Isotopic spin and mass quantization

Production of heavy unstable particles by 1.37-bev pions

Production of V 1 0 Particles by Negative Pions in Hydrogen

Summary In a stack of stripped photographic emulsions, twenty events of type 2+0 n have been observed, in each of which the outgoing particles are a proton and a negative π-meson respectively; the latter particle was identified by the characteristic star it produced when brought to rest in the emulsion. Assuming that each of these events represents the decay in flight of a neutral hyperon according to the scheme Λ 0→π -+P+Q, values of the energy release Q have been calculated. In eleven of the events the proton could be traced to the end of its range; the energies of both particles could then be deduced using appropriate range-energy relations. In the remaining nine examples, the energy of the proton was deduced from grain density considerations and was accordingly less well determined.

LXI. On the mass of the Λ0-particle

In a series of pictures taken with a multiplate cloud chamber we have observed the decay of a number of neutral $V$ particles which originated in nuclear interactions produced inside the cloud chamber. Most of these $V$ particles were found to decay into a proton and a $\ensuremath{\pi}$-meson with a $Q$ value of 37 Mev. Strong evidence is presented to support the hypothesis that no neutral secondary particle is produced. The lifetime was found to be (3.5\ifmmode\pm\else\textpm\fi{}1.2)\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}10}$ second.Four neutral $V$ particles were found which certainly belong to a different group. The decay products of these particles are probably two $\ensuremath{\pi}$-mesons. The nature and energy of the nuclear interactions which produce neutral $V$ particles are discussed.

Study of Neutral V Particles Observed in a Multiplate Cloud Chamber

In a set of 23,000 cloud-chamber photographs taken in a study of penetrating showers, 134 examples of the decay of neutral $V$-particles, and 18 of the decay of charged $V$-particles, were observed. An analysis of the 152 examples leads to the following principal conclusions: (1) $V$-particles result from the impact of mesons and probably also of nucleons, upon nuclei. (2) $V$-particles are generally produced singly and not in pairs. (3) Two independent kinds of data, one based on measurements of angles and other purely spatial relationships, and the other based on measurements of momentum and specific ionization, lead to the conclusion that more than 80 percent of these neutral $V$-particles decayed by the production of a heavy positive and a light negative particle. The mass of the heavy positive particle in most instances was consistent with that of a proton, but in a few cases may have been somewhat less. The negative particle appeared most often to be a $\ensuremath{\pi}$-meson, although in a few cases a $\ensuremath{\mu}$-meson was indicated. In about 7 percent of the cases, the positive particle was light and had a mass consistent with that of a $\ensuremath{\pi}$- or $\ensuremath{\mu}$-meson. In these cases the mass of the negative particle was not well determined. So far, therefore, in these investigations, there is no direct evidence that a neutral $V$-particle decays into two $\ensuremath{\pi}$-mesons, or into a positive $\ensuremath{\pi}$-meson and a negatively charged proton, although a few cases may be so interpreted. (4) The data are consistent with the assumption of a two-body decay for a majority of the neutral $V$-particles, and therefore a rather extensive analysis is given based upon this assumption. (5) The energy release, or $Q$-value, of the decay of neutral $V$-particles was computed, on the assumption of a two-body decay, for those cases in which the production of a heavy positive particle was clearly indicated, and where momentum measurements were possible. On the assumption of a decay into a proton and a ${\ensuremath{\pi}}^{\ensuremath{-}}$ meson, the $Q$-values obtained ranged from 10 Mev to about 100 Mev. The great majority of cases however, may be described in terms of discrete $Q$-values at 35\ifmmode\pm\else\textpm\fi{}3 Mev, and 75\ifmmode\pm\else\textpm\fi{}5 Mev, although, of course, the data are consistent with distributions about these values. For the same set of cases, if the positive particle is assumed to be as light even as $1250{m}_{e}$, and/or the negative particle is assumed to be a $\ensuremath{\mu}$-meson, the distribution of $Q$-values is not greatly changed, and the apparent necessity for at least two different $Q$-values remains. In those few cases mentioned in (3) above, in which the positive particle was light, and in which the mass of the negative particle was undetermined, the energy release, computed on the basis of a two-body decay, depends upon the assumed identity of the decay products, and is about 100-130 Mev for the assumption that two $\ensuremath{\pi}$-mesons are produced, about 50-80 Mev for a positive $\ensuremath{\pi}$-meson and a negative $\ensuremath{\tau}$-meson, and about 30-80 Mev for a positive $\ensuremath{\pi}$-meson and a negative proton. (6) The rest mean lifetime of ${V}^{0}$ particles, which appear to yield protons and ${\ensuremath{\pi}}^{\ensuremath{-}}$-mesons as decay products, was found to be 1.6\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}10}$ sec for 26 cases having $Q$-values greater than 50 Mev, and 2.9\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}10}$ sec for 48 cases having $Q$-values less than 50 Mev, on the assumption of a two-body decay. In view of the rather poor statistics, the above two lifetimes are consistent with a single value, and lead to an average of 2.5\ifmmode\pm\else\textpm\fi{}0.7\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}10}$ sec. The above lifetimes are not appreciably changed if a multibody decay of the neutral $V$-particle is assumed. (7) The data are not adequate to distinguish conclusively between a two-body and a multi-body decay, and, therefore, a discussion is also given in terms of a variety of possible decay schemes of the neutral $V$-particle.

