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HK: Fachverband Physik der Hadronen und Kerne

HK 70: Hadron Structure and Spectroscopy IX

HK 70.3: Talk

Thursday, March 14, 2024, 16:30–16:45, HBR 62: EG 18

Design of a luminosity monitor for the P2 parity violating experiment at MESA — Sebastian Baunack¹, Maarten Boonekamp^2,4, Boris Gläser¹, Rahima Krini¹, Frank Maas^1,2,3, Moran Neher¹, •Tobias Rimke¹, David Rodriguez Pineiro², and Malte Wilfert¹ for the P2 collaboration — ¹Institut für Kernphysik, Johannes Gutenberg-Universität Mainz — ²Helmholtz-Institut Mainz, Johannes Gutenberg-Universität Mainz — ³PRISMA Cluster of Excellence, Johannes Gutenberg-Universität Mainz — ⁴IRFU, CEA, Université Paris-Saclay, Gif-sur-Yvette, France

The P2 experiment at the future MESA accelerator in Mainz plans to measure the weak mixing angle sin²(θ_W) in parity violating elastic electron-proton scattering. The aim of the experiment is a very precise measurement of the weak mixing angle with an accuracy of 0.14% at a low four-momentum transfer of Q²=4.5· 10⁻³ GeV². In order to achieve this accuracy, it is necessary to monitor the stability of the electron beam and the liquid hydrogen target. Any helicity correlated fluctuation of the target density leads to false asymmetries.

Therefore, it is planned to install a luminosity monitor in forward direction close to the beam axis. The motivation and challenges for designing an air Cherenkov luminosity monitor will be discussed in this talk. Furthermore, I show the current prototype design with results from promising tests run with the electron beam of the MAMI accelerator and detailed simulation studies with the prototype.

Keywords: Parity-violating electron scattering; Weak mixing angle; Cherenkov detector; P2 experiment; MESA