scholarly journals Precision measurement of the weak charge of the proton and parity violation in the N → Δ transition

2019 ◽  
Author(s):  
Anna Lee
Keyword(s):  
Parity Violation ◽  
Precision Measurement ◽  
Weak Charge

scholarly journals ATOMIC PARITY VIOLATION: PRINCIPLES, RECENT RESULTS, PRESENT MOTIVATIONS

2005 ◽  
Vol 20 (06) ◽  
pp. 375-389 ◽  
Author(s):  
J. GUÉNA ◽  
M. LINTZ ◽  
M.-A. BOUCHIAT
Keyword(s):  
Parity Violation ◽  
Precision Measurement ◽  
Calibration Procedure ◽  
New Physics ◽  
Stimulated Emission ◽  
Atomic Parity Violation ◽  
Weak Charge ◽  
The Status ◽  
Left Right Asymmetry

We review the progress made in the determination of the weak charge, QW, 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 σ deviation of QW 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.

scholarly journals Determination of the Proton's Weak Charge and Its Constraints on the Standard Model

2019 ◽  
Vol 69 (1) ◽  
pp. 191-217 ◽  
Author(s):  
Roger D. Carlini ◽  
Willem T.H. van Oers ◽  
Mark L. Pitt ◽  
Gregory R. Smith
Keyword(s):  
Standard Model ◽  
Parity Violation ◽  
Valence Quark ◽  
Weak Mixing Angle ◽  
Weak Charge ◽  
Mixing Angle ◽  
The Standard Model ◽  
History Of ◽  
Bsm Physics

This article discusses some of the history of parity-violation experiments that culminated in the Qweak experiment, which provided the first determination of the proton's weak charge [Formula: see text]. The guiding principles necessary to the success of that experiment are outlined, followed by a brief description of the Qweak experiment. Several consistent methods used to determine [Formula: see text] from the asymmetry measured in the Qweak experiment are explained in detail. The weak mixing angle sin2θw determined from [Formula: see text] is compared with results from other experiments. A description of the procedure for using the [Formula: see text] result on the proton to set TeV-scale limits for new parity-violating semileptonic physics beyond the Standard Model (BSM) is presented. By also considering atomic parity-violation results on cesium, the article shows how this result can be generalized to set limits on BSM physics, which couples to any combination of valence quark flavors. Finally, the discovery space available to future weak-charge measurements is explored.

Sign in / Sign up

Export Citation Format

Share Document