Deciphering the production mechanism of the LHCb Pc states
Abstract
The three narrow pentaquarks Pc(4312), Pc(4440), and Pc(4457) observed by LHCb are widely interpreted as hadronic molecules owing to their proximity to the ΣcD̅(*) thresholds. However, heavy-quark spin symmetry predicts additional partner states that have not been seen experimentally, making the production mechanism in Λb0 decays particularly important in understanding their nature. We propose a novel production mechanism, which can naturally explain why only these three LHCb Pc states have been clearly observed. The Pc(4440) and Pc(4457) are produced via the Ds1*(2860)Λc(2595)D̅π box diagram leading to K-ΣcD̅*, followed by rescattering into K- J/ψp. The box diagram develops a box singularity in the vicinity of the Pc(4457), as all four states in the box can go on shell. The Pc states themselves are dynamically generated through the rescattering of the S-wave ΣcD̅(*) to J/ψp. The Pc(4312) proceeds analogously via the Ds0(2590)Λc(2595)D̅*π box diagram but without a box singularity. The near-invisibility of the Σc*D̅(*) molecular states is attributed to the suppressed production of the Λc(2625) in Λb weak decays, as established by the lattice QCD calculations. This mechanism naturally reproduces the data with only two production parameters, whereas previous works required 7 parameters and a finely tuned background, and provides a natural explanation for why the Σc*D̅(*) states are barely visible. It yields unique, falsifiable predictions, Γ(Λb0→ Pc(4440/4457) K→ J/ψp K)/Γ(Λb0→D̅s1*(2860)Λc(2595))≈ (0.2−0.4)%, Γ(Λb0→ Pc(4312) K→ J/ψp K)/Γ(Λb0→ D̅s0(2590)Λc(2595))≈ (0.2−0.8)%.
Related
- NNLL fit of the transverse-momentum-dependent distribution of unpolarised gluons to LHCb data on J/ψ-pair production
- Charm and quarkonium production in collider and fixed-target mode at LHCb
- Hidden charm pentaquarks and the nature of Pc states observed at LHCb
- Partial Entropy production of active particles with hidden states in potentials
- Self-Interacting Sterile Neutrino Cold Dark Matter: Resonant Production Mechanism in the Early Universe
BibTeX
@misc{wang2026deciphering,
title = {{Deciphering the production mechanism of the LHCb $P_c$ states}},
author = {Wen-Jia Wang and Meng-Lin Du and Feng-Kun Guo and Bing Wu},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.24231},
eprint = {2609.24231},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.24231},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Deciphering the production mechanism of the LHCb P_c states
AU - Wen-Jia Wang
AU - Meng-Lin Du
AU - Feng-Kun Guo
AU - Bing Wu
PY - 2026
DA - 2026/09/21
PB - arXiv
DO - 10.48550/arxiv.2609.24231
UR - https://arxiv.org/abs/2609.24231
AB - The three narrow pentaquarks P_c(4312), P_c(4440), and P_c(4457) observed by LHCb are widely interpreted as hadronic molecules owing to their proximity to the Σ_cD̅^(*) thresholds. However, heavy-quark spin symmetry predicts additional partner states that have not been seen experimentally, making the production mechanism in Λ_b^0 decays particularly important in understanding their nature. We propose a novel production mechanism, which can naturally explain why only these three LHCb P_c states have been clearly observed. The P_c(4440) and P_c(4457) are produced via the D_s1^*(2860)Λ_c(2595)D̅π box diagram leading to K^-Σ_cD̅^*, followed by rescattering into K^- J/ψp. The box diagram develops a box singularity in the vicinity of the P_c(4457), as all four states in the box can go on shell. The P_c states themselves are dynamically generated through the rescattering of the S-wave Σ_cD̅^(*) to J/ψp. The P_c(4312) proceeds analogously via the D_s0(2590)Λ_c(2595)D̅^*π box diagram but without a box singularity. The near-invisibility of the Σ_c^*D̅^(*) molecular states is attributed to the suppressed production of the Λ_c(2625) in Λ_b weak decays, as established by the lattice QCD calculations. This mechanism naturally reproduces the data with only two production parameters, whereas previous works required 7 parameters and a finely tuned background, and provides a natural explanation for why the Σ_c^*D̅^(*) states are barely visible. It yields unique, falsifiable predictions, Γ(Λ_b^0→ P_c(4440/4457) K→ J/ψp K)/Γ(Λ_b^0→D̅_s1^*(2860)Λ_c(2595))≈ (0.2−0.4)%, Γ(Λ_b^0→ P_c(4312) K→ J/ψp K)/Γ(Λ_b^0→ D̅_s0(2590)Λ_c(2595))≈ (0.2−0.8)%.
ER -