An analysis of the Lattice QCD spectra for Ds0∗(2317)D^*_{s0}(2317) and Ds1∗(2460)D^*_{s1}(2460)

In this talk I present the results obtained using effective field theories in a finite volume from a reanalysis of lattice data on the $KD^{(*)}$ systems, where bound states of $KD$ and $KD^*$ are found and associated with the states $D^*_{s0}(2317)$ and $D^*_{s1}(2460)$, respectively. We confirm the presence of such states on the lattice data and determine the weight of the $KD$ channel in the wave function of $D^*_{s0}(2317)$ and that of $KD^*$ in the wave function of $D^*_{s1}(2460)$. Our results indicate a large meson-meson component in both cases.Comment: Conference Proceedings, Hadron 2017, Salamanca, Spai

Genus and spot density in the COBE DMR first year anisotropy maps

A statistical analysis of texture on the {\it COBE}-DMR first year sky maps based on the genus and spot number is presented. A generalized $\chi^2$ statistic is defined in terms of ``observable'' quantities: the genus and spot density that would be measured by different cosmic observers. This strategy together with the use of Monte Carlo simulations of the temperature fluctuations, including all the relevant experimental parameters, represent the main difference with previous analyses. Based on the genus analysis we find a strong anticorrelation between the quadrupole amplitude $Q_{rms-PS}$ and the spectral index $n$ of the density fluctuation power spectrum at recombination of the form $Q_{rms-PS}= 22.2 \pm 1.7 - (4.7 \pm 1.3) \times n\ \mu$K for fixed $n$, consistent with previous works. The result obtained based on the spot density is consistent with this $Q_{rms-PS} (n)$ relation. In addition to the previous results we have determined, using Monte Carlo simulations, the minimum uncertainty due to cosmic variance for the determination of the spectral index with the genus analysis. This uncertainty is $\delta n\approx 0.2$.Comment: 5 pages, uuencode file containing text and 1 figure. MNRAS in press

Study of the D∗ρD^*\rho system using QCD sum rules

In this talk I present a study of the $D^* \rho$ system made by using the method of QCD sum rules. Considering isospin and spin projectors, we investigate the different configurations and obtain three $D^*$ mesons with isospin $I=1/2$, spin $S=0$, $1$, $2$ and with masses $2500\pm 67$ MeV, $2523\pm60$ MeV, and $2439\pm119$ MeV, respectively. The last state can be related to $D^*_2(2460)$ (spin 2) listed by the Particle Data Group, while one of the first two might be associated with $D^*(2640)$, whose spin-parity is unknown. In the case of $I=3/2$ we also find evidences of three states with spin 0, 1 and 2, respectively, with masses $2467\pm82$ MeV, $2420\pm128$ MeV, and $2550\pm56$ MeV.Comment: Contribution to the proceedings of the XXXVI Reuni\~ao de Trabalho sobre F\'isica Nuclear no Brasil, Maresias, S\~ao Paulo, Brazi

A study of the KNKN-K∗NK^*N coupled systems

We study the strangeness $+1$ meson-baryon systems to obtain improved $KN$ and $K^*N$ amplitudes and to look for a possible resonance formation by the $KN$-$K^*N$ coupled interaction. We obtain amplitudes for light vector meson-baryon systems by implementing the $s$-, $t$-, $u$- channel diagrams and a contact interaction. The pseudoscalar meson-baryon interactions are obtained by relying on the Weinberg-Tomozawa theorem. The transition amplitudes between the systems consisting of pseudoscalars and vector mesons are calculated by extending the Kroll-Ruderman term for pion photoproduction replacing the photon by a vector meson. We fix the subtraction constants required to calculate the loops by fitting our $KN$ amplitudes to the data available for the isospin 0 and 1 $s$-wave phase shifts. We provide the scattering lengths and the total cross sections for the $KN$ and $K^* N$ systems obtained in our model, which can be useful in future in-medium calculations. Our amplitudes do not correspond to formation of any resonance in none of the isospin and spin configurations.Comment: Published version, sent to avoid confusions recently noticed by author

On the absorption and production cross sections of KK and K∗K^*

We have computed the isospin and spin averaged cross sections of the processes $\pi K^*\to \rho K$ and $\rho K^*\to \pi K$, which are crucial in the determination of the abundances of $K^*$ and $K$ in heavy ion collisions. Improving previous calculations, we have considered several mechanisms which were missing, such as the exchange of axial and vector resonances ($K_1(1270)$, $K^*_2(1430)$, $h_1(1170)$, etc...) and also other processes such as $\pi K^*\to \omega K, \phi K$ and $\omega K^*,\,\phi K^*\to \pi K$. We find that some of these mechanisms give important contributions to the cross section. Our results also suggest that, in a hadron gas, $K^*$ production might be more important than its absorption

X(3872)X(3872) production and absorption in a hot hadron gas

We calculate the time evolution of the $X(3872)$ abundance in the hot hadron gas produced in the late stage of heavy ion collisions. We use effective field Lagrangians to obtain the production and dissociation cross sections of $X(3872)$. In this evaluation we include diagrams involving the anomalous couplings $\pi D^*\bar{D}^*$ and $X \bar{D}^{\ast} D^{\ast}$ and also the couplings of the $X(3872)$ with charged $D$ and $D^*$ mesons. With these new terms the $X(3872)$ interaction cross sections are much larger than those found in previous works. Using these cross sections as input in rate equations, we conclude that during the expansion and cooling of the hadronic gas, the number of $X(3872)$, originally produced at the end of the mixed QGP/hadron gas phase, is reduced by a factor of 4.Comment: 8 pages, 4 figure

Interpreting the peak structures around 1800 MeV in the BES data on J/Ψ→ϕπ+π−J/\Psi \to \phi \pi^+ \pi^-, J/Ψ→γωϕJ/\Psi\to \gamma \omega \phi

In this talk we present an interpretation for the experimental data available on two different processes, namely, $J/\Psi \to \phi \pi^+ \pi^-$, $J/\Psi\to \gamma \omega \phi$, which seem to indicate existence of two new resonances with the same quantum numbers ($J^{\pi c}=0^{++}, I = 0$) and very similar mass (~1800 MeV) but with very different decay properties. However, our studies show that the peak structure found in the $\omega \phi$ invariant mass, in $J/\Psi \to \gamma \omega \phi$, is a manifestation of the well known $f_0(1710)$ while the cross section enhancement found in $J/\Psi \to \phi \pi^+ \pi^-$ is indeed a new $f_0$ resonance with mass near 1800 MeV. We present an explanation for the different decay properties of these two scalar resonances.Comment: Proceedings for the nuclear physics meeting ("XXXVI Reuni\~ao de trabalho sobre f\'isica nuclear no Brasil") held in Maresias during Sept. 1-5. To be published as AIP proceeding

X, Y and Z States

Many new states in the charmonium mass region were recently discovered by BaBar, Belle, CLEO-c, CDF, D0, BESIII, LHCb and CMS Collaborations. We use the QCD Sum Rule approach to study the possible structure of some of these states.Comment: Contribution for the proceedings of the "XII Quark Confinement and the Hadron Spectrum - CONF12" conferenc