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.Comment: 21 pages, 3 figure

A 750 GeV Diphoton Signal from a Very Light Pseudoscalar in the NMSSM

The excess of events in the diphoton final state near 750 GeV observed by ATLAS and CMS can be explained within the NMSSM near the R-symmetry limit. Both scalars beyond the Standard Model Higgs boson have masses near 750 GeV, mix strongly, and share sizeable production cross sections in association with b-quarks as well as branching fractions into a pair of very light pseudoscalars. Pseudoscalars with a mass of ~ 210 MeV decay into collimated diphotons, whereas pseudoscalars with a mass of ~ 500-550 MeV can decay either into collimated diphotons or into three pi^0 resulting in collimated photon jets. Various such scenarios are discussed; the dominant constraints on the latter scenario originate from bounds on radiative Upsilon decays, but they allow for a signal cross section up to 6.7 fb times the acceptance for collimated multiphotons to pass as a single photon.Comment: Major update, 21 pages, scenarios with M_A ~ 210 MeV and M_A ~ 550 MeV added, references and output files from NMSSMTools added, section and figure on Delta_eta of diphotons added. To appear in JHE

The semi-constrained NMSSM satisfying bounds from the LHC, LUX and Planck

We study the parameter space of the semi-constrained NMSSM, compatible with constraints on the Standard Model like Higgs mass and signal rates, constraints from searches for squarks and gluinos, a dark matter relic density compatible with bounds from WMAP/Planck, and direct detection cross sections compatible with constraints from LUX. The remaining parameter space allows for a fine-tuning as low as about 100, an additional lighter Higgs boson in the 60-120 GeV mass range detectable in the diphoton mode or in decays into a pair of lighter CP-odd Higgs bosons, and dominantly singlino like dark matter with a mass down to 1 GeV, but possibly a very small direct detection cross section.Comment: 19 pages, 13 Figure

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.Comment: Typos corrected, references added, radiative corrections written out explicitely in new appendix

Additional Higgs Bosons near 95 and 650 GeV in the NMSSM

Hints for an additional Higgs boson with a mass of about 95 GeV originate from LEP and searches in the diphoton channel by CMS and ATLAS. A search for resonant production of SM plus BSM Higgs bosons in the diphoton plus bb channel by CMS showed some excess for a 650 GeV resonance decaying into the SM Higgs plus a 95 GeV Higgs boson. We investigate whether these phenomena can be interpreted simultaneously within the NMSSM subject to the latest constraints on couplings of the SM Higgs boson, on extra Higgs bosons from the LHC, and on dark matter direct detection cross sections.Comment: 14 pages, 12 Figure

NMSSM with correct relic density and an additional 95 GeV Higgs boson

We investigate whether it is possible within the NMSSM to describe simultaneously a correct dark matter relic density complying with the latest null results from the LZ experiment, an extra Higgs boson with a mass of ~95 GeV visible in the bb channel at LEP and the diphoton channel at the LHC, and the deviation of the anomalous magnetic moment of the muon from its value within the Standard Model. We find that this is still possible for a variety of dark matter annihilation mechanisms, for singlino-like but also bino-like lightest supersymmetric particles. We show the signal rates of the extra Higgs boson and the dark matter detection rates as function of the dark matter mass and annihilation mechanism. The dark matter direct detection cross section may well fall below the neutrino floor. The masses of the lightest electroweakly interacting supersymmetric particles are typically not far above 100 GeV, but not excluded due to unconventional decays.Comment: 17 Pages, 12 Figures, 4 Tables, Reference added, to appear in EPJ

Constraints from Charge and Colour Breaking Minima in the (M+1)SSM

We study the constraints on the parameter space of the supersymmetric standard model extended by a gauge singlet, which arise from the absence of global minima of the effective potential with slepton or squark vevs. Particular attention is paid to the so-called ``UFB'' directions in field space, which are F-flat in the MSSM. Although these directions are no longer F-flat in the (M+1)SSM, we show that the corresponding MSSM-like constraints on m_0/M_{1/2} apply also to the (M+1)SSM. The net effect of all constraints on the parameter space are more dramatic than in the MSSM. We discuss the phenomenological implications of these constraints.Comment: 18 pages (LaTeX2e), 1 fi

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.Comment: 12 pages, 3 figs, improved (generalized) treatment of CP odd loop contributions; the possibility to get large negative contributions to the lightest Higgs mass is clarified in a third figure; typos correcte

MWM_W, Dark Matter and aμa_\mu in the NMSSM

We study regions in the parameter space of the NMSSM which are able to simultaneously explain the current measured values for the $W$ mass $M_W$ and the muon anomalous magnetic moment $a_\mu$, and provide a dark matter relic density consistent with the observations as well as constraints from detection experiments. The corresponding regions feature light charginos, sleptons and staus in the 100-800~GeV range, at least some of them with masses below 150~GeV such that the electroweakly-interacting SUSY particles generate sufficiently large contributions to $M_W$. The LSP is always singlino-like with a mass below 140~GeV, and could possibly remain invisible even at future detection experiments. Decays of electroweak sparticles proceed through cascades via staus and/or sleptons which makes their detection challenging. We propose benchmark points for future searches of such sparticles. The lightest CP-even scalar may have a mass in the 95-98~GeV range with, however, modest signal rates in view of the mild excesses reported in this range at LEP and by CMS at the LHC.Comment: 8 pages, 6 figures, references added, figures improved, SLHA files of bench mark points added as ancillary file

NMSSM Explanation for Excesses in the Search for Neutralinos and Charginos and a 95 GeV Higgs Boson

The observed excesses in the search for neutralinos and charginos by ATLAS and CMS can be fitted simultaneously in the minimal supersymmetric standard model (MSSM) assuming a light higgsino mass, of magnitude less than about 250 GeV, and a compressed higgsino dominated neutralino and chargino spectrum, with $5-10\%$ mass splittings. However, light higgsinos as dark matter would have far too large direct detection cross sections. We consider the next-to-MSSM (NMSSM) with an additional singlino-like lightest supersymmetric particle (LSP) a few GeV below the next-to-lightest supersymmetric particle (NLSP). Sparticles prefer to decay first into the NLSP and remnants from the final decay into the LSP are too soft to contribute to the observed signals. Co-annihilation in the higgsino-sector can generate a relic density in the WMAP/Planck window. The singlino-like LSP has automatically a direct detection cross section below present and future sensitivities: a direct detection signal in the near future would exclude this scenario. The singlet-like Higgs scalar of the NMSSM can have a mass around 95 GeV and signal cross sections in the $b\bar{b}$ channel at LEP and in the $\gamma\gamma$ channel at the LHC compatible with the respective observations.Comment: 17 pages, 9 Figures, 4 Table