Higgs bosons in supersymmetricU(1)′models withCPviolation

Abstract

We study the Higgs sector of the U(1) ′ -extended MSSM with CP violation. This is an extension of the MSSM Higgs sector by one singlet field, introduced to generate the µ term dynamically. We are particularly interested in non-standard decays of Higgs particles, especially of the lightest one, in the presence of CP violating phases for µ ef f and the soft parameters. We present analytical expressions for neutral and charged Higgs bosons masses at tree and one-loop levels, including contributions from top and bottom scalar quark sectors. We then study the production and decay channels of the neutral Higgs for a set of benchmark points consistent with low energy data and relic density constraints. Numerical simulations show that a Higgs boson lighter than 2m W can decay in a quite distinctive manner, including invisible modes into two neutralinos (h →χ 0χ0 ) up to ∼ 50% of the time, when kinematically allowed. The branching ratio into h →bb, the dominant decay in the SM, is reduced in some U (1) ′ models and enhanced in others, while the branching ratios for the decays h → τ + τ − , h → W W * and h → ZZ * → 4ℓ are always reduced with respect to their SM expectations. This possibility has important implications for testing the U (1) ′ model both at the LHC and later at the ILC.

Neutralino and chargino production in U(1)′ at the LHC

“…In Scenario A, the two lightest pseudoscalar bosons are very light, but these are both singlets [14] which do not couple directly to quarks and leptons [30], and thus the bound for the MSSM-like pseudoscalars does not apply. A complete resolution of this problem is beyond the scope of this work and is dealt with in [19]. For the purpose of this analysis however, we note that a definite conclusion at this point may be premature, as a comprehensive recent analysis still allows for sizable contributions from BSM [31].…”

“…Both can have implications on Higgs physics. For instance, it is possible that the Higgs can decay in a nonstandard fashion, with invisible width due to decays into neutralinos [18,19], while the charginos could be responsible for the enhancement of the Higgs decays into γγ [20]. The production of neutralinos at hadron colliders is an important part of the program of SUSY searches.…”

The Standard Model and Beyond

“…Many of these possibilities have been reexamined in light of the discovery of the Higgslike particle, including models with additional singlets (Frank et al, 2013;Robens and Stefaniak, 2015) or doublets (Baglio et al, 2014;Craig et al, 2015). It has already been commented in Section 8.5.1 that there is a theoretical upper limit of ∼ 135 GeV on the mass of the lightest Higgs scalar in the MSSM, due to the fact that the analog of λ in the SM is given by gauge couplings.…”

Probing U(1) extensions of the MSSM at the LHC Run I and in dark matter searches

“…The h → γγ signal in a U(1) extended MSSM model was discussed in [30,31] with emphasis on the region that leads to an increase in the two-photon signal. Additional non-standard decays of Higgs particles were found in [32,33]. However, since the mass of the additional singlet Higgs is expected to be very large due to strong limits on the Z boson mass, it does not affect the property of the lightest Higgs which is hence expected to be SM-like.…”