Experimental Differential Cross Section Data Research Articles

Reaction 14C(11B, 12C)13B at Elab(11B) = 45 MeV, interaction of 13B + 12C versus that of 10,11,12B + 12C

New experimental data for differential cross-sections of the 14C(11B, 12C)13B reaction obtained recently at the energy Еlab(11B) = 45 MeV for the ground states of 13B and 12C were analyzed within the coupled reaction channels (CRC) method that included the 11B + 14C elastic scattering channel as well as channels for one- and two-step transfers of nucleons in the coupling scheme. The necessary 11B + 14C Woods - Saxon (WS) optical potential parameters for the entrance reaction channel were obtained from 11B elastic scattering in the previous work, while those for 12C + 13B interaction were deduced from fitting the CRC calculations to the 14C(11B, 12C)13B reaction data. Needed spectroscopic amplitudes of transferred nucleons and clusters were calculated within the translational-invariant shell model. The data are well described by the direct transfer of a proton while contributions from two-step transfers were found to be negligible. The deduced 13B + 12C WS optical potential parameters are compared with those of the 10,11,12B + 12C nuclei interactions. The effect of isotopic differences in these interactions was observed.

Production of light-flavor and single-charmed hadrons in pp collisions at TeV in an equal-velocity quark combination model * *Supported by Shandong Province Natural Science Foundation (ZR2019YQ06,ZR2019MA053), and National Natural Science Foundation of China (11975011) and Higher Educational Youth Innovation Science and Technology Program of Shandong Province (2019KJJ010)

We apply an equal-velocity quark combination model to study the production of light-flavor hadrons and single-charmed hadrons at midrapidity in the collisions at TeV. We find that the experimental data for the spectra of and exhibit the quark number scaling property, which clearly indicates the quark combination mechanism at hadronization. Experimental data for the spectra of , , , , , and are systematically described by the model. The non-monotonic dependence of the ratio is naturally explained, and we find that it is closely related to the shape of the logarithm of the strange quark distribution. Using the spectra of light-flavor quarks obtained from light-flavor hadrons and the spectrum of charm quarks, which is consistent with perturbative QCD calculations, the experimental data for differential cross-sections of , , and as functions of are systematically described. We predict the differential cross-sections of and . The ratio in our model is approximately 0.16, and is approximately 0.012, owing to the cascade suppression of strangeness. In addition, the predicted and ratios exhibit the non-monotonic dependence on in the low range.

Detailed analysis for 6Li+40Ca elastic scattering using different potentials

The available experimental differential cross-section data for the 6Li+40C nuclear system in the energy range of 20–240 MeV have been reanalyzed using the framework of the phenomenological optical model (OM), the semi-microscopic cluster folding optical model (CFOM), and the microscopic cluster folding model (CFM) motivated by the well-known cluster structure of 6Li. Reasonable fits to the experimental data have been obtained using OM, CFOM, and CFM over the entire energy range considered in this study. For the real cluster folding potential, the extracted average renormalization factors from CFM and CFOM calculations are 0.46 ± 0.14 and 0.56 ± 0.05, respectively. Due to the well-developed cluster structure of 6Li and the effect of its breakup on other reaction channels, the strength of the real cluster folding potentials was required to be reduced by ∼44%–54% in order to describe the experimental data.

Estimation of optical model parameters and their correlation matrix using Unscented Transform Kalman Filter technique

In the present study, we have optimized the optical model parameters and also calculated their correlation matrix using the Unscented Transform Kalman Filter technique for the first time. We have used n+56Fe, n+45Sc and n+59Co reactions for this study in order to verify the application of this method. We have used the experimental differential cross section data for the elastically scattered neutrons from the EXFOR data library and DWBA calculations to determine the parameters. In this study we have assumed that the optical model provides correct results and the uncertainties come from the variation of fitting parameters only. We have used the TALYS nuclear reaction code for the DWBA calculations. The optical model parameters determined through this study, reproduce the calculations which are consistent with the experimental trends for the elastically scattered neutrons and total reaction cross sections. Also the correlations calculated in this work are consistent with the earlier study of n+56Fe reaction.

