Neutral currents and elastic scattering of neutrinos and antineutrinos on a polarized proton target

The processes of elastic scattering of neutrinos and antineutrinos on a polarized proton target are considered on the basis of the Weinberg-Salam gauge theory. Expressions are found for the differential cross sections, spin asymmetry, and the degree of polarization of recoil protons in the reactions indicated. The formulas obtained are analyzed from the position of the latest experimental data on the Weinberg parameter.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 85–89, December, 1976.In conclusion it gives me pleasure to thank Prof. A. A. Sokolov and N. A. Guliev for their useful discussion and their interest in this paper.     

Flux and spectrum of reactor antineutrinos

In order to perform reactor experiments aimed at studying the nature of the neutrino and measurements in the realms of geo- and astrophysical neutrinos and to meet practical requirements in this field, it is highly desirable to obtain deeper insight into the operation of nuclear reactors as a source of antineutrinos. The fluxes and spectra of neutrinos from a reactor in the on and off modes and from a reservoir intended for storing a spent reactor fuel and situated near the reactor being considered are calculated. Features that are peculiar to the flux and spectrum of reactor antineutrinos and which are of importance for implementing and interpreting experiments, but which were disregarded previously, are analyzed here.     

Disintegration of the deuteron by reactor antineutrinos

Cross sections calculated with a new standard reactor antineutrino spectral function are in good agreement with new experimental data.     

Identifying neutrinos and antineutrinos in neutral-current scattering reactions

We study neutrino-induced nucleon knockout from nuclei. Expressions for the induced polarization are derived within the framework of the independent-nucleon model and the nonrelativistic plane-wave approximation. Large dissimilarities in the nucleon polarization asymmetries are observed between neutrino- and antineutrino-induced processes. These asymmetries represent a potential way to distinguish between neutrinos and antineutrinos in neutral-current neutrino scattering on nuclei. We discuss astrophysical applications of these polarization asymmetries. Our findings are illustrated for neutrino scattering on 16O and 208P b.     

Neutral current effects in the parity violating nuclear force

The measurements of the ΔI = 1 part of the parity violating nuclear force when combined with information on neutral current couplings from neutrino scattering and pion production experiments allow an estimate of the isoscalar admixture in the neutral current if it has a vector axial-vector structure has been shown.     

Weak and magnetic inelastic scattering of antineutrinos on atomic electrons

Neutrino scattering on electrons is considered as a tool for laboratory searches for the neutrino magnetic moment. Inelastic $\bar \nu _e e^ - $ scattering on electrons bound in the germanium (Z=32) and iodine (Z=53) atoms is studied for antineutrinos generated in a nuclear reactor core and in ⁹⁰Sr-⁹⁰Y and ¹⁴⁷Pm artificial sources. On the basis of the relativistic Hartree-Fock-Dirac model, both the magnetic-and weak-scattering cross sections are calculated for the recoil electron energy range between 1 and 100 keV, where a higher sensitivity to the neutrino magnetic moment could be achieved. Particular attention is paid to an approximate procedure that allows us to take into account the effects of atomic binding on the inelastic-scattering spectra in a simple way.     

Study of inclusive neutral current interactions of neutrinos and antineutrinos

We report on results from a study of hadron-energy distributions for ν and $\text{ν}$ inclusive neutral current interactions. There is no significant variation of the neutral to charged current total cross-section ratios R_ν and $\text{R}\text{ν}$ with neutrino energy. The space-time structure of neutral currents is dominated by V?A, with a significant admixture of V+A. The Weinberg-Salam model is in agreement with all data if sin²θ_w=0.24±0.02.     

Inelastic scattering of tritium-source antineutrinos on electrons of germanium atoms

Processes of the inelastic magnetic and weak scattering of tritium-beta-source antineutrinos on the bound electrons of a germanium atom are considered. The results obtained by calculating the spectra and cross sections are presented for the energy-transfer range between 10 eV and 18 keV.     

Experimental spectrum of reactor antineutrinos and spectra of main fissile isotopes

Within the period between the years 1988 and 1990, the spectrum of positrons from the inverse-beta-decay reaction on a proton was measured at the Rovno atomic power plant in the course of experiments conducted there. The measured spectrum has the vastest statistics in relation to other neutrino experiments at nuclear reactors and the lowest threshold for positron detection. An experimental reactor-antineutrino spectrum was obtained on the basis of this positron spectrum and was recommended as a reference spectrum. The spectra of individual fissile isotopes were singled out from the measured antineutrino spectrum. These spectra can be used to analyze neutrino experiments performed at nuclear reactors for various compositions of the fuel in the reactor core.     

Meson exchange and isobar current effects in nuclear photon scattering

Explicit expressions of meson exchange and isobar current contributions to the nuclear two-photon amplitude are derived in the non-relativistic limit. In connection with this amplitude the requirement of gauge invariance on the photon scattering amplitude and on the nuclear electromagnetic interaction operator is discussed in detail.     

Deep inelastic scattering of neutrinos and antineutrinos by a polarized proton in the quark-parton model

Deep inelastic scattering of neutrinos and antineutrinos by polarized protons is considered in the quark-parton model. For processes with charged currents, a connection is obtained between the asymmetry of the differential cross sections corresponding to different spin directions of the target proton and the distribution functions of the polarized partons in the polarized proton (d for neutrinos and u for antineutrinos). It is shown that the presence of an x dependence of the asymmetry parameter corresponds to a difference between the distribution functions of partons with opposite helicity. For processes with neutral currents, relations are obtained between the asymmetry parameters and the constants that determine the helicity structure of the weak neutral quark current.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 4, pp. 41–45, April, 1980.I thank Professor B. K. Kerimov and A. É. Astratyan for a helpful discussion of the work.     

Neutral impurity scattering in semiconductors

Summary Applying the correlation function technique, a temperature-independent mobility μ_n has been obtained and it is shown that this μ_n remains close to the experimental mobility ofn-type Ge around 10 K.     

Mössbauer antineutrinos: Recoilless resonant emission and absorption of electron antineutrinos

Basic questions concerning phononless resonant capture of monoenergetic electron antineutrinos (Mössbauer antineutrinos) emitted in bound-state β-decay in the ³H-³He system are discussed. It is shown that lattice expansion and contraction after the transformation of the nucleus will drastically reduce the probability of phononless transitions and that various solid-state effects will cause large line broadening. As a possible alternative, the rare-earth system ¹⁶³Ho-¹⁶³Dy is favoured. Mössbauer-antineutrino experiments could be used to gain new and deep insights into several basic problems in neutrino physics.     

Neutral currents in elastic neutrino-nucleon scattering

We investigate elastic neutrino (antineutrino)-nucleon scattering in the case where some pieces of neutral currents are related to those which appear in electromagnetism and in weak charge-changing reactions. From Gargamelle preliminary results on elastic reactions we get numerical constraints on the parameters which connect the vector parts of neutral currents with the electromagnetic current. Using inclusive neutral current data we give predictions on elastic cross sections in the case of various models of neutral currents.     

Neutral vector bosons in Bhabha scattering

The colliding-beam experiments ofe ⁺ ande ^?-annihilation scattering mediated by a weakly coupled neutral vector bosonW ⁰ as suggested by various authors are recalculated in more detail. It is shown that the height of the resonance, which is to be expected at the mass-shell energies of W⁰, can be determined exactly by renormalizing the second-order self-energy diagram ofW ⁰. It is further shown, how the special form of the cross-section could serve as a test for the correctness of aV- A ansatz in neutral current interactions.