Dr. Randy Johnson

A.B., Princeton University, 1969

Ph.D., University of California, Berkeley, 1975

Area of Interest: Experimental High Energy Physics



Revised - January, 2000

Email Address:

Randy.Johnson@uc.edu

Telephone: 513-556-0528
Fax: 513-556-3425

Mailing address (also UPS address):

Physics Department, ML 11
Room 417, Geology/Physics Building
University of Cincinnati
Cincinnati, OH 45221

Index

Research - NuTeV

NuTeV is a high energy neutrino experiment designed to make very precise determinations of two parameters, "rho" and "sin^2 theta_W", of the standard model of electroweak interactions. These parameters are simply related to the ratios of the quark and the anti-quark weak cross sections and to the ratio of charged current to neutral current cross sections. These parameters, if they continue to be consistent with the standard limits on the Higgs mass. If they are not consistent, they will indicate new physics beyond the standard model. In addition to this fundamental measurement, NuTeV will also be able to measure the quark composition of nucleons and will be able to look for exotic events such as those coming from neutral heavy leptons or from neutrino oscillations. From the detection of dilepton events, we will be able to measure the dynamical charm quark mass. More information about the NuTeV experiment can be found on the NuTeV home page.

A Cincinnati graduate student, Masoud Vakili, collaborated in setting up and running NuTeV. He wrote his thesis on data obtained on the earlier CCFR experiment. That thesis explored the possibility that neutrinos can scatter collectively off groups of nucleons and not just from single nucleons or quarks. A second graduate student, Narumon Suwonjandee, is analyzing the charged current events in the NuTeV data to determine the structure of the proton.

Research - BooNE

BooNE is a new neutrino experiment designed to verify or disprove the recent Los Alamos result that found evidence for neutrino oscillations. LSND (the Los Alamos experiment) found an excess of electron type neutrinos in their detector. An explanation of this result is that the muon neutrinos, which were the predominate type of neutrinos produced, "oscillated" into electron neutrinos. Such a result necessarily imples that the neutrinos have mass.

The BooNE experiment is designed to definitely prove or disprove the LSND result. If LSND is correct we should see an excess of hundreds of electron neutrinos. If LSND is wrong, we will disprove it at the 5 sigma level.

BooNE uses protons from the 8 GeV Booster at Fermilab. We will interact those protons in a beryllium target and produce pions. these pions will decay to muons and muon neutrinos is a 50 m decay pipe. 500 m of dirt will absorb all other particles except the penetrating neutrinos. We will detect a small fraction of the neutrinos in a 12 m diameter sphere of mineral oil. The type of resulting particles from the interaction will be determined by the pattern of Cerenkov light detected on the wall of the sphere.

Cincinnati has two main responsibilities in this project: 1) doing radiation calculations to assure the laboratory that we are safely handling the incoming proton beam; and 2) specifying and testing the mineral oil that will be used in the detector. Narumon Suwonjandee has been doing the radiation calculations with me in addition to her NuTeV analysis work and a UC undergraduate, Steve Tomassettii has been helping with the mineral oil specification.

Boone is presently under construction and is on schedule to take data in December, 2001. More information can be found on the BooNE home pages at Fermilab or Los Alamos.

Recent Publications

Evidence for Diffractive Charm Production in nu_mu Fe and nubar_mu Fe Scattering at the Tevatron, T Adams, et al. (to be published in Phys. Rev. D (2000))

Search for a 33.9 MeV/c^2 Neutral Particle in Pion Decay, J.A. Formaggio, et al., Phys. Rev. Lett. 83, 4943 (1999).

Nuclear Structure Functions in the Large x Large Q^2 Kinematic Region in Neutrino Deep Inelastic Scattering, M. Vakili, et al., to be published in Phys. Rev. D (2000).

A Limit on Muon-Neutrino (Anti-Muon Neutrino)-->Tau Neutrino (Anit-Tau Neutrino) Oscillations from a Precision Measurement of Neutrino- Nucleon Neutral Current Interactions, K.S. McFarland, D. Naples, et al., Phys. Rev. Letts. 75, 3993 (1995).

Teaching

Modern Physics for Engineers

Relativity, an introduction to quantum mechanics, and a survey of modern physics topics. Course web page includes links to syllabus, problem sets, study aids, and previous exams.

Particle Physics

Particle Physics is a two quarter graduate course that serves as an introduction to high energy physics. Course web page includes syllabus, Mathematica examples, and problem sets.

Graduate Electrodynamics

This three quarter graduate course covers the topics in Jackson plus conformal mappings and finite element solutions to Laplace's equation. Mathematica is used for problem solutions and examples. Course web page includes links to the syllabus, Mathematica examples, and problem sets.

Statistics for Experimental Physicists

I have recently also taught a course in statistical analysis for physicist. Course web page can also be found on the web.

Personal History

I came to neutrino experiments by a round-about route. I did my Ph.D. thesis on hadronic interactions, an experiment performed at Fermilab just after it opened, and continued those studies when I worked at Brookhaven National Laboratory. I came to Cincinnati in 1984 and began working on the SLD experiment at SLAC. The group at Cincinnati built and installed the drift volumes for the endcap Cerenkov Ring Imaging Detectors in that experiment. After installation, I joined the NuTeV collaboration.