Electromagnetic polarizabilities of the triplet hadrons in heavy hadron chiral perturbation theory

TL;DR

This study calculates electromagnetic polarizabilities of heavy hadrons using chiral perturbation theory, revealing giant electric polarizabilities in D* mesons due to near-degenerate mass effects and emphasizing pion-loop contributions.

Contribution

It introduces a unified approach for heavy hadron polarizabilities using heavy hadron chiral perturbation theory and heavy diquark-antiquark symmetry, highlighting large electric polarizabilities.

Findings

Giant electric polarizabilities predicted for D* mesons.

Near-degenerate D* and D π masses cause cusp structures in chiral loops.

Polarizabilities vary significantly with heavy-flavor composition.

Abstract

We investigate the electromagnetic polarizabilities of singly heavy mesons and doubly heavy baryons within the framework of heavy hadron chiral perturbation theory up to $\mathcal{O}(p^3)$. We estimate the low-energy constants using the non-relativistic constituent quark model. A striking prediction of our study is the giant electric polarizabilities of the $D^*$ mesons: $\alpha_E(\bar{D}^{*0}) \approx 291.4 \times 10^{-4} \text{fm}^3$ and $\alpha_E(D^{*-}) \approx -0.4-64.4 i \times 10^{-4} \text{fm}^3$. These anomalously large values arise from the near-degenerate mass between $D^*$ and $D \pi$, which are orders of magnitude larger than those of their bottom counterparts. This kinematic coincidence induces a pronounced cusp structure in the chiral loops, reflecting the long-range dynamics of a pion cloud. For doubly heavy baryons, polarizabilities depend strongly on heavy-flavor composition: the $bcq$ system differs markedly from $ccq$ and $bbq$ due to mixing with scalar heavy-diquark states. Using heavy diquark-antiquark symmetry (HDAS), we unify the chiral dynamics of singly heavy mesons and doubly heavy baryons in the heavy-quark limit. The pion-loop contributions dominate the electromagnetic structure of heavy hadrons and provide essential benchmarks for future lattice QCD simulations.