Differential Cross Section Data Research Articles

Low energy elastic and inelastic scattering of positrons from formic acid

Abstract This paper presents a detailed study of low energy positron scattering from formic acid, examining elastic scattering, electronic excitation and ionisation processes. Through detailed comparisons with previous experimental and theoretical data, it is clear that the picture for positron scattering from this target remains incomplete, with significant disagreement between experiment and theory in the comparisons of differential cross section data. Calculations of elastic electron scattering are unexpectedly in better agreement with the positron scattering experiments, and give some hints as to potential areas for improvement in the modelling of scattering for targets which tend to be dominated by dipole interactions.

Elastic proton–neutron and antiproton–neutron scattering in holographic QCD

The total and differential cross sections of the elastic proton–neutron and antiproton–neutron scattering are studied in a holographic QCD model, focusing on the Regge regime. Taking into account the Pomeron and Reggeon exchange, which are described by the Reggeized spin-2 glueball and vector meson propagator respectively, those cross sections are obtained. It is presented that the currently available experimental data of the total cross sections can be well described within the model. Once a single adjustable parameter is determined with the total cross section data, the differential cross sections can be calculated without any additional parameters. Although the available differential cross section data are limited, it is found that our predictions are consistent with those.

New insights into the oscillations of the nucleon electromagnetic form factors

The electromagnetic form factors of the proton and the neutron in the timelike region are investigated. Electron–positron annihilation into antinucleon-nucleon (N¯N) pairs is treated in distorted wave Born approximation, including the final-state interaction in the N¯N system. The latter is obtained by a Lippmann–Schwinger equation for N¯N potentials derived within SU(3) chiral effective field theory. By fitting to the phase shifts and (differential) cross section data, a high quality description is achieved. With these amplitudes, the oscillations of the electromagnetic form factors of the proton and the neutron are studied. It is found that each of them can be described by two fractional oscillators. One is characterized as “overdamped” and dominates near the threshold, while the other is “underdamped” and plays an important role in the high-energy region. These two oscillators are essential to understand the distributions of polarized electric charges induced by hard photons for the nucleons.

Data driven isospin analysis of timelike octet baryons electromagnetic form factors and charmonium decay into baryon-anti-baryon

Inspired by the recent precise data, we perform model-independently an isospin decomposition of the timelike octet baryons electromagnetic form factors. As noted in our previous work, the relative magnitude of isoscalar and isovector component is determined with the input of data on various isospin channels. Herein we further assert that their relative phase can be constraint by the phase difference of oscillatory modulation of effective form factors between isospin channels. The framework is extended to analyze the data of differential cross sections and applied to the form factors of nucleon and hyperons with detail and isospin non-conservation of charmonium decay into baryon-anti-baryon as well. We address that isospin analysis is meaningful when the isospin broken scale is compared to or smaller than the uncertainties of data.

Lévy α-Stable Model for the Non-Exponential Low-|t| Proton–Proton Differential Cross-Section

It is known that the Real Extended Bialas–Bzdak (ReBB) model describes the proton–proton (pp) and proton–antiproton (pp¯) differential cross-section data in a statistically non-excludible way, i.e., with a confidence level greater than or equal to 0.1% in the center of mass energy range 546 GeV ≤s≤8 TeV and in the squared four-momentum transfer range 0.37 GeV2 ≤ −t ≤ 1.2 GeV2. Considering, instead of Gaussian, a more general Lévy α-stable shape for the parton distributions of the constituent quark and diquark inside the proton and for the relative separation between them, a generalized description of data is obtained, where the ReBB model corresponds to the α=2 special case. Extending the model to α<2, we conjecture that the validity of the model can be extended to a wider kinematic range, in particular, to lower values of the four-momentum transfer −t. We present the formal Lévy α-stable generalization of the Bialas–Bzdak model and show that a simplified version of this model can be successfully fitted, with α<2, to the non-exponential, low −t differential cross-section data of elastic proton–proton scattering at s=8 TeV.

Nonperturbative gluon exchange in pp elastic scattering at TeV energies

We investigate the two-gluon-exchange model of the Pomeron using nonperturbative gluon propagators characterized by a dynamical mass scale. We present the results for an analysis of the available $pp$ differential cross section data at TeV energies which accounts for dynamical gluon masses obtained from a non-linear version of the Schwinger-Dyson equations. We show that our two-gluon exchange model gives a very good description of the LHC data, provided we demand the Reggeization of the scattering amplitude and make a suitable choice for the convolution of proton wave functions.

