共查询到20条相似文献,搜索用时 625 毫秒
1.
Alver B Back BB Baker MD Ballintijn M Barton DS Betts RR Bindel R Busza W Chai Z Chetluru V García E Gburek T Gulbrandsen K Hamblen J Harnarine I Henderson C Hofman DJ Hollis RS Hołyński R Holzman B Iordanova A Kane JL Kulinich P Kuo CM Li W Lin WT Loizides C Manly S Mignerey AC Nouicer R Olszewski A Pak R Reed C Richardson E Roland C Roland G Sagerer J Sedykh I Smith CE Stankiewicz MA Steinberg P Stephans GS Sukhanov A Szostak A Tonjes MB Trzupek A van Nieuwenhuizen GJ Vaurynovich SS Verdier R 《Physical review letters》2006,96(21):212301
We present transverse momentum distributions of charged hadrons produced in Cu + Cu collisions at square root of SNN = 62.4 and 200 GeV. The spectra are measured for transverse momenta of 0.25 < pT < 5.0 GeV/c at square root of SNN = 62.4 GeV and 0.25 < pT < 7.0 GeV/c at square root of SNN = 200 GeV, in a pseudorapidity range of 0.2 < eta < 1.4. The nuclear modification factor R(AA) is calculated relative to p + p data at both collision energies as a function of collision centrality. At a given collision energy and fractional cross section, R(AA) is observed to be systematically larger in Cu + Cu collisions compared to Au + Au. However, for the same number of participating nucleons, R(AA) is essentially the same in both systems over the measured range of pT, in spite of the significantly different geometries of the Cu + Cu and Au + Au systems. 相似文献
2.
Adler SS Afanasiev S Aidala C Ajitanand NN Akiba Y Al-Jamel A Alexander J Aoki K Aphecetche L Armendariz R Aronson SH Atomssa ET Averbeck R Awes TC Babintsev V Baldisseri A Barish KN Barnes PD Bassalleck B Bathe S Batsouli S Baublis V Bauer F Bazilevsky A Belikov S Bjorndal MT Boissevain JG Borel H Brooks ML Brown DS Bruner N Bucher D Buesching H Bumazhnov V Bunce G Burward-Hoy JM Butsyk S Camard X Chand P Chang WC Chernichenko S Chi CY Chiba J Chiu M Choi IJ Choudhury RK Chujo T Cianciolo V 《Physical review letters》2006,96(1):012304
J/psi production in d + Au and p + p collisions at square root of S(NN) = 200 GeV has been measured by the PHENIX experiment at rapidities -2.2 < y < +2.4. The cross sections and nuclear dependence of J/psi production versus rapidity, transverse momentum, and centrality are obtained and compared to lower energy p + A results and to theoretical models. The observed nuclear dependence in d + Au collisions is found to be modest, suggesting that the absorption in the final state is weak and the shadowing of the gluon distributions is small and consistent with Dokshitzer-Gribov-Lipatov-Altarelli-Parisi-based parametrizations that fit deep-inelastic scattering and Drell-Yan data at lower energies. 相似文献
3.
We present Φ meson production in Cu+Cu and Au+Au collisions measured by the STAR experiment at RHIC.The hadronic decay mode Φ→K~+K~- is used in the analysis.The yields for Φ meson in Cu+Cu and Au+Au collisions at a given beam energy are scaled by the number of participant.The N_(part) normalized Φ meson yields in heavy ion collisions over those from p+p collisions are larger than 1 and increase with collision energy.These results suggest that the source of enhancement of strange hadrons is related to the formation of a dense medium in high energy heavy ion collisions and can not be only due to canonical suppression of their production in smaller systems.We also present STAR results on the Φ meson elliptic flow υ_2 from 2~(1/SNN)=200 GeV Cu+Cu at RHIC.The elliptic flow in Cu+Cu system that has the similar relative magnitude and qualitative features as that in Au+Au system.The observations imply the hot and dense matter with partonic collectivity has been formed in heavy ion collisions at RHIC.However,eccentrality normalized υ_2,υ_2/(n_qε_(part)) is lower for Cu+Cu than for Au+Au collisions at 200 GeV.So this might indicate thermalization has not been reached in 200 GeV Cu+Cu collisions. 相似文献
4.
