• The Evolution of Neutral Gas in the Universe

      Turnshek, David; Rao, Sandhya; Monier, Eric; Nestor, Daniel; Quider, Anna; Cambridge University; The College at Brockport; University of Pittsburgh (1/1/2006)
      We give references to some of our work on the properties and evolution of the neutral gas component of the Universe (see reference list). The bulk of the observed neutral gas has been detected by identifying intervening damped Ly? (DLA) quasar absorption-line systems with N(H) > 2 × 1020 atoms cm ?2. We also present some initial results from a program to identify DLA absorbers near redshift z = 0.5 using Hubble Space Telescope ACS prism spectra
    • Note on Recent Measurements of the ?(1S) ???? (1S) and ?(2S) ???? (1S) Branching Ratios

      Radford, Stanley F.; Repko, Wayne W.; Michigan State University; The College at Brockport (1/1/2008)
      Recently published measurements of the branching ratios ?(?(1S) ???_? (1S)) and ?(?(2S) ???_? (1S)) by the CLEO Collaboration are examined in the context of a potential model that includes both relativistic and one-loop QCD corrections to the quark-antiquark interaction. The prediction for the width ? (?(1S) ???_? (1S)) is in excellent agreement with the new data, but the prediction for ? (?(2S) ???_? (1S)) is too small. In an effort to understand this discrepancy, we derive an upper bound on ? (?(2S) ???_? (1S)) and point out its experimental value saturates this bound.
    • Comment on Spin-Dependent Forces in Heavy-Quark Systems

      Gupta, Suraj N.; Radford, Stanley F.; Repko, Wayne W.; Michigan State University; The College at Brockport; Wayne State University (12/1/1985)
      A Comment on the Letter by Y. J. Ng et al., Phys. Rev. Lett. 55, 916 (1985).
    • Potential model calculations and predictions for heavy quarkonium

      Radford, Stanley F.; Repko, Wayne W.; Michigan State University; The College at Brockport and Kavli Institute for Theoretical Physics (4/30/2007)
      We investigate the spectroscopy and decays of the charmonium and upsilon systems in a potential model consisting of a relativistic kinetic energy term, a linear confining term including its scalar and vector relativistic corrections and the complete perturbative one-loop quantum chromodynamic short distance potential. The masses and wave functions of the various states are obtained using a variational technique, which allows us to compare the results for both perturbative and nonperturbative treatments of the potential. As well as comparing the mass spectra, radiative widths and leptonic widths with the available data, we include a discussion of the errors on the parameters contained in the potential, the effect of mixing on the leptonic widths, the Lorentz nature of the confining potential, and the possible cc interpretation of recently discovered charmoniumlike states.
    • Semirelativistic Potential Model for Heavy Quarkonia

      Gupta, Suraj N.; Radford, Stanley F.; Repko, Wayne W.; Michigan State University; The College at Brockport; Wayne State University (7/1/1986)
      The c¯c, b¯b, and t¯t spectra are investigated with the use of a semirelativistic potential model described in an earlier paper. Results for the energy levels, leptonic widths, and E1 transition widths are compared with the experimental data for c¯c, and b¯b, and predicted for t¯t. We also find that the quark-antiquark interaction can best be described by a quasistatic rather than a momentum-dependent potential, and propose a theoretical justification for this surprising conclusion.
    • Potential Model Calculations and Predictions for c¯s quarkonia

      Radford, Stanley F.; Repko, Wayne W.; Saelim, Michael J.; Michigan State University; The College at Brockport; Kavli Institute for Theoretical Physics (8/12/2009)
      We investigate the spectroscopy and decays of the charm-strange quarkonium system in a potential model consisting of a relativistic kinetic energy term, a linear confining term including its scalar and vector relativistic corrections, and the complete perturbative one-loop quantum chromodynamic short distance potential. The unperturbed wave functions of the various states are obtained using a variational technique. These are then used in a perturbative treatment of the potential to fit the mass spectrum of the cs system and calculate the radiative decay widths. Our results compare well with the available data for the spectrum of Ds states. We include a discussion of the effect of mixing and investigation of the Lorentz nature of the confining potential.