Quasi-real electron method in high energy quantum electrodynamics

In evolved supernova remnants (SNRs) interacting with molecular clouds, such as IC 443, W44, and 3C391, a highly inhomogeneous structure consisting of a forward shock of moderate Mach number, a cooling layer, a dense radiative shell and an interior region filled with hot tenuous plasma is expected. We present a kinetic model of nonthermal electron injection, acceleration and propagation in that environment and find that these SNRs are efficient electron accelerators and sources of hard X- and gamma-ray emission. The energy spectrum of the nonthermal electrons is shaped by the joint action of first and second order Fermi acceleration in a turbulent plasma with substantial Coulomb losses. Bremsstrahlung, synchrotron, and inverse Compton radiation of the nonthermal electrons produce multiwavelength photon spectra in quantitative agreement with the radio and the hard emission observed by ASCA and EGRET from IC 443. We distinguish interclump shock wave emission from molecular clump shock wave emission accounting for a complex structure of molecular cloud. Spatially resolved X- and gamma- ray spectra from the supernova remnants IC 443, W44, and 3C391 as might be observed with BeppoSAX, Chandra XRO, XMM, INTEGRAL and GLAST would distinguish the contribution of the energetic lepton component to the gamma-rays observed by EGRET.Comment: 14 pages, 4 figure, Astrophysical Journal, v.538, 2000 (in press

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“…In the relativistic limit, we used approximate formulae given by Baier et al (1967) with a correction factor from Baring et al (1999)…”

Section: Appendix Appendix A: Radiative Processesmentioning

confidence: 99%

Nonthermal Emission from a Supernova Remnant in a Molecular Cloud

Bykov

Chevalier

Ellison

et al. 2000

ApJ

174

160

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“…The compact form (3) for the fusion cross section has been derived using the elegant method of invariant tensor integration [17]. This method however cannot be applied any more to calculate the interference term between W W fusion and Higgs-strahlung.…”

mentioning

confidence: 99%

Higgs-strahlung and WW fusion in e+e− collisions

1996

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Higgs-strahlung e + e − → ZH and W W fusion e + e − →ν e ν e H are the most important mechanisms for the production of Higgs bosons in e + e − collisions at LEP2 and future e + e − linear colliders. We have calculated the cross sections and energy/angular distributions of the Higgs boson for these production mechanisms. When the Z boson decays into (electron-)neutrinos, the two production amplitudes interfere. In the cross-over region between the two mechanisms the interference term is positive and of the same size as the individual cross sections, thus enhancing the production rate.

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“…They computed the total cross section [4] and various differential distributions [5]. Similar results were obtained by a number of Russian authors [6]. With the possibility of actually measuring the process (1) at small or zero angle, these analytic, totally inclusive, results are no longer adequate, and the use of approximate matrix elements somewhat doubtful.…”

Section: Long Write-up 1 Introductionmentioning

confidence: 67%

BBBREM — Monte Carlo simulation of radiative Bhabha scattering in the very forward direction

Kleiss

Burkhardt

1994

Computer Physics Communications

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A fast and simple Monte Carlo program is presented that simulates single Bremsstrahlung in Bhabha scattering, e + e − → e + e − γ, without constraints on scattering angles. This allows the study of this process at arbitrarily small, or even vanishing, scattering angles. Experimental cuts can be imposed on an event-by-event basis, allowing for detailed studies of the process as a limitation to beam lifetimes, or a luminosity-measuring device, in e + e − storage rings. As an application, we show that the easy introduction of a cutoff parameter, corresponding to the characteristic distance between particles in the e ± bunches, gives a reduced cross section that is in good agreement with observation. Computers: systems supporting standard FORTRAN 77 Programming language used: FORTRAN 77 Memory required: about 200kb number of bits per word: 32 Subprograms used: none Number of lines in distributed program: 386Nature of physical problem: Radiative Bhabha scattering, e + e − → e + e − γ, has a very large cross section at small scattering angles, and plays various rôles in existing and future e + e − colliders. It can be an important background to several two-photon scattering processes; it forms the major ingredient in the finite lifetime of colliding beams; and it is a possible process by which the luminosity can be measured, by observing electrons or photons emerging at zero scattering angle. Accurate knowledge of its cross section is therefore important. Method of solution:Due to the extremely singular structure of the matrix elements, and the possibility of complicated or unusual experimental cuts, a straightforward integration of the cross section over the allowed phase space is impractical. We therefore construct a Monte Carlo algorithm that generates (random) events in phase space, with a distribution that matches the actual

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Quasi-real electron method in high energy quantum electrodynamics

Cited by 5 publications

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Nonthermal Emission from a Supernova Remnant in a Molecular Cloud

Nonthermal Emission from a Supernova Remnant in a Molecular Cloud

Higgs-strahlung and WW fusion in e+e− collisions

BBBREM — Monte Carlo simulation of radiative Bhabha scattering in the very forward direction

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