Low-energy deuteron–alpha elastic scattering in cluster effective field theory

In this paper, we study the low-energy $$d{-}\alpha $$ elastic scattering within the two-body cluster effective field theory (EFT) framework. The importance of the $$d(\alpha ,\alpha ) d$$ scattering in the $$^6 \text {Li} $$ production reaction leads us to study this system in an effective way. In the beginning, the scattering amplitudes of each channel are written in a cluster EFT with two-body formalism. Using the effective range expansion analysis for the elastic scattering phase shift of S, P and D partial waves, the unknown EFT low-energy coupling constants are determined and the leading and next-to-leading orders EFT results for the phase shift in each channel are presented. To verify the accuracy of the results, we compare experimental phase shift and differential cross section data with obtained results. The accuracy of the EFT results and consistency with the experimental data indicate that the EFT is an effective approach for describing low-energy systems.

Extraction of ωn , ωp , and ϕN scattering lengths from ω and ϕ differential photoproduction cross sections on a deuterium target

In this study, we try to extract $\ensuremath{\omega}n$, $\ensuremath{\omega}p$, and $\ensuremath{\phi}N$ scattering lengths from the differential cross-section data of near-threshold $\ensuremath{\omega}$ and $\ensuremath{\phi}$ photoproductions at threshold ${t}_{\mathrm{thr}}$. The incoherent data of $\ensuremath{\omega}$ and $\ensuremath{\phi}$ photoproductions on deuterium target for scattering length extractions are provided by the CBELSA/TAPS Collaboration and LEPS Collaboration, respectively, where the deuteron is usually approximated as a weakly bound state of a quasifree neutron plus a quasifree proton. Under the vector meson dominance model and the assumption of energy independence of the differential cross section, we obtained the $|{\ensuremath{\alpha}}_{\ensuremath{\omega}{n}^{*}}|$ and $|{\ensuremath{\alpha}}_{\ensuremath{\omega}{p}^{*}}|$ of loosely bound neutron and proton in the deuteron to be 0.709 $\ifmmode\pm\else\textpm\fi{}$ 0.078 fm and 0.621 $\ifmmode\pm\else\textpm\fi{}$ 0.022 fm, respectively, at threshold ${t}_{\mathrm{thr}}$ for the first time by fitting the near-threshold data of $\ensuremath{\gamma}d$ $\ensuremath{\rightarrow}$ $\ensuremath{\omega}n(p)$ and $\ensuremath{\gamma}d$ $\ensuremath{\rightarrow}$ $\ensuremath{\omega}p(n)$. For a comparison study, we also extracted the scattering length $|{\ensuremath{\alpha}}_{\ensuremath{\omega}p}|$ of the free proton from the $\ensuremath{\omega}$ photoproduction on the hydrogen target by the CBELSA/TAPS Collaboration. With the near-threshold and incoherent $\ensuremath{\phi}$ photoproduction data of $\ensuremath{\gamma}d$ $\ensuremath{\rightarrow}$ $\ensuremath{\phi}pn$ by the LEPS Collaboration, we obtained scattering length $|{\ensuremath{\alpha}}_{\ensuremath{\phi}N}|$ of the bound nucleon inside the deuteron to be 0.109 $\ifmmode\pm\else\textpm\fi{}$ 0.008 fm at threshold ${t}_{\mathrm{thr}}$. The obtained $|{\ensuremath{\alpha}}_{\ensuremath{\omega}p}|$ and $|{\ensuremath{\alpha}}_{\ensuremath{\phi}N}|$ are basically in agreement with the experimental indications and the theoretical predictions within the current uncertainties.

Determination of Parton Distribution Functions with Jets at Forward Rapidity Region Using xFitter Analysis Framework

Parton distribution functions (PDF), which have to be determined from the measurements, are one of the main components to define the physics that occurs at the hadron colliders. In this study, a quantum chromodynamics (QCD) analysis was performed at the next-to-leading order (NLO) in the xFitter framework which is an open source QCD fit platform. Along with the HERA1+2 DIS and the jet differential cross-section data measured in the forward rapidity region (3.2 < |y| < 4.7) of the CMS detector in the LHC in proton-proton collisions at s = 8 TeV were used in xFitter analysis framework. Particularly gluon distribution functions were emphasized.

DIGE differential cross-section data for 6Li and 19F analysis

In this work we report the absolute differential cross-sections for the 429, 478 and 656 keV gamma-rays emission from the nuclear reactions 6Li(d, nγ)7Be, 6Li(d, pγ)7Li and 19F(d, pγ)20F, respectively. The energies of the incident deuterons were varied from 790 to 1995 keV in steps of 30 and 50 keV. The target was a thin natLiF layer evaporated onto a self-supporting Ag film. The gamma-rays were detected using an HPGe detector placed at an angle of 90° with respect to the beam direction. The obtained cross-sections were compared with the existing data in literature. The validity of measured cross-sections was checked through a thick target benchmarking procedure. All sources of the uncertainties in the measurements were deduced and reported.

