Near-Threshold Dynamics of \c{hi}c1(3872) and T+cc(3875) States via Effective Range Expansion and Monte Carlo Uncertainty Propagation
Abstract
We investigate the near-threshold structure of the exotic tetraquark candidates χc1(3872) and Tcc+(3875) using the effective-range expansion (ERE) and resonance compositeness relations. From the experimental masses and widths, we extract scattering lengths, effective ranges, and molecular compositeness coefficients within a two-channel framework, with uncertainties propagated through N=50000 Monte Carlo samples. We find large negative scattering lengths, a=−8.49+0.93−1.05 fm for χc1(3872) and a=−14.57+1.70−1.66 fm for Tcc+, and dominant molecular components X2>0.95. The results are robust against variations of compositeness, experimental correlations, and the loop-function subtraction constant. An explicit ERE+CDD-pole analysis finds no physically reasonable bare-state contribution consistent with the observed poles and a natural background. Our results provide strong evidence for predominantly molecular structures of both states and demonstrate the robustness of the ERE approach to near-threshold exotic hadrons.
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BibTeX
@misc{likene2026nearthreshold,
title = {{Near-Threshold Dynamics of \chic1(3872) and T+cc(3875) States via Effective Range Expansion and Monte Carlo Uncertainty Propagation}},
author = {A. A. Atangana Likéné and A. Franck Rothen and J. M. Ema'a Ema'a and P. Pradyun Hebbar and Saralees Nadarajah and Tobias Golling and G. H. Ben-Bolie},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.08289},
eprint = {2609.08289},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.08289},
}
RIS
TY - UNPB
TI - Near-Threshold Dynamics of \c{hi}c1(3872) and T+cc(3875) States via Effective Range Expansion and Monte Carlo Uncertainty Propagation
AU - A. A. Atangana Likéné
AU - A. Franck Rothen
AU - J. M. Ema'a Ema'a
AU - P. Pradyun Hebbar
AU - Saralees Nadarajah
AU - Tobias Golling
AU - G. H. Ben-Bolie
PY - 2026
DA - 2026/09/08
PB - arXiv
DO - 10.48550/arxiv.2609.08289
UR - https://arxiv.org/abs/2609.08289
AB - We investigate the near-threshold structure of the exotic tetraquark candidates χ_c1(3872) and T_cc^+(3875) using the effective-range expansion (ERE) and resonance compositeness relations. From the experimental masses and widths, we extract scattering lengths, effective ranges, and molecular compositeness coefficients within a two-channel framework, with uncertainties propagated through N=50000 Monte Carlo samples. We find large negative scattering lengths, a=−8.49^+0.93_−1.05 fm for χ_c1(3872) and a=−14.57^+1.70_−1.66 fm for T_cc^+, and dominant molecular components X_2>0.95. The results are robust against variations of compositeness, experimental correlations, and the loop-function subtraction constant. An explicit ERE+CDD-pole analysis finds no physically reasonable bare-state contribution consistent with the observed poles and a natural background. Our results provide strong evidence for predominantly molecular structures of both states and demonstrate the robustness of the ERE approach to near-threshold exotic hadrons.
ER -