Universidad Complutense de Madrid September 8-9, In collaboration with A. Feijoo Aliau, A. Ramos & E. Oset

Transcription

1 2nd Hadron Spanish Network Days Universidad Complutense de Madrid September 8-9, 2016 In collaboration with A. Feijoo Aliau, A. Ramos & E. Oset

2 LHCb Coll., Phys.Rev.Lett. 115 (2015)

3 LHCb Coll., Phys.Rev.Lett. 115 (2015)

4 XIIth Quark Confinement and Hadron Spectrum Conference, Thessaloniki, Greece, Aug 29 Sept 3, 2016

5 Similar states have been predicted theoretically! Molecular models - Wu, Molina, Oset, Zou, PRL 105, (2010); PRC 84, ( Yang, Sun, He, Liu, Zhu, Chin. Phys. C 36, 6 (2012) - Xiao, Nieves, Oset, PRD 88, (2013) - Karliner, Rosner, PRL 115, (2015) Quark models - Wang, Huang, Zhang, Zou, PRC 84, (2011) - Yuan, Wei, He, Xu, Zou, EPJA 48, 61 (2012)

6 Jia-Jun Wu, R. Molina, E. Oset & B. S. Zou, Phys. Rev. Lett. 105 (2010) ; Phys. Rev. C84 (2011)

7 How to observe strange hidden charm pentaquarks? Chen, Geng, Liang, Oset, Wang, Xie, PRC 93, (2016)

8 How to observe strange hidden charm pentaquarks? Chen, Geng, Liang, Oset, Wang, Xie, PRC 93, (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)

9 Diagrams (a) and (b) have already been studied in A. Feijoo, V.K. Magas, A. Ramos & E. Oset Phys.Rev. D92 (2015) no.7, We have to add J/Ψ Λ final state interaction

10 Weak decay u, d - spectators

11 L=1 Weak decay u, d - spectators

12 L=1 Weak decay u, d - spectators After hadronization

13 Weak decay u, d - spectators After hadronization

14 Transition amplitude Unknown overall factor Arbitrary units [Feijoo, PRD92 (15) ]

15 Transition amplitude for (a)+(b)+(c) graphs

16 Meson-baryon interaction amplitudes and loop functions are taken from Feijoo, Magas, Ramos, Phys.Rev. C92 (2015) no.1, For the latest results - A. Feijoo s talk

17 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)

18 Full transition amplitude We expect that β < 1

19 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

20 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

21 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

22 Model 1 Model 2 Feijoo, Magas, Ramos, Phys.Rev. C92 (2015) no.1,

23 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

24 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) ; PRC 84 (2011) , Chin. Ph. C36 (2012) 6, PRD 88 (2013)

25 Model 2 positive negative

26 Conclusions I Strange pentaquark molecular state is predicted in [PRL 105, ; PRC 84, ] in the range of about MeV

27 Conclusions II Strange pentaquark molecular state is predicted in [PRL 105, ; PRC 84, ] in the range of about MeV

28 I=0 I=0 I=0 Weak decay u, d - spectators Roca, Mai, Oset, Meißner, Eur. Phys. J. C75 (2015) no.5, 218

29 Model 1 Model 2

30 Model 3 includes Born Term contributions Born terms appear to be very important for the

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32 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

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34 Conclusions Strange pentaquark molecular state is predicted in [PRL 105, ; PRC 84, ] in the range of about MeV Work in progress

35 BACKUP SLIDES

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