Münster 2017 – scientific programme

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T: Fachverband Teilchenphysik

T 76: Flavourphysik 2

T 76.9: Talk

Wednesday, March 29, 2017, 18:50–19:05, JUR 490

Development of a new Soft Muon Tagger in ATLAS — Nello Bruscino, Julien Caudron, Markus Cristinziani, Mazuza Ghneimat, Carlo Alberto Gottardo, Sebastian Heer, Vadim Kostyukhin, •Andrea Sciandra, and Kaven Yau Wong — Physikalisches Institut, Universität Bonn

b-tagging plays a fundamental role at LHC, as it helps in the identification of heavy particles that decay to bottom quarks, as the top quark and the Higgs boson or heavy exotic particles. The Soft Muon Tagger (SMT) allows to identify jets from b-quarks taking advantage of the presence of a muon coming from semileptonic decays of b-hadrons. The SVMT algorithm additionally uses a vertex reconstructed thanks to the high quality of the muon track. I will describe the development of these two new b-taggers in ATLAS, showing that, despite the low efficiency of the jet-muon association (based on the angular distance), the discriminating power of the associated muon and vertex variables is remarkable to reject light jets.
A performance enhancement has been reached at all light jet rejection working points by adding the SMT output to the best performing multivariate b-tagger in ATLAS. A good modelling of input and output variables is shown, comparing simulation with Run 2 data.