Meson resonances in the open and hidden charm sectors

We briefly expose our model for generating open and hidden charm resonances and present the most interesting results.

Charm and hidden charm scalar mesons in the nuclear medium

We study the renormalization of the properties of low-lying charm and hidden charm scalar mesons in a nuclear medium, concretely of the D-s0(2317) and the theoretical hidden charm state X(3700). We find that for the D-s0(2317), with negligible width at zero density, the width becomes about 100 MeV at normal nuclear-matter density, while in the case of the X(3700) the width becomes as large as 200 MeV. We discuss the origin of this new width and trace it to reactions occurring in the nucleus, while offering a guideline for future experiments testing these changes. We also show how those medium modifications will bring valuable information on the nature of the scalar resonances and the mechan…

The radiative decay of $\psi(3770)$ into the predicted scalar state X(3700)

5 pages, 1 figure.-- ISI article identifier:000267299600009.-- ArXiv pre-print avaible at:http://arxiv.org/abs/0805.0499

Corrigendum: ExGUtils: A Python Package for Statistical Analysis With the ex-Gaussian Probability Density

Charmed hadrons in nuclear medium

5th International Conference on Quarks and Nuclear Physics (QNP09).Inst High Energy Phys Chinese Acad Sci, Beijing, PEOPLES R CHINA, SEP 21-25, 2009

Corrigendum: ExGUtils: A Python Package for Statistical Analysis With the ex-Gaussian Probability Density

The study of reaction times and their underlying cognitive processes is an important field in Psychology. Reaction times are usually modeled through the ex-Gaussian distribution, because it provides a good fit to multiple empirical data. The complexity of this distribution makes the use of computational tools an essential element in the field. Therefore, there is a strong need for efficient and versatile computational tools for the research in this area. In this manuscript we discuss some mathematical details of the ex-Gaussian distribution and apply the ExGUtils package, a set of functions and numerical tools, programmed for python, developed for numerical analysis of data involving the ex…

Couplings in coupled channels versus wave functions: Application to theX(3872)resonance

We perform an analytical study of the scattering matrix and bound states in problems with many physical coupled channels. We establish the relationship of the couplings of the states to the different channels, obtained from the residues of the scattering matrix at the poles, with the wave functions for the different channels. The couplings basically reflect the value of the wave functions around the origin in coordinate space. In the concrete case of the $X(3872)$ resonance, understood as a bound state of ${D}^{0}{\overline{D}}^{*0}$ and ${D}^{+}{D}^{*\ensuremath{-}}$ (and $c.c.$ From now on, when we refer to ${D}^{0}{\overline{D}}^{*0}$ , ${D}^{+}{D}^{*\ensuremath{-}}$, or $D{\overline{D}}…

Odd-parity light baryon resonances

We use a consistent SU(6) extension of the meson-baryon chiral Lagrangian within a coupled channel unitary approach in order to calculate the T-matrix for meson-baryon scattering in s-wave. The building blocks of the scheme are the pion and nucleon octets, the rho nonet and the Delta decuplet. We identify poles in this unitary T-matrix and interpret them as resonances. We study here the non exotic sectors with strangeness S=0,-1,-2,-3 and spin J=1/2, 3/2 and 5/2. Many of the poles generated can be associated with known N, Delta, Sigma, Lambda and Xi resonances with negative parity. We show that most of the low-lying three and four star odd parity baryon resonances with spin 1/2 and 3/2 can …

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.

Molecular interpretation of the XYZ states

We study the vector – vector system including all the possible channels with quantum numbers charm = 0, strangeness = 0 around the energy region of 4000 MeV. New states with hidden charm around 4000MeV have been discovered by the B factories. They are intriguingly close to the D*D¯*${D^*}{ar D^*}$ and Ds*D¯s*$D_s^*ar D_s^*$ thresholds and do not have the properties of the charmonium states.We study the possible formation of D*D¯*${D^*}{ar D^*}$ and Ds*D¯s*$D_s^*ar D_s^*$ bound states in the framework of the Hidden Gauge formalism and discuss some of the models that favor the molecular assumption of some XYZ states: The hidden gauge formalism, Heavy baryon Chiral Perturbation Theory and the …

Isospin breaking effects in the X(3872) resonance

In this paper we study the effects of isospin breaking in the dynamical generation of the X(3872) state. We also calculate the ratio of the branching fractions of the $X$ decaying into $J/\psi$ with two and three pions, which has been measured experimentally to be close to unity. Together with the X(3872), of positive C-parity, we predict the existence of a negative C-parity state and we comment on which decay channel is more promising to observe this state.

Differences Between Young and Old University Students on a Lexical Decision Task: Evidence Through an Ex-Gaussian Approach

This work compared two common variants of a lexical decision task (LDT) through two different analysis procedures: first, the classical ANOVA method, and second, by fitting the data to an ex-Gaussian distribution function. Two groups of participants (old and young university students) had to perform, blocks of go/no-go and yes/no tasks. Reaction times and error rates were much lower in the go/no-go task than in the yes/no task. Changes in the ex-Gaussian parameter related to attention were found with word frequency but not with the type of LDT tasks. These findings suggest that word frequency shows an attentional cost that is independent of age.

