Presentation on theme: "Little Higgs Dark Matter and Its Implications at the LHC Chuan-Ren Chen (NTNU) XS 2014, 5/6/2014 In collaboration with H-C Tsai, M-C Lee, 1402.6815[hep-ph]"— Presentation transcript:
Little Higgs Dark Matter and Its Implications at the LHC Chuan-Ren Chen (NTNU) XS 2014, 5/6/2014 In collaboration with H-C Tsai, M-C Lee, 1402.6815[hep-ph]
w/ light T-odd leptons CRC (NTNU) 26 M h = 125 GeV are so light! LHC should be able to produce lots of them. Planck2013 + WMAP-9yrs
light T-odd leptons at LHC 8 TeV CRC (NTNU) 27 f (GeV) dilepton + met lepton + met large production cross section 1 ~ 10 pb met only 100%
arbitrary P t (e) (GeV) CRC (NTNU) 28 dilepton + met dilepton + MET search at LHC: slepton pair or chargino pair in SUSY NO Constraint
MT2 (GeV) arbitrary CRC (NTNU) 29 dilepton + met dilepton + MET search at LHC: NO Constraint slepton pair or chargino pair in SUSY kill all signals
CRC (NTNU) 30 one lepton + MET search at LHC: f (GeV) lepton + met search for W’ one high pt lepton + large MT M T (GeV) M T > 1 TeV kill signal NO constraint from current data
light T-odd leptons at LHC 8 TeV CRC (NTNU) 31 arbitrary P t (e) (GeV) f (GeV) dilepton + met lepton + met met only charged lepton is soft! can contribute mono-jet + met signal at LHC soft direct search is very challenging!
w/ light T-odd leptons CRC (NTNU) 32 M h = 125 GeV Direct search:
CRC (NTNU) 34 w/ light T-odd quarks 3 down-type: 3 up-type: degenerate case inconsistent with stable heavy quark search at colliders However, ∵ ( M t_ - M AH ) < M W < M top top partner ONLY has 4-body decay channel, decay life time is too long!
CRC (NTNU) 35 w/ non-degenerate T-odd quarks projective LUX 2014 can explore M AH up to ~190 GeV, future expts can explore whole parameter space.
CRC (NTNU) 36 arbitrary P t (j) (GeV) HUGE production cross section, jet p T is very soft! light T-odd quarks at the LHC dijet + MET search is very challenging!
CRC (NTNU) 37 light T-odd quarks at the LHC contributes to mono-jet BSM search at LHC. soft
CRC (NTNU) 38 95% C.L. exclusion 2.8 pb 0.16 pb 0.05 pb 0.02 pb f < ~1.4 TeV (M AH < ~ 220 GeV) is DISFAVORED. light T-odd quarks at the LHC allow one other jet > 35 GeV
CRC (NTNU) 39 Summary With M h = 125 GeV, co-annihilation is needed for heavier (not ~ M h /2) dark matter in LHT model to explain current universe. In co-annihilation region, T-odd new heavy fermions should be very light, large production cross section at the LHC. The small mass difference between dark matter and T-odd leptons makes collider search very difficult. light T-odd top quark partner decays “too late” -> not allowed by collider searches. mono-jet + MET from light T-odd quarks + 1jet production at the LHC exceed current limit if M AH < 220 GeV. Future DM direct search exps can explore whole parameter space.
CRC (NTNU) 45 “heavy neutrino” can NOT be a dark matter KK neutrino in UED model relic density elastic scattering w/ nuclei ~ 2x10 -3 pb >> 10 -9 pb (current limit) same as SM coupling Servant, Tait, hep-ph/0206071 Servant, Tait, hep-ph/0209262
mono-jet +MET at LHC CRC (NTNU) 46 95% C.L. exclusion 2.8 pb 0.16 pb 0.05 pb 0.02 pb SR3: jet P t > 350 GeV NO constraint from current data