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Il Nuovo Cimento (1955-1965)

, Volume 24, Issue 4, pp 698–712 | Cite as

Analysis of an alpha-particle interaction of energy ~ 1012 eV per nucleon

  • P. L. Jain
Article

Summary

A nuclear interaction of type 3 + 34α along with two energetic secondaries of type 2+ 12p(S1) and 4+ 19p(S2), which are presumably produced by the nucleons from the breakup of the original α-particle, were observed in nuclear emulsion. The primary as well as the secondary events were considered as nucleon-nucleon interactions and were analysed by measuring the energies and angles of their secondary particles. The energy as calculated from the angular distribution of the shower particles of the primary and the two secondary events(S1 and S2) is 900 GeV, 412 GeV and 400 GeV per nucleon, respectively (as calculated from Castagnoli’s formula with a factor 1/2). The energy of the primary as well as the secondary event S2 is in agreement approximately with an independent estimate obtained from the total energy dissipated in either case. But the energy of the secondary jet S1 when analysed the same way as that of the other two jets indicates that its energy, as determined from the angular distribution, is overstimated at least by a factor of two. The average transverse momentum of the shower particles is ~ 0.30 BeV/c. The energy and the angles of shower particles of these three events are transferred to the c.m.s. which shows sharp collimation of particles of high energy at small angles with the shower axis. The energy distribution in c.m.s. for these three events is peaked towards low values but shows a tail at high-energy values extending up to 2.5 GeV. Analysis of the primary event is consistent with the « two fireball » model.

Riassunto

Si è osservata nell’emulsione una interazione nucleare del tipo 3 + 34α con due secondari energetici del tipo 2+12p(S1) e 4+19p(S2), che sono presumibilmente prodotti dal nucleo in seguito alla frattura della particella α originaria. Sia l’evento primario che quelli secondari sono stati considerati interazioni nuoleone-nucleone e sono stati analizzati misurando le energie e gli angoli delle loro particelle secondarie. L’energia dell’evento primario e dei due secondari S1 ed S2, dedotta dalla distribuzione angolare delle particelle dello sciame è, rispettivamente, 900 GeV, 412 GeV e 400 GeV per nucleone (in base alla formula di Castagnoli con fattore 1/2). L’energia dell’evento primario e del secondario S2 è approssimativamente in accordo con una stima indipendente in base all’energia totale dissipata nei due casi. Ma per quanto riguarda il getto secondario S1, analizzato nella stessa maniera degli altri due, risulta che la sua energia, determinata in base alle distribuzioni angolari, è sopravalutata per un fattore di almeno 2. L’impulso trasversale medio delle particelle dello sciame è ~ 0.30 GeV/c. L’energia e gli angoli delle particelle dello sciame composto da questi tre eventi vengono trasportati nel sistema del centro di massa e ne risulta una netta collimazione delle particelle di alta energia e piccolo angolo con Fasse dello sciame. La distribuzione dell’energia nel sistema del centro di massa per questi tre eventi ha un picco verso i valori bassi ma ha una coda ai valori delle alte energie estendentesi sino a 2.5 GeV. L’analisi dell’evento primario è coerente col modello delle « due palle di fuoco ».

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Copyright information

© Società Italiana di Fisica 1962

Authors and Affiliations

  • P. L. Jain
    • 1
  1. 1.Department of PhysicsUniversity of BuffaloBuffalo

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