83 research outputs found

    Longitudinal double-spin asymmetry and cross section for inclusive neutral pion production at midrapidity in polarized proton collisions at sqrt(s) = 200 GeV

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    We report a measurement of the longitudinal double-spin asymmetry A_LL and the differential cross section for inclusive Pi0 production at midrapidity in polarized proton collisions at sqrt(s) = 200 GeV. The cross section was measured over a transverse momentum range of 1 < p_T < 17 GeV/c and found to be in good agreement with a next-to-leading order perturbative QCD calculation. The longitudinal double-spin asymmetry was measured in the range of 3.7 < p_T < 11 GeV/c and excludes a maximal positive gluon polarization in the proton. The mean transverse momentum fraction of Pi0's in their parent jets was found to be around 0.7 for electromagnetically triggered events.Comment: 6 pages, 3 figures, submitted to Phys. Rev. D (RC

    Human hips, breasts and buttocks: Is fat deceptive?

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    In humans, reproductive-age females, unlike other ages and classes of individuals, deposit fat preferentially on the breasts, hips, and buttocks. This suggests that such fat deposition is a deceptive sexual signal, mimicking other signals of high reproductive value and potential.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26924/1/0000490.pd

    Measurement of jet suppression in central Pb-Pb collisions at root s(NN)=2.76 TeV

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    The transverse momentum(p(T)) spectrum and nuclear modification factor (R-AA) of reconstructed jets in 0-10% and 10-30% central Pb-Pb collisions at root s(NN) = 2.76 TeV were measured. Jets were reconstructed using the anti-k(T) jet algorithm with a resolution parameter of R = 0.2 from charged and neutral particles, utilizing the ALICE tracking detectors and Electromagnetic Calorimeter (EMCal). The jet p(T) spectra are reported in the pseudorapidity interval of \eta(jet)\ 5 GeV/c to suppress jets constructed from the combinatorial background in Pb-Pb collisions. The leading charged particle requirement applied to jet spectra both in pp and Pb-Pb collisions had a negligible effect on the R-AA. The nuclear modification factor R-AA was found to be 0.28 +/- 0.04 in 0-10% and 0.35 +/- 0.04 in 10-30% collisions, independent of p(T), jet within the uncertainties of the measurement. The observed suppression is in fair agreement with expectations from two model calculations with different approaches to jet quenching. (C) 2015 CERN for the benefit of the ALICE Collaboration. Published by Elsevier B.V.Peer reviewe

    Event-plane-dependent Dihadron Correlations With Harmonic Vn Subtraction In Au + Au Collisions At S Nn =200 Gev

