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arXiv 0907.4825nucl-ex
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用PHENIX探测器测量碎裂光子

Measurements of Fragmentation Photons with the PHENIX Detector

Ali Hanks

摘要:

与喷流相关的直接光子提供了一个直接测量能量损失对部分子在介质中传播时碎裂的影响。微扰QCD计算描述了直接光子截面以及在次领先的顺序,预测通过部分子碎裂产生的光子的显着贡献。非微扰量,如光子碎裂函数,这是约束不良,导致大的理论不确定性。在p+p碰撞中与喷流相关的光子的测量是这些计算的重要测试,并且是与A+A碰撞进行比较的基本基线测量。选择这样的光子的一个自然方法是研究强子-光子关联。与高pT强子触发器的光子的生产结果,在200 GeV的质心能量的PHENIX p+p数据。

英文摘要:

Direct photons associated with jets provide a direct measurement of the effects of energy loss on the fragmentation of the parton as it propagates through the medium. Perturbative QCD calculations describe the direct photon cross section well at next-to-leading order, predicting a significant contribution from photons produced through parton fragmentation. Non-perturbative quantities such as the photon fragmentation function, which is poorly constrained, lead to large theoretical uncertainties. The measurement of photons correlated with jets in p+p collisions serves as an important test of these calculations and is an essential baseline measurement for comparison to A+A collisions. A natural way of selecting such photons is to study hadron-photon correlations. Results for the production of photons associated with high pT hadron triggers are presented for PHENIX p+p data at 200 GeV center-of-mass energy.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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