[Theory-seminars] Cake seminar tomorrow (new Zoom link!) - Caroline Costa

[Patrick Barry]

Hello All,

Tomorrow, December 6th at 1:00PM we will have our next (virtual) cake seminar, given by our very own Caroline Costa. In anticipation for our collective switch to ZoomGov in the coming calendar year, we believe this would serve as an excellent opportunity to try out a zoom connection for seminars. So rather than our usual Bluejeans link, Caroline's seminar will be given on the following ZoomGov  link: https://jlab-org.zoomgov.com/j/1602131840?pwd=SVJEVHFWaW5NYzlNOUhaVExmT3JMZz09

Please see below for the details of Caroline's talk.

Cake Seminar
Monday, December 6th, 1:00PM
Caroline Costa (JLab) will speak about "Quark and Gluon Distributions within Constituent Quarks and the Pion"

Abstract:
Parton distribution functions (PDFs) encode relevant information on the 1D structure of hadrons. An approach to compute these functions are through model calculations. In PDF calculations, the effort has so far been on obtaining quark distributions, while gluon distributions remain largely unexplored. Traditionally, the gluon distribution is either inferred indirectly or is assumed to be generated entirely perturbatively by DGLAP evolution equations. However, since several of the major open questions in hadron physics — such as the origin of hadron mass, and the distribution of mass, momentum and spin in the proton — are believed to involve gluonic contributions at all renormalization scales, it is crucial to have gluonic observables directly calculated in effective models of QCD. In this talk I will present a model framework that allows a direct calculation of the gluon PDF of constituent quarks and the pion. The quark target model (QTM) consists of embedding a constituent quark with a quark and gluonic substructure. The quark and gluon distributions in the QTM are explicitly calculated to leading order in the quark-gluon coupling strength. The gauge invariance of the results is demonstrated by comparing both covariant and light cone gauges, with the former including an explicit Wilson line contribution that must be present in covariant PDF calculation. We also consider the impact of a gluon mass using the gauge invariant formalism proposed by Cornwall, and combine these QTM results with two quark-level models to obtain quark and gluon PDFs for the pion.


See you tomorrow!
Astrid, Colin, and Patrick

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