Chiral unitary dynamics of hadrons and hadrons in a nuclear medium

4th DAE-BRNS Workshop on Hadron Physics. Aligarh Muslim Univ, Dept Phys, Aligarh, INDIA, FEB 18-23, 2008

THE X(3872) AND OTHER X,Y,Z RESONANCES AS HIDDEN CHARM MESON-MESON MOLECULES

We report on some ideas concerning the nature of the X(3872) resonance and the need for approximately equal charged and neutral components of $D \bar{D}^* +cc$. Then we discuss how some hidden charm states are obtained from the interaction between vector mesons with charm and can be associated to some of the charmonium-like X,Y,Z states. Finally we discuss how the nature of these states could be investigated through different types of radiative decay.

Age slowing down in detection and visual discrimination under varying presentation times

[EN] The reaction time has been described as a measure of perception, decision making, and other cognitive processes. The aim of this work is to examine agerelated changes in executive functions in terms of demand load under varying presentation times. Two tasks were employed where a signal detection and a discrimination task were performed by young and older university students. Furthermore, a characterization of the response time distribution by an exGaussian fit was carried out. The results indicated that the older participants were slower than the younger ones in signal detection and discrimination. Moreover, the differences between both processes for the older participants were higher,…

Radiative decay of the dynamically generated open and hidden charm scalar meson resonancesDs0*(2317)andX(3700)

We present the formalism for the decay of dynamically generated scalar mesons with open- or hidden charm and give results for the decay of ${D}_{s0}^{*}(2317)$ to $\ensuremath{\gamma}{D}_{s}^{*}$ plus that of a hidden charm scalar meson state predicted by the theory around 3700 MeV decaying into $\ensuremath{\gamma}J/\ensuremath{\psi}$.

Charm and Hidden Charm Scalar Resonances in Nuclear Matter

18th Particles and Nuclei International Conference (PANIC08). Eilat, ISRAEL, NOV 09-14, 2008

The small-world of 'Le Petit Prince': Revisiting the word frequency distribution

[EN] Many complex systems are naturally described through graph theory, and different kinds of systems described as networks present certain important characteristics in common. One of these features is the so-called scale-free distribution for its node s connectivity, which means that the degree distribution for the network s nodes follows a power law. Scale-free networks are usually referred to as small-world because the average distance between their nodes do not scale linearly with the size of the network, but logarithmically. Here we present a mathematical analysis on linguistics: the word frequency effect for different translations of the Le Petit Prince in different languages. Compar…

The Effect of Corrective Feedback on Performance in Basic Cognitive Tasks: An Analysis of RT Components

[EN] The current work examines the effect of trial-by-trial feedback about correct and error responding on performance in two basic cognitive tasks: a classic Stroop task (n = 40) and a color-word matching task (n = 30). Standard measures of both RT and accuracy were examined in addition to measures obtained from fitting the ex-Gaussian distributional model to the correct RTs. For both tasks, RTs were faster in blocks of trials with feedback than in blocks without feedback, but this difference was not significant. On the other hand, with respect to the distributional analyses, providing feedback served to significantly reduce the size of the tails of the RT distributions. Such results sugge…

Recent Developments in Chiral Unitary Dynamics of Resonances

In this talk I summarize recent findings made on the description of axial vector mesons as dynamically generated states from the interaction of peseudoscalar mesons and vector mesons, dedicating some attention to the two $K_1(1270)$ states. Then I review the generation of open and hidden charm scalar and axial states. Finally, I present recent results showing that the low lying $1/2^+$ baryon resonances for S=-1 can be obtained as bound states or resonances of two mesons and one baryon in coupled channels dynamics.

Exotic dynamically generated baryons with negative charm quantum number

Following a model based on the SU(8) symmetry that treats heavy pseudoscalars and heavy vector mesons on an equal footing, as required by heavy quark symmetry, we study the interaction of baryons and mesons in coupled channels within an unitary approach that generates dynamically poles in the scattering T-matrix. We concentrate in the exotic channels with negative charm quantum number for which there is the experimental claim of one state.

Couplings in coupled channels versus wave functions: application to the X(3872) resonance

We perform an analytical study of the scattering matrix and bound states in problems with many physical coupled channels. We establish the relationship of the couplings of the states to the different channels, obtained from the residues of the scattering matrix at the poles, with the wave functions for the different channels. The couplings basically reflect the value of the wave functions around the origin in coordinate space. In the concrete case of the X(3872) resonance, understood as a bound state of D-0(D) over bar*(0) and D+D*(-) (and c.c. From now on, when we refer to D-0(D) over bar*(0), D+D*(-), or D (D) over bar* we are actually referring to the combination of these states with the…

Meson and baryon resonances

6 pages, 1 table.-- PACS nrs.: 13.75.Lb, 14.40.Cs, 12.40.Vv, 12.40.Yx.-- Talk at the 2008 International Conference on Particles And Nuclei (PANIC08, Nov 9-14, 2008, Eilat, Israel).

Axial resonances in the open and hidden charm sectors

13 pages, 2 figures.-- PACS nrs.: 11.10.St, 11.80.Gw, 12.39.Hg, 12.39.Fe.-- ISI Article Identifier: 000249271600001.-- ArXiv pre-print available at: http://arxiv.org/abs/0704.2314

Dynamically generated open and hidden charm meson systems

We will study open and hidden charm scalar meson resonances within two different models. The first one is a direct application of a chiral Lagrangian already used to study flavor symmetry breaking in Skyrme models. In another approach to the problem a SU(4) symmetric Lagrangian is built and the symmetry is broken down to SU(3) by identifying currents where heavy mesons are exchanged and suppressing those. Unitarization in couple channels leads to dynamical generation of resonances in both models, in particular a new hidden charm resonance with mass 3.7 GeV is predicted. The small differences between these models and with previous works will be discussed.