$1/m$ Corrections for Orbitally Excited Heavy Mesons and the $1/2$ - $3/2$ Puzzle

TL;DR

This paper examines how $1/m_c$ corrections influence the spectrum and mixing of orbitally excited $D$-mesons, impacting decay processes and addressing the $1/2$ - $3/2$ puzzle.

Contribution

It introduces a detailed analysis of $1/m_c$ corrections causing mixing between $1^+$ states and explores their effects on decay channels, providing new insights into heavy meson spectroscopy.

Findings

Significant mixing between the two lowest $1^+$ states due to $1/m_c$ corrections.

Altered decay rates for $B o D^{**} \, \ell \bar{\nu}$ processes.

Implications for resolving the $1/2$ - $3/2$ puzzle in heavy meson decays.

Abstract

We re-investigate the effects of the $1/m_c$ corrections on the spectrum of the lowest orbitally excited $D$-meson states. We argue that one should expect the $1/m_c$ corrections to induce a significant mixing between the two lowest lying $1^+$ states. We discuss the implications of this mixing and compute its effect on the semileptonic decays $B \to D^{**} \ell \bar{\nu}$ and the strong $D^{**}$ decays.