S+Au interactions at 200,4 GeV were observed using emulsion chambers, permitting measurement of pseudorapidities in the central region with precision --0.01 unit. Scaled-factorial-moment analyses are extended to bin sizes smaller than those accessible to other fixed-target experimental techniques. For a sample of 151 central collisions, moments are calculated using both "horizontal" and "vertical" analysis techniques. While the moments are found to rise (in a log-log plot) with decreasing pseudorapidity bin size 8rf, their slopes roll off to approximately zero for 8rj < 0.1.
The angular variation of the quadrupole doublet ratio for the two resolved sites in biotite single crystals is studiedby Mossbauer absorption. It is shownthat the angular variation is consistent with the assumption that the EFG principal Z-axis for the prominent M, site is distributed on a cone of half angle 20", the axis lying normal to the layer. This model is justified from the known polytypism of biotite. The lower and higher energy lines of the quadrupole doublet are identified with 13/2 and Il/z, respectively, indicating that the quadrupole coupling constant in M, site is negative.Es wird die Winkelanderung der Quadrupol-Dublettaufspaltung fur zwei aufgeloste Platze in Biotit-Einkristallen mit MoBbauerspektroskopie untersucht. Es wird gezeigt, daO die Winkeliinderung mit der Annahme konsistent ist, daO dieEFG-Haupt-2-Achse fur den besonderen M,-Platz auf einem Kegel mit dem Halbwinkel20" verteilt ist, dessen Achse zur Schicht normal liegt. Dieses Model1 wird mit dem bekannten Polytypismus von Biotit gerechtfertigt. Die Nieder-und Hochenergielinie des Quadrupoldubletts wird mit I312 bzw. 1112 identifiziert, was darauf hinweist, da13 die Quadrupolkopplungskonstante der M,-Pliitze negativ ist.
Figure 1 shows a star found in Ilford G5 nuclear emulsion irradiated by 4.5-Bev/c TT" mesons from the Berkeley Bevatron. The primary particle which is seen but which does not show in the plate is presumably a TT" meson; the very small chance that it is a K' meson does not affect the discussion.The two particles which go due north and south in the figure have respective ranges 13.7 and 9.7 microns; the angle between them is 8.7±1.0°; their point of origin is the main star to within 0.4 micron; their tracks are saturated and they presumably come to rest. Each particle gives a star of which one prong is a TT" meson, identified in the plate by its own terminal star. The Nbound particle is a uniquely identified ^H^ with Bf^ = 2.29 ± 0.61 Mev. The S-bound particle can be satisfactorily analyzed as ^H* or A^i®'®, with other possibilities remote.^ It seems unlikely that these two mesonically decaying hypernuclei are generated by the normal mechanism: the chance per star that a single mesonically decayii^ hypernucleus is found is about l.BxlO''* (our present study comprises 260 322 stars; similar information comes from Slater^); the chance that any mesonically decaying hyperfragment from such a star has a range of less than 20 microns is about 4xl0~^We suggest that a natural explanation is to be found in the formation of a short-lived E hypernucleus. The conversion reaction S + iV-*2A° within the S hypernucleus results in the formation of the two ordinary A° hypernuclei.^ Although this reaction is technically fast it is quite likely that the lifetime of a E hypernucleus is long enough to enable the hypernuclear state to be well defined. This is because: (I) the reaction goes as ^^^, and K vertices are presumed relatively weak^;( II) the scale of the nucleus is H/m^c but the conversion range is H/mxc;(III) selection rules are unusually restrictive.^ Perturbation theory, an empirical nucleon momentum distribution, pseudoscalar K-meson, and^^^ = l give a lifetime of several times 10"^° sec not sensitively dependent on the E-iV relative parity.®The immediate consequence of this speculative interpretation of our double event is that the A-N interaction is attractive."^ Thanks are due to Dr. E. Lofgren and the staff of the Berkeley Bevatron for providing the TT" irradiation and to the William Waldorf Astor Foundation for a grant that enabled it to be carried out.FIG. 1. Double-hyperf ragment event.^^He^ might be admitted but is very improbable. The possibility that this particle is a,K meson is rejected because: (I) the chance that aK meson of only 0.6 Mev emerges from a 4.5-Bev/c star is less than 10"* as is known from this and related investigations; (11) the chance that SLK meson gives on absorption a TT" meson of range as short as 4.6 mm is 0.01 or less; (III) the other prongs of the K star would have to conspire with the TT" meson to make the event acceptably analyzable as a hypernucleus decay. The possibility of a 2 hyperon is rejected with similar firmness. So is a large number of possibilities based on chance coinciden...
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