Laser-Assisted Positron-Impact Ionization of Hydrogen Atoms

Abstract

The theory of triple differential cross-sections, developed previously within the framework of nonrelativistic Schrödinger formalism, is extended to the relativistic treatment by using the Dirac-Volkov formalism. At high energies, the colliding particles lose their Coulomb character and the channel of the symmetric coplanar geometry is opened. In the first Born approximation, we have studied theoretically the laser-assisted relativistic ionization of hydrogen atoms by positron impact in this geometry. Triple differential cross-sections are calculated by using two approaches: (i) RPWSG to describe relativistic plane wave in the symmetric geometry, (ii) DVPWSG (Dirac-Volkov plane wave in the symmetric geometry) in which we take full account of the relativistic dressing effects, has been proposed to study the influence of laser field on the colliding particles. To check the consistency of our model, we have used, for comparison, the nonrelativistic approach: nonrelativistic plane wave in the symmetric geometry. Numerical results for the variation of relativistic triple differential cross-sections and their dependences on laser field parameters (intensity, frequency) and incident positron energy are also presented. As for the laser modifications, by summing over a very large number of exchanged photons, the laser-assisted triple differential cross-sections usually tends to approach the laser-free triple differential cross-sections, obeying the famous Kroll-Watson sum rule for positron projectile. In the absence, of any experimental data at high energies for this particular ionization process, we are not in a position to compare the present results with the experimental findings.

Two-body hadronic decay of K+ in the presence of a circularly polarized laser field

“…Today, the technological progress gives us the opportunity to introduce an external electromagnetic field in high-energy physics interactions. Indeed, several studies have been made to study the impact of the laser field on the decay width [10][11][12][13][14] and on the effective crosssection [9,[15][16][17] by introducing the phenomenon of emission and/or absorption of photons [18]. For instance, (a) E-mail: b.manaut@usms.ma (corresponding author) in [19,20], the authors illustrated the effect of an electromagnetic field with circular polarization on the decay widths and lifetime of the charged pion and the Z boson.…”

Effect of electron spin polarization in laser-assisted electron-proton scattering

“…In view of the new developments in laser technology, high intensity and short duration laser pulses are generated nowadays in the laboratory [1][2][3]. This has greatly inspired researchers to study various ultrafast processes in the presence of strong laser fields, such as atomic processes [4][5][6][7][8][9][10] and those that occur in the frameworks of quantum electrodynamics (QED) [11][12][13][14][15] and electroweak theory [16][17][18][19][20][21], as well as recently the processes of Higgs boson production beyond the Standard Model [22][23][24]. New experimental perspectives for the study of these processes in the presence of laser field are proposed by future high field laboratories, such as the Extreme Light Infrastructure (ELI) [25] and the Exawatt Center for Extreme Light Studies (XCELS) [26].…”