Highlights from PHENIX - II

This contribution highlights recent results from the PHENIX Collaboration at RHIC with emphasis on those obtained through lepton and photon measurements in PHENIX.Comment: 9 pages, 13 figures, presented at the 20th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions - "Quark Matter 2008", Jaipur, India, February 4-10, 200

J/psi production at RHIC-PHENIX

The J/psi is considered to be among the most important probes for the deconfined quark gluon plasma (QGP) created by relativistic heavy ion collisions. While the J/psi is thought to dissociate in the QGP by Debye color screening, there are competing effects from cold nuclear matter (CNM), feed-downs from excited charmonia (chi_c and psi') and bottom quarks, and regeneration from uncorrelated charm quarks. Measurements that can provide information to disentangle these effects are presented in this paper.Comment: 4 pages, 3 figures, conference proceedings: the 20th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions, Quark Matter 2008, Jaipur (India), 4-10 February 2008, submitted to J. Phys. G: Nuclear and Particle Physic

ϕ\phi meson production in dd++Au collisions at sNN=200\sqrt{s_{_{NN}}}=200 GeV

The PHENIX experiment has measured $\phi$ meson production in $d$$+$Au collisions at $\sqrt{s_{_{NN}}}=200$ GeV using the dimuon and dielectron decay channels. The $\phi$ meson is measured in the forward (backward) $d$-going (Au-going) direction, $1.2<y<2.2$ ($-2.2<y<-1.2$) in the transverse-momentum ($p_T$) range from 1--7 GeV/$c$, and at midrapidity $|y|<0.35$ in the $p_T$ range below 7 GeV/$c$. The $\phi$ meson invariant yields and nuclear-modification factors as a function of $p_T$, rapidity, and centrality are reported. An enhancement of $\phi$ meson production is observed in the Au-going direction, while suppression is seen in the $d$-going direction, and no modification is observed at midrapidity relative to the yield in $p$$+$$p$ collisions scaled by the number of binary collisions. Similar behavior was previously observed for inclusive charged hadrons and open heavy flavor indicating similar cold-nuclear-matter effects.Comment: 484 authors, 16 pages, 12 figures, 6 tables. v1 is the version accepted for publication in Phys. Rev. C. Data tables for the points plotted in the figures are given in the paper itsel

Point View in Bird and Flower Painting

在中国传统绘画中，点景是极其重要的一种表达方式。石涛所研究的绘画问题中，情感、理性、力量都是不可缺少的，如何恰当地运用这三者，却有可能导致完全不同的创作结果。而点景正是这三者的集合点，不仅要用心灵去感受自然对象的内在精神，不能因为对象的限制而使感受层次也受到限制，把眼睛之受升华为心理之受。在绘画作品中合理地运用点景能使画家的情感与物象更加融合，画家自身的主观感受在画面上得到充分的体现，以一种小的特殊表现符号流露出画家作品里表达的象征倾向和审美概念，对画面的构图及意境有着画龙点睛的作用。本文以花鸟画点景为研究对象，重点介绍了点景的表现与意义；进一步阐述了点景在传统花鸟画构成中的作用，着重论述其在...The “point view” is extremely important as a means of expression in the traditional Chinese painting. Emotion, rationality and power are essential in the Shi Tao studied painting, and how to properly use them may lead to the creation of a completely different result. For the reason that “point view” is a collection of these three points, shouldn’t we only use the soul to feel the inner spirit of n...学位：文学硕士院系专业：艺术教育学院美术系_美术学学号：1862007115166

The p38-Mediated Rapid Down-Regulation of Cell Surface gp130 Expression Impairs Interleukin-6 Signaling in the Synovial Fluid of Juvenile Idiopathic Arthritis Patients

