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1.
The medium modifications of J/ψ production in d-Au collisions at √SNN= 200 GeV are studied in the Glauber model. By means of the c.m. energy loss parameter per collision studied in Drell-Yan process,taking account of the inhomogeneous shadowing effect, we find that the initial-state energy loss effect can be ignored in d-Au collisions at mid-rapidity. Then, the final-state J/ψ absorption effect is also considered and the theoretical results are in good agreement with the recent experimental data given by PHENIX. Finally,the experimental results of J/ψ production in d-Pb collisions are also predicted at RHIC and LHC energies respectively. 相似文献
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At high energies, Drell-Yan process can be viewed in the target rest frame as bremsstrahlung of massive photons, rather than parton annihilation. In this paper, the ratio of the p-A Drell-Yan cross section per nucleon for an 800 GeV proton beam incident on Fe, W, and Be targets are calculated by means of the color dipole approach in the target rest system. It is shown that our calculations can quite well fit the Fermilab E866 experimental data with considering the nuclear shadowing effect in p-A Drell-Yan process and without the energy loss effect in it. 相似文献
3.
The energy loss effect in nuclear matter is another nuclear effect apart from the nuclear effects on the parton distribution as in deep inelastic scattering process. The quark energy loss can be measured best by the nuclear dependence of the high energy nuclear Drell-Yan process. By means of three kinds of quark energy loss parameterizations given in literature and the nuclear parton distribution extracted only with lepton-nucleus deep inelastic scattering experimental data, measured Drell-Yan production cross sections are analyzed for 800 GeV proton incident on a variety of nuclear targets from FNAL E866. It is shown that our results with considering the energy loss effect are much different from those of the FNAL E866, who analyzes the experimental data with the nuclear parton distribution functions obtained by using the deep inelastic IA collisions and pA nuclear Drell-Yan data. Considering the existence of energy loss effect in Drell-Yan lepton pairs production, we suggest that the extraction of nuclear parton distribution functions should not include Drell-Yan experimental data. 相似文献
4.
C.-G. Duan L.-H. Song L.-J. Huo G.-L. Li 《The European Physical Journal C - Particles and Fields》2003,29(4):557-561
The energy loss effect in nuclear matter, which is a nuclear effect apart from the nuclear effect on the parton distribution as in deep-inelastic scattering process, can be measured best by the nuclear dependence of the high energy nuclear Drell-Yan process. By means of the nuclear parton distribution studied only with lepton deep-inelastic scattering experimental data, the measured Drell-Yan production cross sections for 800 GeV proton incident on a variety of nuclear targets are analyzed within the Glauber framework which takes into account the energy loss of the beam proton. It is shown that the theoretical results with considering the energy loss effect are in good agreement with the FNAL E866 data.Arrival of the final proofs: 24 June 2003 相似文献
5.
DUANChun-Gui CUIShu-Wen YANZhan-Yuan 《理论物理通讯》2005,44(1):123-127
The energy loss effect in nuclear matter is another nuclear effect apart from the nuclear effects on the parton distribution as in deep inelastic scattering process. The quark energy loss can be measured best by the nuclear dependence of the high energy nuclear Dre11-Yan process. By means of three kinds of quark energy loss parameterizations given in literature and the nuclear parton distribution extracted only with lepton-nucleus deep inelastic scattering experimental data, measured Dre11-Yan production cross sections are analyzed for 800 GeV proton incident on a variety of nuclear targets from FNAL E866. It is shown that our results with considering the energy loss effect are much different from those of the FNAL E866, who analyzes the experimental data with the nuclear parton distribution functions obtained by using the deep inelastic IA collisions and pA nuclear Drell-Yan data. Considering the existence of energy loss effect in Drell-Yan lepton pairs production, we suggest that the extraction of nuclear parton distribution functions shoul““““d not include Dre11-Yan experimental data. 相似文献
6.
