Radiative vector meson decay

We study the radiative $\rho$, $\omega$ and $\phi$ decay into $\pi^0 \pi^0 \gamma$ and $\pi^0 \eta \gamma$ taking into account mechanisms in which there are two sequential vector-vector-pseudoscalar or axial-vector--vector--pseudoscalar steps followed by the coupling of a vector meson to the photon, considering the final state interaction of the two mesons. Other mechanisms in which two kaons are produced through the same sequential mechanisms or from vector meson decay into two kaons which undergo final state interaction leading to the final pair of pions or $\pi^0 \eta$, are also considered. The results of the parameter free theory, together with the theoretical uncertainties, are compared with the latest experimental results at Frascati and Novosibirsk.Comment: Prepared for the 10th International Symposium on Meson-Nucleon Physics and the Structure of the Nucleo

Chiral Dynamics of scalar mesons: radiative ϕ\phi decay and σ\sigma in the medium through π0π0\pi^0 \pi^0 nuclear photoproduction

In order to assess the relevance of chiral dynamics in the scalar sector we address two recent problems: radiative decay of the $\phi$, for which there are quite recent data from Frascati, and the modification of the $\sigma$ properties in the nuclear medium seen through the $\pi^0 \pi^0$ photoproduction in nuclei.Comment: Talk given at the High Energy Physics Workshop "Scalar Mesons: an Interesting Puzzle for QCD", Utica, New York, May 200

IGR J19294+1816: a new Be-X ray binary revealed through infrared spectroscopy

The aim of this work is to characterize the counterpart to the INTEGRAL High Mass X-ray Binary candidate IGR J19294+1816 so as to establish its true nature. We obtained H band spectra of the selected counterpart acquired with the NICS instrument mounted on the Telescopio Nazionale Galileo (TNG) 3.5-m telescope which represents the first infrared spectrum ever taken of this source. We complement the spectral analysis with infrared photometry from UKIDSS, 2MASS, WISE and NEOWISE databases. We classify the mass donor as a Be star. Subsequently, we compute its distance by properly taking into account the contamination produced by the circumstellar envelope. The findings indicate that IGR J19294+1816 is a transient source with a B1Ve donor at a distance of $d = 11 \pm 1$ kpc, and luminosities of the order of $10^{36-37}$ erg s$^{-1}$, displaying the typical behaviour of a Be X-ray binary.Comment: 8 pages, 6 figures, accepted to be published in MNRA

Recent developments in chiral dynamics of hadrons and hadrons in nuclei

In this talk I present recent developments in the field of hadronic physics and hadrons in the nuclear medium. I review the unitary chiral approach to meson baryon interaction and address the topics of the two dynamically generated $\Lambda(1405)$ resonances, with experiments testing it, the $\Lambda(1520)$ and $\Delta(1700)$ resonances, plus the $\Lambda(1520)$, $\Sigma(1385)$ and $\omega$ in the nuclear medium.Comment: 9 pages, 8 figures, Talk at YKIS06 Kyoto Symposium, Kyoto, december 200

Selected topics on Hadrons in Nuclei

In this talk we report on selected topics on hadrons in nuclei. The first topic is the renormalization of the width of the $\Lambda(1520)$ in a nuclear medium. This is followed by a short update of the situation of the $\omega$ in the medium. The investigation of the properties of $\bar{K}$ in the nuclear medium from the study of the $(K_{flight},p)$ reaction is also addressed, as well as properties of X,Y,Z charmed and hidden charm resonances in a nuclear medium. Finally we address the novel issue of multimeson states.Comment: Talk at the International Nuclear Physics Conference, Vancouver, July 201

Recoverin Regulates Light-dependent Phosphodiesterase Activity in Retinal Rods

The Ca2+-binding protein recoverin may regulate visual transduction in retinal rods and cones, but its functional role and mechanism of action remain controversial. We compared the photoresponses of rods from control mice and from mice in which the recoverin gene was knocked out. Our analysis indicates that Ca2+-recoverin prolongs the dark-adapted flash response and increases the rod's sensitivity to dim steady light. Knockout rods had faster Ca2+ dynamics, indicating that recoverin is a significant Ca2+ buffer in the outer segment, but incorporation of exogenous buffer did not restore wild-type behavior. We infer that Ca2+-recoverin potentiates light-triggered phosphodiesterase activity, probably by effectively prolonging the catalytic activity of photoexcited rhodopsin

AA dependence of the γ\gamma- and pp-induced production of the Λ(1520)\Lambda(1520) from nuclei

Using results of a recent calculation of the $\Lambda(1520)$ in the nuclear medium, which show that the medium width is about five times the free width, we study the A dependence of the $\Lambda(1520)$ production cross section in the reactions $\gamma ~A \to K^+ \Lambda(1520) A^\prime$ and $p~ A \to p~ K^+ \Lambda(1520) A^\prime$. We find a sizable A dependence in the ratio of the nuclear cross sections for heavy nuclei with respect to a light one due to the large value of the $\Lambda(1520)$ width in the medium, showing that devoted experiments, easily within reach in present facilities, can provide good information on that magnitude by measuring the cross sections studied here.Comment: 14 pages, 5 figure