Thermal width and gluo-dissociation of quarkonium in pNRQCD
Thermal width and gluo-dissociation of quarkonium in pNRQCD
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DOI：
10.1007/jhep12(2011)116
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发表时间：
2011-09
影响因子：
5.4
通讯作者：
N. Brambilla;M. A. Escobedo;J. Ghiglieri;A. Vairo
中科院分区：
文献类型：
--
作者：
N. Brambilla;M. A. Escobedo;J. Ghiglieri;A. Vairo
用有效场论方法导出了夸克胶子等离子体中重夸克偶素束缚态的热宽度。有两种现象对宽度有贡献：朗道阻尼现象和热胶子的吸收使色单重态分裂成色八重态重夸克反夸克对。在本文中，我们研究了单线态到八重态的热分裂和所谓的胶子解离之间的关系，胶子解离是一种广泛应用于唯象方法的夸克偶素解离机制。胶子解离热宽度是通过将胶子热分布与胶子和1 S夸克偶素态的横截面卷积到真空中的色八重态夸克-反夸克态来获得的，该横截面处于领先阶，但忽略了色八重态效应，很久以前就由Bhanot和Peskin计算过。首先，我们将证明有效场论框架提供了首阶胶子离解因子分解公式的自然推导，它实际上是单线态到八重态的热碎裂表达式。其次，单重态到八重态的热碎裂表达式将允许我们通过包括八重态势的贡献来改进Bhanot-Peskin截面，这相当于包括重夸克和反夸克之间的终态相互作用。最后，我们将量化由于末态相互作用对胶子解离截面和夸克偶素热宽度的影响。
The thermal width of heavy-quarkonium bound states in a quark-gluon plasma has been recently derived in an effective field theory approach. Two phenomena contribute to the width: the Landau damping phenomenon and the break-up of a colour-singlet bound state into a colour-octet heavy quark-antiquark pair by absorption of a thermal gluon. In the paper, we investigate the relation between the singlet-to-octet thermal break-up and the so-called gluo-dissociation, a mechanism for quarkonium dissociation widely used in phenomenological approaches. The gluo-dissociation thermal width is obtained by convo-luting the gluon thermal distribution with the cross section of a gluon and a 1S quarkonium state to a colour octet quark-antiquark state in vacuum, a cross section that at leading order, but neglecting colour-octet effects, was computed long ago by Bhanot and Peskin. We will, first, show that the effective field theory framework provides a natural deriva-tion of the gluo-dissociation factorization formula at leading order, which is, indeed, the singlet-to-octet thermal break-up expression. Second, the singlet-to-octet thermal break-up expression will allow us to improve the Bhanot-Peskin cross section by including the contribution of the octet potential, which amounts to include final-state interactions between the heavy quark and antiquark. Finally, we will quantify the effects due to final-state interactions on the gluo-dissociation cross section and on the quarkonium thermal width.