Production of $P_c$ states in ${\Lambda }_b$ decays

Abstract

We develop a model for the production of the Pc states observed at LHCb in Lambdab - Jpsi p K- decays. With fewer parameters than other approaches, we obtain excellent fits to the Jpsi-p invariant mass spectrum, capturing both the prominent peaks, and broader features over the full range of invariant mass. A distinguishing feature of our model is that whereas Pc(4312), Pc(4380), and Pc(4440) are resonances with Sigmac*-D* constituents, the nature of Pc(4457) is quite different, and can be understood either as a Sigmac-D* threshold cusp, a Lambdac(2595)-D enhancement due to the triangle singularity, or a Lambdac(2595)-D resonance. We propose experimental measurements that can discriminate among these possibilities. Unlike in other models, our production mechanism respects isospin symmetry and the empirical dominance of colour-enhanced processes in weak decays, and additionally gives a natural explanation for the overall shape of the data. Our model is consistent with experimental constraints from photoproduction and Lambdab - Lambdac-D(*)0 K- decays and it does not imply the existence of partner states whose apparent absence in experiments is unexplained in other models.

arXiv comment51 pages, 13 figures. Additional discussion and results. Version to appear in PRD

References in corpus (60)

• Averages of $b$-hadron, $c$-hadron, and $\tau$-lepton properties as of summer 2016
• Observation of $J/\psi p$ resonances consistent with pentaquark states in ${\Lambda }_b^0\to J/\psi K^{-}p$ decays
• Higher Charmonia
• Observation of a narrow pentaquark state, $P_c(4312{)}^{+}$, and of two-peak structure of the $P_c(4450{)}^{+}$
• The New Heavy Mesons: A Status Report
• On the Mechanism of Open-Flavor Strong Decays
• New Exotic Meson and Baryon Resonances from Doubly-Heavy Hadronic Molecules
• Threshold cusps and triangle singularities in hadronic reactions
• Identifying exotic hidden-charm pentaquarks
• How to reveal the exotic nature of the P_c(4450)
• Higher Quarkonia
• Dynamically generated $N^{\ast }$ and ${\Lambda }^{\ast }$ resonances in the hidden charm sector around 4.3 GeV
• Emergence of a complete heavy-quark spin symmetry multiplet: seven molecular pentaquarks in light of the latest LHCb analysis
• Understanding the newly observed heavy pentaquark candidates
• Strong LHCb evidence supporting the existence of the hidden-charm molecular pentaquarks
• $\bar{D}{\Sigma }_c^{\ast }$ and ${\bar{D}}^{\ast }{\Sigma }_c$ interactions and the LHCb hidden-charmed pentaquarks
• Combining heavy quark spin and local hidden gauge symmetries in the dynamical generation of hidden charm baryons
• First measurement of near-threshold J/$\psi$ exclusive photoproduction off the proton
• Strong Decays of Strange Quarkonia
• Study of $P_c(4457)$, $P_c(4440)$, and $P_c(4312)$ in a quasipotential Bethe-Salpeter equation approach
• Heavy quark spin symmetric molecular states from ${\bar{D}}^{(\ast )}{\Sigma }_c^{(\ast )}$ and other coupled channels in the light of the recent LHCb pentaquarks
• A Discussion on Triangle Singularities in the ${\Lambda }_b\to J/\psi K^{-}p$ Reaction
• Interpretation of the LHCb $P_c$ States as Hadronic Molecules and Hints of a Narrow $P_c(4380)$
• Phenomenology of $P_c(4380{)}^{+}$, $P_c(4450{)}^{+}$ and related states
• Model-independent evidence for $J/\psi p$ contributions to ${\Lambda }_b^0\to J/\psi p{K}^{-}$ decays
• Anatomy of the newly observed hidden-charm pentaquark states: $P_c(4312)$, $P_c(4440)$ and $P_c(4457)$
• Nonleptonic Weak Decays of Bottom Baryons
• Molecular Interpretation of the $P_c(4440)$ and $P_c(4457)$ States
• Hidden charm N and Delta resonances with heavy-quark symmetry
• Revisiting the nature of the $P_c$ pentaquarks
• Singly Cabibbo-suppressed hadronic decays of ${\Lambda }_c^{+}$
• Remarks on the $P_c$ structures and triangle singularities
• One pion exchange and the quantum numbers of the Pc(4440) and Pc(4457) pentaquarks
• Decays of $P_c$ into $J/\psi N$ and ${\eta }_{c}N$ with heavy quark spin symmetry
• Analysis of Two-Body Decays of Charmed Baryons Using the Quark-Diagram Scheme
• Coupled channel analysis of molecule picture of $P_c(4380)$
• Hidden-charm and bottom meson-baryon molecules coupled with five-quark states
• Molecular states from ${\Sigma }_c^{(\ast )}{\bar{D}}^{(\ast )}-{\Lambda }_c{\bar{D}}^{(\ast )}$ interaction
• Hidden-charm pentaquarks as a meson-baryon molecule with coupled channels for ${\bar{D}}^{(\ast )}{\Lambda }_{\mathrm{c}}$ and ${\bar{D}}^{(\ast )}{\Sigma }_{\mathrm{c}}^{(\ast )}$
• Some decay properties of hidden-charm pentaquarks as baryon-meson molecules
• Nonleptonic two-body decays of single heavy baryons ${\Lambda }_Q$, ${\Xi }_Q$, and ${\Omega }_Q$ $(Q=b,c)$ induced by $W$ emission in the covariant confined quark model
• Coupled-channel effects of the ${\Sigma }_c^{(\ast )}{\bar{D}}^{(\ast )}$-${\Lambda }_c(2595)\bar{D}$ system and molecular nature of the $P_c$ pentaquark states from one-boson exchange model
• Structure and decays of hidden heavy pentaquarks
• A diagrammatic analysis of two-body charmed baryon decays with flavor symmetry
• $P_c(4312{)}^{+}$, $P_c(4380{)}^{+}$, and $P_c(4457{)}^{+}$ as double triangle cusps
• The hidden charm pentaquarks are the hidden color-octet $uud$ baryons?
• Dalitz plot distributions in presence of triangle singularities
• The semi-leptonic and non-leptonic weak decays of ${\Lambda }_b^0$
• Recently observed $P_c$ as molecular states and possible mixture of $P_c(4457)$
• Discriminating among interpretations for the $X(2900)$ states
• Hidden Charm Pentaquark $P_c(4380)$ and Doubly Charmed Baryon ${\Xi }_{cc}^{\ast }(4380)$ as Hadronic Molecule States
• Pole analysis on the hadron spectroscopy of ${\Lambda }_b\to J/\Psi p{K}^{-}$
• Scale Invariance in Heavy Hadron Molecules
• Heavy-hadron molecules from light-meson-exchange saturation
• Experimental constraints on the properties of $P_c$ states
• Fragmentation fractions of two-body b-baryon decays
• Charmful two-body anti-triplet $b$-baryon decays
• Dynamics of hadron strong production and decay
• Angular momentum coefficients for meson strong decay and unquenched quark models
• Heavy quark spin multiplet structure of ${\bar{P}}^{(\ast )}{\Sigma }_Q^{(\ast )}$ molecular states

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