Statut  Confirmé 
Série  IPNX 
Domaines  hepph 
Date  Jeudi 1 Juin 2017 
Heure  11:00 
Institut  IPN 
Salle  Salle A402 
Nom de l'orateur  Pavon Valderrama 
Prenom de l'orateur  Manuel 
Addresse email de l'orateur  
Institution de l'orateur  Beihang University, Beijing 
Titre  Scale Invariance in Heavy Hadron Molecules 
Résumé  When pions are exchanged almost onshell the range of hadron interactions is unusually long, opening the possibility to interesting phenomena. One example is the Lambda_c(2590) > Sigma_c pi transition, which is mediated by the emission of an Swave pion near the massshell. Other more wellknown example is the D* > D \pi transition, though in this case the pion is in Pwave. When we combine both vertices to obtain the Lambda_c(2590) Dbar > Sigma_c D*bar potential, the result is a longrange inverse square potential. With this potential the Lambda_c(2590) Dbar  Sigma_c D*bar system becomes scale invariant, i.e. it is symmetric under dilatations, a property which is also shared by two and threebody systems with large scattering lengths. This symmetry is however anomalous and is broken by the spectrum, which can at most display a discrete form of it if the interaction is strong enough. We explore where this is the case in the Lambda_c(2590) Dbar  Sigma_c D*bar system, which is a candidate for a molecular explanation of the recently observed heavy pentaquark Pc(4450)+, or in other hadron molecules. In addition we consider what happens when we have a Lambda_c(2590) Sigma_c (or anti Sigma_c) molecule. In this latter case the potential is of the 1/r type, but which an unusual longrange, behaving as Coulomb for typical hadronic scales. The interesting point here is that this coulomblike potential probably holds an Swave shallow state, making for a nice prediction of a nearthreshold hadron molecule. 
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