Testing Anomalous Color-Electric Dipole Moment of the c-Quark from psi'->J/psi+pi(+)+pi(-) at Beijing Spectrometer

TL;DR

This paper establishes the first experimental upper limit on the color-electric dipole moment of the c-quark by analyzing psi' decays at the Beijing Spectrometer, providing insights into CP violation sources.

Contribution

It introduces two effective methods to test the c-quark's CEDM using psi' decay data, setting a new experimental upper bound on its magnitude.

Findings

Upper bound on c-quark CEDM: |d'_c|<3×10^{-14} e cm

First experimental constraint on c-quark CEDM

Proposed methods for testing CEDM in psi' decays

Abstract

If the c-quark has an anomalous color-electric dipole moment (CEDM), it may serve as a new source of CP violation. The strength of such a CP violation depends on the size of the CEDM, d'_c. We propose two effective ways of testing it from the large sample of psi'->J/psi+pi(+)+pi(-) at the Beijing Spectrometer, and the obtained result, |d'_c|<3X10^{-14} e cm (95% C.L.), gives the first experimentally determined upper bound on the CEDM of the c quark.