TY - JOUR
T1 - Mixed sneutrinos, dark matter, and the CERN LHC
AU - Thomas, Zachary
AU - Tucker-Smith, David
AU - Weiner, Neal
PY - 2008/6/18
Y1 - 2008/6/18
N2 - We study the phenomenology of supersymmetric models in which gauge-singlet scalars mix with the minimal supersymmetric standard model (MSSM) sneutrinos through weak-scale A terms. After reviewing the constraints on mixed-sneutrino dark matter from measurements of ΩCDM and from direct-detection experiments, we explore mixed-sneutrino signatures relevant to the LHC. For a mixed-sneutrino lightest supersymmetric particle (LSP) and a right-handed slepton next-to-lightest supersymmetric particle (NLSP), decays of the lightest neturalino can produce opposite-sign, same-flavor (OSSF) dileptons with an invariant-mass distribution shifted away from the kinematic end point. This signature is possible for parameters that lead to a cosmologically viable mixed-sneutrino LSP. We also consider signatures that require larger mixing angles than preferred for mixed-sneutrino dark matter, but which are possible regardless of whether a mixed-sneutrino is the LSP. In some parameter regions, the charginos and neutralinos produced in cascades all decay dominantly to the lighter sneutrinos, leading to a kinematic edge in the jet-lepton invariant-mass distribution from the decay chain q∼→χ-q→ν∼*lq, without an OSSF dilepton signature. We explore the possibility of using mass-estimation methods to distinguish this mixed-sneutrino jet-lepton signature from an MSSM one. Finally, we consider signatures associated with Higgs-lepton or Z-lepton production in cascades involving the heavier sneutrinos.
AB - We study the phenomenology of supersymmetric models in which gauge-singlet scalars mix with the minimal supersymmetric standard model (MSSM) sneutrinos through weak-scale A terms. After reviewing the constraints on mixed-sneutrino dark matter from measurements of ΩCDM and from direct-detection experiments, we explore mixed-sneutrino signatures relevant to the LHC. For a mixed-sneutrino lightest supersymmetric particle (LSP) and a right-handed slepton next-to-lightest supersymmetric particle (NLSP), decays of the lightest neturalino can produce opposite-sign, same-flavor (OSSF) dileptons with an invariant-mass distribution shifted away from the kinematic end point. This signature is possible for parameters that lead to a cosmologically viable mixed-sneutrino LSP. We also consider signatures that require larger mixing angles than preferred for mixed-sneutrino dark matter, but which are possible regardless of whether a mixed-sneutrino is the LSP. In some parameter regions, the charginos and neutralinos produced in cascades all decay dominantly to the lighter sneutrinos, leading to a kinematic edge in the jet-lepton invariant-mass distribution from the decay chain q∼→χ-q→ν∼*lq, without an OSSF dilepton signature. We explore the possibility of using mass-estimation methods to distinguish this mixed-sneutrino jet-lepton signature from an MSSM one. Finally, we consider signatures associated with Higgs-lepton or Z-lepton production in cascades involving the heavier sneutrinos.
UR - http://www.scopus.com/inward/record.url?scp=45749143112&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=45749143112&partnerID=8YFLogxK
U2 - 10.1103/PhysRevD.77.115015
DO - 10.1103/PhysRevD.77.115015
M3 - Article
AN - SCOPUS:45749143112
SN - 1550-7998
VL - 77
JO - Physical Review D - Particles, Fields, Gravitation and Cosmology
JF - Physical Review D - Particles, Fields, Gravitation and Cosmology
IS - 11
M1 - 115015
ER -