18-22 October 2021
Matsue, Shimane Prefecture, Japan
Asia/Tokyo timezone

Small-x Helicity Evolution and the Proton Spin Puzzle

22 Oct 2021, 07:00
Room 501 (Kunibiki Messe)

Room 501

Kunibiki Messe

Parallel Session keynote talk (by invitation only) Nucleon Helicity Structure Nucleon Helicity Structure


Dr Daniel Pitonyak


We report on the first phenomenological analysis of the world polarized deep-inelastic scattering (DIS) data incorporating small-x helicity (Kovchegov-Pitonyak-Sievert) evolution. This framework allows for one to predict the behavior of helicity parton distribution functions (PDFs) down to very low x. Consequently, one can control the uncertainties in these functions beyond the measured region and make precise calculations of the integrals needed to determine the contribution of quark and gluon spin to the proton spin. Therefore, the small-x helicity formalism will play a crucial role in using future Electron-Ion Collider data to resolve the proton spin puzzle.

Primary authors

Dr Daniel Pitonyak Daniel Adamiak (Ohio State University) Yuri Kovchegov (Ohio State University) Wally Melnitchouk (Jefferson Lab) N. Sato (Jefferson Lab) Matt Sievert (New Mexico State)

Presentation Materials