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    STAR measurements of dihadron azimuthal correlations (Δφ) are reported in midcentral (20-60%) Au+Au collisions at sNN=200 GeV as a function of the trigger particle's azimuthal angle relative to the event plane, φs=|φt-ψEP|. The elliptic (v2), triangular (v3), and quadratic (v4) flow harmonic backgrounds are subtracted using the zero yield at minimum (ZYAM) method. The results are compared to minimum-bias d+Au collisions. It is found that a finite near-side (|Δφ|π/2) correlation shows a modification from d+Au data, varying with φs. The modification may be a consequence of path-length-dependent jet quenching and may lead to a better understanding of high-density QCD. © 2014 American Physical Society.894DOE; U.S. Department of EnergyArsene, I., (2005) Nucl. Phys. A, 757, p. 1. , (BRAHMS Collaboration), () NUPABL 0375-9474 10.1016/j.nuclphysa.2005.02. 130;Back, B.B., (2005) Nucl. Phys. A, 757, p. 28. , (PHOBOS Collaboration), () NUPABL 0375-9474 10.1016/j.nuclphysa.2005.03. 084;Adams, J., (2005) Nucl. Phys. A, 757, p. 102. , (STAR Collaboration), () NUPABL 0375-9474 10.1016/j.nuclphysa.2005.03. 085;Adcox, K., (2005) Nucl. Phys. A, 757, p. 184. , (PHENIX Collaboration),. NUPABL 0375-9474 10.1016/j.nuclphysa.2005.03.086Heinz, U., Kolb, P.F., (2002) Nucl. Phys. A, 702, p. 269. , NUPABL 0375-9474 10.1016/S0375-9474(02)00714-5Wang, X.-N., Gyulassy, M., (1992) Phys. Rev. Lett., 68, p. 1480. , PRLTAO 0031-9007 10.1103/PhysRevLett.68.1480Adler, S., (2003) Phys. Rev. Lett., 91, p. 072301. , (PHENIX Collaboration), () PRLTAO 0031-9007 10.1103/PhysRevLett.91. 072301;Adams, J., (2003) Phys. Rev. Lett., 91, p. 072304. , (STAR Collaboration), () PRLTAO 0031-9007 10.1103/PhysRevLett.91.072304;Adler, C., (2003) Phys. Rev. Lett., 90, p. 082302. , (STAR Collaboration),. PRLTAO 0031-9007 10.1103/PhysRevLett.90.082302Adams, J., (2005) Phys. Rev. Lett., 95, p. 152301. , (STAR Collaboration), () PRLTAO 0031-9007 10.1103/PhysRevLett.95.152301;Aggarwal, M.M., (2010) Phys. Rev. C, 82, p. 024912. , (STAR Collaboration),. PRVCAN 0556-2813 10.1103/PhysRevC.82.024912Adams, J., (2004) Phys. Rev. Lett., 93, p. 252301. , (STAR Collaboration),. PRLTAO 0031-9007 10.1103/PhysRevLett.93.252301Poskanzer, A.M., Voloshin, S.A., (1998) Phys. Rev. C, 58, p. 1671. , PRVCAN 0556-2813 10.1103/PhysRevC.58.1671Alver, B., (2008) Phys. Rev. C, 77, p. 014906. , PRVCAN 0556-2813 10.1103/PhysRevC.77.014906Feng, A., (2008), Ph.D. thesis, Institute of Particle Physics, CCNU, (unpublished);Konzer, J., (2013), Ph.D. thesis, Purdue University, (unpublished)Agakishiev, H., (STAR Collaboration), arXiv:1010.0690Ackermann, K.H., (2003) Nucl. Instrum. Meth., A499, p. 624. , (STAR Collaboration),. NIMAER 0168-9002 10.1016/S0168-9002(02)01960-5Ackermann, K.H., (1999) Nucl. Phys. A, 661, p. 681. , (STAR Collaboration),. NUPABL 0375-9474 10.1016/S0375-9474(99)85117-3Adams, J., (2004) Phys. Rev. Lett., 92, p. 112301. , (STAR Collaboration),. PRLTAO 0031-9007 10.1103/PhysRevLett.92.112301Borghini, N., Dinh, P.M., Ollitrault, J.Y., (2000) Phys. Rev. C, 62, p. 034902. , PRVCAN 0556-2813 10.1103/PhysRevC.62.034902Adams, J., (2005) Phys. Rev. C, 72, p. 014904. , (STAR Collaboration),. PRVCAN 0556-2813 10.1103/PhysRevC.72.014904Abelev, B.I., (2009) Phys. Rev. C, 79, p. 034909. , (STAR Collaboration),. PRVCAN 0556-2813 10.1103/PhysRevC.79.034909Bielcikova, J., (2004) Phys. Rev C, 69, p. 021901. , (R) () PRVCAN 0556-2813 10.1103/PhysRevC.69.021901;Konzer, J., Wang, F., (2009) Nucl. Instrum. Meth., A606, p. 713. , NIMAER 0168-9002 