2022 CAP Congress / Congrès de l'ACP 2022

(I) Chiral Belle: Upgrading SuperKEKB with a Polarized Electron Beam

7 Jun 2022, 11:50

25m

MDCL 1105 (McMaster University)

Invited Speaker / Conférencier(ère) invité(e) Symposia Day (PPD) - New Directions in Accelerator-Based Experiments T2-3 New Directions in Accelerator-Based Experiments: Future Collider Experiments - Energy and Precision Frontier (PPD) | Nouvelles voies fondées sur des accélérateurs: expériences futures avec collisionneurs - frontière d'énergie et de précision (PPD)

Speaker

Michael Roney

Description

Upgrading the SuperKEKB e+e− collider with polarized electron beams is under consideration as it opens a new program of precision electroweak physics at the $\mathrm{{\rm Y}}(4S)$. This Chiral Belle physics program includes determining ${\sin }^2{\theta }_W$ via separate left-right asymmetry ($A_{LR}$) measurements in $e^{+}{e}^{-}$ annihilations to pairs of electrons, muons, taus, charm and b-quarks using the Belle II detector. The precision that can be obtained matches that of the LEP/SLC world average and enables the probing of neutral current couplings with unprecedented precision in a manner sensitive to their running. At SuperKEKB, the measurements of the individual neutral current vector coupling constants to b-quarks, c-quarks and muons in particular will be substantially more precise than current world averages and the current $3\sigma$ discrepancy between the SLC $A_{LR}$ measurements and LEP $A_{FB}^b$ measurements of ${\sin }^2{\theta }_W^{eff}$ can be addressed. It can also provide the highest precision measurements of neutral current universality ratios. In addition, having a polarized electron beam enables measurements of tau lepton properties, including the tau g-2, with unrivaled precision. This presentation will cover the physics motivation and status of the R&D necessary for the upgrades to achieve and measure the SuperKEKB e- beam polarization.

Presentation materials

ChiralBelle-CAP2022-7June2022.pdf