The experiments with the High Resolution Kaon Spectrometer at JLab Hall C and the new spectroscopy of ${}^{12}_{\Lambda} ext{B}$ hypernuclei

摘要

Since the pioneering experiment, E89-009 studying hypernuclear spectroscopyusing the $(e,e^{\prime}K^+)$ reaction was completed, two additionalexperiments, E01-011 and E05-115, were performed at Jefferson Lab. These laterexperiments used a modified experimental design, the "tilt method", todramatically suppress the large electromagnetic background, and allowed for asubstantial increase in luminosity. Additionally, a new kaon spectrometer, HKS(E01-011), a new electron spectrometer, HES, and a new splitting magnet wereadded to produce precision, high-resolution hypernuclear spectroscopy. Thesetwo experiments, E01-011 and E05-115, resulted in two new data sets, producingsub-MeV energy resolution in the spectra of ${}^{7}_{\Lambda}\text{He}$,${}^{12}_{\Lambda}\text{B}$ and ${}^{28}_{\Lambda}\text{Al}$ and${}^{7}_{\Lambda}\text{He}$, ${}^{10}_{\Lambda}\text{Be}$,${}^{12}_{\Lambda}\text{B}$ and ${}^{52}_{\Lambda}\text{V}$. All threeexperiments obtained a ${}^{12}_{\Lambda}\text{B}$, spectrum, which is the mostcharacteristic $p$-shell hypernucleus and is commonly used for calibration.Independent analyses of these different experiments demonstrate excellentconsistency and provide the clearest level structure to date of thishypernucleus as produced by the $(e,e^{\prime}K^+)$ reaction. This paperpresents details of these experiments, and the extraction and analysis of theobserved ${}^{12}_{\Lambda}\text{B}$ spectrum.