10.1016/j.nima.2009.05.011Mishra, A.P., (2008) Phys. Rev. C, 77, p. 064902. , PRVCAN 0556-2813 10.1103/PhysRevC.77.064902;Alver, B., Roland, G., (2010) Phys. Rev. C, 81, p. 054905. , PRVCAN 0556-2813 10.1103/PhysRevC.81.054905Alver, B., Roland, G., (2010) Phys. Rev. C, 82, p. 039903. , 0556-2813 10.1103/PhysRevC.82.039903Xu, J., Ko, C.M., (2011) Phys. Rev. C, 84, p. 014903. , PRVCAN 0556-2813 10.1103/PhysRevC.84.014903Petersen, H., (2010) Phys. Rev. C, 82, p. 041901. , PRVCAN 0556-2813 10.1103/PhysRevC.82.041901Takahashi, J., (2009) Phys. Rev. Lett., 103, p. 242301. , PRLTAO 0031-9007 10.1103/PhysRevLett.103.242301;Andrade, R.P.G., (2012) Phys. Lett. B, 712, p. 226. , PYLBAJ 0370-2693 10.1016/j.physletb.2012.04.044;Qian, W.L., (2013) Phys. Rev. C, 87, p. 014904. , PRVCAN 0556-2813 10.1103/PhysRevC.87.014904Schenke, B., Jeon, S., Gale, C., (2011) Phys. Rev. Lett., 106, p. 042301. , PRLTAO 0031-9007 10.1103/PhysRevLett.106.042301;Qiu, Z., Heinz, U.W., (2011) Phys. Rev. C, 84, p. 024911. , PRVCAN 0556-2813 10.1103/PhysRevC.84.024911;Song, H., (2011) Phys. Rev. Lett., 106, p. 192301. , PRLTAO 0031-9007 10.1103/PhysRevLett.106.192301;Schenke, B., Jeon, S., Gale, C., (2012) Phys. Rev. C, 85, p. 024901. , PRVCAN 0556-2813 10.1103/PhysRevC.85.024901;Schenke, B., Tribedy, P., Venugopalan, R., (2012) Phys. Rev. Lett., 108, p. 252301. , PRLTAO 0031-9007 10.1103/PhysRevLett.108.252301Adare, A., (2011) Phys. Rev. Lett., 107, p. 252301. , (PHENIX Collaboration),. PRLTAO 0031-9007 10.1103/PhysRevLett.107.252301Adamczyk, L., (2013) Phys. Rev. C, 88, p. 014904. , (STAR Collaboration),. PRVCAN 0556-2813 10.1103/PhysRevC.88.014904Abelev, B.I., (2008) Phys. Rev. Lett., 101, p. 252301. , (STAR Collaboration),. PRLTAO 0031-9007 10.1103/PhysRevLett.101.252301Teaney, D., Yan, L., (2011) Phys. Rev. C, 83, p. 064904. , PRVCAN 0556-2813 10.1103/PhysRevC.83.064904Pandit, Y., (2013) J. Phys. Conf. Ser., 446, p. 012012. , (STAR Collaboration),. 1742-6596 10.1088/1742-6596/446/1/012012Ajitanand, N.N., (2005) Phys. Rev. C, 72, p. 011902. , PRVCAN 0556-2813 10.1103/PhysRevC.72.011902Agakishiev, G., (2012) Phys. Rev. C, 86, p. 064902. , (STAR Collaboration),. PRVCAN 0556-2813 10.1103/PhysRevC.86.064902Adler, C., (2002) Phys. Rev. C, 66, p. 034904. , (STAR Collaboration),. PRVCAN 0556-2813 10.1103/PhysRevC.66.034904Abelev, B.I., (2009) Phys. Rev. C, 80, p. 064912. , (STAR Collaboration), () PRVCAN 0556-2813 10.1103/PhysRevC.80.064912;Abelev, B.I., (2010) Phys. Rev. Lett., 105, p. 022301. , PRLTAO 0031-9007 10.1103/PhysRevLett.105.022301Adler, S.S., (2006) Phys. Rev. Lett., 97, p. 052301. , (PHENIX Collaboration), () PRLTAO 0031-9007 10.1103/PhysRevLett.97. 052301;Adare, A., (2008) Phys. Rev. C, 78, p. 014901. , (PHENIX Collaboration),. PRVCAN 0556-2813 10.1103/PhysRevC.78.014901Stoecker, H., (2005) Nucl. Phys. A, 750, p. 121. , NUPABL 0375-9474 10.1016/j.nuclphysa.2004.12.074;Casalderrey-Solana, J., Shuryak, E.V., Teaney, D., (2005) J. Phys. Conf. Ser., 27, p. 22. , 1742-6588 10.1088/1742-6596/27/1/003;Ruppert, J., Müller, B., (2005) Phys. Lett. B, 618, p. 123. , PYLBAJ 0370-2693 10.1016/j.physletb.2005.04.075Betz, B., (2010) Phys. Rev. Lett., 105, p. 222301. , PRLTAO 0031-9007 10.1103/PhysRevLett.105.222301;Ma, G.L., Wang, X.N., (2011) Phys. Rev. Lett., 106, p. 162301. , PRLTAO 0031-9007 10.1103/PhysRevLett.106.162301Abelev, B.I., (2009) Phys. Rev. Lett., 102, p. 052302. , (STAR Collaboration),. PRLTAO 0031-9007 10.1103/PhysRevLett.102.052302Adamczyk, L., (2014) Phys. Rev. Lett., 112, p. 122301. , (STAR Collaboration),. 10.1103/PhysRevLett.112.12230

