90 research outputs found
NMSSM with a singlino LSP: possible challenges for searches for supersymmetry at the LHC
A light singlino in the NMSSM can reduce considerably the missing transverse
energy at the end of sparticle decay cascades; instead, light NMSSM-specific
Higgs bosons can be produced. Such scenarios can be consistent with present
constraints from the LHC with all sparticle masses below ~1 TeV. We discuss
search strategies, which do not rely on missing transverse energy, for such
scenarios at the next run of the LHC near 14 TeV.Comment: 20 pages, 9 Figures. References and experimental constraints added;
slight change of benchmark point, conclusions unchange
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Search for supersymmetry in hadronic final states with missing transverse energy using the variables αT and b-quark multiplicity in pp collisions at [Formula: see text].
An inclusive search for supersymmetric processes that produce final states with jets and missing transverse energy is performed in pp collisions at a centre-of-mass energy of 8 TeV. The data sample corresponds to an integrated luminosity of 11.7 fb-1 collected by the CMS experiment at the LHC. In this search, a dimensionless kinematic variable, αT, is used to discriminate between events with genuine and misreconstructed missing transverse energy. The search is based on an examination of the number of reconstructed jets per event, the scalar sum of transverse energies of these jets, and the number of these jets identified as originating from bottom quarks. No significant excess of events over the standard model expectation is found. Exclusion limits are set in the parameter space of simplified models, with a special emphasis on both compressed-spectrum scenarios and direct or gluino-induced production of third-generation squarks. For the case of gluino-mediated squark production, gluino masses up to 950-1125 GeV are excluded depending on the assumed model. For the direct pair-production of squarks, masses up to 450 GeV are excluded for a single light first- or second-generation squark, increasing to 600 GeV for bottom squarks
Excessive Higgs pair production with little MET from squarks and gluinos in the NMSSM
In the presence of a light singlino-like LSP in the NMSSM, the missing
transverse energy - MET - signature of squark/gluino production can be
considerably reduced. Instead, a pair of Higgs bosons is produced in each
event. We propose benchmark points for such scenarios, which differ in the
squark and gluino masses, and in their decay cascades. Events for these points
are simulated for the run II of the LHC at 13 TeV centre of mass energy. After
cuts on the transverse momenta of at least four jets, and requiring two
tau-leptons from one Higgs decay, we find that the invariant mass of two b-jets
from the other Higgs decay shows clear peaks above the background. Despite the
reduced MET, this search strategy allows to see signals for sufficiently large
integrated luminosities, depending on the squark/gluino masses.Comment: 16 pages, 10 figure
SO(10) Grand Unification in M theory on a G2 manifold
We consider Grand Unified Theories based on which originate from
string/ theory on manifolds or Calabi-Yau spaces with discrete
symmetries. In this framework we are naturally led to a novel solution of the
doublet-triplet splitting problem previously considered by Dvali which involves
an extra vector-like Standard Model family and light, but weakly coupled colour
triplets. These additional states are predicted to be accessible at the LHC and
also induce R-parity violation. Gauge coupling unification occurs with a larger
GUT coupling.Comment: 5 pages, added references, revised argument on equation 18, results
unchanged, a new example is given in equation 24, agrees with published
version in Physical Review
Search for supersymmetry in hadronic final states with missing transverse energy using the variables α T and b-quark multiplicity in pp collisions at sâ=8 TeV
An inclusive search for supersymmetric processes that produce final states with jets and missing transverse energy is performed in pp collisions at a centre-of-mass energy of 8 TeV. The data sample corresponds to an integrated luminosity of 11.7 fbâ1 collected by the CMS experiment at the LHC. In this search, a dimensionless kinematic variable, α T, is used to discriminate between events with genuine and misreconstructed missing transverse energy. The search is based on an examination of the number of reconstructed jets per event, the scalar sum of transverse energies of these jets, and the number of these jets identified as originating from bottom quarks. No significant excess of events over the standard model expectation is found. Exclusion limits are set in the parameter space of simplified models, with a special emphasis on both compressed-spectrum scenarios and direct or gluino-induced production of third-generation squarks. For the case of gluino-mediated squark production, gluino masses up to 950â1125 GeV are excluded depending on the assumed model. For the direct pair-production of squarks, masses up to 450 GeV are excluded for a single light first- or second-generation squark, increasing to 600 GeV for bottom squarks
Neutrino mass from M Theory SO(10)
We study the origin of neutrino mass from arising from Theory
compactified on a -manifold. This is linked to the problem of the breaking
of the extra gauge group, in the subgroup of
, which we show can achieved via a (generalised) Kolda-Martin
mechanism. The resulting neutrino masses arise from a combination of the seesaw
mechanism and induced R-parity breaking contributions. The rather complicated
neutrino mass matrix is analysed for one neutrino family and it is shown how
phenomenologically acceptable neutrino masses can emerge.Comment: 32 pages, 12 figure
Search for supersymmetry in hadronic final states with missing transverse energy using the variables a T and b-quark multiplicity in pp collisions at root s = 8 TeV
An inclusive search for supersymmetric processes that produce final states with jets and missing transverse energy is performed in pp collisions at a centre-of-mass energy of 8 TeV. The data sample corresponds to an integrated luminosity of 11.7 fb-1 collected by the CMS experiment at the LHC. In this search, a dimensionless kinematic variable, ? T, is used to discriminate between events with genuine and misreconstructed missing transverse energy. The search is based on an examination of the number of reconstructed jets per event, the scalar sum of transverse energies of these jets, and the number of these jets identified as originating from bottom quarks. No significant excess of events over the standard model expectation is found. Exclusion limits are set in the parameter space of simplified models, with a special emphasis on both compressed-spectrum scenarios and direct or gluino-induced production of third-generation squarks. For the case of gluino-mediated squark production, gluino masses up to 950-1125 GeV are excluded depending on the assumed model. For the direct pair-production of squarks, masses up to 450 GeV are excluded for a single light first- or second-generation squark, increasing to 600 GeV for bottom squarks
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