24,004 research outputs found
Study of and interactions in and relationship to the , states
We use the local hidden gauge approach in order to study the and
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 interaction we find
a loosely bound state with mass in the range MeV, very close to
the experimental value of the reported by Belle Collaboration. For
the case, we find a cusp at MeV for all spin
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
quantum numbers. For the mixing angle around , 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 and from QCD
We have studied, using double ratio of QCD (spectral) sum rules, the ratio
between the masses of and X(3872) assuming that they are respectively
described by the and 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
molecule, then the molecule should also exist with approximately the
same mass. An extension of the analysis to the -quark case leads to the same
conclusion. We also study the SU(3) breakings for the mass
ratios. Motivated by the recent Belle observation of two states, we
revise our determination of 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
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