Synopsis We present ultra-high-resolution COLTRIMS data on single ionization of helium induced by 1 MeV proton impact and compare it with theoretical calculations. Our analysis clearly shows the ...limitations of the first Born approximation.
The modified final-state interaction theory taking into consideration the Coulomb interaction between two-fragment nuclear resonance decay products and accompanying reaction products is developed ...including the case of near-threshold resonances. The branching ratio change is also studied for the near-threshold resonance 7Li*(Ex = 7.45 MeV), which is formed in the reaction 7Li(α, α)7Li* at Eα = 27.2 MeV.
Abstract
We present a new parametrization of the d +
3
He → p +
4
He fusion reaction astrophysical factor based on the effective range approximation, which is an effective theoretical method for ...describing near-threshold, including resonance, nuclear reactions. In the framework of this approximation we describe experimental data on the energy dependence of the cross section and the astrophysical factor within the experimental uncertainties in the energy range of 0-800 keV. On this basis we calculate the temperature dependence of the Maxwellian-averaged reaction rate in the range of 0-400 keV. In conclusion, we discuss the effect of the calculated reaction rates on the Lawson criterion for thermonuclear reactors based on d-
3
He fuel.
In this review, a generalization of few-body quantum scattering theory is given for the case of Coulomb interaction. Since in this specific case the scattering amplitude, which is a solution to a ...resolvent-type equation, possesses a singularity when the complex parameter
z
tends to the energy shell, a definition of the physical amplitude is provided. A recipe for regularizing integrals (eliminating divergences), which describe the terms of a perturbation theory series for different perturbing potentials, is formulated. As an example, the general theory is applied to the calculations of differential cross sections for a quasi-elastic electron impact ionization reaction on atomic hydrogen.
This contribution delivers a generalization of multichannel quantum scattering theory to (e, 2e) ionization of an atom. Since in this specific case the scattering amplitude given by a solution of the ...resolvent-like equation exhibits a Coulomb singularity on the energy shell, a rigorous definition of the physical amplitude is provided and a recipe for regularizing the divergent (e,2e) Born series is formulated.
We consider the interaction of atomic hydrogen, in its ground state, with an electromagnetic pulse whose duration is fixed in terms of the number of optical cycles. We study the probability of ...excitation of the atom in the static field limit i.e. for field frequencies going to zero. Despite the fact that the well known Born-Fock adiabatic theorem is valid only for a system whose energy spectrum is discrete, we show that it is still possible to use this theorem to derive, in the low frequency limit, an analytical formula which gives the probability of transition to any excited state of the atom as a function of the field intensity, the carrier envelope phase and the number of optical cycles within the pulse. The results for the probability of excitation to low-lying excited states, obtained with this formula, agree with those we get by solving the time-dependent Schroedinger equation. The domain of validity is discussed in detail.
The processes of excitation and decay of high excited 5He resonances into the d + t channel have been studied in the reaction 7Li(d, α)5He* at the energy of deuteron beam Ed = 37 MeV. In the ...inclusive spectra of α-particles in addition to the contributions of well known 5He resonances, the high excited states with excitation energies Ex ~ 19 and Ex > 20 MeV were observed. Cluster decay of these resonances was also identified in αd- and αt-coincidence spectra. For the first time, the decay into the d + t channel was observed for 5He resonances with Ex = 22 and 26 MeV. The determined resonance energy and width are partly agreed with the R-matrix analysis of data obtained at the study of d + 3H and n + 4He binary reactions. The possible Coulomb effects in three-particle channels of reaction 7Li(d, α)5He* are also analyzed for different conditions of observation of high excited 5He resonances.
PDF
