Alternative angular variables for QCD multijet background event suppression in SUSY searches at the LHC

Tai Sakuma, H. Flächer, Dominic Smith

Research output: Contribution to conferenceConference Abstract

Abstract

SUSY searches at CMS and ATLAS at LHC are actively ongoing. SUSY particles in R-parity conserved models are usually searched for in events with large missing transverse momentum (MET). QCD events with large MET are rare events. However, because of the large cross section of QCD events, unless they are significantly reduced, QCD background events overwhelm the SUSY signal in the event sample. In searches in all-hadronic final states in CMS and ATLAS, the azimuthal angle between a jet and MET (or MHT) is widely used to reduce QCD background events with large MET, which is caused by a jet pT mismeasurement or neutrinos from semileptonically decaying hadrons in a jet. Another azimuthal angle, the angle between a jet pT and MHT defined with the other jets in the event, is also used to reduce QCD background events in CMS. We have carefully reviewed geometric and analytic properties of these angles and identified room for improvement. We have subsequently developed alternative angular variables which can perform better in rejecting QCD background events in SUSY searches at LHC. In this talk, we will show the definition and physics motivation of the alternative angular variables and demonstrate their performance in Monte-Carlo event samples simulated in DELPHES.
Original languageEnglish
Publication statusUnpublished - 14 Dec 2017
Event25th INTERNATIONAL CONFERENCE ON SUPERSYMMETRY AND THE UNIFICATION OF FUNDAMENTAL INTERACTIONS - Tata Institute of Fundamental Research, Mumbai, India
Duration: 11 Dec 201715 Dec 2017
https://indico.tifr.res.in/indico/conferenceDisplay.py?ovw=True&confId=5736

Conference

Conference25th INTERNATIONAL CONFERENCE ON SUPERSYMMETRY AND THE UNIFICATION OF FUNDAMENTAL INTERACTIONS
Abbreviated titleSUSY17
CountryIndia
CityMumbai
Period11/12/1715/12/17
Internet address

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    Sakuma, T., Flächer, H., & Smith, D. (2017). Alternative angular variables for QCD multijet background event suppression in SUSY searches at the LHC. Abstract from 25th INTERNATIONAL CONFERENCE ON SUPERSYMMETRY AND THE UNIFICATION OF FUNDAMENTAL INTERACTIONS, Mumbai, India.