[BTeam] the challenge of MOLLER

[Jay Benesch]

Colleagues, 

excerpt from http://arxiv.org/abs/2410.14768 page 1

Enhancing Precision of Signal Correction in PVES Experiments: The Impact of Bayesian Analysis on the Results of the QWeak and MOLLER Experiments
Elham Gorgannejad, Wouter Deconinck, David S. Armstrong
Comments: 10 pages, 5 figures, submitted to Physical Review C 

The Continuous Electron Beam Accelerator Facility
(CEBAF) [5] employs superconducting linacs to deliver a
continuous electron beam, resulting in stable beam conditions
 ideal for conducting parity-violation experiments.
CEBAF has hosted significant experiments such as the
Qweak experiment [6], which measured the weak charge
of the proton using a 1.165 GeV electron beam at 180
µA, achieving an asymmetry measurement precision of
AP V = −226.5 ± 9.3 ppb (parts per billion). Moreover,
the upcoming MOLLER experiment [7], planned to
begin in 2026, will utilize an 11 GeV electron beam with a
current of 65 µA to probe the weak charge of the electron,
aiming to measure an expected parity violation of
AP V ≈ −32 ppb with a precision of ±0.54 ppb.

--------------------

While the relative error needed by MOLLER is 40% of that obtained by Qweak, the absolute error needed is only 6% of that achieved.  Also compare the size of the transverse asymmetries in Tables 1 and 2: MOLLER  _really_ needs pure longitudinal polarization.  Daily tenth-degree Wien filter changes have been discussed.  

Jay