Electron-positron pair production by collisions of non-relativistic charged particles

Nikolaus, B. A.; Fengler, H.; Manakos, P.

doi:10.1007/bf01412013

Cited by 3 publications

(7 citation statements)

References 7 publications

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“…We have noticed that an important contribution (connected with gauge invariance) had been neglected in previous analyses of this process [1~], although the correct differential cross section is already given in the book of Landau and Lifshitz [9]. However, the correct gauge invariant lowest order cross section did not agree with the experimental data [5]: The theoretical prediction overestimates'the pair production yield. In order to analyze the reasons for this disagreement we included non perturbative effects (i.e.…”

Section: Introductionmentioning

confidence: 72%

“…which in perturbative calculation gives the dominant contribution [5]. ~(r) and 7Js(r ) are non relativistic Coulomb wave functions.…”

Section: Nonperturbative Treatment Of the Projectilementioning

confidence: 99%

“…T is the kinetic energy in the center of mass system. The corresponding expression for the cross section [5] is (8) where/~ is the reduced mass and…”

Section: The General Formalismmentioning

confidence: 99%

“…The transition amplitude for electron positron pair production can be written in the following way [5]:…”

Section: The General Formalismmentioning

confidence: 99%

“…Discrepancies between experimental results [2,3] and the calculation of Heitler and Nordheim appeared. For this reason we had repeated the calculation [5]. We have noticed that an important contribution (connected with gauge invariance) had been neglected in previous analyses of this process [1~], although the correct differential cross section is already given in the book of Landau and Lifshitz [9].…”

Section: Introductionmentioning

confidence: 98%

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Coulomb distortion effects in electron positron pair production near threshold

Nikolaus

Manakos

1988

Z. Physik A - Atomic Nuclei

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Section: Introductionmentioning

confidence: 72%

“…which in perturbative calculation gives the dominant contribution [5]. ~(r) and 7Js(r ) are non relativistic Coulomb wave functions.…”

Section: Nonperturbative Treatment Of the Projectilementioning

confidence: 99%

“…T is the kinetic energy in the center of mass system. The corresponding expression for the cross section [5] is (8) where/~ is the reduced mass and…”

Section: The General Formalismmentioning

confidence: 99%

“…The transition amplitude for electron positron pair production can be written in the following way [5]:…”

Section: The General Formalismmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

See 3 more Smart Citations

Coulomb distortion effects in electron positron pair production near threshold

Nikolaus

Manakos

1988

Z. Physik A - Atomic Nuclei

Self Cite

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Star formation, metallicity and dust properties derived from the StromloAPM galaxy survey spectra

Charlot

Kauffmann

Longhetti

et al. 2002

Monthly Notices of the Royal Astronomical Society

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A B S T R A C TWe have derived star formation rates (SFRs), gas-phase oxygen abundances and effective dust absorption optical depths for a sample of galaxies drawn from the Stromlo-APM redshift survey using the new model of Charlot & Longhetti (CLO1), which provides a physically consistent description of the effects of stars, gas and dust on the integrated spectra of galaxies. Our sample consists of 705 galaxies with measurements of the fluxes and equivalent widths of Ha, [O II] and one or both of [N II] and [S II]. For a subset of the galaxies, 60-and 100-mm IRAS fluxes are available. We compare the star formation rates derived using the model with those derived using standard estimators based on the Ha, the [O II] and the far-infrared luminosities of the galaxies. The CL01 SFR estimates agree well with those derived from the IRAS fluxes, but are typically a factor of ,3 higher than those derived from the Ha or the [O II] fluxes, even after the usual mean attenuation correction of A Ha ¼ 1 mag is applied to the data. We show that the reason for this discrepancy is that the standard Ha estimator neglects the absorption of ionizing photons by dust in H II regions and the contamination of Ha emission by stellar absorption. We also use our sample to study variations in star formation and metallicity as a function of galaxy absolute b J magnitude. For this sample, the star formation rate per unit b J luminosity is independent of magnitude. The gas-phase oxygen abundance does increase with b J luminosity, although the scatter in metallicity at fixed magnitude is large.

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γ-rays and the far-infrared–radio continuum correlation reveal a powerful Galactic Centre wind

Crocker

Jones

Aharonian

et al. 2011

Monthly Notices of the Royal Astronomical Society: Letters

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We consider the thermal and non-thermal emission from the inner 200 pc of the Galaxy. The radiation from this almost starburst-like region is ultimately driven dominantly by ongoing massive star formation. We show that this region's radio continuum (RC) emission is in relative deficit with respect to the expectation afforded by the far-infrared-radio continuum correlation (FRC). Likewise we show that the region's γ -ray emission falls short of that expected given its star formation and resultant supernova rates. These facts are compellingly explained by positing that a powerful (400-1200 km s −1 ) wind is launched from the region. This wind probably plays a number of important roles including advecting positrons into the Galactic bulge thus explaining the observed ∼kpc extension of the 511 keV positron annihilation signal around the GC. We also show that the large-scale GC magnetic field falls in the range ∼100-300 µG and that -in the time they remain in the region -GC cosmic rays do not penetrate into the region's densest molecular material.

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Electron-positron pair production by collisions of non-relativistic charged particles

Cited by 3 publications

References 7 publications

Coulomb distortion effects in electron positron pair production near threshold

Coulomb distortion effects in electron positron pair production near threshold

Star formation, metallicity and dust properties derived from the StromloAPM galaxy survey spectra

γ-rays and the far-infrared–radio continuum correlation reveal a powerful Galactic Centre wind

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