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Institute of Nuclear Physics and Engineering from National Research Nuclear University “MEPhI”  invites experts and young scientists working in experimental and theoretical areas of particle and astroparticle physics to participate in 3rd International Conference on Particle Physics and Astrophysics (from the 2nd to 5th October 2017). The conference will be held in Milan Hotel.

The scientific program of the conference includes plenary and section talks on nuclear physics, heavy-ion physics, high energy physics, astroparticle and neutrino physics as well as gravity and cosmology. Most recent results from the modern experiments in these areas and advanced detector technology development will be presented and discussed. A special session of the conference will be devoted to posters.

Leading scientists from all over the world were invited to give their talks:

  • D. Froidevaux (CERN, Geneva, Switzerland)
  • C. Giunti (INFN, Turin, Italy)
  • A. D. Dolgov  (Novosibirsk & Ferrara Univ., NRC KI ITEP, Moscow, Russia)
  • S. V. Ivanov (NRC KI IHEP, Protvino, Russia)
  • D.I. Kazakov (JINR, Dubna,Russia)
  • Yu. Yu. Kovalev (LPI ,Moscow, Russia)
  • R. V. Mizyuk (LPI, Moscow, Russia)
  • V. F. Obraztsov (NRC KI IHEP, Protvino, Russia)
  • Yu. Ts. Oganessian (JINR, Dubna,Russia)
  • A. A. Ogloblin (NRC KI, Moscow, Russia)
  • G. Passaleva (INFN, Florence, Italy)
  • G. Ranucci (INFN, Milan, Italy)
  • B. Yu. Sharkov (NRC KI ITEP, Moscow, Russia)
  • L. Shchutska (ETH, Zurich, Switzerland)
  • D. Wark (University of Oxford, Oxford, Great Britain)

Proceedings of the conference will be published in a peer-reviewed journal. Please visit: http://indico.cfr.mephi.ru/e/ICPPA2017 to find the first bulletin and to register.

The deadline for registration is August 21, 2017.

If you have any questions, please contact organizing committee by e-mail:  icppa2017@mephi.ru

19.06.2017

http://atlas.cern/updates/atlas-news/atlas-highlights-moriond

12.04.2017

International group of physicists, which includes MEPhI scientists, for the first time managed to observe Z-boson production with two associated photons with later Z decay to electrons, muons or neutrino at ATLAS experiment at Large Hadron Collider (LHC) in CERN.
     Observation of this extremely rare physics process, predicted by theory in 1960-s, has become another proof of the Standard Model (SM), said one of ATLAS experiment members and engineer of  Department of Elementary Particles Physics (MEPhI) Dimitrii Krasnopevtsev.
     Such rare process as Z-boson production with two associated photons is an important test of electro-weak sector of SM theory with the highest precision. At the moment our group has not found any deviations from theoretical predictions; in other words, we have once again confirmed Standard Model”, - he explained.
     Scientists studied Z-boson production with one or two associated photons. It required precise measurements of the process possibility along with kinematic parameters of registered particles. 
“Precision improvements are important to test Standard Model predictions. In our study we put limits on “exotic” theories, which can contribute to the final state of Z production with photons. 
     So-called intermediate bosons W± and Z were discovered in CERN in 1983. W- and Z-bosons were produced in proton-antiproton collisions with energies of 540 GeV. All three of these particles are very short-lived, with a half-life of about 3×10−25 s and can be detected only by their decay products. 
     Standard Model is a general theory describing interactions and particles, at the best level known by physicists at the moment. One of the most important tasks in modern high energy physics is the experimental test of its predictions. Nowadays scientists have not found any deviations from this theory, but there are large uncertainties in some measurements and some processes are so rare, that there are still possibilities to observe new phenomena.
     Scientists from MEPhI added that such triboson production studies (Z-boson with two photons) show that energy and integrated luminosity at Large Hadron Collider allow us to start the most precision measurements of SM with very rare processes.
     Scientists from MEPhI, Argonne National Laboratory of the US Department of Energy, Duke University of the US and South methodical University took part in the work.
                                                                        

Based on RIA Novosti material

 

27.06.2016

International cooperation is extremely important in high energy science. Only a large collaboration of scientists and universities can create world-wide experiment – like Large Hadron Collider (LHC). National Research Nuclear University «MEPhI» actively supports international cooperations by sending its students all over the world.

