Has the neutral double hypernucleus nΛΛ4 been observed?

Abstract The BNL-AGS E906 experiment was the first fully electronic experiment to produce and study double hypernuclei with large statistics. Two dominant structures were observed in the correlated π − – π − momentum matrix at ( p π − H , p π − L ) = ( 133 , 114 ) MeV / c and at ( 114 , 104 ) MeV / c . In this work we argue that the interpretation of the structure at ( 133 , 114 ) MeV / c in terms of Λ 3 H+ Λ 4 H pairs is questionable. We show, that neither a scenario where these single-Λ hypernuclei are produced after capture of a stopped Ξ − by a 9Be nucleus nor interactions of energetic Ξ − with 9Be nuclei in the target material can produce a sufficient amount of such twin pairs. We have…

An infrared light-guide based target positioning system for operation in a harsh environment

In the PANDA experiment's hypernuclear and hyperatom setup, a positioning system for the primary production target is required, which will be located in the center of the solenoid magnet, in ultra-high vacuum, and exposed to high radiation levels. In this work, a prototype for a positioning sensor was built using a bisected light guide for infrared light and a low-priced readout system based on microcontrollers. In contrast to many modern positioning systems that require electronics in direct proximity, this setup has no active electronic components close to the moving parts. The prototype system was operated with a resolution of better than 5$\micro$m, and with a repeatability of better th…

Status of J-PARC E07: Systematic study of double strangeness nuclei with hybrid emulsion method

J-PARC E07 is the most complex emulsion experiment to date investigating double hypernuclei with a hybrid emulsion method. This experiment aims to detect 104 Ξ− stop events, ten times more events than the past experiments. Thus, an unequivocal identification of several new double hypernuclei is expected. The beam exposure has been completed at the K1.8 beam line of the J-PARC hadron facility in June 2017. The photographic development of all emulsion sheets has also been completed in February 2018. The emulsion sheets are presently being analyzed with dedicated optical microscopes. Current statistics is comparable to that of E373 and so far 10 events of 3-vertices topology have been detected…

Strangeness nuclear physics at P¯ANDA