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How large could CP violation in meson mixing be? Implications for baryogenesis and future searches
No full textIt is well-known that CP violation is one of the necessary ingredients to generate the observed matter-antimatter asymmetry of the Universe. Neutral mesons naturally exhibit CP violating oscillations, such that the amount of CP violation in their mixing can be directly related to the baryon asymmetry through the -mesogenesis mechanism. With this in mind, it is interesting to analyze the extent to which CP is violated in meson mixing within different scenarios beyond the Standard Model. In particular, we consider: (i) the effects of heavy new physics in the mass mixing following a model-independent approach, (ii) the implications of CKM unitarity deviations with the inclusion of vector-like quarks, and (iii) the role of new contributions to the decay width mixing. The available parameter space for the relevant CP asymmetries is presented, studying their compatibility with the -mesogenesis framework and comparing it with the expected experimental sensitivity for these quantities at LHCb and Belle II
Search for dark matter with mono-Higgs signature (YSF)
No full textThe discovery of the Standard Model Higgs boson extended the possibility to search for dark matter in the mono-Higgs final state. A search for dark matter produced in association with a Higgs boson decaying to a pair of bottom quarks is presented, with final state signature of b-tagged jets recoiling against large missing transverse energy. The data were recorded from proton-proton collisions at a center of mass energy of 13 TeV with the CMS experiment at CERN's Large Hadron Collider, corresponding to an integrated luminosity of 101.3~. The analysis is performed in exclusive channels targeting both boosted and resolved b quark pair topologies, covering a wide range of Higgs boson transverse momentum. The data are observed to agree with the SM predictions and limits on possible new physics are set in the framework of simplified benchmark models, 2HDM+a and Baryonic-
Observation of orbitally excited states at LHCb
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As the only meson family composed of two heavy quarks with different flavors, the meson serves as a unique platform to probe the non-perturbative behavior of Quantum Chromodynamics (QCD), thereby improving our understanding of the strong interaction. The experimental exploration in spectroscopy remains limited due to the low production cross-section of mesons. So far, besides the ground state, only the second S-wave excited states have been observed. The high production rates of mesons at the LHC and the excellent performance of the LHCb detector establish the LHCb experiment as an ideal laboratory for studies. In this talk, the first observation of orbitally excited states by the LHCb experiment will be presented, along with studies of the newly observed states.
Refreshments will be served at 10h30</p
Searches for Beyond Standard Model Higgs boson decays (including low mass resonances) in the ATLAS Experiment at CERN
No full textThe discovery of the Higgs boson with the mass of about 125 GeV completed the particle content predicted by the Standard Model. Even though this model is well established and consistent with many measurements, it is not capable of explaining some observations by itself. Many extensions of the Standard Model addressing such shortcomings introduce beyond-the-Standard-Model couplings to the Higgs boson. In this talk, the latest searches in the Higgs sector are reported, with emphasis on the results obtained with the full LHC Run 2 dataset at 13 TeV and including a series of searches for low-mass resonances in merged or boosted topologies
Long-Lived and Dark Matter Searches at ATLAS and CMS
No full textMany theories beyond the Standard Model (BSM) have been proposed to address several of the Standard Model shortcomings, such as the origin of dark matter and neutrino masses, the fine-tuning of the Higgs Boson mass, or the observed pattern of masses and mixing angles in the quark and lepton sectors. Many of these BSM extensions predict new particles or interactions directly accessible at the LHC. This talk will present highlights on recent searches for new physics in the Long-Lived and Dark Matter sectors, using pp data collected by the ATLAS and CMS detectors at the LHC
Search for new physics in jet scaling patterns of multilepton events at 13 TeV
No full textA first search for beyond the standard model physics in jet scaling patterns of multilepton events is presented, using a data sample corresponding to an integrated luminosity of 138 fb of 13 TeV proton-proton collisions recorded by the CMS detector at the LHC. The search uses observed jet multiplicity distributions in one-, two-, and four-lepton events to explore possible enhancements in jet production rate in three-lepton events with and without bottom quarks. The data are found to be consistent with the standard model expectation. The results are interpreted in terms of supersymmetric production of electroweak chargino-neutralino superpartners with cascade decays terminating in prompt hadronic -parity violating interactions.A first search for beyond the standard model physics in jet multiplicity patterns of multilepton events is presented, using a data sample corresponding to an integrated luminosity of 138 fb-1 of 13 TeV proton-proton collisions recorded by the CMS detector at the LHC. The search uses observed jet multiplicity distributions in one-, two-, and four-lepton events to explore possible enhancements in jet production rate in three-lepton events with and without bottom quarks. The data are found to be consistent with the standard model expectation. The results are interpreted in terms of supersymmetric production of electroweak chargino-neutralino superpartners with cascade decays terminating in prompt hadronic R-parity violating interactions.A first search for beyond the standard model physics in jet multiplicity patterns of multilepton events is presented, using a data sample corresponding to an integrated luminosity of 138 fb of 13 TeV proton-proton collisions recorded by the CMS detector at the LHC. The search uses observed jet multiplicity distributions in one-, two-, and four-lepton events to explore possible enhancements in jet production rate in three-lepton events with and without bottom quarks. The data are found to be consistent with the standard model expectation. The results are interpreted in terms of supersymmetric production of electroweak chargino-neutralino superpartners with cascade decays terminating in prompt hadronic -parity violating interactions
Visit by Dr Stephen K. Streiffer, Director, Oak Ridge National Laboratory, USA
No full textVisit by Dr Stephen K. Streiffer, Director, Oak Ridge National Laboratory, United States of Americ
Machine learning in top quark physics at ATLAS and CMS
No full textThis note presents an overview of machine-learning-based techniques used in the study of the top quark. The research community has developed a diverse set of ideas and tools, including algorithms for the efficient reconstruction of recorded collision events and innovative methods for statistical inference. Recent applications by the ATLAS and CMS collaborations are also highlighted