Azimuthal Charged-Particle Correlations and Possible Local Strong Parity Violation

Parity-odd domains, corresponding to nontrivial topological solutions of the QCD vacuum, might be created during relativistic heavy-ion collisions. These domains are predicted to lead to charge separation of quarks along the system’s orbital momentum axis. We investigate a three-particle azimuthal correlator which is a P even observable, but directly sensitive to the charge separation effect. We report measurements of charged hadrons near center-of-mass rapidity with this observable in Au+Au and Cu+Cu collisions at √sNN=200  GeV using the STAR detector. A signal consistent with several expectations from the theory is detected. We discuss possible contributions from other effects that are not related to parity violation

Acupuncture in migraine prevention - A randomized sham controlled study with 6-months posttreatment follow-up

Objective: To assess the efficacy of acupuncture in migraine prophylaxis. Methods: Thirty-seven patients with migraine were enrolled in a randomized control trial at the Headache clinic located in a University Hospital. Real and sham acupuncture groups received 16 acupuncture sessions over 3 months. Treatment was individualized in the real acupuncture group and minimal acupuncture was used in the sham group. The primary end point was the percentage of patients with a >= 50% reduction in their migraine attack frequency in the second, third, fourth, fifth, and sixth (months) compared with the first one (baseline period). Primary and secondary end points were measured comparing headache diaries. Results: Real acupuncture group showed improvement with significant differences compared with the sham acupuncture group in the primary efficacy end point (P = 0.021) at the second month of the treatment. Differences also appeared in 2 secondary end points: number of days with migraine per month (P = 0.007) in the second month and the percentage of patients with >= 40% reduction in migraine attack frequency in the first (P = 0.044) and second months (P = 0.004) of the treatment. These differences disappeared in the third (last) month of the treatment as a consequence of the high improvement of the sham acupuncture group. Comparisons within each group showed that several migraine parameters evaluated improved significantly in both groups. Conclusions: Individualized treatment based on traditional Chinese medicine plays a role in preventing migraine attacks. Nevertheless, sham acupuncture had similar effects. Major conclusions were limited by the small sample sizes however the observed trends may contribute to design future trials.2429810

J/psi production at low p(T) in Au plus Au and Cu plus Cu collisions at root s(NN)=200 GeV with the STAR detector

The J/psi p(T) spectrum and nuclear modification factor (R-AA) are reported for p(T) < 5 GeV/c and vertical bar y vertical bar < 1 from 0% to 60% central Au + Au and Cu + Cu collisions at root s(NN) = 200 GeV at STAR. A significant suppression of p(T) - integrated J/psi production is observed in central Au + Au events. The Cu + Cu data are consistent with no suppression, although the precision is limited by the available statistics. R-AA in Au + Au collisions exhibits a strong suppression at low transverse momentum and gradually increases with p(T). The data are compared to high-p(T) STAR results and previously published BNL Relativistic Heavy Ion Collider results. Comparing with model calculations, it is found that the invariant yields at low p(T) are significantly above hydrodynamic flow predictions but are consistent with models that include color screening and regeneration

J/psi polarization in p plus p collisions at root s=200 GeV in STAR

We report on a polarization measurement of inclusive J/psi mesons in the di-electron decay channel at mid-rapidity at 2 < p(T) < 6 GeV/c in p + p collisions at root s = 200 GeV. Data were taken with the STAR detector at RHIC. The J/psi polarization measurement should help to distinguish between different models of the J/psi production mechanism since they predict different p(T) dependences of the J/psi polarization. In this analysis, J/psi is studied in the helicity frame. The polarization parameter lambda(theta) measured at RHIC becomes smaller towards high p(T), indicating more longitudinal J/psi polarization as p(T) increases. The result is compared with predictions of presently available models. (C) 2014 The Authors. Published by Elsevier B.V

Beam Energy Dependence of Moments of the Net-Charge Multiplicity Distributions in Au plus Au Collisions at RHIC

We report the first measurements of the moments-mean (M), variance (sigma(2)), skewness (S), and kurtosis (kappa)-of the net-charge multiplicity distributions at midrapidity in Au + Au collisions at seven energies, ranging from root s(NN) = 7.7 to 200 GeV, as a part of the Beam Energy Scan program at RHIC. The moments are related to the thermodynamic susceptibilities of net charge, and are sensitive to the location of the QCD critical point. We compare the products of the moments, sigma(2)/M, S sigma, and kappa sigma(2), with the expectations from Poisson and negative binomial distributions (NBDs). The S sigma values deviate from the Poisson baseline and are close to the NBD baseline, while the kappa sigma(2) values tend to lie between the two. Within the present uncertainties, our data do not show nonmonotonic behavior as a function of collision energy. These measurements provide a valuable tool to extract the freeze-out parameters in heavy-ion collisions by comparing with theoretical models

