[Hadstruct] Minutes of 22nd Jan

[David Richards]

Gluon distribution

TK gave an update on the computation of the gluon momentum fraction in the nucleon. The numerical fitting seemed consistent, however the data did not correspond to the expected phenomenological value, and furthermore showed a one- and two-loop a strong dependence on the flow time in the calculation. TK also showed the expected flow-time dependence using an assumed phenomenological value. Several possible avenues for trying to reconcile this behavior were discussed: were we using the correct matching formula, what was the correct scale for the strong-coupling constant, should the evolution be determined non-perturbatively?

Understanding the pion PDF

Nikhil Karthik (NK) presented a recent analysis trying to understand the Parton distribution function of the pion, using a SU(2) gauge theory in 2+1 dimensions. He described how this approach allowed control over long-distance energy scales to reveal the emergence of NG modes, and how he had developed a framework that might be useful in later studies of hadron structure

Transversity in the nucleon

NK noted that there would be a discussion on the Transversity distributions on Monday, and invited those interested to participate.

Next Meeting

Teaching and other commitments suggested that Wednesdays at 9am would be the most suitable time for future meetings.