Threshold Resummation for W-Boson Production at RHIC

We study the resummation of large logarithmic perturbative corrections to the partonic cross sections relevant for the process pp -> W^+- X at the BNL Relativistic Heavy Ion Collider (RHIC). At RHIC, polarized protons are available, and spin asymmetries for this process will be used for precise measurements of the up and down quark and anti-quark distributions in the proton. The corrections arise near the threshold for the partonic reaction and are associated with soft-gluon emission. We perform the resummation to next-to-leading logarithmic accuracy, for the rapidity-differential cross section. We find that resummation leads to relatively moderate effects on the cross sections and spin asymmetries.Comment: 25 pages, 15 figures as eps files. One reference added and typo correcte

Measurement of the nuclear modification factor of electrons from heavy-flavour decays at mid-rapidity in Pb-Pb collisions at sNN\sqrt{s_{\rm NN}} = 2.76 TeV with ALICE

We present results on inclusive electrons for 1.5 $< p_{\rm T} <$ 6 GeV/$c$ in {Pb-Pb} collisions at $\sqrt{s_{\rm NN}}$ = 2.76 TeV measured with ALICE at the LHC and compare these to a cocktail of background electron sources. The excess of electrons beyond the cocktail at high momenta ({$p_{\rm T} >$ 3.5 GeV/$c$}) is attributed to electrons from heavy-flavour decays. The corresponding nuclear modification factor indicates heavy-flavour suppression by a factor of 1.5-4.Comment: 4 pages; 4 figures; QM 2011 proceeding

Longitudinal spin transfer of Lambda and anti-Lambda in polarized pp collisions at \sqrt s=200 GeV at STAR

We report our measurement on longitudinal spin transfer, D_LL, from high energy polarized protons to $\Lambda$ and $\bar{\Lambda}$ hyperons in proton-proton collisions at $\sqrt{s} = 200 GeV$ with the STAR detector at RHIC. The current measurements cover $\Lambda$, $\bar\Lambda$ pseudorapidity $|\eta| < 1.2$ and transverse momenta $p_T$ up to $4GeV/c$ using the data taken in 2005. The longitudinal spin transfer is found to be D_LL= -0.03\pm 0.13 (stat) \pm 0.04(syst)$for inclusive$\Lambda$and$D_{LL} = -0.12 \pm 0.08(stat) \pm 0.03(syst)$for inclusive$\bar{\Lambda}$hyperons with$ = 0.5$and$ = 3.7 GeV/c$. The prospects with 2009 data and the future measurements are also given.Comment: 6 pages, 3 figures, presentation at the SPIN2010 International Symposium, Juelich (Germany), Sep. 27-Oct. 2, 201

A high-dose pulse steroid regimen for controlling active chronic graft-versus-host disease

AbstractCorticosteroids remain essential for controlling active chronic graft-versus-host disease (cGVHD). However, the optimum dose and administration schedule is unknown. We have reviewed our results in 61 patients with severe refractory cGVHD who were treated with a high-dose pulse steroid regimen (PS) consisting of methylprednisolone at 10 mg/kg per day for 4 consecutive days, with subsequent tapering doses. After 4 days, all patients received a course of additional immunosuppressive therapy. The median age of the 56 patients who were evaluable for response was 32 years (range, 0.2-57 years). Patients had failed a median of 2 (range, 1-5) treatments prior to the PS. The median follow-up for 45 surviving patients after PS was 1.5 years. The probability of survival at 1 year and 2 years after PS was 88% (95% confidence interval [CI], 76%-95%) and 81% (95% CI, 65%-91%), respectively. Twenty-seven patients (48%) showed a major response to PS with substantial improvement of cGVHD manifestations, including softening of the skin, increased range of motion, and improved performance status; 15 patients (27%) showed a minor response, defined as improvement in some but not all symptoms of cGVHD. Of the 42 responders, 21 (50%) had progression of their cGVHD afterwards. The median time to progression was 1.9 years. The probability of progression at 1 and 2 years after PS was 36% (95% CI, 23%-53%) and 54% (95% CI, 38%-71%), respectively. The probability of progression at 1 year was 25% (95% CI, 12%-47%) and 55% (95% CI, 32%-81%) for patients who had major and minor response, respectively (hazard ratio, 2.13). Ten of the 42 responders (24%) were able to discontinue all systemic immunosuppressive treatments. The probability of discontinuation at 1 and 2 years after PS was 9% (95% CI, 3%-25%) and 27% (95% CI, 15%-48%), respectively. The treatment was well tolerated with no serious adverse events. Our results suggest that PS is a well-tolerated regimen for achieving rapid clinical response in the majority of patients with cGVHD who failed on multiple previous therapies. Further studies are warranted to maintain the efficacy of this regimen by combining with new active agents in cGVHD.Biol Blood Marrow Transplant 2001;7(9):495-502

Polarized semi-inclusive electroweak structure functions at next-to-leading-order

We present a next-to-leading order (NLO) computation of the full set of polarized and unpolarized electroweak semi-inclusive DIS (SIDIS) structure functions, whose knowledge is crucial for a precise extraction of polarized parton distributions. We focus on the phenomenology of the polarized structure functions for the kinematical conditions that could be reached in an Electron-Ion-Collider. We show that the NLO corrections are sizeable, particularly in the small-$x$ range. We test the sensitivity of these structure functions on certain quark distributions and compare it to the situation of inclusive DIS and electromagnetic SIDIS.Comment: 17 pages, 5 figure

Next-to-leading Order Evolution of Transversity Distributions and Soffer's Inequality

We present a calculation of the two-loop splitting functions for the evolution of the twist-2 `transversity' parton densities of transversely polarized nucleons. We study the implications of our results for Soffer's inequality for the case of valence quark densities.Comment: 23 Pages, LaTeX, 2 figures as eps files, final, slightly modified version, to appear in Phys. Rev.

Double logarithms, ln2(1/x)ln^2(1/x), and the NLO DGLAP evolution for the non-singlet component of the nucleon spin structure function, g1g_1

Theoretical predictions show that at low values of Bjorken $x$ the spin structure function, $g_1$ is influenced by large logarithmic corrections, $ln^2(1/x)$, which may be predominant in this region. These corrections are also partially contained in the NLO part of the standard DGLAP evolution. Here we calculate the non-singlet component of the nucleon structure function, $g_1^{NS}=g_1^p-g_1^n$, and its first moment, using a unified evolution equation. This equation incorporates the terms describing the NLO DGLAP evolution and the terms contributing to the $ln^2(1/x)$ resummation. In order to avoid double counting in the overlapping regions of the phase-space, a unique way of including the NLO terms into the unified evolution equation is proposed. The scheme-independent results obtained from this unified evolution are compared to the NLO fit to experimental data, GRSV'2000. Analysis of the first moments of $g_1^{NS}$ shows that the unified evolution including the $ln^2(1/x)$ resummation goes beyond the NLO DGLAP analysis. Corrections generated by double logarithms at low $x$ influence the $Q^2$-dependence of the first moments strongly.Comment: 13 pages, latex, 2 figures; Appendix adde