104 research outputs found
Rise of Kp Total Cross Section and Universality
The increase of the measured hadronic total cross sections at the highest
energies is empirically described by squared log of center-of-mass energy sqrt
s as sigma(tot)= B (log s)2, consistent with the energy dependence of the
Froissart unitarity bound. The coefficient B is argued to have a universal
value, but this is not proved directly from QCD. In the previous tests of this
universality, the p(pbar)p, pi p, and K p forward scatterings were analyzed
independently and found to be consistent with B(pp) = B(pip) = B(Kp), although
the determined value of B(Kp) had large uncertainty. In the present work, we
have further analyzed forward Kp scattering to obtain a more exact value of
B(Kp). Making use of continuous moment sum rules(CMSR) we have fully exploited
the information of low-energy scattering data to predict the high-energy
behavior of the amplitude hrough duality. The estimation of B(Kp) is improved
remarkably, and our result strongly supports the universality of B.Comment: 12 pages, 3 figure
Searching for Stoponium along with the Higgs boson
Stoponium, a bound state of top squark and its antiparticle in a
supersymmetric model, may be found in the ongoing Higgs searches at the LHC.
Its WW and ZZ detection ratios relative to the Standard Model Higgs boson can
be more than unity from WW* threshold to the two Higgs threshold. The gamma
gamma channel is equally promising. Some regions of the stoponium mass below
150 GeV are already being probed by the ATLAS and CMS experiments.Comment: 10 pages 5 figure
Total Width of 125 GeV Higgs Boson
By using the LHC and Tevatron measurements of the cross sections to various
decay channels relative to the standard model Higgs boson, the total width of
the putative 125 GeV Higgs boson is determined as 6.1 +7.7-2.9 MeV. We describe
a way to estimate the branching fraction for Higgs decay to dark matter. We
also discuss a No-Go theorem for the gammagamma signal of the Higgs boson at
the LHC.Comment: 11 pages, 2 figure
Dilaton at the LHC
The dilaton, a pseudo-Nambu-Goldstone boson appearing in spontaneous scale
symmetry breaking at a TeV scale f, may be found in Higgs boson searches. The
dilaton couples to standard model fermions and weak bosons with the same
structure as the Higgs boson except for the overall strength. Additionally, the
dilaton couples to a Higgs boson pair. The couplings of the dilaton to a gluon
pair and a photon pair, appearing at loop level, are largely enhanced compared
to the corresponding Higgs couplings. We present regions of the mass and VEV of
the dilaton allowed by WW, ZZ, and gammagamma limits from the LHC at 7 TeV with
1.0-2.3 fb-1 integrated luminosity. A scale of f less than 1 TeV is nearly
excluded. We discuss how the dilaton chi can be distinguished from the Higgs
boson h by observation of the decays chi -> gammagamma and chi -> hh ->
(WW)(WW).Comment: 9 pages 4 figure
High energy neutrinos from neutralino annihilations in the Sun
Neutralino annihilations in the Sun to weak boson and top quark pairs lead to
high-energy neutrinos that can be detected by the IceCube and KM3 experiments
in the search for neutralino dark matter. We calculate the neutrino signals
from real and virtual WW, ZZ, Zh, and production and decays,
accounting for the spin-dependences of the matrix elements, which can have
important influences on the neutrino energy spectra. We take into account
neutrino propagation including neutrino oscillations, matter-resonance,
absorption, and nu_tau regeneration effects in the Sun and evaluate the
neutrino flux at the Earth. We concentrate on the compelling Focus Point (FP)
region of the supergravity model that reproduces the observed dark matter relic
density. For the FP region, the lightest neutralino has a large bino-higgsino
mixture that leads to a high neutrino flux and the spin-dependent neutralino
capture rate in the Sun is enhanced by 10^3 over the spin-independent rate. For
the standard estimate of neutralino captures, the muon signal rates in IceCube
are identifiable over the atmospheric neutrino background for neutralino masses
above M_Z up to 400 GeV.Comment: 45 pages, 18 figures and 5 tables, PRD versio
Effects of genuine dimension-six Higgs operators
We systematically discuss the consequences of genuine dimension-six Higgs
operators. These operators are not subject to stringent constraints from
electroweak precision data. However, they can modify the couplings of the Higgs
boson to electroweak gauge bosons and, in particular, the Higgs
self-interactions. We study the sensitivity to which those couplings can be
probed at future \ee linear colliders in the sub-TeV and in the multi-TeV
range. We find that for GeV with a luminosity of 1 ab the
anomalous and couplings may be probed to about the 0.01 level, and
the anomalous coupling to about the 0.1 level.Comment: 21 pages, 17 figures; typos corrected and references adde
Supersymmetry discovery potential of the LHC at 10 and 14 TeV without and with missing
We examine the supersymmetry (SUSY) reach of the CERN LHC operating at
and 14 TeV within the framework of the minimal supergravity
model. We improve upon previous reach projections by incorporating updated
background calculations including a variety of Standard Model (SM)
processes. We show that SUSY discovery is possible even before the detectors
are understood well enough to utilize either or electrons in
the signal. We evaluate the early SUSY reach of the LHC at TeV by
examining multi-muon plus jets and also dijet events with {\it no}
missing cuts and show that the greatest reach in terms of
occurs in the dijet channel. The reach in multi-muons is slightly smaller in
, but extends to higher values of . We find that an observable
multi-muon signal will first appear in the opposite-sign dimuon channel, but as
the integrated luminosity increases the relatively background-free but
rate-limited same-sign dimuon, and ultimately the trimuon channel yield the
highest reach. We show characteristic distributions in these channels that
serve to distinguish the signal from the SM background, and also help to
corroborate its SUSY origin. We then evaluate the LHC reach in various
no-lepton and multi-lepton plus jets channels {\it including} missing
cuts for and 14 TeV, and plot the reach for integrated
luminosities ranging up to 3000 fb at the SLHC. For TeV,
the LHC reach extends to and 2.9 TeV for
and integrated luminosities of 10, 100, 1000 and
3000 fb, respectively. For TeV, the LHC reach for the same
integrated luminosities is to m_{gluino}=2.4,\3.1, 3.7 and 4.0 TeV.Comment: 34 pages, 25 figures. Revised projections for the SUSY reach for
ab^-1 integrated luminosities, with minor corrections of references and text.
2 figures added. To appear in JHE
TeV physics and the Planck scale
Supersymmetry is one of the best motivated possibilities for new physics at
the TeV scale. However, both concrete string constructions and phenomenological
considerations suggest the possibility that the physics at the TeV scale could
be more complicated than the Minimal Supersymmetric Standard Model (MSSM),
e.g., due to extended gauge symmetries, new vector-like supermultiplets with
non-standard SU(2)xU(1) assignments, and extended Higgs sectors. We briefly
comment on some of these possibilities, and discuss in more detail the class of
extensions of the MSSM involving an additional standard model singlet field.
The latter provides a solution to the problem, and allows significant
modifications of the MSSM in the Higgs and neutralino sectors, with important
consequences for collider physics, cold dark matter, and electroweak
baryogenesis.Comment: 17 pages, 5 figures. To appear in New Journal of Physic
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