Study of BBˉ∗B\bar{B}^* and B∗Bˉ∗B^*\bar{B}^* interactions in I=1I=1 and relationship to the Zb(10610)Z_b(10610), Zb(10650)Z_b(10650) states

We use the local hidden gauge approach in order to study the $B\bar{B}^*$ and $B^*\bar{B}^*$ interactions for isospin I=1. We show that both interactions via one light meson exchange are not allowed by OZI rule and, for that reason, we calculate the contributions due to the exchange of two pions, interacting and noninteracting among themselves, and also due to the heavy vector mesons. Then, to compare all these contributions, we use the potential related to the heavy vector exchange as an effective potential corrected by a factor which takes into account the contribution of the others light mesons exchange. In order to look for poles, this effective potential is used as the kernel of the Bethe-Salpeter equation. As a result, for the $B\bar{B}^*$ interaction we find a loosely bound state with mass in the range $10587-10601$ MeV, very close to the experimental value of the $Z_b(10610)$ reported by Belle Collaboration. For the $B^*\bar{B}^*$ case, we find a cusp at $10650$ MeV for all spin $J=0,\,1,\,2$ cases.Comment: 23 pages, 20 figure

Analytical r-mode solution with gravitational radiation reaction force

We present and discuss the analytical r-mode solution to the linearized hydrodynamic equations of a slowly rotating, Newtonian, barotropic, non-magnetized, perfect-fluid star in which the gravitational radiation reaction force is present.Comment: 3 pages, in Proceedings of the 5th International Workshop "New Worlds in Astroparticle Physics", Faro, Portugal, 8-10 January 200

Y(4260) as a mixed charmonium-tetraquark state

Using the QCD sum rule approach we study the Y(4260) state assuming that it can be described by a mixed charmonium-tetraquark current with $J^{PC}=1^{--}$ quantum numbers. For the mixing angle around $\theta \approx (53.0\pm 0.5)^{0}$, we obtain a value for the mass which is in good agreement with the experimental mass of the Y(4260). However, for the decay width we find the value \Ga_Y \approx (1.0\pm 0.2) MeV which is not compatible with the experimental value \Ga \approx (88\pm 23) MeV. Therefore, we conclude that, although we can explain the mass of the Y(4260), this state cannot be described as a mixed charmonium-tetraquark state since, with this assumption, we can not explain its decay width.Comment: 9 pages, 6 figure

Relation between Tcc,bbT_{cc,bb} and Xc,bX_{c,b} from QCD

We have studied, using double ratio of QCD (spectral) sum rules, the ratio between the masses of $T_{cc}$ and X(3872) assuming that they are respectively described by the $D-{D}^*$ and $D-\bar{D}^*$ molecular currents. We found (within our approximation) that the masses of these two states are almost degenerate. Since the pion exchange interaction between these mesons is exactly the same, we conclude that if the observed X(3872) meson is a $D\bar{D}^*+c.c.$ molecule, then the $DD^*$ molecule should also exist with approximately the same mass. An extension of the analysis to the $b$-quark case leads to the same conclusion. We also study the SU(3) breakings for the $T^s_{QQ}/T_{QQ}$ mass ratios. Motivated by the recent Belle observation of two $Z_b$ states, we revise our determination of $X_b$ by combining results from exponential and FESR sum rules.Comment: revised version to appear on Phys. Lett.

Thick Braneworlds and the Gibbons-Kallosh-Linde No-go Theorem in the Gauss-Bonnet Framework

The sum rules related to thick braneworlds are constructed, in order to encompass Gauss-Bonnet terms. The generation of thick branes is hence proposed in a periodic extra dimension scenario, what circumvents the Gibbons-Kallosh-Linde no-go theorem in this context.Comment: 6 pages, to appear in the EPL. arXiv admin note: text overlap with arXiv:1406.632