Related papers: Positronium-Atom Collisions
A theoretical study was conducted on the impact of electron and positron impact ionization of excited hydrogen atoms that were in the 3s state; this study was conducted within the First-Born Approximation (FBA), which provides an analytical…
The contribution of the low-lying nucleon resonances $P_{33}(1232)$, $P_{11}(1440)$ $D_{13}(1520)$ and $S_{11}(1535)$ to the invariant mass spectra of di-electrons stemming from the exclusive processes $pp\to pp e^+e^-$ and $pn\to pn…
High-$p_T$ particle spectra in $p+p$ ($\bar p + p$), $p+A$ and $A+B$ collisions are calculated within a QCD parton model in which intrinsic transverse momentum, its broadening due to initial multiple parton scattering, and jet quenching due…
A new method for calculations of electron-positron pair-creation probabilities in low-energy heavy-ion collisions is developed. The approach is based on the propagation of all one-electron states via the numerical solving of the…
We calculate the T-matrices of pseudoscalar meson octet-baryon scattering to one-loop order in SU(3) heavy baryon chiral perturbation theory. The pertinent combinations of low-energy constants are determined by fitting to phase shifts of…
The many-body-theory approach to positronium-atom interactions developed in [Phys. Rev. Lett. \textbf{120}, 183402 (2018)] is applied to the sequence of noble-gas atoms He-Xe. The Dyson equation is solved separately for an electron and…
Collisions of Bose-Einstein condensates can be used as a mean to generate correlated pairs of atoms. The scattered massive particles, in analogy to photon pairs in quantum optics, might be used in the violation of Bell's inequalities,…
Relativistic corrections to the hyperfine splitting are calculated for the triplet $2^3S_1$ state of the helium isotope He$^3$. High precision variational wave functions are employed, where the electron-electron correlations are well…
We calculate the hadron spectra in high-energy pp, pA and AA collisions within a pQCD parton model. Analyses of experimental data show that the modification of the spectra in pA and AA as compared to that in $pp$ collisions is consistent…
We focus on the problem of disentangling the single (SPS) and double (DPS) parton scattering modes in the production of \J pairs at the LHC conditions. Our analysis is based on comparing the shapes of the differential cross sections and on…
Electro-production of several pentaquark states is investigated in this paper. eSTARlight package is adapted to study the electro-production of $J/\psi$ and $\Upsilon (1S)$ via pentaquark $P_c$ and $P_b$ resonance channels in $e p \to e…
The elastic collision between two H-like atoms utilizing an ab-initio static-exchange model (SEM) in the center of mass (CM) frame considering the system as a four-body Coulomb problem where all the Coulomb interaction terms in the direct…
We present a theoretical and computational study of positron supercritical resonances in systems consisting of two highly-charged bare nuclei. The resonance positions and widths depending on the internuclear separation are calculated with…
Using the experimental data on total {\it S}=1 transition cross-sections \, for $^4$He$(\gamma,p)$$^3$H and $^4$He$(\gamma,n)$$^3$He reactions as the base, the paper describes the possibility of measuring the probability of {\it P}-states…
We present results on the scattering lengths of ^4He--^4He_2 and ^3He--^4He_2 collisions. We also study the consequence of varying the coupling constant of the atom-atom interaction.
We estimate differential rapidity cross sections for $\Psi$ and $\Upsilon$ production via p-Pb collisions at 8 TeV. We use the mixed heavy quark hybrid theory in which the $J/\Psi(1S),\Upsilon(1S),\Upsilon(2S)$ are standard mesons while the…
The scattering of $W$, $Z$ and Higgs bosons in the Standard Model is investigated in the region $s,m_H^2\gg m_W^2$ with no restrictions on relative sizes of $s$ and $m_H^2$, so that our results are applicable at energies below as well as…
We estimate the relative probabilities of $\Psi'(2S)$ to $J/\Psi$ production at BNL-RHIC and $\Upsilon(nS)$ production at the LHC and Fermilab in p-p collisions, using our recent theory of mixed heavy quark hybrids, in which the $\Psi'(2S)$…
High-order perturbative corrections to positronium decays and hyperfine splitting are briefly reviewed. Theoretical predictions are compared to the most recent experimental data. Perspectives of future calculations are discussed.
Hydrogen and helium emission lines in nebulae form by radiative recombination. This is a simple process which, in principle, can be described to very high precision. Ratios of He I and H I emission lines can be used to measure the…