Light baryon resonances from a coupled-channel study including mathbf {KSigma } photoproduction

The Jülich-Bonn dynamical coupled-channel approach is extended to include KSigma photoproduction off the proton. Differential cross section and (double) polarization data for K^+Sigma ^0 and K^0Sigma ^+ are analysed simultaneously with the pion- and photon-induced production of pi N, eta N, KLambda , and KSigma final states, totaling almost 72,000 data points for center-of-mass energies W<2.4 GeV. Based on the fit results the spectrum of N^* and Delta resonances is extracted in terms of pole positions and residues. We discuss the impact of the gamma prightarrow KSigma channels in detail and investigate the influence of recent polarization data for eta p photoproduction.

The ReBB model and its H(x) scaling version at 8 TeV: Odderon exchange is a certainty

The Real Extended Bialas-Bzdak (ReBB) model is shown here to describe, in the 0.37 le -t le 1.2 GeV^2 region, the proton-proton elastic differential cross section data published by the TOTEM Collaboration at LHC at sqrt{s} = 8 TeV center of mass energy. In this kinematic range, corresponding to the diffractive minimum-maximum region, a model-dependent Odderon signal higher than 18 sigma is obtained by comparing the ReBB model prediction for the p{bar{p}} elastic differential cross section to this TOTEM measured pp elastic differential cross section data at 8 TeV. However, when combining this signal with the Odderon signals from the ReBB model in the 0.37 le -t le 1.2 GeV^2 four-momentum-transfer range at sqrt{s} = 1.96, 2.76 and 7 TeV, it turns out that the combined significance is dominated not by the new 8 TeV but by that of earlier 7 TeV TOTEM data, that carry an even larger Odderon effect. Thus, in any practical terms, within the framework of the ReBB model, the Odderon signal in the limited 0.37 le -t le 1.2 GeV^2 and 1.96 le sqrt{s} le 8 TeV kinematic region is not a probability, but a certainty. We show also that the H(x) scaling version of the ReBB model works reasonably well at 8 TeV in the 0.37 le -t le 0.97 GeV^2 region.

A Simple Model for Describing the Minimum Differential Cross-Section of Elastic Proton Scattering on Protons at High Energies

Relevance. The most modern and widely applied phenomenological theory, which well describes an entire range of physical characteristics of such processes as elastic and inelastic proton-proton and antiproton-proton scattering at high energies, is the Regge poles method in relativistic theory. Based on a simple amplitude, such as the dipole pomeron, where the pomeron is the Regge pole, the researchers add different terms to it. Using such more complex amplitudes, it is possible to explain well or satisfactorily together not only the experimental data for these reactions obtained at the end of the last century, but also the latest ones obtained at the Large Hadron Collider. Purpose. The purpose of this study is to find numerical values of the amplitude parameters at which the circumferences of the differential cross-sections of elastic proton scattering on protons at high energies are satisfactorily described, and to answer whether the parameters satisfy the obtained constraints. Methods. To find the amplitude parameters, the least squares method is used and minima equations are obtained for the squares of differences between the experimental and theoretical values of these cross-sections. These equations are transcendental, and therefore, they are solved by approximation. Within the framework of successive approximations, a method is selected that ensures fast convergence of the process, namely: the faster descent method or the gradient method. Parameter errors are calculated using a covariance matrix. The statistical acceptability of the model is determined according to the Fischer criterion. Results. Numerical calculations from experimental data of differential cross-sections of elastic pp-scattering were used to find the values of the parameters and the scale multiplier of the amplitude. Differential cross-sections are calculated from the amplitude near the minima. The corresponding graphs of these cross-sections are presented. The coincidence with the experiment is satisfactory in most cases, and in some cases, it is of high quality. A covariance matrix is obtained, from which the errors of the model parameters are found. Under general conditions, restrictions on the found approximate values of parameters are derived. It is shown that they satisfy the constraint. According to the Fischer criterion, the statistical acceptability of the model was verified, which turned out to be positive. Conclusions. The proposed simple amplitude ensures that the Froissard constraint and unitarity are met. It will serve as a seed for constructing more complex amplitudes that will describe a wide range of experiments on proton-proton and antiproton-proton scattering at high energies.

