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

Observation of an Antimatter Hypernucleus

Nuclear collisions recreate conditions in the universe microseconds after the Big Bang. Only a very small fraction of the emitted fragments are light nuclei, but these states are of fundamental interest. We report the observation of antihypertritons-comprising an antiproton, an antineutron, and an antilambda hyperon-produced by colliding gold nuclei at high energy. Our analysis yields 70 +/- 17 antihypertritons (3/Lambda(H) over bar) and 157 +/- 30 hypertritons (H-3(Lambda)). The measured yields of H-3(Lambda) (3/Lambda(H) over bar) and He-3 ((3)(He) over bar) are similar, suggesting an equilibrium in coordinate and momentum space populations of up, down, and strange quarks and antiquarks, unlike the pattern observed at lower collision energies. The production and properties of antinuclei, and of nuclei containing strange quarks, have implications spanning nuclear and particle physics, astrophysics, and cosmology

Long range rapidity correlations and jet production in high energy nuclear collisions

The STAR Collaboration at the Relativistic Heavy Ion Collider presents a systematic study of high-transverse-momentum charged-di-hadron correlations at small azimuthal pair separation Delta phi in d+Au and central Au+Au collisions at s(NN)=200 GeV. Significant correlated yield for pairs with large longitudinal separation Delta eta is observed in central Au+Au collisions, in contrast to d+Au collisions. The associated yield distribution in Delta eta x Delta phi can be decomposed into a narrow jet-like peak at small angular separation which has a similar shape to that found in d+Au collisions, and a component that is narrow in Delta phi and depends only weakly on Delta eta, the "ridge." Using two systematically independent determinations of the background normalization and shape, finite ridge yield is found to persist for trigger p(t)>6 GeV/c, indicating that it is correlated with jet production. The transverse-momentum spectrum of hadrons comprising the ridge is found to be similar to that of bulk particle production in the measured range (2 < p(t)< 4 GeV/c)

An evaluation of the knowledge and needs of women with diabetes in relation to reproductive health; a focus group study

see paper for full list of authorsJet-medium interactions are studied via a multi-hadron correlation technique (called "2+1"), where a pair of back-to-back hadron triggers with large transverse momentum is used as a proxy for a di-jet. This work extends the previous analysis for nearly-symmetric trigger pairs with the highest momentum threshold of trigger hadron of 5 GeV/$c$ with the new calorimeter-based triggers with energy thresholds of up to 10 GeV and above. The distributions of associated hadrons are studied in terms of correlation shapes and per-trigger yields on each trigger side. In contrast with di-hadron correlation results with single triggers, the associated hadron distributions for back-to-back triggers from central Au+Au data at $\sqrt{s_{NN}}$=200 GeV show no strong modifications compared to d+Au data at the same energy. An imbalance in the total transverse momentum between hadrons attributed to the near-side and away-side of jet-like peaks is observed. The relative imbalance in the Au+Au measurement with respect to d+Au reference is found to increase with the asymmetry of the trigger pair, consistent with expectation from medium-induced energy loss effects. In addition, this relative total transverse momentum imbalance is found to decrease for softer associated hadrons. Such evolution indicates the energy missing at higher associated momenta is converted into softer hadrons

Event-plane-dependent dihadron correlations with harmonic v(n) subtraction in Au plus Au collisions at v root sNN=200 GeV

STAR measurements of dihadron azimuthal correlations (Lambda phi) are reported in midcentral (20-60%) Au + Au collisions at v root sNN = 200 GeV as a function of the trigger particle's azimuthal angle relative to the event plane, phi(s) = | phi(1) -psi(EP)|. The elliptic (v(2)), triangular (v(3)), and quadratic (v(4)) flow harmonic backgrounds are subtracted using the zero yield at mini + Au collisions. It is found that a finite near-side (| Delta phi | pi/2) correlation shows a modification from d+ Au data, varying with fs. The modification may be a consequence of path-length-dependent jet quenching and may lead to a better understanding of high-density QCD

