Pair creation in collision of $\gamma$-ray beams produced with high-intensity lasers

Direct production of electron-positron pairs in two-photon collisions, the Breit-Wheeler process, is one of the basic processes in the universe. However, it has never been directly observed in the laboratory because of the absence of the intense $\gamma$-ray sources. Laser-induced synchrotron sources emission may open a way to observe this process. The feasibility of an experimental setup using a MeV photon source is studied in this paper. We compare several $\gamma$-ray sources and estimate the expected number of electron-positron pairs and competing processes by using numerical simulations including quantum electrodynamic effects.

Figure 1

Cross section ${\sigma }_{\gamma \gamma }$ versus $E_{{\gamma }_1}$ and $E_{{\gamma }_1}$ near the threshold for $\varphi =\pi$.

Figure 2

Probability of BW pair creation per unit of length versus the incident photon energy $E_{\gamma }$ for the thermal bath temperature, 100 (solid), 250 (dashed), and 400 eV (dash-dotted).

Figure 3

Experimental setup for the Breit-Wheeler pairs production with MeV colliding photon beams.

Figure 4

Spectral and angular distribution of the emitted photon energy in the interaction of a laser pulse at ${10}^{23}$ $\mathrm{W}/{\mathrm{cm}}^2$ with an 8 $\mu \mathrm{m}$ aluminium target.

Figure 5

Spectral and angular distribution of the emitted photon energy in the interaction of a laser pulse at ${10}^{23}$ $\mathrm{W}/{\mathrm{cm}}^2$, in the case of gas target, $n_e=4n_c,80\mu \mathrm{m}$.