab government requested the court to exempt the provincial police chief from appearing as he was attending a ceremony in connection with Martyrs Respect Day in Gujranwala.

The LHC CJ inquired about the IG’s schedule and asked for the record to be submitted. The DIG assured the court that the record would be submitted to the court.

During the hearing, the DIG stated, “The ISI and MI have said that Imran Riaz is not in their custody”.

Meanwhile, the anchorperson’s counsel, Advocate Azhar Siddique, told the court that Imran’s father, Muhammad Riaz, wished to speak.

Justice Bhatti emphasised the court’s commitment to upholding fundamental rights while Riaz said his son was “being punished for making a vlog”.

The court directed the journalist’s lawyers to meet with the police team later today and told them to provide the police with any evidence that was in their possession.

The hearing was later adjourned.
Info minister called out for remarks on Imran’s disappearance

Earlier this week, journalists and human rights activists had strongly criticised Information Minister Marriyum Aurangzeb’s comments regarding Imran’s case.

Journalist Secunder Kermani, a Channel4 News foreign correspondent, had shared a video of an exchange with the information minister about the missing anchorperson.



He questioned Aurangzeb about journalists going missing and being detained, adding that these were the same issues that the PML-N had raised as matters of concern when in opposition during the previous PTI government.

In response, Aurangzeb asked Kermani to name even a single journalist who was missing. When Kermani mentioned Imran, the minister responded, “Imran Riaz is a political party spokesperson now. You really have to draw [a] distinction.”

She further said, “You have to differentiate between journalists and the journalists who have joined political parties. Once they have joined political parties, they are inciting violence, they are spokespersons of that political parties.”

Aurangzeb’s response elicited severe criticism from several journalists and rights activists, who reminded the minister that a person’s disappearance was an issue of basic human rights irrespective of what political party they favoured.

Lawyer and social activist Jibran Nasir said that Aurangzeb believed Imran “should be seen as a supporter of PTI and hence considered a sub-human who deserves the treatment being meted out to them.

“Now just imagine the plight of ordinary citizens suffering military trials,” he added.

Pakistan Initiative at Atlantic Council’s South Asia Centre Director Uzair Younus said Imran’s status as a journalist or not should not matter.

He said that Imran had fundamental constitutional rights granted to him on account of his Pakistani citizenship.

“Stop violating his rights and those of countless others. These disappearances are heinous!” he tweeted.

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.

 

Large Hadron Collider experiment zeroes in on magnetic monopoles

by Ana Lopes, CERN

The MoEDAL detector. Credit: CERN

The late physicist Joseph Polchinski once said the existence of magnetic monopoles is "one of the safest bets that one can make about physics not yet seen." In its quest for these particles, which have a magnetic charge and are predicted by several theories that extend the Standard Model, the MoEDAL collaboration at the Large Hadron Collider (LHC) has not yet proven Polchinski right, but its latest findings mark a significant stride forward.

The results, reported in two papers posted on the arXiv preprint server, considerably narrow the search window for these hypothetical particles.

At the LHC, pairs of magnetic monopoles could be produced in interactions between protons or heavy ions. In collisions between protons, they could be formed from a single virtual photon (the Drell–Yan mechanism) or the fusion of two virtual photons (the photon-fusion mechanism). Pairs of magnetic monopoles could also be produced from the vacuum in the enormous magnetic fields created in near-miss heavy-ion collisions, through a process called the Schwinger mechanism.

Since it started taking data in 2012, MoEDAL has achieved several firsts, including conducting the first searches at the LHC for magnetic monopoles produced via the photon-fusion mechanism and through the Schwinger mechanism.

In the first of its latest studies, the MoEDAL collaboration sought monopoles and high-electric-charge objects (HECOs) produced via the Drell–Yan and photon-fusion mechanisms. The search was based on proton–proton collision data collected during Run 2 of the LHC, using the full MoEDAL detector for the first time.

The full detector comprises two main systems sensitive to magnetic monopoles, HECOs and other highly ionizing hypothetical particles. The first can permanently register the tracks of magnetic monopoles and HECOs, with no background signals from Standard Model particles. These tracks are measured using optical scanning microscopes at INFN Bologna.