Higher Moments of Net Proton Multiplicity Distributions at RHIC

200 GeV corresponding to baryon chemical potentials (mu(B)) between 200 and 20 MeV. Our measurements of the products kappa sigma(2) and S sigma, which can be related to theoretical calculations sensitive to baryon number susceptibilities and long-range correlations, are constant as functions of collision centrality. We compare these products with results from lattice QCD and various models without a critical point and study the root s(NN) dependence of kappa sigma(2). From the measurements at the three beam energies, we find no evidence for a critical point in the QCD phase diagram for mu(B) below 200 MeV

J/psi production at high transverse momenta in p plus p and Au plus Au collisions at root s(NN)=200 GeV

We report J/psi spectra for transverse momenta P-T > 5 GeV/c at mid-rapidity in p + p and Au + Au collisions at root s(NN) = 200 GeV. The inclusive J/psi spectrum and the extracted B-hadron feed-down are compared to models incorporating different production mechanisms. We observe significant suppression of the J/psi yields for p(T) > 5 GeV/c in 0-30% central Au + Au collisions relative to the p + p yield scaled by the number of binary nucleon-nucleon collisions in Au + Au collisions. In 30-60% mid-central collisions, no such suppression is observed. The level of suppression is consistently less than that of high-p(T) pi(+/-) and low-p(T) J/psi at RHIC and high-p(T) J/psi at the LHC. (C) 2013 Elsevier B.V. All rights reserved

J/psi production at high transverse momenta in p plus p and Au plus Au collisions at root s(NN)=200 GeV

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)We report J/psi spectra for transverse momenta P-T > 5 GeV/c at mid-rapidity in p + p and Au + Au collisions at root s(NN) = 200 GeV. The inclusive J/psi spectrum and the extracted B-hadron feed-down are compared to models incorporating different production mechanisms. We observe significant suppression of the J/psi yields for p(T) > 5 GeV/c in 0-30% central Au + Au collisions relative to the p + p yield scaled by the number of binary nucleon-nucleon collisions in Au + Au collisions. In 30-60% mid-central collisions, no such suppression is observed. The level of suppression is consistently less than that of high-p(T) pi(+/-) and low-p(T) J/psi at RHIC and high-p(T) J/psi at the LHC. (C) 2013 Elsevier B.V. All rights reserved.722416995562RHIC Operations Group and RCF at BNLNERSC Center at LBNLOpen Science Grid consortiumOffices of NP and HEP within the US DOE Office of ScienceUS NSFSloan FoundationDFG cluster of excellence 'Origin and Structure of the Universe' of GermanyCNRS/IN2P3Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Ministry of Ed. and Sci. of the Russian FederationNNSFCCASMoSTMoE of ChinaGAMSMT of the Czech RepublicFOMNWO of the NetherlandsDAEDSTCSIR of IndiaPolish Ministry of Sci. and Higher Ed.Korea National Research FoundationMinistry of Sci., Ed. and Sports of the Rep. of CroatiaRosAtom of RussiaFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Fluctuations of charge separation perpendicular to the event plane and local parity violation in root S-NN=200 GeV Au + Au collisions at the BNL Relativistic Heavy Ion Collider

Previous experimental results based on data (similar to 15 x 10(6) events) collected by the STAR detector at the BNL Relativistic Heavy Ion Collider suggest event-by-event charge-separation fluctuations perpendicular to the event plane in noncentral heavy-ion collisions. Here we present the correlator previously used split into its two component parts to reveal correlations parallel and perpendicular to the event plane. The results are from a high-statistics 200-GeV Au + Au collisions data set (57 x 10(6) events) collected by the STAR experiment. We explicitly count units of charge separation from which we find clear evidence for more charge-separation fluctuations perpendicular than parallel to the event plane. We also employ a modified correlator to study the possible P-even background in same- and opposite-charge correlations, and find that the P-even background may largely be explained by momentum conservation and collective motion