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Author Roca, L.; Nieves, J.; Oset, E.
Title LHCb pentaquark as a (D)over-bar*Sigma(c) – (D)over-bar*Sigma(c)* molecular state Type Journal Article
Year 2015 Publication Physical Review D Abbreviated Journal Phys. Rev. D
Volume 92 Issue 9 Pages 094003 - 6pp
Keywords
Abstract We perform a theoretical analysis of the Lambda(b) -> J/psi K(-)p reaction from where a recent LHCb experiment extracts a Lambda(1405) contribution in the K(-)p spectrum close to threshold and two baryon states of hidden charm in the J/psi p spectrum. We recall that baryon states of this type have been theoretically predicted matching the mass, width and J(P) of the experiment; concretely some states built up from the J/psi N, (D) over bar*Lambda(c), (D) over bar*Sigma(c), (D) over bar Sigma(c)* and (D) over bar*Sigma(c)* coupled channels. We assume that the observed narrow state around 4450 MeV has this nature and we are able to describe simultaneously the shapes and relative strength of the the K(-)p mass distribution close to threshold and the peak of the J/psi p distribution, with values of the J/psi p coupling to the resonance in line with the theoretical ones. The nontrivial matching of many properties gives support to a J(P) = 3/2(-) assignment to this state and to its nature as a molecular state mostly made of (D) over bar*Sigma(c) and (D) over bar*Sigma(c)*.
Address (up) [Roca, L.] Univ Murcia, Dept Fis, E-30100 Murcia, Spain
Corporate Author Thesis
Publisher Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1550-7998 ISBN Medium
Area Expedition Conference
Notes WOS:000364019700004 Approved no
Is ISI yes International Collaboration no
Call Number IFIC @ pastor @ Serial 2448
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Author Roca, L.; Oset, E.
Title Role of a triangle singularity in the pi Delta decay of N(1700)(3/2(-)) Type Journal Article
Year 2017 Publication Physical Review C Abbreviated Journal Phys. Rev. C
Volume 95 Issue 6 Pages 065211 - 8pp
Keywords
Abstract We show the important role played by the pi Delta(1232) channel in the build up of the N(1700)(3/2(-)) resonance due to the nontrivial enhancement produced by a singularity of a triangular loop. The N(1700) is one of the dynamically generated resonances produced by the coupled-channel vector-baryon interaction. The pi Delta channel was neglected in previous works but we show that it has to be incorporated into the coupled-channel formalism due to an enhancement produced by a singularity in the triangular loop with., nucleon, and p as internal loop lines and pi and Delta as external ones. The enhancement is of nonresonant origin but it contributes to the dynamical generation of the N(1700) resonance due to the nonlinear dynamics involved in the coupled-channel mechanisms. We obtain an important increase of the total width of the N(1700) resonance when the pi Delta channel is included and provide predictions for the partial widths of the N(1700) decays into VB and pi Delta.
Address (up) [Roca, L.] Univ Murcia, Dept Fis, E-30100 Murcia, Spain
Corporate Author Thesis
Publisher Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9985 ISBN Medium
Area Expedition Conference
Notes WOS:000404022100005 Approved no
Is ISI yes International Collaboration no
Call Number IFIC @ pastor @ Serial 3177
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Author Roca, L.; Oset, E.
Title On the hidden charm pentaquarks in Lambda(b) -> J/psi K- p decay Type Journal Article
Year 2016 Publication European Physical Journal C Abbreviated Journal Eur. Phys. J. C
Volume 76 Issue 11 Pages 591 - 12pp
Keywords
Abstract In a previous work we presented a theoretical analysis of the Lambda(b) -> J/psi K- p reaction based on which a recent experiment by the LHCb collaboration at CERN claimed the existence of two hidden charm pentaquarks, P-c(4380)(+) and P-c(4450)(+). In that work we focused only on the Lambda(1405) and P-c(4450)(+) signals and discussed the possible explanation of this pentaquark state within the picture of a dynamical meson-baryon molecule made up mostly from (D) over bar*Sigma(c) and (D) over bar*Sigma(c)* components. In the present work we improve upon the previous one by considering the total K- p and J/psi p data including all the relevant resonances contributing to the spectra, and discuss the possible nature of both P-c(4380)(+) and P-c(4450)(+). We also discuss several important topics, like the effect of the contact term in the reaction, the viability of reproducing the data without the P-c(4380)(+) and the possible quantum number assignment to these pentaquarks.