Objective. Interleukin-6 (IL-6) signaling plays an important proinflammatory role, but this role is restricted by regulatory mechanisms that, for example, reduce the cell surface availability of the signaltransducing chain of the IL-6 receptor, gp130. The aim of this study was to determine whether the inflammatory environment in arthritic joints has an impact on monocytic gp130 surface expression and the extent to which regulatory processes in the synovial fluid (SF) can be reproduced in an in vitro model. Methods. Flow cytometry and live cell imaging were used to measure the cell surface expression and internalization of gp130. STAT-3 phosphorylation was monitored by flow cytometry and Western blotting. Results. In patients with juvenile idiopathic arthritis (JIA), levels of cell surface gp130 expression in SF monocytes were reduced compared to those in peripheral blood (PB) monocytes. These reduced levels were reproduced when PB monocytes from healthy donors were stim ulated with SF, and this reduction was dependent on p38 MAPK. The induction of p38 by IL-1 in PB monocytes interfered with IL-6 signaling due to the reduced cell surface expression of gp130. Conclusion. These results suggest that p38- mediated proinflammatory stimuli induce the downregulation of gp130 on monocytes and thus restrict gp130-mediated signal transduction. This regulatory mechanism could be of relevance to processes in the inflamed joints of patients with JIA

Photon-hadron jet correlations in p plus p and Au plus Au collisions at s(NN)=200 GeV

We report the observation at the Relativistic Heavy Ion Collider of suppression of back-to-back correlations in the direct photon+jet channel in Au+Au relative to p+p collisions. Two-particle correlations of direct photon triggers with associated hadrons are obtained by statistical subtraction of the decay photon-hadron (gamma-h) background. The initial momentum of the away-side parton is tightly constrained, because the parton-photon pair exactly balance in momentum at leading order in perturbative quantum chromodynamics, making such correlations a powerful probe of the in-medium parton energy loss. The away-side nuclear suppression factor, I(AA), in central Au+Au collisions, is 0.32 +/- 0.12(stat)+/- 0.09(syst) for hadrons of 3 < p(T)(h)< 5 in coincidence with photons of 5 < p(T)(gamma)< 15 GeV/c. The suppression is comparable to that observed for high-p(T) single hadrons and dihadrons. The direct photon associated yields in p+p collisions scale approximately with the momentum balance, z(T)equivalent to p(T)(h)/p(T)(gamma), as expected for a measurement of the away-side parton fragmentation function. We compare to Au+Au collisions for which the momentum balance dependence of the nuclear modification should be sensitive to the path-length dependence of parton energy loss.Office of Science of the Department of Energy (DOE)National Science Foundation (NSF)Renaissance Technologies LLCAbilene Christian University Research CouncilResearch Foundation of SUNYDean of the College of Arts and Sciences, Vanderbilt University (USA)Ministry of Education, Culture, Sports, Science, and Technology (MEXT), JapanJSPS - Japan Society for the Promotion of Science (Japan)Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq)Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP) (Brazil)NSFC Natural Science Foundation of China (People's Republic of China)MSMT Ministry of Education, Youth and Sports (Czech Republic)Centre National de la Recherche Scientifique - CNRSCEA Commissariat a l'Energie Atomique(CNRS/IN2P3) Institut National de Physique Nucleaire et de Physique des Particules (France)Ministry of Industry, Science and TekhnologiesBMBF - Bundesministerium fur Bildung und Forschung, Germany(DAAD) Deutscher Akademischer Austausch Dienst, GermanyAlexander von Humboldt Stiftung (Germany)OTKA Hungarian National Science FundOTKA (Hungary)(DAE) Department of Atomic Energy, IndiaISF - Israel Science Foundation (Israel)Korea Research Foundation (KRF) and Korea Science and Engineering Foundation (KOSEF), KoreaMinistry of Education and ScienceRAS Russia Academy of Sciences, FAAE Federal Agency of Atomic Energy (Russia)Wallenberg Foundation (Sweden)CRDF US Civilian Research and Development Foundation for the Independent States of the Former Soviet UnionUS-Hungarian Fulbright Foundation for Educational Exchange,(BSF) US-Israel Binational Science Foundatio