МЕХАНІЗМИ РЕАКЦІЇ 14C(11B,10В)15С ЗА ЕНЕРГІЇ 45 МеВ ДЛЯ ОСНОВНИХ І ЗБУДЖЕНИХ СТАНІВ ЯДЕР 10В І 15С

New experimental data for differential cross-sections of the reaction 14C(11B,10B)15C at Еlab(11B) = 45 MeV were obtained for transitions to the ground and excited states of the exit reaction channel nuclei. The experimental data were analyzed within the coupled-reaction-channels method (CRC). The 14C + 11B elastic scattering channel as well as channels for one- and two-step transfers of nucleons and clusters were included in the coupling scheme. The Woods - Saxon (WS) potential was used in the CRC-calculations for the entrance reaction channel with the parameters deduced previously from the analysis of the experimental data of 11B + 14C elastic and inelastic scattering, whereas the WS potential for the exit 15C + 10B reaction channel was deduced from the fit of CRC cross-sections to the 14C(11B,10B)15C reaction experimental data. Needed for CRC-calculations spectroscopic amplitudes (factors) of the nucleons and clusters transferred in the reaction were calculated within the translational-invariant shell model. The mechanisms for one- and two-step transfers of nucleons and clusters were investigated in this reaction. The 15C + 10B potential parameters were deduced, and comparisons of the CRC reaction cross-sections calculated with the 15C + 10B and 12,13C + 10B potential parameters were performed. The differences between these CRC calculations were observed, e.g. "isotopic effects" were observed for the potentials of 10B interaction with 12,13,15C carbon isotopes.

A Review on Recent Developments in Deuteron Induced Reactions Enhancing NRA Capabilities

Nuclear Reaction Analysis (NRA) is well established as one of the principal IBA methods nowadays. Among the most important NRA characteristics are its high iso- topic selectivity, its enhanced sensitivity for many nuclides, the capability of least destructive depth profiling and the possibility of simultaneous analysis of more than one light element in near–surface layers of materials. Moreover, in the particular case when deuterium is used as probing beam, critical advantages for NRA studies emerge. As NRA quantifies individual light isotopes absolutely, and can depth pro- file with nanometer resolution, it is the most suitable ion beam technique for the determination of the concentration and depth profiling of light elements in complex matrices. However, as already pointed out in the recent literature, the application of NRA to the determination of the concentration and the depth profiling of light elements is frequently impeded by the lack of adequate and/or reliable experimental differential cross section data. It is the ambition of the present work to contribute in the fields of differential cross section measurements, as well as of data evaluation and general theoretical analysis.

Dirac coupled channel analyses of proton inelastic scattering from the 40Ar nucleus

0.8 GeV proton inelastic scatterings from $^{40}$Ar nucleus are analyzed using an optical potential model in the Dirac coupled channel formalism. A rotational collective model is used to obtain the transition optical potentials for the low lying excited states of the rotational band. The optical potential parameters of a Woods-Saxon shape and the deformation parameters of the excited states are searched phenomenologically to reproduce the experimental differential cross-section data by using the sequential iteration method. The effect of a multistep process is investigated by including the channel coupling between two excited states in addition to the couplings between the ground state and the excited states. The calculated deformation parameters of the excited states are compared with those obtained by using the nonrelativistic calculations. The results of the Dirac coupled channel calculations are found to show pretty good agreements with the experimental data of the ground state and the low-lying excited states. The multistep excitation process via the channel coupling with the second $2^+$ state is found to be important for the excitation of the $4^+$ state at the inelastic scatterings from the deformed nucleus, $^{40}$Ar.

Dirac phenomenological analyses of unpolarized proton inelastic scattering from 22Ne

Unpolarized 800 MeV proton inelastic scatterings from an s-d shell nucleus $^{22}$Ne are analyzed using phenomenological optical potentials in the Dirac coupled channel formalism. The first-order rotational collective model is used to obtain the transition optical potentials for the low lying excited collective states that belong to the ground state rotational band of the nucleus. The optical potential parameters of Woods-Saxon shape and the deformation parameters of the excited states are varied phenomenologically using the sequential iteration method to reproduce the experimental differential cross section data. The effective central and spin-orbit optical potentials are obtained by reducing the Dirac equations to the Schr\"odinger-like second-order differential equations and the surface-peaked phenomena are observed at the real effective central potentials when the scattering from $^{22}$Ne is considered. The obtained deformation parameters of the excited states are compared with those of the nonrelativistic calculations and another s-d shell nucleus $^{20}$Ne. The deformation parameters for the $2^+$ and the $4^+$ states of the ground state rotational band at the nucleus $^{22}$Ne are found to be smaller than those of $^{20}$Ne, indicating that the couplings of those states to the ground state are weaker at the nucleus $^{22}$Ne compared to those at the nucleus $^{20}$Ne. The multistep channel coupling effect is confirmed to be important for the $4^+$ state excitation of the ground state rotational band at the proton inelastic scattering from the s-d shell nucleus $^{22}$Ne.

