Speaker:  Prof. Anuradha Misra, DAE Raja Ramanna Fellow (University of Mumbai, India)

Host:  Prof. James Vary

Title:

Spin Structure of Proton

Abstract:

Discovery of point-like scatterers inside the proton in the famous Deeply Inelastic Scattering experiments at SLAC in early 1970’s confirmed the Quark hypothesis of Gell Mann and Zweig and validated Feynman’s Parton Model. An essential ingredient of the Parton Model (and its improved version based on Quantum Chromodynamics) are Parton Distribution Functions (PDFs), which describe the distribution of partons inside the nucleon and which are important inputs in the calculations of scattering cross sections being measured at the high energy colliders.
A major challenge towards a better understanding of proton’s internal structure is to understand spin structure of proton which is probed through polarized beam experiments. These studies require introduction of spin and transverse momentum dependent parton distribution functions (TMDPDFs) in the theoretical formalism. One such function is Sivers Function which quantifies the correlation of quark transverse momentum and proton’s transverse spin.
Beginning with a historical introduction to the Quark-Parton Model, the talk will discuss the spin structure of proton with focus on the Gluon Sivers Function and its effect in polarized scattering.