Summary
Evidence suggesting the existence of charged particles of mass ∼ 550 me has been reported byAlikhanian, Šostakovič, Dadaian, Fedorov andDeriagin. A search has been made for these particles in a photographic emulsion stack exposed for five months at an altitude of 11 000 ft,λ=24° N at Khillanmarg (Kashmir). The central plate of the stack was scanned for all tracks, with dip angles <45°, due to particles brought to rest within it. A total of 5 790 tracks was obtained in this scan. Of these tracks, 2 613 were due to particles, with ranges < 5 mm, emerging from nuclear disintegrations; these were not considered further. Mass measurements were carried out on the remaining 3 177 tracks by the grain density vs. residual range method; the range interval involved is (3÷40) g/cm2. The 3 177 tracks investigated were found to be due to 1 018 μ-mesons, 168 π-mesons and 1 991 particles of mass ⩾850 me. No particle with a mass estimated to be between 390 me and 850 me has been observed. Five such particles are to be expected on the abundance of ∼ 1/2% compared to μ-mesons (in the same range interval) quoted byAlikhanian et al. The question of the existence of such particles is discussed in the light of this and other experiments.
Riassunto
Indizi che suggeriscono l’esistenza di particelle cariche di massa ∼ 550 me sono stati riferiti daAlihanian, Šostakovič, Dadaian, Fedorov eDeriagin. Queste particelle sono state ricercate in una pila di lastre esposte per cinque mesi ad un’altezza di 11 000 ft.,λ=24 ° N a Khillanmarg (Kashmir). Nella lastra di centro della pila sono state esaminate tutte le tracce, con angoli di dip <45°, dovute a particelle venute a fermarsi nel suo interno. In questa ricerca si sono trovate in totale 5 790 tracce. Di queste tracce 2613 erano dovute a particelle, con percorsi <5 mm, che derivavano da disintegrazioni nucleari; queste non vennero ulteriormente prese in considerazione. Sulle rimanenti 3177 tracce furono eseguite misure di massa col metodo del rapporto fra densità di grani e percorso residuo; l’intervallo di percorso considerato è (3÷40) g/cm2. Si trovò che le 3177 tracce esaminate erano dovute a 1 018 mesoni μ, 168 mesoni π e 1991 particelle di massa ⩾850 me. Non si è osservata alcuna particella di massa stimata fra 380 me e 850 me. Sulla base di una percentuale del 1/2°% rispetto ai mesoni μ (nello stesso intervallo di percorso) riportatoAlihanian et al., ci si dovrebbero aspettare 5 di queste particelle. La questione dell’esistenza di tali particelle viene discussa alla luce di questa ed altre prove.
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Durga Prasad, N., Menon, M.G.K. & Sharma, O.P. An experiment to investigate the existence of charged particles of mass ∼ 550 me . Nuovo Cim 14, 1332–1341 (1959). https://doi.org/10.1007/BF02962354
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DOI: https://doi.org/10.1007/BF02962354