In 2015, 4 master and graduate students from department of «Experimental methods of nuclear physics» №11 in the Center of Fundamental Research (CFR) spent several months working on the most important experiments of high energy physics. Our press center asked them to tell their exciting stories.

Sergey Fedotov, graduate:

In 2015 I had an opportunity to participate in activities connected with NA62 experiment in the European Organization for Nuclear Research (CERN) during three months. My work was funded by NRNU MEPhI.

The main goal of NA62 experiment is to study a rare kaon decay (K + → π + νν). Cross section measurements of this process allow to test the theoretical predictions of the Standard Model (SM). Deviations from the theory may indicate the existence of physics beyond the SM. This decay is strongly suppressed, so studies require a large amount of data. Previous results included high errors. We expect to achieve uncertainty of 10% with new NA62 measurements.

My task was connected with developing and testing one of the main part of NA62 detector: Charged-particle hodoscope NewCHOD. I’ve also participated in detector monitoring (so called shifts) during the NA62 operation. It is a time when all detectors are collecting statistics for future physics analysis. My master's thesis was based on my studies during stay in CERN.

During these three months I successfully used the knowledge obtained in NRNU MEPhI and enriched it with the experience of my colleagues in CERN.  

My trip had gone very quickly leaving only pleasant memories. I express my deep gratitude to MEPhI, department №11 «Experimental methods of nuclear physics» and in particular to my supervisor prof. Kudenko Yuri Grigorievich for all these positive emotions and invaluable experience.

Sergey (third on the left) with NA62 collaboration members.

Alina Kleimenova, student:

When I was at school, I was listening to the news on the radio from the European Organization for Nuclear Research and thinking that it should be a pretty interesting place. I have not ever imagined to find myself there.

However, this summer I had the opportunity to work for the NA62 experiment. My scientific work associated with this experiment began from work with INR RAS research group. It was silicon photomultipliers testing for NewCHOD detector. Тew horizons were opened once I arrived to Geneva. Firstly, I was lucky enough to take part in detector monitoring shifts – it made possible to look at the work of a large experiment from the inside. And secondly, I started analyzing the data obtained in these sessions. My new colleagues provided me a lot of support in my studies.

During my internship I was able to learn how to use available software to write my own programs to evaluate the performance of some detectors and to get skills in processes modelling in the scintillator (NewCHOD is a scintillation hodoscope). I also started working on my master's thesis which is dedicated to search for heavy neutrinos in the kaons decay.

Looking back, I can say that it was great 90 days filled with new interesting acquaintances, excursions, hiking and of course experimental physics. I am very glad I was able to be in such a beautiful place to work for so long.

As it turned out, this was not my last visit to CERN. I took part in collaboration meeting in February, where the next data collecting period and analysis of already accumulated data were discussed.

Maria Antonova, student:

My scientific work is related to the study of muon range detector SMRD characteristics. It based on INR RAS platform, supervising by prof. Kudenko Yuri Grigorievich (in MEPhI) and senior scientist Izmailov Alexander Olegovich (in RAS HEP). SMRD detector is array of scintillation counters placed in ND280 detector magnet of the long-baseline T2K experiment. Its main purpose is to study neutrino oscillations parameters.

This year I participated  in the regular collaboration meeting which took place in  Tokai, Japan. Meetings are held 4 times a year, but this time it was dedicated to the celebration in honor of the "Breakthrough Prize" laureate Koichiro Nishikawa, who made a great contribution to neutrino physics research.

A journey to the T2K meeting was a great opportunity to talk personally with people involved in the experiment and to learn details of their research. Such meetings incredibly encourage to work in experimental physics.

