B-meson production at forward and backward rapidity in p+p and Cu + Au collisions at √sNN=200 GeV

The fraction of J/psi mesons which come from B-meson decay, F-B -> J/psi is measured for J/psi rapidity 1.2 0 in p + p and Cu+Au collisions at root s(NN) = 200 GeV with the PHENIX detector. The extracted fraction is F-B -> J/psi = 0.025 +/- 0.006 (stat) +/- 0.010(syst) for p + p collisions. For Cu+Au collisions, F-B -> J/psi is 0.094 +/- 0.028(stat) +/- 0.037(syst) in the Au-going direction (-2.2 <y <-1.2) and 0.089 +/- 0.026(stat) +/- 0.040(syst) in the Cu-going direction (1.2 <y <2.2). The nuclear modification factor, R-CuAu,of B mesons in Cu+Au collisions is consistent with binary scaling of measured yields in p + p at both forward and backward rapidity.Peer reviewe

Role of splenectomy for immune thrombocytopenic purpura (ITP) in the era of new second-line therapies and in the setting of a high prevalence of HIV-associated ITP

Background. New agents are being used as second-line treatment for immune thrombocytopenia (ITP) and have brought into question the relevance of splenectomy for steroid-resistant ITP.Methods. We retrospectively analysed 73 patients who underwent splenectomy for ITP at our institution over an 11-year period. The median follow-up period was 25 months; patients with follow-up of &lt;1 month were excluded. The outcomes of splenectomy were compared in HIV-positive v. HIV-negative patients.Results. The rate of complete response was 83%, and response was sustained for at least 1 year or until latest follow-up in 80% of patients. Twelve patients were HIV-positive. Splenectomy was laparoscopic in 43 patients (62%) with an overall 16% complication rate. The 90-day mortality rate was 1.38%. There was no statistically significant difference in response or complication rate in the HIV-positive patients. There was a statistically significant (p=0.017) poorer response to splenectomy in the patients with steroid-resistant ITP.Conclusion. Splenectomy is effective and safe irrespective of HIV status and remains an appropriate  second-line treatment for ITP. Further research is needed to corroborate our finding of lower response in patients who are steroid-resistant, as this might be a subgroup of patients who may benefit from  thrombopoietin agonists as second-line therapy

Performance of prototypes for the ALICE electromagnetic calorimeter

The performance of prototypes for the ALICE electromagnetic sampling calorimeter has been studied in test beam measurements at FNAL and CERN. A $4\times4$ array of final design modules showed an energy resolution of about 11% /$\sqrt{E(\mathrm{GeV})}$ $\oplus$ 1.7 % with a uniformity of the response to electrons of 1% and a good linearity in the energy range from 10 to 100 GeV. The electromagnetic shower position resolution was found to be described by 1.5 mm $\oplus$ 5.3 mm /$\sqrt{E \mathrm{(GeV)}}$. For an electron identification efficiency of 90% a hadron rejection factor of $>600$ was obtained.Comment: 10 pages, 10 figure

Measurements of double-helicity asymmetries in inclusive J/ψJ/\psi production in longitudinally polarized p+pp+p collisions at s=510\sqrt{s}=510 GeV

We report the double helicity asymmetry, $A_{LL}^{J/\psi}$, in inclusive $J/\psi$ production at forward rapidity as a function of transverse momentum $p_T$ and rapidity $|y|$. The data analyzed were taken during $\sqrt{s}=510$ GeV longitudinally polarized $p$$+$$p$ collisions at the Relativistic Heavy Ion Collider (RHIC) in the 2013 run using the PHENIX detector. At this collision energy, $J/\psi$ particles are predominantly produced through gluon-gluon scatterings, thus $A_{LL}^{J/\psi}$ is sensitive to the gluon polarization inside the proton. We measured $A_{LL}^{J/\psi}$ by detecting the decay daughter muon pairs $\mu^+ \mu^-$ within the PHENIX muon spectrometers in the rapidity range $1.2<|y|<2.2$. In this kinematic range, we measured the $A_{LL}^{J/\psi}$ to be $0.012 \pm 0.010$~(stat)~$\pm$~$0.003$(syst). The $A_{LL}^{J/\psi}$ can be expressed to be proportional to the product of the gluon polarization distributions at two distinct ranges of Bjorken $x$: one at moderate range $x \approx 0.05$ where recent RHIC data of jet and $\pi^0$ double helicity spin asymmetries have shown evidence for significant gluon polarization, and the other one covering the poorly known small-$x$ region $x \approx 2\times 10^{-3}$. Thus our new results could be used to further constrain the gluon polarization for $x< 0.05$.Comment: 335 authors, 10 pages, 4 figures, 3 tables, 2013 data. Version accepted for publication by Phys. Rev. D. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm

Azimuthally anisotropic emission of low-momentum direct photons in Au++Au collisions at sNN=200\sqrt{s_{_{NN}}}=200 GeV

The PHENIX experiment at the Relativistic Heavy Ion Collider has measured 2nd and 3rd order Fourier coefficients of the azimuthal distributions of direct photons emitted at midrapidity in Au$+$Au collisions at $\sqrt{s_{_{NN}}}=200$ GeV for various collision centralities. Combining two different analysis techniques, results were obtained in the transverse momentum range of $0.4<p_{T}<4.0$ GeV/$c$. At low $p_T$ the second-order coefficients, $v_2$, are similar to the ones observed in hadrons. Third order coefficients, $v_3$, are nonzero and almost independent of centrality. These new results on $v_2$ and $v_3$, combined with previously published results on yields, are compared to model calculations that provide yields and asymmetries in the same framework. Those models are challenged to explain simultaneously the observed large yield and large azimuthal anisotropies.Comment: 552 authors, 15 pages, 9 figures, 3 tables, 2007 and 2010 data. v2 is version accepted for publication by Phys. Rev. C. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm

J/psi suppression at forward rapidity in Au+Au collisions at sqrt(s_NN)=39 and 62.4 GeV

We present measurements of the J/psi invariant yields in sqrt(s_NN)=39 and 62.4 GeV Au+Au collisions at forward rapidity (1.2<|y|<2.2). Invariant yields are presented as a function of both collision centrality and transverse momentum. Nuclear modifications are obtained for central relative to peripheral Au+Au collisions (R_CP) and for various centrality selections in Au+Au relative to scaled p+p cross sections obtained from other measurements (R_AA). The observed suppression patterns at 39 and 62.4 GeV are quite similar to those previously measured at 200 GeV. This similar suppression presents a challenge to theoretical models that contain various competing mechanisms with different energy dependencies, some of which cause suppression and others enhancement.Comment: 365 authors, 10 pages, 11 figures, 4 tables. Submitted to Phys. Rev. C. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm