Related papers: Annihilation explosions in macroscopic polyelectro…
Multi-body dark matter annihilation is commonly expected to be suppressed by higher-order couplings and phase-space factors, therefore being ignored thus far. We show that, however, this does not hold for a class of nonthermal dark matter…
The process of electron-positron pair creation by a high-energy electron in a medium is analyzed. The spectral distribution over energies of created particles is calculated for the direct and cascade mechanisms of the process. The Coulomb…
The absorption of a high-energy photon from the external cosmic gamma-ray background in the inner neutron star magnetosphere triggers the generation of a secondary electron-positron plasma and gives rise to a lightning - a lengthening and…
Spectra of unbound electron-positron pairs (dielectrons, in brief) and photons from decays of parapositronia produced in ultraperipheral collisions of electrically charged objects are calculated. Their shapes at energies of the NICA…
The two-photon positron annihilation density matrix is found to separate into a diagonal center of energy factor implying maximally entangled momenta, and a relative factor describing decay. For unknown positron injection time, the…
We present a detailed quantitative description of the recently proposed "slingshot effect" [Fiore, Fedele, De angelis 2014]. Namely, we determine a broad range of conditions under which the impact of a very short and intense laser pulse…
We present the results of a new experimental study of the quantum entanglement of photon pairs produced in positron-electron annihilation at rest. The experimental setup includes a system of Compton polarimeters to measure the Compton…
The positron-electron pair annihilation in two photons is known for its numerous applications using PET scanners. The decay of Positronium (Ps) from a standard sealed source in more than two photons is less likely but can be observed with a…
Calculations of gamma spectra for positron annihilation on a selection of molecules, including methane and its fluoro-substitutes, ethane, propane, butane and benzene are presented. The annihilation gamma spectra characterise the momentum…
The two-photon annihilation of a positron with an electron bound in the 1s state of a H-like ion is calculated within the fully relativistic QED framework. The interaction with the nucleus is treated nonperturbatively, thus allowing the…
The interaction of charged particles and photons with intense electromagnetic fields gives rise to multi-photon Compton and Breit-Wheeler processes. These are usually described in the framework of the external field approximation, where the…
We calculate the luminosity and energy spectrum of the neutrino emission from electron-positron pair annihilation during the collapse of a supermassive star (${M} \ga 5\times10^4 {M_\odot}$). We then estimate the cumulative flux and energy…
The process of the muon (pion) pair production with small invariant mass in the electron--positron high--energy annihilation, accompanied by emission of hard photon at large angles, is considered. We find that the Drell--Yan picture for…
The square of the four momentum of a photon in vacuum is zero. However, in an unmagnetized plasma it is equal to the square of the plasma frequency. Further, the electron-photon coupling vertex is modified in a plasma to include the effect…
The spectrum of electrons and positrons originating from vacuum decay occurring in the collision of two non-colinear laser pulses is obtained. It displays high energy, highly-collimated particle bunches traveling in a direction separate…
Microquasars are stellar-mass black holes accreting matter from a companion star and ejecting plasma jets at almost the speed of light. They are analogues of quasars that contain supermassive black holes of $10^6$ to $10^{10}$ solar masses.…
Annihilations of weakly interacting dark matter particles provide an important signature for the possibility of indirect detection of dark matter in galaxy halos. These self-annihilations can be greatly enhanced in the vicinity of a massive…
A simple analytical solution for the problem of multiphoton detachment from negative ions by a linearly polarized laser field is found. It is valid in the wide range of intensities and frequencies of the field, from the perturbation theory…
A free electron can temporarily gain a very significant amount of energy if it is overrun by an intense electromagnetic wave. In principle, this process would permit large enhancements in the center-of-mass energy of electron-electron,…
Studies based on imaging the annihilation of the electron (e$^{-}$) and its antiparticle positron (e$^{+}$) open up several interesting applications in nuclear medicine and fundamental research. The annihilation process involves both the…