Total Cross Sections Research Articles

Total cross section measurements of electron scattering from NH3 in the intermediate-energy region

Total cross section measurements of electron scattering from NH3 in the intermediate-energy region

Development of nanosized graphene material for neutron intensity enhancement below cold neutron energy

We have been developing nanosized graphene, called graphene flower, as a material that induces coherent scattering very cold neutrons. Previous experiments have found that the seed part of the graphene flower is more effective than the petal part in increasing the coherent scattering. Based on these results, we found that further modification of the graphene flower to increase the seed portion increased the total cross-section, although it did not reach the level of nanodiamonds.

Developed concrete reinforced by waste of lead fishing weights and steel nails as gamma rays and neutrons shields for nuclear power reactors

Wastes of steel nails WSN and wastes of lead fishing weights WLFW were successfully recycled in concrete to enhance its ability to attenuate neutrons and gamma rays. A series of studies on the effect of partially replacing coarse aggregates of concrete with different percentages (5, 10, and 20%) of WSN or WLFW on the density, slump, compressive strength, and attenuation of neutrons and gamma rays were implemented. The compressive strength of WSN-reinforced concrete ranged between 36.2 and 45.2 MPa, while that of WLFW-reinforced concrete ranged between 28.6 and 45.1 MPa. The ability of WSN- or WLFW-reinforced concrete to attenuate neutrons and gamma rays was tested by using two types of neutron energies; slow and total slow neutrons; and three gamma rays energies 661.64, 1173.23, and 1332.51 keV. Slow and total slow neutrons macroscopic cross-section, linear and mass attenuation coefficients of gamma rays, and half value layer for both types of nuclear radiation were obtained. The results showed that there is a significant improvement in the slow and total slow neutron attenuation efficiency of the considered concrete when reinforced by WSN or WLFW. On the other hand, due to the increase in the atomic number and density of both Fe present in WSN and Pb in WLFW, the attenuation ability of the studied gamma ray energies increased. The WLFW-reinforced concrete showed better value in the gamma rays and neutrons attenuation parameters compared to the WSN-reinforced concrete. Hence, the considered concretes reinforced by WSN or WLFW are a distinguished choice as radiation shields in nuclear power reactors, in addition to their adaptability to high concentrations of waste.

Theoretical Calculation of Gamma-Ray and Neutron Shielding Properties for CsPbBr3-Polypropylene Composite Material

The impact of CsPbBr3, known for its high atomic number and cross section with neutrons, on the gamma-ray and neutron shielding properties of CsPbBr3-polypropylene (PP) composite material was investigated in this study. Critical shielding parameters, including linear attenuation coefficient μ, mass attenuation coefficient μm, half-value thickness, tenth-value layer, and mean free path (MFP), were calculated using Phy-X/PSD software. Additionally, two types of gamma-ray buildup factors, i.e., exposure buildup factor and energy absorption buildup factor, were computed within the range of 0.015 to 15 MeV for depths up to 40 MFP. Furthermore, the neutron shielding ability was evaluated by determining the neutron total effective removal cross section. The results demonstrate that the incorporation of CsPbBr3 enhances the gamma-ray and neutron shielding characteristics of the CsPbBr3-PP composite material.

Next-to-leading-order relativistic and QCD corrections to prompt pair photoproduction at future colliders* *Supported in part by the German Research Foundation DFG through Research Unit FOR 2926 "Next Generation Perturbative QCD for Hadron Structure: Preparing for the Electron-Ion Collider" (409651613). The work of X.B.J. was supported in part by National Natural Science Foundation of China (12061131006). The work of R.L. was

Within the framework of nonrelativistic-QCD factorization, we calculate both the next-to-leading-order relativistic and QCD corrections to prompt pair production, with feed-down from mesons, via photon-photon collisions at future colliders, including the Future Circular Lepton Collider (FCC-ee), the Circular Electron Positron Collider (CEPC), and the Compact Linear Collider (CLIC). We present total cross sections and distributions in single transverse momentum and rapidity, as well as in pair invariant mass. The relativistic and QCD corrections both turn out to be large and negative. However, the production rates are large enough for useful experimental studies.

Investigation of the scalar unparticle and anomalous couplings at muon colliders in final states with multiple photons in the Randall–Sundrum model

The influence of the scalar unparticle and anomalous couplings at muon colliders in final states with multiple photons in the Randall–Sundrum model is evaluated in detail. The results indicate that with fixed collision energies, the total cross-sections for the production of multiple photons depend strongly on the polarization of the muon beams, the parameters of unparticle physics (the scaling dimension [Formula: see text], operator [Formula: see text], the energy scale [Formula: see text]) and also the strength of anomalous couplings. Numerical evaluation shows that the cross-sections for the production of four photons in finale states with the contribution of scalar anomalous couplings are much larger than that of the unparticle under the same conditions. In the Higgs–radion mixing, the cross-sections achieve the maximum value at the radion-dominated state, [Formula: see text][Formula: see text]GeV, in which the cross-section is much enhanced and can be measurable in current experiments.

