888 research outputs found
The impact of the ATLAS zero-lepton, jets and missing momentum search on a CMSSM fit
Recent ATLAS data significantly extend the exclusion limits for
supersymmetric particles. We examine the impact of such data on global fits of
the constrained minimal supersymmetric standard model (CMSSM) to indirect and
cosmological data. We calculate the likelihood map of the ATLAS search, taking
into account systematic errors on the signal and on the background. We validate
our calculation against the ATLAS determinaton of 95% confidence level
exclusion contours. A previous CMSSM global fit is then re-weighted by the
likelihood map, which takes a bite at the high probability density region of
the global fit, pushing scalar and gaugino masses up.Comment: 16 pages, 7 figures. v2 has bigger figures and fixed typos. v3 has
clarified explanation of our handling of signal systematic
The lightest Higgs boson production at photon colliders in the 2HDM-III
The branching ratios of the lightest CP-even Higgs boson , in the
framework of the General Two Higgs Doublet Model are calculated. Different
scenarios are presented taking into account constraints obtained in previous
works on the flavor changing neutral currents factors. Plausible scenarios with
flavour changing processes at tree level like and are
analyzed for relevant region of parameters. The loop-induced Higgs couplings to
photon pairs can be tested with a photon collider. The number of events of
as a resonance in photon colliders are calculated taking into account its
corresponding background signal in TESLA, CLIC and NLC.Comment: 1. Universidad Nacional de Colombia, Bogota, Colombia. (2)
Universidad de Valencia, Valencia, Spain. 21 pages, 5 figures, RevTe
New Results for Light Gravitinos at Hadron Colliders - Tevatron Limits and LHC Perspectives
We derive Feynman rules for the interactions of a single gravitino with
(s)quarks and gluons/gluinos from an effective supergravity Lagrangian in
non-derivative form and use them to calculate the hadroproduction cross
sections and decay widths of single gravitinos. We confirm the results obtained
previously with a derivative Lagrangian as well as those obtained with the
non-derivative Lagrangian in the high-energy limit and elaborate on the
connection between gauge independence and the presence of quartic vertices. We
perform extensive numerical studies of branching ratios, total cross sections,
and transverse-momentum spectra at the Tevatron and the LHC. From the latest
CDF monojet cross section limit, we derive a new and robust exclusion contour
in the gravitino-squark/gluino mass plane, implying that gravitinos with masses
below to eV are excluded for
squark/gluino-masses below 200 and 500 GeV, respectively. These limits are
complementary to the one obtained by the CDF collaboration,
eV, under the assumption of infinitely heavy squarks and gluinos. For the LHC,
we conclude that SUSY scenarios with light gravitinos will lead to a striking
monojet signal very quickly after its startup.Comment: 30 pages, 12 figures. Tevatron limit improved and unitarity limit
included. Version to be published in Phys. Rev.
Hadron Collider Sensitivity to Fat Flavourful s for
We further investigate the case where new physics in the form of a massive
particle explains apparent measurements of lepton flavour
non-universality in decays. Hadron collider
sensitivities for direct production of such s have been previously
studied in the narrow width limit for a final state. Here, we
extend the analysis to sizeable decay widths and improve the sensitivity
estimate for the narrow width case. We estimate the sensitivities of the high
luminosity 14 TeV Large Hadron Collider (HL-LHC), a high energy 27 TeV LHC
(HE-LHC), as well as a potential 100 TeV future circular collider (FCC). The
HL-LHC has sensitivity to narrow resonances consistent with the
anomalies. In one of our simplified models the FCC could probe 23 TeV
particles with widths of up to 0.35 of their mass at 95\% confidence
level (CL). In another model, the HL-LHC and HE-LHC cover sizeable portions of
parameter space, but the whole of perturbative parameter space can be covered
by the FCC.Comment: 24 pages, 11 figures; v2 Reference
Interpreting a 1 fb^-1 ATLAS Search in the Minimal Anomaly Mediated Supersymmetry Breaking Model
Recent LHC data significantly extend the exclusion limits for supersymmetric
particles, particularly in the jets plus missing transverse momentum channels.
The most recent such data have so far been interpreted by the experiment in
only two different supersymmetry breaking models: the constrained minimal
supersymmetric standard model (CMSSM) and a simplified model with only squarks
and gluinos and massless neutralinos. We compare kinematical distributions of
supersymmetric signal events predicted by the CMSSM and anomaly mediated
supersymmetry breaking (mAMSB) before calculating exclusion limits in mAMSB. We
obtain a lower limit of 900 GeV on squark and gluino masses at the 95%
confidence level for the equal mass limit, tan(beta)=10 and mu>0.Comment: 18 pages, 11 figure
Requirements on collider data to match the precision of WMAP on supersymmetric dark matter
If future colliders discover supersymmetric particles and probe their
properties, one could predict the dark matter density of the Universe and would
constrain cosmology with the help of precision data provided by WMAP and
PLANCK.
We investigate how well the relic density can be predicted in minimal
supergravity (mSUGRA), with and without the assumption of mSUGRA when analysing
data. We determine the parameters to which the relic density is most sensitive,
and quantify the collider accuracy needed. Theoretical errors in the prediction
are investigated in some detail.Comment: 42 pages, 16 figures. v2 incorporates referee's comments: minor
corrections/clarifications with additional figures to show regions of m12-m0
plane considere
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Erratum: An anomaly-free atlas: charting the space of flavour-dependent gauged U(1) extensions of the Standard Model (Journal of High Energy Physics, (2019), 2019, 2, (82), 10.1007/JHEP02(2019)082)
We correct a statement in our original paper and add anomaly-free charge assignments for SMν
R
with 7 ≤ Q
max ≤ 10.</jats:p
Study of the Growth of Entropy Modes in MSSM Flat Directions Decay: Constraints on the Parameter Space
We study how the resonant decay of moduli fields arising in the Minimal
Supersymmetric Standard Model (MSSM) could affect large scale curvature
perturbations in the early universe. It has been known for some time that the
presence of entropy perturbations in a multi-component system can act as seeds
for the curvature perturbations on all scales. These entropy perturbations
could be amplified exponentially if one of the moduli decays via stochastic
resonance, affecting the curvature power spectrum in the process. By imposing
the COBE normalization on this power spectrum, one could put constraints on the
masses and couplings of the underlying particle physics model without having to
rely on collider experiments. We discuss in detail the case of the MSSM but
this method could be applied to other theories beyond the Standard Model.Comment: 6 pages, 1 figure, revtex4, comments added in section II, 1 reference
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