# The 24th International Spin Symposium

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

## The role of the chiral anomaly in polarized deeply inelastic scattering: Topological screening and emergent axion-like dynamics

22 Oct 2021, 08:40
30m
Room 501 (Kunibiki Messe)

### Room 501

#### Kunibiki Messe

Parallel Session Presentation Nucleon Helicity Structure

### Speaker

Dr Andrey Tarasov (The Ohio State University)

### Description

I’ll discuss the role of the chiral anomaly in deep inelastic scattering (DIS) of electrons off polarized protons employing a worldline formalism, which is a powerful framework for the computation of perturbative multi-leg Feynman amplitudes. I’ll demonstrate how the triangle anomaly appears at high energies in the DIS box diagram for the polarized structure function $g_1(x_B,Q^2)$ in both the Bjorken limit of large $Q^2$ and in the Regge limit of small $x_B$. I’ll show that the infrared pole of the anomaly appears in both limits. I will introduce an effective action for spin dependent observables at small x that follows from the cancellation of the infrared pole in the matrix element of the anomaly. This effective action, consistent with anomalous chiral Ward identities, is controlled by two dimensionful scales in Regge asymptotics. The first is the color charge squared per unit area, while the second is the pure Yang-Mills topological susceptibility.

### Primary author

Dr Andrey Tarasov (The Ohio State University)

### Co-author

Raju Venugopalan (Brookhaven National Laboratory)

### Presentation Materials

There are no materials yet.