178 research outputs found

    A new interpretation for the Ds2(2573)D^*_{s2}(2573) and the prediction of novel exotic charmed mesons

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    In this manuscript we study the vector - vector interaction within the hidden gauge formalism in a coupled channel unitary approach. In the sector C=1,S=1,J=2C=1,S=1,J=2 we get a pole in the T-matrix around 25722572 MeV that we identify with the Ds2(2573)D^*_{s2}(2573), coupling strongly to the DKD^*K^*(DsϕD^*_s\phi(ω\omega)) channels. In addition we obtain resonances in other exotic sectors which have not been studied before such as C=1,S=1C=1,S=-1, C=2,S=0C=2,S=0 and C=2,S=1C=2,S=1. This 'flavor-exotic' states are interpreted as DKˉD^*\bar{K^*}, DDD^*D^* and DsDD^*_sD^* molecular states but have not been observed yet. In total we obtain nine states with different spin, isospin, charm and strangeness of non C=0,S=0C=0,S=0 and C=1,S=0C=1,S=0 character, which have been reported before

    Two-photon and one photon-one vector meson decay widths of the f0(1370)f_0(1370), f2(1270)f_2(1270), f0(1710)f_0(1710), f2(1525)f'_2(1525), and K2(1430)K^*_2(1430)

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    We calculate the radiative decay widths, two-photon (γγ\gamma\gamma) and one photon-one vector meson (VγV\gamma), of the dynamically generated resonances from vector meson-vector meson interaction in a unitary approach based on the hidden-gauge Lagrangians. In the present paper we consider the following dynamically generated resonances: f0(1370)f_0(1370), f0(1710)f_0(1710), f2(1270)f_2(1270), f2(1525)f_2'(1525), K2(1430)K^*_2(1430), two strangeness=0 and isospin=1 states, and two strangeness=1 and isospin=1/2 states. For the f0(1370)f_0(1370) and f2(1270)f_2(1270) we reproduce the previous results for the two-photon decay widths and further calculate their one photon-one vector decay widths. For the f0(1710)f_0(1710) and f2(1525)f_2'(1525) the calculated two-photon decay widths are found to be consistent with data. The ρ0γ\rho^0\gamma, ωγ\omega\gamma and ϕγ\phi\gamma decay widths of the f0(1370)f_0(1370), f2(1270)f_2(1270), f0(1710)f_0(1710), f2(1525)f'_2(1525) are compared with the results predicted by other approaches. The K+γK^{*+}\gamma and K0γK^{*0}\gamma decay rates of the K2(1430)K^*_2(1430) are also calculated and compared with the results obtained in the framework of the covariant oscillator quark model. The results for the two states with strangeness=0, isospin=1 and two states with strangeness=1, isospin=1/2 are predictions that need to be tested by future experiments.Comment: More discussions about the relation between qqbar states and dynamically generated states; version published in PRD

    Charmed baryon Sigmac(2800) as a ND hadronic molecule

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    The isotriplet Sigmac(2800) baryon with possible quantum numbers J(P) = 1/2(+), 1/2(-) or 3/2(+), 3/2(-) is considered as a hadronic molecule composed of a nucleon and a D meson. We determine the strong two-body decay widths Sigmac to Lambdac + pi which are shown to be consistent with current data for the J(P) = 1/2(+) and J(P) = 3/2(-) assignments.Comment: 8 pages, 2 figure

    The X(3872) and other X,Y,Z Resonances as Hidden Charm Meson-Meson Molecules

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    We report on some ideas concerning the nature of the X(3872) resonance and the need for approximately equal charged and neutral components of DDˉ+ccD \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.Comment: Presented at the Charm2010 Workshop, Beijing, Oct. 201

    The f0(1370)f_0(1370), f0(1710)f_0(1710), f2(1270)f_2(1270), f2(1525)f_2'(1525), and K2(1430)K_2^*(1430) as dynamically generated states from vector meson - vector meson interaction

