89 research outputs found
Top Quark and Higgs Boson Masses in Supersymmetric Models
We study the implications for bounds on the top quark pole mass m_t in models
with low scale supersymmetry following the discovery of the Standard Model-like
Higgs boson. In the minimal supersymmetric standard model, we find that m_t >=
164 GeV, if the light CP even Higgs boson mass m_h = 125 +-2 GeV. We also
explore the top quark and Higgs boson masses in two classes of supersymmetric
SO(10) models with t-b-tau Yukawa coupling unification at M_GUT. In particular,
assuming SO(10) compatible non-universal gaugino masses, setting m_h = 125 GeV
and requiring 5% or better Yukawa unification, we obtain the result 172 GeV <=
m_t <= 175 GeV. Conversely, demanding 5% or better t-b-tau Yukawa unification
and setting m_t=173.2 GeV, the Higgs boson mass is predicted to lie in the
range 122 GeV <= m_h <= 126 GeV.Comment: 16 pages, 7 figure
Coannihilation Scenarios and Particle Spectroscopy in SU(4)_c x SU(2)_L x SU(2)_R
We identify a variety of coannihilation scenarios in a supersymmetric SU(4)_c
x SU(2)_L x SU(2)_R model with discrete left-right symmetry. Non-universal
gaugino masses, compatible with the gauge symmetry, play an essential role in
realizing gluino and bino-wino coannihilation regions that are consistent with
the WMAP dark matter constraints. We also explore regions of the parameter
space in which the little hierarchy problem is partially resolved. We present
several phenomenologically interesting benchmark points and the associated
sparticle and Higgs mass spectra.Comment: 16 pages, 5 figures and 1 tabl
Soft Probes of SU(5) Unification
We explore the sparticle and Higgs spectroscopy of an SU(5) inspired
extension of the constrained minimal supersymmetric standard model (CMSSM). The
universal soft parameter m_0 is replaced by m_{\bar 5} and m_{10}, where
m_{\bar 5} and m_{10} denote universal soft scalar masses associated with
fields in the five and ten dimensional representations of SU(5). The special
case m_{\bar 5} << m_{10} yields a rather characteristic sparticle spectroscopy
which can be tested at the LHC. We highlight a few benchmark points in which
the lightest neutralino saturates the WMAP bound on cold dark matter abundance.Comment: 23 pages, 10 figures, 2 table
3.5 keV X-ray line and R-Parity Conserving Supersymmetry
We present some R-parity conserving supersymmetric models which can
accommodate the 3.5 keV X-ray line reported in recent spectral studies of the
Perseus galaxy cluster and the Andromeda galaxy. Within the Minimal
Supersymmetric Standard Model (MSSM) framework, the dark matter (DM) gravitino
(or the axino) with mass of around 7 keV decays into a massless neutralino
(bino) and a photon with lifetime ~10^{28} sec. The massless bino contributes
to the effective number of neutrino species N_eff and future data will test
this prediction. In the context of NMSSM, we first consider scenarios where the
bino is massless and the singlino mass is around 7 keV. We also consider
quasi-degenerate bino-singlino scenarios where the mass scale of DM particles
are O(GeV) or larger. In such a scenario we require the mass gap to generate
the 3.5 keV line. We comment on the possibility of a 7 keV singlino decaying
via R parity violating couplings while all other neutralinos are heavy.Comment: 16 pages, 4 figures, updated to reflect journal versio
CMSSM Spectroscopy in light of PAMELA and ATIC
Dark matter neutralinos in the constrained minimal supersymmetric model
(CMSSM) may account for the recent cosmic ray electron and positron
observations reported by the PAMELA and ATIC experiments either through self
annihilation or via decay. However, to achieve this, both scenarios require new
physics beyond the 'standard' CMSSM, and a unified explanation of the two
experiments suggests a neutralino mass of order 700 GeV - 2 TeV. A relatively
light neutralino with mass around 100 GeV (300 GeV) can accomodate the PAMELA
but not the ATIC observations based on a model of annihilating (decaying)
neutralinos. We study the implications of these scenarios for Higgs and
sparticle spectroscopy in the CMSSM and highlight some benchmark points. An
estimate of neutrino flux expected from the annihilating and decaying
neutralino scenarios is provided.Comment: 14 pages, 8 figures, 2 tables; References added; color coding fixed
in some figure
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