arXiv subjects

D. H. Perkins

Publications and source records attributed to D. H. Perkins.

5 recordsLinked to original sources

arXiv2002

Tri-Bimaximal Mixing and the Neutrino Oscillation Data

Following recent results from the SNO solar neutrino experiment and the K2K long-baseline neutrino experiment, the combined existing data on neutrino oscillations now point strongly to a specific form for the lepton mixing matrix, with effective bimaximal mixing of $ν_μ$ and $ν_τ$ at the atmospheric scale and effective trimaximal mixing for $ν_e$ with $ν_μ$ and $ν_τ$ at the solar scale (hence `tri-bimaximal' mixing). We give simple mass-matrices leading to tri-bimaximal mixing, and discuss its relation to the Fritzsch-Xing democratic ansatz.

hep-ph↗

arXiv1999

A Redetermination of the Neutrino Mass-Squared Difference in Tri-Maximal Mixing with Terrestrial Matter Effects

We re-fit for the neutrino mass-squared difference $Δm^2$ in the threefold maximal (ie. tri-maximal) mixing scenario using recent CHOOZ and SUPER-K data, taking account of matter effects in the Earth. While matter effects have little influence on reactor experiments and proposed long-baseline accelerator experiments with $L \simlt 1000 km$, they are highly significant for atmospheric experiments, suppressing naturally $ν_e$ mixing and enhancing $ν_μ - ν_τ$ mixing, so as to effectively remove the experimental distinction between threefold maximal and twofold maximal $ν_μ-ν_τ$ mixing. Threefold maximal mixing is fully consistent with the CHOOZ and SUPER-K data and the best-fit value for the neutrino mass-squared difference is $Δm^2 = (0.98 \pm^{0.30}_{0.23}) \times 10^{-3} eV^2$.

hep-ph↗

arXiv1997

Further Evidence for Threefold Maximal Lepton Mixing and a Hierarchical Spectrum of Neutrino Mass-Squared Differences

The phenomenological case for threefold maximal lepton mixing is strengthened by more detailed comparison with existing data. The atmospheric neutrino data are self-consistent and in good agreement with the threefold maximal mixing prediction R = 2/3 (chi-squared/dof = 4.3/5, CL = 51%). Including partially con- tained event data, the zenith angle dependence also points to threefold maximal mixing, ruling-out a range of mixing schemes, including that of Fritzsch and Xing. Accounting for `de facto' uncertainties in solar neutrino fluxes, the solar neutrino data (including HOMESTAKE) are shown to be consistent with threefold maximal mixing (chi-squared/dof = 5.1/3, CL = 16%), as is the upper limit from the LSND appearance experiment. Detailed pred- ictions for forthcoming long-base-line reactor and accelerator experiments are presented.

hep-ph↗

arXiv1996

Measurement of the atmospheric neutrino flavour composition in Soudan 2

The atmospheric neutrino flavour ratio measured using a 1.52 kton-year exposure of Soudan 2 is found to be 0.72 +- 0.19 +0.05 -0.07 relative to the expected value from a Monte Carlo calculation. The possible background of interactions of neutrons and photons produced in muon interactions in the rock surrounding the detector has been investigated and is shown not to produce low values of the ratio.

hep-ex↗

arXiv1996

No Mikheyev-Smirnov-Wolfenstein Effect in Maximal Mixing

We investigate the possible influence of the MSW effect on the expectations for the solar neutrino experiments in the maximal mixing scenario suggested by the atmospheric neutrino data. A direct numerical calculation of matter induced effects in the Sun shows that the naive vacuum predictions are left completely undisturbed in the particular case of maximal mixing, so that the MSW effect turns out to be unobservable. We give a qualitative explanation of this result.

hep-ph↗