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The η -baryon interactions at low energies are studied using a model based on effective chiral Lagrangians, which consider baryons with spin 1/2 and spin 3/2 in the intermediate states. The interacting baryons considered in this work are B = N , Λ , Σ , Ξ. We calculate the expected total and differential cross sections, phase shifts, and polarizations in the center-of-mass frame of reference for each reaction. [ABSTRACT FROM AUTHOR]

Systematic measurements of the annihilation cross sections of low energy antinucleons were performed at CERN in the 80's and 90's. However the antiproton data on medium-heavy and heavy nuclear targets are scarce. The ASACUSA Collaboration at CERN has measured the antiproton annihilation cross section on carbon at 5.3 MeV: the value is (1.73 ± 0.25) barn. The result is compared with the antineutron experimental data and with the theoretical previsions. [ABSTRACT FROM AUTHOR]

Annihilation cross sections of antiprotons and antineutrons on the proton between 50 and 400 MeV/c show Coulomb focusing below 200 MeV/c and almost no charge-dependence above 200 MeV/c. Similar comparisons for heavier targets are not possible for lack of overlap between nuclear targets studied with $\bar {p}$ and $\bar {n}$ beams. Interpolating between $\bar {p}$-nucleus annihilation cross sections with the help of an optical potential to compare with $\bar {n}$-nucleus annihilation cross sections reveal unexpected features of Coulomb interactions in the latter. Direct comparisons between $\bar {n}$-nucleus and $\bar {p}$-nucleus annihilations at very low energies could be possible if $\bar {p}$ cross sections are measured on the same targets and at the same energies as the available cross sections for $\bar {n}$. Such measurements may be feasible in the foreseeable future. [ABSTRACT FROM AUTHOR]

Abstract: Recent theoretical developments in the unitary convolution approximation (UCA) for electronic energy losses of bare and screened ions are presented. Examples are given for proton beams and rare-gas targets. For gas targets there exists a sufficient amount of experimental data on charge exchange, for pinpointing the largely unknown stopping-power contribution of electron-capture processes at low and intermediate energies. [Copyright &y& Elsevier]

Abstract: Antiproton annihilation cross sections on medium-heavy and heavy nuclear targets are measured for the first time at 5.3 MeV kinetic energy at the Antiprotons Decelerator facility of CERN. The results agree with the expected behavior from the black-disk model with the Coulomb corrections. [Copyright &y& Elsevier]

possibility of describing experimental data for the astrophysical S-factor of pLi capture at low energies is discussed within the potential cluster model with forbidden states. [ABSTRACT FROM AUTHOR]

Based on new experimental investigations of elastic pLi scattering at energies 500-1150 keV and angles 30-170°, a phase analysis is performed and interaction potentials for pLi-system in S- and P-states are constructed. [ABSTRACT FROM AUTHOR]

The low-energy elastic cross-section in collisions of a muonic atom with the hydrogen isotope is investigated, employing a new wave function (trial) and using the coordinate-space Faddeev-Hahn model. The wave function includes non-adiabatic terms. Our results of s-wave cross-sections are given, at the tμ(1s) + d scattering. Calculated cross-sections are in good accord with the results published by Chiccoli et al., while having no good agreement with other recent reports. [ABSTRACT FROM AUTHOR]

Based on experimental research of elastic р12С scattering for energies of 200–1110 keV (in the center-of-mass system) and angles of 10–170°, the phase analysis of the р12С system in the S-state is performed and the interaction potential is constructed. [ABSTRACT FROM AUTHOR]

Values of the electron-screening potential derived from previous fits to measurements of low-energy cross sections of nuclear reactions have generally been much larger than the values estimated from model calculations. Here we refit the data using somewhat different procedures and show that better agreement is possible in some cases. [Copyright &y& Elsevier]

Some experimental limits on the annihilation cross sections σ ann of antiprotons on carbon, palladium, and platinum targets were determined at the previously unexplored kinetic energy region E ≈ 125 keV. Information on σ ann at such low antiproton energies is important in understanding the dynamics of the annihilation process, and provides useful data for models that attempt to describe the matter-antimatter asymmetry in the universe by assuming the existence of islands of antimatter concentration. [ABSTRACT FROM AUTHOR]

n additional pole term and the contributions to it from intermediate states with the same mass but with different spins is calculated for the Compton scattering amplitude on a two-particle system with zero total angular momentum. It is shown that the decomposition of invariant amplitudes on the generalized polarizabilities of the system does not take place if this term is taken into account. [ABSTRACT FROM AUTHOR]

Since 2012, a compact 250 kV Single Stage accelerator (250 kV-SSAMS) has been installed at Instituto de Física, Universidade Federal Fluminense, for radiocarbon analysis of natural samples. The system presents two magnets, for mass selection prior and post the gas stripper, and an electrostatic spherical analyzer (ESA). The overall performance of the machine makes it suitable for experimental researches in atomic collisions, in particular for studies of the stopping power of atomic projectiles at energies below 25 keV/u. Here we report on the energy loss measurements of 12C + and 16O + ions in a thin carbon foil at energies in the range of 10 to 25 keV/u. Energies of the ions after the foil are determined from the high-voltage applied to the ESA in order to recover the maximum intensity reading in a Faraday Cup (FC) after the ESA. Energies of the ions after the foil are determined from the high-voltage applied to the ESA. With this technique, experimental data for the stopping power within a precision of about 0.5%. [ABSTRACT FROM AUTHOR]