    Fluctuations Of Charge Separation Perpendicular To The Event Plane And Local Parity Violation In S Nn = 200 Gev Au + Au Collisions At The Bnl Relativistic Heavy Ion Collider

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    Previous experimental results based on data (∼15×106 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 (57×106 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. © 2013 American Physical Society.886NRF-2012004024; National Research FoundationLee, T.D., Yang, C.N., (1956) Phys. Rev., 104. , 1, 254. 0031-899X PHRVAO 10.1103/PhysRev.104.254Vafa, C., Witten, E., (1984) Phys. Rev. Lett., 53. , 2, 535. 0031-9007 PRLTAO 10.1103/PhysRevLett.53.535Lee, T.D., (1973) Phys. Rev. D, 8. , 3, 1226. 0556-2821 10.1103/PhysRevD.8.1226Lee, T.D., Wick, G.C., (1974) Phys. Rev. D, 9. , 4, 2291. 0556-2821 10.1103/PhysRevD.9.2291Kharzeev, D., Parity violation in hot QCD: Why it can happen, and how to look for it (2006) Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 633 (2-3), pp. 260-264. , DOI 10.1016/j.physletb.2005.11.075, PII S0370269305017430Kharzeev, D., Zhitnitsky, A., (2007) Nucl. Phys. A, 797. , 6, 67. 0375-9474 NUPABL 10.1016/j.nuclphysa.2007.10.001Kharzeev, D., McLerran, L.D., Warringa, H.J., (2008) Nucl. Phys. A, 803. , 7, 227. 0375-9474 NUPABL 10.1016/j.nuclphysa.2008.02.298Fukushima, K., Kharzeev, D.E., Warringa, H.J., (2008) Phys. Rev. D, 78. , 8, 074033. 1550-7998 PRVDAQ 10.1103/PhysRevD.78.074033Abelev, B.I., (2009) Phys. Rev. Lett., 103. , 9 (STAR Collaboration), 251601. 0031-9007 PRLTAO 10.1103/PhysRevLett.103. 251601Abelev, B.I., (2010) Phys. Rev. C, 81. , 10 (STAR Collaboration), 054908. 0556-2813 PRVCAN 10.1103/PhysRevC.81. 054908Abelev, B.I., (2013) Phys. Rev. Lett., 110. , 11 (ALICE Collaboration), 012301. 0031-9007 PRLTAO 10.1103/PhysRevLett. 110.012301Ackermann, K.H., Adams, N., Adler, C., Ahammed, Z., Ahmad, S., Allgower, C., Amonett, J., Harris, J.W., STAR detector overview (2003) Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 499 (2-3), pp. 624-632. , DOI 10.1016/S0168-9002(02)01960-5Adams, J., Aggarwal, M.M., Ahammed, Z., Amonett, J., Anderson, B.D., Arkhipkin, D., Averichev, G.S., Bai, Y., Directed flow in Au+Au collisions at sNN=62.4 GeV (2006) Physical Review C - Nuclear Physics, 73 (3), pp. 1-7. , http://oai.aps.org/oai?verb=GetRecord&Identifier=oai:aps.org: PhysRevC.73.034903&metadataPrefix=oai_apsmeta_2, DOI 10.1103/PhysRevC.73.034903, 034903Adamczyk, L., (2012) Phys. Rev. Lett., 108. , 14 (STAR Collaboration), 202301. 0031-9007 PRLTAO 10.1103/PhysRevLett. 108.202301Voloshin, S.A., Parity violation in hot QCD: How to detect it (2004) Physical Review C - Nuclear Physics, 70 (5), pp. 0579011-0579012. , DOI 10.1103/PhysRevC.70.057901, 057901Poskanzer, A.M., Voloshin, S.A., Methods for analyzing anisotropic flow in relativistic nuclear collisions (1998) Physical Review C - Nuclear Physics, 58 (3), pp. 1671-1678. , DOI 10.1103/PhysRevC.58.1671Ollitrault, J.-Y., Poskanzer, A.M., Voloshin, S.A., (2009) Phys. Rev. C, 80. , 17, 014904. 0556-2813 PRVCAN 10.1103/PhysRevC.80.014904Pratt, S., Schlichting, S., Gavin, S., (2011) Phys. Rev. C, 84. , 18, 024909. 0556-2813 PRVCAN 10.1103/PhysRevC.84.024909Schlichting, S., Pratt, S., (2011) Phys. Rev. C, 83. , 19, 014913. 0556-2813 PRVCAN 10.1103/PhysRevC.83.014913Selyuzhenkov, I., Voloshin, S., (2008) Phys. Rev. C, 77. , 20, 034904. 0556-2813 PRVCAN 10.1103/PhysRevC.77.034904Kisiel, A., (2006) Comput. Phys. Commun., 174. , 21, 669. 0010-4655 CPHCBZ 10.1016/j.cpc.2005.11.010Bzdak, A., Koch, V., Liao, J., (2011) Phys. Rev. C, 83. , 22, 014905. 0556-2813 PRVCAN 10.1103/PhysRevC.83.014905Adams, J., Aggarwal, M.M., Ahammed, Z., Amonett, J., Anderson, B.D., Arkhipkin, D., Averichev, G.S., Grebenyuk, O., Azimuthal anisotropy in Au+Au collisions at sNN=200GeV (2005) Physical Review C - Nuclear Physics, 72 (1), pp. 1-23. , http://oai.aps.org/oai/?verb=ListRecords&metadataPrefix= oai_apsmeta_2&set=journal:PRC:72, DOI 10.1103/PhysRevC.72.014904, 014904Ray, R.L., Longacre, R.S., 24, arXiv:nucl-ex/0008009 and private communicationKopylov, G.I., Podgoretsky, M.I., Kopylov, G.I., Podgoretsky, M.I., (1972) Sov. J. Nucl. Phys., 15. , 25a, 219 ()25b, Phys. Lett. B. 50, 472 (1974) 0370-2693 PYLBAJ 10.1016/0370-2693(74)90263-925c, Sov. J. Part. Nucl. 20, 266 (1989)Goldhaber, G., Goldhaber, S., Lee, W., Pais, A., (1960) Phys. Rev., 120. , 26, 325. 0031-899X PHRVAO 10.1103/PhysRev.120.32

