V.A. Nazarenko

New measurement of the electric dipole moment of the neutron

Abstract A new experiment on the search for the electric dipole moment of the neutron was carried out using a magnetic resonance set-up with electric field and stored ultracold neutrons. The EDM of the neutron was measured to be +(2.6±4.2±1.6)×10−26 e cm, the first error being RMS or statistical and the second one systematical. An upper limit at the 95% CL is |dn|

A new upper limit on the electric dipole moment of the neutron

Abstract New measurements have reduced the upper limit for the electric dipole moment of the neutron to | d | −25 e cm (90% confidence level).

A new experimental study of the circular polarization of np capture γ-rays

Abstract An installation using a light-water neutron trap in the reactor core as a proton target is described. Results of the main and control measurements are presented which permit one to conclude that the parity-violating circular polarization of the γ-rays from the np → d γ reaction is P γ = (1.8 ± 1.8) × 10 −7 .

A search for the electric dipole moment of the neutron using ultracold neutrons

Abstract The results of measurements of the electric dipole moment (EDM) of the neutron using ultra-cold neutrons (UCN) are presented. A description is given of the source of UCN devised, and of a magnetic resonance spectrometer confining UCN for ≈ 5 s. The use of a double-chamber spectrometer and a system for double analysis of polarization enabled us to eliminate most of the systematic errors possible. The measurements resulted in the EDM d =(4±7.5) × 10 −25 e · cm. From this it is inferred that ¦d¦ −24 e · cm at the confidence level of 90%.

A liquid hydrogen source of ultra-cold neutrons

Abstract A liquid hydrogen source of ultra-cold neutrons (UCN) developed for an experimental search for the electric dipole moment of the neutron is described. The results of an investigation of the yield of UCN from gaseous, liquid, and solid hydrogen as a function of temperature are presented. The UCN counting rate obtained at the output of the 6 × 7 cm 2 neutron guide tube is 5 × 10 4 n/s. This counting rate corresponds to a flux of neutrons whose velocity along the axis of the neutron guide tube is below 7 m/s. Preliminary measurements of the UCN yield from liquid and solid deuterium have been carried out.

Circular polarization of γ-quanta in np→dγ reactions with polarized neutrons

Abstract The circular polarization of the 2.23 MeV γ -quanta in the reaction np→d γ with polarized cold neutrons has been measured to be P γ =(−1.5±0.3)×10 −3 . A high-purity solid parahydrogen target was used. The circular polarization was measured with two magnetic transmission polarimeters, NaI(Tl) crystals with photomultipliers were used as detectors. The result is examined from the point of view of recent theoretical calculations.

Circular polarization of gamma quanta in the radiative capture of polarized thermal neutrons by protons

Abstract An experiment to measure the circular polarization of γ-quanta, P γ , in the reaction of radiative capture of polarized thermal neutrons by protons is described. Solid parahydrogen was employed as a proton target. The circular polarization was found to be P γ = −(2.90 ± 0.87) × 10 −3 which is in agreement with the theoretical estimates of P γ arising from the admixture of the triplet capturing state to the 1 S 0 principal capturing state.