The Cryogenic Dark Matter Search (CDMS-II) Experiment: First Results from the Soudan Mine

Thesis/Dissertation · Wed Sep 01 04:00:00 EDT 2004

DOI:https://doi.org/10.2172/15020277· OSTI ID:15020277

Chang, Clarence Leeder ^[1]

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1. Stanford Univ., CA (United States)

There is an abundance of evidence that the majority of the mass of the universe is in the form of non-baryonic non-luminous matter that was non-relativistic at the time when matter began to dominate the energy density. Weakly Interacting Massive Particles, or WIMPs, are attractive cold dark matter candidates because they would have a relic abundance today of ~0.1 which is consistent with precision cosmological measurements. WIMPs are also well motivated theoretically. Many minimal supersymmetric extensions of the Standard Model have WIMPs in the form of the lightest supersymmetric partner, typically taken to be the neutralino. The CDMS II experiment searches for WIMPs via their elastic scattering off of nuclei. The experiment uses Ge and Si ZIP detectors, operated at <50 mK, which simultaneously measure the ionization and athermal phonons produced by the scattering of an external particle. The dominant background for the experiment comes from electromagnetic interactions taking place very close to the detector surface. Analysis of the phonon signal from these interactions makes it possible to discriminate them from interactions caused by WIMPs. This thesis presents the details of an important aspect of the phonon pulse shape analysis known as the ''Lookup Table Correction''. The Lookup Table Correction is a position dependent calibration of the ZIP phonon response which improves the rejection of events scattering near the detector surface. The CDMS collaboration has recently commissioned its experimental installation at the Soudan Mine. This thesis presents an analysis of the data from the first WIMP search at the Soudan Mine. The results of this analysis set the world's lowest exclusion limit making the CDMS II experiment at Soudan the most sensitive WIMP search to this date.

• Research Organization: Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC02-76CH03000
• OSTI ID: 15020277
• Report Number(s): FERMILAB-THESIS--2004-54
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ABUNDANCE
ACCURACY
ASTROPHYSICS
Astrophysics
Experiment-HEP
CALIBRATION
CRYOGENICS
ELASTIC SCATTERING
ELECTROMAGNETIC INTERACTIONS
ENERGY DENSITY
IONIZATION
NONLUMINOUS MATTER
NUCLEI
PHONONS
SCATTERING
SHAPE
STANDARD MODEL
UNIVERSE