T2K collaboration and Breakthrough Prize laureate Koichiro Nishikawa

Tatiana Ovsiannikova, graduate student:

In the second half of 2015 assembling works for pilot detector of WAGASCI experiment (Water-Grid-Scintillator-Detector) have been started. One of the physics goals of WAGASCI experiment is the measurement of the cross sections ratio between neutrino to water and neutrino to hydrocarbon. It will allow to reduce systematic errors related to the target substance in the far and the near detector of the neutrino accelerator experiment with long-baseline T2K. The second goal is charged current neutrino interaction channels measurements.

WAGASCI pilot detector is a water-filled unit (one of four) of WAGASCI detector central target. One of the INGRID iron-scintillation detector modules will be used as the muon range detector. It will work on the on-axis beam of the J-PARC accelerator.

In October 2015, as a graduate student of the department «Experimental methods of nuclear physics» of NRNU MEPhI CFR I took part in the WAGASCI detector prototype construction in Tokai, Japan, where the accelerator facility J-PARC and the near detector ND280 of T2K experiment are based.

At the moment prototype detector construction is near the completion and physics operation will start in March. Each member of our group has been involved in the manufacturing process of scintillation counters, assembly and various tests. My scientific work is related to the computer simulation, so it was very interesting to construct the real detector with my own hands.

Collaboration members at work (Tatiana on the left)

 

24.03.2016

Geneva, 14 July 2015. Today, the LHCb experiment at CERN’s Large Hadron Collider has reported the discovery of a class of particles known as pentaquarks. The collaboration has submitted a paper reporting these findings to the journal Physical Review Letters.

“The pentaquark is not just any new particle,” said LHCb spokesperson Guy Wilkinson. It represents a way to aggregate quarks, namely the fundamental constituents of ordinary protons and neutrons, in a pattern that has never been observed before in over fifty years of experimental searches. Studying its properties may allow us to understand better how ordinary matter, the protons and neutrons from which we’re all made, is constituted.”

Our understanding of the structure of matter was revolutionized in 1964 when American physicist, Murray Gell-Mann, proposed that a category of particles known as baryons, which includes protons and neutrons, are comprised of three fractionally charged objects called quarks, and that another category, mesons, are formed of quark-antiquark pairs. Gell-Mann was awarded the Nobel Prize in physics for this work in 1969. This quark model also allows the existence of other quark composite states, such as pentaquarks composed of four quarks and an antiquark. Until now, however, no conclusive evidence for pentaquarks had been seen.

LHCb researchers looked for pentaquark states by examining the decay of a baryon known as Λb (Lambda b) into three other particles, a J/ψ- (J-psi), a proton and a charged kaon. Studying the spectrum of masses of the J/ψ and the proton revealed that intermediate states were sometimes involved in their production. These have been named Pc(4450)+ and Pc(4380)+, the former being clearly visible as a peak in the data, with the latter being required to describe the data fully.

“Benefitting from the large data set provided by the LHC, and the excellent precision of our detector, we have examined all possibilities for these signals, and conclude that they can only be explained by pentaquark states”, says LHCb physicist Tomasz Skwarnicki of Syracuse University.

"More precisely the states must be formed of two up quarks, one down quark, one charm quark and one anti-charm quark.”

Earlier experiments that have searched for pentaquarks have proved inconclusive. Where the LHCb experiment differs is that it has been able to look for pentaquarks from many perspectives, with all pointing to the same conclusion. It’s as if the previous searches were looking for silhouettes in the dark, whereas LHCb conducted the search with the lights on, and from all angles. The next step in the analysis will be to study how the quarks are bound together within the pentaquarks.

 “The quarks could be tightly bound,” said LHCb physicist Liming Zhang of Tsinghua University, “or they could be loosely bound in a sort of meson-baryon molecule, in which the meson and baryon feel a residual strong force similar to the one binding protons and neutrons to form nuclei.”

More studies will be needed to distinguish between these possibilities, and to see what else pentaquarks can teach us. The new data that LHCb will collect in LHC run 2 will allow progress to be made on these questions.

