Branching Fraction, Polarization and CP-Violating Asymmetries in B0 -> D*+ D*- Decays

TL;DR

This paper reports measurements of branching fraction, polarization, and CP asymmetries in B0 -> D*+ D*- decays, providing insights into CP violation and testing Standard Model predictions using Belle detector data.

Contribution

First measurement of these parameters in B0 -> D*+ D*- decays with detailed polarization and CP asymmetry analysis.

Findings

Branching fraction B(B0 -> D*+ D*-) = (0.81 +- 0.08(stat) +- 0.11(syst)) x 10^{-3}

Polarization parameters R⊥ and R0 measured as 0.19 +- 0.08 and 0.57 +- 0.08

CP-violating asymmetry parameters S and A measured as -0.75 +- 0.56 and -0.26 +- 0.26

Abstract

We present measurements of the branching fraction, the polarization parameters and CP-violating asymmetries in B0 -> D*+ D*- decays using a 140/fb data sample collected at the Upsilon(4S) resonance with the Belle detector at the KEKB energy-asymmetric e+e- collider. We obtain B(B0 -> D*+ D*-) = [0.81 +- 0.08(stat) +- 0.11(syst)] x 10^{-3}, R\perp = 0.19 +- 0.08(stat) +- 0.01(syst), R0 = 0.57 +- 0.08(stat) +- 0.02(syst), S = -0.75 +- 0.56(stat) +- 0.12(syst) and A = -0.26 +- 0.26(stat) +- 0.06(syst). Consistency with Standard Model expectations is also discussed.