The neutron and proton mass radii from the vector meson photoproduction data on the deuterium target

In this study, we try to extract the mass radii of the neutron and the proton from the differential cross section data of near-threshold $$\omega $$ and $$\phi $$ photoproductions on deuterium target, which is often approximated as a quasi-free neutron plus a quasi-free proton. The incoherent data of $$\omega $$ and $$\phi $$ photoproductions are provided by CBELSA/TAPS collaboration and LEPS collaboration respectively, where the deuteron is disintegrated in the experiments to measure the properties of individual nucleons. Under the VMD model and the assumption of dipole gravitational form factor, we determined the loosely bound neutron and proton mass radii to be $$0.795\pm 0.092\mathrm (stat.)\pm 0.073\mathrm (syst.)$$ fm and $$0.744\pm 0.029\mathrm (stat.)\pm 0.042\mathrm (syst.)$$ fm respectively from the near-threshold data of $$\gamma d \rightarrow \omega n (p)$$ and $$\gamma d \rightarrow \omega p (n)$$ , for the first time. With the near-threshold and incoherent $$\phi $$ photoproduction data of $$\gamma d \rightarrow \phi p n$$ , we determined the average mass radius of the bound nucleon (neutron or proton) inside the deuteron to be $$0.755\pm 0.039\mathrm (stat.)\pm 0.039\mathrm (syst.)$$ fm, for the first time. For a comparison study, we also extracted the mass radius of the free proton from the $$\omega $$ photoproduction on the hydrogen target by CBELSA/TAPS collaboration. Based on our analysis results under the assumptions of VMD model and a low energy QCD theorem, we find that the neutron mass radius is consistent with the proton mass radius within the current statistical uncertainties, and that the nuclear modification on the nucleon mass radius is small inside the deuteron.

Differential Ionization Cross Sections of HCl Molecule

In this article, the differential ionization cross-sections of the HCl molecule in the gas phase is investigated. The single differential ionization cross-section (SDCS) as a function of loss of incident electron energy and Double Differential Cross Section (DDCS) as a function of energy loss of incident electron and incident angle, is calculated. To reach exact values of differential ionization cross sections for HCl molecule, a modified semi-empirical approach of Jain and Khare is used. Partial and total absolute ionization cross-section of HCl is available but there is no data for differential ionization crosssections. So, first time, the results for single and double differential ionization cross-sections for HCl molecule is investigated.

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.

Form Factor and rms Radius of Proton Predicted Using Differential Cross-Section Data of $${p\bar{p}}$$ Elastic Scattering at $${\sqrt{s}=31}$$, 53, 62 and 1960 GeV

Form Factor and rms Radius of Proton Predicted Using Differential Cross-Section Data of $${p\bar{p}}$$ Elastic Scattering at $${\sqrt{s}=31}$$, 53, 62 and 1960 GeV

Results of analysis of Σ+p scattering events in J-PARC E40 experiment: differential cross sections and phase shifts of 3S1 and 1P1 states

We performed a novel Σ+p scattering experiment at the J-PARC Hadron Experimental Facility. Approximately 2400 Σ+p scattering events were identified by a kinematical consistency check for the recoil proton. The differential cross sections of the Σ+p elastic scattering were derived with better precision than in previous experiments. By exploiting high-quality differential cross section data and the simple representation of Σ+p interaction in the SU(3) flavor symmetry, we performed a phase-shift analysis on hyperon-nucleon scattering data for the first time. The absolute value of the phase shift of the 3S1 channel, where a large repulsive force was predicted due to the Pauli exclusive effect between quarks, was evaluated. These results indicate that the interaction of the 3S1 channel in the Σ+p channel is moderately repulsive, as the Nijmegen extended-soft-core models predicted.

Evaluation of electron ionization cross-sections of CFCl3 molecule by using a semi-empirical approach

In the present paper, we have investigated partial and total electron ionization cross-sections for CFCl3 molecule from ionization threshold to 5 keV incident electron energy using a modified Jain-Khare semi-empirical approach. The present results of ionization cross-sections show good agreement with available data sets. We also have investigated the ionization rate coefficients for its partial and total ionization cross-sections. The first time we have investigated single differential cross-sections at constant incident energies and double differential cross-sections at different incident energies and different incident angles. No other data of differential cross-sections are available to date for comparison to our results.

Photoproduction reaction γn → K *0Λ in an effective Lagrangian approach * *Supported by the National Natural Science Foundation of China (12175240, 11475181, 11635009), the Fundamental Research Funds for the Central Universities, the Key Research Program of Frontier Sciences of Chinese Academy of Sciences (Y7292610K1), and the China Postdoctoral Science Foundation (2021M693142)

In our previous work [Phys. Rev. C 101, 014003 (2020)], the photoproduction reaction was investigated within an effective Lagrangian approach. The reaction amplitudes were constructed by including the t-channel K, , and κ exchanges, u-channel Λ, Σ, and exchanges, s-channel N, , and exchanges, and interaction current. The data on the differential cross sections and spin density matrix elements were described simultaneously. In this study, we investigate the photoproduction reaction based on the same reaction mechanism as that of to obtain a unified description of the data for and within the same model. All hadronic coupling constants, form factor cutoffs, and the resonance masses and widths in the present calculations remain the same as in our previous work for . The available differential cross-section data for are well reproduced. Further analysis shows that the cross sections of are dominated by the contributions of the t-channel K exchange, while the s-channel and exchanges also provide considerable contributions.