Frank T. Solmitz

K− interactions in hydrogen

SummaryK−-meson from the Bevatron have been stopped in a 10 in. hydrogen bubble chamber. This is a preliminary report on the first 137 interactions. There are photographs confirming the existence of the Ō0 and the Σ0, which must be lighter than the Σ− by at least several MeV. Σ’s are produced more profusely than Λ’s in the absorption of K− by protons: we observe the production rations Σ− : Σ+ : Σ0 : Λ ⋍ 4 : 2 : 2 : 1. The large observed absorption cross-section of slow K− by protons suggests that the interaction takes place inp states as well as ins states. There is evidence that the spin of the Σ is greater than 1/2. There is no evidence for parity doublets. Our data rule out the proposed selection rule ΔI=±1/2. The accepted value for the mean life τΛ is checked, and we find τ∑=(1.83±0.26)·10−10 s and τ∑=(0.86±0.17)·10−10 s.RiassuntoSi presenta una relazione preliminare su 137 interazioni a riposo di mesoni K− prodotti dal Bevatrone con i protoni dell’Idrogeno liquido di una camera a bolle di 25 cm di diametro. Si sono ottenute fotografie confermanti l’esistenza della Ō0 e della Σ0; la massa di quest’ultima risulta minore di quella della Σ− di almeno qualche MeV. L’assorbimento dei K− da parte dei protoni dà luogo più frequentemente alla produzione di Σ che di Λ; le abbondanze da noi osservate stanno nei rapporti: Σ− : Σ+ : Σ0 : Λ ∼ 4 : 2 : 2 : 1. Il fatto che la sezione d’urto osservata per assorbimento dei K− di bassa energia è alta, suggerisce che l’interazione ha luogo sia in statip che in statis. I dati indicano anche che lo spin della Σ è maggiore di 1/2, mentre non danno alcuna indicazione dell’esistenza dei doppietti di parità ed escludono la validità della regola di selezione proposta ΔI=±1/2. Si dà una verifica del valore accettato per la vita media τΜ e si trova τ∑=(1.83±0.26)·10−10 s e τ∑=(0.86±0.17)·10−10 s.

New phenomena in ν interactions

Several events have been observed in neutrino interactions which have an e+ and a K°s decay in the final state along with the conventional μ−. A discussion of their detection and relation to dimuon events will be presented. The significance of the associated strange particles and related kinematic quantities will be discussed.

ON THE ANALYSIS OF BUBBLE CHAMBER TRACKS

Since its invention by Glaser in 1953, the bubble chamber has become a most valuable tool in high-energy physics. It combines a number of advantages of various older methods of particle detection: it offers high spatial resolution, rapid accumulation of data, some time resolution, and some choice of the nucleus whose interaction one wants to study (bubble chambers have been made to operate with a large number of different liquids, including H{sub 2}, D{sub 2}, He, Xe, and several hydrocarbons). In order to exploit the advantages of spatial resolution and rapid data accumulation, high-speed high-precision analysis procedures must be developed. In this article they discuss some of the problems posed by such analysis. The discussion is based largely on experience gained in performing hydrogen bubble chamber experiments with the University of Californias Bevatron (6-Bev proton synchrotron).

Interactions of K Mesons in Hydrogen

Author(s): Alvarez, Luis W.; Bradner, Hugh; Falk-Vairant, Paul; Gow, J. Donald; Rosenfeld, Arthur H.; Solmitz, Frank T.; Tripp, Robert D.