125904516
Investigating the $D^{*}\rho$ system using QCD sum rules
53709968
Theoretical study of incoherent φ photoproduction on a deuteron target
We study the photoproduction of φ mesons in deuteron, paying attention to the modification of the cross-section from bound protons to the free ones. For this purpose we take into account Fermi motion in single scattering and rescattering of φ to account for φ absorption on a second nucleon as well as the rescattering of the proton on the neutron. We find that the contribution of the double scattering for φ is much smaller than the typical cross-section of γp → φp in free space, which implies a very small screening of the φ production in deuteron. The contribution from the proton rescattering, on the other hand, is found to be not negligible compared to the cross-section of γp → φp in free space, and leads to a moderate reduction of the φ photoproduction cross-section on a deuteron at forward angles if the LEPS set-up is taken into account. The Fermi motion allows contribution of the single scattering in regions forbidden by phase-space in the free case. In particular, we find that for momentum transfer squared close to the maximum value, the Fermi motion changes drastically the shape of dσ/dt, to the point that the ratio of this cross-section to the free one becomes very sensitive to the precise value of t chosen, or the size of the bin used in an experimental analysis. Hence, this particular region of t does not seem to be the most indicated to find effects of a possible φ absorption in the deuteron. This reaction is studied theoretically as a function of t and the results are contrasted with recent experiments at LEPS and Jefferson Lab. The effect of the experimental angular cuts at LEPS is also discussed, providing guidelines for future experimental analyses of the reaction.
118615184
$X(3872)$ production in high energy heavy ion collisions
We show the results obtained for the cross sections of the processes D̄D, D̄∗D, D̄∗D∗ → πX(3872), information which is necessary to determine the X(3872) abundance in heavy ion collisions. Our formalism is based on the generation of X(3872) from the interaction of the hadrons D̄0D∗0−c.c, D−D∗+−c.c and D− s D∗+ s −c.c an the calculation of the XD̄∗D∗ anomalous vertex considering X(3872) as a molecule of the above hadrons channels.
118784454
Interaction of vector mesons with baryons and vectors in the nuclear medium
In this talk we present a short review of recent developments concerning the interaction of vector mesons with baryons and with nuclei. We begin with the hidden gauge formalism for the interaction of vector mesons, then review results for vector baryon interaction and in particular the resonances which appear as composite states, dynamically generated from the interaction of vector mesons with baryons. New developments concerning the mixing of these states with pseudoscalars and baryons are also reported. We include some discussion on the $5/2^+$ $\Delta$ resonances around 2000 MeV, where we suggest that the $\Delta(2000)5/2^+$ resonance, which comes in the PDG from averaging a set of resonances appearing around 1700 MeV and another one around 2200 MeV, corresponds indeed to two distinct resonances. We also report on a hidden charm baryon state around 4400 MeV coming from the interaction of vector mesons and baryons with charm, and how this state has some repercussion in the $J/\psi$ suppression in nuclei. The interaction of $K^*$ in nuclei is also reported and suggestions are made to measure by means of the transparency ratio the huge width in the medium that the theoretical calculations predict. The formalism is extended to $J/\psi$ interaction with nuclei and the transparency ratio for $J/\psi$ photoproduction in nuclei is studied and shown to be a good tool to find possible baryon states which couple to $J/\psi N$.
167214375
Dynamically generated resonances in two meson-one baryon systems
We study the systems of two mesons and one baryon with total strangeness S = −1 (πKN , ππΣ, etc.) by solving Faddeev equations in the coupled channel approach. The calculations have been carried out for L = 0, leading to total spin parity 1/2 for the three body system. The study resulted into dynamical generation of many low-lying Σ and Λ resonances which can be associated to those in the Particle Data Book.
22302838
Limits to the Fixed Center Approximation to Faddeev equations: the case of the $\phi(2170)$
The fixed center approximation to the Faddeev equations has been used lately with success in the study of bound systems of three hadrons. It is also important to set the limits of the approach in those problems to prevent proliferation of inaccurate predictions. In this paper, we study the case of the {phi}(2170), which has been described by means of Faddeev equations as a resonant state of {phi} and KK, and show the problems derived from the use of the fixed center approximation in its study. At the same time, we also expose the limitations of an alternative approach recently proposed.
118423575
Characterisation of NEXT-DEMO using xenon K$_{\alpha}$ X-rays
The NEXT experiment aims to observe the neutrinoless double beta decay of $^{136}$Xe in a high pressure gas TPC using electroluminescence (EL) to amplify the signal from ionization. Understanding the response of the detector is imperative in achieving a consistent and well understood energy measurement. The abundance of xenon k-shell x-ray emission during data taking has been identified as a multitool for the characterisation of the fundamental parameters of the gas as well as the equalisation of the response of the detector. The NEXT-DEMO prototype is a ~1.5 kg volume TPC filled with natural xenon. It employs an array of 19 PMTs as an energy plane and of 256 SiPMs as a tracking plane with the TPC light tube and SiPM surfaces being coated with tetraphenyl butadiene (TPB) which acts as a wavelength shifter for the VUV scintillation light produced by xenon. This paper presents the measurement of the properties of the drift of electrons in the TPC, the effects of the EL production region, and the extraction of position dependent correction constants using K$_{\alpha}$ X-ray deposits. These constants were used to equalise the response of the detector to deposits left by gammas from $^{22}$Na.