Study of hypernuclei by associated production

1997

We study the production of $\Lambda$ hyperons in $p + A$ reactions on the basis of a BUU transport approach from 1.1 to 1.9 GeV and evaluate the properties of the hypernuclei produced in particular with respect to their momentum distribution in the laboratory frame. Due to elastic $\Lambda N$ scattering large cross sections for the production of heavy hypernuclei in the order of 100 - 400 $\mu b$ are predicted for p + U at 1.5 - 1.9 GeV laboratory energy. Whereas the $K^+ Y$ production channels are expected to be only slightly modified in the nuclear medium, the antikaon production should be enhanced substantially due to large attractive $K^-$ selfenergies in dense matter. We predict an enhancement of the inclusive $K^-$ yield in p + $^{208}$Pb collisions of a factor of $\approx$ 10 at 2 GeV laboratory energy.

Nuclear Physics A, 2013

Physical Review Letters, 2013

Progress of Theoretical Physics Supplement, 1994

Results are reviewed on the systematic study of :E hypernuclei with (stopped K-, ~r±) reactions performed by Tokyo group. Formation and decay properties of :E hypernuclei obtained from 12 C(K-, ~r+) and 4 He(K-, ~r±) reactions are summarized. The first observation of the :E hypernuclear bound state (~He) and information of isospin/spin dependence of :E·nucleus interaction from the 4 He data are discussed in detail and they are compared with recent theoretical estimations.

Nuclear Physics A, 2013

We investigate the production of a cascade hyperon (Ξ) and bound Ξ hypernuclei in the (K − , K +) reaction on proton and nuclear targets, respectively, within a covariant effective Lagrangian model. The K + Ξ − production vertex is described by excitation, propagation and decay of Λ and Σ resonance states in the initial collision of a K − meson with a free or bound proton in the incident channel. The parameters of the resonance vertices are taken from previous studies and SU(3) symmetry considerations. The model is able to provide a good description of the available data on total and differential cross sections for the p(K − , K +)Ξ − reaction. The same mechanism was used to describe the hypernuclear production reactions 12 C(K − , K +) 12 Ξ − Be and 28 Si(K − , K +) 28 Ξ − Mg, where Ξ bound state spinors calculated within a phenomenological model have been employed. Both the elementary and hypernuclear production cross sections are dominated by the contributions from the Λ(1520) intermediate resonant state. The beam momentum dependence of the 0 • differential cross sections for the formation of the Ξ hypernuclei is found to be remarkably different from what has been observed previously in the impulse approximation model calculations.

We critically review the ¤¤ dynamics by examining LL and L-nucleon phe- nomenological potentials in the study of the bound state properties of double-L hypernuclei LL 6He, LL 10Be, LL 14C, LL 18O, LL 22Ne, LL 26Mg, 30 ¤¤Si, 34 ¤¤S, 38 ¤¤Ar, 42 ¤¤Ca, 92 ¤¤Zr and 142 ¤¤ Ce, 210 ¤¤Pb in the framework of (core+¤+¤) three-body model. An e®ective ¤N potential is obtained by folding the phenomenological ¤N potential into the density distribution of core nuclei. The former two cases (i.e. 6 ¤¤He and 10 ¤¤Be) are revisited to justify the correctness of the present potential model. Assuming the same po- tential model, we predicted some of the structural properties of heavier double-¤ hypernuclei. The hyperspherical harmonics expansion method, which is an essen- tially exact method, has been employed for the three-body system. A convergence in binding energy up to 0:25% for Kmax = 20 has been achieved. In our calculation we have made no approximation in restricting the allowed l-values of the ...

Physics Letters B, 2014

We have carried out an experiment to search for a neutron-rich hypernucleus, 6 Λ H, by the 6 Li(π -, K + ) reaction at p π -=1.2 GeV/c. The obtained missing mass spectrum with an estimated energy resolution of 3.2 MeV (FWHM) showed no peak structure corresponding to the 6 Λ H hypernucleus neither below nor above the 4 Λ H+2n particle decay threshold. An upper limit of the production cross section for the bound 6 Λ H hypernucleus was estimated to be 1.2 nb/sr at 90% confidence level.

Nuclear Physics A, 1993

The low-energy, background free and tagged K-following the ~(1020) decay produced at the DAONE ~-faetory in Frascati represent a unique opportunity to carry out a dedicated program of hypernuclear physics with K-at rest. In this paper we give a survey of this challenging field and we describe the performances of a magnetic spectrometer designed for precise measurements of hypemuclei energy levels and of their decays modes.

2017

The production of strangeness on the nucleon and hyperon and hypernuclear production in heavy ion collisions at relativistic energies and in antiproton annihilation on nuclei is discussed. The reaction process is described by transport theory with focus on S = -2 channels and a comparison of different model interactions. The interactions of hyperons in nuclear matter is investigated in a novel SU(3) approach. An outlook to the S = -3 sector and Ω -physics is given.

Progress in Particle and Nuclear Physics, 2008

We present an overview of a fully covariant formulation of describing the hypernuclear production with hadronic and electromagnetic probes. This theory is based on an effective Lagrangian picture and it focuses on production amplitudes that are described via creation, propagation and decay into relevant channel of N * (1650), N * (1710) and N * (1720) intermediate baryonic resonance states in the initial collision of the projectile with one of the target nucleons. The bound state nucleon and hyperon wave functions are obtained by solving the Dirac equation with appropriate scalar and vector potentials. Specific examples are discussed for reactions which are of interest to current and future experiments on the hypernuclear production.