Adare A Afanasiev S Aidala C Ajitanand NN Akiba Y Al-Bataineh H Alexander J Aoki K Aphecetche L Armendariz R Aronson SH Asai J Atomssa ET Averbeck R Awes TC Azmoun B Babintsev V Bai M Baksay G Baksay L Baldisseri A Barish KN Barnes PD Bassalleck B Basye AT Bathe S Batsouli S Baublis V Baumann C Bazilevsky A Belikov S Bennett R Berdnikov A Berdnikov Y Bickley AA Boissevain JG Borel H Boyle K Brooks ML Buesching H Bumazhnov V Bunce G Butsyk S Camacho CM Campbell S Chang BS Chang WC Charvet JL 《Physical review letters》2008,101(16):162301
Neutral pion transverse momentum (p(T)) spectra at midrapidity (|y| less than or approximately 0.35) were measured in Cu+Cu collisions at sqrt[s(NN)]=22.4, 62.4, and 200 GeV. Relative to pi_(0) yields in p+p collisions scaled by the number of inelastic nucleon-nucleon collisions (N(coll) the pi_(0) yields for p(T) more than or approximately 2 GeV/c in central Cu+Cu collisions are suppressed at 62.4 and 200 GeV whereas an enhancement is observed at 22.4 GeV. A comparison with a jet-quenching model suggests that final state parton energy loss dominates in central Cu+Cu collisions at 62.4 and 200 GeV, while the enhancement at 22.4 GeV is consistent with nuclear modifications in the initial state alone. 相似文献
5.
Adare A Afanasiev S Aidala C Ajitanand NN Akiba Y Al-Bataineh H Alexander J Al-Jamel A Aoki K Aphecetche L Armendariz R Aronson SH Asai J Atomssa ET Averbeck R Awes TC Azmoun B Babintsev V Baksay G Baksay L Baldisseri A Barish KN Barnes PD Bassalleck B Bathe S Batsouli S Baublis V Bauer F Bazilevsky A Belikov S Bennett R Berdnikov Y Bickley AA Bjorndal MT Boissevain JG Borel H Boyle K Brooks ML Brown DS Bucher D Buesching H Bumazhnov V Bunce G Burward-Hoy JM Butsyk S Campbell S Chai JS Chang BS 《Physical review letters》2007,98(23):232301
The PHENIX experiment at the BNL Relativistic Heavy Ion Collider (RHIC) has measured J/psi production for rapidities -2.2相似文献
6.
Adare A Afanasiev S Aidala C Ajitanand NN Akiba Y Al-Bataineh H Alexander J Aoki K Aphecetche L Armendariz R Aronson SH Asai J Atomssa ET Averbeck R Awes TC Azmoun B Babintsev V Baksay G Baksay L Baldisseri A Barish KN Barnes PD Bassalleck B Bathe S Batsouli S Baublis V Bazilevsky A Belikov S Bennett R Berdnikov Y Bickley AA Boissevain JG Borel H Boyle K Brooks ML Buesching H Bumazhnov V Bunce G Butsyk S Campbell S Chang BS Charvet JL Chernichenko S Chiba J Chi CY Chiu M Choi IJ Chujo T Chung P 《Physical review letters》2007,98(23):232002
J/psi production in p+p collisions at square root s=200 GeV has been measured by the PHENIX experiment at the BNL Relativistic Heavy Ion Collider over a rapidity range of -2.2相似文献
7.
G. I. Veres 《Indian Journal of Physics》2011,85(7):1015-1019
Charged particle pseudorapidity distributions are presented from the PHOBOS experiment at RHIC, measured in Au+Au and Cu+Cu
collisions at ?{sNN }\sqrt {s_{NN} } =19.6, 22.4, 62.4, 130 and 200 GeV, as a function of collision centrality. The presentation includes the recently analyzed
Cu+Cu data at 22.4 GeV. The measurements were made by the same detector setup over a broad range in pseudorapidity, |η| < 5.4, allowing for a reliable systematic study of particle production as a function of energy, centrality and system size.
