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arXiv · 2109.00555

Pulse envelope effects in nonlinear Breit-Wheeler pair-creation

S. Tang·B. King
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Abstract

The effect of the pulse envelope on electron-positron pair creation in a circularly-polarised laser pulse is investigated. Interference on the length scale of the pulse envelope, and smoothness of the pulse edges are found to influence the pair spectrum. A toy model of a flat-top pulse is used to identify pulse envelope effects inaccessible to local approaches. Broadening of channel openings and a widening of the energy and transverse momentum distribution of the pair are found to receive contributions that are below the local harmonic threshold. By comparing pair yields in a flat-top, sine-squared and Gaussian pulse, a link between pulse shape and photon-polarised Breit-Wheeler is found. In the transverse momentum distribution, a signal of pulse envelope interference is found in an azimuthal asymmetry, which appears in intense fields and persists in long pulses.

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S. Tang, B. King. 2021-09-01. Pulse envelope effects in nonlinear Breit-Wheeler pair-creation. https://doi.org/10.1103/physrevd.104.096019

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