Bounding elastic photon-photon scattering at $\sqrt s \approx 1\,$MeV using a laser-plasma platform

Autor: Watt, R., Kettle, B., Gerstmayr, E., King, B., Alejo, A., Astbury, S., Baird, C., Bohlen, S., Campbell, M., Colgan, C., Dannheim, D., Gregory, C., Harsh, H., Hatfield, P., Hinojosa, J., Hollatz, D., Katzir, Y., Morton, J., Murphy, C. D., Nurnberg, A., Osterhoff, J., Pérez-Callejo, G., Põder, K., Rajeev, P. P., Roedel, C., Roeder, F., Salgado, F. C., Samarin, G. M., Sarri, G., Seidel, A., Spindloe, C., Steinke, S., Streeter, M. J. V., Thomas, A. G. R., Underwood, C., Wu, W., Zepf, M., Rose, S. J., Mangles, S. P. D.
Rok vydání: 2024
Předmět:
Druh dokumentu: Working Paper
Popis: We report on a direct search for elastic photon-photon scattering using x-ray and $\gamma$ photons from a laser-plasma based experiment. A gamma photon beam produced by a laser wakefield accelerator provided a broadband gamma spectrum extending to above $E_\gamma = 200$ MeV. These were collided with a dense x-ray field produced by the emission from a laser heated germanium foil at $E_x \approx 1.4$ keV, corresponding to an invariant mass of $\sqrt{s} = 1.22 \pm 0.22$ MeV. In these asymmetric collisions elastic scattering removes one x-ray and one high-energy $\gamma$ photon and outputs two lower energy $\gamma$ photons. No changes in the $\gamma$ photon spectrum were observed as a result of the collisions allowing us to place a 95% upper bound on the cross section of $1.5 \times 10^{15}\,\mu$b. Although far from the QED prediction, this represents the lowest upper limit obtained so far for $\sqrt{s} \lesssim 1$ MeV.
Comment: 6 pages, 10 figures
Databáze: arXiv