Lifetime Differences, direct CP Violation and Partial Widths in D0 Meson Decays to K+K- and pi+pi-

TL;DR

This paper reports measurements of decay rates and CP violation in D0 meson decays to K+K- and pi+pi-, finding no evidence for CP violation or mixing, and providing a ratio of partial widths.

Contribution

The study provides precise measurements of decay width ratios and CP asymmetries in D0 decays, with no observed CP violation or mixing, improving understanding of charm meson behavior.

Findings

Partial width ratio Gamma(D0->K+K-)/Gamma(D0->pi+pi-) = 2.96±0.16±0.15

No evidence for direct CP violation in K+K- and pi+pi- decays

Measured lifetime difference y_CP = -0.012±0.025±0.014, indicating no mixing

Abstract

We describe several measurements using the decays D0->K+K- and pi+pi-. We find the ratio of partial widths, Gamma(D0->K+K-)/Gamma(D0->pi+pi-), to be 2.96+/-0.16+/-0.15, where the first error is statistical and the second is systematic. We observe no evidence for direct CP violation, obtaining A_CP(KK) = (0.0+/-2.2+/-0.8)% and A_CP(pipi = (1.9+/-3.2+/-0.8)%. In the limit of no CP violation we measure the mixing parameter y_CP = -0.012+/-0.025+/-0.014 by measuring the lifetime difference between D0->K+ K- or pi+pi- and the CP neutral state, D0->K-pi+. We see no evidence for mixing.