0000000001045875
AUTHOR
Raquel Molina Peralta
Radiative decays of the Y(3940), Z(3930) and the X(4160) as dynamically generated resonances
We study the radiative decay properties of the charmonium-like X, Y and Z mesons generated dynamically from vector meson-vector meson interaction in the framework of a unitarized hidden-gauge formalism. In the present work we calculate the one- and two-photon decay widths of the hidden-charm Y(3940), Z(3930) (or X(3915)) and X(4160) mesons in the framework of the vector meson dominance formalism. We obtain good agreement with experiment in case of the two photon width of the X(3915) which we associate with the $2^+$ resonance that we find at 3922 MeV.
(K)over-bar* mesons in dense matter
We study the properties of (K) over bar* mesons in nuclear matter using a unitary approach in coupled channels within the framework of the local hidden gauge formalism and incorporating the (K) over bar pi decay channel in matter. The in-medium (K) over bar *N interaction accounts for Pauli blocking effects and incorporates the (K) over bar* self-energy in a self-consistent manner. We also obtain the (K) over bar* (off-shell) spectral function and analyze its behavior at finite density and momentum. At a normal nuclear matter density, the (K) over bar* meson feels a moderately attractive potential, while the (K) over bar* width becomes five times larger than in free space. We estimate the t…
Dynamically generated N* and Lambda* resonances in the hidden charm sector around 4.3 GeV
The interactions of $\bar{D}\Sigma_{c}$-$\bar D\Lambda_c$, $\bar{D}^{*}\Sigma_{c}$-$\bar D^*\Lambda_c$, and related strangeness channels, are studied within the framework of the coupled channel unitary approach with the local hidden gauge formalism. A series of meson-baryon dynamically generated relatively narrow $N^*$ and $\Lambda^*$ resonances are predicted around 4.3 GeV in the hidden charm sector. We make estimates of production cross sections of these predicted resonances in $\bar{p} p $ collisions for PANDA at the forthcoming FAIR facility.
Y(3940), Z(3930), and the X(4160) as dynamically generated resonances from the vector-vector interaction
We study the vector-vector interaction within the framework of the hidden gauge formalism for the channels with quantum numbers charm C=0 and strangeness S=0 in the energy region around 4000 MeV. By looking for poles in the complex plane we find three resonances that could be identified by the mass, width, and quantum numbers with the Y(3940), Z(3940), and X(4160), these poles appear with isospin I=0 and J(PC)=0(++), 2(++) and 2(++), respectively. Whereas the Y(3940) and Z(3940) are coupled more strongly to (DD*)-D-*, the X(4160) is basically a (DsDs*)-D-* molecular state. Another two extra resonances appear in our approach with I=0, 1 and J(PC)=1(+-), 2(++) which are not found in the PDG w…
Predictions for the X(YZ) and X(YZ) with X(4160), Y(3940), Z(3930)
We investigate the decay of and with R being the , , resonances. Under the assumption that these states are dynamically generated from the vector-vector interaction, as has been concluded from several theoretical studies, we use a reaction mechanism of quark production at the elementary level, followed by hadronization of one final pair into two vectors and posterior final state interaction of this pair of vector mesons to produce the resonances. With this procedure we are able to predict five ratios for these decays, which are closely linked to the dynamical nature of these states, and also predict the order of magnitude of the branching ratios which we find of the order of , well within t…
Nuclear medium effects on the (K)over-bar* meson
The K¯∗ meson in dense matter is analyzed by means of a unitary approach in coupled channels based on the local hidden gauge formalism. The K¯∗ self-energy and the corresponding K¯∗ spectral function in the nuclear medium are obtained. We observe that the K¯∗ develops a width in matter up to five times bigger than in free space. We also estimate the transparency ratio of the γA→K+K∗−A′ reaction. This ratio is an excellent tool to detect experimentally modifications of the K¯∗ meson in dense matter.
J/\psi depletion in a nuclear medium
In this talk, we have taken into account the main decay channel of J/ψ when travelling inside a nucleus. In analogy to all vector mesons in SU(3), where the main decay channel is to two pseudoscalars, in the case of the J/ψ the meson meson channel to which it couples strongly is DD. Taking this into account we study the J/ψN → DΛc and J/ψN → DΣc mediated by D-exchange. To obtain the couplings we use an extension to SU(4) of the local hidden gauge Lagrangians as done in [1]. Analogously, we consider the mechanisms where the exchanged D collides with a nucleon and gives πΛc or πΣc. The sum of these channels produces a J/ψN inelastic cross section which is larger than the elastic one and is re…
rho rho interaction in the hidden gauge formalism and the f(0)(1370) and f(2)(1270) resonances
We have studied the interaction of vectors mesons within the hidden gauge formalism and applied it to the particular case of the ρρ interaction. We find a strong attraction in the isospin, spin channels I,S=0,0 and 0,2, which is enough to bind the ρρ system. We also find that the attraction in the I,S=0,2 channel is much stronger than in the 0,0 case. The states develop a width when the ρ mass distribution is considered, and particularly when the ππ decay channel is turned on. Using a regularization scheme with cut offs of natural size, we obtain results in fair agreement with the mass and the width of the f0(1370) and f2(1270) meson states, providing a natural explanation of why the tensor…
X(3872) -> J/psi gamma decay in the D(D)over-bar* molecular picture
From a picture of the X(3872) where the resonance is a bound state of D (D) over bar*- c.c., we evaluate the decay width into the J/psi gamma channel, which is sensitive to the internal structure of this state. For this purpose we evaluate the loops through which the X(3872) decays into its components, and the J/psi and the photon are radiated from these components. We use the local hidden gauge approach extrapolated to SU(4) with a particular SU(4) breaking. The radiative decay involves anomalous couplings, and we obtain acceptable values which are compared to experiments and results of other calculations. Simultaneously, we evaluate the decay rate for the X(3872) into J/psi omega and J/ps…
gamma gamma decay of the f(0)(1370) and f(2)(1270) resonances in the hidden gauge formalism
Using recent results obtained within the hidden gauge formalism for vector mesons, in which the f0(1370) and f2(1270) resonances are dynamically generated resonances from the ρρ interaction, we evaluate the radiative decay of these resonances into γγ. We obtain results for the width in good agreement with the experimental data for the f2(1270) state and a width about a factor five smaller for the f0(1370) resonance, which would agree with preliminary results from the Belle collaboration, hinting at an order of magnitude smaller width for this resonance than for the f2(1270).