Matter Enhanced Neutrino Oscillations with a Realistic Earth Density Profile

We have investigated matter enhanced neutrino oscillations with a mantle-core-mantle step function and a realistic Earth matter density profile in both a two and a three neutrino scenario. We found that the realistic Earth matter density profile can be well approximated with the mantle-core-mantle step function and that there could be an influence on the oscillation channel $\nu_\mu \to \nu_\tau$ due to resonant enhancement of one of the mixing angles.Comment: 8 pages, 5 figures (PostScript), MPLA LaTe

Chizhov and Petcov Reply

We have found in [1] new conditions for a total neutrino conversion in the case of neutrino oscillations taking place in a medium, consisting of n = 2 (or 3) alternating layers with constant densities $N_1$ and $N_2$. It is claimed in [4] that our results are particular case of enhancement of neutrino oscillations, which was suggested earlier by other authors and was widely discussed in the literature. We refute these claims, confirming the novelty of our results.Comment: 2 pages, LATEX; concise (essentially 1 page) and somewhat modified version of Ref. SISSA 5/2000/EP (hep-ph/0003110); reply on the ``Comment on New Conditions for a Total Neutrino Conversion in a Medium'', Phys. Rev. Lett. 85 (2000) 3978; published as ``Chizhov and Petcov Reply'' in Phys. Rev. Lett. 85 (2000) 397

Oscillations of high energy neutrinos in matter: Precise formalism and parametric resonance

We present a formalism for precise description of oscillation phenomena in matter at high energies or high densities, V > \Delta m^2/2E, where V is the matter-induced potential of neutrinos. The accuracy of the approximation is determined by the quantity \sin^2 2\theta_m \Delta V/2\pi V, where \theta_m is the mixing angle in matter and \Delta V is a typical change of the potential over the oscillation length (l \sim 2\pi/V). We derive simple and physically transparent formulas for the oscillation probabilities, which are valid for arbitrary matter density profiles. They can be applied to oscillations of high energy (E > 10 GeV) accelerator, atmospheric and cosmic neutrinos in the matter of the Earth, substantially simplifying numerical calculations and providing an insight into the physics of neutrino oscillations in matter. The effect of parametric enhancement of the oscillations of high energy neutrinos is considered. Future high statistics experiments can provide an unambiguous evidence for this effect.Comment: LaTeX, 5 pages, 1 figure. Linestyles in the figure corrected to match their description in the caption; improved discussion of the accuracy of the results; references added. Results and conclusions unchange

Stimulated Neutrino Transformation with Sinusoidal Density Profiles

Large amplitude oscillations between the states of a quantum system can be stimulated by sinusoidal external potentials with frequencies that are similar to the energy level splitting of the states or a fraction thereof. Situations when the applied frequency is equal to an integer fraction of the energy level splittings are known as parametric resonances. We investigate this effect for neutrinos both analytically and numerically for the case of arbitrary numbers of neutrino flavors. We look for environments where the effect may be observed and find that supernova are the one realistic possibility due to the necessity of both large densities and large amplitude fluctuations. The comparison of numerical and analytic results of neutrino propagation through a model supernova reveals it is possible to predict the locations and strengths of the stimulated transitions that occur.Comment: 14 pages, 6 figure

The MSW effect and Matter Effects in Neutrino Oscillations

The MSW (Mikheyev-Smirnov-Wolfenstein) effect is the adiabatic or partially adiabatic neutrino flavor conversion in medium with varying density. The main notions related to the effect, its dynamics and physical picture are reviewed. The large mixing MSW effect is realized inside the Sun providing the solution of the solar neutrino problem. The small mixing MSW effect driven by the 1-3 mixing can be realized for the supernova (SN) neutrinos. Inside the collapsing stars new elements of the MSW dynamics may show up: the non-oscillatory transition, non-adiabatic conversion, time dependent adiabaticity violation induced by shock waves. Effects of the resonance enhancement and the parametric enhancement of oscillations can be realized for the atmospheric and accelerator neutrinos in the Earth. Precise results for neutrino oscillations in the low density medium with arbitrary density profile are presented and the attenuation effect is described. The area of applications is the solar and SN neutrinos inside the Earth, and the results are crucial for the neutrino oscillation tomography.Comment: 18 pages, latex, 6 figures, talk given at the Nobel Symposium 129, ``Neutrino Physics'', Haga Slott, August 19 - 24, 200

