P. G. Ortega

Coupled channel approach to the structure of the X(3872)

We have performed a coupled channel calculation of the 1{sup ++} cc sector including qq and DD* molecular configurations. The calculation was done within a constituent quark model which successfully describes the meson spectrum, in particular, the cc 1{sup --} sector. Two and four-quark configurations are coupled using the {sup 3}P{sub 0} model. The elusive X(3872) meson appears as a new state with a high probability for the DD* molecular component. When the mass difference between neutral and charged states is included, a large D{sup 0}D*{sup 0} component is found which dominates for large distances and breaks isospin symmetry in the physical state. The original cc(2{sup 3}P{sub 1}) state acquires a sizable DD* component and can be identified with the X(3940). We study the B{yields}K{pi}{sup +{pi}-}J/{psi} and B{yields}KD{sup 0}D*{sup 0} decays, finding a good agreement with Belle and BABAR experimental data.

Quark model description of the Λc(2940)+ as a molecular D⁎N state and the possible existence of the Λb(6248)

Abstract The Λ c ( 2940 ) + baryon is studied in a constituent quark model as a molecular state composed by nucleons and D ⁎ mesons. A bound state with the right binding energy is found for the J π = 3 2 − channel. The partial widths Λ c ( 2940 ) + → N D and Λ c ( 2940 ) + → Σ c π are calculated and the results are consistent with the experimental data. Additionally a bottom partner B ¯ ⁎ N is predicted with a mass of 6248 MeV / c 2 .

Bottom and charm mass determinations from global fits to \( Q\overline{Q} \) bound states at N3LO

A bstractThe bottomonium spectrum up to n = 3 is studied within Non-Relativistic Quantum Chromodynamics up to N3LO. We consider finite charm quark mass effects both in the QCD potential and the MS¯

c^2

\overline{\mathrm{MS}}

X(3915)/X(3930)

-pole mass relation up to third order in the Y-scheme counting. The u = 1/2 renormalon of the static potential is canceled by expressing the bottom quark pole mass in terms of the MSR mass. A careful investigation of scale variation reveals that, while n = 1, 2 states are well behaved within perturbation theory, n = 3 bound states are no longer reliable. We carry out our analysis in the nℓ = 3 and nℓ = 4 schemes and conclude that, as long as finite mc effects are smoothly incorporated in the MSR mass definition, the difference between the two schemes is rather small. Performing a fit to bb¯

Quark model description of the \Lambda_c(2940)^+ as a molecular D^*N state and the possible existence of the \Lambda_b(6248)

b\overline{b}