Determination of quantum numbers for several excited charmed mesons observed in $B^- \to D^{*+} \pi^- \pi^-$ decays

TL;DR

This paper performs a detailed amplitude analysis of the decay $B^- o D^{*+} \, \pi^- \, \pi^-$ to determine the quantum numbers and properties of several excited charmed mesons, providing new measurements and insights into their structure.

Contribution

It introduces a quasi-model-independent analysis method to identify and characterize excited charmed mesons in $B$ decays, including quantum number determination and mixing parameter measurement.

Findings

Quantum numbers of several charmed mesons are established.

Resonance parameters for $D_1(2420)$, $D_1(2430)$, $D_0(2550)$, $D^*_1(2600)$, $D_2(2740)$, $D^*_3(2750)$ are measured.

Mixing between $D_1(2420)$ and $D_1(2430)$ is quantified.

Abstract

A four-body amplitude analysis of the $B^- \to D^{*+} \pi^- \pi^-$ decay is performed, where fractions and relative phases of the various resonances contributing to the decay are measured. Several quasi-model-independent analyses are performed aimed at searching for the presence of new states and establishing the quantum numbers of previously observed charmed meson resonances. In particular the resonance parameters and quantum numbers are determined for the $D_1(2420)$, $D_1(2430)$, $D_0(2550)$, $D^*_1(2600)$, $D_2(2740)$ and $D^*_3(2750)$ states. The mixing between the $D_1(2420)$ and $D_1(2430)$ resonances is studied and the mixing parameters are measured. The dataset corresponds to an integrated luminosity of 4.7 $fb^{-1}$, collected in proton-proton collisions at center-of-mass energies of 7, 8 and 13 TeV with the LHCb detector.