401 research outputs found
Wh plus missing-E_T signature from gaugino pair production at the LHC
In SUSY models with heavy squarks and gaugino mass unification, the gaugino
pair production reaction pp-> \tw_1^\pm\tz_2 dominates gluino pair production
for m_{\tg}\agt 1 TeV at LHC with \sqrt{s}=14 TeV (LHC14). For this mass range,
the two-body decays \tw_1\to W\tz_1 and \tz_2\to h\tz_1 are expected to
dominate the chargino and neutralino branching fractions. By searching for \ell
b\bar{b}+MET events from \tw_1^\pm\tz_2 production, we show that LHC14 with 100
fb^{-1} of integrated luminosity becomes sensitive to chargino masses in the
range m_{\tw_1}\sim 450-550 GeV corresponding to m_{\tg}\sim 1.5-2 TeV in
models with gaugino mass unification. For 10^3 fb^{-1}, LHC14 is sensitive to
the Wh channel for m_{\tw_1}\sim 300-800 GeV, corresponding to m_{\tg}\sim
1-2.8 TeV, which is comparable to the reach for gluino pair production followed
by cascade decays. The Wh+MET search channel opens up a new complementary
avenue for SUSY searches at LHC, and serves to point to SUSY as the origin of
any new physics discovered via multijet and multilepton + MET channels.Comment: 5 pages with 4 .eps figure
Testing the gaugino AMSB model at the Tevatron via slepton pair production
Gaugino AMSB models-- wherein scalar and trilinear soft SUSY breaking terms
are suppressed at the GUT scale while gaugino masses adopt the AMSB form--
yield a characteristic SUSY particle mass spectrum with light sleptons along
with a nearly degenerate wino-like lightest neutralino and quasi-stable
chargino. The left- sleptons and sneutrinos can be pair produced at
sufficiently high rates to yield observable signals at the Fermilab Tevatron.
We calculate the rate for isolated single and dilepton plus missing energy
signals, along with the presence of one or two highly ionizing chargino tracks.
We find that Tevatron experiments should be able to probe gravitino masses into
the ~55 TeV range for inoAMSB models, which corresponds to a reach in gluino
mass of over 1100 GeV.Comment: 14 pages including 6 .eps figure
Vacuum Stability and Radiative Symmetry Breaking of the Scale-Invariant Singlet Extension of Type II Seesaw Model
The questions of the origin of electroweak symmetry breaking and neutrino
mass are two major puzzles in particle physics. Neutrino mass generation
requires new physics beyond the Standard Model and also suggests
reconsideration of physics of symmetry breaking. The aim of this paper is to
study radiative symmetry breaking in the singlet scalar extension of type II
seesaw neutrino mass model. We derive bounded-from-below conditions for the
scalar potential of the model in full generality for the first time. The
Gildener-Weinberg approach is utilised in minimising the multiscalar potential.
Upon imposing the bounded-from-below and perturbativity conditions, as well as
experimental constraints from colliders, we find the parameter space of scalar
quartic couplings that can radiatively realise electroweak symmetry breaking at
one-loop level. To satisfy all the constraints, the masses of the heavy
triplet-like Higgs bosons must be nearly degenerate. The evolution of the Higgs
doublet quartic coupling can be prevented from being negative up
to the Planck scale.Comment: 20 pages, 4 figure
Same-Sign Diboson Signature from Supersymmetry Models with Light Higgsinos at the LHC
In supersymmetric models with light Higgsinos (which are motivated by electroweak naturalness arguments), the direct production of Higgsino pairs may be difficult to search for at the LHC due to the low visible energy release from their decays. However, the wino pair production reaction [?] -\u3e ([?]) + ([?]) also occurs at substantial rates and leads to final states including equally oppositesign and same-sign diboson production. We propose a novel search channel for LHC14 based on the same-sign diboson plus missing ET final state which contains only modest jet activity. Assuming gaugino mass unification, and an integrated luminosity [?] 100 fb-1, this search channel provides a reach for supersymmetry well beyond that from usual gluino pair production
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