ELFT HÍRADÓ

[Zimányiné Horváth Vera <Vera.Horvath AT eli-alps.hu>]

Előadó:                                Varró Sándor (ELI ALPS, Szeged)
Az előadás címe:              Anomalous nonlinear Compton scattering in the 
X-ray regime

Időpont:                              2024. november 29., 9 óra
Helyszín:                             az ELI ALPS konferenciaterme (Szeged, 
Wolfgang Sandner utca 3.)

Absztrakt:
The nonlinear Compton scattering has been one of the most thoroughly analysed 
strong-field phenomenon, whose study started already immediately after the 
invention of the laser. On the other hand, by now, there have been only few 
direct measurements of high-harmonic generation by free electrons. Recently, 
in a series of  experiments, the second harmonic of X-ray radiation (of 
incoming photon energy around 10 keV) has been observed in Compton scattering 
of a highpower free-electron laser beam (of about 10^21 W/cm^2 intensity) on 
beryllium targets [1-2]. An unexpectedly large (of almost 2 keV) red-shift of 
this component has been easured, in addition to the expected Compton shift. 
This anomaly cannot be explained by assuming the known possible causes like 
the well-known intensity-dependent frequency shift, the quasi-free property 
of the electron, or thermal effects. In the present talk, first we shall 
review the main features of this anomaly and some attempts for its 
interpretation. Then, we outline our possible interpretation, relying on the 
concept of dressed radiation associated to the electron, which may be termed 
as a sort of "escort field" or "massive photons" [3]. In the case of 
electrons the general formula [3] yields the invariant mass 9.2632 keV/c^2 
for this field, which is about 55 times smaller than that of the electron. 
According to our earlier work [4], the intensity parameter of the electron 
embedded in such a massive photon field should be increased by this same 
factor, in comparison with the vacuum value. Thus, a contribution to the 
red-shift in X-ray Compton scattering would appear, which may explain the 
measured anomaly [1-2].
[1] Fuchs M et al, Anomalous nonlinear X-ray Compton scattering. 2015 Nat. 
Phys. 11, 964-70.
[2] Kettle B et al, Anomalous two-photon Compton scattering. 2021 New J. 
Phys. 23 115008.
[3] Varró S, Proposal for an electromagnetic mass formula for the X17 
particle. Universe 2024, 10, 86. [https://doi.org/10.3390/universe10020086].
[4] Varró S, New exact solutions of the Dirac equation of a charged particle 
interacting with an electromagnetic plane wave in a medium. Laser Phys. 
Letters 10 (2013) 095301. E-print: arXiv:1305.4370 [quant-ph].

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Üdvözlettel:
Horváth Vera


ZIMÁNYINÉ HORVÁTH Vera
Látogatóközpont-vezető
Tel: +36 70 491 14 12
Email: vera.horvath AT eli-alps.hu<mailto:vera.horvath AT eli-alps.hu>

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