3,355 research outputs found
Searches for the Higgs Boson with the ATLAS detector at the LHC
Searching for the Higgs boson lies at the heart of the physics program of the Large Hadron Collider (LHC). The prospects for Higgs searches with the ATLAS detector at the LHC are reviewed. The most prominent Higgs final states predicted by the Standard Model and the MSSM are considered. This involves reviewing detector performance and physics analysis strategies. The latter includes defining data-driven approaches to background extraction
Prospects for the Search for a Standard Model Higgs Boson in ATLAS using Vector Boson Fusion
The potential for the discovery of a Standard Model Higgs boson in the mass
range m_H < 2 m_Z in the vector boson fusion mode has been studied for the
ATLAS experiment at the LHC. The characteristic signatures of additional jets
in the forward regions of the detector and of low jet activity in the central
region allow for an efficient background rejection. Analyses for the H -> WW
and H -> tau tau decay modes have been performed using a realistic simulation
of the expected detector performance. The results obtained demonstrate the
large discovery potential in the H -> WW decay channel and the sensitivity to
Higgs boson decays into tau-pairs in the low-mass region around 120 GeV.Comment: 20 pages, 13 ps figures, uses EPJ style fil
HLA-DR and HLA-DQ alleles in patients from the south of Brazil: markers for leprosy susceptibility and resistance
<p>Abstract</p> <p>Background</p> <p>Many epidemiological studies have shown that the genetic factors of the host play a role in the variability of clinical response to infection caused by <it>M. leprae</it>. With the purpose of identifying genes of susceptibility, the present study investigated the possible role of HLA-DRB1 and DQA1/DQB1 alleles in susceptibility to leprosy, and whether they account for the heterogeneity in immune responses observed following infection in a Southern Brazilian population.</p> <p>Methods</p> <p>One hundred and sixty-nine leprosy patients and 217 healthy controls were analyzed by polymerase chain reaction amplification and reverse hybridization with sequence-specific oligonucleotide probes and sequence-specific primers(One Lambda<sup>®</sup>, CA, USA).</p> <p>Results</p> <p>There was a positive association of HLA-DRB1*16 (*1601 and *1602) with leprosy <it>per se </it>(7.3% <it>vs</it>. 3.2%, <it>P </it>= 0.01, OR = 2.52, CI = 1.26–5.01), in accord with previous serological studies, which showed DR2 as a marker of leprosy. Although, HLA-DQA1*05 frequency (29.8% <it>vs</it>. 20.9%, <it>P </it>= 0.0424, OR = 1.61, CI = 1.09–2.39) was higher in patients, and HLA-DQA1*02 (3.0% <it>vs</it>. 7.5%, <it>P </it>= 0.0392, OR = 0.39, CI = 0.16 – 0.95) and HLA-DQA1*04 (4.0% <it>vs</it>. 9.1%, <it>P </it>= 0.0314, OR = 0.42, CI = 0.19 – 0.93) frequencies lower, <it>P</it>-values were not significant after the Bonferroni's correction. Furthermore, HLA-DRB1*1601 (9.0% <it>vs</it>. 1.8%; <it>P </it>= 0.0016; OR = 5.81; CI = 2.05–16.46) was associated with susceptibility to borderline leprosy compared to control group, and while HLA-DRB1*08 (11.2% <it>vs</it>. 1.2%; <it>P </it>= 0.0037; OR = 12.00; CI = 1.51 – 95.12) was associated with susceptibility to lepromatous leprosy, when compared to tuberculoid leprosy, DRB1*04 was associated to protection.</p> <p>Conclusion</p> <p>These data confirm the positive association of HLA-DR2 (DRB1*16) with leprosy <it>per se</it>, and the protector effect of DRB1*04 against lepromatous leprosy in Brazilian patients.</p
Three-month vs. one-year detraining effects after multicomponent exercise program in hypertensive older women
Background: Chronic diseases are the leading causes of death and disability in older
women. Physical exercise training programs promote beneficial effects for health and quality of life.
However, exercise interruption periods may be detrimental for the hemodynamic and lipidic profiles
of hypertensive older women with dyslipidemia. Methods: Nineteen hypertensive older women
with dyslipidemia (exercise group: 67.5 ± 5.4 years, 1.53 ± 3.42 m, 71.84 ± 7.45 kg) performed
a supervised multicomponent exercise training program (METP) during nine months, followed
by a one-year detraining period (DT), while fourteen hypertensive older women (control group:
66.4 ± 5.2 years, 1.56 ± 3.10 m, 69.38 ± 5.24 kg) with dyslipidemia kept their continued daily routine
without exercise. For both groups, hemodynamic and lipidic profiles and functional capacities (FCs)
were assessed four times: before and after the METP and after 3 and 12 months of DT (no exercise
was carried out). Results: The METP improved hemodynamic and lipidic profiles (p < 0.05), while
three months of DT decreased all (p < 0.05) parameters, with the exception of diastolic blood pressure
(DBP). One year of DT significantly (p < 0.01) decreased systolic blood pressure (7.85%), DBP (2.29%),
resting heart rate (7.95%), blood glucose (19.14%), total cholesterol (10.27%), triglycerides (6.92%)
and FC—agility (4.24%), lower- (−12.75%) and upper-body strength (−12.17%), cardiorespiratory
capacity (−4.81%) and lower- (−16.16%) and upper-body flexibility (−11.11%). Conclusion: Nine
months of the exercise program significantly improved the hemodynamic and lipid profiles as well
as the functional capacities of hypertensive older women with dyslipidemia. Although a detraining
period is detrimental to these benefits, it seems that the first three months are more prominent in
these alterations.info:eu-repo/semantics/publishedVersio
The Higgs Working Group: Summary Report (2001)
Report of the Higgs working group for the Workshop `Physics at TeV
Colliders', Les Houches, France, 21 May - 1 June 2001. It contains 7 separate
sections: A. Theoretical Developments B. Higgs Searches at the Tevatron C.
