The New Narrow "D_s" States -- A Minireview

TL;DR

This paper reviews the experimental discovery and properties of two narrow charm-strange meson states, discussing their masses, widths, quantum numbers, and possible interpretations within the quark model.

Contribution

It provides a comprehensive overview of the experimental status and theoretical implications of the newly observed D_s states, highlighting their unexpected masses and potential mixing effects.

Findings

The states have masses of 2317 and 2460 MeV with widths less than 10 MeV.

They are consistent with being 0^+ and 1^+ P-wave charm-strange mesons.

The states may involve mixing between j=1/2 and j=3/2 levels.

Abstract

The experimental status concerning the two new narrow states with charm-strange content is reviewed. The states have masses of 2317 and 2460 MeV, widths less than 10 MeV, isospin consistent with zero, and spin-parities consistent with being 0^+ and 1^+, respectively. Although the masses are lower than the conventional expectation, these states appear to be the j=1/2 P-wave levels of the D_s system, where j is the light quark angular momentum; there may be mixing with the j=3/2 level for the 1^+ state.