arXiv subjects

Loretta M. Johnson

Publications and source records attributed to Loretta M. Johnson.

4 recordsLinked to original sources

arXiv2006

Prospects for Non-Standard Interactions at MiniBooNE

MiniBooNE is expected to soon report analysis of their closed data set, and we here consider what effect direct non-standard neutrino interactions would have on their observations. Current direct limits on non-standard interactions make interpretation of a $ν_e$ signal at MiniBooNE as three-flavor oscillations plus direct interactions untenable. However, $ν_τ$ from non-standard interactions at the source could contribute to a $ν_μ$ deficit which may be observable if non-standard interactions are sizable.

hep-ph↗

arXiv1999

Revising Neutrino Oscillation Parameter Space With Direct Flavor-Changing Interactions

We formulate direct, neutrino flavor-changing interactions in a framework that fits smoothly with the parameterization of two-and three-state mixing of massive neutrino states. We show that even small direct interaction strengths could have important consequences for the interpretation of currently running and proposed oscillation experiments. The oscillation amplitude and the borders of the allowed regions in two-and three-flavor mixing parameter space can be sensitieve to the presence of direct interactions when the transition probability is small. We use extensively the high sensitivity of the NOMAD experiment to illustrate potentially large effects from small, direct flavor violation. In the purely leptonic sector, we find that the clean muon neutrino and electron neutrino beams from a muon collider could provide the sharpest tests of direct flavor violation.

hep-ph↗

arXiv1998

Fitting direct interaction pieces into neutrino puzzles

We develop a framework and unified, compact notation to include neutrino direct interaction effects with neutrino oscillations for a wide class of low-energy, effective four-Fermi interactions. Modest flavor-violating interaction strengths can make significant changes in the boundaries in $ΔM^2 \leftrightarrow sin^2 2θ$ and in $tan^2 θ_{13} \leftrightarrow tan^2 θ_{23} parameter space. We draw examples from the L-R symmetric and $MSSM + \slash R$ models and find the recently reported decay-at-rest $μ\leftrightarrow e$ transition probability can be described without oscillations in L-R symmetric models.

hep-ph↗

arXiv1997

Extending Sensitivity for Low-Mass Neutral Heavy Lepton Searches

We point out the importance of two-body final states of weak isosinglet neutral heavy leptons predicted in several models of new physics beyond the standard model. We concentrate on muon-type neutral heavy leptons $L_μ^0$ with mass $M<2$ GeV which can be searched for with increased sensitivity at a new round of neutrino experiments at CERN and Fermilab. Providing explicit decay rate formulae for the $e e ν$, $eμν$, $μμν$, $πμ$, $ρμ$, and $a_1μ$ final states, we use general scaling features to estimate sensitivity of $L_μ^0$ searches in current and future experiments, emphasizing the importance of the $πμ$ decay mode.

hep-ph↗