H

Studies of Hyperons and Antihyperons in Nuclei

“…Using different Ξ-absorbing stable secondary target nuclei 9 Be, 10 B, 11 B, 12 C and 13 C one finds that different double hypernuclei dominate for each target [35]. Thus combining the information shown in Fig.…”

“…In 2001 the BNL experiment E906 reported the observation of the 4 ΛΛ H hypernucleus by measuring the sequential pionic decays after a (K − ,K + ) reaction deposited two units of strangeness in a 9 Be target [44] (see Fig. 3).…”

“…Fig. 4 shows the predicted relative probabilities for the production of particle stable twin and double hypernuclei in the E906 experiment after the capture and conversion of a stopped Ξ − in a secondary 9 Be target Ξ − + 9 Be→ 10 ΛΛ Li * . As before a Ξ − binding energy of 0.5 MeV seems reasonable corresponding to an 10 ΛΛ Li excitation of about 29 MeV.…”

“…Let us first discuss the structure at (114,104) MeV/c which has been attributed to double hypernuclei decays. Generally the production of double hypernuclei is energetically favored over the production of twins: all possible channels with twin-production lie energetically significantly above the thresholds for 9 ΛΛ Li, 7 ΛΛ He and 6 ΛΛ He production in case of the 10 ΛΛ Li compound picture. Correspondingly the production of 3 Λ H and 6 Λ He twins which has been suggested as a possible source of the peak structure around (114,104) MeV/c [45], is in our model by a factor of 30 lower than the 7 ΛΛ He production probability.…”

“…First investigations of antiproton-nucleus scattering cross sections [3,4,5] showed however disagreement with a strong attractive potential. Later, X-ray transitions in antiprotonic atoms [6,7,8,9,10] gave also hints for an attractive potential albeit with large uncertainties [11,12]. More comprehensive studies [13] of antiprotonic X-rays as well as recent analyses of the production of antiprotons in reactions with heavy ions resulted in attractive real potentials in the range of about -100 to -150 MeV [14,15,16].…”