Some decay properties of hidden-charm pentaquarks as baryon-meson molecules

Abstract

It is pointed out that the previously suggested interpretation of the hidden-charm pentaquarks P c (4312), P c (4440) and P c (4457) as molecular bound states of Σ cD and Σ cD * baryon-meson pairs gives rise to specific relations for their decays. In particular, the heavy quark spin symmetry predicts ratios of rates of decays of each of the molecules to J/ψp and to η c p as well as of the decays to Λ cD and to Λ cD * . Experimental studies of these relations would thus provide an indicative probe of the molecular structure.The initial experimental evidence [1, 2] for hidden-charm pentaquarks has been recently refined into an observation [3] of three relatively narrow resonances P c (4312), P c (4440) and P c (4457) in the J/ψp system produced in the decays Λ b → J/ψpK. The measured positions of the resonance peaks are just few MeV below the thresholds for hidden-charm baryon-meson channels Σ cD and Σ cD * , and the experimental report [3] strongly suggests an interpretation of the lowest P c (4312) resonance as a shallow bound S wave state of Σ cD with the spinparity J P = 1/2 − and the two higher peaks as similar S wave bound systems of Σ cD * with J P = 1/2 − and J P = 3/2 − . Existence of molecular states with hidden heavy flavor was suggested long ago [4], and similar heavy meson-antimeson systems have been observed both with hidden charm [e.g. X(3872) [5]] and the bottomonium-like Z b (10610) and Z b (10650) [6].(Recent reviews of multiquark hadrons including molecular systems with hidden heavy flavor

Decays of Pc into J/ψN and ηcN with he

“…where the η c N couples only to the states with J = 1/2 in an S-wave. The ratioshD Σc(1/2) /hD Σc(1/2) = − √ 3 andhD * Σc(1/2) /hD * Σc(1/2) = − √ 3/5 agree with those derivedin Ref [65]…”

Molecular interpretation of the Pc(4440) and Pc(4457) sta

“…When sufficient phase space is available, molecular states can decay by the strong decay of their constituents [4,73,74]. An electroweak version of this mechanism would occur via neutron decay if the deuteron binding energy were less than the neutron-proton mass difference.…”

Selected strong decays of pentaquark State $$P_c(4312)$$ in a chiral constituent quark model

“…We first calculate the spin-flavor-color coefficients by using the spin-isospin wave functions in both initial and final states shown in eqs. (7), (15) and (21) and re-coupling coefficients. The obtained spin-flavor-color (SFC) coefficients are tabulated in Table II.…”