Ma Yan-Qing, Qiu Jian-Wei, Sterman George, Zhang Hong
Physics Department, Brookhaven National Laboratory, Upton, New York 11973-5000, USA.
Physics Department, Brookhaven National Laboratory, Upton, New York 11973-5000, USA and C.N. Yang Institute for Theoretical Physics, Stony Brook University, Stony Brook, New York 11794-3840, USA and Department of Physics and Astronomy, Stony Brook University, Stony Brook, New York 11794, USA.
Phys Rev Lett. 2014 Oct 3;113(14):142002. doi: 10.1103/PhysRevLett.113.142002. Epub 2014 Oct 2.
We show that when the factorized cross section for heavy quarkonium production includes next-to-leading power contributions associated with the production of the heavy quark pair at short distances, it naturally reproduces all high p(T) results calculated in nonrelativistic QCD (NRQCD) factorization. This extended formalism requires fragmentation functions for heavy quark pairs, as well as for light partons. When these fragmentation functions are themselves calculated using NRQCD, we find that two of the four leading NRQCD production channels, (3)S(1)([1]) and (1)S(0)([8]), are dominated by the next-to-leading power contributions for a very wide p(T) range. The large next-to-leading order corrections of NRQCD are absorbed into the leading order of the first power correction. The impact of this finding on heavy quarkonium production and its polarization is discussed.
我们表明，当重夸克偶素产生的因子化截面包含与短程重夸克对产生相关的次领头幂次贡献时，它自然地重现了在非相对论性量子色动力学（NRQCD）因子化中计算的所有高横动量（p(T)）结果。这种扩展形式需要重夸克对以及轻部分子的碎裂函数。当使用NRQCD计算这些碎裂函数本身时，我们发现四个主要的NRQCD产生通道中的两个，即(3)S(1)([1])和(1)S(0)([8])，在非常宽的p(T)范围内由次领头幂次贡献主导。NRQCD的大的次领头阶修正被吸收到一阶幂次修正的领头阶中。讨论了这一发现对重夸克偶素产生及其极化的影响。
