# On the quark mass contributions: Analysis Methods for Sigma Terms of the Baryon Octet from Lattice QCD

#### On the quark mass contributions: Analysis Methods for Sigma Terms of the Baryon Octet from Lattice QCD

- Event time: 2:00pm until 3:00pm
- Event date: 16th November 2022
- Speaker: Pia Leonie Jones Petrak (Westfälische Wilhelms-Universität Münster)
- Location: Higgs Centre Seminar Room, Room 4305, James Clerk Maxwell Building (JCMB) James Clerk Maxwell Building Peter Guthrie Tait Road Edinburgh EH9 3FD GB

### Event details

Sigma terms are the quark mass contributions to a given baryon. We study the sigma terms of the full baryon octet (nucleon, lambda, sigma, xi) which has by far not been dealt with as much as the nucleon sigma term on its own. This way we get to investigate flavour symmetry breaking in the octet by determining the not so well-known SU(3) low energy constants (LECs).

The sigma terms are calculated directly from Lattice QCD (on CLS gauge field ensembles employing the Lüscher-Weisz gluon action and the Sheikholeslami-Wohlert fermion action with Nf = 2 + 1) with pion masses ranging from 410 MeV down to the physical value and lattice spacings covering a range between about 0.039 fm and 0.086 fm.

The talk will in particular focus on how the excited states can be controlled as to be able to extract the sigma terms (or rather the ground-state matrix elements needed) reliably. To do so we use different kinds of multi-state fits that is the summation and the ratio method. Also, we look into the effect of priors and including correlations in the fit. Finally, some preliminary results for the SU(3) LECs drawn from a fit to Baryon Chiral Perturbation Theory will be presented.

#### Event resources

### About Particle Physics Theory seminars

The Particle Physics Theory seminar is a weekly series of talks reflecting the diverse interests of the group. Topics include analytic and numerical calculations based on the Standard Model of elementary particle physics, theories exploring new physics, as well as more formal developments in gauge theories and gravity..