Measurement of the parity violating6S−7Stransition amplitude in cesium achieved within2×10−13

Abstract

We exploit the process of asymmetry amplification by stimulated emission which provides an original method for parity violation (PV) measurements in a highly forbidden atomic transition. The method involves measurements of a chiral, transient, optical gain of a cesium vapor on the 7S − 6P 3/2 transition, probed after it is excited by an intense, linearly polarized, collinear laser, tuned to resonance for one hyperfine line of the forbidden 6S-7S transition in a longitudinal electric field. We report here a 3.5 fold increase, of the one-second-measurement sensitivity, and subsequent reduction by a factor of 3.5 of the statistical accuracy compared with our previous result [J. Guéna et al., Phys. Rev. Lett. 90, 143001 (2003)]. Decisive improvements to the set-up include an increased repetition rate, better extinction of the probe beam at the end of the probe pulse and, for the first time to our knowledge, the following: a polarization-tilt magnifier, quasi-suppression of beam reflections at the cell windows, and a Cs cell with electrically conductive windows. We also present real-time tests of systematic effects, consistency checks on the data, as well as a 1% accurate measurement of the electric field seen by the atoms, from atomic signals. PV measurements performed in seven different vapor cells agree within the statistical error. Our present result is compatible with the more precise Boulder result within our present relative statistical accuracy of 2.6%, corresponding to a 2 × 10 −13 atomic-unit uncertainty in E pv 1 . Theoretical motivations for further measurements are emphasized and we give a brief overview of a recent proposal that would allow the uncertainty to be reduced to the 0.1% level by creating conditions where asymmetry amplification is much greater.

Towards measuring nuclear-spin-dependent and isotopic-chain atomic parity violation in ytterbium

“…The effect of the Stark-PNC interference is to change the relative strength of the two extreme components of the transition with respect to the central component. Expressions (5,6) show explicitly that the PNC effect reverses with both E and θ.…”

“…1). The PNC-induced 6s 2 1 S 0 → 5d6s 3 D 1 transition amplitude has been calculated [1,2,3] to be two orders of magnitude larger than the PNC amplitude in cesium where high-precision measurements have been carried out [4,5].…”

Combined QCD and electroweak analysis of HERA data

“…12. Also shown are measurements from LEP þ SLC [44], D0 [50], CDF [51], CMS [52], ATLAS [53] and LHCb [54], all at the scale of the Z mass, as well as a fixed-target neutrino-nucleon measurement from NuTeV [48], a fixed target electron-electron measurement from E158 [55] and the result from atomic cesium [56][57][58] at lower scales. This is the first time that data from a single experimental configuration were used to determine sin 2 θ W at different This t-channel determination is in agreement with the PDG14 value of 80.385 AE 0.015 GeV, which is dominated by s-channel processes.…”

Pump-probe measurement of atomic parity violation in cesium with a precision of 2.6%

“…We briefly recall the experimental setup, more extensively described in [17], [1], where the absolute frequency stabilisation of the laser sources is presented. The excitation and probe beams are recombined using a dichroic mirror (see Fig.…”

“…In this paper we present the PV measurements we have performed in Cs [1], by making use of a probe beam superposed with the beam that drives the 6S-7S forbidden transition. After the probe beam has been amplified by stimulated emission of the excited vapour, its polarisation is analysed so as to extract the PV asymmetry, calibrated against a parity conserving signal.…”