[Hadstruct] Minutes of 11th August

[David Richards]

Polarized Gluon distribution

RS gave an update on the status of the analysis of the polarized gluon distribution, using 800 configurations. One important question was the cost/benefit of using more operators vs a smaller number of operators on the full set of configurations, currently 1900; to generate the variational basis with the currently employed set of operators (~8?) would take perhaps one year. So it was a question of balancing statistical precision with the systematics of excited state contributions. A further issue was whether we could get data at flow times less than around 2, and whether that would be sufficient to perform a zero flow time extrapolation.

RS asked whether others could help with the (high-statistics) analysis. CM noted that Trey Anderson had already looked at the earlier gluon data, and would be able to look at this further and describe his analysis in a few weeks. There was also an important need to get the disconnected contributions up and running; these avoided the issues of, e.g. using flow time.

21g

There would be a call for proposals for the new "21g" AMD M100 cluster that was being installed, with new allocations starting on 1st October. ER was somewhat concerned as to whether we would indeed have working code by that time.

Lattice Feedback

WM had been asked about whether you could straightforwardly obtain the pseudo-PDF coordinate-space matching from the momentum-space quasi-PDF approach AR and WM noted that the difference was not merely whether one was simply the FT of the other. There were also questions in the talks about why we needed the normalization of the distributions both for the transversity distributions and for the unpolarized gluon distributions.

Future Workshops/In-Person Meetings.

We discussed the possibility of meeting in person at JLab, perhaps on Wednesdays? In the meantime, both KO and CM would likely have in-person teaching commitments at WM on Tuesday/Thursday so that may offer a more immediate approach for in person meetings.

DR noted that Xiangdong Ji would like another LaMET meeting, probably in November.

Next Meeting

25th Aug, 9am