Phenomenology of Pc(4380)+, Pc(4450)+ and related states

Abstract

Abstract. The P c(4380)+ and Pc(4450) + states recently discovered at LHCb have masses close to several relevant thresholds, which suggests they can be described in terms of meson-baryon degrees of freedom. This article explores the phenomenology of these states, and their possible partners, from this point of view. Competing models can be distinguished by the masses of the neutral partners which have yet to be observed, and the existence or otherwise of further partners with different isospin, spin, and parity. Future experimental studies in different decay channels can also discriminate among models, using selection rules and algebraic relations among decays. Among the several possible meson-baryon pairs which could be important, one implies that the states are mixtures of isospins 1/2 and 3/2, with characteristic signatures in production and decay. A previous experimental study of a Cabibbo-suppressed decay showed no evidence for the states, and further analysis is required to establish the significance of this non-observation. Several intriguing similarities suggest that P c (4450) + is related to the X(3872) meson.

J/ψNinteractions revisited andΛb0→Xiao1 2017Phys. Rev. D15090View full textAdd to dashboardCite

“…From the similar results with the Λ 0 b → J=ψK − p and the Λ 0 b → J=ψπ − p decays, seen in the upper panels of Fig. 5, indeed, the two P c states should also be seen in Λ 0 b → J=ψπ − p decays as suggested in the early research [37,38] and found in Ref. [39].…”

“…As suggested in Refs. [37,38], LHCb found a new evidence of the observation of these two states by a full amplitude analysis of the Λ 0 b → J=ψpπ − decays [39]. It was remarked before in Ref.…”

The hidden-charm pentaquark and tetraquark states

“…[404] In Ref. [407], Burns studied the model-independent phenomenology of the P c (4380) and P c (4450) pentaquark states based on the meson-baryon molecular configuration. He analyzed possible spin-parity assignments for these two states and speculated various decay patterns and production processes.…”

LHCb results on exotics and pentaquark states

“…Observations of the same two pentaquark states in another decay would strengthen their interpretation as genuine exotic baryonic states, rather than kinematical effects related to the so called triangle singularity [5,6]. The LHCb collaboration has performed an amplitude analysis of Λ b → J/ψpπ − decays, which are related to Λ b → J/ψpK − decays via Cabibbo suppression [7].…”