Comparing Cu+Cu and Au+Au results, we find that the total number of produced charged particles and the overall shape (height
and width) of the pseudorapidity distributions are determined by the number of nucleon participants, N
part. Detailed comparisons reveal that the matching of the shape of the Cu+Cu and Au+Au pseudorapidity distributions over the
full range of η is better for the same N
part/2A value than for the same N
part value, where A denotes the mass number. In other words, it is the geometry of the nuclear overlap zone, rather than just the number of nucleon
participants that drives the detailed shape of the pseudorapidity distribution and its centrality dependence. 相似文献
8.
Adare A Afanasiev S Aidala C Ajitanand NN Akiba Y Al-Bataineh H Alexander J Al-Jamel A Aoki K Aphecetche L Armendariz R Aronson SH Asai J Atomssa ET Averbeck R Awes TC Azmoun B Babintsev V Baksay G Baksay L Baldisseri A Barish KN Barnes PD Bassalleck B Bathe S Batsouli S Baublis V Bauer F Bazilevsky A Belikov S Bennett R Berdnikov Y Bickley AA Bjorndal MT Boissevain JG Borel H Boyle K Brooks ML Brown DS Bucher D Buesching H Bumazhnov V Bunce G Burward-Hoy JM Butsyk S Campbell S Chai JS Chang BS 《Physical review letters》2007,98(16):162301
Differential measurements of elliptic flow (v2) for Au+Au and Cu+Cu collisions at sqrt[sNN]=200 GeV are used to test and validate predictions from perfect fluid hydrodynamics for scaling of v2 with eccentricity, system size, and transverse kinetic energy (KE T). For KE T identical with mT-m up to approximately 1 GeV the scaling is compatible with hydrodynamic expansion of a thermalized fluid. For large values of KE T mesons and baryons scale separately. Quark number scaling reveals a universal scaling of v2 for both mesons and baryons over the full KE T range for Au+Au. For Au+Au and Cu+Cu the scaling is more pronounced in terms of KE T, rather than transverse momentum. 相似文献
9.
Heavy quarkonia production is expected to be sensitive to the formation of a quark gluon plasma (QGP). The PHENIX experiment
has measured J/ψ production at =200 GeV in Au+Au and Cu+Cu collisions, as well as in reference p+p and d+Au runs. J/ψ’s were measured both at mid (|y|<0.35)
and forward (1.2<|y|<2.2) rapidity. In this letter, we present the A+A preliminary results and compare them to normal cold
nuclear matter expectations derived from PHENIX d+Au and p+p measurements as well as to theoretical models including various
effects (color screening, recombination, sequential melting...). 相似文献
10.
Affolder T Akimoto H Akopian A Albrow MG Amaral P Amendolia SR Amidei D Anikeev K Antos J Apollinari G Arisawa T Asakawa T Ashmanskas W Atac M Azfar F Azzi-Bacchetta P Bacchetta N Bailey MW Bailey S de Barbaro P Barbaro-Galtieri A Barnes VE Barnett BA Barone M Bauer G Bedeschi F Belforte S Bellettini G Bellinger J Benjamin D Bensinger J Beretvas A Berge JP Berryhill J Bevensee B Bhatti A Binkley M Bisello D Blair RE Blocker C Bloom K Blumenfeld B Blusk SR Bocci A Bodek A Bokhari W Bolla G 《Physical review letters》2000,85(14):2886-2891
We have measured the polarization of J/psi and psi(2S) mesons produced in pp collisions at sqrt[s] = 1.8 TeV, using data collected at the Collider Detector at Fermilab during 1992-1995. The polarization of promptly produced J/psi [psi(2S)] mesons is isolated from those produced in B-hadron decay, and measured over the kinematic range 4 [5.5]
相似文献
11.