Nuclear modification factors of phi mesons in d plus Au, Cu plus Cu, and Au plus Au collisions at root s(NN)=200 GeV

The PHENIX experiment at the Relativistic Heavy Ion Collider has performed systematic measurements of phi meson production in the K(+)K(-) decay channel at midrapidity in p + p, d + Au, Cu + Cu, and Au + Au collisions at root s(NN) = 200 GeV. Results are presented on the phi invariant yield and the nuclear modification factor R(AA) for Au + Au and Cu + Cu, and R(dA) for d + Au collisions, studied as a function of transverse momentum (1 < p(T) < 7 GeV/c) and centrality. In central and midcentral Au + Au collisions, the R(AA) of phi exhibits a suppression relative to expectations from binary scaled p + p results. The amount of suppression is smaller than that of the pi(0) and the. in the intermediate p(T) range (2-5 GeV/c), whereas, at higher p(T), the phi, pi(0), and. show similar suppression. The baryon (proton and antiproton) excess observed in central Au + Au collisions at intermediate p(T) is not observed for the phi meson despite the similar masses of the proton and the phi. This suggests that the excess is linked to the number of valence quarks in the hadron rather than its mass. The difference gradually disappears with decreasing centrality, and, for peripheral collisions, the R(AA) values for both particle species are consistent with binary scaling. Cu + Cu collisions show the same yield and suppression as Au + Au collisions for the same number of N(part). The R(dA) of phi shows no evidence for cold nuclear effects within uncertainties.Office of Nuclear Physics in the Office of Science of the Department of Energy (DOE)National Science Foundation (NSF)Abilene Christian University Research CouncilResearch Foundation of SUNYCollege of Arts and Sciences, Vanderbilt University (USA)Ministry of Education, Culture, Sports, Science, and Technology (MEXT), JapanJSPS - Japan Society for the Promotion of Science (Japan)Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq)Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP) (Brazil)NSFC Natural Science Foundation of China (People's Republic of China)MSMT Ministry of Education, Youth and Sports (Czech Republic)Centre National de la Recherche Scientifique - CNRSCEA Commissariat a l'Energie Atomique(CNRS/IN2P3) Institut National de Physique Nucleaire et de Physique des Particules (France)Ministry of Industry, Science and TekhnologiesBMBF - Bundesministerium fur Bildung und Forschung, Germany(DAAD) Deutscher Akademischer Austausch Dienst and Alexander von Humboldt Stiftung (Germany)Hungarian National Science Fund, OTKA (Hungary)(DAE) Department of Atomic Energy and (DST) Department of Science and Technology, IndiaISF - Israel Science Foundation (Israel)National Research Foundation (NRF), KoreaMinistry of Education and ScienceRAS Russia Academy of SciencesFAAE Federal Agency of Atomic Energy (Russia)VR (Sweden)Wallenberg Foundation (Sweden)CRDF US Civilian Research and Development Foundation for the Independent States of the Former Soviet UnionUS-Hungarian Fulbright Foundation for Educational Exchange(BSF) US-Israel Binational Science Foundatio

Beam Energy and Centrality Dependence of Direct-Photon Emission from Ultrarelativistic Heavy-Ion Collisions

International audienceThe PHENIX collaboration presents first measurements of low-momentum (0.41  GeV/c) direct-photon yield dNγdir/dη is a smooth function of dNch/dη and can be well described as proportional to (dNch/dη)α with α≈1.25. This scaling behavior holds for a wide range of beam energies at the Relativistic Heavy Ion Collider and the Large Hadron Collider, for centrality selected samples, as well as for different A+A collision systems. At a given beam energy, the scaling also holds for high pT (>5  GeV/c), but when results from different collision energies are compared, an additional sNN-dependent multiplicative factor is needed to describe the integrated-direct-photon yield