Summary
A calculation is made of the Λ0-nucleon scattering cross-section at 75 and 150 MeV laboratory energies, based on a phenomenological central potential with a hard core to describe the Λ0-nucleon interaction. The potential is chosen so as to give agreement with hyperfragment data and at the same time to have reasonable properties from a meson-theoretical viewpoint. With this potential the Λ0-nucleon cross-section is calculated numerically, assuming that scattering occurs only in states with orbital angular momentum ⩽ 2. The result is that the Λ0-nucleon cross-section is approximately constant in the energy range considered. The variation is from 26 mb at 75 MeV to 21 mb at 150 MeV without a spin-orbit force, and from 34 mb at 75 MeV to 32 mb at 150 MeV with a spin-orbit force. These results are consistent with the very preliminary measurement ofCrawford et al.
Riassunto
Si calcola la sezione d’urto per lo scattering Λ0-nucleone a 75 e 150 MeV nel sistema del laboratorio basandosi su un potenziale centrale fenomenologico con un hard core per descrivere l’interazione Λ0-nucleone. Il potenziale è scelto in modo da dare accordo coi dati sugli iperframmenti e contemporaneamente avere proprietà compatibili col punto di vista della teoria dei mesoni. Con questo potenziale si calcola numericamente la sezione d’urto Λ0-nucleone, assumendo che lo scattering avvenga solo in stati con momento angolare orbitale 2. Risulta che la sezione d’urto Λ0-nucleone è pressochè costante nel campo d’energia considerato. La variazione è da 26 mb a 75 MeV a 21 mb a 150 MeV senza la forza spin-orbita, e da 34 mb a 75 MeV a 32 mb a 150 MeV con la forza spin-orbita. Questi risultati si accordano con le misure del tutto preliminari diCrawford et al.
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References
See, for example,R. H. Dalitz andB. W. Downs:Phys. Rev. 111, 967 (1958), and references contained therein.
F. S. Crawford, M. Cresti, M. L. Good, F. T. Solmitz, M. L. Stevenson, andH. K. Ticho:Phys. Rev. Lett.,2, 174 (1959).
D. B. Lichtenberg andM. Ross:Phys. Rev.,107, 1714 (1957).
D. B. Lichtenberg:Nuovo Cimento,8, 463 (1958).
One fermi equals 10−13 cm.
J. M. Blatt andV. F. Weisskopf:Theoretical Nuclear Physics, (New York, 1952) p. 56.
A subsequent calculation with a better trial wave function (D. Truong:Bull. Am. Phys. Soc.,4, 38 (1959) indicates thatV 0 should be ∼ (10 ÷ 20)% smaller than the value given here. However, when the authors became aware of this work, calculations were already finished and were not repeated.
See ref. (4) andR. H. Dalitz andB. W. Downs:Phys. Rev.,110, 958 (1958) (and to be published) for estimates of this ratio. Our value may be too small by ∼ 20%.
P. S. Signell andR. E. Marshak:Phys. Rev.,109, 1229 (1958).
S. Gartenhaus:Phys. Rev.,100, 900 (1955).
Subsequently,P. S. Signell, R. Zinn, andR. E. Marshak:Phys. Rev. Lett.,1, 416 (1958) have found that a spin-orbit potential with different parameters fits the nucleon-nucleon scattering somewhat better. However, the improvement was not great enough to warrant repeating our calculation. See in this connectionM. H. Hull, K. D. Pyatt, C. R. Fischer andG. Breit:Phys. Rev. Lett. 2, 264 (1959).
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Work supported in part by an All-University Research Grant.
This calculation was previously reported inBull. Am. Phys. Soc.,3, 402 (1958).
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Kovacs, J.S., Lichtenberg, D.B. Scattering of Λ0 hyperons by nucleons at intermediate energies. Nuovo Cim 13, 371–375 (1959). https://doi.org/10.1007/BF02732946
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DOI: https://doi.org/10.1007/BF02732946