[en] It is possible to measure the deep-inelastic spin-dependent structure functions g₁/sup p/(x) and g₁/sup n/(x) for the proton and neutron using internal polarized hydrogen, deuterium, and ³He targets of polarization 50% and thickness 10¹⁴ to 10¹⁵ cm^-2 and the 60 mA longitudinally polarized 30 GeV electron beam in the HERA electron storage ring. The measurement of the deep-inelastic spin-structure of both isospin states of the nucleon at the same kinematics and using the same apparatus allows the Bjorken sum rule to be experimentally checked. In addition, it uniquely constrains the spin distribution of the u and d quarks as a function of x in any model of the nucleon. Possible target and detector configurations are described and an estimate of the accuracy of such a measurement is presented

[en] The G0 experiment will measure the weak neutral current analogs of the proton charge and magnetic form factors in the range of momentum transfer 0.1 ≤Q²≤1 GeV². From these measurements the contributions of the u, d and s quarks to the ordinary charge and magnetic form factors will be determined at the few percent level. This will allow us to better understand the large distance scale structure of the proton insofar as the contributions of the individual flavors to these form factors are essentially unmeasured at present, and especially because the s quarks are exclusively part of the sea. This report will summarize both the plan for the experiment and the apparatus being constructed to perform it. (author)

[en] Measurements of parity-violating electron scattering asymmetries to determine weak neutral currents in nuclei will be effected by the presence of meson exchange currents. Present low momentum transfer calculations, based on a flavor independent framework, show these effects to be small. In general, however, as the momentum transfer increases to values typical of deep-inelastic scattering, fragmentation functions show a clear flavor dependence. It is suggested that a good experimental starting point for understanding the flavor dependence of meson production and exchange currents is the Q² dependence of parity-violating asymmetry in inclusive single pion electroproduction. A CEBAF facility with doubled energy is necessary to approach momentum transfers where this process begins to scale

[en] This paper reports on the Drell-Hearn-Gerasimov (DHG) sum rule which is the integral of the polarized photo-absorption difference cross section over all photon energies. For spin 1/2 targets it is proportional to the anomalous magnetic moment of the particle. Its value for nucleon targets has been determined approximately from N/γ,π amplitudes at about the 25% level of accuracy. It should be possible to determine the value of the integral for photon energies up to about 800 MeV at about the 5% level of uncertainty using inclusive electron scattering at the MIT-Bates Stretcher Ring. The relation of the DHG sum rule to measurements of the Ellis-Jaffe sum rule at asymptotic Q² is also discussed

[en] A new vector form factor of the proton will be measured in a parity-violating electron scattering experiment at MIT-Bates. The experiment will utilize a 500 W LH₂ target and a Cerenkov detector with an acceptance of 2 sr. This new form factor corresponds to the favor singlet current which contributes only to the weak neutral current. In this paper sensitivity of the form factor to vector strange quark currents in the proton is discussed

[en] The proton-proton two-body density in the three-nucleon system is extracted from quasielastic-electron-scattering data. The two-body density is determined in momentum space using the integrated longitudinal response functions and assuming that the nonrelativistic Coulomb sum rule is valid. The range of the measurement is for momenta between 200 and 550 MeV/c. The data are compared to a proton-proton density calculated using Faddeev wave functions. The data and the calculation both show a ''second maximum'' but the data exceed the calculation by about an order of magnitude

[en] The measurement of parity-violation asymmetries in electronic scattering provides a means of extracting the weak neutral current of the target, i.e. that current to which the Z⁰ couples. Because of the relation of the weak and electromagnetic currents, and because of the close relation between the proton and the neutron, such measurements could provide the basis for examining the flavor structure of the nucleon and the nucleus. (orig.)

[en] Measurements of the processes p(π,π), p(ν,ν)/p(nu-bar, nu-bar) and deep-inelastic p(mu, mu') can be interpreted in a manner which requires a significant strange-quark contribution to proton matrix elements. In this paper some implications of strange-quark contributions to proton vector currents and their manifestation in parity-violating electron-scattering experiments are examined. It is found that strange-quark currents of plausible magnitude significantly affect the parity-violating elastic electron scattering from the nucleon in certain kinematic regimes. It is also shown that, while the effects in on-going parity-violating experiments on ⁹Be and ¹²C are small, significant strange-quark contributions might be expected in experiments with nuclear targets at higher momentum transfer

[en] Recoil tritons were detected from the elastic electron scattering reaction ³H(e, t)e'. From these data charge form factors were determined in the range 0.29< or =q/sub μ//sup ts2/< or =1.0 fm^-2. No significant change in the previously reported charge radius for ³H was found

[en] Following up on a suggestion that decay to a dark matter fermion might explain the 4*σ discrepancy in the neutron lifetime, we consider the implications of such a fermion on neutron star structure. We find that including it reduces the maximum neutron star mass to well below the observed masses. In order to recover stars with the observed masses, the (repulsive) self-interactions of the dark fermion would have to be stronger than those of the nucleon-nucleon interaction. (author)