arXiv subjects

Cyril Hugonie

Publications and source records attributed to Cyril Hugonie.

24 records · Page 2Linked to original sources

arXiv2006

NMSPEC: A Fortran code for the sparticle and Higgs masses in the NMSSM with GUT scale boundary conditions

NMSPEC is a Fortran code that computes the sparticle and Higgs masses, as well as Higgs decay widths and couplings in the NMSSM, with soft SUSY breaking terms specified at MGUT. Exceptions are the soft singlet mass m_s^2 and the singlet self coupling kappa, that are both determined in terms of the other parameters through the minimization equations of the Higgs potential. We present a first analysis of the NMSSM parameter space with universal SUSY breaking terms at MGUT -- except for m_s and A_kappa -- that passes present experimental constraints on sparticle and Higgs masses. We discuss in some detail a region in parameter space where a SM-like Higgs boson decays dominantly into two CP odd singlet-like Higgs states.

hep-ph↗

arXiv2005

Yukawa Induced Radiative Corrections to the Lightest Higgs Boson Mass in the NMSSM

We compute the leading logarithmic radiative corrections to the lightest Higgs mass in the NMSSM involving the electroweak gauge couplings and in the NMSSM specific Yukawa couplings lambda and kappa (including all mixed combinations), which are induced by chargino, neutralino and Higgs boson loops. The effect of the NMSSM specific Yukawa couplings lambda and kappa is to increase the upper bound on the lightest Higgs mass by up to ~2 GeV, but they can also decrease the lightest Higgs mass by up to ~-20 GeV.

hep-ph↗

arXiv2005

Difficult Scenarios for NMSSM Higgs Discovery at the LHC

We identify scenarios not ruled out by LEP data in which NMSSM Higgs detection at the LHC will be particularly challenging. We first review the `no-lose' theorem for Higgs discovery at the LHC that applies if Higgs bosons do not decay to other Higgs bosons - namely, with L=300 fb^-1, there is always one or more `standard' Higgs detection channel with at least a 5 sigma signal. However, we provide examples of no-Higgs-to-Higgs cases for which all the standard signals are no larger than 7 sigma implying that if the available L is smaller or the simulations performed by ATLAS and CMS turn out to be overly optimistic, all standard Higgs signals could fall below 5 sigma even in the no-Higgs-to-Higgs part of NMSSM parameter space. In the vast bulk of NMSSM parameter space, there will be Higgs-to-Higgs decays. We show that when such decays are present it is possible for all the standard detection channels to have very small significance. In most such cases, the only strongly produced Higgs boson is one with fairly SM-like couplings that decays to two lighter Higgs bosons (either a pair of the lightest CP-even Higgs bosons, or, in the largest part of parameter space, a pair of the lightest CP-odd Higgs bosons). A number of representative bench-mark scenarios of this type are delineated in detail and implications for Higgs discovery at various colliders are discussed.

hep-ph↗

arXiv2005

NMHDECAY: A Fortran Code for the Higgs Masses, Couplings and Decay Widths in the NMSSM

The Fortran code NMHDECAY computes the masses, couplings and decay widths of all Higgs bosons of the NMSSM in terms of its parameters at the electroweak (SUSY breaking) scale: the Yukawa couplings lambda and kappa, the soft trilinear terms A_lambda and A_kappa, and tan(beta) and mu_eff = lambda* . The computation of the spectrum includes leading two loop terms, electroweak corrections and propagator corrections. The computation of the decay widths is carried out as in HDECAY, but (for the moment) without three body decays. Each point in parameter space is checked against negative Higgs bosons searches at LEP, including unconventional channels relevant for the NMSSM. One version of the program uses generalized SLHA conventions for input and output.

hep-ph↗

arXiv2003

Towards a No-Lose Theorem for NMSSM Higgs Discovery at the LHC

We scan the parameter space of the NMSSM for the observability of a Higgs boson at the LHC with $300 {\rm fb}^{-1}$ integrated luminosity per detector, taking the present LEP constraints into account. We focus on the regions of parameter space for which none of the usually considered LHC detection modes are viable due to the fact that the only light non-singlet (and, therefore, potentially visible) Higgs boson, $h$, decays mainly to two CP-odd light Higgs bosons, $h\to a a$. We simulate the $WW\to h \to aa$ detection mode. We find that this signal may be detectable at the LHC as a signal/background $\sim 600/600$ bump in the tail of a rapidly falling mass distribution. If further study gives us confidence that the shape of the background tail is predictable, then we can conclude that NMSSM Higgs detection at the LHC will be possible throughout all of parameter space by combining this signal with the usual detection modes previously simulated by ATLAS and CMS. We also show that this $WW\to h\to aa$ signal will be highly visible at the LC due to its cleaner environment and high luminosity. We present a study of the production modes and decay channels of interest at the LC.

hep-ph↗

arXiv2003

Spontaneous CP Violation in Non-Minimal Supersymmetric Models

We study the possibilities of spontaneous CP violation in the Next-to-Minimal Supersymmetric Standard Model with an extra singlet tadpole term in the scalar potential. We calculate the Higgs boson masses and couplings with radiative corrections including dominant two loop terms. We show that it is possible to satisfy the LEP constraints on the Higgs boson spectrum with non-trivial spontaneous CP violating phases. We also show that these phases could account for the observed value of epsilonK.

hep-ph↗