Abstract: We evaluate the contribution to the X(3872) width from a triangle mechanism in which the X decays into D0D<overbar></mml:mover>0-cc, then the D0(D<overbar></mml:mover>0) decays into D0 pi 0 (D<overbar></mml:mover>0 pi 0) and the D0D<overbar></mml:mover>0 fuse to produce pi+pi-. This mechanism produces an asymmetric peak from a triangle singularity in the pi+pi- invariant mass with a shape very sensitive to the X mass. We evaluate the branching ratios for a reaction where this effect can be seen in the B--> K-pi 0 pi+pi- reaction and show that the determination of the peak in the invariant mass distribution of pi <mml:mo>+pi <mml:mo>- is all that is needed to determine the X mass. Given the present uncertainties in the X mass, which do not allow to know whether the D<mml:mo>0<mml:mover accent=“true”>D<mml:mo stretchy=“false”><overbar></mml:mover>0 state is bound or not, measurements like the one suggested here should be most welcome to clarify this issue.

Abstract: We have done a study of the B--> K-pi X-0(3872) reaction by means of a triangle mechanism via the chain of reactions: B--> K-D*(0);(D) over bar*(0); D*(0)-> pi D-0(0); D-0(D) over bar*(0)-> X(3872). We show that this mechanism generates a triangle singularity in the pi X-0(3872) invariant mass for a very narrow window of the X(3872) mass, around the present measured values, and show that the peak positions and the shape of the mass distributions arc sensitive to the X(3872) mass, such that a measurement of the reaction can serve to improve on the present values of this mass. In particular, we point out that the X(3872) mass relative to the D-0(D) over bar*(0) threshold may be extracted from the asymmetry of the pi X-0 line shape.

Abstract: We observe that four peaks seen in the high energy part of the Omega(b) spectrum of the recent LHCb experiment are in remarkable agreement with predictions made for molecular Omega(b) states stemming from the meson-baryon interaction, with an approach that applied to the Omega(c) states gives rise to three states in good agreement with experiment in masses and widths. While the statistical significance of the peaks prevents us from claims of states at the present time, the agreement found should be an incentive to look at this experiment with increased statistics to give an answer to this suggestive idea.

Abstract: We have evaluated the decay modes of the Upsilon(4s), Upsilon(3d), Upsilon(5s), Upsilon(6s) states into B (B) over bar, B (B) over bar* + c.c., B* (B) over bar*, B-s(B) over bar (s), B-s(B) over bar (s)* + c.c., B-s* (B) over bar (s)* using the P-3(0) model to hadronize the bb vector seed, fitting some parameters to the data. We observe that the Upsilon(4s) state has an abnormally large amount of mesonmeson components in the wave function, while the other states are largely b (b) over bar. We predict branching ratios for the different decay channels which can be contrasted with experiment for the case of the Upsilon(5s) state. While globally the agreement is fair, we call the attention to some disagreement that could be a warning for the existence of more elaborate components in the state.

Abstract: We have studied the meson-baryon interaction in coupled channels with the same quantum numbers of Xi bc. The interaction is attractive in some channels and of sufficient intensity to lead to bound states or resonances. We use a model describing the meson-baryon interaction based on an extrapolation of the local hidden gauge approach to the heavy sector, which has been successfully used in predicting omega c and hidden charm states. We obtain many states, some of them narrow or with zero width, as a consequence of the interaction, which qualify as molecular states in those channels. The success in related sectors of the picture used should encourage the experimental search for such states.