52 research outputs found
Search for BSM physics using challenging signatures with the ATLAS detector
No full textMany theories beyond the Standard Model (BSM) predict unique signatures which are difficult to reconstruct and for which estimating the background rates is also a challenge. Signatures of new long-lived particles, particles with fractional or multiple value of the charge of the electron or high mass stable charged particles are examples of experimentally demanding signatures. The talk will focus on the most recent results using 13 TeV pp collision data collected by the ATLAS detector
FIPs ATLAS results and prospects
No full textResults on FIPs in ATLAS for the FIPs @ LHCb workshop. Talk invited by the workshop organizatio
Searches for BSM physics using challenging and Long-Lived signatures with that ATLAS detector
No full textSlides for a talk at ICNFP 202
The ATLAS Run-2 Trigger Menu for higher luminosities: Design, Performance and Operational Aspects
No full textThe ATLAS experiment aims at recording about 1 kHz of physics collisions, starting with an LHC design bunch crossing rate of 40 MHz. To reduce the massive background rate while maintaining a high selection efficiency for rare physics events (such as beyond the Standard Model physics), a two-level trigger system is used. Events are selected based on physics signatures such as presence of energetic leptons, photons, jets or large missing energy. The trigger system exploits topological information, as well as multi-variate methods to carry out the necessary physics filtering. In total, the ATLAS online selection consists of thousands of different individual triggers. A trigger menu is a compilation of these triggers which specifies the physics algorithms to be used during data taking and the bandwidth a given trigger is allocated. Trigger menus reflect not only the physics goals of the collaboration for a given run, but also take into consideration the instantaneous luminosity of the LHC and limitations from the ATLAS detector readout and offline processing farm. For the 2017 run, the ATLAS trigger has been enhanced to be able to handle higher instantaneous luminosities (up to 2.0x10^{34}cm^{-2}s^{-1}) and to ensure the selection robustness against higher average multiple interactions per bunch crossing. In this presentation, we describe the design criteria for the trigger menus used for Run 2 at the LHC. We discuss several aspects of the process, from the fine-tuning of the prescales, the validation of the algorithms, and the monitoring tools that ensure the smooth operation of the trigger during data-taking. We also report on the physics performance of a few trigger algorithms
Supersymmetry searches in ATLAS
No full textWeak scale supersymmetry remains one of the best motivated and studied Standard Model extensions. This talk summarises recent ATLAS results for searches for supersymmetric (SUSY) particles. Weak and strong production in both R-Parity conserving and R-Parity violating SUSY scenarios are considered. The searches involved final states including jets, missing transverse momentum, light leptons, taus or photons, as well as long-lived particle signatures
Searches for R-Parity violating SUSY with lepton number violation
No full textThe violation of R-parity allows new signatures to be pursued in the search for supersymmetry at the LHC. This talk presents the latest results from the ATLAS experiment using 20/fb of pp LHC collision data of searches for R-parity violating SUSY scenarios with lepton number violation. The results presented are for dedicated searches for resonances, as well as a systematic analysis of the constraints placed on R-parity violating models with lepton flavour violation by the Run-1 ATLAS searches, including those which were originally developed to target R-parity conserving models
Searches for new physics with unconventional signatures at ATLAS and CMS
No full textSummary of the latest results on searches for BSM with unconventional signatures in ATLAS and CM
The ATLAS Trigger Menu design for higher luminosities in Run 2
No full textThe ATLAS experiment aims at recording about 1 kHz of physics collisions, starting with an LHC design bunch crossing rate of 40 MHz. To reduce the large background rate while maintaining a high selection efficiency for rare physics events (such as beyond the Standard Model physics), a two-level trigger system is used. Events are selected based on physics signatures such as the presence of energetic leptons, photons, jets or large missing energy. The trigger system exploits topological information, as well as multivariate methods to carry out the necessary physics filtering for the many analyses that are pursued by the ATLAS community. In total, the ATLAS online selection consists of nearly two thousand individual triggers. A Trigger Menu is the compilation of these triggers, it specifies the physics selection algorithms to be used during data taking and the rate and bandwidth a given trigger is allocated. Trigger menus must reflect the physics goals of the collaboration for a given run, but also take into consideration the instantaneous luminosity of the LHC and limitations from the ATLAS detector readout and offline processing farm. For the 2017 run, the ATLAS trigger has been enhanced to be able to handle higher instantaneous luminosities (up to 2.0x10^{34}cm^{-2}s^{-1}) and to ensure the selection robustness against higher average multiple interactions per bunch crossing. In this presentation we describe the design criteria for the trigger menu for Run 2. We discuss several aspects of the process of planning the trigger menu, starting from how ATLAS physics goals and the need for detector performance measurements enter the menu design, and how rate, bandwidth, and CPU constraints are folded in during the compilation of the menu. We present the tools that allow us to predict and optimize the trigger rates and CPU consumption for the anticipated LHC luminosities. We outline the online system that we implemented to monitor deviations from the individual trigger target rates and to quickly react to changing LHC conditions and data taking scenarios. Finally we give a glimpse of the 2017 Trigger Menu, allowing the listener to get a taste of the vast physics program that the trigger is supporting
Searches for Exotic Phenomena at the LHC
No full textSlides for PIC 2021, starting on 14 September in Aachen Material from ATLAS and CM
Searches for ultra long-lived particles with MATHUSLA
No full textWith the current experiments at the particle accelerators, no search strategy will be able to observe the decay of neutral long-lived particles with masses above GeV and lifetimes at the limit set by Big Bang Nucleosynthesis, ∼ 107 − 108 m. The MATHUSLA detector concept (MAssive Timing Hodoscope for Ultra-Stable neutraL pArticles) will be presented. It can be implemented on the surface above ATLAS or CMS detectors in time for the high-luminosity LHC operations, to search for neutral long-lived particles with lifetimes up to the BBN limit. The large area of the detector allows MATHUSLA to make important contributions also to cosmic-ray physics. We will also report on the analysis of data collected by the test stand installed on the surface above the ATLAS detector, the on-going background studies, and plans for the MATHUSLA detector. The observation of neutral long-lived particles at the LHC would reveal physics beyond the Standard Model and could account for the many open issues in our understanding of our universe. Long- lived particle signatures are well motivated and can appear in many theoretical constructs that address the Hierarchy Problem, Dark Matter, Neutrino Masses and the Baryon Asymmetry of the Universe
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