Experimental Observation of an invisible Higgs Boson at LHC D. Search for the
Standard Model Higgs Boson using Vector Boson Fusion at the LHC E. Study of the
MSSM channel at the LHC F. Searching for Higgs Bosons in
Production G. Studies of Charged Higgs Boson Signals for the
Tevatron and the LHCComment: 120 pages, latex, many figures, proceedings of the Workshop `Physics
at TeV Colliders', Les Houches, France, 21 May - 1 June 2001, full Author
list included in paper. Typos corrected, author list and acknowledgements
completed. Convernors: D. Cavalli, A. Djouadi, K. Jakobs, A. Nikitenko, M.
Spira, C.E.M. Wagner, W.-M. Ya
Measurement of the ttbar Production Cross Section in ppbar Collisions at sqrt(s) = 1.96 TeV
We present a measurement of the top quark pair production cross section in
ppbar collisions at sqrt(s)=1.96 TeV using 318 pb^{-1} of data collected with
the Collider Detector at Fermilab. We select ttbar decays into the final states
e nu + jets and mu nu + jets, in which at least one b quark from the t-quark
decays is identified using a secondary vertex-finding algorithm. Assuming a top
quark mass of 178 GeV/c^2, we measure a cross section of 8.7 +-0.9 (stat)
+1.1-0.9 (syst) pb. We also report the first observation of ttbar with
significance greater than 5 sigma in the subsample in which both b quarks are
identified, corresponding to a cross section of 10.1 +1.6-1.4(stat)+2.0-1.3
(syst) pb.Comment: Accepted for publication in Physics Review Letters, 7 page
Polarizations of J/psi and psi(2S) Mesons Produced in ppbar Collisions at 1.96 TeV
We have measured the polarizations of \jpsi and \psiprime mesons as
functions of their transverse momentum \pt when they are produced promptly in
the rapidity range with \pt \geq 5 \pgev. The analysis is performed
using a data sample with an integrated luminosity of about 800 \ipb collected
by the CDF II detector. For both vector mesons, we find that the polarizations
become increasingly longitudinal as \pt increases from 5 to 30 \pgev. These
results are compared to the predictions of nonrelativistic quantum
chromodynamics and other contemporary models. The effective polarizations of
\jpsi and \psiprime mesons from -hadron decays are also reported.Comment: 8 pages, 7 figures, published in Physical Review Letter
Evidence for the exclusive decay Bc+- to J/psi pi+- and measurement of the mass of the Bc meson
We report first evidence for a fully reconstructed decay mode of the
B_c^{\pm} meson in the channel B_c^{\pm} \to J/psi \pi^{\pm}, with J/psi \to
mu^+mu^-. The analysis is based on an integrated luminosity of 360 pb$^{-1} in
p\bar{p} collisions at 1.96 TeV center of mass energy collected by the Collider
Detector at Fermilab. We observe 14.6 \pm 4.6 signal events with a background
of 7.1 \pm 0.9 events, and a fit to the J/psi pi^{\pm} mass spectrum yields a
B_c^{\pm} mass of 6285.7 \pm 5.3(stat) \pm 1.2(syst) MeV/c^2. The probability
of a peak of this magnitude occurring by random fluctuation in the search
region is estimated as 0.012%.Comment: 7 pages, 3 figures. Version 3, accepted by PR
Observation and Mass Measurement of the Baryon
We report the observation and measurement of the mass of the bottom, strange
baryon through the decay chain , where
, , and .
Evidence for observation is based on a signal whose probability of arising from
the estimated background is 6.6 x 10^{-15}, or 7.7 Gaussian standard
deviations. The mass is measured to be (stat.) (syst.) MeV/.Comment: Minor text changes for the second version. Accepted by Phys. Rev.
Let
Search for Third Generation Vector Leptoquarks in p anti-p Collisions at sqrt(s) = 1.96 TeV
We describe a search for a third generation vector leptoquark (VLQ3) that
decays to a b quark and tau lepton using the CDF II detector and 322 pb^(-1) of
integrated luminosity from the Fermilab Tevatron. Vector leptoquarks have been
proposed in many extensions of the standard model (SM). Observing a number of
events in agreement with SM expectations, assuming Yang-Mills (minimal)
couplings, we obtain the most stringent upper limit on the VLQ3 pair production
cross section of 344 fb (493 fb) and lower limit on the VLQ3 mass of 317
GeV/c^2 (251 GeV/c^2) at 95% C.L.Comment: 7 pages, 2 figures, submitted to PR
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