"Spectral analysis of gluonic pole matrix elements for fragmentation"

Presented by Asmita Mukherjee, Indian Institute of Technology Bombay

Friday, June 13, 2008, 2:00 pm — Small Seminar Room, Bldg. 510

The non-vanishing of gluonic pole matrix elements can explain the appearance of single spin asymmetries in high-energy scattering processes.
We use a spectator model approach to investigate the spectral properties of quark-quark-gluon correlators and use this to study gluonic pole matrix elements. Such matrix elements appear in principle both for distribution functions (such as Sivers function) and fragmentation functions such as Collins function. We find that for a large class of spectator models, the contribution of gluonic pole matrix element in fragmentation functions vanishes. This outcome is important in the study of universality for fragmentation functions and confirms findings using a different approach.