Measurements and assessment of 12C(d,pγ)13C reaction cross sections in the deuteron energy range 740–2000 keV for analytical applications

The total cross sections of the 12C(d,pγ1)13C (Eγ=3089keV), 12C(d,pγ2)13C (Eγ=3684keV) and 12C(d,pγ3)13C (Eγ=3854keV) reactions, as well as differential cross sections for (d,po), (d,p1) reactions and (d,d0) elastic scattering were determined in the 740–2000keV deuteron energy range using a self-supporting natural carbon foil and detecting the gamma-rays and particles simultaneously. In order to test the validity of the measured gamma-ray producing cross sections, benchmark experiments were performed using kapton foils with two different thicknesses. Both the obtained gamma- and particle production cross section results were compared with data existing in literature, and in the case of (d,po) the experimental differential cross section data were compared also with the theoretical evaluated values.

Approximate Lane consistency of the dispersive coupled-channels potential for actinides

A previously derived dispersive coupled-channels optical model potential for nucleon scattering on $^{232}\mathrm{Th}$ and $^{238}\mathrm{U}$ nuclei [Capote, Soukhovitskii, Quesade, and Chiba, Phys. Rev. C 72, 064610 (2005)] has been tested against experimental data on quasielastic ($p,n$) scattering to the isobaric analog states of corresponding target nuclei. The Lane potential derived from the isovector term of the dispersive coupled-channels optical model potential has been shown to approximately reproduce available experimental differential cross-section data for the quasielastic ($p,n$) reaction; therefore the approximate Lane consistency of that potential has been established.

Fission neutron spectrum averaged cross sections for threshold reactions on arsenic

We have measured the cross sections, averaged over a 235U fission neutron spectrum, for the two high threshold reactions: 75As(n,p)75mGe and 75As(n,2n)74As. The measured averaged cross sections are 0.292±0.022 mb, referred to the 3.95±0.20 mb standard for the 27Al(n,p)27Mg averaged cross section, and 0.371±0.032 mb referred to the 111±3 mb standard for the 58Ni(n,p)58m+gCo averaged cross section, respectively. The measured averaged cross sections were also evaluated semi-empirically by numerically integrating experimental differential cross section data extracted for both reactions from the current literature. The calculations were performed for four different representations of the thermal-neutron-induced 235U fission neutron spectrum. The calculated cross sections, though depending on analytical representation of the flux, agree with the measured values within the estimated uncertainties.

Measurement of the50Ti(n,α)47Ca reaction cross section averaged over a235U fission neutron spectrum

The235U fission neutron spectrum averaged cross section for the50Ti(n,α)47Ca reaction was experimentally determined by irradiation of titanium with reactor neutrons. A value of (9.7±1.1) μb was found for this cross section, using (307±11) μb for the48Ti(n,p)48Sc spectrum-averaged cross section that was used as a standard. The50Ti(n,α)47Ca spectrum-averaged cross section was also semiempirically evaluated by numerically integrating, through the ENDF/B-V representation of the235U fission neutron spectrum, the available experimental differential cross section data.

Dirac equation analysis of intermediate-energy 3He-nucleus scattering.

A one-body Dirac equation is used to model $^{3}$He${+}^{40}$Ca elastic scattering at 197 and 217 MeV. A relativistic analogue of the Watanabe model is employed to constrain the real parts of the $^{3}\mathrm{nucleus}$ potentials. This procedure results in an accurate description of the experimental differential cross-section data, as well as a prediction of the elastic spin observables. Calculations for triton-nucleus scattering are also performed. Implications for relativistic models of nuclear scattering are discussed.

Some elementary viewpoints on the recording and analysis of angular distributions in experimental fast neutron elastic scattering

Total neutron elastic scattering cross-sections are usually estimated from the angular distributions of the differential cross sections. This circumstance makes some demands on the quality of the collection and evaluation of experimental differential cross-section data. In the present paper some problems associated with such measurements and effects which influence the analytical descriptions of the observations are discussed. Part of the paper is concerned with the problem of the proper fitting of a Legendre polynomial expansion to an experimental distribution which can only be recorded in a limited angular interval because of the geometrical dimensions of the shielding of a huge neutron detector. The effects of small angular shifts of some data points in the forward direction of angular distributions are discussed in some specific cases, namely for 209Bi and 208Pb at 8.05 and 25.7 MeV, respectively. Such shifts may be associated with a false position of the zero angle of the detector. A method is proposed for calibrating the zero-angle direction of the detector and some experimental results are reported.

Interaction potential for the X 1Σ state of Li + + Ar

The ground state potential curve of LiAr + was calculated using the configuration interaction (CI) method. Analysis of computational errors and comparison with experimental differential cross section data yields σ = 3.66 ± 0.05 α o, R e = 4.44 ± 0.05 α o, and D e = 0.30 ± 0.01 eV for the potential well parameters.

