349 research outputs found

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

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    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

    Masses and Couplings of the Lightest Higgs Bosons in the (M+1)SSM

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    We study the upper limits on the mass of the lightest and second lightest CP even Higgs bosons in the (M+1)SSM, the MSSM extended by a gauge singlet. The dominant two loop contributions to the effective potential are included, which reduce the Higgs masses by 10 GeV. Since the coupling R of the lightest Higgs scalar to gauge bosons can be small, we study in detail the relations between the masses and couplings of both lightest scalars. We present upper bounds on the mass of a 'strongly' coupled Higgs (R > 1/2) as a function of lower experimental limits on the mass of a 'weakly' coupled Higgs (R < 1/2). With the help of these results, the whole parameter space of the model can be covered by Higgs boson searches.Comment: Changed notation and added explanations; to appear in European Journal of Physics

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

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    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

    Higgs Sector of Non-minimal Supersymmetric Models at Future Hadron Colliders

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    We investigate the potential of current and planned hadron colliders operating at the TeV scale in disentangling the structure of the Higgs sector of non-minimal Supersymmetric extensions of the Standard Model with an extra gauge singlet. We assume universality of the soft Supersymmetry breaking terms at the GUT scale as well as a CP-even Higgs boson with mass around 115 GeV, as suggested by LEP. We find that mixing angles between the doublet and singlet Higgs states are always small. However, concrete prospects exist at both the Tevatron (Run II) and the Large Hadron Collider of detecting at least one neutral Higgs state with a dominant singlet component, in addition to those available from a doublet Higgs sector which is similar to the one of the Minimal Supersymmetric Standard Model.Comment: 4 pages, 2 figures, latex, contribution to the APS/DPF/DPB Summer Study on the `Future of Particle Physics (Snowmass 2001)', Snowmass, Colorado, 30 June - 21 July 200

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

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    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

    Neutralino Cascades in the (M+1)SSM

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    In the (M+1)SSM an additional gauge singlet Weyl spinor appears in the neutralino sector. For a large part of the parameter space this approximative eigenstate is the true LSP. Then most sparticle decays proceed via an additional cascade involving the NLSP -> LSP transition, where the NLSP is the non-singlet next-to-lightest neutralino. We present a comprehensive list of all processes, which contribute to the NLSP -> LSP transition, the partial widths and the total NLSP decay rate. We perform a scan of the parameters of the model compatible with universal soft terms, and find that the NLSP life time can be quite large, leading to macroscopically displaced vertices. Our results imply that the signatures for sparticle production in the (M+1)SSM can be very different from the MSSM, and are important for calculations of the abundance of dark matter in this model.Comment: 25 pages (LaTeX2e), 8 figs., explanations adde

    Topologies of the (M+1)SSM with a Singlino LSP at LEP2

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    We study the possible signals of the (M+1)SSM with a singlino LSP at LEP2. First we identify regions of the parameter space which are ruled out by negative results of sparticle searches in the context of the MSSM. In the remaining kinematically accessible regions we present total event rates for topologies which require further studies, i.e. estimations of the corresponding efficiencies: various 4 charged fermion final states with missing energy, possibly with displaced vertices due to a long lifetime of the NLSP, the second lightest neutralino. Searches for these unconventional signatures are essential in order to cover the entire kinematically accessible parameter space of the (M+1)SSM with a singlino LSP at LEP2.Comment: 21 pages (LaTeX2e), 2 figs., table with all possible final states adde

    Los aprendizajes en geografía propuestos a los alumnos de entre 11 y 16 años: actividades básicas

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    Una investigación referente a las actividades de aprendizaje en geografía propuestas a alumnos de edades comprendidas entre los 11 y los 16 años pone de manifiesto que las actividades predominantes son muy básicas y que se centran en un vocabulario y en situaciones elementales. El enfoque que se utiliza es más analítico que sintético o sistémico. Los docentes lo justifican basándose en una concepción analítica de la construcción del saber en general y del saber geográfico en particular.A research into on activities of learning in geography the pupils of 11 to 16 in French secondary schools shows that dominant activities are very elementary, aimed at basic vocabulary and locations, in an approach more analytic than synthetic or systemic. Teachers justify their choices basing them on an analytic idea of the construction of general knowledge and of geographical knowledge in particular.Una investigación referente a las actividades de aprendizaje en geografía propuestas a alumnos de edades comprendidas entre los 11 y los 16 años pone de manifiesto que las actividades predominantes son muy básicas y que se centran en un vocabulario y en situaciones elementales. El enfoque que se utiliza es más analítico que sintético o sistémico. Los docentes lo justifican basándose en una concepción analítica de la construcción del saber en general y del saber geográfico en particular

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

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    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
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