The second system consists of roughly a ton of trapping volumes designed to capture magnetic monopoles. These trapping volumes—which make MoEDAL the only collider experiment in the world that can definitively and directly identify the magnetic charge of magnetic monopoles—are scanned at ETH Zurich using a special type of magnetometer called a SQUID to look for any trapped monopoles they may contain.

In their latest scanning of the trapping volumes, the MoEDAL team found no magnetic monopoles or HECOs, but it set bounds on the mass and production rate of these particles for different values of particle spin, an intrinsic form of angular momentum.

For magnetic monopoles, the mass bounds were set for magnetic charges from 1 to 10 times the fundamental unit of magnetic charge, the Dirac charge (gD), and the existence of monopoles with masses as high as about 3.9 trillion electronvolts (TeV) was excluded.

For HECOs, the mass limits were established for electric charges from 5e to 350e, where e is the electron charge, and the existence of HECOs with masses ranging up to 3.4 TeV was ruled out.

"MoEDAL's search reach for both monopoles and HECOs allows the collaboration to survey a huge swathe of the theoretical 'discovery space' for these hypothetical particles," says MoEDAL spokesperson James Pinfold.

In its second latest study, the MoEDAL team concentrated on the search for monopoles produced via the Schwinger mechanism in heavy-ion collision data taken during Run 1 of the LHC. In a unique endeavor, it scanned a decommissioned section of the CMS experiment beam pipe, instead of the MoEDAL detector's trapping volumes, in search of trapped monopoles.

Once again, the team found no monopoles, but it set the strongest-to-date mass limits on Schwinger monopoles with a charge between 2gD and 45gD, ruling out the existence of monopoles with masses of up to 80 GeV.

"The vital importance of the Schwinger mechanism is that the production of composite monopoles is not suppressed compared to that of elementary ones, as is the case with the Drell–Yan and photon-fusion processes," explains Pinfold. "Thus, if monopoles are composite particles, this and our previous Schwinger-monopole search may have been the first-ever chances to observe them."

The MoEDAL detector will soon be joined by the MoEDAL Apparatus for Penetrating Particles, MAPP for short, which will allow the experiment to cast an even broader net in the search for new particles.

More information: Search for Highly-Ionizing Particles in pp Collisions During LHC Run-2 Using the Full MoEDAL Detector, arXiv (2023). DOI: 10.48550/arxiv.2311.06509

B. Acharya et al, MoEDAL search in the CMS beam pipe for magnetic monopoles produced via the Schwinger effect, arXiv (2024). DOI: 10.48550/arxiv.2402.15682

Journal information: arXiv 

Provided by CERN ATLAS experiment places some of the tightest limits yet on magnetic monopoles

ATLAS searches for new phenomena using unsupervised machine learning for anomaly detection

24 August 2023 |

ATLAS Collaboration

Since starting up in 2009, the Large Hadron Collider (LHC) has been at the forefront of scientific exploration – with researchers driven to uncover new particles and phenomena that go beyond the Standard Model. Over the years, thousands of scientists have channelled their expertise into refining analysis techniques and developing new ways to find these new-physics phenomena.

Figure 1: A schematic representation of the autoencoder architecture used for training and selection of the three anomaly regions. (Image: ATLAS Collaboration)

Traditionally, searches for new physics use complex computer simulations to reproduce what Standard Model processes should look like in collisions recorded by the ATLAS Experiment. These are then compared to simulations of new-physics models (e.g. dark matter, supersymmetry, etc.). Such models also help physicists determine the types of collisions where new-physics processes would be very prominent or where the collisions cannot be described by Standard-Model simulations – thus focusing their searches for new phenomena. Another style of searches involves looking at small deviations to a Standard-Model background caused by possible new phenomena.

Unsupervised machine learning can offer a new style of analyses which is completely agnostic to types of new-physics models and to any expectations of scientists. Researchers can design a complex neural network with millions of interconnections between “neurons”, and train this network on real data (see Figure 1). After training, the neural network can recognise “typical” LHC collisions and filter them out, leaving behind only the unrecognised or “atypical” collision events. On a technical side, such an unsupervised deep neural network (called an autoencoder) compresses input information, and then decompresses it while comparing inputs with outputs. Events with large reconstruction differences are called an “anomaly” since the algorithm finds itself in “trouble” in identifying such events. The chances that the anomalous events belong to new-physics phenomena are high. When using such neural networks, the idea is to look at the anomalous events, reconstruct the invariant masses of the particles in the collision, and then decide if they can be described by a Standard-Model process.

