Eugene D. Commins

Weak Interactions of Leptons and Quarks

In recent years, the study of weak interaction and its relationship with the other fundamental interactions of nature has progressed rapidly. Weak interactions of leptons and quarks provides an up-to-date account of this continuing research. The Introduction discusses early models and historical developments in the understanding of the weak force. The authors then give a clear presentation of the modern theoretical basis of weak interactions, going on to discuss recent advances in the field. These include the development of the electroweak gauge theory and the discovery of neutral currents and of a host of new particles-notable among these are the /tau/ lepton and the charmed quark. There is also a chapter devoted entirely to neutrino astrophysics.

Observation of the 6 2P12−7 2P12 M1 transition in atomic thallium vapor☆

The 6 2P12−7 2P12 (292.7 nm) M1 transition in Tl is observed and its matrix element m = 〈7 2P12 |μZ| 6 2P12〉 is measured. Tl vapor is illuminated by a pulsed linearly polarized laser beam (λ = 292.7 nm). Interference between m and the Stark-induced 6 2P12−7 2P12 E1 amplitude in finite electric field E results in circular polarization of 535 nm fluorescence proportional to m/E, which is detected. The result is m = −(2.11 ± 0.30) × 10−5 | eh/2mec| in agreement with theory. The ultimate goal of this research is to detect parity violation in the neutral weak interaction by observation of a helicity dependence in the 6 2P12−7 2P12 absorption when the laser light is circularly polarized.

Berry's geometric phase and motional fields

An experiment is described that provides an example of how Berry’s geometric phase arises from motion of a particle with a magnetic moment in an electric field and an inhomogeneous magnetic field.

Resource Letter ETDSTS‐1: Experimental tests of the discrete space‐time symmetries

This Resource Letter provides a guide to the literature on experimental tests of space‐inversion symmetry or parity (P), charge conjugation symmetry (C), time reversal symmetry (T), and the combined symmetries CP and CPT. Journal articles and books are cited for the following topics: early history, parity nonconservation in charged weak interactions, parity nonconservation in high‐energy polarized‐electron scattering, parity nonconservation in atoms, CPT invariance, tests of C‐invariance, CP violation in neutral kaon decay, tests of time‐reversal invariance, and search for electric dipole moments. [The letter E after an item indicates elementary level or material of general interest to persons becoming informed in the field. The letter I, for intermediate level, indicates material of a somewhat more specialized nature, and the letter A indicates rather specialized or advanced material.]

A new experimental limit on the electric dipole moment of the electron

We describe a search for the electric dipole moment de of the electron, carried out with 205Tl atoms in the ground state. The experiment makes use of the separated‐oscillating‐field magnetic‐resonance method, laser state selection, fluorescence detection, and two counter‐propagating atomic beams. Very careful attention is paid to systematic effects. The result for the atomic electric dipole moment is da=(1.6±5.0)×10−24 e cm. If we assume the theoretical ratio da/de=−600, this yields de=(−2.7±8.3)×10−27 e cm.