Measurement of phi_3 with Dalitz Plot Analysis of B->D(*)K Decay at Belle

TL;DR

This paper measures the unitarity triangle angle phi_3 using Dalitz plot analysis of B->D(*)K decays with Belle data, providing a value with statistical, systematic, and model uncertainties.

Contribution

It introduces a combined Dalitz plot analysis method for B->D(*)K decays to measure phi_3, utilizing a large Belle dataset for improved precision.

Findings

Measured phi_3 as 68 degrees with uncertainties

Two standard deviation interval for phi_3 is 22 to 113 degrees

Demonstrated effectiveness of Dalitz plot analysis in this context

Abstract

We present a measurement of the unitarity triangle angle phi_3 using a Dalitz plot analysis of the three-body decay of the neutral D meson from the B->D(*)K process. Using a 253 fb-1 data sample collected by the Belle experiment, we obtain 276 signal candidates for B->DK and 69 candidates for B->D*K, where the neutral D meson decays into K_Spi+pi-. From a combined maximum likelihood fit to the B->DK and B->D*K modes, we obtain phi_3=68+14-15(stat)+-13(syst)+-11(model). The corresponding two standard deviation interval is 22<phi_3<113.