Measurement of P-odd asymmetry of γ-quanta emission in the nuclear reaction 10B(n,α)7Li*→γ+7Li(g.s.)

Search and Measurement of P-Odd Asymmetry in the Emission of Secondary Particles Produced in Reactions of Polarized Thermal and Cold Neutrons with Light Nuclei

“…Yet another theoretical approach consists in expanding the parity-violating NN interaction in powers of the small parameter 1/N c where N c denotes the number of quark colors [12,13]. In this approach, the neutral current coupling constant f π is predicted to be significantly smaller than the charged-current coupling constant as indeed observed experimentally [14][15][16][17][18]. For this reason, it is particularly interesting from the viewpoint of our measurements reported in this paper.…”

“…In subsequent measurements, they were sampled for each single-measurement time interval T and then averaged over the series prior to extracting the normalized asymmetry coefficient. The data are separately processed for each measurement series [26,31].…”

“…of 18 × 18 mm 2 optically connected with the crystals through plexiglass light guides. The two γ-detectors enclosed in duralumin boxes were symmetrically positioned with respect to the beam axis on both sides of the target [31].…”

“…In the first experimental run [31,39], the control of detector operation and data acquisition relied on integrators. The signal-integration time was 0.8 s, and 64 single measurements formed a measurement series.…”

“…Measuring a small P-odd asymmetry requires large event statistics that can be collected only with a very intense particle source. Thus, at least ~10 16 particles should be detected in order to measure an asymmetry on the order of ~10 -8 so as to reduce the statistical uncertainty to an acceptable level. The actually required statistics should be greater than that by a further one or two orders of magnitude as soon as one considers the test runs, measurements of systematic effects, sensitivity losses due to a particular experimental scheme, etc.…”