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    We report on some recent developments in understanding the nature of the low-lying mesonic resonances f0(1370)f_0(1370), f0(1710)f_0(1710), f2(1270)f_2(1270), f2(1525)f_2'(1525), and K2(1430)K_2^*(1430). In particular we show that these five resonances can be dynamically generated from vector meson--vector meson interaction in a coupled-channel unitary approach, which utilizes the phenomenologically very successful hidden-gauge Lagrangians to produce the interaction kernel between two vector mesons, which is then unitarized by the Bethe-Salpeter-equation method. The data on the strong decay branching ratios, total decay widths, and radiative decay widths of these five states, and on related J/ψJ/\psi decay processes can all be well described by such an approach. We also make predictions, compare them with the results of earlier studies, and highlight observables that if measured can be used to distinguish different pictures of these resonances.Comment: 9 pages; Invited talk at workshop CHIRAL'10, Valencia (Spain), June 21-24, 201

    Strong and radiative decays of the scalars f0(980) and a0(980) in a hadronic molecule approach

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    We analyze the electromagnetic and strong decay properties of the light scalars a0(980) and f0(980) within a hadronic molecule interpretation. Both scalars are discussed within a covariant and gauge invariant model which also allows for finite size effects due to their spatially extended structure in the K Kbar-bound state picture. Allowing for f0-a0 mixing we also study its influence on the radiative decays f0/a0 to gamma gamma, f0/a0 to gamma omega, and f0/a0 to gamma rho as well as the phi production of the f0 and a0. Furthermore, we apply our formalism to describe the strong f0 to pi pi and a0 to pi eta decay properties.Comment: 16 pages, 6 figures, typos corrected, accepted for publication in Phys. Rev.

    A dynamical model for longitudinal wave functions in light-front holographic QCD

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    We construct a Schrodinger-like equation for the longitudinal wave function of a meson in the valence qq-bar sector, based on the 't Hooft model for large-N two-dimensional QCD, and combine this with the usual transverse equation from light-front holographic QCD, to obtain a model for mesons with massive quarks. The computed wave functions are compared with the wave function ansatz of Brodsky and De Teramond and used to compute decay constants and parton distribution functions. The basis functions used to solve the longitudinal equation may be useful for more general calculations of meson states in QCD.Comment: 12 pages, 2 figures, RevTeX 4.1; expanded discussion, with calculation details moved to appendice

    Water first aid is beneficial in humans post-burn: evidence from a bi-national cohort study

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    Introduction: Reported first aid application, frequency and practices around the world vary greatly. Based primarily on animal and observational studies, first aid after a burn injury is considered to be integral in reducing scar and infection, and the need for surgery. The current recommendation for optimum first aid after burn is water cooling for 20 minutes within three hours. However, compliance with this guideline is reported as poor to moderate at best and evidence exists to suggest that overcooling can be detrimental. This prospective cohort study of a binational burn patient registry examined data collected between 2009 and 2012. The aim of the study was to quantify the magnitude of effects of water cooling first aid after burn on indicators of burn severity in a large human cohort. Method: The data for the analysis was provided by the Burn Registry of Australia and New Zealand (BRANZ). The application of first aid cooling prior to admission to a dedicated burn service, was analysed for its influence on four outcomes related to injury severity. The patient related outcomes were whether graft surgery occurred, and death while the health system (cost) outcomes included total hospital length of stay and admission to ICU. Robust regression analysis using bootstrapped estimation adjusted using a propensity score was used to control for confounding and to estimate the strength of association with first aid. Dose-response relationships were examined to determine associations with duration of first aid. The influence of covariates on the impact of first aid was assessed. Results: Cooling was provided before Burn Centre admission for 68% of patients, with at least twenty minutes duration for 46%. The results indicated a reduction in burn injury severity associated with first aid. Patients probability for graft surgery fell by 0.070 from 0.537 (13% reduction) (p = 0.014). The probability for ICU admission fell by 0.084 from 0.175 (48% reduction) (p (p = 0.001). All outcomes except death showed a dose-response relationship with the duration of first aid. The size of burn and age interacted with many of the relationships between first aid and outcome and these are described and discussed. Discussion & Conclusion: This study suggests that there are significant patient and health system benefits from cooling water first aid, particularly if applied for up to 20 minutes. The results of this study estimate the effect size of post-burn first aid and confirm that efforts to promote first aid knowledge are not only warranted, but provide potential cost savings
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