Heavy quark spin selection rules in meson-antimeson states

TL;DR

This paper explores spin selection rules in heavy quark meson-antimeson states, revealing conditions under which certain decay modes are suppressed, with implications for understanding their decay properties.

Contribution

It introduces new spin selection rules for meson-antimeson molecules in the heavy quark limit, detailing when specific charm-anticharm spin states are forbidden.

Findings

Certain J_{car{c}} states cannot be 0 under specific total spin conditions.

Decays to spin-singlet charmonium are suppressed in these cases.

Constraints on decay properties for selected meson-antimeson systems.

Abstract

In the heavy quark limit, we discuss the spin of the charm-anticharm pair $J_{c\bar{c}}$ in an S-wave meson-antimeson molecule or resonance. One finds two cases that $J_{c\bar{c}}$ cannot be 0: (a) $J=|j_2-j_4|-1$ or $J=j_2+j_4+1$ where $J$ is the total spin of the system and $j_2$ ($j_4$) is the total angular momentum of the light degree of freedom in a charmed meson (antimeson); (b) $J^C=1^+,2^-,3^+,...$, if the two different mesons belong to the same doublet. The decays to spin-singlet charmonium states are suppressed when one of the two conditions is satisfied. We discuss constrained decay properties for selected systems.