1,287 research outputs found
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
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
The Higgs sector of the phenomenological MSSM in the light of the Higgs boson discovery
The long awaited discovery of a new light scalar at the LHC opens up a new
era of studies of the Higgs sector in the SM and its extensions. In this paper
we discuss the consequences of the observation of a light Higgs boson with the
mass and rates reported by the ATLAS and CMS collaborations on the parameter
space of the phenomenological MSSM, including also the so far unsuccessful LHC
searches for the heavier Higgs bosons and supersymmetric particle partners in
missing transverse momentum as well as the constraints from B physics and dark
matter. We explore the various regimes of the MSSM Higgs sector depending on
the parameters MA and tan beta and show that only two of them are still allowed
by all present experimental constraints: the decoupling regime where there is
only one light and standard--like Higgs boson and the supersymmetric regime in
which there are light supersymmetric particle partners affecting the decay
properties of the Higgs boson, in particular its di-photon and invisible
decays.Comment: 21 pages, 9 figures v2 - Discussion of the impact of LHC data
extended, scan statistics increased, a few figures added and typos correcte
Physics at \ggam and \egam colliders
I discuss, what really new could give Photon Colliders ( and
) after LHC and \epe Linear Collider operations.Comment: 7pages,LaTEX, To be published in proceedings "PHOTON99". The
forgotten title, author and abstract are added in the tex
QCD Corrections to Production of Higgs Pseudoscalars
Models of electroweak symmetry breaking with more than a single doublet of
Higgs scalars contain a neutral pseudoscalar boson. The production of such a
pseudoscalar in hadron collisions proceeds primarily via gluon fusion through a
top-quark loop (except for those models in which the pseudoscalar coupling to
bottom quarks is strongly enhanced). We compute the QCD corrections to this
process in the heavy-quark limit, using an effective Lagrangian derived from
the axial anomaly.Comment: 9 pages, (BNL number added, 1 typo corrected, PHYZZX format, 4
figures not included, available on request), BNL-4906
The Higgs boson in the MSSM in light of the LHC
We investigate the expectations for the light Higgs signal in the MSSM in
different search channels at the LHC. After taking into account dark matter and
flavor constraints in the MSSM with eleven free parameters, we show that the
light Higgs signal in the channel is expected to be at most at
the level of the SM Higgs, while the from W fusion
and/or the can be enhanced. For the main discovery
mode, we show that a strong suppression of the signal occurs in two different
cases: low or large invisible width. A more modest suppression is
associated with the effect of light supersymmetric particles. Looking for such
modification of the Higgs properties and searching for supersymmetric partners
and pseudoscalar Higgs offer two complementary probes of supersymmetry.Comment: 19 pages, 8 figure
SUSY Higgs at the LHC: Effects of light charginos and neutralinos
In view of the latest LEP data we consider the effects of charginos and
neutralinos on the two-photon and bbbar signatures of the Higgs at the LHC.
Assuming the usual GUT inspired relation between M_1 and M_2 we show that there
are only small regions with moderate tanbeta and large stop mixings that may be
dangerous. Pathological models not excluded by LEP which have degeneracy
between the sneutrino and the chargino are however a real danger because of
large branching fraction of the Higgs into invisibles. We have also studied
models where the gaugino masses are not unified at the GUT scale. We take
M_1=M_2/10 as an example where large reductions in the signal at the LHC can
occur. However we argue that such models with a very light neutralino LSP may
give a too large relic density unless the sleptons are light. We then combine
this cosmological constraint with neutralino production with light sfermions to
further reduce the parameter space that precludes observability of the Higgs at
the LHC. We still find regions of parameter space where the drops in the usual
Higgs signals at the LHC can be drastic. Nonetheless, in such scenarios where
Higgs may escape detection we show that one should be able to produce all
charginos and neutralinos. Although the heavier of these could cascade into the
Higgs, the rates are not too high and the Higgs may not always be recovered
this way.Comment: 37 pages, 17 figures, Latex file, Paper with high resolution figures
can be found at http://wwwlapp.in2p3.fr/web/lapp/preplapp/psth/LAPTH774.ps.g
Refined gluino and squark pole masses beyond leading order
The physical pole and running masses of squarks and gluinos have recently
been related at two-loop order in a mass-independent renormalization scheme. I
propose a general method for improvement of such formulas, and argue that
better accuracy results. The improved version gives an imaginary part of the
pole mass that agrees exactly with the direct calculation of the physical width
at next-to-leading order. I also find the leading three-loop contributions to
the gluino pole mass in the case that squarks are heavier, using effective
field theory and renormalization group methods. The efficacy of these
improvements for the gluino and squarks is illustrated with numerical examples.
Some necessary three-loop results for gauge coupling and fermion mass beta
functions and pole masses in theories with more than one type of fermion
representation, which are not directly accessible from the published
literature, are presented in an Appendix.Comment: 14 pages. v2: typos in equations (A.11), (A.17), and (A.18) fixe
Higgs Physics at Future Colliders: recent theoretical developments
I review the physics of the Higgs sector in the Standard Model and its
minimal supersymmetric extension, the MSSM. I will discuss the prospects for
discovering the Higgs particles at the upgraded Tevatron, at the Large Hadron
Collider, and at a future high--energy linear collider with
centre--of--mass energy in the 350--800 GeV range, as well as the possibilities
for studying their fundamental properties. Some emphasis will be put on the
theoretical developments which occurred in the last two years.Comment: 20 pages, latex, 12 figures. Talk given at PASCOS 2003 (Bombay,
India
- …