发表机构
University of Geneva; Bertoua Higher Teacher’s Training College, University of Bertoua; University of Manchester（日内瓦大学; 贝尔图阿高等师范学院，贝尔图阿大学; 曼彻斯特大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
通过有效力程展开和蒙特卡洛不确定性传播，研究四夸克态χc1(3872)和Tcc+(3875)的近阈值结构，发现大负散射长度和主导分子组分，证明其分子本质。
AI 中文摘要
我们利用有效力程展开（ERE）和共振复合度关系，研究了奇异四夸克候选态$\chi_{c1}(3872)$和$T_{cc}^+(3875)$的近阈值结构。基于实验质量和宽度，我们在双通道框架内提取了散射长度、有效力程和分子复合度系数，并通过$N=50000$个蒙特卡洛样本传播不确定性。我们发现大的负散射长度，$\chi_{c1}(3872)$的$a=-8.49^{+0.93}_{-1.05}$ fm，$T_{cc}^+$的$a=-14.57^{+1.70}_{-1.66}$ fm，以及占主导的分子组分$X_2>0.95$。这些结果对复合度、实验关联和圈函数减除常数的变化具有稳健性。显式的ERE+CDD极点分析发现，与观测极点和自然背景一致的情况下，不存在物理上合理的裸态贡献。我们的结果为这两个态主要具有分子结构提供了强有力的证据，并展示了ERE方法对近阈值奇异强子的稳健性。
英文摘要
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.
Comments29 pages, 7 figures
