Search for Supersymmetry with a Compressed Mass Spectrum in Events with a Soft τ Lepton, a Highly Energetic Jet, and Large Missing Transverse Momentum in Proton-Proton Collisions at s =13 TeV


Sirunyan A., Tumasyan A., Adam W., Ambrogi F., Bergauer T., Brandstetter J., ...More

Physical Review Letters, vol.124, no.4, 2020 (SCI-Expanded, Scopus) identifier identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 124 Issue: 4
  • Publication Date: 2020
  • Doi Number: 10.1103/physrevlett.124.041803
  • Journal Name: Physical Review Letters
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Aerospace Database, Chemical Abstracts Core, Compendex, EMBASE, INSPEC, MEDLINE, zbMATH, DIALNET
  • Yıldız Technical University Affiliated: Yes

Abstract

The first search for supersymmetry in events with an experimental signature of one soft, hadronically decaying τ lepton, one energetic jet from initial-state radiation, and large transverse momentum imbalance is presented. These event signatures are consistent with direct or indirect production of scalar τ leptons (τ) in supersymmetric models that exhibit coannihilation between the τ and the lightest neutralino (χ10), and that could generate the observed relic density of dark matter. The data correspond to an integrated luminosity of 77.2 fb-1 of proton-proton collisions at s=13 TeV collected with the CMS detector at the LHC in 2016 and 2017. The results are interpreted in a supersymmetric scenario with a small mass difference (Δm) between the chargino (χ1±) or next-to-lightest neutralino (χ20), and the χ10. The mass of the τ is assumed to be the average of the χ1± and χ10 masses. The data are consistent with standard model background predictions. Upper limits at 95% confidence level are set on the sum of the χ1±, χ20, and τ production cross sections for Δm(χ1±,χ10)=50 GeV, resulting in a lower limit of 290 GeV on the mass of the χ1±, which is the most stringent to date and surpasses the bounds from the LEP experiments.