The new ATLAS result pioneers the use of unsupervised machine learning to search for anomalous collision events which could be from new-physics phenomena.

Figure 2: Example of the invariant mass (jet+muon) in the anomalous region defined by the unsupervised machine learning algorithm trained on a fraction of real data. The fit is represented by the red line, while the associated statistical uncertainties are indicated by the shaded band.The lower panel shows the bin-by-bin significances of deviations from the fit. (Image: ATLAS Collaboration)

In a new paper submitted to Phys. Rev. Lett., the ATLAS Collaboration pioneers the use of this style of physics analysis using LHC Run-2 data (collected 2015-2018). This analysis is the first of its kind, and marks the inaugural application of this type of unsupervised machine learning at a collider experiment, whether at the LHC or elsewhere.

ATLAS physicists observed no significant deviations from the Standard Model in the anomaly regions. The largest deviation was found for a mass at around 4.8 TeV with a significance of about 2.9 sigma for one decay channel (Figure 2). This level of statistical confidence typically means that the experimental observation could be a promising hint, but not sufficient for claiming the observation. The event display in the header of this briefing illustrates a typical collision event in the anomaly region with the jet+muon mass where the largest deviation is observed.

This analysis technique offers a new paradigm for searching for new-physics phenomena. One that relies less on wondering how the “new” phenomena may look, and instead focusing on new and unexpected model-agnostic signatures. In short, continuing the decade-long tradition of LHC physicists to discover a path into the unexplored realms of physics.About the event display: A display of an event with the reconstructed invariant mass of 4.72 TeV in the anomaly region as reported by the autoencoder trained using ATLAS data. The grey cones represent jets and the red lines represent muons. The green arrow indicates a missing transverse energy (MET). The red line closest to MET represents a high-energy muon. (Image: ATLAS Collaboration)

Learn more

Search for new phenomena in two-body invariant mass distributions using unsupervised machine learning for anomaly detection at 13 TeV with the ATLAS detector (arXiv:2307.01612, see figures)
EPS-HEP 2023 poster by Alkaid Cheng: 

Search for new physics using unsupervised machine learning for anomaly detection in 13 TeV collisions recorded by the ATLAS detector at the LHC
LHCP 2023 parallel talk by Rui Zhang:

  Search for new physics using unsupervised machine learning for anomaly detection with ATLAS
BOOST 2023 parallel talk by Wasikul Islam:

  Search for new phenomena in two-body invariant mass distributions using unsupervised machine learning for anomaly detection with the ATLAS detector

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 

A THEORY IN SEARCH OF EVIDENCE

Dark matter: Why we keep searching for something that may not even exist

Our understanding of the universe keeps improving. But there's a huge invisible force out there called dark matter and we're virtually clueless about it.

Astrophysicists say the James Webb Space Telescope may help them detect,

 if not see, dark matter in the universe

It has never been detected, only speculated. But scientists estimate that up to 85% of the matter in the universe could be made of what's called dark matter.

Scientists cannot define dark matter with any certainty, but that hasn't stopped the search for it. Our largest and newest space-based telescope, the James Webb Space Telescope is on the case.

It was barely moments after the first images taken by the telescope had been released on July 12, 2022, when Kai Noeske said something both mysterious and true.

Noeske, an astronomer at the European Space Observation Centre (ESOC) in Darmstadt, Germany, was pointing to an image of Stephan's Quintet, a group of five galaxies, as they have never been seen before.

Astronomer Kai Noeske looked at the image of Stephan's Quintet and said:

 "There is a lot out there that we do not know [...] One of those things could be dark matter."

And he said: "There is a lot out there that we do not know. And we do not know what we do not know. [But] one of those things could be dark matter." 

An accidental discovery

In the 19th century, Lord Kelvin, a Scottish-Irish physicist, wanted to estimate the mass of our galaxy, the Milkyway, using data on how fast stars moved around the galaxy's core.

