8,916 research outputs found

    On three-body B decays to charm

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    I briefly describe the use of the three-body decay modes B0D()D()0K+B^0 \to D^{(*)-} D^{(*)0} K^+ to investigate open issues in charmed meson spectroscopy, and of the time dependent B0(B0ˉ)(t)DD+π0B^0 (\bar {B^0}) (t) \to D^{-} D^{+} \pi^0 transitions for a measurement of cos(2β)\cos (2 \beta).Comment: LaTeX, 4 pages, 4 figs. Talk at 5th International Conference on Hyperons, Charm and Beauty Hadrons (BEACH 2002), Vancouver, Canada, 25-29 Jun 200

    B decays to excited charm mesons

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    We review several aspects of the phenomenology of P-wave qˉQ\bar q Q mesons: mass splittings, effective strong couplings and leptonic constants. We also describe a QCD sum rule determination to order αs\alpha_s of the form factor τ1/2(y)\tau_{1/2}(y) governing the semileptonic BB decays to the charm doublet with JP=(01/2+,11/2+)J^P=(0^+_{1/2},1^+_{1/2}).Comment: LaTex, 3 pages, 1 figure. Talk given at 3rd International Conference on Hyperons, Charm and Beauty Hadrons, Genoa, Italy, 30 Jun - 3 Jul 199

    The pion and proton mass in finite volume

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    We calculate the finite volume effects for the pion and nucleon mass. For the pion mass we present the results of a full two-loop calculation in chiral perturbation theory. The outcome shows that the resummed version of the Luscher formula we presented in an earlier work does indeed give an excellent approximation to the two-loop result. In view of this result we apply the same resummed formula to the nucleon mass. In the nucleon sector the extension of the chiral expansion to higher quark masses appears to be more problematic and it is therefore more difficult to make reliable predictions for the size of the finite volume effects. We present some preliminary numerical estimates.Comment: 10 pages, 3 figures, Talk given at the Workshop on Computational Hadron Physics, Cyprus, September 14-17, 200

    Anomalous AVVAV^*V vertex in the soft-wall holographic model of QCD

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    We discuss the vertex function of two vector and one axial-vector operators in the soft-wall holographic model of QCD. When one of the two vector currents represents an on-shell soft photon, such a vertex is described by two structure functions wLw_L and wTw_T, which are usually calculated through triangular loop diagrams. We evaluate these functions in the soft-wall model of holographic QCD (HQCD) and compare the outcome to the QCD findings.Comment: 4 pages, contribution to conference "QCD 12", 16th International Conference in Quantum ChromoDynamics, 2nd-6th july 2012 (Montpellier - France

    Finite volume effects for the pion mass at two loops

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    We evaluate the pion mass in finite volume to two loops within Chiral Perturbation Theory. The results are compared with a recently proposed extension of the asymptotic formula of Luscher. We find that contributions, which were neglected in the latter, are numerically very small at the two-loop level and conclude that for Mpi*L>2, L>2fm the finite volume effects in the meson sector are analytically well under control.Comment: 26 pages, 6 figure

    pi pi scattering, pion form factors and chiral perturbation theory

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    I discuss recent progress in our understanding of the pi pi scattering amplitude at low energy thanks to the combined use of chiral perturbation theory and dispersion relations. I also comment on the criticism raised by Pelaez and Yndurain on this work.Comment: 10 pages, 5 figures. Invited talk at the "Quark Confinement and the Hadron Spectrum" VI Conference, Villasimius, Sardinia, Italy, 21-25 September 200

    Chemical Composition of Airborne PM10 Particles from the Salton Sea Playa: Development and Severity of Asthma in Children under 14 in Imperial County

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    Chemical Composition of Airborne PM10 Particles from the Salton Sea Playa: Development and Severity of Asthma in Children under 14 in Imperial County Maggie Colangelo, Depts. of Communication Arts and Environmental Studies, with Prof. Mary Boyes, VCU Honors College I was prompted to begin this paper after reading about a water transfer agreement which will significantly reduce the water levels of the Salton Sea beginning in January 2018. Concerns over the impact this change would have on local air quality and how air quality changes would affect respiratory health, particularly in children were present in the community. I chose to investigate the validity of these concerns. The recession of the Salton Sea will expose large areas of playa, or lakebed, that has been significantly polluted by the agricultural runoff that feeds the Salton Sea. In order to determine the impact this change may have on the air quality of nearby Imperial Valley and what effect airborne pollutants could have on local respiratory health, I studied journals concerning the predicted levels of dust from the exposed playa. Another important aspect of the dust emitted from the playa is the particle mass PM10, which several journals connected to a decrease in childhood respiratory health. I also explored journals which connected persistent organic pollutants which are commonly used in agriculture to respiratory distress and the development of asthma. I focused on journals which studied the levels of the same pollutants in the Salton Sea sediment as well. From my research, I found that the composition, as well as the particle mass of the dust emitted by Salton Sea playa will have a significant negative impact on the respiratory health and development of asthma in Imperial Valley children. Furthermore, the levels of dust emitted by the Salton Sea are expected to increase dramatically as the sea recedes. Continued research and studies should be conducted on the exact composition of airborne pollutants produced by the sea, and their specific impact on childhood respiratory health and asthma development.https://scholarscompass.vcu.edu/uresposters/1294/thumbnail.jp

    Radiative transitions of DsJ(2317)D^*_{sJ}(2317) and DsJ(2460)D_{sJ}(2460)

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    We study radiative decays of DsJ(2317)D^*_{sJ}(2317) and DsJ(2460)D_{sJ}(2460) using light-cone QCD sum rules. In particular, we consider the decay modes DsJ(2317)DsγD^*_{sJ}(2317)\to D_s^* \gamma and DsJ(2460)Ds()γ,DsJ(2317)γD_{sJ}(2460)\to D_s^{(*)} \gamma, D^*_{sJ}(2317) \gamma and evaluate the hadronic parameters in the transition amplitudes analyzing correlation functions of scalar, pseudoscalar, vector and axial-vector quark currents. In the case of DsJ(2317)DsγD^*_{sJ}(2317)\to D_s^* \gamma we also consider determinations based on two different correlation functions in HQET. The decay widths turn out to be different than previous estimates obtained by other methods; the results favour the interpretation of DsJ(2317)D^*_{sJ}(2317) and DsJ(2460)D_{sJ}(2460) as ordinary cˉs\bar c s mesons.Comment: RevTex, 23 pages, 9 eps figure

    Pion loops in quenched Quantum Chromodynamics

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    We calculate the divergences of the generating functional of quenched Chiral Perturbation Theory to one loop for a generic number of flavours. The flavour number dependence of our result enlightens the mechanism of quark loop cancellation in the quenched effective theory for any Green function or S matrix element. We also apply our results to ππ\pi \pi scattering and evaluate the coefficient of the chiral log in the S-wave scattering lengths for the quenched case.Comment: Latex, 10 pages, 1 figur
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