5,124 research outputs found
Pair Production of Charged Higgs Bosons from Bottom-Quark Fusion
For very large values of , charged Higgs boson pair production at
the Large Hadron Collider (LHC) from the scattering of two bottom quarks can
proceed dominantly. We investigated the cross sections of charged Higgs boson
pair production via the subprocess at the LHC including
the next-to-leading order (NLO) QCD corrections in the minimal supersymmetric
standard model (MSSM). We find that the NLO QCD corrections can significantly
reduce the dependence of the cross sections on the renormalization and
factorization scales.Comment: small changes are mad
Flavor changing effects on single charged Higgs boson production associated with a bottom-charm pair at CERN Large Hadron Collider
We study flavor changing effects on the \ppbchT process at the Large Hadron
Collider(LHC), which are inspired by the left-handed up-type squark mixings in
the Minimal Supersymmetric Standard Model(MSSM). We find that the SUSY QCD
radiative corrections to coupling can significantly enhance the cross
sections at the tree-level by a factor about with our choice of
parameters. We conclude that the squark mixing mechanism in the MSSM makes the
\ppbchT process a new channel for discovering a charged Higgs boson and
investigating flavor changing effects.Comment: One Latex file, 27 pages, 8 figures,to be appeared in PR
Full one-loop supersymmetric corrections to charged Higgs boson pair production in collisions
The complete one-loop electroweak corrections to charged Higgs boson pair
production in collision mode at linear colliders in the minimal
supersymmetric standard model (MSSM), are calculated in this paper. We discuss
the dependence of the corrections to the subprocess on the related parameters, such as the colliding energy, charged
Higgs boson mass and some supersymmetric parameters ,
and gaugino mass parameter . We find that the corrections
generally reduce the Born cross sections and the relative one-loop corrections
to both the subprocess typically in the range of -10% to -30%. We also present
the numerical results at the SPS1a' point from the SPA project. We conclude
that the full one-loop electroweak corrections to subprocess and the parent process
are significant and therefore should be considered in precise analysis of
charged Higgs boson pair productions via collision at future
linear colliders.Comment: accepted by Phys.Rev.
Pair production of neutral Higgs bosons at the CERN Large Hadron Collider
We study the hadroproduction of two neutral Higgs bosons in the minimal
supersymmetric extension of the standard model, which provides a handle on the
trilinear Higgs couplings. We include the contributions from quark-antiquark
annihilation at the tree level and those from gluon-gluon fusion, which
proceeds via quark and squark loops. We list compact results for the tree-level
partonic cross sections and the squark loop amplitudes, and we confirm previous
results for the quark loop amplitudes. We quantitatively analyze the hadronic
cross sections at the CERN Large Hadron Collider assuming a favorable
supergravity-inspired scenario.Comment: 22 pages (Latex), 16 figures (Postscript). Discussion of theoretical
uncertainties and background processes added. Accepted for publication in
Phys. Rev.
The Conformal Anomaly of M5-Branes
We show that the conformal anomaly for N M5-branes grows like . The
method we employ relates Coulomb branch interactions in six dimensions to
interactions in four dimensions using supersymmetry. This leads to a relation
between the six-dimensional conformal anomaly and the conformal anomaly of N=4
Yang-Mills. Along the way, we determine the structure of the four derivative
interactions for the toroidally compactified (2,0) theory, while encountering
interesting novelties in the structure of the six derivative interactions.Comment: 38 pages, LaTeX; references adde
Extreme Technicolor & The Walking Critical Temperature
We map the phase diagram of gauge theories of fundamental interactions in the
flavor-temperature plane using chiral perturbation theory to estimate the
relation between the pion decaying constant and the critical temperature above
which chiral symmetry is restored. We then investigate the impact of our
results on models of dynamical electroweak symmetry breaking and therefore on
the electroweak early universe phase transition.Comment: RevTeX, 18 pages, 3 figure
StopCOVID cohort : An observational study of 3,480 patients admitted to the Sechenov University hospital network in Moscow city for suspected COVID-19 infection
