517 research outputs found
Double-Spin Asymmetry of J/psi Production in Polarized pp Collisions at HERA-
We calculated the color-octet contribution to the double spin asymmetry of
hadroproduction with nonzero transverse momenta at fixed target
energies GeV. It is shown that the color-octet contribution
is dominant in the asymmetries. The expected asymmetries and statistical errors
in a future option of HERA with longitudinally polarized protons at HERA- should allow one to distinguish between different parametrizations for the
polarized gluon distribution in the proton.Comment: 14 pages with 6 figures (epsfig), LaTeX; Some figures are changed and
misprint is correcte
Hadroproduction and Polarization of Charmonium
In the limit of heavy quark mass, the production cross section and
polarization of quarkonia can be calculated in perturbative QCD. We study the
-averaged production of charmonium states in collisions at
fixed target energies. The data on the relative production rates of \jp and
is found to disagree with leading twist QCD. The polarization of the
\jp indicates that the discrepancy is not due to poorly known parton
distributions nor to the size of higher order effects (-factors). Rather,
the disagreement suggests important higher twist corrections, as has been
surmised earlier from the nuclear target -dependence of the production cross
section.Comment: 19 page
Quarkonium Suppression
I discuss quarkonium suppression in equilibriated strongly interacting
matter. After a brief review of basic features of quarkonium production I
discuss the application of recent lattice data on the heavy quark potential to
the problem of quarkonium dissociation as well as the problem of direct lattice
determination of quarkonium properties in finite temperature lattice QCD.Comment: Invited plenary talk presented on 4th International Conference on
Physics and Astrophysics of Quark Gluon Plasma (ICPAQGP-2001), November
26-30, 2001, Jaipur; 12 pp, LaTeX, uses pramana.st
Psi prime to J/psi Ratio Measurements in PHENIX at RHIC
The ratio of the over the production cross section in the
dielectron channel has been measured in 200 GeV collisions
with the PHENIX detector at RHIC. The analysis is based on fitting of the
dielectron invariant mass spectra in the area around the and
signals in order to extract a ratio over of 0.019statsys and a fractional feed-down contribution to
from of .Comment: 4 pages, 7 figures submitted to: Indian Journal of Physics (2010) -
Proceedings of the 20th International Conference on Ultra-Relativistic
Nucleus-Nucleus Collisions (QM2008
Color-Octet Production at Low
We study contributions from color-octet quarkonium formation mechanisms to
hadroproduction at low . We include transitions of
color-octet states into ``direct'' and into
which decay radiatively into a . Together with earlier work, this
calculation constitutes a complete analysis of -integrated
production at leading twist. We find that the leading-twist contribution is not
sufficient to reproduce the observed production rates and polarization of the
and . Hence there must exist other important quarkonium
production mechanisms at low .Comment: REVTEX, 18 pages, 4 figures include
ratio in Nucleus-Nucleus Collisions : a Measure for the Chiral Symmetry Restoration Temperature ?
We argue that a decrease of the chiral scalar meson mass is responsible for
re-creation of from in ultrarelativistic nucleus-nucleus
collisions. This causes the charmonium yields to freeze out at temperatures
close to the chiral symmetry restoration temperature . As a result
may serve as a thermometer for itself. Results in a detailed
reaction model support the conjecture. They show good agreement with recent
data of NA38 and NA50 for and production in S on U and Pb on
Pb collisions.Comment: 4 pages revtex including 3 postscript figure
B decays
We review the prospects for B decay studies at the LHC. Contributing authors: J. Baines, S.P. Baranov, P. Bartalini, M. Beneke, E. Bouhova, G. Buchalla, I. Caprini, F. Charles, J. Charles, Y. Coadou, P. Colangelo, P. Colrain, J. Damet, F. De Fazio, A. Dighe, H. Dijkstra, P. Eerola, N. Ellis, B. Epp, S. Gadomski, P. Galumian, I. Gavrilenko, S. George, V.M. Ghete, V. Gibson, L. Guy, Y. Hasegawa, P. Iengo, A. Jacholkowska, R. Jones, A. Khodjamirian, E. Kneringer, P. Koppenburg, H. Korsmo, N. Labanca, L. Lellouch, M. Lehto, Y. Lemoigne, J. Libby, J. Matias, S. Mele, M. Misiak, A.M. Nairz, T. Nakada, A. Nikitenko, N. Nikitin, A. Nisati, F. Palla, E. Polycarpo, J. Rademacker, F. Rizatdinova, S. Robins, D. Rousseau, W. Ruckstuhl, M.A. Sanchis, O. Schneider, M. Shapiro, C. Shepherd-Themistocleous, P. Sherwood, L. Smirnova, M. Smizanska, A. Starodumov, N. Stepanov, Z. Xie, N. Zaitse
Roflumilast in moderate-to-severe chronic obstructive pulmonary disease treated with longacting bronchodilators: two randomised clinical trials
Background Patients with chronic obstructive pulmonary disease (COPD) have few options for treatment. The efficacy and safety of the phosphodiesterase-4 inhibitor roflumilast have been investigated in studies of patients with moderate-to-severe COPD, but not in those concomitantly treated with longacting inhaled bronchodilators. The effect of roflumilast on lung function in patients with COPD that is moderate to severe who are already being treated with salmeterol or tiotropium was investigated. Methods In two double-blind, multicentre studies done in an outpatient setting, after a 4-week run-in, patients older than 40 years with moderate-to-severe COPD were randomly assigned to oral roflumilast 500 mu g or placebo once a day for 24 weeks, in addition to salmeterol (M2-127 study) or tiotropium (M2-128 study). The primary endpoint was change in prebronchodilator forced expiratory volume in 1s (FEV(1)). Analysis was by intention to treat. The studies are registered with ClinicalTrials.gov, number NCT00313209 for M2-127, and NCT00424268 for M2-128. Findings In the salmeterol plus roflumilast trial, 466 patients were assigned to and treated with roflumilast and 467 with placebo; in the tiotropium plus roflumilast trial, 371 patients were assigned to and treated with roflumilast and 372 with placebo. Compared with placebo, roflumilast consistently improved mean prebronchodilator FEV(1) by 49 mL (p<0.0001) in patients treated with salmeterol, and 80 mL (p<0.0001) in those treated with tiotropium. Similar improvement in postbronchodilator FEV(1) was noted in both groups. Furthermore, roflumilast had beneficial effects on other lung function measurements and on selected patient-reported outcomes in both groups. Nausea, diarrhoea, weight loss, and, to a lesser extent, headache were more frequent in patients in the roflumilast groups. These adverse events were associated with increased patient withdrawal. Interpretation Roflumilast improves lung function in patients with COPD treated with salmeterol or tiotropium, and could become an important treatment for these patients
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