But Kelvin found discrepancies or anomalies in the data, things which could not be explained and were attributed to "dark bodies" that we cannot see.

"The galaxy seems to be rotating much faster than it should, based on estimates," explained Tevong You, a theorist at CERN, the European Organization for Nuclear Research.

The Large Hadron Collider is the world's most powerful particle accelerator

The theory is that there is an "invisible matter" responsible for the speed at which our galaxy rotates, said You. And that may be true of other galaxies as well.

Stars have been observed to travel at higher-than-estimated speeds, especially at the edges of galaxies. And that is weird.

Stars should cut loose and 'fly off'

Imagine you attached a stone to a string, and you rotated it at high speed. The stone would cut loose and fly off if it reached a speed higher than a certain threshold — a point at which the string becomes too weak to hold onto the stone, as the stone picks up speed and gains more force.

But astronomers have observed stars that continue to spin around the center of the galaxy, even when the string holding them to the galaxy, as it were, should have ripped, and the stars should have "flown off".

The astronomers' only explanation is that there must be some invisible matter holding the stone in range. Perhaps it's this elusive dark matter?

That remains an unanswered question. And there are many other anomalies, such as the shape of some galaxies, including our Milkyway, that are so far unexplained.

We can't see dark matter but we may see its effects

Scientists say that the reason we are unable to see or detect this invisible matter is that it does not interact with electromagnetic forces — things like visible light, X-ray or radio waves.

They argue that we can, however, observe some of the effects of dark matter through its gravitational force.

But we still want to detect dark matter in its own right. And here's where CERN's Large Hadron Collider comes in. Tevong You and other researchers at CERN think the LHC is our best chance of detecting dark matter.

When particles collide at the LHC, the resulting debris gets caught in detectors

 such as this one. This is a illustrating one of the LHC's detectors.

A decade ago, experiments at the LHC proved the Standard Model of particle physics by detecting the Higgs boson particle — a particle which itself had long proved to be elusive.

The Standard Model is the idea that everything in the universe is made of a few fundamental particles and that those are governed by four fundamental forces — the strong force, the weak force, the electromagnetic force, and the gravitational force.

Tevong You said that the LHC could help solve the mystery of dark matter. But even now, You suspects that dark matter will be nothing like the particles we know from the Standard Model.

"It has to interact very weakly. It can't interact with light or electromagnetism. It can't interact with the strong force, and it may interact through the weak force that causes radioactivity," said You.

If that reads like a riddle, you're not alone. Scientists are still trying to work it out themselves.

Measuring dark matter by what's missing

The Large Hadron Collider smashes particles together to create collisions. The collisions produce a debris that gets caught by particle detectors.

It's just the same as if you smashed two apples together, bits would spray in all directions and get caught on the walls and floor. Those bits of apple would still be fruit, but they would have also become somewhat different. Even so, if we then collected all the bits of apple, including the juices, we would theoretically have all the bits to reconstruct those two original apples.

And the same is true of fundamental particles. We smash them up, they split and spray against the LHC detectors, and if we piece them back together, we should be able to account for all the bits that made those original particles.  

But if after all that, we find that there is something missing... especially missing energy or mass, as energy is also known... Well, when it comes to particle physics, scientists tend to think that there would have to be some dark, or invisible, matter — elements that we can't see, but which are very much part of the whole thing.

Andre David is an experimental physicist at CERN who builds particle detectors and says that if there is missing energy after a collision, it is likely that that energy has been transferred to dark matter. 

"The Higgs boson interacts with all the other elements that have mass. And so dark matter must [also] have mass in order to fulfill the effect that we see in the galaxies," said David.

New theories about dark matter

Some scientists argue that if there were invisible forces in the universe, we would have found them already and that, given that we haven't detected those forces, they suggest we should think outside of the Standard Model.

One of those scientists is the physicist Mordehai Milgrom. Milgrom has developed an alternative theory of gravity, one that suggests that gravitational force operates differently at different distances from the core of a galaxy.

While Newton's theory of gravity explains most large-scale movements in the cosmos, Milgrom's Modified Newtonian Dynamics suggests that a force acts differently when it is weak, such as at the edge of a galaxy.

Advocates of the theory say it predicts the rotation of galaxies and the speed of the stars better than Newton's theory.

