Collider signatures of a light NMSSM pseudoscalar in neutralino decays in the light of LHC results

Abstract

We investigate signatures induced by a very light pseudoscalar Higgs in neutralino decays in the Next-to-Minimal Supersymmetric Standard Model (NMSSM) and determine their observability at the LHC. We concentrate on scenarios which feature two light scalar Higgs bosons (one of them is SM-like with a mass of 125 GeV and a singlet-like lighter one) with a very light (singlet-like) pseudoscalar Higgs in the mass range 2m τ < m a 0 1 < 2m b . We consider neutralino-chargino pair production and the subsequent decay χ 0 2,3 → χ 0 1 a 0 1 , which leads to topologies involving multi-leptons and missing transverse energy. We determine a set of selection cuts that can effectively isolate the signal from backgrounds of the Standard Model or the Minimal Supersymmetric Standard Model. We also exemplify the procedure with a set of benchmark points, for which we compute the expected number of events and signal strength for LHC with 8 TeV center of mass energy. We show that this signal can already be probed for some points in the NMSSM parameter space.

Two light stops in the NMSSM and the LHC

“…From our knowledge of the MSSM, where the Higgsino mass parameter µ plays a pivotal role in connecting the Higgs, the stop (and the bottom squark (sbottom)) and the electroweak gaugino/higgsino (electroweakino) sectors, it is not difficult to realize how NMSSM parameters could make their interplay even more involved. Studies in the framework of the NMSSM discuss the situations with the Higgs sector [14][15][16][17][18][19][20], the nature and role of the LSP [14,[21][22][23][24][25][26][27][28][29][30][31][32]. Among these, the more recent ones take into account the LHC-results on the Higgs boson and other relevant constraints.…”

“…The fermionic component of the singlet superfieldŜ in equation (2.1) (the 'singlino', S) could mix with the gauginos and the higgsinos of the MSSM. A singlino-dominated neutralino could turn out to be the lightest supersymmetric particle (LSP) and may crucially affect the cascade decays of the heavier SUSY excitations [14,[21][22][23][24][25][26][27][28]. We would further assume that R-parity is conserved and hence the LSP (χ 0 1 ) is stable.…”

Testing the higgsino-singlino sector of the NMSSM with trileptons at the LHC

“…Clearly such decays would reduce the signal rate in the trilepton channel considered hereeven if χ 0 2,3 decay into a light pseudoscalar A 1 with M A 1 < 2M b and A 1 decays dominantly into A 1 → τ + τ − [72,73]. Decays of χ 0 2,3 into heavier Higgs states (decaying into bb), however, start also to be constrained by corresponding searches [74].…”

Investigating light NMSSM pseudoscalar states with boosted ditau tagging

“…In this work, we study Higgs data constraints on the NMSSM and show that phenomenologically viable scenarios feature configurations in which the lightest pseudoscalar A 1 is dominantly produced from the decays of neutralino states [32][33][34]. The LHC constraints on these scenarios are still both rather weak and very model dependent.…”

“…In this work, we focus on the phenomenology of scenarios in which the lightest pseudoscalar state A 1 is mostly singlet-like, so that m 2 33 , and where its mass is heavier than twice the tau lepton mass and lighter than twice the bottom quark mass, m A 1 ∈ [2m τ , 2m b ]. As a consequence, a cancellation between the different terms of eq.…”