Search for a particle at 1.8 MeV through resonant Bhabha scattering.
Item
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Title
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Search for a particle at 1.8 MeV through resonant Bhabha scattering.
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Identifier
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AAI9020743
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identifier
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9020743
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Creator
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Asoka Kumar, Palakkal P. V.
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Contributor
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Adviser: Michael S. Lubell
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Date
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1990
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Language
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English
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Publisher
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City University of New York.
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Subject
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Physics, Nuclear | Physics, Elementary Particles and High Energy
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Abstract
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This thesis describes an experimental approach to a search for a particle of mass 1.8 MeV through the use of resonant Bhabha scattering. The project was motivated by the discovery of correlated back-to-back electron-positron pairs observed at GSI, Darmstadt, Germany. If the pair generation is due to the formation and subsequent decay of a new low-mass neutral particle, evidence for such a particle should be found in the production of a resonance in s-channel Bhabha scattering. In order to search for such a resonance an experiment was developed at Brookhaven National Laboratory which is sensitive to a particle of lifetime shorter than a few times 10{dollar}\sp{lcub}-13{rcub}{dollar} sec. A {dollar}\sp{lcub}22{rcub}{dollar}Na{dollar}\beta\sp +{dollar} source with A-thick W(100) transmission moderator was employed to produce a positron beam with an intensity of 5 {dollar}\times{dollar} 10{dollar}\sp{lcub}5{rcub}{dollar} {dollar}e\sp+{dollar}/sec, a half-angle divergence of less than 0.5{dollar}\sp\circ{dollar}, and a FWHM size of 1.1 mm. The beam energy spread at the target was found to be less than 1 keV(FWHM), and the high-energy contamination of the beam from the unmoderated positrons, less than 1 {dollar}e\sp+{dollar}/sec. The thesis contains descriptions of the positron beam generation, extraction, acceleration and transport, as well as summaries of the GSI studies, prior searches for a neutral particle, and preliminary measurements at Brookhaven.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
