International Journal of Modern Physics A

The purpose of this work is to discuss the utility of electron scattering in the study of nuclear properties. After an introduction to the subject, we present a historical overview and details of experimental facilities. The bulk of the paper is focused on the analysis of the nuclear response below the pion production threshold. We place special emphasis on what kind of information electron scattering provides about the nuclear structure of closed-shell nuclei and their neighbors. Selected examples are analyzed throughout the paper.

A five-parameter class of colliding plane gravitational wave solutions is obtained by using the soliton technique of Belinsky and Zakharov, which includes most of the important known solutions. A four-parameter subclass of the solutions can be considered as a noncollinear generalization of the famous Szekeres family of colliding collinear polarization plane gravitational wave solutions. The effect of polarization of colliding plane gravitational waves on the formation and nature of singularities is, in turn, investigated.

In this paper we study the dynamics of one-dimensional multiply connected systems, or networks, and find under what conditions the Hamiltonian is self-adjoint. These conditions give the spectrum, and impose superselection rules in the “non-Abelian” case. We discuss the spectrum and superselection rules for some special cases.

Using Martin’s potential, independently of b- and c-quark flavours, we calculate the mass spectrum of -mesons and widths of electromagnetic transition between them. We obtain the estimates of the production cross-section at e⁺e⁻ colliders, in hadronic and neutrino interactions. A real possibility of observing B_c-mesons at LEP (up to 500 B_c per 10⁶ Z⁰) and at hadron colliders has been pointed out. The importance of observing the annihilation decay channels of B_c-mesons—B_c→τν_τ(Br(B_c→τν_τ)=1.5–2%) and B_c→ϕD_s, DK, etc.—has been emphasized.

We study the symmetry of two-dimensional gravity by choosing a generic gauge. A local action is derived which reduces to either the Liouville action or the Polyakov one by reducing to the conformal or light-cone gauge respectively. The theory is also solved classically. We show that an SL(2, R) covariant gauge can be chosen so that the two-dimensional gravity has a manifest Virasoro and the sl(2, R)-current symmetry discovered by Polyakov. The symmetry algebra of the light-cone gauge is shown to be isomorphic to the Beltrami algebra. By using the contour integration method we construct the BRST charge Q_B corresponding to this algebra following the Fradkin-Vilkovisky procedure and prove that the nilpotence of Q_B requires c=28 and α₀=1. We give a simple interpretation of these conditions.

A detailed analysis is performed so as to reveal the statistical significance of the possible anticorrelation between the solar neutrino flux, measured by the ³⁷Cl experiment, and the sunspot activity. We find that the new data added since 1986 do contribute to improving the significance of the anticorrelation. However, we also observe that the statistical significance depends upon the treatment of errors rather sensitively. Therefore, we conclude that the anticorrelation is not definitively established at the present stage of the experiment. We also point out the possibility of a new type of correlation.

Supersymmetric theories are shown to possess singularities of the renormalon type unless the theories are finite. However, the Landau pole found in λϕ⁴ and QED is replaced by a cut singularity. It is argued that the Wess-Zumino model is trivial.

We calculate in a simple model the reduction in probability for (say) an electron neutrino to rotate to another state in a transverse magnetic field when that field twists in the transverse plane. This may be of relevance to a “second generation” analysis of solar neutrinos. Connection with the Berry phase for this problem is also discussed.