Alexis Franck Rothen | Searcharxiv

arXiv2026

Statistical Inference of Scattering Parameters for Exotic Hadronic States in the $J/\psi\,p$ Spectrum

We present a global two-channel Flatt\'e amplitude analysis of the hidden-charm pentaquark candidates observed by the LHCb collaboration in the J/{\psi}p invariant-mass spectrum using the Run 1+2 dataset. We simultaneously fit the three pentaquark amplitudes to the full spectrum, including a polynomial background and complex coupling phases. The scattering length and effective range are extracted from the fitted amplitudes using the effective range expansion, with uncertainties determined through non-parametric bootstrap resampling. While real couplings yield scattering parameters compatible with a molecular interpretation, this conclusion becomes less robust when coupling phases are included. We further find that interference effects are important for the closely spaced Pc(4440)+ and Pc(4457)+ states, demonstrating the limitations of the incoherent-sum approximation.

hep-ph↗

arXiv2026

Systematic study of fully heavy-flavored tetraquarks $Q_1Q_2\bar{Q}_1\bar{Q}_2\,(Q_{1;2} \in \left\{b;c\right\})$: Mass spectra, threshold analysis, and confrontation with LHC data

Experimental searches for fully heavy tetraquark states are actively pursued at the LHC. The LHCb, CMS, and ATLAS collaborations have investigated fully charmed $cc\bar{c}\bar{c}$, mixed $bc\bar{b}\bar{c}$, and fully bottom $bb\bar{b}\bar{b}$ tetraquarks. In particular, narrow structures such as $X(6200)$, $X(6900)$, and $X(7300)$ observed in the di-$J/\psi$ mass spectrum have stimulated considerable theoretical interest. We employ a nonrelativistic diquark-antidiquark model to investigate the mass spectra of ground ($1S$) and excited ($1P$, $2S$, $1D$, $2P$, $3S$, and $4S$) fully heavy tetraquark states. The tetraquarks are modeled as color-singlet bound states of axial-vector diquarks and antidiquarks in the $\mathbf{\bar{3}}$ and $\mathbf{3}$ color representations. The Schr\"odinger equation is solved numerically using a modified Cornell potential and the three-point central difference method, while spin-dependent interactions are treated nonperturbatively. We investigate a broad range of $J^{PC}$ quantum numbers for $S$-, $P$-, and $D$-wave states. The predicted masses are compared with recent LHC observations and other theoretical calculations, and the stability of the states against strong fall-apart decays is examined. Our results support the interpretation of several observed structures as different excitations of fully charmed tetraquarks and provide useful predictions for their experimental identification.

hep-ph↗