Precise Measurement of $B^{0}\to \bar{B^{0}$ Mixing Parameters at the $\Upsilon($S)$

TL;DR

This paper reports a precise measurement of B0-B0bar mixing parameters using partial reconstruction techniques on a large dataset from the Cornell Electron Storage Ring, providing updated constraints on mixing probabilities and CP violation parameters.

Contribution

The study introduces a novel partial reconstruction method for B0 decay chains, enabling more accurate measurement of mixing parameters with a large dataset.

Findings

Measured  = 0.198  0.013  0.014

Set upper limit |y_d|<0.41 at 95% CL

Set upper limit |Re(_B)|<0.034 at 95% CL

Abstract

We describe a measurement of B^0-B^0bar mixing parameters exploiting a method of partial reconstruction of the decay chains B0 -> D^{*-}\pi^+ and B0 -> D^{*-}\rho^+. Using 9.6 x 10^6 BBbar pairs collected at the Cornell Electron Storage Ring, we find \chi_d = 0.198 +- 0.013 +- 0.014, |y_d|<0.41 at 95% confidence level, and |Re(\epsilon_B)|<0.034 at 95% confidence level.