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arXiv 0812.2536hep-ph
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强非阿贝尔场中奇异和魅夸克对的产生

Strange and charm quark-pair production in strong non-Abelian field

Peter Levai, Vladimir Skokov

摘要:

我们研究了重离子碰撞早期的奇异夸克对和粲夸克对的产生。我们的动力学模型是基于维格纳函数方法的费米子对生产在强非阿贝尔领域。为了描述两个碰撞重离子的重叠,我们采用了脉冲状的含时色场。计算是在有限流夸克质量的SU(2)色模型中进行的。对于奇异夸克对的产生,得到的结果与我们预期的一样接近于Schwinger极限。对于粲夸克,决定夸克对产生效率的是场脉冲的大的时间宽度倒数,而不是大的粲夸克质量。因此,我们没有观察到与通常的Schwinger形式主义有关的粲夸克对产生的预期抑制,但我们的计算结果是相对较大的粲夸克产额。这种效应也出现在阿贝尔模型中,表明快变非阿贝尔胶子场的粒子对产生强烈偏离粲夸克的Schwinger极限。给出了光夸克对、奇异夸克对、粲夸克对的数密度以及不同的抑制因子随色电场作用特征时间的变化。

英文摘要:

We have investigated strange and charm quark-pair production in the early stage of heavy ion collisions. Our kinetic model is based on a Wigner function method for fermion-pair production in strong non-Abelian fields. To describe the overlap of two colliding heavy ions we have applied the time-dependent color field with a pulse-like shape. The calculations have been performed in an SU(2)-color model with finite current quark masses. For strange quark-pair production the obtained results are close to the Schwinger limit, as we expected. For charm quark the large inverse temporal width of the field pulse, instead of the large charm quark mass, determines the efficiency of the quark-pair production. Thus we do not observe the expected suppression of charm quark-pair production connecting to the usual Schwinger-formalism, but our calculation results in a relatively large charm quark yield. This effect appears in Abelian models as well, demonstrating that particle-pair production for fast varying non-Abelian gluon field strongly deviates from the Schwinger limit for charm quark. We display our results on number densities for light, strange, charm quark-pairs, and different suppression factors as the function of characteristic time of acting chromo-electric field.

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