Low-background balloon-borne direct search for ionizing massive particles as a component of the dark galactic halo matter.

Persistent Link:
http://hdl.handle.net/10150/186654
Title:
Low-background balloon-borne direct search for ionizing massive particles as a component of the dark galactic halo matter.
Author:
McGuire, Patrick Charles.
Issue Date:
1994
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
A dark matter (DM) search experiment was flown on the IMAX balloon payload, which tested the hypothesis that a minor component of the dark matter in the Galactic halo is composed of ionizing (dE/dx > 1 \ MeV/g/cm² or σ > 2 x 10⁻²⁰ cm²) supermassive particles (mₓ ∈ [10⁴,10¹²] GeV/c²) that cannot penetrate the atmosphere due to their low velocities (β ∈ [0.0003, 0.0025]). The DM search experiment consisted of a delayed coincidence between four ∼ 2400 cm² plastic scintillation detectors, with a total acceptance of ∼ 100 cm² sr. In order to search for ultra-slow particles which do not slow down in the IMAX telescope, the experiment contained TDCs which measured the time-delays T(i,i+1) ∈ [0.3, 14.0] μs between hits in successive counters ∼ 1% precision. Using the first 5 hours of data at float altitude (5 g/cm² residual atmosphere), we observed ∼ 5 candidate non-slowing dark matter events, consistent with the background from accidental coincidences of 4 events. This implies that the DM flux is less than 6.5 x 10⁻⁶cm⁻²s⁻¹sr⁻¹ (95% C.L.). Similar results were also obtained for particles which slow down in the counter telescope. This experiment effectively closes much of a previously unconstrained 'window' in the mass/cross-section joint parameter space for massive particles as the dominant halo DM, and implies that for certain regions of this parameter space massive particles cannot be more than one part in 10⁵ by mass of all the DM. These results can also directly constrain 'light' magnetic monopoles and neutraCHAMPs in a previously unconstrained mass region mₓ ∈ [10⁶,10⁹] GeV.
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Dissertations, Academic.; Astrophysics.
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Physics; Graduate College
Degree Grantor:
University of Arizona
Committee Chair:
Bowen, Theodore

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleLow-background balloon-borne direct search for ionizing massive particles as a component of the dark galactic halo matter.en_US
dc.creatorMcGuire, Patrick Charles.en_US
dc.contributor.authorMcGuire, Patrick Charles.en_US
dc.date.issued1994en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractA dark matter (DM) search experiment was flown on the IMAX balloon payload, which tested the hypothesis that a minor component of the dark matter in the Galactic halo is composed of ionizing (dE/dx > 1 \ MeV/g/cm² or σ > 2 x 10⁻²⁰ cm²) supermassive particles (mₓ ∈ [10⁴,10¹²] GeV/c²) that cannot penetrate the atmosphere due to their low velocities (β ∈ [0.0003, 0.0025]). The DM search experiment consisted of a delayed coincidence between four ∼ 2400 cm² plastic scintillation detectors, with a total acceptance of ∼ 100 cm² sr. In order to search for ultra-slow particles which do not slow down in the IMAX telescope, the experiment contained TDCs which measured the time-delays T(i,i+1) ∈ [0.3, 14.0] μs between hits in successive counters ∼ 1% precision. Using the first 5 hours of data at float altitude (5 g/cm² residual atmosphere), we observed ∼ 5 candidate non-slowing dark matter events, consistent with the background from accidental coincidences of 4 events. This implies that the DM flux is less than 6.5 x 10⁻⁶cm⁻²s⁻¹sr⁻¹ (95% C.L.). Similar results were also obtained for particles which slow down in the counter telescope. This experiment effectively closes much of a previously unconstrained 'window' in the mass/cross-section joint parameter space for massive particles as the dominant halo DM, and implies that for certain regions of this parameter space massive particles cannot be more than one part in 10⁵ by mass of all the DM. These results can also directly constrain 'light' magnetic monopoles and neutraCHAMPs in a previously unconstrained mass region mₓ ∈ [10⁶,10⁹] GeV.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectDissertations, Academic.en_US
dc.subjectAstrophysics.en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplinePhysicsen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.chairBowen, Theodoreen_US
dc.contributor.committeememberShupe, Michaelen_US
dc.contributor.committeememberMelia, Fulvioen_US
dc.contributor.committeememberBurrows, Adamen_US
dc.contributor.committeememberHill, Henryen_US
dc.identifier.proquest9424987en_US
dc.identifier.oclc722845969en_US
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