Commissioning of the hypertriton binding energy measurement at MAMI

¹ Institute for Nuclear Physics, Johannes Gutenberg University Mainz, 55099 Mainz, Germany
² Graduate School of Science, Tohoku University, Sendai, Miyagi 980-8578, Japan
³ Helmholtz Institute Mainz, GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Johannes Gutenberg University Mainz, 55099 Mainz, Germany
⁴ Key Laboratory of Nuclear Physics and Ion-beam Application (MOE), Institute of Modern Physics, Fudan University, Shanghai 200433, China
⁵ Shanghai Research Center for Theoretical Nuclear Physics, NSFC and Fudan University, Shanghai 200438, China
⁶ Department of Physics, Graduate School of Science, The University of Tokyo, Tokyo 113-0033, Japan

^* e-mail: eckert@uni-mainz.de
^** Now at Thomas Jefferson National Accelerator Facility (JLab), Newport News, Virginia 23606, USA

Published online: 9 November 2022

Abstract

A high-precision hypernuclear experiment has been commissioned at the Mainz Microtron (MAMI) to determine the hypertriton Λ binding energy via decay-pion spectroscopy. The method has been successfully pioneered with ⁴_ΛH studies in the last decade. The experiment makes use of a novel high luminosity lithium target with a length of 45mm while being only 0.75mm thick to keep momentum smearing of the decay pions low. The target-to-beam alignment as well as the observation of the deposited heat is achieved with a newly developed thermal imaging system. Together with a precise beam energy determination via the undulator light interference method a recalibration of the magnetic spectrometers will be done to obtain a statistical and systematic error of about 20 keV. The experiment started in the summer of 2022 and initial optimization studies for luminosity and data quality are presented.