Elastic differential cross sections of electron scattering by CF_4 at intermediate energies

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A measurement of the inclusive π0 and η production cross sections at high pT in p̄p and pp collisions at s = 24.3 GeV

Inclusive π⁰ and η production at large transverse momentum were studied in both p̄p and pp interactions at √s = 24.3 GeV. The experiment was performed using an internal molecular hydrogen gas jet target in the CERN SPS collider. No significant differences between production in p̄p and pp were observed in the transverse momentum range 2.5 < P_T < 5.1 GeV/c.     

The 7Li(p, α)4 He cross section at low energies

The reaction cross section for ⁷Li(p, α)⁴He was obtained from E_c.m. = 25 to 873 keV corresponding to the temperature range T = (0.033 to 6.8) × 10⁹ K. The data are in fair agreement with R-matrix calculations. Constraints drawn on the universal baryon density from the abundance of ⁷Li remain essentially unchanged by the present data.     

The π+ d → pp reaction at intermediate energies

Conclusion The joint efforts of the laboratories with intermediate energies accelerators at ANL, KEK, LANL, LNPI, Saclay, SIN and TRIUMF produced a rather definite picture of the ⁺pp reaction in the isobar region. However the problem of anomalies for the square-root branch point due to the production of isobar in the intermediate state have not been resolved so far. The poles obtained in different phenomenological analyses could be just the effective parametrization of these cuts (see e.g. [13]). Anyway, some singularities are definitely necessary to describe the data.The experimental data in regions s < 2·05 GeV and s < 2·25 GeV are clearly insufficient. Further accumulation of the data in these regions is necessary. Polarized deuteron data are badly needed in the whole kinematical range [13]. Besides as it was mentioned before it is necessary to measure accurately cross sections of other inelastic reactions which are important for the investigation (observation?) of dibaryonsNN N, NN andd N, NN [21]. It would be of interest also to measure cross sections of non quasi two-particle channels likeNN N, 2N andd N, 2N [22]. (In the case ofNN scattering quasi two-particle channels are known to dominate in a wide energy range.)Presented at the symposium Mesons and Light Nuclei, Bechyn, Czechoslovakia, May 27–June 1, 1985.I am grateful to L. A. Kondratyuk, M. G. Ryskin and M. I. Strikman for valuable discussions of the considered problems.     

A mean-field description of (γ, pi) cross sections at medium energies

Differential (γ, p_i) cross sections on ¹⁶O and ⁴⁰Ca have been calculated within a single-particle direct knock-out model, for photon energies between 40 and 400 MeV. It is shown that generating the bound and scattered states in a Skyrme Hartree-Fock (HF) mean-field, one can account for the global features of the data. Hereby, the role of the velocity-dependent part of the nucleon-nucleon interaction is emphasized.     

Microscopic description of the reactions d + d → p + 3H and d + d → n + 3He at low energies

A collective adiabatic approach is used to explore the total and differential cross sections for the reactions d + d → p + ³H and d + d → n + ³He at incident-deuteron energies of up to 6 MeV. All substantially contributing partial waves of order not higher than that of G waves are taken into account. The experimental value of the difference of the cross sections for the above mirror reactions is reproduced theoretically under the assumption that nuclear forces obey the condition of isotopic invariance. The positions and amplitudes of the maxima in the calculated total cross sections virtually coincide with those of the corresponding experimental values. It is shown that, around the maxima of the cross sections under study, dominant contributions to them come from the P wave. The sensitivity of observables to the parameters of nucleon-nucleon interaction is analyzed.     

Electron scattering by O_2 at intermediate and high energies

A complex optical model potential correlated by the concept of bonded atoms, which considers the overlapping effect of electron clouds between two atoms in a molecule, is firstly employed to calculate the absolute differential cross sections, the integrated and momentum transfer cross sections for electrons scattered by O2 at     

Measurement of the 6Li(e,e′p) reaction cross sections at low momentum transfer

The triple differential cross sections for the ⁶Li(e,e′p) reaction have been measured in the excitation energy range from 27 to 46 MeV in a search for evidence of the giant dipole resonance (GDR) in ⁶Li. The cross sections have no distinct structures in this energy region, and decrease smoothly with the energy transfer. Angular distributions are different from those expected with the GDR. Protons are emitted strongly in the momentum-transfer direction. The data are well reproduced by a DWIA calculation assuming a direct proton knockout process.     

D* meson production cross sections in e − p and e + p scattering processes at the HERA collider

The cause of the D* meson production cross sections in e ^? p and e ⁺ p deep inelastic scattering processes in the ZEUS experiment at the HERA collider that are anomalously different is determined.     

A search for narrow states in antineutron-proton total and annihilation cross sections near N̄N threshold

The n̄p total and annihilation cross section have been measured from near N̄N threshold (1880 MeV) to 1940 MeV with RMS resolution ranging from 0.08 MeV (1880 MeV) to 6.7 MeV (1940 MeV). No significant narrow meson structures were seen, with 90% CL upper limits of 40–180 mb-MeV on σΓ for states with width less than our resolution. Combined with increasing unitarity bounds on σ as one approaches threshold, these limits confine widths of possible predicted states below 1900 MeV to less than ∼ 1 MeV.     

Measurements of the total π-He and p-He cross sections and the slopes of the forward diffraction peak at energies from 50 to 300 GeV

Differential cross sections for elastic scattering of pions and protons on helium have been measured at incident momenta ranging from 50 to 300 GeV/c in the t-range 0.008 < | < | < 0.05 (GeV/c)². Both recoil α-particles and forward particles were detected in this experiment. The experimental method provided an absolute normalization of the cross sections with an estimated precision of 1%. From the analysis of the data, the diffraction slope parameters and total cross sections have been obtained. The results are compared with Glauber model calculations.     

Prospects for p̄p → ȲY studies at PANDA

Strangeness and charm production provide an excellent probe of QCD in the confinement domain. With the PANDA detector at FAIR, this can be studied in e.g., hyperon production in the p?p → ?Y reactions. In PANDA, all ground state strange hyperons and single charmed Λ’s will be accessible. Simulations show that the differential cross sections and spin observables can be well reconstructed for these reaction channels.     

Measurement of the2H(d, γ)4He reaction at intermediate excitation energies

The²H(d, )⁴He differential cross section was measured at deuteron laboratory energies of 20, 24, and 28 MeV between _cm=45° and _cm=135°. AtE _d =28 MeV a complete angular distribution was determined and fitted with Legendre polynomials. The ratioR=d/d (_cm=90°)/d/d (_cm=135°) was measured for each deuteron energy.