We study the neutrino-photon processes such as $gammagammato ubar{ u}$ and $ ugammato ugamma$ in a background magnetic field smaller than the critical magnetic field $B_cequiv m_e^2/e$. Using Schwingers proper-time method, we extract leading magnetic-field contributions to the above processes. Our result is valid throughout the kinematic regime where both neutrino and photon energies are significantly smaller than $m_W$. We briefly discuss the astrophysical implications of our result.
The weak-field expansion of the charged fermion propagator under a uniform magnetic field is studied. Starting from Schwingers proper-time representation, we express the charged fermion propagator as an infinite series corresponding to different Landau levels. This infinite series is then reorganized according to the powers of the external field strength $B$. For illustration, we apply this expansion to $gammato ubar{ u}$ and $ uto ugamma$ decays, which involve charged fermions in the internal loop. The leading and subleading magnetic-field effects to the above processes are computed.
We examine the analytic properties of the photon polarization function in a background magnetic field, using the technique of inverse Mellin transform. The photon polarization function is first expressed as a power series of the photon energy $omega$ with $omega< 2m_e$. Based upon this energy expansion and the branch cut of the photon polarization function in the complex $omega$ plane, we compute the absorptive part of the polarization function with the inverse Mellin transform. Our results are valid for arbitrary photon energies and magnetic-field strengths. The applications of our approach are briefly discussed.
We develop the technique of inverse Mellin transform for processes occurring in a background magnetic field. We show by analyticity that the energy (momentum) derivatives of a field theory amplitude at the zero energy (momentum) is equal to the Mellin transform of the absorptive part of the amplitude. By inverting the transform, the absorptive part of the amplitude can be easily calculated. We apply this technique to calculate the photon polarization function in a background magnetic field.
Using holography, we analyse deep inelastic scattering of a flavor current from a strongly coupled quark-gluon plasma with a background magnetic field. The aim is to show how the magnetic field affects the partonic picture of the plasma. The flavored constituents of the plasma are described using D3-D7 brane model at finite temperature. We find that the presence of a background magnetic field makes it harder to detect the plasma constituents. Our calculations are in agreement with those calculated from other approaches. Besides the resulting changes for plasma structure functions a criteria will be obtained for the possibility of deep inelastic process in the presence of magnetic field.
The processes of neutrino production of electron-positron pairs, $ u bar u to e^- e^+$ and $ u to u e^- e^+$, in a magnetic field of arbitrary strength, where electrons and positrons can be created in the states corresponding to excited Landau levels, are analysed. The results can be applied for calculating the efficiency of the electron-positron plasma production by neutrinos in the conditions of the Kerr black hole accretion disc considered by experts as the most possible source of a short cosmological gamma burst.
Tzuu-Kang Chyi
,Chien-Wen Hwang
,W. F. Kao
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(1999)
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"Neutrino-photon scattering and its crossed processes in a background magnetic field"
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Jie Jun Tseng
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