Measurement of Masses and Widths of Excited Charm Mesons $D_2^*$ and Evidence for Broad States

TL;DR

This paper reports precise measurements of the masses and widths of excited charm mesons D2* and presents evidence for broad states, suggesting the existence of additional L=1, j_q=1/2 charm meson resonances.

Contribution

It provides the first detailed measurements of D2* meson properties and evidence for broad states, indicating potential new excited charm meson resonances.

Findings

Measured D2*0 and D2*+ masses and widths with uncertainties.

Found evidence for broad structures in invariant mass distributions.

Estimated masses and widths of potential j_q=1/2 excited charm mesons.

Abstract

Using data from the FOCUS experiment we analyze the $D^+\pi^-$ and $D^0\pi^+$ invariant mass distributions. We measure the $D_2^{*0}$ mass $M_{D_2^{*0}} = (2464.5 \pm 1.1 \pm 1.9) \mev$ and width $\Gamma_{D_2^{*0}} = (38.7 \pm 5.3 \pm 2.9) \mev$, and the $D_2^{*+}$ mass $ M_{D_2^{*+}} = (2467.6 \pm 1.5 \pm 0.76) \mev$ and width $ \Gamma_{D_2^{*+}} = (34.1 \pm 6.5 \pm 4.2) \mev$. We find evidence for broad structures over background in both the neutral and charged final state. If each is interpreted as evidence for a single L=1, $j_q=1/2$ excited charm meson resonance, the masses and widths are $M_{1/2}^0 =(2407 \pm 21 \pm 35) \mev$, $\Gamma_{1/2}^0 = (240 \pm 55 \pm 59) \mev$, and $M_{1/2}^+ = (2403 \pm 14 \pm 35) \mev$ $\Gamma_{1/2}^+ = (283 \pm 24 \pm 34) \mev$, respectively.