Amplitude analysis of $B^0 \rightarrow \bar{D}^0 K^+ \pi^-$ decays

TL;DR

This paper performs an amplitude analysis of B0 decays to Dbar0 K+ pi- using LHCb data, identifying resonant contributions and measuring resonance parameters to aid future CKM angle gamma measurements.

Contribution

It introduces a detailed amplitude model for B0 to Dbar0 K+ pi- decays, including multiple resonances and broad structures, with measured resonance parameters.

Findings

Measured masses and widths of D*_0(2400)^- and D*_2(2460)^-

Determined complex amplitudes and fit fractions for decay components

Developed an amplitude model for future CKM angle gamma analysis

Abstract

The Dalitz plot distribution of $B^0 \rightarrow \bar{D}^0 K^+ \pi^-$ decays is studied using a data sample corresponding to $3.0\rm{fb}^{-1}$ of $pp$ collision data recorded by the LHCb experiment during 2011 and 2012. The data are described by an amplitude model that contains contributions from intermediate $K^*(892)^0$, $K^*(1410)^0$, $K^*_2(1430)^0$ and $D^*_2(2460)^-$ resonances. The model also contains components to describe broad structures, including the $K^*_0(1430)^0$ and $D^*_0(2400)^-$ resonances, in the $K\pi$ S-wave and the $D\pi$ S- and P-waves. The masses and widths of the $D^*_0(2400)^-$ and $D^*_2(2460)^-$ resonances are measured, as are the complex amplitudes and fit fractions for all components included in the amplitude model. The model obtained will be an integral part of a future determination of the angle $\gamma$ of the CKM quark mixing matrix using $B^0 \rightarrow D K^+ \pi^-$ decays.