Heavy-ion inelastic scattering

The ²⁴Mg(¹⁶O, ¹⁶O'γ)²⁴Mg(2⁺) reaction has been investigated at 42 MeV incident energy. In-plane (¹⁶O, γ) angular correlations were measured for outgoing ¹⁶O ions between 6° and 40°. The results are compared with DWBA and coupled channels calculations.     

Forward pion-nucleus elastic scattering amplitudes

Values for the real part of the forward scattering amplitude have been obtained using dispersion relations from an analysis of pion-nucleus total cross sections for ⁴He, ⁶Li and ¹²C. The results are compared with measured values and those predicted by simple optical models. The dependence of the derived values for the forward scattering amplitudes on uncertainties in the measured cross sections is also discussed.     

Elastic scattering of 9Be on light target nuclei

The elastic scattering of ⁹Be on the target nuclei ⁹Be, ¹²C, ¹³C and ¹⁶O was measured at projectile energies of 14, 20 and 26 MeV. All angular distributions show a diffraction-like structure. In addition, excitation curves were measured for the scattering of ⁹Be on ⁹Be at three different angles in the energy range of 9–22 MeV. An optical potential having parameters independent of mass number and energy and reproducing all the measured angular distributions in the forward angular region was found and compared with that for the scattering of ⁹Be on medium and heavy nuclei.     

Optical-model analysis of Li elastic scattering

The elastic scattering cross sections of 28 MeV ⁶Li ions from the nuclei ¹¹B, ¹²C and ¹³C were analyzed using the optical model. The analysis has been extended to other ⁶Li elastic scattering data on ¹⁶O (29.8 MeV) and on ¹²C (24.5 and 30.6 MeV) previously measured elsewhere. The fits obtained with the usual six-parameter Woods-Saxon potential are good. Parameter ambiguities were studied and the results of the analysis were compared with the predictions of the folding model.     

Neutron scattering from 208Pb

Elastic scattering of 7, 9, 11, 20 and 26 MeV neutrons from ²⁰⁸Pb has been measured with the Ohio University Tandem Van de Graaff accelerator. Standard pulsed beam time-of-flight techniques were employed. Measurements of the incident flux at 0° were used to normalize the differential cross sections. The measured cross sections were corrected for dead time, detector efficiency, flux attenuation, multiple scattering, finite geometry, neutron source anisotropy and compound elastic contribution. Relative uncertainties are estimated to be between 5%–10% and the uncertainty in the normalization is estimated to be less than 5 %. The data were used to obtain neutron optical potential parameters. A comparison with proton optical parameters is presented, and the (p, n) quasi-elastic cross section is calculated and compared with available data. Deformation parameters for the 3^? state (Q = ?2.615 MeV) and 5ā (Q = ?3.198 MeV) in ²⁰⁸Pb were obtained at incident energies of 11 and 26 MeV.     

Quadrupole spin-flip in elastic scattering of nucleons

We consider the contribution to the depolarization of elastically scattered nucleons which involves transfer of two units of angular momentum to the target nucleus. Our estimates for the depolarization approximate measured values for ⁹Be, ¹⁰B, and ²⁷Al.     

Two-photon exchange in deep inelastic scattering

We have measured the contribution of the two-photon exchange amplitude in deep inelastic muon-nucleon scattering. We find, with 95% confidence, that the real part of this amplitude is less than 0.017 of the one photon-exchange amplitude. The range of the 4-momentum transfer covered is 0.5 < Q² < 2.1 (GeV/c)².     

Proton-nucleus elastic scattering at 156 MeV

Cross sections for the elastic scattering of 156 MeV protons on eleven targets ranging from ¹²C to ²⁰⁹Bi were measured and an optical model analysis has been performed. The effect of different optical potentials in DWIA inelastic scattering calculations is shown by some examples.     

Alpha-nucleus elastic scattering at intermediate energies

Elastic scattering of 288,340,480 and 699 MeV Alpha-particles was measured on ²⁰⁸Pb, ¹¹⁶Sn and ⁵⁸Ni. The data were analysed in terms of a phenomenological optical model. The optical potentials obtained were found to vary consistently with the target nucleus and the incident energy. The radial zone where the potentials are well determined was studied in detail. The data for ²⁰⁸Pb were also analysed with a folding model. The energy dependence of the strong-absorption radius and of the reaction cross section shows that the nuclear surface becomes slightly transparent for incident energies above 150 MeV per nucleon.     

Measurement of isolated photon production in deep-inelastic scattering at HERA

The production of isolated photons in deep-inelastic scattering ep→eγX is measured with the H1 detector at HERA. The measurement is performed in the kinematic range of negative four-momentum transfer squared 4<Q²<150 GeV² and a mass of the hadronic system W_X>50 GeV. The analysis is based on a total integrated luminosity of 227 pb^-1. The production cross section of isolated photons with a transverse energy in the range 3<E_T ^γ<10 GeV and pseudorapidity range -1.2<η^γ<1.8 is measured as a function of E_T ^γ, η^γ and Q². Isolated photon cross sections are also measured for events with no jets or at least one hadronic jet. The measurements are compared with predictions from Monte Carlo generators modelling the photon radiation from the quark and the electron lines, as well as with calculations at leading and next to leading order in the strong coupling. The predictions significantly underestimate the measured cross sections.     

Elastic electron scattering on Zr and Mo

Elastic electron scattering on ⁹⁰Zr and ⁹²Mo has been measured at 200 and 300 MeV up to 2 fm⁻¹ momentum transfer. Data analysis led us to adopt the parabolic Gaussian shape as a valuable charge distribution for these nuclei. For ⁹⁰Zr, we have compared this model with charge distributions given by recent Hartree-Fock calculations.     