But we still don't know whether we will ever discover dark matter or prove Milgrom's Modified Newtonian Dynamics. What we do know is that our understanding of the universe is far from complete.

Edited by: Zulfikar Abbany

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The 5 biggest scientific breakthroughs of 2022: Fusion energy, ‘life after death’, and more

Scientific Breakthroughs of the Year: 

From a breakthrough in nuclear fission energy technology to pigs being "revived" after their death, here are some of the biggest scientific breakthroughs that happened in 2022.

Written by Sethu Pradeep
New Delhi | Updated: December 17, 2022 

Scientific Discoveries of 2022: The year 2022 bore witness to many impressive scientific breakthroughs including the simulation of a wormhole to an artificial mouse embryo that developed a brain. 

(Image credit: Indian Express)

A major US breakthrough in nuclear fusion technology gave us a glimpse of a future where a renewable, clean and near-limitless source of energy might just be possible. This breakthrough capped off an exciting year for science, which bore witness to many scientific developments that promise to alter the course of humanity and our understanding of the universe. Here, we have put together five of the most significant scientific developments that happened this year.

Fusion energy breakthrough promises future of clean energy

Scientists announced on Tuesday (December 13) that researchers at the Lawrence National Laboratory in California conducted a nuclear fission reaction that produced more energy than what was used to ignite it. This marks a major breakthrough for the field. Nearly all the energy on the planet comes from nuclear fusion energy. Many of the energy sources that we know, from the food we eat to the fossil fuels that we burn, can be traced back to nuclear fission reactions that happen in the Sun. But we are still years, and maybe decades away, from mastering the process ourselves.

The conventional nuclear electric plants that we know and nuclear weapons derive their energy from a nuclear fission process, where the nucleus of an atom, usually Uranium, is split into two different nuclei, generating large amounts of energy.

Also read |Why fusion could be a clean-energy breakthrough

In an almost contrary process, nuclear fusion is when two nuclei fuse together to form a single heavier nucleus. When this happens, the mass of the new heavier nucleus is less than the sum of the individual nuclei combined, meaning that a little bit of mass is lost. E=MC^2, Einstein’s most famous equation, explains how this mass is converted into a large amount of energy.

While both fission and fusion reactions release large amounts of energy, the latter produces substantially more energy than the former. For example, the nuclear fusion of two nuclei of a heavier hydrogen isotope will produce four times as much energy as the fission of a uranium atom.

If nuclear fission energy were to be commercialised, it would offer a clean and renewable source of energy that will help fight climate change, while also not producing the panoply of radioactive waste products that fission energy reactors are known for. The technology still has a long way to go before becoming a viable energy alternative, as fusion reactions currently being tested barely last a few minutes, due to the difficulty in maintaining the conditions required for the reactions to happen.
Large hadron collider gets back into action, producing almost immediate results

After a hiatus of over three years for maintenance and upgrades, the world’s largest particle accelerator, the large hadron collider (LHC), got back into action in April this year. This marked the beginning of the third run of LHC, when scientists will collect data from an unparalleled number of particle collisions happening at unprecedented energy levels.

The LHC did not take long after starting up again to deliver impressive new science. In July this year, CERN (European Organization for Nuclear Research) announced the discovery of three new exotic particles—a new pentaquark and a pair of new tetraquarks— using the particle accelerator.

Also read |“Everyone wants to look for a signal that goes beyond the standard physics model”: Scientist at Large Hadron Collider

“The newly-discovered pentaquark is still a baryon, but with the three quarks, it has an extra pair consisting of a quark and an anti-quark. The two tetraquarks are within the family of mesons, but instead of having pairs of quarks and anti-quarks, it has two pairs of quarks. These states were predicted in the nominal quark model introduced in the sixties, but these states were not found until now,” said Nicola Neri, a senior member of the LHCb (LHC beauty) experiment, to indianexpress.com at the time.

During its third run, the unrivalled number of collisions in LHC will allow physicists from around the world to study the Higgs boson particle in great detail, while also putting the “Standard model of particle physics” through its most rigorous tests yet.

