8593515
Phenomenology of an extra neutral gauge boson in electron-positron collisions.
Models with an extra neutral gauge boson (Z') are discussed. We review present limits on the properties of such a Z' which follow from requiring that the Z/sup 0/ mass not be shifted excessively through mixing, from neutral-current experiments, and from the structure of the mass matrix which follows from the Higgs-boson content of particular theories. We then examine what extensions in sensitivity can come from electron-positron annihilation experiments at the Z peak, with emphasis on the importance of cross-section measurements for final states involving lepton or quark pairs, followed by asymmetry measurements with polarized beams. Finally, we consider the additional information provided by asymmetry measurements in electron-positron collisions at energies above the Z.
125631838
ALGEBRAIC PROPERTIES OF ELECTROMAGNETIC AND WEAK CURRENTS AND THEIR REPRESENTATION ON HADRON STATES
125396434
TOP DECAYS WHEN m (t) approximates M (W) + m (b)
14177217
The physics of heavy flavors
Various aspects of the physics of heavy flavors and of CP violation are reviewed. 102 refs., 21 figs.
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 ${N}^{**}(1520)$.
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:
5314277
Neutron and proton matrix elements for transitions in 39K from pion inelastic scattering.
39737388
Measurement of tensor analyzing power in electron-deuteron elastic scattering.
An internal-target technique was used to make the first measurements of the tensor analyzing power {ital T}{sub 20} of electron-deuteron elastic scattering in the four-momentum-transfer range of 2--3 fm{sup {minus}1}. Polarized deuterium atoms were confined within a storage cell in the VEPP-3 electron storage ring in Novosibirsk to achieve a total target thickness of 3{times}10{sup 12} cm{sup {minus}2}, 15 times greater than was previously possible with an atomic-beam target alone. The results for {ital T}{sub 20} are in agreement with reasonable models of the deuteron wave function.
26580602
Nuclear-structure aspects of nonanalog pion double charge exchange.
The sensitivity of pion double charge exchange to nuclear structure in the shell model is examined. We consider the nonanalog ground-state to ground-state (T = 0 to T = 2) transitions on a variety of nuclear targets. The reaction model, which assumes that double charge exchange is driven by a ..pi..+rho-meson--mediated, ..delta../sub 33/-nucleon interaction, reproduces the energy dependence and shape of the empirical cross section for all the (..pi../sup +/,..pi../sup -/) transitions examined. The magnitude of the cross section is particularly sensitive to collectivity in the nuclear wave functions. All parameters of the model, with the exception of the range of the meson-..delta../sub 33/ form factor, are fixed by theoretical arguments. The form factor is then determined by normalizing to the /sup 16/O(..pi../sup +/,..pi../sup -/) /sup 16/ Ne cross section. Predictions are made for a variety of other low-lying 0/sup +/ transitions.
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].
26489055
First measurements of jet production rates in deep-inelastic lepton-proton scattering.
The first measurements of forward multijet rates in deep-inelastic lepton scattering are presented. Data were taken with a 490-GeV muon beam incident on a hydrogen target. The jets were defined using the GADE algorithm. The measured rates are presented as a function of the jet resolution parameter {ital y}{sub cut}, and as a function of the virtual-photon--proton center-of-momentum energy {ital W}, in the range 13{le}{ital W}{le}33 GeV. Comparisons are made to the predictions of the Lund Monte Carlo programs and good agreement is obtained when QCD corrections are included in the model.