7–11 Nov 2022
Seville
Europe/Madrid timezone

Hidden-charm $P_{\psi s}^\Lambda$ pentaquarks in a constituent quark model calculation

Not scheduled
20m
Seville

Seville

Universidad Pablo de Olavide, de Sevilla, Ctra. de Utrera, km. 1 41013, Sevilla
Parallel contribution Hadron-hadron interactions

Speaker

Dr Pablo G. Ortega (University of Salamanca)

Description

The discovery of pentaquark states by the LHCb [1] revolutionized Hadron Physics, expanding the usual $qqq$ structure to four quarks and an antiquark. The first observations, detected in the $J/\psi p$ mass spectrum, showed two resonances, dubbed $P_c(4380)^+$ and $P_c(4450)^+$, close to $D^{(*)}N$ thresholds, which suggested a baryon-meson molecular nature in contrast to a compact pentaquark core. The existence of such pentaquarks, with minimum $\bar c cuud$ quark content, anticipated similar hidden-charm structures with strangeness, i.e., with $\bar c c uds$, which were recently confirmed with the discovery of the so-called $P_{cs}(4459)^0$ [2], now called $P_{\psi s}^\Lambda(4459)^0$.

In this work, we provide a theoretical description of the $P_{\psi s}^\Lambda(4459)^0$ and $P_{\psi s}^\Lambda(4338)$ resonances as $\bar D^{(*)}\Xi_c^{(\prime)(*)}$ molecular states in the framework of a constituent quark model that has been extensively used to describe hadron phenomenology [3], in particular exotic states in the baryon spectrum as meson-baryon molecules [4,5]. Such $P_{\psi s}^\Lambda$ states are found in the $J^P=\frac{1}{2}^-$ channel with masses and widths compatible with the experimental measurements in a coupled-channels calculation with all the parameters constrained from previous studies. Other candidates are explored in the $J^P=\frac{3}{2}^-$ and $\frac{5}{2}^-$ channels. Additionally, $P_{\psi ss}^N$ pentaquark states are predicted as $\bar D_s \Xi_c$ molecules.

[1] R. Aaij et al. [LHCb], Phys. Rev. Lett. 115 (2015), 072001.
[2] R. Aaij et al. [LHCb], Sci. Bull. 66 (2021),1278-1287.
[3] J. Vijande, F. Fernandez and A. Valcarce, J. Phys. G 31 (2005), 481.
[4] P. G. Ortega, D. R. Entem and F. Fernandez, Phys. Lett. B 718 (2013),
1381-1384.
[5] P. G. Ortega, D. R. Entem and F. Fernández, Phys. Lett. B 764 (2017),
207-211.

Primary author

Dr Pablo G. Ortega (University of Salamanca)

Co-authors

David Rodriguez Entem (University of Salamanca) Francisco Fernandez (Universidad de Salamanca)

Presentation materials