“Baby wormhole” simulated in a quantum computer

Since they were first proposed by Albert Einstein and Nathan Rosen in 1935, wormholes have remained in the realm of speculative science fiction. Wormholes, or Einstein-Rosen bridges, are theoretical structures that can be considered a tunnel with two ends at different points in space-time. This tunnel could be connecting two points at large or small distances, or two different points in time.

Now, scientists have brought wormholes out of the worlds of “Interstellar” and “Star Trek” and have brought it into this world that we live in. Well, sort of. Researchers at the California Institute of Technology (CalTech) created two simulated black holes in a quantum computer and transmitted a message between them, essentially creating a tunnel in space-time.

While the researchers did not create a rupture in space and time in physical space, it appeared a traversable wormhole was formed based on quantum information “teleported” using quantum codes on the quantum computer.

“There’s a difference between something possible in principle and possible in reality. So don’t hold your breath about sending your dog through the wormhole. But you have to start somewhere. And I think it’s exciting that we can get our hands on this at all,” said Fermilab physicist and study co-author Joseph Lykken to Reuters, at the time.

While it may be a long time before we can send a person, or indeed, their dog, through a wormhole, this research still represents an important breakthrough. Scientists have long pursued a better understanding of these wormholes, and the new research will help them make progress towards that goal.

“Reversing death” by reviving pig cells

From the Greek mythological figure Achilles to the Hindu mythological figure Hiranyakashipu, who was killed by Narasimha, the quest for immortality is a tale as old as time. But new research published in the journal Nature this August by Yale scientists plays with that notion of immortality.

The New York Times reported how scientists pumped a custom-made solution called OrganEx into dead pigs’ bodies using a device similar to the heart-lung machines used in hospitals. As the machine began circulating the solution into the cadavers’ veins and arteries, its brain, heart, liver and kidney cells began functioning again. Also, the cadavers never got stiff, unlike typical dead bodies.

Even though the seemingly dead cells seemed revived, the pigs were not conscious. While this experiment was far off from immortality and actually reversing death, it opens up important questions about the scientific division between life and death.

One of the main goals of the researchers is to increase the supply of human organs for transplant in the future by letting doctors obtain viable organs long after a patient has died. They also hope this technology could be used to prevent severe damage to organs like the heart after a major heart attack or the brain after a stroke.

The OrganEx solution used by researchers consisted of nutrients, anti-inflammatory medications, drugs to prevent cell death, and interestingly, nerve blockers—substances that dampen the activity of neurons and prevent the possibility of the pigs regaining consciousness.

But what if the solution did not contain nerve blockers? Would the brains of the pigs be revived, essentially reanimating them from death? Well, these are questions that the researchers are still yet to answer. But any research in this direction will be burdened by many ethical considerations, apart from the scientific challenges.

Synthetic mouse embryo develops a beating heart

In another scientific breakthrough that will have you questioning what life means, the University of Cambridge and Caltech created an artificial embryo without using any sperm or egg cells. The embryo created using mouse stem cells developed a brain, a beating heart, and the foundations for all the other organs in the body, according to the University of Cambridge.

The stem cells are the body’s master cells and can develop into almost any of the many cell types in the body. The researchers mimicked the natural processes that happen at conception and guided three types of stem cells found in early mammalian development till they began interacting. They established a unique environment for their interactions and got the stem cells to talk to each other.

Due to this, the stem cells organised themselves into structures and progressed through developmental stages until the embryos had beating hearts and the foundations of the brain, along with the yolk sac from which embryos get nutrients in the first weeks. Unlike other synthetic embryos developed in the past, the researchers’ embryos reached the point where the entire brain began to develop.

“Our mouse embryo model develops not only a brain, but also a beating heart, all the components that make up the body. It’s unbelievable that we’ve got this far. This has been the dream of our community for years, and a major focus of our work for a decade, and finally we’ve done it,” said Magdalena Zernicka-Goetz, corresponding author of a research article published in the journal Nature.

This research was carried out on mice, but the researchers hope the technology can be used to develop certain human organ types. This research helps them understand the crucial organ development processes that could not be done with real human embryos. The “14-day rule” in the United Kingdom and other countries prevents scientists from studying human embryos in laboratory conditions.

But further investigating this science could potentially lead to a future where individual human organs can be grown in laboratory settings using stem cells, so that they can be transplanted to a human patient.