2nd Hadron Spanish Network Days Universidad Complutense de Madrid September 8-9, 2016 In collaboration with A. Feijoo Aliau, A. Ramos & E. Oset
LHCb Coll., Phys.Rev.Lett. 115 (2015) 072001
LHCb Coll., Phys.Rev.Lett. 115 (2015) 072001
XIIth Quark Confinement and Hadron Spectrum Conference, Thessaloniki, Greece, Aug 29 Sept 3, 2016
Similar states have been predicted theoretically! Molecular models - Wu, Molina, Oset, Zou, PRL 105, 232001 (2010); PRC 84, 015202 (2011 - Yang, Sun, He, Liu, Zhu, Chin. Phys. C 36, 6 (2012) - Xiao, Nieves, Oset, PRD 88, 056012 (2013) - Karliner, Rosner, PRL 115, 122001 (2015) Quark models - Wang, Huang, Zhang, Zou, PRC 84, 015203 (2011) - Yuan, Wei, He, Xu, Zou, EPJA 48, 61 (2012)
Jia-Jun Wu, R. Molina, E. Oset & B. S. Zou, Phys. Rev. Lett. 105 (2010) 232001; Phys. Rev. C84 (2011) 015202
How to observe strange hidden charm pentaquarks? Chen, Geng, Liang, Oset, Wang, Xie, PRC 93, 065203 (2016)
How to observe strange hidden charm pentaquarks? Chen, Geng, Liang, Oset, Wang, Xie, PRC 93, 065203 (2016) A. Feijoo, V.K. Magas, A. Ramos & E. Oset Eur.Phys.J. C76 (2016) no.8, 446 Lu, Wang, Xie, Geng, Oset, PRD 93 (2016) 094009
Diagrams (a) and (b) have already been studied in A. Feijoo, V.K. Magas, A. Ramos & E. Oset Phys.Rev. D92 (2015) no.7, 076015 We have to add J/Ψ Λ final state interaction
Weak decay u, d - spectators
L=1 Weak decay u, d - spectators
L=1 Weak decay u, d - spectators After hadronization
Weak decay u, d - spectators After hadronization
Transition amplitude Unknown overall factor Arbitrary units [Feijoo, PRD92 (15) 076015]
Transition amplitude for (a)+(b)+(c) graphs
Meson-baryon interaction amplitudes and loop functions are taken from Feijoo, Magas, Ramos, Phys.Rev. C92 (2015) no.1, 015206 For the latest results - A. Feijoo s talk
J/Ψ Λ interaction amplitudes and loop functions are taken from Jia-Jun Wu, R. Molina, E. Oset, B. S. Zou, Phys. Rev. C84 (2011) 015202
Full transition amplitude We expect that β < 1
We consider s-wave J/Ψ Λ interaction, hence the produced pentaquark could have J = 1/2 or 3/2 For simplicity I consider now only J = 1/2 case J=3/2 pentaquark requires to implement a p-wave contribution in the weak decay mechanism Feijoo, Magas, Ramos, Oset, Eur. Phys. J. C76 (2016) no.8, 446
We consider s-wave J/Ψ Λ interaction, hence the produced pentaquark could have J = 1/2 or 3/2 For simplicity I consider now only J = 1/2 case J=3/2 pentaquark requires to implement a p-wave contribution in the weak decay mechanism Feijoo, Magas, Ramos, Oset, Eur. Phys. J. C76 (2016) no.8, 446 The double differential cross-section
Different parameterizations of the model of [Feijoo, Magas, Ramos, PRC 92 (2015) no.1,015206] Coupled-channel unitary chiral model Chiral Lagrangian up to NLO Fitted to large set of experimental data Includes reactions WT (Weinberg-Tomozawa) only LO terms in the chiral Lagrangian Model 1 includes NLO terms in the chiral Lagrangian Model 2 NLO terms + high spin resonances in KΞ channels
Model 1 Model 2 Feijoo, Magas, Ramos, Phys.Rev. C92 (2015) no.1, 015206
Different parameterizations of the model of [Feijoo, Magas, Ramos, PRC 92 (2015) no.1,015206] Coupled-channel unitary chiral model Chiral Lagrangian up to NLO Fitted to large set of experimental data Includes reactions The pentaquark peak is clearly seen over the background! WT (Weinberg-Tomozawa) only LO terms in the chiral Lagrangian Model 1 includes NLO terms in the chiral Lagrangian Model 2 NLO terms + high spin resonances in KΞ channels
Model 2 The pentaquark peak is clearly seen for reasonable variations of the resonance mass and of the coupling to J/Ψ Λ channel The pentaquark could be seen over the background for In all the unitarity approaches: PRL 105 (2010) 232001; PRC 84 (2011) 015202, Chin. Ph. C36 (2012) 6, PRD 88 (2013) 056012
Model 2 positive negative
Conclusions I Strange pentaquark molecular state is predicted in [PRL 105, 232001; PRC 84, 015202] in the range of about 4450-4650 MeV
Conclusions II Strange pentaquark molecular state is predicted in [PRL 105, 232001; PRC 84, 015202] in the range of about 4450-4650 MeV
I=0 I=0 I=0 Weak decay u, d - spectators Roca, Mai, Oset, Meißner, Eur. Phys. J. C75 (2015) no.5, 218
Model 1 Model 2
Model 3 includes Born Term contributions Born terms appear to be very important for the
Experimental data show dominance of the I=1 contribution We also observe a completely different behaviour of the I=0 channel between Models 1&2 and Model 3 Complementary experimental information about I=0 channel would be very useful
Conclusions Strange pentaquark molecular state is predicted in [PRL 105, 232001; PRC 84, 015202] in the range of about 4450-4650 MeV Work in progress
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