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Testing CPT symmetry via precision mass measurements of multi-strange baryons in ALICE
No full textIn these proceedings, the measurements of the Ξ−, Ξ¯+, Ω¯, Ω¯+ masses and the mass differences between particle and anti-particle have been measured in pp collisions collected by the ALICE Collaboration during LHC Run 2. The results significantly improve the precision from previous experiments, thus allowing direct tests of CPT symmetry to an unprecedented level of precision in the multi-strange baryon sector.In these proceedings, the measurements of the , , , masses and the mass differences between particle and anti-particle have been measured in pp collisions collected by the ALICE Collaboration during LHC Run 2. The results significantly improve the precision from previous experiments, thus allowing direct tests of CPT symmetry to an unprecedented level of precision in the multi-strange baryon sector
Search for a very low mass diphoton resonance using 2018 data
No full textThe existence of a new spin-zero particle with a mass lower than the electroweak scale is predicted by several theoretical models, and searches for resonant production of photon pairs at the LHC are able to probe these models. We present a search for a narrow resonance produced through gluon-fusion that decays into a pair of photons in the invariant mass range between 10 and 70 GeV, using a proton-proton collision data set from the CMS experiment. This data set was recorded in 2018 at a center-of-mass energy of TeV and corresponds to an integrated luminosity of 54.4 fb. No significant excess above the expected background is observed. Upper limits are set on the cross section times branching fraction for diphoton resonance production via gluon-fusion. An interpretation of these limits in the context of an axion-like-particle effective field theory model is also provided
Enhancing software-hardware co-design for HEP by low-overhead profiling of single- and multi-threaded programs on diverse architectures with Adaptyst
No full textGiven the recent technological trends and novel computing paradigms spanning both software and hardware, physicists and software developers can no longer just rely on computers becoming faster to meet the ever-increasing computing demands of their research. Adapting systems to the new environment may be difficult though, especially in case of large and complex applications. Therefore, we introduce Adaptyst (formerly AdaptivePerf): an open-source and architecture-agnostic tool aiming for making these computational and procurement challenges easier to address. At the moment, Adaptyst profiles on- and off-CPU activity of codes, traces all threads and processes spawned by them, and analyses low-level software-hardware interactions to the extent supported by hardware. The tool addresses the main shortcomings of Linux "perf" and has been successfully tested on x86-64, arm64, and RISC-V instruction set architectures. Adaptyst is planned to be evolved towards a software-hardware co-design framework which scales from embedded to high-performance computing in both legacy and new applications and takes into account a bigger picture than merely choosing between CPUs and GPUs. Our paper describes the current development of the project and its roadmap
Classification of Electron and Muon Neutrino Events for the ESSSB Near Water Cherenkov Detector using Graph Neural Networks
No full textIn the effort to obtain a precise measurement of leptonic CP-violation with the ESSSB experiment, accurate and fast reconstruction of detector events plays a pivotal role. In this work, we examine the possibility of replacing the currently proposed likelihood-based reconstruction method with an approach based on Graph Neural Networks (GNNs). As the likelihood-based reconstruction method is reasonably accurate but computationally expensive, one of the benefits of a Machine Learning (ML) based method is enabling fast event reconstruction in the detector development phase, allowing for easier investigation of the effects of changes to the detector design. Focusing on classification of flavour and interaction type in muon and electron events and muon- and electron neutrino interaction events, we demonstrate that the GNN reconstructs events with greater accuracy than the likelihood method for events with greater complexity, and with increased speed for all events. Additionally, we investigate the key factors impacting reconstruction performance, and demonstrate how separation of events by pion production using another GNN classifier can benefit flavour classification
Les Dieux et le Père Noël : vers une solution quantique
No full textLes Dieux et le Père Noël : vers une solution quantique
Comédie quantique
« Des chercheurs qui cherchent, on peut en trouver. Des chercheurs qui trouvent des choses, on en cherche ! Vous trouvez que c’est drôle ? Eh bien, non ! Un chercheur qui a trouvé quelque chose, c’est d’abord et avant tout un chercheur qui n’a plus de travail. Il se retrouve au chômage, bien sûr, parce qu’il a trouvé quelque chose ! En plus, il faut voir ce qui a été découvert... Vous croyez que le gars qui a inventé la bombe atomique est heureux ? Je ne suis pas un “trouveur”, je suis un chercheur !
Franchement, est-ce qu’on peut faire preuve d’ouverture d’esprit sans avoir à se prendre la tête avec l’obligation de résultat ? »
Le comédien Luc Chareyron, trublion mi-savant mi-poète, s’interroge sur le surnaturel et la pensée rationnelle. Que savons-nous ? Qui devons-nous croire ? Dans son spectacle, le comédien nous propose son interprétation personnelle de la mécanique quantique, nous expliquant par exemple comment le Père Noël parvient à livrer plus de 300 000 tonnes de cadeaux en une nuit ! La superposition quantique peut-elle expliquer cet incroyable tour de force ?
