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Prog. Theor. Phys. Vol. 50 No. 6 (1973) pp. 1879-1893
On the Life Time of X-Particles Found by Niu et al.
Shigeki Tasaka and
Yoshiaki Yamamoto
Department of Physics, Konan University, Motoyama, Kobe
(Received March 22, 1973)
Abstract:
Out of 44 jet showers observed by the Bristol-Bombay Group to have originated in the producing layer of their ballon-borne emulsion chamber (1961), eight have one or two cascade shower cores each of which is emitted within an angle smaller than those of the remaining γ-rays by a factor of 1/2 with an energy greater than those of the latter by a factor of 3. Although, in each event, a quantity of its energy divided by its emission angle excels those of the remaining γ-rays at least by a factor of 20. If we assume that every highest energy γ-ray in these events is a decay product of π0-meson, we can show that it is very much probable that these eight groups of cores have originated from the decay π0 of the X-particles found recently by Niu et al. The life time τ0 of the X-particles is then estimated to be 1.5<τ0/(10-13 sec)<100 and 2.6<τ0/(10-13 sec)<175 for the two typical decay modes X→π+π0 and X→Σ+π0, respectively. The estimated values are rather long compared with those reported by Niu et al., but are consistent with the theoretical estimation by Ogawa et al.
URL :
http://ptp.ipap.jp/link?PTP/50/1879/
DOI : 10.1143/PTP.50.1879
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