Source 

For more information:

See paper on ArXiv(link is external)

More on the LHCb collaboration website

 

 

19.07.2015

At about half past nine CET this morning, for the first time since the Large Hadron Collider (LHC) started up after two years of maintenance and repairs, the accelerator delivered proton-proton collisions to the LHC experiments ALICEATLASCMS andLHCb at an energy of 450 gigaelectronvolts (GeV) per beam.

Two beams of protons at 450 GeV collide in the the CMS detector for a total collision energy of 900 GeV. The LHC experiments are using these collisions to tune and align their detectors (Image: CMS/CERN)

At about half past nine CET this morning, for the first time since the Large Hadron Collider (LHC) started up after two years of maintenance and repairs, the accelerator delivered proton-proton collisions to the LHC experiments ALICEATLASCMS andLHCb at an energy of 450 gigaelectronvolts (GeV) per beam.

These collisions, which take place with each beam at the so-called injection energy, that is, the energy at which proton beams are injected into the LHC from the Super Proton Synchrotron, enable the LHC experiments to tune their detectors. This process is also an important step towards readying the accelerator to deliver beams at 6.5 teraelectronvolts (TeV) for collisions at 13 TeV.

Each low-energy collision sends showers of particles flying through an experiment's many layers. The experimental teams can use this data to check their subdetectors and ensure they fire in the correct place at the precise instant that a particle passes. Reconstructing flight paths of the particles from many parts of the detector at once helps the experiments to check the alignment and synchronization of various subdetector elements.

Proton beams collide for a total energy of 900 GeV in the ATLAS detector on the LHC (Image: ATLAS/CERN)

So just as the LHC team tests each component, system, and algorithm one after the other, the experiments go through checklists that confirm that everything is fully functional and no mistakes, bugs or failures are present when collisions are delivered at 13 TeV.

Meanwhile the LHC Operations team is halfway through its eight weeks of scheduled beam commissioning, during which the accelerator's many subsystems are checked to ensure that beams will circulate stably and in the correct orbit. Sensors and collimators around the accelerator's full 27 kilometres send information to the CERN Control Centre, from where the operators can remotely adjust the beam by fine-tuning the positions and field strengths of hundreds of electromagnets.

Proton-proton collision at 900 GeV as determined by the inner silicon trackers in the ALICE detector (Image: ALICE/CERN)

Though the first beam at 6.5 TeV circulated successfully in the LHC last month, there are many more steps before the accelerator will deliver high-energy collisions for physics to the LHC experiments. Well before the full physics programme begins, the LHC operations team will collide beams at 13 TeV to check the beam orbit, quality and stability. 

Proton-proton collision at 900 GeV in the LHCb detector (Image: LHCb/CERN)

from http://home.web.cern.ch/about/updates/2015/05/low-energy-collisions-tune-lhc-experiments

06.05.2015

On Sunday proton beams circulated in the Large Hadron Collider (LHC) for the first time after a 2-year period of maintenance and upgrades to the machine. From the CERN Control Centre, LHC operators and systems experts kept the beams at their injection energy of 450 gigaelectronvolts (GeV), far below the target energy of 6.5 teraelectronvolts (TeV) per beam. Now the operators are testing the accelerator's subsystems and optimizing key beam parameters in preparation for increasing the beam intensity and ramping up the energy.

LHC operators will spend the coming weeks testing and checking all of the accelerator's many subsystems from the CERN Control Centre (Image: Maximilien Brice/CERN)

On Sunday proton beams circulated in the Large Hadron Collider (LHC) for the first time after a 2-year period of maintenance and upgrades to the machine. From the CERN Control Centre, LHC operators and systems experts kept the beams at their injection energy of 450 gigaelectronvolts (GeV), far below the target energy of 6.5 teraelectronvolts (TeV) per beam. Now the operators are testing the accelerator's subsystems and optimizing key beam parameters in preparation for increasing the beam intensity and ramping up the energy.

Only when the machine is sufficiently tuned – and the team declares "Stable Beams" with the beams in collision at the new energy of 6.5 TeV per beam – will the physics data taking begin. This work will take many weeks.

