Mass effect in polarization investigation at BEPC/BES and the B-factory

TL;DR

This paper analyzes how particle masses influence polarization effects in electron-positron annihilation into heavier fermions at BEPC/BES and B-factories, aiding future experimental design.

Contribution

It provides a detailed calculation of polarization effects considering particle masses in specific energy regions, comparing different collider environments.

Findings

Mass effects significantly influence polarization measurements.

Differences observed between BEPC/BES and B-factory environments.

Results assist in optimizing polarization experiments at these facilities.

Abstract

We consider the annihilation process of an electron-positron pair into a pair of heavier fermions when the initial electron and position beams are polarized. By calculating the polarization of the final-state particles, we discuss in detail the effect due to the produced particle masses in the $\tau$-charm energy region at BEPC/BES, and also compare the effect with that at the B-factory. Such a study is useful for the design of possible polarization investigation at the BEPC/BES facility and the B-factory.