909 research outputs found

### Impact of CMS Multi-jets and Missing Energy Search on CMSSM Fits

Recent CMS data significantly extend the direct search exclusion for
supersymmetry. We examine the impact of such data on global fits of the
constrained minimal supersymmetric standard model (CMSSM) to indirect and
cosmological data. By simulating supersymmetric signal events at the LHC, we
construct a likelihood map for the recent CMS data, validating it against the
exclusion region calculated by the experiment itself. A previous CMSSM global
fit is then re-weighted by our likelihood map. The CMS results nibble away at
the high fit probability density region, transforming probability distributions
for the scalar and gluino masses. The CMS search has a non-trivial effect on
tan beta due to correlations between the parameters implied by the fits to
indirect data.Comment: 15 pages, 8 figures. v2 has an appendix added with further checks of
A0-tan beta independence, expected sensitivity curves added to Fig 2a and
typos fixed. v3 has extended discussion of re-weighting procedure and
egregious points in the appendix. v4 minor changes due to very strict (but
good) refere

### Theoretical Uncertainties in Sparticle Mass Predictions

We contrast the sparticle spectra obtained from three modern publicly
available codes along model lines in minimal supersymmetric standard model
(MSSM) parameter space. From this we gain an idea of the uncertainties involved
with sparticle spectra calculations. The differences in predicted sparticle
masses are typically at the several percent-level. In the focus-point scenario,
there are differences of 30% in the weak gaugino masses. These uncertainties
need to be reduced in order to obtain accurate information about fundamental
models of supersymmetry breaking.Comment: revTex4 style. Softsusy homepage is at
http://allanach.home.cern.ch/allanach/softsusy.html Written for Snowmass
2001. Replaced version has updated reference. 3 pages, 3 figure

### Large Hadron Collider constraints on a light baryon number violating sbottom coupling to a top and a light quark

We investigate a model of R-parity violating (RPV) supersymmetry in which the
right-handed sbottom is the lightest supersymmetric particle, and a baryon
number violating coupling involving a top is the only non-negligible RPV
coupling. This model evades proton decay and flavour constraints. We consider
in turn each of the couplings lambda"_{313} and lambda"_{323} as the only
non-negligible RPV coupling, and we recast two recent Large Hadron Collider
(LHC) measurements and searches (CMS top transverse momentum p_T(t) spectrum
and ATLAS multiple jet resonance search) in the form of constraints on the
mass-coupling parameter planes. We delineate a large region in the parameter
space of the mass of the sbottom (m_{b_R}) and the lambda"_{313} coupling that
is ruled out by the measurements, as well as a smaller region in the parameter
space of m_{b_R} and lambda"_{323}. A certain region of the
m_{b_R}-lambda"_{313} parameter space was previously found to successfully
explain the anomalously large ttbar forward backward asymmetry measured by
Tevatron experiments. The entire region is excluded at the 95% CL by CMS
measurements of the top p_T spectrum. We also present p_T(ttbar) distributions
of the forward-backward asymmetry for this model.Comment: 9 pages, 9 figures. v2 has minor corrections, in part due to extra
diagrams at order alpha_s^2 lamba''^

### Comparison of SUSY mass spectrum calculations

We provide a comparison of the results of four SUSY mass spectrum
calculations in mSUGRA: Isajet, SuSpect, SoftSusy, and SPheno. In particular,
we focus on the high tan(beta) and focus point regions, where the differences
in the results are known to be large.Comment: Contribution to SUSY02, 17-23 Jun 2002, DESY Hamburg, 7 page

### Quasi-Fixed Points and Charge and Colour Breaking in Low Scale Models

We show that the current LEP2 lower bound upon the minimal supersymmetric
standard model (MSSM) lightest Higgs mass rules out quasi-fixed scenarios for
string scales between 10^6 and 10^{11} GeV unless the heaviest stop mass is
more than 2 TeV. We consider the implications of the low string scale for
charge and colour breaking (CCB) bounds in the MSSM, and demonstrate that CCB
bounds from F and D-flat directions are significantly weakened. For scales less
than 10^{10} GeV these bounds become merely that degenerate scalar mass squared
values are positive at the string scale.Comment: 17 pages, 4 figures. Replacement has added discussion on errors due
to alpha_s(MZ) errors, as well as deviations from the quasi-fixed point. Text
has been clarifie

### The Case for Future Hadron Colliders From $B \to K^{(*)} \mu^+ \mu^-$ Decays

Recent measurements in $B \to K^{(*)} \mu^+ \mu^-$ decays are somewhat
discrepant with Standard Model predictions. They may be harbingers of new
physics at an energy scale potentially accessible to direct discovery. We
estimate the sensitivity of future hadron colliders to the possible new
particles that may be responsible for the anomalies: leptoquarks or
$Z^\prime$s. We consider luminosity upgrades for a 14 TeV LHC, a 33 TeV LHC,
and a 100 TeV $pp$ collider such as the FCC-hh. Coverage of $Z^\prime$ models
is excellent: for narrow particles, with perturbative couplings that may
explain the $b$-decay results for $Z^\prime$ masses up to 20 TeV, a 33 TeV 1
ab$^{-1}$ LHC is expected to cover most of the parameter space up to 8 TeV in
mass, whereas the 100 TeV FCC-hh with 10 ab$^{-1}$ will cover all of it. A
smaller portion of the leptoquark parameter space is covered by future
colliders: for example, in a $\mu^+\mu^-jj$ di-leptoquark search, a 100 TeV 10
ab$^{-1}$ collider has a projected sensitivity up to leptoquark masses of 12
TeV (extendable to 21 TeV with a strong coupling for single leptoquark
production), whereas leptoquark masses up to 41 TeV may in principle explain
the anomalies.Comment: 24 pages, 10 figures. v2: Improved discussion and references added,
version submitted to JHE

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