Could One Find Petroleum Using Neutrino Oscillations in Matter?

In neutrino physics, it is now widely believed that neutrino oscillations are influenced by the presence of matter, modifying the energy spectrum produced by a neutrino beam traversing the Earth. Here, we will discuss the reverse problem, i.e. what could be learned about the Earth's interior from a single neutrino baseline energy spectrum, especially about the Earth's mantle. We will use a statistical analysis with a low-energy neutrino beam under very optimistic assumptions. At the end, we will note that it is hard to find petroleum with such a method, though it is not too far away from technical feasibility.Comment: 6 pages, 4 figures, EPL LaTeX. Final version to be published in Europhys. Let

Atmospheric, long baseline, and reactor neutrino data constraints on θ13\theta_{13}

A new atmospheric neutrino oscillation tool which utilizes full three neutrino oscillation probabilities and a full three neutrino treatment of the MSW effect is combined with a standard analysis of the K2K, MINOS, and CHOOZ data to examine the bounds on $\theta_{13}$ implied by existing data, including the recent, more finely binned, Super-K atmospheric data. In the region $L/E_\nu\gtrsim 10^4$ km/GeV, we have previously found that the sub-dominant expansion does not converge and that terms linear in $\theta_{13}$ can be significant. The current analysis confirms this and leads to the conclusion that $\theta_{13}$ is bounded from above by the atmospheric data while CHOOZ provides the lower bound. We trace the origin of this result to fully contained data in the previously mentioned very long baseline region, to a combination of a quadratic in $\theta_{13}$ term in ${\mathcal P}_{ee}$ and a linear term in ${\mathcal P}_{e\mu}$ and their contribution to $R_e$, a broad MSW resonance for the solar mass-squared difference at 180 MeV, and an increase in $\theta_{12}$ due to this resonant matter effect which alters the sign of the linear in $\theta_{13}$ term. Assuming CP is conserved in the lepton sector, we find $\theta_{13}=-0.07^{+0.18}_{-0.11}$, the asymmetry being a reflection of the importance of the linear in $\theta_{13}$ terms.Comment: 4 pages, 5 figures, typos corrected, manuscript shortene

Performance of the AMS-02 Transition Radiation Detector

For cosmic particle spectroscopy on the International Space Station the AMS experiment will be equipped with a Transition Radiation Detector (TRD) to improve particle identification. The TRD has 20 layers of fleece radiator with Xe/CO2 proportional mode straw tube chambers. They are supported in a conically shaped octagon structure made of CFC-Al-honeycomb. For low power consumption VA analog multiplexers are used as front-end readout. A 20 layer prototype built from final design components has achieved proton rejections from 100 to 2000 at 90% electron efficiency for proton beam energies up to 250 GeV with cluster counting, likelihood and neural net selection algorithms.Comment: 11 pages, 25 figures, espcrc2.sty (elsevier 2-column

Floquet theory of neutrino oscillations in the earth

We review the Floquet theory of linear differential equations with periodic coefficients and discuss its applications to neutrino oscillations in matter of periodically varying density. In particular, we consider parametric resonance in neutrino oscillations which can occur in such media, and discuss implications for oscillations of neutrinos traversing the earth and passing through the earth's core.Comment: LaTeX, 28 pages, 8 eps figures. Contribution to the special issue of Yad. Fiz. dedicated to the memory of A.B. Migda