arXiv subjects

T. I. Rashba

Publications and source records attributed to T. I. Rashba.

24 records · Page 2Linked to original sources

arXiv2003

Large mixing angle oscillations as a probe of the deep solar interior

We re-examine the sensitivity of solar neutrino oscillations to noise in the solar interior using the best current estimates of neutrino properties. Our results show that the measurement of neutrino properties at KamLAND provides new information about fluctuations in the solar environment on scales to which standard helioseismic constraints are largely insensitive. We also show how the determination of neutrino oscillation parameters from a combined fit of KamLAND and solar data depends strongly on the magnitude of solar density fluctuations. We argue that a resonance between helioseismic and Alfven waves might provide a physical mechanism for generating these fluctuations and, if so, neutrino-oscillation measurements could be used to constrain the size of magnetic fields deep within the solar radiative zone.

hep-ph↗

arXiv2001

A non-resonant dark-side solution to the solar neutrino problem

We re-analyse spin-flavour precession solutions to the solar neutrino problem in the light of the recent SNO CC result as well as the 1258--day Super-Kamiokande data and the upper limit on solar anti-neutrinos. In a self-consistent magneto-hydrodynamics approach the resulting scheme has only 3 effective parameters: $Δm^2$, $μB_\perp$ and the neutrino mixing angle $θ$. We show how a rates-only analysis for fixed $μB_\perp$ slightly favours spin-flavour precession (SFP) solutions over oscillations (OSC). In addition to the resonant solution (RSFP for short), there is a new non-resonant solution (NRSFP) in the ``dark-side''. Both RSFP and NRSFP lead to flat recoil energy spectra in excellent agreement with the latest SuperKamiokande data. We also show that in the presence of a neutrino transition magnetic moment of $10^{-11}$ Bohr magneton, a magnetic field of 80 KGauss eliminates all large mixing solutions other than the so-called LMA solution.

hep-ph↗

arXiv2001

Solar neutrino problem accounting for self-consistent magnetohydrodynamics solution for solar magnetic fields

The analysis of the resonant spin-flavour (RSF) solutions to the solar neutrino problem in the framework of simplest analytic solutions to the solar magneto-hydrodynamics (MHD) equations is presented. We performed the global fit of the recent solar neutrino data, including event rates as well as day and night recoil electron spectra induced by solar neutrino interactions in SuperKamiokande. We compare quantitatively our simplest MHD-RSF fit with vacuum oscillation (VAC) and MSW--type (SMA, LMA and LOW) solutions to the solar neutrino problem using a common well-calibrated theoretical calculation and fit procedure and find MHD-RSF fit to be somewhat better than those obtained for the favored neutrino oscillation solutions. We made the predictions for future experiments to disentangle the MHD-RSF scenario from other scenarios.

hep-ph↗

arXiv2000

The Simplest Resonant Spin--Flavour Solution to the Solar Neutrino Problem

We re-analyse the resonant spin-flavour (RSF) solutions to the solar neutrino problem in the framework of analytic solutions to the solar magneto-hydrodynamics (MHD) equations. By substantially eliminating the arbitrariness associated to the magnetic field profile due to both mathematical consistency and physical requirements we propose the simplest scheme (MHD-RSF, for short) for solar neutrino conversion using realistic static MHD solutions. Using such effective two-parameter scheme we perform the first global fit of the recent solar neutrino data, including event rates as well as zenith angle distributions and recoil electron spectra induced by solar neutrino interactions in Superkamiokande. We compare quantitatively our simplest MHD-RSF fit with vacuum oscillation (VAC) and MSW-type (SMA, LMA and LOW) solutions to the solar neutrino problem using a common well-calibrated theoretical calculation and fit procedure. We find our MHD-RSF fit to be somewhat better than those obtained for the favored neutrino oscillation solutions, though not in a statistically significant way. We briefly discuss the prospects to disentangle our MHD-RSF scenario at future solar neutrino experiments, giving some predictions for the SNO experiment.

hep-ph↗

arXiv2000

Neutrino scattering on polarized electron target as a test of neutrino magnetic moment

We suggest to use a polarized electron target for improving the sensitivity of the search for the neutrino magnetic moment to the level $\sim 3\cdot10^{-13}μ_B$ in the processes of neutrino (antineutrino) -- electron scattering. It is shown that in this case the weak interaction term in the total cross section is significantly suppressed comparing with unpolarized case, but the electromagnetic term does not depend on electron polarization.

hep-ph↗

arXiv2000

Resonant Spin-Flavor Precession Solution to the Solar Neutrino Problem and electron antineutrinos from the Sun

We have found allowed squared mass difference, magnetic field, mixing angle - regions for the Resonant Spin-Flavor Precession Solution to the Solar Neutrino Problem fitted with the data of all acting solar neutrino experiments. The typical mass difference region varying in dependence on the mixing angle is allowed for some discrete magnetic field regions in a wide range for the fixed neutrino transition magnetic moment. Except of the first allowed range with the lowest field strength the magnetic field amplitude within other discrete allowed regions depend essentially on the shape of a regular magnetic field profile in the convective zone of the Sun. For the non-zero neutrino mixing one can find at 99.9% C.L. an upper limit on the mixing, originated by the non-observation of electron antineutrinos in the SuperKamiokande detector. This limit occurs also sensitive to the magnetic field profile. While at 67% C.L. there is another more stringent upper limit coming from inconsistency of the gallium experiments with others. A new allowed region appears in the case of an additional assumption that the Homestake data are 1.3 times less than the experimental event rate.

hep-ph↗