Scattering of thermal He beams by crossed atomic and molecular beams. II. The He–Ar van der Waals potential

Differential cross sections for He–Ar scattering at room temperature have been measured. The experimental consistency of these measurements with others performed in different laboratories is demonstrated. Despite this consistency, the present van der Waals well depth of 1.78 meV, accurate to 10%, is smaller by 20% to 50% than the experimental values obtained previously. These discrepancies are caused by differences between the assumed mathematical forms or between the assumed dispersion coefficients of the potentials used in the present paper and those of previous studies. Independent investigations have shown that the previous assumptions are inappropriate for providing accurate potentials from fits to experimental differential cross section data for He–Ar. We use two forms free of this inadequacy in the present analysis: a modified version of the Simons–Parr–Finlan–Dunham (SPFD) potential, and a double Morse–van der Waals (M2SV) type of parameterization. The resulting He–Ar potentials are shown to be equal to with experimental error, throughout the range of interatomic distances to which the scattering data are sensitive. The SPFD or M2SV potentials are combined with a repulsive potential previously determined exclusively from fits to gas phase bulk properties. The resulting potentials, valid over the extended range of interatomic distances r≳2.4 Å, are able to reproduce all these bulk properties quite well, without adversely affecting the quality of the fits to the DCS.

Energy spreading and angular distribution of a beam of electrons in molecular hydrogen

A Monte Carlo approach is used to obtain the energy spreading and angular distribution of initially monoenergetic and monodirectional beams of electron incident on a gas of molecular hydrogen. Several beams of primary electrons and the resultant secondaries are degraded in a step-by-step procedure which utilizes a detailed set of cross sections, together with reasonable approximations for the creation of secondary electrons. Particular attention is paid to the initial angular distribution of secondary electrons. An analytic function which characterizes current experimental differential cross-section data is used to provide realistic inputs into our calculations. The results for energy distribution as a function of distance and angular distribution at selected energies and distances are illustrated.

Total Cross Sections for the Excitation of the Triplet States in Molecular Nitrogen

A consistent set of total cross sections for electron impact excitation of the $A^{3}\ensuremath{\Sigma}_{u}^{+}$, $B^{3}\ensuremath{\Pi}_{g}$, $W^{3}\ensuremath{\Delta}_{u}$, ${B}^{\ensuremath{'}}^{3}\ensuremath{\Sigma}_{u}^{\ensuremath{-}}$, $C^{3}\ensuremath{\Pi}_{u}$, $E^{3}\ensuremath{\Sigma}_{g}^{+}$, and $D^{3}\ensuremath{\Sigma}_{u}^{+}$ triplet states of molecular nitrogen from the $X^{1}\ensuremath{\Sigma}_{g}^{+}$ state has been calculated quantum mechanically for incident electron energies from threshold to 80 eV. The Ochkur-Rudge exchange scattering and Franck-Condon approximations were employed to obtain these cross sections. Minimum and double-minimum basis-set LCAO-MO wave functions centered on the nuclei were used, and the multicenter terms in the scattering amplitude were evaluated using a $\ensuremath{\zeta}$-function expansion. Rotationally averaged cross sections were calculated for excitation from ${v}^{\ensuremath{'}\ensuremath{'}}=0$ to individual ${v}^{\ensuremath{'}}$ levels of the excited electronic states. The calculated total cross section for excitation of the $B^{3}\ensuremath{\Pi}_{g}$ state is in good agreement with that deduced from recent experimental data for the process. The cross section for excitation of the $C^{3}\ensuremath{\Pi}_{u}$ state agrees well with one pair of experimental measurements and is a factor of 2 larger than another pair of measurements and about a factor of 4 larger than a fifth experimental determination and the previous calculations. The calculated cross section for excitation of the $A^{3}\ensuremath{\Sigma}_{u}^{+}$ state is a good deal larger than previous theoretical and experimental estimates. However, a comparison with recent experimental differential cross-section data indicates that the theoretical $A^{3}\ensuremath{\Sigma}_{u}^{+}$ total cross section is correct for incident energies greater than about 35 eV. The relative magnitude of these excitation cross sections leads to interesting predictions concerning ${\mathrm{N}}_{2}$ processes in the upper atmosphere.

Multipole analysis of pion photoproduction below the first resonance

Different sets of multipoles are derived phenomenologically from the experimental differential cross section data of both π + and π o production. This is done by an iterative method using the multipoles of Berends, Donnachie and Weaver as a zeroth-order approximation. Predictions of experimental values of asymmetry ratios and recoil proton polarization are given. The energy region below the first resonance is examined.