Strong decays of $T_{cc}^+$ at NLO in an effective field theory

TL;DR

This paper calculates the next-to-leading-order strong decay width of the $T_{cc}^+$ exotic meson using an effective field theory, improving agreement with experimental data by including pion exchange and rescattering effects.

Contribution

It provides the first NLO calculation of $T_{cc}^+$ decay in an effective field theory framework, incorporating one-pion exchange and rescattering effects.

Findings

NLO corrections improve agreement with LHCb data.

Decay width and invariant mass distribution are accurately modeled.

Uncertainties mainly from scattering length and effective range.

Abstract

The $T_{cc}^+$ exotic meson, discovered by the LHCb Collaboration in 2021, can be interpreted as a molecular state of $D^{(*)0}$ and $D^{(*)+}$ mesons. We compute next-to-leading-order (NLO) contributions to the strong decay of $T_{cc}^+$ in an effective field theory for $D$ mesons and pions, considering contributions from one-pion exchange and final-state rescattering. Corrections to the total width, as well as the differential distribution in the invariant mass of the final-state $D$ meson pair are computed. The results remain in good agreement with LHCb experimental results when the NLO contributions are added. The leading uncertainties in the calculation come from terms which depend on the scattering length and effective range in $D$ meson scattering.