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Séminaires
CPPM PhD days 3 : Atlas
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Europe/Paris
Amphithéâtre (CPPM)
Amphithéâtre
CPPM
Description
9:30 - 9:45 Overview of the ATLAS activities (Laurent Vacavant)
9:45 - 11:00 PhD Student présentation
SUSY Search Using the Two Same Sign Leptons Channel.
Alstaty Mahmoud
SuperSymmetry (SUSY) is one of the leading theories beyond the Standard Model, which predicts the existence of new particles acting as partners to the known Standard Model particles. The 2 same-sign or three leptons SUSY analysis is one of many analyses that search for SUSY particles, such as the sbottom, gluino and the neutralino. The results of this analysis are presented with 13 TeV, 13.3 fb -1. A study of the signal region optimization for SUSY simplified models is discussed. As part of the fake-lepton background estimation in this analysis, measurements of the real lepton efficiency are also discussed.
ttH(H->bb) measurement with the ATLAS detector at LHC
Calvet Thomas
The associated production of a Higgs boson with top quarks is the only way to directly measure the coupling of the Higgs to the top quark. In particular the ttH production has not been observed in the Run 1 of LHC but becomes accessible with the increase of energy to sqrt(s) = 13 TeV in the Run 2. The ttH(H->bb) channel uses a Maximum Likelihood fit of predicted distribution to Data in order to extract the signal strength and significance. I was in charge of this complex statistical analysis as well as the definition of the input model and its systematics.
Search for doubly charged scalar bosons decaying to W± W± with ATLAS at LHC
Ellajosyula Venugopal
A search for doubly charged scalar bosons decaying to charged vector bosons is performed using a data sample collected in 2015 and 2016 by the ATLAS detector at the LHC at a centre-of-mass energy of 13 TeV. The search is guided by a model including an extension of the scalar sector through an scalar triplet, leading to a rich phenomenology that includes singly- and doubly-charged bosons, two new pseudo-scalar bosons and a scalar boson associated to the SM Higgs boson. We consider a simplified scenario in which only the doubly charged Higgs bosons are light enough to be produced at the LHC. The doubly-charged bosons H++/-- are produced by pairs and dominantly decay to electroweak gauge bosons H++/-- -> W+/-W+/-. The mass range from 200 to 700 GeV is explored using the experimental signatures with three leptons, missing transverse energy and at least two jets. A multi-variate, mass dependent analysis optimisation is performed. Preliminary results indicate an unique discovery potential for the benchmark model.
Estimation of fake lepton background in the two same-sign lepton ttH final states with the ATLAS experiment at LHC
Hadef Asma
The search for ttH production benefits with the dataset of 2015-2016 @ √s=13 TeV from a ten times increased statistics than in the first run, which will allow to measure directly for the first time the top-Higgs Yukawa coupling and indirectly search for New Physics. In the multilepton ttH, the
generic signature of two leptons (electron or muon) of same- sign electric charge is almost SM
background free. Fake leptons are the main detector background though. Its estimation is performed using data-driven method using pT parametrization that relies on real and fake lepton efficiencies measurements. First public results using 2015+2016 data @ √s=13 TeV were issued last summer and show consistency with the Standard Model expectation. Further studies are ongoing to reduce the contribution of fake leptons and its corresponding uncertainties.
To be continued in the afternoon
Join the meeting by clicking this link: https://vidyoportal.cern.ch/flex.html?roomdirect.html&key=R8hWPzxNsly4
