11 research outputs found

    A Canonical Ds(2317)?

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    It is shown that quark mass dependence induced by one loop corrections to the Breit-Fermi spin-dependent one gluon exchange potential permit an accurate determination of heavy-light meson masses. Thus the Ds(2317)D_s(2317) is a canonical csˉc\bar s meson in this scenario. The multiplet splitting relationship of chiral doublet models, M(1+)−M(1−)=M(0+)−M(0−)M(1^+)-M(1^-) = M(0^+) -M(0^-), holds to good accuracy in the DD and DsD_s systems, but is accidental. Radiative transitions and bottom flavoured meson masses are discussed.Comment: 7 pages, 6 figures. References improve

    Study of meson properties in quark models

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    The main motivation is to investigate meson properties in the quark model to understand the model applicability and generate possible improvements. Certain modifications to the model are suggested which have been inspired by fundamental QCD properties (such as running coupling or spin dependence of strong interactions). These modifications expand the limits of applicability of the constituent quark model and illustrate its weaknesses and strengths. The meson properties studied include meson spectra, decay constants, electromagnetic and electroweak form-factors and radiative transitions. The results are compared to the experimental data, lattice gauge theory calculations and other approaches

    Hybrid Meson Potentials and the Gluonic van der Waals Force

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    The chromoelectric polarizability of mesons governs the strength of the gluonic van der Waals force and therefore of non-quark-exchange processes in hadronic physics. We compute the polarizability of heavy mesons with the aid of lattice gauge theory and the Born--Oppenheimer adiabatic expansion. We find that the operator product expansion breaks down at surprisingly large quarks masses due to nonperturbative gluodynamics and that previous conclusions concerning J/ψJ/\psi--nuclear matter interactions and J/ψJ/\psi dissociation in the quark-gluon plasma must be substantially modified.Comment: 5 pages, RevTex, 2 ps figures. Version to appear in Phys. Lett.

    Canonical Interpretation of the D_{sJ}(2860) and D_{sJ}(2690)

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    The spectrum and decay properties of radially excited DsD_s states are examined in a new model. Good agreement is obtained with the properties of two recently announced DsD_s mesons identified as Ds0(2860)=csˉ(2P)D_{s0}(2860) = c\bar{s}(2P) and Ds∗(2690)=csˉD^*_{s}(2690) = c\bar{s} as a possible mixture of (2S;3S1)(2S;{}^3S_1) and (1D;3D1)(1D;{}^3D_1). Searching for these mesons in B decays is advocated due to large predicted branching ratios.Comment: 6 pages, 2 ps figures, revte

    Dynamic Properties of Charmonium

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    Nonrelativistic quark models of charmonia are tested by comparison of theoretical charmonium decay constants, form factors, and γγ\gamma\gamma widths with experiment and lattice gauge computations. The importance of relativistic effects, a running coupling, and the correct implementation of bound state effects are demonstrated. We describe how an improved model and computational techniques resolve several outstanding issues in previous nonrelativistic quark models such as the use of `correction' factors in quark model form factors, artificial energy prescriptions in decay constant calculations, and ad hoc phase space modifications. We comment on the small experimental value of fψ′′f_{\psi''} and the D-wave component of the J/ψJ/\psi. Decay constants and γγ\gamma\gamma widths for bottomonium are also presented.Comment: 22 pages, 22 ps figures (table entries corrected, text modified

    Uplift of Ionospheric Oxygen Ions During Extreme Magnetic Storms

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    Research reported earlier in literature was conducted relating to estimation of the ionospheric electrical field, which may have occurred during the September 1859 Carrington geomagnetic storm event, with regard to modern-day consequences. In this research, the NRL SAMI2 ionospheric code has been modified and applied the estimated electric field to the dayside ionosphere. The modeling was done at 15-minute time increments to track the general ionospheric changes. Although it has been known that magnetospheric electric fields get down into the ionosphere, it has been only in the last ten years that scientists have discovered that intense magnetic storm electric fields do also. On the dayside, these dawn-to-dusk directed electric fields lift the plasma (electrons and ions) up to higher altitudes and latitudes. As plasma is removed from lower altitudes, solar UV creates new plasma, so the total plasma in the ionosphere is increased several-fold. Thus, this complex process creates super-dense plasmas at high altitudes (from 700 to 1,000 km and higher)

    Extreme changes in the dayside ionosphere during a Carrington-type magnetic storm

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    It is shown that during the 30 October 2003 superstorm, dayside O+ ions were uplifted to DMSP altitudes (~850 km). Peak densities were ~9 × 105 cm−3 during the magnetic storm main phase (peak Dst = −390 nT). By comparison the 1–2 September 1859 Carrington magnetic storm (peak Dst estimated at −1760 nT) was considerably stronger. We investigate the impact of this storm on the low- to mid-latitude ionosphere using a modified version of the NRL SAMI2 ionospheric code. It is found that the equatorial region (LAT = 0° ± 15°) is swept free of plasma within 15 min (or less) of storm onset. The plasma is swept to higher altitudes and higher latitudes due to E × B convection associated with the prompt penetration electric field. Equatorial Ionization Anomaly (EIA) O+ density enhancements are found to be located within the broad range of latitudes ~ ± (25°–40°) at ~500–900 km altitudes. Densities within these peaks are ~6 × 106 oxygen ions-cm−3 at ~700 km altitude, approximately +600% quiet time values. The oxygen ions at the top portions (850–1000 km) of uplifted EIAs will cause strong low-altitude satellite drag. Calculations are currently being performed on possible uplift of oxygen neutrals by ion-neutral coupling to understand if there might be further significant satellite drag forces present

    Extreme changes in the dayside ionosphere during a Carrington-type magnetic storm

    No full text
    It is shown that during the 30 October 2003 superstorm, dayside O+ ions were uplifted to DMSP altitudes (~850 km). Peak densities were ~9 × 105 cm−3 during the magnetic storm main phase (peak Dst = −390 nT). By comparison the 1–2 September 1859 Carrington magnetic storm (peak Dst estimated at −1760 nT) was considerably stronger. We investigate the impact of this storm on the low- to mid-latitude ionosphere using a modified version of the NRL SAMI2 ionospheric code. It is found that the equatorial region (LAT = 0° ± 15°) is swept free of plasma within 15 min (or less) of storm onset. The plasma is swept to higher altitudes and higher latitudes due to E × B convection associated with the prompt penetration electric field. Equatorial Ionization Anomaly (EIA) O+ density enhancements are found to be located within the broad range of latitudes ~ ± (25°–40°) at ~500–900 km altitudes. Densities within these peaks are ~6 × 106 oxygen ions-cm−3 at ~700 km altitude, approximately +600% quiet time values. The oxygen ions at the top portions (850–1000 km) of uplifted EIAs will cause strong low-altitude satellite drag. Calculations are currently being performed on possible uplift of oxygen neutrals by ion-neutral coupling to understand if there might be further significant satellite drag forces present
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