利用Glauber模型以及DGLAP方程下的核内核子的部分子分布函数, 在次领头阶QCD下计算了Drell-Yan过程中的能量损失效应, 计算表明QCD修正并不能改善理论结果与试验结果的符合, 尤其是p-W与p-Be以x1为变量的微分截面比. 原因是所用的核内核子部分子的分布函数是以领头阶近似为基础并通过演化方程得到的. 于是利用在次领头阶微扰QCD下得到的核遮蔽效应核内核子的部分子分布函数重新计算了次领头阶QCD修正对Drell-Yan过程能量损失的贡献. 计算结果表明康普顿散射过程与湮没过程中应该有更多的能量损失. 相似文献
7.
We calculate the differential Drell-Yan production cross section in proton-nucleus collisions by including both next-to-leading order perturbative effects and effects of the nuclear medium. We demonstrate that dilepton production in fixed target experiments is an excellent tool to study initial-state parton energy loss in large nuclei and to accurately determine the stopping power of cold nuclear matter. We provide theoretical predictions for the attenuation of the Drell-Yan cross section at large values of Feynman xF and show that for low proton beam energies experimental measurements at Fermilab?s E906 can clearly distinguish between nuclear shadowing and energy loss effects. If confirmed by data, our results may help determine the quark radiation length in cold nuclear matter X0∼10−13 m. 相似文献
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By means of two typical kinds of quark energy loss parametrization and the nuclear parton distribu-tions determined only with lepton-nuclear deep inelastic scattering experimental data, a leading order analysis is performed on the proton-induced Drell-Yau differential cross section ratios of tungsten versus deuterium as a function of the quark momentum fraction in the beam proton and target nuclei. It is found that the theoretical results with quark energy loss are in good agreement with the experimental data. The quark energy loss effect produces approximately 3% to 11% suppression on the Drell-Yan differential cross section ratios RW/D in the range 0.05 ≤ x2≤ 0.3. The application of nuclear Drell-Yan data with heavy targets is remarkably subject to difficulty in the constraint of the nuclear sea quark distribution. 相似文献
10.
考虑非微扰量子色动力学物理真空夸克凝聚效应,计算了碳核与碳核在质心系能量分别为630和200GeV时碰撞Drell—Yan过程的K因子,以及加入核遮蔽因子后非微扰效应对K因子的影响,并把计算结果与没有考虑夸克凝聚非微扰效应的K值进行了对比。结果表明,非微扰效应和核遮蔽效应对K因子影响很小。Considering quark condensate contributions from the QCD vacuum, the non-perturbative effect on the K-factor is investigated for the C-C collision Drell-Yan process with and without nuclear shadowing respectively, at the center-of-mass energy √s= 630 and 200 GeV. Comparison of the results indicates that both the non-perturbative effect and the nuclear shadowing effect pose a weak influence on the K-factor. 相似文献
11.
Johnson MB Kopeliovich BZ Potashnikova IK McGaughey PL Moss JM Peng JC Garvey GT Leitch MJ Adams MR Alde DM Baer HW Barlett ML Brown CN Cooper WE Carey TA Danner G Hoffmann GW Hsiung YB Kaplan DM Klein A Lee C Lillberg JW McCarthy RL Mishra CS Wang MJ;FNAL E Collaboration 《Physical review letters》2001,86(20):4483-4487
We report an analysis of the nuclear dependence of the yield of Drell-Yan dimuons from the 800 GeV/c proton bombardment of 2H, C, Ca, Fe, and W targets. Employing a new formulation of the Drell-Yan process in the rest frame of the nucleus, this analysis examines the effect of initial-state energy loss and shadowing on the nuclear-dependence ratios versus the incident proton's momentum fraction and dimuon effective mass. The resulting energy loss per unit path length is -dE/dz = 2.32+/-0.52+/-0.5 GeV/fm. This is the first observation of a nonzero energy loss of partons traveling in a nuclear environment. 相似文献
12.