Jet-Hadron Correlations in root s(NN)=200 GeV p plus p and Central Au plus Au Collisions

Azimuthal angular correlations of charged hadrons with respect to the axis of a reconstructed (trigger) jet in Au + Au and p + p collisions at root s(NN) = 200 GeV in STAR are presented. The trigger jet population in Au + Au collisions is biased toward jets that have not interacted with the medium, allowing easier matching of jet energies between Au + Au and p + p collisions while enhancing medium effects on the recoil jet. The associated hadron yield of the recoil jet is significantly suppressed at high transverse momentum (p(T)(assoc)) and enhanced at low p(T)(assoc) in 0%-20% central Au + Au collisions compared to p + p collisions, which is indicative of medium-induced parton energy loss in ultrarelativistic heavy-ion collisions

Measurement of charge multiplicity asymmetry correlations in high-energy nucleus-nucleus collisions at root S-NN=200 GeV

A study is reported of the same-and opposite-sign charge-dependent azimuthal correlations with respect to the event plane in Au+ Au collisions at root(S)(NN) = 200 GeV. The charge multiplicity asymmetries between the up/down and left/right hemispheres relative to the event plane are utilized. The contributions from statistical fluctuations and detector effects were subtracted from the (co-) variance of the observed charge multiplicity asymmetries. In the mid-to most-central collisions, the same- (opposite-) sign pairs are preferentially emitted in back-to-back (aligned on the same-side) directions. The charge separation across the event plane, measured by the difference, Delta, between the like-and unlike-sign up/down-left/right correlations, is largest near the event plane. The difference is found to be proportional to the event-by-event final-state particle ellipticity (via the observed second order harmonic nu(obs)(2)), where Delta = [ 1.3 +/- 1.4( stat)(-1.0)(+4.0)(syst)] x 10(-5) + [3.2 +/- 0.2(stat)(- 0.3)(+0.4)(syst)] x 10(-3)v(2)(obs) for 20- 40% Au + Au collisions. The implications for the proposed chiral magnetic effect are discussed

Suppression of Upsilon production in d plus Au and Au plus Au collisions at root S-NN=200 GeV

We report measurements of Upsilon meson production in p + p, d + Au, and Au + Au collisions using the STAR detector at RHIC. We compare the Upsilon yield to the measured cross section in p + p collisions in order to quantify any modifications of the yield in cold nuclear matter using d + Au data and in hot nuclear matter using Au + Au data separated into three centrality classes. Our p + p measurement is based on three times the statistics of our previous result. We obtain a nuclear modification factor for Upsilon (1S + 2S + 3S) in the rapidity range vertical bar y vertical bar < 1 in d + Au collisions of R-dAu = 0.79 +/- 0.24(stat.) +/- 0.03(syst.) +/- 0.10(p + p syst.). A comparison with models including shadowing and initial state parton energy loss indicates the presence of additional cold-nuclear matter suppression. Similarly, in the top 10% most-central Au + Au collisions, we measure a nuclear modification factor of R-AA = 0.49 +/- 0.1(stat.) +/- 0.02(syst.) +/- 0.06(p + p syst.), which is a larger suppression factor than that seen in cold nuclear matter. Our results are consistent with complete suppression of excited-state Upsilon mesons in Au + Au collisions. The additional suppression in Au + Au is consistent with the level expected in model calculations that include the presence of a hot, deconfined Quark-Gluon Plasma. However, understanding the suppression seen in d + Au is still needed before any definitive statements about the nature of the suppression in Au + Au can be made735127137CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPRHIC Operations Group; NERSC Center at LBNL; KISTI Center in Korea; Open Science Grid consortium; National Science Foundation (NSF); Centre National de la Recherche Scientifique (CNRS); Ministry of Education and Science, Russian Federation; National Natural Science Foundation of China (NSFC); Chinese Academy of Sciences; Korean Research Foundation, GA; Ministry of Education, Youth & Sports - Czech Republic; FIAS of Germany; Department of Atomic Energy (DAE); Department of Science & Technology (India); Council of Scientific & Industrial Research (CSIR) - India; National Science Center, Poland; RosAtom of Russia ; RCF at BNL; United States Department of Energy (DOE); United States Department of Energy (DOE); Ministry of Education, China; Ministry of Science and Technology, China; Ministry of Science, Education and Sports, Republic of Croatia; National Science Foundation (NSF); NSF - Directorate for Mathematical & Physical Sciences (MPS