Enhancement of nonlinear pair production in a flying-focus pulse

@misc{rahman2026enhancement,
  title = {{Enhancement of nonlinear pair production in a flying-focus pulse}},
  author = {Md Reshad Ur Rahman and Martin S. Formanek and Elias Gerstmayr and Dillon Ramsey and John P. Palastro and Antonino Di Piazza},
  howpublished = {arXiv},
  year = {2026},
  month = aug,
  doi = {10.48550/arxiv.2608.26313},
  eprint = {2608.26313},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2608.26313},
  note = {CC BY 4.0},
}

TY  - UNPB
TI  - Enhancement of nonlinear pair production in a flying-focus pulse
AU  - Md Reshad Ur Rahman
AU  - Martin S. Formanek
AU  - Elias Gerstmayr
AU  - Dillon Ramsey
AU  - John P. Palastro
AU  - Antonino Di Piazza
PY  - 2026
DA  - 2026/08/28
PB  - arXiv
DO  - 10.48550/arxiv.2608.26313
UR  - https://arxiv.org/abs/2608.26313
AB  - A photon can decay into an electron-positron pair in the presence of an intense laser pulse by a process known as nonlinear Breit-Wheeler pair production (NBWPP). For a sufficiently intense pulse, the probability of NBWPP for a high-energy gamma photon scales more favorably with the interaction time than with the field intensity. In contrast to typical stationary-focus Gaussian (SFG) laser pulses, a flying-focus (FF) pulse features a focal point that moves at a programmable velocity. Here, we show that a FF pulse counterpropagating with a high-energy photon beam while its focus copropagates with the beam at the speed of light enhances the NBWPP yield relative to an equal-energy SFG pulse. Numerical simulations show that a Joule-class tightly-focused FF pulse allows for an enhancement of the pair-production yield by 12\%, 29\% and 76\% for a photon of 10, 20 and 50 GeV energy, respectively. Thus, in this regime, FF pulses are more efficient at producing electron-positron pairs than conventional SFG pulses.
ER  -