Gouranga C. Nayak, Jian-Wei Qiu, George Sterman
Published 2005-12-28Version 1
We discuss factorization in heavy quarkonium production in high energy collisions using NRQCD. Infrared divergences at NNLO are not matched by conventional NRQCD matrix elements. However, we show that gauge invariance and factorization require that conventional NRQCD production matrix elements be modified to include Wilson lines or non-abelian gauge links. With this modification NRQCD factorization for heavy quarkonium production is restored at NNLO.
Comments: 3pages Latex, 3eps figures, Talk given by G. C. Nayak at PANIC05 Santa Fe, NM, USA, October 24-28, 2005
Fragmentation, Factorization and Infrared Poles in Heavy Quarkonium Production
Fragmentation, NRQCD and NNLO Factorization Analysis in Heavy Quarkonium Production
Heavy quarkonium production and polarization
