Suppressed decay into open charm for the Y(4260) being an hybrid

We investigate the Y(4260) resonance recently discovered by the Babar collaboration. We propose the observation of its decay into J/psi pi pi and its non observation into open charm as a consequence of it being a charmonium hybrid state with a magnetic constituent gluon. We prove a selection rule forbidding its decay into two S-wave charmed mesons in any potential model. We suggest a generalisation of the selection rule based only on the heavy quark nature of the charm.Comment: 5 page

S-wave and P-wave non-strange baryons in the potential model of QCD

In this paper, we study the nucleon energy spectrum in the ground-state (with orbital momentum L=0) and the first excited state (L=1). The aim of this study is to find the mass and mixing angles of excited nucleons using a potential model describing QCD. This potential is of the "Coulombian + linear" type and we take into account some relativistic effects, namely we use essentially a relativistic kinematic necessary for studying light flavors. By this model, we found the proton and $\Delta (1232)$ masses respectively equal to ($968MeV$, $1168MeV$), and the masses of the excited states are between $1564MeV$ and $1607MeV$.Comment: 26 pages, 1 figur

The decay of the observed JPC=1−+J^{PC}=1^{-+} (1400) and JPC=1−+J^{PC}=1^{-+}(1600) hybrid candidates

We study the possible interpretation of the two exotic resonances $J^{PC}= 1^{-+}$ at 1400 and 1600 MeV, claimed to be observed by BNL, decaying respectively into $\eta\pi$, $\eta'\pi$, $f_{1}\pi$ and $\rho\pi$. These objects are interpreted as hybrid mesons, in the quark-gluon constituent model using a chromoharmonic confining potentiel. The quantum numbers $J^{PC}I^{G} = 1^{-+} 1^{-}$ can be considered in a constituent model as an hybrid meson ($q \bar q g$). The lowest $J^{PC}= 1^{-+}$states may be built in two ways : $l_{g}$=1 (gluon-excited) corresponding to an angular momentum between the gluon and ($q \bar q$) system, while $l_{q \bar q}=1$ (quarks-excited) corresponds to an angular momentum between $q$ and $\bar q$. For the gluon-excited mode $1^{-+}$ hybrids, we find the decay dominated by the $b_{1}\pi$ channel, and by the $\rho \pi$ channel for the quark-excited mode. In our model, neither the quark-excited nor the gluon-excited $1^{-+}$ (1400 MeV) hybrids can decay into $\eta\pi$ and $\eta'\pi$, in contradiction with experiment. Hence, the 1400 MeV resonance seems unlikely to be an hybrid state. The $1^{-+}$ (1600 MeV) gluon-excited hybrid is predicted with too large a total decay width, to be considered as an hybrid candidate. On the contrary the quark-excited mode has a total decay width around 165 MeV, with a $\rho \pi$ preferred decay channel, in agreement with BNL. Our conclusion is that {\it{this resonance may be considered as a hybrid meson in the quark-excited mode}}Comment: 13 pages, 1 figur

Analysis and Behavior of a Rigid Foundation Massif under the Effect of Vibrations (Application of Barakan Method)

This communication proposes a count mode of a rigid foundation massif frequencies, relaxing on a homogeneous soil, semi-infinite having an elastic linear behavior. Several data programs process using the finite elements method, are proposed for the dynamic analysis. Nevertheless, these programs don’t appear the physical phenomenon yielded, they depend on data introduced by the user and are applicable only for the elastic foundation massifs. The BARKAN method is an analytic one that appears the physical behavior of the different displacements and their coupling modes, the involvement of soil by its different dynamic stiffness modules, as well as a constant verification of its application. Well, it remains an approached method because it doesn’t exist an exact count method currently