Measurement of the Mass Difference m(B0) - m(B+)

TL;DR

This paper reports a precise measurement of the mass difference between B0 and B+ mesons using a large dataset from the BABAR experiment, providing important insights into heavy meson properties.

Contribution

The study presents the first high-precision measurement of the B0 - B+ mass difference using a large sample of B meson decays at BABAR.

Findings

Mass difference measured as +0.33 MeV/c^2

Statistical and systematic uncertainties quantified

Results consistent with theoretical predictions

Abstract

Using 230 million B Bbar events recorded with the BABAR detector at the e+ e- storage rings PEP-II, we reconstruct approximately 4100 B0 to J/psi K+ pi- and 9930 B+ to J/psi K+ decays with J/psi to mu+ mu- and e+ e-. From the measured B-momentum distributions in the e+ e- rest frame, we determine the mass difference m(B0) - m(B+) = (+0.33 +- 0.05 +- 0.03) MeV/c^2.