The spectrometer and target systems for hypernuclear physics at the Mainz Microtron

Abstract

At the Mainz Microtron MAMI, the technique of high-resolution spectroscopy of decay-pions in strangeness electroproduction has been established to extract Λ ground state binding energies of light hyperfragments. In a first series of measurements, using a momentum setting covering 133MeV/c and a 9Be target, the Λ4H binding energy was determined with unprecedented precision. The current measurement employs a novel lithium target of 50 mm length and only 0.75 mm thickness to precisely determine the hypertriton binding energy in a setting covering its two-body decay momentum of 114MeV/c. The experiment aims for statistical and systematic errors of approximately 20keV and is running during the summer of 2022.