Physics – High Energy Physics – High Energy Physics - Phenomenology
Scientific paper
2005-06-08
Phys.Lett. B625 (2005) 67-75
Physics
High Energy Physics
High Energy Physics - Phenomenology
More explanation about different terms in the velocity expansion
Scientific paper
10.1016/j.physletb.2005.08.057
The approach of nonrelativistic QCD(NRQCD) factorization was proposed to study inclusive production of a quarkonium. It is widely used and successful. However, a recent study of gluon fragmentation into a quarkonium at two-loop level shows that the factorization is broken. It is suggested that the color-octet NRQCD matrix elements should be modified by adding a gauge link to restore the factorization. The modified matrix elements may have extra soft-divergences at one-loop level which the unmodified can not have, and this can lead to a violation of the universality of these matrix elements. In this letter, we examine in detail the NRQCD factorization for inclusive quarkonium production in $e^+ e^-$ annihilation at one-loop level. Our results show that the factorization can be made without the modification of NRQCD matrix elements and it can also be made for relativistic corrections. It turns out that the suggested gauge link will not lead to nonzero contributions to color-octet NRQCD matrix elements at one-loop level and at any order of $v$. Therefore the universality holds at least at one-loop level.
Ma Jian-Ping
Si Zong-Guo
No associations
LandOfFree
NRQCD Factorization and Universality of NRQCD Matrix Elements does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with NRQCD Factorization and Universality of NRQCD Matrix Elements, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and NRQCD Factorization and Universality of NRQCD Matrix Elements will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-538571