"Beams at injection energy are a useful way of checking that all is running as it should," says LHC operator Ronaldus SuykerBuyk. "For example, we use these low-intensity beams to make sure that our beam-diagnostic equipment is working properly and is well calibrated.”

The team will spend most of the time from now until collisions checking and rechecking a whole wealth of subsystems on the LHC. For example, the Machine Protection subsystem ensures that the LHC is protected from its own beams. It includes the beam dump, beam interlock system, collimators, and beam-energy tracking devices. 'Loss maps' tell the team where the beam is losing particles along the ring. Then there's Beam Instrumentation, which includes position monitors, beam-loss monitors and synchrotron-light monitors among other devices. Not to mention the radiofrequency, vacuum, beam-optics and injection systems, which all need to be tested and double-checked over the coming weeks.

A wealth of subsystems monitor the quality of beams in the LHC (Image: Maximilien Brice/CERN)

Despite the LHC's complexity, increasing the beam energy is a simple enough process: ramp up the current in the magnets and allow the radiofrequencysystem to increase the energy of the beams. The current in all the magnets (and hence the magnetic field seen by the beam) is carefully increased as the beam energy rises. The main dipoles provide the necessary centripetal force to bend the beams around the ring. Other magnets such as the quadrupoles have to carefully track along with the increasing dipole field.

"The machine is behaving as expected at 450 GeV," says Mike Lamont of the LHC operations team. "We are now circulating a single bunch of protons, and using it to test our many subsystems. The bunch currently contains about 5 billion protons. When the LHC is ready, we will increase this number to the nominal bunch population of about 120 billion protons per bunch, and focus on fine-tuning the machine for collisions."

For now the team is taking a softly, softly approach, planning on injecting only three bunches of protons at nominal intensity for the first collision attempts, which are expected in the coming weeks. 

from http://home.web.cern.ch/about/updates/2015/04/lhc-preparations-collisions-13-tev

06.05.2015

After two years of intense maintenance and consolidation, and several months of preparation for restart, the Large Hadron Collider (LHC), the most powerful particle accelerator in the world, is back in operation. Today at 10.41am, a proton beam was back in the 27-kilometer ring, followed at 12.27pm by a second beam rotating in the opposite direction. These beams circulated at their injection energy of 450 GeV. Over the coming days, operators will check all systems before increasing energy of the beams.

"Operating accelerators for the benefit of the physics community is what CERN1’s here for,” said CERN Director-General Rolf Heuer. "Today, CERN’s heart beats once more to the rhythm of the LHC.”  

"The return of beams to the LHC rewards a lot of intense, hard work from many teams of people," said Head of CERN’s Beam Department, Paul Collier. "It’s very satisfying for our operators to be back in the driver’s seat, with what’s effectively a new accelerator to bring on-stream, carefully, step by step.”

The technical stop of the LHC was a Herculean task. Some 10,000 electrical interconnections between the magnets were consolidated. Magnet protection systems were added, while cryogenic, vacuum and electronics were improved and strengthened. Furthermore, the beams will be set up in such a way that they will produce more collisions by bunching protons closer together, with the time separating bunches being reduced from 50 nanoseconds to 25 nanoseconds.

"After two years of effort, the LHC is in great shape," said CERN Director for Accelerators and Technology, Frédérick Bordry. "But the most important step is still to come when we increase the energy of the beams to new record levels.”

The LHC is entering its second season of operation. Thanks to the work done in the last two years, it will operate at unprecedented energy - almost double that of season 1 - at 6.5 TeV per beam. With 13 TeV proton-proton collisions expected before summer, the LHC experiments will soon be exploring uncharted territory.

