Parity nonconservation and stellar collapse
ACCORDING to the current theory, the evolution of sufficiently massive stars leads eventually to gravitational instability and collapse. After thermonuclear burning has stopped, dense stellar cores become unstable and collapse to form neutron stars (pulsars) or black holes. In both cases energy of the order of 0.1 Mc2 is released, mostly in the form of neutrinos and gravitational waves. As the radius of the core decreases, its magnetic field grows (magnetic flux is conserved) and can reach huge values of order 1012–1013 G. Even greater azimuthal fields (∼3 × 1015 G) can be generated by differential rotation of the core1. It will be shown here that neutrino emission in the collapse is asymmetric, as a result of parity nonconservation in weak interactions. Neutrinos and antineutrinos are emitted preferentially in the direction parallel to the local magnetic field of the collapsing core.
Investigating the effect of a magnetic field on beta decay
The effect of an external magnetic field on theβ-decay process of a neutron is analyzed in detail. The spin effects within this process are studied, as is the final mass of the neutrino. Results of computer-based experiments are presented.
Perturbed angular correlation study of a haptenic molecule.
The angular correlation of the 173-247 keV gamma-ray cascade after the electron-capture decay of (111)In is strongly perturbed when the 1-p-nitrophenyl-ethylenediaminetetraacetate chelate of (111)In(8+) is added to a solution containing rabbit antibody to dinitrophenyl groups. The radioactive chelate can be displaced by the addition of dinitrophenyllysine or unlabeled chelate. The average association constant between the antibody and the labeled chelate has been estimated from perturbed angular correlation measurements; this value is compared to the results of equilibrium dialysis. These experiments provide good evidence that information concerning macromolecular behavior can be obtained from perturbed angular correlation experiments that use chemically specific labels.