[Hadstruct] Minutes of 6/30 Meeting...

[David Richards]

Dear All

Please find below the minutes of our meeting.  Note the plan is to have the meeting next week at *9am on Friday 10th July*, since the S and T review is earlier in the week.

Regards,
David

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Kaon PDF

CE had been looking at the kaon PDF from the current-current correlator method - in particular the comparison with moment calculations from the Ioffe-time expansion of the correlators, but there appeared to be no extant moment calculations. There was discussion about whether we would expect to see a difference between the pion and kaon - probably not at small Ioffe times, but at larger times. The other possibility would be to look at the QDA would the pion and kaon, which is probably quite a cheap calculation, but should do so in the distillation framework. N.B. Rajan Gupta and company were going to publish a paper shortly on the nucleon PDF moments using the 2+1 clover lattices, following their recent paper on the 2+1+1 HISQ lattices.

Transversity/helicty

The correlators had been generated on Frontera but needed to be analyzed. We need to adopt a strategy to analyze them, and in particular check on the formalism (described in Musch et al?). One should check would be the transverse displacement and see whether the signal-to-noise is indeed better by dividing by a denominator at same momentum.

CLS analysis

JK described the fits to the CLS analysis at multiple lattice spacings. In particular, he examined the dependence on the "smooth" parametrization. One question was the stability under the number of parameters in the Taylor expansion. One question is how do we decide where to "truncate" the series - should we, for example, require that coefficients be reducing with power. One question was the appropriate of an expansion in Ioffe time.

Gluon Distribution

RS reported on testing on whether the relationship between the polarized ME held.

Running

Gluon PDF: eigenvectors etc are better done on Haswell/SKX nodes. Currently running at NERSC.

Generalized Perambulators and nucleon contractions: running at Frontera.

Agenda

Discussion of parameterization and evolution of PDFs (KO, JWQ).

Next Meeting.

FRIDAY 10th July at 9am

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