Threshold effect and \pi^\pm \psi(2S) peak

TL;DR

This paper discusses a resonance-like structure observed in the $\u00b1 \u00b1 (2S)$ mass spectrum from B decays, proposing a mechanism for its production near the $D^* ar{D}_1(2420)$ threshold.

Contribution

It introduces a new interpretation of the observed structure as a threshold effect and suggests experimental tests for this hypothesis.

Findings

Identification of a resonance-like structure at 4433 MeV

Proposed mechanism links the structure to threshold effects

Suggestions for experimental verification

Abstract

A resonance-like structure in the $\pi^\pm \psi(2S)$ mass spectrum arising in $B \to K \pi^\pm \psi(2S)$ has recently been reported. It is noted that the mass of this structure, $4433 \pm 4 \pm 1$ MeV, is not far from the threshold for production of $D^* \bar{D}_1(2420)$. A proposed mechanism for production of this state is suggested, and tests are suggested.