By means of two typical kinds of quark energy loss parametrization and the nuclear parton distributions determined only with lepton-nuclear deep inelastic scattering experimental data, a leading order analysis is performed on the proton-induced Drell-Yan differential cross section ratios of tungsten versus deuterium as a function of the quark momentum fraction in the beam proton and target nuclei. It is found that the theoretical results with quark energy loss are in good agreement with the experimental data. The quark energy loss effect produces approximately 3% to 11% suppression on the Drell-Yan differential cross section ratios RW/D in the range 0.05≤x2≤0.3. The application of nuclear Drell-Yan data with heavy targets is remarkably subject to difficulty in the constraint of the nuclear sea quark distribution. 相似文献
13.
Two important initial-state nuclear effects in hadron-nucleus collisions are considered. The ratios of inclusive differential
cross-sections for Drell-Yan dimuon production are calculated. The calculated results are compared to the E866 data. It is
shown that the consideration of multiple soft rescatterings of incident quarks in nuclei and initial-state quark energy loss
effects allow to get a good agreement between the calculated results and the experimental data. 相似文献
14.
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
15.
The energy-loss effect in nuclear matter is another nuclear effect apart from the nuclear effects on the parton distribution as in deep inelastic scattering process. The quark energy loss can be measured best by the nuclear dependence of the high energy nuclear Drell-Yan process. By means of two typical kinds of quark energy-loss parametrization and the different sets of nuclear parton distribution functions, we present an analysis of the E866 experiments on the nuclear dependence of Drell-Yan lepton pair production resulting from the bombardment of Be, Fe and W targets by 800 GeV protons at Fermilab. It is found that the quark energy loss in cold nuclei is strongly dependent on the used nuclear parton distribution functions. The further prospects of using relatively low energy protons incident on nuclear targets are presented by combining the quark energy-loss rate determined from a fit to the E866 nuclear-dependent ratios versus x
1, with the nuclear parton distribution functions given from lA deep inelastic scattering (DIS) data. The experimental study of the relatively low energy nuclear Drell-Yan process can give valuable insight in the energy loss of the fast quark propagating through cold nuclei and help to pin down nuclear parton distribution functions.Received: 8 September 2004, Revised: 18 October 2004, Published online: 11 January 2005PACS:
24.85. + p, 13.85.Qk, 25.40.-h, 25.75.Nq 相似文献
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The suggestion that nuclear shadowing in deep inelastic scattering is primarily a parton phenomenon is extended to the Drell-Yan reaction on heavy nuclei. The nuclear structure functions required to describe the latter process are found to be compatible with those obtained from an analysis of the shadowing data, and lend weight to the hypothesis that this is indeed a parton phenomenon. 相似文献
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19.
P. E. Reimer 《The European Physical Journal A - Hadrons and Nuclei》2007,31(4):593-596
The large ˉ(x)/ˉ(x) ratio observed by Fermilab E866/NuSea convincingly demonstrated that the sea is not simply a result of pQCD. Moreover, meson
cloud models also failed to explain fully the observed kinematic dependence. The Drell-Yan mechanism offers a unique, selective
probe of antiquarks in the nucleon. Fermilab has approved a new Drell-Yan experiment, E906, that will exploit this feature
to probe ˉ(x)/ˉ(x) by measuring the ratio of cross-sections for the proton-induced Drell-Yan process on hydrogen to deuterium. When the nucleon
is contained in a nucleus, the nucleon's parton distributions should to be modified; although this effect was not seen in
the sea quark distributions obtained by Fermilab E772 with Drell-Yan scattering. The upcoming E906 Drell-Yan experiment will
provide much more precise measurements over a wider kinematic range in order to guide and challenge the theoretical models. 相似文献
20.
We present a phenomenological study of the XF dependence of quarkonium production in high-energy proton-nucleus collisions. The χF dependence of comover contributions is introduced to account for the observed quarkonium suppression at low χF. Combining comover contributions, nuclear shadowing effect, energy loss mechanism and nuclear absorption together we reproduce the overall χF dependence of E772/E789 data. 相似文献