Speaker
Description
Missing-mass spectroscopy by using the $(e,e^{\prime}K^{+})$ reaction was developed at Jefferson Lab (JLab). The energy resolution of 0.5 to 1 MeV/$c^{2}$ in FWHM is achievable thanks to a high quality beam provided by JLab and high resolution spectrometers dedicated to hypernuclear measurements. In addition, one of important features is an accurate energy calibration by using $\Lambda$ and $\Sigma^{0}$ productions from a proton target, leading to the energy accuracy of $|\Delta B_{\Lambda}|<100~{\rm keV}$.
We are preparing for experiments in which light to heavy mass targets will be used [E12-19-002 (A = 3, 4), E12-15-008 (A = 40, 48), E12-20-013 (A = 208)]. I will present an experimental overview and the expected results for $^{3}_{\Lambda}$H ($1/2^{+}$ or $3/2^{+}$) and $^{4}_{\Lambda}$H ($1^{+}$) measurements which have been approved by JLab PAC last year. We aim to measure $\Lambda$ binding energies of these $\Lambda$ hypernuclei with the energy accuracy of less than 100 keV to investigate a puzzle of contradiction between the lifetime and binding energy of hypertriton, and to study the $\Lambda$N charge symmetry breaking.