14921407
Splitting of the P states in heavy quarkonium systems and the nature of the spin-dependent potential.
We consider the behavior of the splittings between the L = 1 states in heavy quarkonium systems. With standard assumptions, the ratio of mass splittings, R/sub chi/ = (M/sub 2/-M/sub 1/)/(M/sub 1/-M/sub 0/) is shown to grow slowly as we go from the lowest P states to their radial excitations, a behavior which is in accord with other theoretical calculations and is consistent with experiment. This behavior is the opposite of what is expected from a naive argument which we present. We show why the naive argument fails and how the phenomenological division of the potential into components which correspond to the exchange of a Lorentz scalar and vector can be made so as to obtain other behaviors.
125396434
TOP DECAYS WHEN m (t) approximates M (W) + m (b)
125631838
ALGEBRAIC PROPERTIES OF ELECTROMAGNETIC AND WEAK CURRENTS AND THEIR REPRESENTATION ON HADRON STATES
14177217
The physics of heavy flavors
Various aspects of the physics of heavy flavors and of CP violation are reviewed. 102 refs., 21 figs.
119841878
CP violation in K decays
As in the case for much of contemporary research in high energy physics, the area of CP (the product of charge conjugation and parity) violation in K decays is to be seen in the context of a much broader effort of looking for physics beyond the Standard Model. One of the specific types of such physics is represented by the possibility of a fourth family, as exemplified by the title and main focus of this conference. From the broader perspective of looking for new physics of any kind, there are two principal avenues:
120213968
Symmetry Predictions from Sum Rules without Saturation
The application of sum rules derived from current commutation relations to give $\mathrm{SU}(6)$-like results is developed without the assumption of saturation. We first derive a consistency condition by comparing sum rules, and then study the sum rules for $\frac{1}{g_{A}^{}{}_{}{}^{2}}$ and the isovector charge radii, replacing the assumption of saturation with a simple dynamical model for the remaining continuuum contribution. This results in several $\mathrm{SU}(6)$-like predictions which contain important correction factors to the results previously derived assuming saturation. We have also re-examined the experimental data for the sum rule for $\frac{{〈r_{N}^{}{}_{}{}^{2}〉}^{V}}{6}$, and find that it converges below 1 GeV like the sum rule for $\frac{1}{g_{A}^{}{}_{}{}^{2}}$ when account is taken of the contribution to the sum rule of the large resonant ${M}_{1+}$ and nonresonant ${\mathrm{E}}_{0+}$ multipoles in pion photoproduction, and of the ${N}^{**}(1520)$.
40974223
Giant dipole resonances built on isobaric analog states in pion double charge exchange.
Giant resonances were observed in (..pi../sup +/,..pi../sup -/) double charge exchange (at T/sub ..pi../ = 292 MeV) on /sup 56/Fe, /sup 80/Se, and /sup 208/Pb at excitation energies of 28.5, 34.6, and 43.6 MeV, respectively. An angular distribution for /sup 56/Fe was measured and observed to have a dipole shape. The variation of excitation energy above the double isobaric analog state is consistent with an A/sup -1/3/ dependence, as expected for giant dipole resonances built on the isobaric analog states. The /sup 56/Fe angular distribution agrees well with a coupled-channels impulse-approximation calculation in which sequential single charge exchange through the isobaric analog to the giant dipole resonance is evaluated.
30808745
Perturbative QCD effects observed in 490 GeV deep-inelastic muon scattering.
Results on forward charged hadrons in 490 GeV deep-inelastic muon scattering are presented. The transverse momenta, azimuthal asymmetry, and energy flow of events with four or more forward charged hadrons are studied. The range of the invariant hadronic mass squared 300[lt][ital W][sup 2][lt]900 GeV[sup 2]/[ital c][sup 4] extends higher than previous deep-inelastic muon scattering experiments. Data are compared to the predictions of the Lund Monte Carlo model with perturbative QCD simulated by matrix elements, parton showers, and color dipole radiation. All of the QCD-based models are consistent with the data while a model without QCD processes is not. Correlations with the multiplicity-independent event variable [Pi][congruent][summation][vert bar][ital p][sub [ital T]][vert bar] are studied. The relationship between the azimuthal asymmetry and transverse momentum of forward hadrons is also presented. The data are most consistent with intrinsic parton transverse momentum squared [ital k][sub [ital T]][sup 2] of 0.25 GeV[sup 2]/[ital c][sup 2].
40392372
Sequential contribution to nonanalog pion double charge exchange in the Delta 33 resonance region.
In double charge exchange leading to residual nonanalog 0[sup +] ground states, we examine the relative contribution of sequential charge exchange and delta-nucleon charge exchange. We conclude that the data cannot be quantitatively understood in terms of these two reaction mechanisms.
38995408
Pion double charge exchange on T=2 nuclei in the Delta 3/2,3/2 resonance region.
We present cross sections for the reactions {sup 44}Ca,{sup 56}Fe({pi}{sup +},{pi}{sup {minus}}) leading to the residual ground states and double-isobaric-analog states (DIAS) for incident pion energies from 100 to 300 MeV. Data include both angular distributions and 5{degree} excitation functions. Ground-state cross sections were also obtained from the {sup 12}C and {sup 16}O contaminants in the {sup 44}Ca target. The DIAS data are compared to known systematics and to theoretical predictions. Some features of the data are reproduced by the theoretical predictions, but major discrepancies exist.
6727190
Measurement of tensor polarization in elastic electron-deuteron scattering at large momentum transfer
Tensor polarization observables ( t(20), t(21), and t(22)) have been measured in elastic electron-deuteron scattering for six values of momentum transfer between 0.66 and 1.7 (GeV/c)(2). The experiment was performed at the Jefferson Laboratory in Hall C using the electron High Momentum Spectrometer, a specially designed deuteron magnetic channel and the recoil deuteron polarimeter POLDER. The new data determine to much larger Q2 the deuteron charge form factors G(C) and G(Q). They are in good agreement with relativistic calculations and disagree with perturbative QCD predictions.