Explore the vast range of titles available.

In this work we propose a new method to measure the evolution of the neutron skin thickness between different isotopes. We consider antiproton–nucleus interactions close to the production threshold of ΛΛ̅ and Σ − Λ̅ pairs. At low energies, ΛΛ̅ pairs are produced in p̅ + p collisions, while Σ − Λ̅ pairs can only be produced in p̅ + n interactions. Measuring these cross sections provides information on the neutron skin thickness.

In the K1.8 beam-line at Hadron Experimental Facility of J-PARC, a new magnetic spectrometer S-2S is being installed. S-2S was designed to achieve a high momentum resolution of Δ p / p = 6 × 10 −4 in FWHM. Several strangeness-physics programs which require the high resolution will be realized by S-2S. The present article introduces J-PARC E70 (missing-mass spectroscopy of Ξ 12 Be) and E94 (missing-mass spectroscopy of Λ 7 Li, Λ 10 B, and Λ 12 C) experiments.

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 Λ H 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.

New possibilities of hypernuclear studies at modern electron accelerators based on recently developed radio frequency photomultiplier tubes are discussed.

The BNL-AGS E906 experiment was the first fully electronic experiment to produce and study double hypernuclei with large statistics. Unfortunately, the interpretation of the measured π−−π− momentum correlation is still blurry because the hypothesized production of \\(_ ^3H+_ ^4H\\) pairs remains questionable. We show, that neither a scenario where the hypernuclei are produced after the capture of a stopped Ξ− by a 9Be nucleus nor interactions of energetic Ξ− with 9 Be nuclei in the target material can produce a sufficient amount of such pairs. We have therefore explored the conjecture that decays of the\\(_^_^4n\\)may be responsible for the observed structure. Indeed, the inclusion of \\(_^_^4n\\) with a two-body π− branching ratio of 50% in the statistical multifragmentation model allows to describe the E906 data remarkably well.

The BNL-AGS E906 experiment was the first fully electronic experiment to produce and study double hypernuclei with large statistics. Unfortunately, the interpretation of the measured π−−π− momentum correlation is still blurry because the hypothesized production of Λ3H+Λ4H pairs remains questionable. We show, that neither a scenario where the hypernuclei are produced after the capture of a stopped Ξ− by a 9Be nucleus nor interactions of energetic Ξ− with 9 Be nuclei in the target material can produce a sufficient amount of such pairs. We have therefore explored the conjecture that decays of then∧∧4may be responsible for the observed structure. Indeed, the inclusion of n∧∧4 with a two-body π− branching ratio of 50% in the statistical multifragmentation model allows to describe the E906 data remarkably well.

A schematic Monte Carlo simulation is used to examine the potential of the \\( P ANDA\\) experiment to extract information on the interaction of antihyperons in nuclei by exclusive hyperon-antihyperon pair production close to threshold in antiproton nucleus interactions. Due to energy and momentum conservation event-by-event transverse momentum correlations of the produced hyperon and antihyperons contain information on the difference between their potentials. It is demonstrated that for \\(\\) and \\(\\) pairs produced at antiproton momenta of 1.66 GeV/c and 2.9 GeV/c, respectively, the asymmetry is sufficiently sensitive even if the density as well as the momentum dependencies of the potentials are considered.

An electron scattering experiment to search for the trineutron state \\(^3n\\) by reaction \\( ^4He(e,~e'p^+)^3n\\) is designed for the A1 facility at Mainzer Microtron. The detailed principles, setup, and simulation of this experiment are presented. With the momenta of the scattered electron, the produced proton and \\(^+\\) from the reaction measured by three spectrometers with their triple coincidence, the missing mass spectrum of \\(^3n\\) can be obtained. The production rate of \\(^3n\\) based on the cross section of the reaction and a MC simulation is estimated to be about 1.5 per day, which can provide a confidence level of the signal greater than 5\\(\\) with a beam time longer than 16 days. According to a MC simulation that evaluates the energy losses of particles in materials and the performance of three spectrometers, the estimated resolution and the predicted shape of the missing mass spectrum are presented. This work provides a new experimental concept for the search for multineutron states in future experiments with an electron beam.

We propose a new method to study the evolution of the neutron periphery between different isotopes by considering antiproton--nucleus interactions close to the production threshold of \\( \\) and \\(^- \\) pairs. At low energies, \\( \\) pairs are produced in \\(p +p\\) collisions, while \\(^- \\) pairs can only be produced in \\(p +n\\) interactions. Within a simple geometrical picture we show that the double ratio for the production of \\(^- \\) and \\( \\) pairs for two different isotopes are related to the variation of the neutron skin thickness between the two nuclei. Performing high statistics calculations with the Gieß en Boltzmann--Uehling--Uhlenbeck (GiBUU) transport model for several isotope pairs covering a wide range of elements we verify a strong correlation between the double ratio from the full transport simulations and the schematic model. This correlation enables us to quantify the potential of the proposed method for precise studies of neutron skin variations in isotope chains.

Hypernuclear research will be one of the main topics addressed by the \\(P\\)anda experiment at the planned Facility for Anti-proton and Ion Research FAIR at Darmstadt, Germany. A copious production of Ξ-hyperons at a dedicated internal target in the stored anti-proton beam is expected, which will enable the high-precision γ-spectroscopy of double strange systems for the first time. In addition to the general purpose \\(P\\)anda setup, the hypernuclear experiments require an active secondary target of silicon layers and absorber material as well as high purity germanium (HPGe) crystals as γ-detectors. The design of the setup and the development of these detectors is progressing: a first HPGe crystal with a new electromechanical cooling system was prepared and the properties of a silicon strip detector as a prototype to be used in the secondary target were studied. Simultaneously to the hardware projects, detailed Monte Carlo simulations were performed to predict the yield of particle stable hypernuclei. With the help of the Monte Carlo a procedure for ΛΛ-hypernuclei identification by the detection and correlation of the weak decay pions was developed.