The PHENIX experiment has measured, J/ψ, ψ′ and γ productions for different collision systems in the forward rapidities 1.2 < | η | < 2.2 at ?{SNN }\sqrt {S_{NN} } = 200 GeV. We have observed significant suppressions of J/ψ production in both Cu+Cu and Au+Au collisions relative to the yield in p+p system. The measurements of higher mass heavy
quarkonia states (ψ′ and γ) will help us to constrain various quarkonium suppression models in heavy ion collisions. A first hint of ψ′ and γ productions in 200GeV p+p collisions has been observed at forward and backward rapidities at PHENIX. 相似文献
12.
Agakishiev G Aggarwal MM Ahammed Z Alakhverdyants AV Alekseev I Alford J Anderson BD Anson CD Arkhipkin D Averichev GS Balewski J Barnby LS Beavis DR Behera NK Bellwied R Betancourt MJ Betts RR Bhasin A Bhati AK Bichsel H Bielcik J Bielcikova J Bland LC Bordyuzhin IG Borowski W Bouchet J Braidot E Brandin AV Bridgeman A Brovko SG Bruna E Bueltmann S Bunzarov I Burton TP Cai XZ Caines H Sánchez MC Cebra D Cendejas R Cervantes MC Chaloupka P Chattopadhyay S Chen HF Chen JH Chen JY Chen L Cheng J 《Physical review letters》2012,108(7):072301
We report new STAR measurements of midrapidity yields for the Λ, Λ[over ˉ], K(S)(0), Ξ(-), Ξ[over ˉ](+), Ω(-), Ω[over ˉ](+) particles in Cu+Cu collisions at √S(NN)==200 GeV, and midrapidity yields for the Λ, Λ[over ˉ], K(S)(0) particles in Au+Au at √S(NN)==200 GeV. We show that, at a given number of participating nucleons, the production of strange hadrons is higher in Cu+Cu collisions than in Au+Au collisions at the same center-of-mass energy. We find that aspects of the enhancement factors for all particles can be described by a parametrization based on the fraction of participants that undergo multiple collisions. 相似文献
13.
Back BB Baker MD Ballintijn M Barton DS Betts RR Bickley AA Bindel R Busza W Carroll A Chai Z Decowski MP García E Gburek T George N Gulbrandsen K Halliwell C Hamblen J Hauer M Henderson C Hofman DJ Hollis RS Hołyński R Holzman B Iordanova A Johnson E Kane JL Khan N Kulinich P Kuo CM Lin WT Manly S Mignerey AC Nouicer R Olszewski A Pak R Reed C Roland C Roland G Sagerer J Seals H Sedykh I Smith CE Stankiewicz MA Steinberg P Stephans GS Sukhanov A Tonjes MB Trzupek A Vale C van Nieuwenhuizen GJ 《Physical review letters》2005,94(8):082304
We have measured transverse momentum distributions of charged hadrons produced in Au+Au collisions at sqrt[s(NN)]=62.4 GeV. The spectra are presented for transverse momenta 0.25
相似文献
14.
Adler C Ahammed Z Allgower C Amonett J Anderson BD Anderson M Averichev GS Balewski J Barannikova O Barnby LS Baudot J Bekele S Belaga VV Bellwied R Berger J Bichsel H Billmeier A Bland LC Blyth CO Bonner BE Boucham A Brandin A Bravar A Cadman RV Caines H Calderón de la Barca Sánchez M Cardenas A Carroll J Castillo J Castro M Cebra D Chaloupka P Chattopadhyay S Chen Y Chernenko SP Cherney M Chikanian A Choi B Christie W Coffin JP Cormier TM Cramer JG Crawford HJ Deng WS Derevschikov AA 《Physical review letters》2002,89(20):202301
Inclusive transverse momentum distributions of charged hadrons within 0.2
相似文献
15.