Spontaneous Raman scattering in atomic thallium vapor

Using a cw argon-ion laser, we have measured the spontaneous Raman scattering cross section, σ_R, and linewidth in atomic thallium vapor. For 4880-Å excitation, σ_R = 1.6 × 10^?27 cm². We observe no pressure broadening of the Raman line at vapor pressures to 100 torr.     

Neutron-helium scattering

Relative differential cross sections of neutrons elastically scattered from ⁴He were measured at neutron energies of 0.55, 0.84, 1.16 and 1.33 MeV. The scattered neutrons were detected in a time-of-flight spectrometer for c.m. angles ranging from 25° to 161°. The relative differential cross sections are compared to curves generated from phase shifts published elsewhere.     

Double folding model analysis of 7Li scattering

Elastic scattering angular distributions have been measured for the scattering of ⁷Li by ⁴⁴Ca, ⁵⁶Fe and ^{58, 60}Ni at $\text{E(}{}^7\text{Li}\text{) = 34}\text{MeV}$. These data are well described by the optical model using volume Woods-Saxon potentials. These and previously measured ⁷Li scattering data also have been analyzed with a double-folding real potential which employs the nucleon-nucleon potential of Bertsch et al. The overall best fit to the experimental data down to σ/σ_R ~ 10^?3 is obtained when the DF potential is multiplied by approximately 0.6. However, the best fit for the peripheral data alone (σ/σ_R ～ 10^?1 is obtained without any renonnalization.     

Polarized electron-proton scattering at highQ 2

We show that polarized electron-proton scattering is an excellent tool to measure helicity changing amplitudes. The asymmetry of polarized protons measured with longitudinally polarized electrons determines the ratio of Pauli (F ²) to Dirac (F ¹) form factors. For the leading Fock state the Pauli form factor originates only from helicity changing quarkgluon interactions which are zero for zero quark masses. Therefore at high momentum transfer the ratioF ²/F ¹ depends essentially on the up and down quark masses.     

Elastic scattering of20Ne on24Mg

High spin states in⁸⁵Rb and⁸⁵Sr were populated in the reactions⁷⁶Ge(¹²C,p2n) and⁷⁶Ge(¹²C,3n), respectively. The lifetimes of twelve states were measured via the recoil distance Doppler shift technique. The positive parity bands in both nuclei associated with theg _9/2 orbit exhibit decrasingE2 strengths for increasing spin value marking the onset of multiparticle excitation.     

Charge-symmetry breaking and n-n scattering lengths

Recent experimental and theoretical investigations of ρ-ω and η-π mixing have caused us to re-examine the effects of these mixings on the charge-symmetry breaking of nuclear forces. The charge asymmetry of the nucleon-nucleon force in the singlet S-state is used to predict the n-n scattering length in terms of the measured p-p one. The extra attraction of the n-n potential in the ¹S₀ state gives rise to a change of roughly −0.8 fm in the corresponding scattering length. The magnitude (and sign) of the charge asymmetry is approximately that required to understand the binding-energy differences of the mirror nuclei ³He-³H and ⁴¹Sc-⁴¹Ca.     

Neutron elastic scattering on T = 0 nuclei

Neutron elastic scattering on Si, S and Ca has been measured at 11, 20 and 26 MeV using the Ohio University 11 MeV Tandem Van de Graaff. A time-of-flight technique was used and the angular distributions covered an angular range from 15° through 155°. The measured cross sections were corrected for dead time, source anisotropy, detector efficiency, finite geometry, neutron flux attenuation and multiple scattering. Individual as well as global fits to the data using an optical-model search code are presented. The comparison of the optical-model analysis to the neutron and proton elastic scattering data in the case of ⁴⁰Ca, allows an empirical determination of the Coulomb correction term which may be parametrized as $\text{0.46 Z/A}\text{1}\text{3}$. It is also shown that the elastic scattering and inelastic scattering to the first 2⁺ states in ²⁸Si and ³²S may be fitted using the same optical-model parameters obtained for ⁴⁰Ca using the coupled-channel formalism.     

Alpha-particle inelastic scattering form factors in the Coulomb-nuclear interference region

Alpha-particle scattering cross sections have been measured at 15, 18 and 19 MeV from the ground state and first excited state of ⁵²Cr, ⁵⁶Fe, ⁶⁰Ni and ⁶⁴Zn. Excitation functions have also been measured for inelastic α-scattering from ⁵²Cr and ⁶⁰Ni. The data extends into the forwardangle Coulomb-nuclear interference region. The results are analysed with the optical model and DWBA, using the deformed potential model. The relative and absolute magnitudes of the nuclear and Coulomb deformation parameters and the shapes of the form factors have been deduced from the data. The importance of data in the Coulomb-nuclear interference region in determining these quantities is demonstrated.     

Study of depolarized Rayleigh scattering in liquid benzene derivatives

The spectrum of the depolarized Rayleigh line has been measured for benzene, toluene, fluorobenzene and bromobenzene (at 22°c). The central part of the spectrum was measured at high resolution using a piezoelectric scanned Fabry-Pérot with a maximum free-spectral range of about 20 cm^-1. The entire spectrum was also measured with a monochromator extending the region to 100 cm^-1. The results from the two techniques were combined in order to deduce the correct line shape from which we were able to determine two relaxation times τ1 and τ2.