Search for supersymmetry with sneutrino as the LSP using same sign di-leptons at √s = 7 TeV

Abstract

This study presents the first search for supersymmetry with sneutrino as the LSP in final states containing same sign di-leptons at √s = 7 TeV. The inclusive search is performed with events characterized by large MET as well as hadronic activities. The data sample corresponding to an integrated luminosity of 35 pb−1 was collected by CMS in 2010. No excess above the standard model background expectation is observed. Limits are set on the parameters of the SUSY framework with slepton NLSP and sneutrinos as the LSP. For similar squark and gluino masses, as well as degenerate neutralino and chargino masses, gluino masses below 685 GeV for a range of chargino masses are excluded at 95% confidence level.

Motivation

Motivated by recent developments in the field [1-3]. We study a topology with sneutrinos as the LSP with slepton NLSP. The current constraints [1] as well the cross sections for dominant initiated sparticles are given below. The cross sections are computed using Next to Leading Order calculation Prospino.

sneutrino1.png sneutrino2.png

We consider squarks and gluinos to be of similar masses, with chargino and neutralino mass degeneracy. The slepton and sneutrino masses are set to be ~ 130 GeV and ~ 100 GeV respectively. A typical decay chain can be given as:

sneutrino3.png

We expect same and opposite sign leptons in equal proportions from both ends of the decay chains.

Results and analysis selection

The same sign dilpton selection is the same as presented in the SUS-10-004 paper (CERN-PH-EP-2011-033) using Pt leptons > 20 and 10 GeV. The following plot shows the CMS exclusion as a function of the chargino and gluino masses using MET > 80 GeV, Njet > 1 with HT > 60 GeV. The dashed lines represent the theoretical uncertainties due to scale and PDF choices. The study in both axes probes both strong and weak scales simultaneously.

sneutrino.png

The gluino 4-body decays in the above mentioned chain are currently not available in pythia 6.4.22

References

  • 1. Nima Arkani-Hamed, Lawrence J. Hall, Hitoshi Murayama, David Tucker-Smith, Neal Weiner, “Small neutrino masses from supersymmetry breaking”, Phys. Rev. D64:115011,2001.
  • 2. Zachary Thomas, David Tucker-Smith, (Williams Coll.) , Neal Weiner, “Mixed Sneutrinos, Dark Matter and the CERN LHC.” Phys.Rev.D77:115015,2008
  • 3. A. Katz and B. Tweedie, “Signals of a Sneutrino (N)LSP at the LHC,” Phys. Rev. D 81, 035012 (2010)

Additional information for CMS members

-- SanjayPadhi - 21-Mar-2011

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Topic revision: r1 - 2011-04-11 - SanjayPadhi
 
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