Pc(4457)+ , Pc

Abstract

In a chromomagnetic model, we analyze the properties of the newly observed P c ð4457Þ þ , P c ð4440Þ þ , and P c ð4312Þ þ states. We estimate the masses of the ðuudÞ 8 c ðccÞ 8 c and ðudsÞ 8 c ðccÞ 8 c pentaquark states by considering the isospin breaking effects. Their values are determined by calculating mass distances from the Σ þþ c D − and Ξ 0þ c D − thresholds, respectively. It is found that the isospin breaking effects on the spectrum are small. From the uncertainty consideration and the rearrangement decay properties in a simple model, we find that it is possible to assign the P c ð4457Þ þ , P c ð4440Þ þ , and P c ð4312Þ þ as J P ¼ 3=2 − , 1=2 − , and 3=2 − pentaquark states, respectively. The assignment in the molecule picture can be different, in particular for the P c ð4312Þ þ . The information from open-charm channels, e.g., B½P c → Σ þþ c D − =B½P c → J=ψp, will play an important role in distinguishing the inner structures of the P c states. Discussions and predictions based on the calculations are also given.

One pion exchange and the quantum numbers of the Pc(4440) and PValderrama1 2019Phys. Rev. D772390View full textAdd to dashboardCite

“…− molecular pentaquark is expected to be more bound than its J P ¼ 1 2 − partner. In contrast in the traditional one boson exchange model this pattern is apparently inverted [2,11], with the lower spin molecules being more bound than the higher spin ones. However a recent work [45], which has revisited the application of the one boson exchange model to heavy antimeson-baryon molecules, suggests that this is not necessarily the case and that scenario B might be the most probable.…”

“…The P c ð4312Þ, P c ð4440Þ and P c ð4457Þ are three hiddencharm pentaquark-like states recently discovered by the LHCb collaboration [1]. Owing to their closeness to thē DΣ c andD Ã Σ c thresholds, they have been theorized to be S-wave meson-baryon bound states [2][3][4][5][6][7][8] (other explanations include hadrocharmonium [9] or a compact pentaquark [10,11]). The most natural identification is that the P c ð4312Þ is aDΣ c molecule and the P c ð4440Þ and P c ð4457Þ areD Ã Σ c molecules.…”

Production of Pc states from Λb decay

“…With these upper limits, one can obtain the lower limits of the branching ratio Λ b → P c K, which are ð2.08 þ2. 43 −0.61 Þ × 10 −5 , ð1.54 þ0. 62 −0.52 Þ × 10 −4 , and ð4.47 þ2.03 −1.58 Þ × 10 −5 for P c ð4312Þ, P c ð4440Þ, and P c ð4457Þ, respectively, which is about 1 order larger than the present estimation.…”

“…Very recently, the LHCb Collaboration updated its analysis of the J=ψp invariant mass spectroscopy of Λ b → KJ=ψp and found three pentaquark states, which are P þ c ð4312Þ, P þ c ð4440Þ, and P þ c ð4457Þ [33]. After the new observation, some interpretation has been proposed immediately in the molecular [34][35][36][37][38][39][40][41][42][43][44][45][46][47] and pentaquark scenarios [48][49][50][51][52][53][54]. In addition, by fitting the LHCb data around 4312 MeV with the amplitudes satisfying the general principles of S-matrix theory, P c ð4312Þ is assigned as a virtual state resulting from the weak interactions ofD and Σ c [55].…”

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

“…With its unambiguous prediction of quantum numbers, our model is also quite different from most compact pentaquark scenarios, which typically allow for states with many possible quantum numbers, specifically 1=2 − , 3=2 − , and 5=2 − for S-wave states, and 1=2 þ , 3=2 þ , 5=2 þ , and 7=2 þ for P-waves [33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48]. (Although we note that some pentaquark scenarios predict a restricted spectrum, in particular, models which incorporate the coupling to mesonbaryon pairs [49], or which include additional dynamical assumptions [50].…”