Š 2020 Oxford University Press. This is a pre-copyedited, author-produced PDF of an article accepted for publication in Clinical Infectious Diseases following peer review. The version of record is available online at: https://doi.org/10.1093/cid/ciaa1535.BACKGROUND: The epidemiology, clinical course, and outcomes of COVID-19 patients in the Russian population are unknown. Information on the differences between laboratory-confirmed and clinically-diagnosed COVID-19 in real-life settings is lacking. METHODS: We extracted data from the medical records of adult patients who were consecutively admitted for suspected COVID-19 infection in Moscow, between April 8 and May 28, 2020. RESULTS: Of the 4261 patients hospitalised for suspected COVID-19, outcomes were available for 3480 patients (median age 56 years (interquartile range 45-66). The commonest comorbidities were hypertension, obesity, chronic cardiac disease and diabetes. Half of the patients (n=1728) had a positive RT-PCR while 1748 were negative on RT-PCR but had clinical symptoms and characteristic CT signs suggestive of COVID-19 infection.No significant differences in frequency of symptoms, laboratory test results and risk factors for in-hospital mortality were found between those exclusively clinically diagnosed or with positive SARS-CoV-2 RT-PCR.In a multivariable logistic regression model the following were associated with in-hospital mortality; older age (per 1 year increase) odds ratio [OR] 1.05 (95% confidence interval (CI) 1.03 - 1.06); male sex (OR 1.71, 1.24 - 2.37); chronic kidney disease (OR 2.99, 1.89 - 4.64); diabetes (OR 2.1, 1.46 - 2.99); chronic cardiac disease (OR 1.78, 1.24 - 2.57) and dementia (OR 2.73, 1.34 - 5.47). CONCLUSIONS: Age, male sex, and chronic comorbidities were risk factors for in-hospital mortality. The combination of clinical features were sufficient to diagnoseCOVID-19 infection indicating that laboratory testing is not critical in real-life clinical practice.Peer reviewe
Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV
The performance of muon reconstruction, identification, and triggering in CMS
has been studied using 40 inverse picobarns of data collected in pp collisions
at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection
criteria covering a wide range of physics analysis needs have been examined.
For all considered selections, the efficiency to reconstruct and identify a
muon with a transverse momentum pT larger than a few GeV is above 95% over the
whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4,
while the probability to misidentify a hadron as a muon is well below 1%. The
efficiency to trigger on single muons with pT above a few GeV is higher than
90% over the full eta range, and typically substantially better. The overall
momentum scale is measured to a precision of 0.2% with muons from Z decays. The
transverse momentum resolution varies from 1% to 6% depending on pseudorapidity
for muons with pT below 100 GeV and, using cosmic rays, it is shown to be
better than 10% in the central region up to pT = 1 TeV. Observed distributions
of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO
Multiplicity dependence of jet-like two-particle correlations in p-Pb collisions at = 5.02 TeV
Two-particle angular correlations between unidentified charged trigger and
associated particles are measured by the ALICE detector in p-Pb collisions at a
nucleon-nucleon centre-of-mass energy of 5.02 TeV. The transverse-momentum
range 0.7 5.0 GeV/ is examined,
to include correlations induced by jets originating from low
momen\-tum-transfer scatterings (minijets). The correlations expressed as
associated yield per trigger particle are obtained in the pseudorapidity range
. The near-side long-range pseudorapidity correlations observed in
high-multiplicity p-Pb collisions are subtracted from both near-side
short-range and away-side correlations in order to remove the non-jet-like
components. The yields in the jet-like peaks are found to be invariant with
event multiplicity with the exception of events with low multiplicity. This
invariance is consistent with the particles being produced via the incoherent
fragmentation of multiple parton--parton scatterings, while the yield related
to the previously observed ridge structures is not jet-related. The number of
uncorrelated sources of particle production is found to increase linearly with
multiplicity, suggesting no saturation of the number of multi-parton
interactions even in the highest multiplicity p-Pb collisions. Further, the
number scales in the intermediate multiplicity region with the number of binary
nucleon-nucleon collisions estimated with a Glauber Monte-Carlo simulation.Comment: 23 pages, 6 captioned figures, 1 table, authors from page 17,
published version, figures at
http://aliceinfo.cern.ch/ArtSubmission/node/161
Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV
The performance of muon reconstruction, identification, and triggering in CMS
has been studied using 40 inverse picobarns of data collected in pp collisions
at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection
criteria covering a wide range of physics analysis needs have been examined.
For all considered selections, the efficiency to reconstruct and identify a
muon with a transverse momentum pT larger than a few GeV is above 95% over the
whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4,
while the probability to misidentify a hadron as a muon is well below 1%. The
efficiency to trigger on single muons with pT above a few GeV is higher than
90% over the full eta range, and typically substantially better. The overall
momentum scale is measured to a precision of 0.2% with muons from Z decays. The
transverse momentum resolution varies from 1% to 6% depending on pseudorapidity
for muons with pT below 100 GeV and, using cosmic rays, it is shown to be
better than 10% in the central region up to pT = 1 TeV. Observed distributions
of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO
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