arXiv subjects

E. Kh. Akhmedov

Publications and source records attributed to E. Kh. Akhmedov.

45 records · Page 3Linked to original sources

arXiv1996

Resonant neutrino spin-flavor precession and supernova shock revival

A new mechanism of supernova shock revival is proposed, which involves resonant spin--flavor precession of neutrinos with a transition magnetic moment in the magnetic field of the supernova. The mechanism can be operative in supernovae for transition magnetic moments as small as $10^{-14}μ_B$ provided the neutrino mass squared difference is in the range $Δm^2 \sim (3 \;{\rm eV})^2-(600 \;{\rm eV})^2$. It is shown that this mechanism can increase the neutrino--induced shock reheating energy by about 60\%.

hep-ph↗

arXiv1995

A Dynamical Left--Right Symmetry Breaking Model

Left--right symmetry breaking in a model with composite Higgs scalars is discussed. It is assumed that the low--energy degrees of freedom are just fermions and gauge bosons and that the Higgs bosons are generated dynamically through a set of gauge-- and parity--invariant 4-fermion operators. It is shown that in a model with composite bi-doublet and two triplet scalars there is no parity breaking at low energies, whereas in the model with two doublets instead of two triplets parity is broken automatically regardless of the choice of the parameters of the model. For phenomenologically allowed values of the right--handed scale the tumbling symmetry breaking mechanism is realized in which parity breaking at a high scale $μ_R$ propagates down and eventually causes the \EW symmetry breaking at the scale $μ_{EW}\sim 100$ GeV. The model exhibits a number of low and intermediate mass Higgs bosons with certain relations between their masses. In particular, the $SU(2)_L$ Higgs doublet $χ_L$ is a pseudo--Goldstone boson of the accidental (approximate) $SU(4)$ symmetry of the Higgs potential and therefore is expected to be relatively light.

hep-ph↗

arXiv1994

Solar Neutrino Data, Neutrino Magnetic Moments and Flavor Mixing

The results of all currently operating solar neutrino experiments are analyzed in the framework of the resonant neutrino spin--flavor precession scenario including the effects of neutrino mixing. Nine different profiles of the solar magnetic field are used in the calculations. It is shown that the available experimental data can be accounted for within the considered scenario. The Ga--Ge data lead to an upper limit on the neutrino mixing angle: $\sin 2θ_0 \aprle 0.25$. One can discriminate between small mixing angle ($\sin 2θ_0 \aprle 0.1$) and moderate mixing angle solutions by studying the solar $\barν_{e}$ flux which is predicted to be sizeable for moderate mixing angles. The expected signals due to $\barν_{e}$ in the SNO, Super--Kamiokande and Borexino experiments are calculated and found to be detectable for $\sin 2θ_0 \aprge 0.1$.

hep-ph↗

arXiv1994

Neutrino Magnetic Moments and the Solar Neutrino Problem

Present status of the neutrino magnetic moment solutions of the solar neutrino problem is reviewed. In particular, we discuss a possibility of reconciling different degrees of suppression and time variation of the signal (or lack of such a variation) observed in different solar neutrino experiments. It is shown that the resonant spin--flavor precession of neutrinos due to the interaction of their transitions magnetic moments with solar magnetic field can account for all the available solar neutrino data. For not too small neutrino mixing angles ($\sin 2θ_0 \aprge 0.2$) the combined effect of the resonant spin--flavor precession and neutrino oscillations can result in an observable flux of solar $\barν_{e}$'s.

hep-ph↗

arXiv1994

Atmospheric Neutrinos

Recent results of atmospheric neutrino experiments are reviewed and their possible interpretations are discussed, main emphasis being put on the neutrino oscillation hypothesis.

hep-ph↗

arXiv1993

Pontecorvo's Original Oscillations Revisited

We show that a left-handed neutrino $ν_L$ can oscillate into its $CP$- conjugated state $\barν_R$ with maximal amplitude, in direct analogy with $K^0-\bar{K}^0$ oscillations. Peculiarities of such oscillations under different conditions are studied.

hep-ph↗

arXiv1993

Implications of Gallium Solar Neutrino Data for the Resonant Spin-Flavor Precession Scenario

We consider the implications of the recent results of SAGE and GALLEX experiments for the solution of the solar neutrino problem in the framework of the resonant neutrino spin-flavor precession scenario. It is shown that this scenario is consistent with all the existing solar neutrino data including the gallium results. The quality of the fit of the data depends crucially on the magnetic field profile used which makes it possible to get information about the magnetic field in the solar interior. In particular, the magnetic field in the core of the sun must not be too strong ($<3 \times 10^6$ G). The detection rate in the gallium detectors turns out to be especially sensitive to the magnitude of $Δm^2$. Predictions for forthcoming solar-neutrino experiments are made.

hep-ph↗

arXiv1993

Neutrinos with Mixing in Twisting Magnetic Fields

Transitions in a system of neutrinos with vacuum mixing and magnetic moments, propagating in matter and transverse magnetic field, are considered. It is shown that in the realistic case of magnetic field direction varying along the neutrino path qualitatively new phenomena become possible: permutation of neutrino conversion resonances, appearance of resonances in the neutrino-antineutrino ($ν_{lL}\leftrightarrow\barν_{lR}$) transition channels, neutrino-antineutrino resonant conversion, large amplitude $ν_{lL}\leftrightarrow\barν_{lR}$ oscillations, merging of different resonances (triple resonances). Possible phenomenological implications of these effects are briefly discussed.

hep-ph↗

arXiv1992

Planck Scale Effects on the Majoron

The hypothesis that non-perturbative gravitational effects lead to explicit breaking of global symmetries is considered in the context of Majoron models. We find that the nonvanishing Majoron mass generated by these effects can overclose the universe unless the massive Majoron is unstable. The cosmological mass density constraints can then be satisfied only if $V_{BL} < 10$ TeV, where $V_{BL}$ is the scale of $B-L$ symmetry breaking.

hep-ph↗