Informations pratiques
Horaires : Ouverture des portes à 19:30, début de l'événement à 20:00. Durée: 1h30
Lieu : Portail de la science, Auditorium Sergio Marchionne
Langue : français
Inscription : événement gratuit, inscription obligatoire via ce lien.
Petite restauration
Avant le début de l’événement, le Big Bang Café sera ouvert et vous accueillera jusqu'à 20h00. Profitez d’une petite restauration avec sandwichs et boissons pour bien démarrer la soirée.
'Les Dieux et le Père Noël : vers une solution quantique'
Quantum Comedy
‘Researchers who seek, we can find. Researchers who find things, we look for them! Do you think that's funny? Well, it's not! A researcher who has found something is first and foremost a researcher who no longer has a job. He's unemployed, of course, because he's found something! What's more, you have to see what you find... Do you think the guy who found the atomic bomb is happy? I'm not a ‘finder’, I'm a researcher!
Frankly, can we still open our minds without banging our heads against the obligation to achieve results?'
As a scientific-poetic troublemaker, comedian Luc Chareyron asks questions about supernatural vs rational thinking. What do we know? Who should we believe? He does so through his own interpretation of quantum mechanics, such as his explanation about how Santa can deliver over 300,000 tonnes of presents in one night! Can quantum superposition explain this incredible achievement?
Practical information
Time: Doors opening at 19.30, event starts at 20.00. Duration: 1h30.
Location: CERN Science Gateway, Auditorium Sergio Marchionne
Language: French
Registration: Free of charge, mandatory registration by clicking here.
Refreshments
Prior to the event, the Big Bang café will stay open until 20.00. Enjoy a light meal with sandwiches and drinks for a great start to the evening.
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HL-LHC projections for searches for new resonances
No full textSensitivity estimates to search for new spin-0 resonances at HL-LHC are presented in the decay channels to two Z bosons or two top quarks. Using searches conducted with Run 2 data collected by the CMS detector from 2016 to 2018 at a center-of-mass energy of 13 TeV, results are projected to integrated luminosities of 4 and 6 , at a center-of-mass energy of 14 TeV, corresponding to the sum of data collected by ATLAS and CMS detectors. Expected exclusion limits at 95\% confidence level on cross sections or coupling strengths are computed as a function of the resonance mass for both decay channels, under different assumptions on decay width and production mechanisms
High-Precision Measurement of the B0 Meson Effective Lifetime in the J/psi K*0 Decay Channel
No full textA new high-precision measurement of the B0 effective lifetime in the B0 -> J/psi K*0 decay channel is presented, using 140 fb-1 of 13 TeV pp collision data measured with ATLAS. Results for the average decay width, Gamma_d, and the width ratio Gamma_d/Gamma_s are also reported. This measurement provides the most precise result of the effective lifetime of the B0-meson to date. The measured quantities are in agreement with theoretical predictions and with measurements by other experiments
Observation of charge-parity symmetry breaking in baryon decays
No full textThe Standard Model of particle physics, the theory of particles and interactions at the smallest scale, predicts that matter and antimatter interact differently due to violation of the combined symmetry of charge conjugation () and parity (). Charge conjugation transforms particles into their antimatter particles, while the parity transformation inverts spatial coordinates. This prediction applies to both mesons, which consist of a quark and an antiquark, and baryons, which are composed of three quarks. However, despite having been discovered in various meson decays, violation has yet to be observed in baryons, the type of matter that makes up the observable Universe. This article reports a study of the decay of the beauty baryon to the final state and its -conjugated process, using data collected by the LHCb (Large Hadron Collider beauty) experiment at CERN. The results reveal significant asymmetries between the decay rates of the baryon and its -conjugated antibaryon, marking the first observation of violation in baryon decays, thus demonstrating the different behaviour of baryons and antibaryons. In the Standard Model, violation arises from the Cabibbo-Kobayashi-Maskawa mechanism, while new forces or particles beyond the Standard Model could provide additional contributions. This discovery opens a new path to search for physics beyond the Standard Model.The Standard Model of particle physics, the theory of particles and interactions at the smallest scale, predicts that matter and antimatter interact differently due to violation of the combined symmetry of charge conjugation () and parity (). Charge conjugation transforms particles into their antimatter particles, while the parity transformation inverts spatial coordinates. This prediction applies to both mesons, which consist of a quark and an antiquark, and baryons, which are composed of three quarks. However, despite having been discovered in various meson decays, violation has yet to be observed in baryons, the type of matter that makes up the observable Universe. This article reports a study of the decay of the beauty baryon to the final state and its -conjugated process, using data collected by the LHCb (Large Hadron Collider beauty) experiment at CERN. The results reveal significant asymmetries between the decay rates of the baryon and its -conjugated antibaryon, marking the first observation of violation in baryon decays, thus demonstrating the different behaviour of baryons and antibaryons. In the Standard Model, violation arises from the Cabibbo-Kobayashi-Maskawa mechanism, while new forces or particles beyond the Standard Model could provide additional contributions. This discovery opens a new path to search for physics beyond the Standard Model