Neutrino oscillations in dense neutrino gases

Samuel, Stuart

doi:10.1103/physrevd.48.1462

Cited by 184 publications

(256 citation statements)

References 12 publications

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“…Our results for these corrections agree with previous calculations [14,15], using completely different techniques. These corrections give a nondiagonal term in the effective mass matrix.…”

Section: Propagation Modes Of the Neutrinossupporting

confidence: 82%

Equilibrium properties of self-interacting neutrinos in the quasi-particle approach

Sirera¹,

Perez²

2004

J. Phys. G: Nucl. Part. Phys.

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In this work a neutrino gas in equilibrium is studied both at T = 0 and at finite temperature.Neutrinos are treated as massive Dirac quasi-particles with two generations. We include selfinteractions among the neutrinos via neutral currents, as well as the interaction with a background of matter. To obtain the equilibrium properties we use Wigner function techniques. To account for corrections beyond the Hartree approximation, we also introduce correlation functions. We prove that, under the quasi-particle approximation, these correlation functions can be expressed as products of Wigner functions. We analyze the main properties of the neutrino eigenmodes in the medium, such as effective masses and mixing angle. We show that the formulae describing these quantities will differ with respect to the case with no self-interactions.

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“…Our results for these corrections agree with previous calculations [14,15], using completely different techniques. These corrections give a nondiagonal term in the effective mass matrix.…”

Section: Propagation Modes Of the Neutrinossupporting

confidence: 82%

Equilibrium properties of self-interacting neutrinos in the quasi-particle approach

Sirera¹,

Perez²

2004

J. Phys. G: Nucl. Part. Phys.

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“…On the time scale of a few bipolar oscillation periods, the two components essentially equipartition, although asymptotically a small offset remains that depends on ω/µ. Moreover, the neutrino-neutrino energy ("kinetic energy") now develops a nonvanishing flux term E 1 = −µD 2 1 /4 that inevitably is negative. The normal hierarchy (left) is initially similar in that E ω and E µ oscillate as for a pendulum, even though this motion is not visible on the scale of the plot.…”

Section: B Half-isotropic Casementioning

confidence: 99%

“…Therefore, if the energy spectrum is broad, the energy dependence of the oscillation frequency quickly leads to kinematical decoherence, i.e., along a neutrino beam the overall flavor content quickly approaches an average value. The situation changes radically when neutrinos themselves provide a significant refractive effect, leading to collective oscillation modes [1,2,3,4,5,6,7,8,9,10,11,12] that can be of practical interest in the early universe [13,14,15,16] or in core-collapse supernovae [17,18,19,20,21,22,23,24,25,26]. Defining the parameter…”

Section: Introductionmentioning

confidence: 99%

Self-induced decoherence in dense neutrino gases

2007

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Dense neutrino gases exhibit collective oscillations where "self-maintained coherence" is a characteristic feature, i.e., neutrinos of different energies oscillate with the same frequency. In a nonisotropic gas, however, the flux term of the neutrino-neutrino interaction has the opposite effect of causing kinematical decoherence of neutrinos propagating in different directions, an effect that is at the origin of the "multi-angle behavior" of neutrinos streaming off a supernova core. We cast the equations of motion in a form where the role of the flux term is manifest. We study in detail the symmetric case of equal neutrino and antineutrino densities where the evolution consists of collective pair conversions ("bipolar oscillations"). A gas of this sort is unstable in that an infinitesimal anisotropy is enough to trigger a run-away towards flavor equipartition. The "self-maintained coherence" of a perfectly isotropic gas gives way to "self-induced decoherence."

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“…Because of neutrino-neutrino forward scattering or neutrino self-interaction [1,2,3] neutrinos can experience collective flavour transformation in environments such as the early Universe (e.g., [4,5,6,7,8,9]) and supernovae (e.g., [10,11,12,13]) where neutrino number densities can be very large. This phenomenon is different from the conventional Mikheyev-Smirnov-Wolfenstein (MSW) effect [14,15] in that the flavour evolution histories of neutrinos in collective oscillations are coupled together and must be solved simultaneously.…”

Section: Introductionmentioning

confidence: 99%

Symmetries in collective neutrino oscillations

Duan¹,

Fuller²,

Qian³

2009

J. Phys. G: Nucl. Part. Phys.

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Abstract. We discuss the relationship between a symmetry in the neutrino flavour evolution equations and neutrino flavour oscillations in the collective precession mode. This collective precession mode can give rise to spectral swaps (splits) when conditions can be approximated as homogeneous and isotropic. Multi-angle numerical simulations of supernova neutrino flavour transformation show that when this approximation breaks down, non-collective neutrino oscillation modes decohere kinematically, but the collective precession mode still is expected to stand out. We provide a criterion for significant flavour transformation to occur if neutrinos participate in a collective precession mode. This criterion can be used to understand the suppression of collective neutrino oscillations in anisotropic environments in the presence of a high matter density. This criterion is also useful in understanding the breakdown of the collective precession mode when neutrino densities are small.

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Neutrino oscillations in dense neutrino gases

Cited by 184 publications

References 12 publications

Equilibrium properties of self-interacting neutrinos in the quasi-particle approach

Equilibrium properties of self-interacting neutrinos in the quasi-particle approach

Self-induced decoherence in dense neutrino gases

Symmetries in collective neutrino oscillations

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