Observation of a new excited charm-strange meson $D_{s1}(2933)^+$ in $B^0\to D^+ D^- K^+ \pi^-$ decays

TL;DR

A new charm-strange meson, D_{s1}(2933)^+, was observed with high significance in B^0 decays, with measured mass, width, and quantum numbers, suggesting it as a 2P excited state.

Contribution

First observation of the D_{s1}(2933)^+ meson with detailed measurements, expanding knowledge of charm-strange meson spectroscopy.

Findings

Mass measured at 2933 MeV with uncertainties

Width measured at 72 MeV with uncertainties

Quantum numbers determined as J^P=1^+

Abstract

A new excited charm-strange meson is observed through an amplitude analysis of the full phase space of $B^0\to D^+ D^- K^+ \pi^-$ decays. The analysis is based on a proton-proton collision data sample collected by the \lhcb experiment at a center-of-mass energy $\sqrt{s} = 13\,\text{TeV}$, corresponding to an integrated luminosity of $5.4\text{fb}^{-1}$. The statistical significance of the new state exceeds $10$ standard deviations. Its Breit--Wigner mass and width are measured to be $m_0 = {2933}^{+6}_{-5}(\text{stat})^{+4}_{-3}(\text{syst}) \,\text{MeV} $ and $\Gamma_0 = {72}^{+18}_{-12}(\text{stat})^{+\phantom{0}7}_{-10}(\text{syst}) \,\text{MeV} $, respectively, and its spin-parity quantum numbers are determined to be $J^P = 1^+$. This new meson, denoted as $D_{s1}(2933)^+$, is a candidate for a $D_s(2P^{(\prime)}_{1})^+$ state.