10 research outputs found
Atomic Parity Violation : Principles, Recent Results, Present Motivations
We review the progress made in the determination of the weak charge, Q\_w, of
the cesium nucleus which raises the status of Atomic Parity Violation
measurements to that of a precision electroweak test. Not only is it necessary
to have a precision measurement of the electroweak asymmetry in the highly
forbidden 6S-7S transition, but one also needs a precise calibration procedure.
The 1999 precision measurement by the Boulder group implied a 2.5 sigma
deviation of Q\_w from the theoretical prediction. This triggered many particle
physicist suggestions as well as examination by atomic theoretical physicists
of several sources of corrections. After about three years the disagreement was
removed without appealing to "New Physics". Concurrently, an original
experimental approach was developed in our group for more than a decade. It is
based on detection by stimulated emission with amplification of the left- right
asymmetry. We present our decisive, recent progress together with our latest
results. We emphasize the important impact for electroweak theory, of future
measurements in cesium possibly pushed to the 0.1% level. Other possible
approaches are currently explored in several atoms
Resonant nonlinear magneto-optical effects in atoms
In this article, we review the history, current status, physical mechanisms,
experimental methods, and applications of nonlinear magneto-optical effects in
atomic vapors. We begin by describing the pioneering work of Macaluso and
Corbino over a century ago on linear magneto-optical effects (in which the
properties of the medium do not depend on the light power) in the vicinity of
atomic resonances, and contrast these effects with various nonlinear
magneto-optical phenomena that have been studied both theoretically and
experimentally since the late 1960s. In recent years, the field of nonlinear
magneto-optics has experienced a revival of interest that has led to a number
of developments, including the observation of ultra-narrow (1-Hz)
magneto-optical resonances, applications in sensitive magnetometry, nonlinear
magneto-optical tomography, and the possibility of a search for parity- and
time-reversal-invariance violation in atoms.Comment: 51 pages, 23 figures, to appear in Rev. Mod. Phys. in Oct. 2002,
Figure added, typos corrected, text edited for clarit
Polarizabilities and parity non-conservation in the Cs atom and limits on the deviation from the standard electroweak model
A semi-empirical calculation of the 6s - 7s Stark amplitude in Cs
has been performed using the most accurate measurements and calculations of the
electromagnetic amplitudes available. This is then used to extract the
parameters of the electroweak theory from experimental data. The results are:
, weak charge of Cs , deviation from the Standard model and limit on the mass of the extra Z-boson in SO(10) model
.Comment: 8 pages; submitted to Phys. Rev.