Quark ACM with topologically generated gluon mass

TL;DR

This paper studies how a small, topologically generated gluon mass affects the anomalous chromomagnetic moments of various quarks, revealing significant dependence for some quarks and negligible for others, with implications for understanding gluon mass effects.

Contribution

It introduces a perturbative calculation of quark ACM considering a topologically generated gluon mass, comparing it with a Proca mass, and analyzes the dependence across different quark flavors and momentum transfers.

Findings

ACM varies significantly with gluon mass for light quarks.

Top and bottom quarks' ACM show negligible gluon mass dependence.

Gluon mass effects are more pronounced at $q^2=-M_Z^2$ than at $q^2=-m_t^2$.

Abstract

We investigate the effect of a small, gauge-invariant mass of the gluon on the anomalous chromomagnetic moment of quarks (ACM) by perturbative calculations at one loop level. The mass of the gluon is taken to have been generated via a topological mass generation mechanism, in which the gluon acquires a mass through its interaction with an antisymmetric tensor field $B_{\mu \nu}$. For a small gluon mass $(<10$ MeV), we calculate the ACM at momentum transfer $q^2=-M_Z^2$. We compare those with the ACM calculated for the gluon mass arising from a Proca mass term. We find that the ACM of up, down, strange and charm quarks vary significantly with the gluon mass, while the ACM of top and bottom quarks show negligible gluon mass dependence. The mechanism of gluon mass generation is most important for the strange quarks ACM, but not so much for the other quarks. We also show the results at $q^2=-m_t^2$. We find that the dependence on gluon mass at $q^2=-m_t^2$ is much less than at $q^2=-M_Z^2$ for all quarks.