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Extra dimensions vs. supersymmetric interpretation of missing energy events at a linear collider (open access)

Extra dimensions vs. supersymmetric interpretation of missing energy events at a linear collider

The photon plus missing energy signature is a primary handle on two important classes of theories. Theories with large extra dimensions predict the production of photons in association with Kaluza-Klein excitations of the graviton. In supersymmetric theories with superlight gravitinos, photons can be produced in association with gravitino pairs. The signatures for these two theories are compared, and it is found that they can be distinguished by studying the photon energy distributions and scaling of the cross section with center-of-mass energy. Both these methods fail, however, if there are six extra dimensions. In that case, additional phenomena predicted by the theories would be required to narrow down the underlying causes of the photon plus missing energy signal. We also study the ability of these measurements to determine the number of extra dimensions.
Date: October 25, 2001
Creator: Gopalakrishna, Shrihari; Perelstein, Maxim & Wells, James D.
System: The UNT Digital Library
Position Resolution Studies with MSU 32-Fold Segmented HPGe Detector (open access)

Position Resolution Studies with MSU 32-Fold Segmented HPGe Detector

We present position sensitivity measurements obtained with one of the 32-fold segmented HPGe detectors from Michigan State University. These measurements were performed with a collimated beam of {sup 137}Cs gamma rays scattered by 90 degrees. This deposits 374 keV at a given location inside the crystal. A position resolution can be determined over many events by examining the digitally recorded pulse shapes on the 32 electrical contacts. If position resolution is adequate, gamma ray Compton camera imaging may be possible.
Date: October 25, 2001
Creator: Lehner, C E; Vetter, K; Kuhn, A; Schmid, G J; Beckedahl, D A; Blair, J J et al.
System: The UNT Digital Library
Low Bandwidth Vocoding using EM Sensor and Acoustic Signal Processing (open access)

Low Bandwidth Vocoding using EM Sensor and Acoustic Signal Processing

Low-power EM radar-like sensors have made it possible to measure properties of the human speech production system in real-time, without acoustic interference [1]. By combining these data with the corresponding acoustic signal, we've demonstrated an almost 10-fold bandwidth reduction in speech compression, compared to a standard 2.4 kbps LPC10 protocol used in the STU-III (Secure Terminal Unit, third generation) telephone. This paper describes a potential EM sensor/acoustic based vocoder implementation.
Date: October 25, 2001
Creator: Ng, L C; Holzrichter, J F & Larson, P E
System: The UNT Digital Library
R-Matrix Evaluation of 160 Neutron Cross Sections up to 6.3 MeV (open access)

R-Matrix Evaluation of 160 Neutron Cross Sections up to 6.3 MeV

We have evaluated {sup 16}O neutron cross sections in the resolved resonance region with the multilevel Reich-Moore code SAMMY. Resonance parameters were determined by a consistent analysis, including both Doppler and resolution broadening effects. To properly treat the {alpha} particle exit channel, an algorithm to calculate charged particle penetrabilities and shifts was incorporated into SAMMY.
Date: October 25, 2001
Creator: Sayer, R.O.
System: The UNT Digital Library