    Elliptic flow of identified hadrons in Pb-Pb collisions at 1asNN = 2.76 TeV

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    The elliptic flow coefficient (v2) of identified particles in Pb-Pb collisions at 1asNN = 2.76 TeV was measured with the ALICE detector at the Large Hadron Collider (LHC). The results were obtained with the Scalar Product method, a two-particle corre- lation technique, using a pseudo-rapidity gap of | 06\u3b7| > 0.9 between the identified hadron under study and the reference particles. The v2 is reported for \u3c0\ub1, K\ub1, K0S, p+p, \u3c6, \u39b+\u39b, \u39e 12+\u39e+ and \u3a9 12+\u3a9+ in several collision centralities. In the low transverse momentum (pT) region, pT 3 GeV/c

    Centrality dependence of inclusive J/\u3c8 production in p-Pb collisions at 1asNN = 5.02 TeV

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    We present a measurement of inclusive J/\u3c8 production in p-Pb collisions at 1asNN = 5.02TeV as a function of the centrality of the collision, as estimated from the energy deposited in the Zero Degree Calorimeters. The measurement is performed with the ALICE detector down to zero transverse momentum, pT, in the backward ( 124.46 < ycms < 122.96) and forward (2.03 < ycms < 3.53) rapidity intervals in the dimuon decay channel and in the mid-rapidity region ( 121.37 < ycms < 0.43) in the dielectron decay channel. The backward and forward rapidity intervals correspond to the Pb-going and p-going direction, respectively. The pT-differential J/\u3c8 production cross section at backward and forward rapidity is measured for several centrality classes, together with the corresponding average pT and pT2 values. The nuclear modification factor is presented as a function of centrality for the three rapidity intervals, and as a function of pT for several centrality classes at backward and forward rapidity. At mid- and forward rapidity, the J/\u3c8 yield is suppressed up to 40% compared to that in pp interactions scaled by the number of binary collisions. The degree of suppression increases towards central p-Pb collisions at forward rapidity, and with decreasing pT of the J/\u3c8. At backward rapidity, the nuclear modification factor is compatible with unity within the total uncertainties, with an increasing trend from peripheral to central p-Pb collisions

    Centrality dependence of high-pT D meson suppression in Pb-Pb collisions at 1asNN = 2.76 TeV

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    The nuclear modification factor, RAA, of the prompt charmed mesons D0, D+ and D 17+, and their antiparticles, was measured with the ALICE detector in Pb-Pb collisions at a centre-of-mass energy 1asNN = 2.76 TeV in two transverse momentum intervals, 5 < pT < 8GeV/c and 8 < pT < 16GeV/c, and in six collision centrality classes. The RAA shows a maximum suppression of a factor of 5\u20136 in the 10% most central collisions. The suppression and its centrality dependence are compatible within uncertainties with those of charged pions. A comparison with the RAA of non-prompt J/\u3c8 from B meson decays, measured by the CMS Collaboration, hints at a larger suppression of D mesons in the most central collisions
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