The Brout-Englert-Higgs mechanismdark matterantimatter and quark-gluon plasmaare all on the menu for LHC season 2. After the discovery of the Higgs boson in 2012 by the ATLAS and CMS collaborations, physicists will be putting the Standard Model of particle physics to its most stringent test yet, searching for new physics beyond this well-established theory describing particles and their interactions.

source http://home.web.cern.ch/about/updates/2015/04/proton-beams-are-back-lhc

05.04.2015

The Large Hadron Collider (LHC), the largest and most powerful particle accelerator in the world, has started to get ready for its second three-year run. Cool down of the vast machine has already begun in preparation for research to resume early in 2015 following a long technical stop to prepare the machine for running at almost double the energy of run 1. The last LHC magnet interconnection was closed on 18 June 2014 and one sector of 1/8 of the machine has already been cooled to operating temperature. The accelerator chain that supplies the LHC’s particle beams is currently starting up, with beam in the Proton Synchrotron accelerator last Wednesday for the first time since 2012.

"There is a new buzz about the laboratory and a real sense of anticipation," says CERN Director General Rolf Heuer, - "Much work has been carried out on the LHC over the last 18 months or so, and it’s effectively a new machine, poised to set us on the path to new discoveries."

Over the last 16 months, the LHC has been through a major programme of maintenance and upgrading, along with the rest of CERN’s accelerator complex, some elements of which have been in operation since 1959. Some 10,000 superconducting magnet interconnections of were consolidated in order to prepare the LHC machine for running at its design energy.

"The machine is coming out of a long sleep after undergoing an important surgical operation," says Frédérick Bordry, CERN’s Director for Accelerators and Technology. "We are now going to wake it up very carefully and go through many tests before colliding beams again early next year. The objective for 2015 is to run the physics programme at 13 TeV."

 

Source: CERN

24.06.2014

In a paper published in the journal Nature Physics today, the CMS experiment at CERN reports new results on an important property of the Higgs particle, whose discovery was announced by the ATLAS and CMS experiments on 4 July 2012. The CMS result follows preliminary results from both experiments, which both reported strong evidence for the fermionic decay late in 2013.

The Higgs boson is associated with a mechanism first put forward in 1964 by Robert Brout, François Englert and Peter Higgs to account for the different ranges of two fundamental forces of nature. Now referred to as BEH, this mechanism is postulated to give rise to the masses of all the fundamental particles. In order to test that idea fully, it is necessary to measure the direct decay of the Higgs boson into all kinds of particles.

When the Higgs boson discovery was announced in 2012, it was based on measurements of the decay of the Higgs to other bosons, the carriers of nature’s forces. The results reported by ATLAS and CMS discuss the decay of Higgs bosons directly to fermions, the particles that make up matter.

The measurements from both have given substantial evidence that the Higgs boson decays directly to fermions at a rate consistent with that predicted by the Standard Model of particle physics, the theory that accounts for the fundamental particles of visible matter and the interactions that work between them, giving structure to matter.

"With our on-going analyses, we are really starting to understand the BEH mechanism in depth," says CMS spokesperson Tiziano Camporesi. "So far, it is behaving exactly as predicted by theory."

"These results show the power of the detectors in allowing us to do precision Higgs physics," says ATLAS spokesperson Dave Charlton. "We’re coming close to achieving all we can on the Higgs analysis with run 1 data, and are all looking forward to new data when the LHC restarts in 2015."

Source: CERN

23.06.2014

​In a paper published in the journal Nature Physics today, the CMS experiment at CERN reports new results on an important property of the Higgs particle, whose discovery was announced by the ATLAS and CMS experiments on 4 July 2012. The CMS result follows preliminary results from both experiments, which both reported strong evidence for the fermionic decay late in 2013.

The Higgs boson is associated with a mechanism first put forward in 1964 by Robert Brout, François Englert and Peter Higgs to account for the different ranges of two fundamental forces of nature. Now referred to as BEH, this mechanism is postulated to give rise to the masses of all the fundamental particles. In order to test that idea fully, it is necessary to measure the direct decay of the Higgs boson into all kinds of particles.

When the Higgs boson discovery was announced in 2012, it was based on measurements of the decay of the Higgs to other bosons, the carriers of nature’s forces. The results reported by ATLAS and CMS discuss the decay of Higgs bosons directly to fermions, the particles that make up matter.

