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S. P. Rosen

Publications and source records attributed to S. P. Rosen.

11 recordsLinked to original sources
arXiv2000

A Mass Matrix for Atmospheric, Solar, and LSND Neutrino Oscillations

We construct a mass matrix for the four neutrino flavors, three active and one sterile, needed to fit oscillations in all three neutrino experiments: atmospheric, solar, and LSND, simultaneously. It organizes the neutrinos into two doublets whose central values are about 1 eV apart, and whose splittings are of the order of 10^(-3) eV. Atmospheric neutrino oscillations are described as maximal mixing within the upper doublet, and solar as the same within the lower doublet. Then LSND is a weak transition from one doublet to the other. We comment on the Majorana versus Dirac nature of the active neutrinos and show that our mass matrix can be derived from an S_2 x S_2 permutation symmetry plus an equal splitting rule.

hep-ph↗
arXiv1999

Comment on the broadening of the $^7$Be neutrino line in vacuum oscillation solutions of the solar neutrino

We consider the effect of thermal broadening of the $^7$Be neutrino on vacuum oscillation solutions of the solar neutrino problem and analyze the conditions under which the electron-neutrino survival probability must be averaged over neutrino energy. For "just-so" solutions with $Δm^2$ of order $5 \times 10^{-11}~{\rm eV}^2$ averaging is not necessary, but for much larger values, it is. We analyze the effective broadening due to the extended production region in the Sun and find similar results. We also comment on the possibility of seasonal variations of the $^7$Be neutrino signal.

hep-ph↗
arXiv1999

Another Look at Just-So Solar Neutrino Oscillations

We take another look at ``Just-So'' solar neutrino oscillations, characterizing them by the energy $E_{π/2}$ at which the distance-varying angle is $π/2$, instead of the usual $Δm^2$. The rising spectrum recently observed by SuperKamiokande is consistent with $E_{π/2}\sim$ 6-9 MeV and marginally with 48 MeV. The pp neutrinos must then be reduced to one-half the standard solar model prediction, and $^7$Be neutrinos must make up a significant part of the SAGE and GALLEX gallium signal. For $E_{π/2}$ close to 9 and 48 MeV, the $^7$Be neutrinos will also show a large seasonal variation, emphasizing the importance of direct measurements of the $^7$Be neutrinos.

hep-ph↗
arXiv1996

Searching for the MSW Enhancement

We point out that the length scale associated with the MSW effect is the radius of the Earth. Therefore to verify matter enhancement of neutrino oscillations, it will be necessary to study neutrinos passing through the Earth. For the parameters of MSW solutions to the solar neutrino problem, the only detectable effects occur in a narrow band of energies from 5 to 10 MeV. We propose that serious consideration be given to mounting an experiment at a location within 9.5 degrees of the equator.

hep-ph↗
arXiv1996

Relations between the SNO and the Super Kamiokande solar neutrino rates

By comparing the neutrino spectra measured by SNO and Super Kamiokande, we obtain inequalities between the ratios of observed rate to SSM rate for the two experiments. These inequalities apply to a possibly energy-dependent reduction of the SSM flux and to the case of neutrino oscillations. We use them to examine the relationship between the two experiments expected for the MSW and ``Just-So" oscillation scenarios.

hep-ph↗
arXiv1992

Double Beta Decay

I review the subject of double beta decay with emphasis upon its implications for the neutrino. It is shown that even if right-handed currents provide the phenomenological mechanism for no-neutrino decay, the fundamental mechanism underlying the process must be neutrino mass. Estimates of the mass required suggest that this mechanism is less likely than the direct mechanism of Majorana mass terms in the mass matrix.

hep-ph↗
arXiv1992

MSW Implications of Solar Neutrino Experiments

I discuss the implications for future solar neutrino experiments of the most recent gallium data in the context of the MSW mechanism. At the low energy end of the solar neutrino spectrum we need to measure the $^7$Be component directly; and at the high energy end, we need precise measurements of the shape of the spectrum.

hep-ph↗
arXiv1992

Nonet Symmetry and Two-Body Decays of Charmed Mesons

The decay of charmed mesons into pseudoscalar (P) and vector (V) mesons is studied in the context of nonet symmetry. We have found that it is badly broken in the PP channels and in the P sector of the PV channels as expected from the non-ideal mixing of the ηand the η'. In the VV channels, it is also found that nonet symmetry does not describe the data well. We have found that this discrepancy cannot be attributed entirely to SU(3) breaking at the usual level of 20--30%. At least one, or both, of nonet and SU(3) symmetry must be very badly broken. The possibility of resolving the problem in the future is also discussed.

hep-ph↗
arXiv1992

Implications of New Gallex Results for the MSW Solution of the Solar Neutrino Problem

We compare the implications for 7Be and pp neutrinos of the two MSW fits to the new GALLEX solar neutrino measurements . Small mixing angle solutions tend to suppress the former as electron-neutrinos, but not the latter, and large angle solutions tend to reduce both by about a factor of 2. The consequences for BOREXINO and similar solar neutrino--electron scattering experiments are discussed.

hep-ph↗