The Decay of V 0 Particles

In a set of 23,000 cloud-chamber photographs taken in a study of penetrating showers, 134 examples of the decay of neutral V-particles, and 18 of the decay of charged V-particles, were observed. An analysis of the 152 examples leads to the following principal conclusions: (1) V-particles result from the impact of mesons and probably also of nucleons, upon nuclei. (2) V-particles are generally produced singly and not in pairs. (3) Two independent kinds of data, one based on measurements of angles and other purely spatial relationships, and the other based on measurements of momentum and specific ionization, lead to the conclusion that more than 80 percent of these neutral V-particles decayed by the production of a heavy positive and a light negative particle. The mass of the heavy positive particle in most instances was consistent with that of a proton, but in a few cases may have been somewhat less. The negative particle appeared most often to be a π-meson, although in a few cases a μ-meson was indicated. In about 7 percent of the cases, the positive particle was light and had a mass consistent with that of a π- or μ-meson. In these cases the mass of the negative particle was not well determined. So far, therefore, in these investigations, there is no direct evidence that a neutral V-particle decays into two π-mesons, or into a positive π-meson and a negatively charged proton, although a few cases may be so interpreted. (4) The data are consistent with the assumption of a two-body decay for a majority of the neutral V-particles, and therefore a rather extensive analysis is given based upon this assumption. (5) The energy release, or Q-value, of the decay of neutral V-particles was computed, on the assumption of a two-body decay, for those cases in which the production of a heavy positive particle was clearly indicated, and where momentum measurements were possible. On the assumption of a decay into a proton and a π- meson, the Q-values obtained ranged from 10 Mev to about 100 Mev. The great majority of cases however, may be described in terms of discrete Q-values at 35±3 Mev, and 75±5 Mev, although, of course, the data are consistent with distributions about these values. For the same set of cases, if the positive particle is assumed to be as light even as 1250me, and/or the negative particle is assumed to be a μ-meson, the distribution of Q-values is not greatly changed, and the apparent necessity for at least two different Q-values remains. In those few cases mentioned in (3) above, in which the positive particle was light, and in which the mass of the negative particle was undetermined, the energy release, computed on the basis of a two-body decay, depends upon the assumed identity of the decay products, and is about 100-130 Mev for the assumption that two π-mesons are produced, about 50-80 Mev for a positive π-meson and a negative τ-meson, and about 30-80 Mev for a positive π-meson and a negative proton. (6) The rest mean lifetime of V0 particles, which appear to yield protons and π--mesons as decay products, was found to be 1.6×10-10 sec for 26 cases having Q-values greater than 50 Mev, and 2.9×10-10 sec for 48 cases having Q-values less than 50 Mev, on the assumption of a two-body decay. In view of the rather poor statistics, the above two lifetimes are consistent with a single value, and lead to an average of 2.5±0.7×10-10 sec. The above lifetimes are not appreciably changed if a multibody decay of the neutral V-particle is assumed. (7) The data are not adequate to distinguish conclusively between a two-body and a multi-body decay, and, therefore, a discussion is also given in terms of a variety of possible decay schemes of the neutral V-particle.

The decay of V0 particles

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

S. D. Wanlass

Author Tools

Chat about Author

Papers

The Decay of V 0 Particles

The decay of V0 particles