1,750 research outputs found
Two-loop scalar self-energies and pole masses in a general renormalizable theory with massless gauge bosons
I present the two-loop self-energy functions for scalar bosons in a general
renormalizable theory, within the approximation that vector bosons are treated
as massless or equivalently that gauge symmetries are unbroken. This enables
the computation of the two-loop physical pole masses of scalar particles in
that approximation. The calculations are done simultaneously in the
mass-independent \bar{MS}, \bar{DR}, and \bar{DR}' renormalization schemes, and
with arbitrary covariant gauge fixing. As an example, I present the two-loop
SUSYQCD corrections to squark masses, which can increase the known one-loop
results by of order one percent. More generally, it is now straightforward to
implement all two-loop sfermion pole mass computations in supersymmetry using
the results given here, neglecting only the electroweak vector boson masses
compared to the superpartner masses in the two-loop parts.Comment: 16 pages, 4 figures. v2: typo in eq. (5.30) fixe
Decays of Supersymmetric Particles: the program SUSY-HIT (SUspect-SdecaY-Hdecay-InTerface)
We present the program package SUSY-HIT for the computation of supersymmetric
particle decays within the framework of the Minimal Supersymmetric extension of
the Standard Model. The code is based on two existing programs HDECAY and
SDECAY for the calculation of the decay widths and branching ratios of,
respectively, the MSSM Higgs bosons and the SUSY particles, and calls a program
for the calculation of the SUSY particle spectrum such as SuSpect. Including
all important higher order effects, the package allows the consistent
calculation of the MSSM particle spectrum and decays with the presently highest
level of precision.Comment: 8 pages, no figure
Chargino and Neutralino Decays Revisited
We perform a comprehensive analysis of the decays of charginos and
neutralinos in the Minimal Supersymmetric Standard Model where the neutralino
is assumed to be the lightest supersymmetric particle. We focus, in
particular, on the three-body decays of the next-to-lightest neutralino and the
lightest chargino into the lightest neutralino and fermion-antifermion pairs
and include vector boson, Higgs boson and sfermion exchange diagrams, where in
the latter contribution the full mixing in the third generation is included.
The radiative corrections to the heavy fermion and SUSY particle masses will be
also taken into account. We present complete analytical formulae for the Dalitz
densities and the integrated partial decay widths in the massless fermion case,
as well as the expressions of the differential decay widths including the
masses of the final fermions and the polarization of the decaying charginos and
neutralinos. We then discuss these decay modes, in particular in scenarios
where the parameter is large and in models without universal
gaugino masses at the Grand Unification scale where some new decay channels,
such as decays into gluinos and pairs, open up.Comment: 51 pages with 13 figures, latex; uses axodraw.sty and epsfig.st
HDECAY: a Program for Higgs Boson Decays in the Standard Model and its Supersymmetric Extension
We describe the Fortran code HDECAY which calculates the decay widths and the
branching ratios of the Standard Model Higgs boson, and of the neutral and
charged Higgs particles of the Minimal Supersymmetric extension of the Standard
Model. The program is self-contained (with all subroutines included), easy to
run, fast and calculates the decay widths and branching ratios according to the
current theoretical knowledge.Comment: LaTeX, 26 pages, 3 ps figures include
An update of the constraints on the phenomenological MSSM from the new LHC Higgs results
Updated results on the search of Higgs bosons at the LHC with up to 17/fb of
data have just been presented by the ATLAS and CMS collaborations. New
constraints are provided by the LHCb and XENON experiments with the observation
of the rare decay B_s -> mu+mu- and new limits on dark matter direct detection.
In this paper, we update and extend the results on the implications of these
data on the phenomenological Minimal Supersymmetric extension of the Standard
Model (pMSSM) by using high statistics, flat scans of its 19 parameters. The
new LHC data on bb and tau tau decays of the lightest Higgs state and the new
CMS limits from the tau tau searches for the heavier Higgs states set stronger
constraints on the pMSSM parameter space.Comment: 14 pages, 8 figures. This update is based on results presented at HCP
2012 and the December 2012 CERN Council LHC Jamboree. It features larger scan
statistics and additional plot
Implications of LHC Higgs and SUSY searches for MSSM
The implications of the LHC SUSY searches as well as the discovery of a new
bosonic state compatible with the lightest Higgs boson will be discussed in the
context of constrained and general MSSM scenarios. Exploring the MSSM through
the Higgs sector is an alternative and complementary path to direct searches,
and tight constraints on the MSSM parameter space can be obtained.Comment: 7 pages, 5 figures, contribution to the ICHEP 2012 Conference
proceedings, 4-11 July 2012, Melbourne, Australi
Search for a Higgs Boson Decaying into Two Photons with the L3 Detector at LEP
A search is performed for a Higgs boson, decaying into two photons, using the
L3 data collected at centre of mass energies between = 189 and 202
GeV, corresponding to an integrated luminosity of 400 pb. The processes
, , are considered. The observed data are found to be consistent with the
expected background from standard physics processes. Limits on the branching
fraction of the Higgs boson decay into two photons as a function of the Higgs
mass are shown and a lower mass limit on a fermiophobic Higgs is derived.Comment: 3 pages, 2 postscript figures, Presented at the DPF2000 Conference,
August 9-12, 2000, The Ohio State University, Columbus, Ohi
Two-Photon Decay Widths of Higgs Particles
Two--photon decays of Higgs bosons are important channels for the search of
these particles in the intermediate mass range at the colliders LHC and
SSC. Dynamical aspects of the Higgs coupling to two photons can also be studied
by means of the fusion of Higgs particles at high--energy
ee linear colliders. Extending earlier analyses which had been
restricted to the Standard Model, we present in this note the QCD radiative
corrections to the decay widths of scalar and pseudoscalar
Higgs particles in multi--doublet extensions of the Higgs sector, as realized
for instance in supersymmetric theories.Comment: 8pages + 3figures (not included, a hard copy is available from A.D.
upon request), Prep. DESY 92-170 (to appear in Phys. Lett. B
The Search for Higgs particles at high-energy colliders: Past, Present and Future
I briefly review the Higgs sector in the Standard Model and its minimal
Supersymmetric extension, the MSSM. After summarizing the properties of the
Higgs bosons and the present experimental constraints, I will discuss the
prospects for discovering these particle at the upgraded Tevatron, the LHC and
a high-energy linear collider. The possibility of studying the
properties of the Higgs particles will be then summarized.Comment: 28 pages, latex, 15 figures, talk at WHEPP VII, Allahabad, Indi
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