$DD^*$ correlation functions in deciphering the nature of $T_{cc}(3875)^+$

TL;DR

This paper investigates the nature of the $T_{cc}(3875)^+$ tetraquark candidate by analyzing $D^*$-$D$ scattering and femtoscopic correlation functions, proposing femtoscopy as a key tool to distinguish between molecular and compact states.

Contribution

It demonstrates that femtoscopic correlation functions can effectively differentiate between molecular and mixed configurations of $T_{cc}(3875)^+$, offering a new method for understanding its structure.

Findings

Femtoscopic correlation functions differ significantly between scenarios.

Correlation functions remain distinguishable for typical LHC sources.

Results provide theoretical guidance for future femtoscopy measurements.

Abstract

Understanding near-threshold strong interactions is essential for disentangling hadronic molecules and compact multiquark states in heavy-flavor spectroscopy. In this context, the doubly charmed tetraquark candidate $T_{cc}(3875)^+$ serves as a critical benchmark because it lies very close to the $D^*$-$D$ thresholds. Motivated by the interaction ambiguity reported recently [\href{https://doi.org/10.1103/kd4s-9rzr}{Phys.Rev.D 113, L031505 (2026)}], we evaluate the $D^*$-$D$ scattering lengths and femtoscopic correlation functions for the molecular and molecule-compact admixture assignments of the $T_{cc}(3875)^+$. We show that, although these scenarios yield similar invariant-mass line shapes, their corresponding femtoscopic correlation functions differ markedly and remain clearly distinguishable for typical particle-emitting sources created at the LHC. Our results indicate that femtoscopy can serve as a sensitive and complementary probe of the near-threshold dynamics of $T_{cc}(3875)^+$, providing vital theoretical references for future LHC femtoscopy measurements.