Abelev BI Aggarwal MM Ahammed Z Anderson BD Anderson M Arkhipkin D Averichev GS Bai Y Balewski J Barannikova O Barnby LS Baudot J Bekele S Belaga VV Bellingeri-Laurikainen A Bellwied R Benedosso F Bhardwaj S Bhasin A Bhati AK Bichsel H Bielcik J Bielcikova J Bland LC Blyth SL Bonner BE Botje M Bouchet J Brandin AV Bravar A Burton TP Bystersky M Cadman RV Cai XZ Caines H Calderón de la Barca Sánchez M Castillo J Catu O Cebra D Chajecki Z Chaloupka P Chattopadhyay S Chen HF Chen JH Cheng J 《Physical review letters》2006,97(15):152301
Transverse momentum spectra of pi+/-, p, and p up to 12 GeV/c at midrapidity in centrality selected Au + Au collisions at square root sNN=200 GeV are presented. In central Au + Au collisions, both pi +/- and p(p) show significant suppression with respect to binary scaling at pT approximately >4 GeV/c. Protons and antiprotons are less suppressed than pi+/-, in the range 1.5 approximately < pT approximately < 6 GeV/c. The pi-/pi+ and p/p ratios show at most a weak pT dependence and no significant centrality dependence. The p/pi ratios in central Au + Au collisions approach the values in p + p and d + Au collisions at pT approximately >5 GeV/c. The results at high pT indicate that the partonic sources of pi+/-, p, and p have similar energy loss when traversing the nuclear medium. 相似文献
16.
Abulencia A Adelman J Affolder T Akimoto T Albrow MG Ambrose D Amerio S Amidei D Anastassov A Anikeev K Annovi A Antos J Aoki M Apollinari G Arguin JF Arisawa T Artikov A Ashmanskas W Attal A Azfar F Azzi-Bacchetta P Azzurri P Bacchetta N Badgett W Barbaro-Galtieri A Barnes VE Barnett BA Baroiant S Bartsch V Bauer G Bedeschi F Behari S Belforte S Bellettini G Bellinger J Belloni A Benjamin D Beretvas A Beringer J Berry T Bhatti A Binkley M Bisello D Blair RE Blocker C Blumenfeld B Bocci A 《Physical review letters》2007,98(23):232001
We measure the ratio of cross section times branching fraction, Rp=sigma chi c2 B(chi c2-->J/psi gamma)/sigma chi c1 B(chi c1-->J/psi gamma), in 1.1 fb(-1) of pp collisions at square root s=1.96 TeV. This measurement covers the kinematic range pT(J/psi)>4.0 GeV/c, |eta(J/psi)<1.0, and pT(gamma)>1.0 GeV/c. For events due to prompt processes, we find Rp=0.395+/-0.016(stat)+/-0.015(syst). This result represents a significant improvement in precision over previous measurements of prompt chi c1,2 hadro production. 相似文献
17.
18.
A. Ya. Berdnikov D. A. Ivanishchev D. O. Kotov V. G. Riabov Yu. G. Riabov V. M. Samsonov 《Bulletin of the Russian Academy of Sciences: Physics》2013,77(7):904-907
The production of dielectron pairs is measured in PHENIX experiment during p + p, d + Au, Cu + Cu, and Au + Au collisions at $\sqrt {s_{NN} }$ = 200 GeV. In the mass region between φ and J/ψ mesons, the yield is consistent with expectations from correlated production. In the mass region below φ mesons, the p + p and d+ Au spectra are well described by known contributions from light meson decays. In contrast, the Au + Au minimum bias spectrum in this region is enhanced by a factor of 4.7, concentrated at low p T < 1.5 GeV/s and rapidly rising with centrality. Existing theoretical models cannot describe the observed enhancement. 相似文献
19.
《Physical review letters》2007,98(19):192301
The STAR collaboration at the BNL Relativistic Heavy-Ion Collider (RHIC) reports measurements of the inclusive yield of nonphotonic electrons, which arise dominantly from semileptonic decays of heavy flavor mesons, over a broad range of transverse momenta (1.2
相似文献
20.
We study J/psi production in pp collisions at BNL Relativistic Heavy Ion Collider (RHIC) within the PHENIX detector acceptance range using the color singlet and color octet mechanism which are based on perturbative QCD and nonrelativistic QCD. Here we show that the color octet mechanism reproduces the RHIC data for J/psi production in pp collisions with respect to the p(T) distribution, the rapidity distribution, and the total cross section at square root = 200 GeV. The color singlet mechanism leads to a relatively small contribution to the total cross section when compared to the octet contribution. 相似文献