The measurements from both have given substantial evidence that the Higgs boson decays directly to fermions at a rate consistent with that predicted by the Standard Model of particle physics, the theory that accounts for the fundamental particles of visible matter and the interactions that work between them, giving structure to matter.

"With our on-going analyses, we are really starting to understand the BEH mechanism in depth," says CMS spokesperson Tiziano Camporesi. "So far, it is behaving exactly as predicted by theory."

"These results show the power of the detectors in allowing us to do precision Higgs physics," says ATLAS spokesperson Dave Charlton. "We’re coming close to achieving all we can on the Higgs analysis with run 1 data, and are all looking forward to new data when the LHC restarts in 2015."

 

Source: CERN

23.06.2014

    The Gran Sasso Science Institute (GSSI) has opened the call for applications to access the PhD program in Astroparticle Physics (academic year 2014/2015). 10 3-year positions (all with fellowship) are available starting from November 1, 2014.
    The PhD program addresses some of the most pressing and fundamental questions of Astroparticle Physics: the origin and the evolution of the universe, the nature of dark matter and dark energy, the study of neutrinos and of the ultimate constituents of matter, the search for gravitational waves, the investigation and explanation of cosmic rays. GSSI operates in close collaboration with the INFN Gran Sasso Underground Laboratory. The PhD title will be released jointly with SISSA.

The application form, deadline June 30, 2014. 

For more information please visit the GSSI web site www.gssi.infn.it
or contact the Institute secretary by email info@gssi.infn.it

22.06.2014

Scientists working on the world’s leading particle collider experiments have joined forces, combined their data and produced the first joint result from Fermilab Tevatron and CERN’s Large Hadron Collider (LHC), past and current holders of the record for most powerful particle collider on Earth. Scientists from the four experiments involved - ATLAS, CDF, CMS and DZero - announced their joint findings on the mass of the top quark today at the Rencontres de Moriond international physics conference in Italy.

Together the four experiments pooled their data analysis power to arrive at a new world’s best value for the mass of the top quark of 173.34 ± 0.76 GeV/c2.

Experiments at the LHC at the CERN laboratory in Geneva, Switzerland and the Tevatron collider at Fermilab near Chicago in Illinois, USA are the only ones that have ever seen top quarks - the heaviest elementary particles ever observed. The top quark’s huge mass (more than 100 times that of the proton) makes it one of the most important tools in the physicists’ quest to understand the nature of the universe.

The new precise value of the top-quark mass will allow scientists to test further the mathematical framework that describes the quantum connections between the top quark, the Higgs particle and the carrier of the electroweak force, the W boson. Theorists will explore how the new, more precise value will change predictions regarding the stability of the Higgs field and its effects on the evolution of the universe. It will also allow scientists to look for inconsistencies in the Standard Model of particle physics - searching for hints of new physics that will lead to a better understanding of the nature of the universe.

 

The joint measurement has been submitted to the electronic arXiv and is available at: http://arxiv.org/abs/1403.4427

Graphic is available at: http://www.interactions.org/cms/?pid=2100&image_no=OT0172

 

Source: CERN

19.03.2014

The Nobel Prize in Physics 2013 was awarded jointly to François Englert and Peter W. Higgs "for the theoretical discovery of a mechanism that contributes to our understanding of the origin of mass of subatomic particles, and which recently was confirmed through the discovery of the predicted fundamental particle, by the ATLAS and CMS experiments at CERN's Large Hadron Collider".

08.10.2013

The EPS High Energy Physics Division announces the winners of its 2013 prizes, which will be awarded at the Europhysics Conference on High-Energy Physics (EPS-HEP 2013), Stockholm (Sweden) 18-24 July 2013 (http://eps-hep2013.eu/):

The 2013 High Energy and Particle Physics Prize, for an outstanding contribution to High Energy Physics, is awarded to the ATLAS and CMS collaborations, "for the discovery of a Higgs boson, as predicted by the Brout-Englert-Higgs mechanism", and to Michel Della Negra, Peter Jenni, and Tejinder Virdee, "for their pioneering and outstanding leadership roles in the making of the ATLAS and CMS experiments".

22.07.2013