Address (up) [Roca, L.] Univ Murcia, Dept Fis, E-30100 Murcia, Spain, Email: luisroca@um.es
Corporate Author Thesis
Publisher Springer Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1434-6044 ISBN Medium
Area Expedition Conference
Notes WOS:000399930700001 Approved no
Is ISI yes International Collaboration no
Call Number IFIC @ pastor @ Serial 3065
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Author Roca, L.; Song, J.; Oset, E.
Title Molecular pentaquarks with hidden charm and double strangeness Type Journal Article
Year 2024 Publication Physical Review D Abbreviated Journal Phys. Rev. D
Volume 109 Issue 9 Pages 094005 - 8pp
Keywords
Abstract We analyze theoretically the coupled-channel meson-baryon interaction with global flavor c<overline>cssn and c<overline>csss, where mesons are pseudoscalars or vectors, and baryons have JP = 1/2+ or 3/2+. The aim is to explore whether the nonlinear dynamics inherent in the unitarization process within coupled channels can dynamically generate double- and triple-strange pentaquark-type states (Pcss and Pcsss, respectively), for which there is no experimental evidence to date. We evaluate the s-wave scattering matrix by implementing unitarity in coupled channels, using potential kernels obtained from t-channel vector meson exchange. The required PPV and VVV vertices are obtained from Lagrangians derived through appropriate extensions of the local hidden gauge symmetry approach to the charm sector, while capitalizing on the symmetry of the spin and flavor wave function to evaluate the BBV vertex. We find four different poles in the double strange sector, some of them degenerate in spin. For the triple-strange channel, we find the meson-baryon interaction insufficient to generate a bound or resonance state through the unitary coupled-channel dynamics.
Address (up) [Roca, L.] Univ Murcia, Dept Fis, E-30100 Murcia, Spain, Email: luisroca@um.es;
Corporate Author Thesis
Publisher Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2470-0010 ISBN Medium
Area Expedition Conference
Notes WOS:001224715500002 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 6135
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Author Roca, L.; Mai, M.; Oset, E.; Meissner, U.G.
Title Predictions for the Lambda(b) -> J/psi Lambda (1405) decay Type Journal Article
Year 2015 Publication European Physical Journal C Abbreviated Journal Eur. Phys. J. C
Volume 75 Issue 5 Pages 218 - 9pp
Keywords
Abstract We calculate the shape of the pi Sigma and (K) over bar N invariant mass distributions in the Lambda(b) -> J/psi pi Sigma and Lambda(b) -> J/psi (K) over bar N decays that are dominated by the Lambda (1405) resonance. The weak interaction part is the same for both processes and the hadronization into the different meson-baryon channels in the final state is given by symmetry arguments. The most important feature is the implementation of the meson-baryon final-state interaction using two chiral unitary models from different theoretical groups. Both approaches give a good description of antikaon-nucleon scattering data, the complex energy shift in kaonic hydrogen and the line shapes of pi Sigma K in photoproduction, based on the two-pole scenario for the Lambda (1405). We find that this reaction reflects more the higher mass pole and we make predictions of the line shapes and relative strength of the meson-baryon distributions in the final state.
Address (up) [Roca, L.] Univ Murcia, Dept Fis, Murcia 30100, Spain, Email: luisroca@um.es;
Corporate Author Thesis
Publisher Springer Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1434-6044 ISBN Medium
Area Expedition Conference
Notes WOS:000355678900006 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 2271
Permanent link to this record