Hint for a Minimal Interaction Length in e+e−⟶γγ Annihilation in Total Cross Section of Center-of-Mass Energies 55-207 GeV

The measurements of the total cross section of the e+e−⟶γγγ reaction from the VENUS, TOPAS, OPAL, DELPHI, ALEPH, and L3 collaborations, collected between 1989 and 2003, are used to perform a χ2 test to validate the current quantum electrodynamics (QED) theory and search for possible deviations with the direct contact term annihilation. By observing a deviation from the QED predictions on the total cross section of the e+e−⟶γγγ reaction above s=180.0 GeV, a non-QED direct contact term is introduced following the dimension 6 effective theory to explain the deviation. In the non-QED direct contact term, a threshold energy scale Λ is included and explained to the finite interaction length in direct contact term and in consequence the size of the electron involved in the annihilation area. The experimental data of the total cross section is compared to the QED cross section by a χ2 test, which gives a best fit of the Λ to be 1576±202 GeV, corresponding to a finite interaction length of re=1.25±0.16×10−17 (cm). In the direct contact term annihilation, this interaction length is a measure of the size of an electron re. By combining all the data results from the mentioned collaborations, we have at least 2 to 3 times more statistics than every single experiment at high s region. This induces the best precision on re compared to the previous measurements.

Cross section sensitivity to perturbation strengths in distorted waves for double electron capture by alpha particles from helium targets

Computer experiments are performed on total cross sections for capture of both electrons from helium targets at 100-10000 keV. Employed are four quantum-mechanical perturbative four-body distorted wave methods (one of the first and three of the second order). The goal is to determine the cross section sensitivity to the perturbation strengths in distorted waves from the second-order methods. The perturbation strength is parametrized by the Sommerfeld factor (the quotient of the nuclear charge and the relative velocity of the colliding particles). At each fixed impact energy, the sought sensitivity is monitored by gradually modifying the nuclear charges in the Sommerfeld factors. These factors reside in the Coulomb distortions of the unperturbed channels states. The focus is on the electronic distortions through the eikonal Coulomb logarithmic phases and the full Coulomb waves. The logarithmic phases are the constituents of the compound phases for the net charges of the two heavy scattering aggregates in relative motions. A striking perturbation strength sensitivity of the obtained total cross sections is recorded.

Production pair of higher excited massive quarkonium at super Z factory

Abstract Sizable amounts of massive quarkonium events should be produced through $Z^0$ boson decays at a future super $Z$ factory. Such channels will provide a suitable platform to study the precisely properties of massive quarkonium. We show that sizable amounts of events for pair of the higher excited states quarkonia can also be produced at the super Z factory. Therefore, we make a further study on calculate the exclusive production of pair of the higher excited charmonium, pair of the higher excited bottomonium, and pair of the higher excited $B_c$ mesons via $e^+e^-\to Z^0 \to |(Q\bar{Q^\prime})[n]\rangle + |(Q^\prime \bar{Q})[n']\rangle$ ($Q,~Q^\prime=c$- or $b$-quarks) at the future $Z$ factory under the NRQCD, where the $[n]$/$[n^\prime]$ represents the color-singlet states $[n^1S_0], [n^3S_1],~[n^1P_1]$, and $[^3P_J]$ ($[n]=1,2,3;J=0,1,2$).
The differential angle distribution of cross sections $d\sigma/dcos\theta$ is given. For a sound estimate,
we discus the uncertainties of total cross sections caused by varying quark masses and the renormalization scale $\mu$. The numerical results show that the future super $Z$ factory should be also a good platform to study the exclusive production of pair of the higher excited massive quarkonium.

Light quark mediated Higgs boson production in association with a jet at the next-to-next-to-leading order and beyond

We study the light quark effect on the Higgs boson production in association with a jet at the LHC in the intermediate transverse momentum region between the quark and the Higgs boson mass scales. Though the effect is suppressed by the small Yukawa coupling, it is enhanced by large logarithms of the quark mass ratio to the Higgs boson mass or transverse momentum. Following a remarkable success of the logarithmic expansion [40] for the prediction of the next-to-next-to-leading bottom quark contribution to the total cross section of the Higgs boson production we extend the analysis to its kinematical distributions. A new factorization formula is derived for the light quark mediated gg → Hg amplitudes and the differential cross section of the process is computed in the logarithmic approximation, which is used for an estimate of the bottom quark effect at the next-to-next-to-leading order.

Quantum scattering in a wavy circle

We study the non-relativistic quantum mechanical scattering problem of a plane-wave by a Chebyshev particle in two spatial dimensions. The Chebyshev particle is a wavy, or undulating, circle. We formulate the problem using the Lippmann–Schwinger (LS) equation and the Chebyshev particle as a boundary-wall potential. This potential is naturally symmetric as a function of the so-called undulation parameter, and we use these symmetries to solve the LS equation and calculate three important physical quantities: the differential cross-section, the total cross-section and the quantum refractive index. We analyze these quantities as functions of the wave number k, the coupling strength γ as well as the undulation and deformation parameters of the Chebyshev particle.

Enhancement of Gamma-Ray and Neutron Shielding Properties of TeO2-Li2O-ZnO-Nb2O5 Glass System with the Addition of Sm2O3

Radiation shielding glass is widely used, as it protects people from ionizing radiation while allowing for the observation of irradiated areas. However, the performance of even the best-performing tellurite glass for radiation shielding still falls short compared to traditional radiation shielding materials. The effect of Sm2O3, with a high atomic number and cross section with neutron, on the gamma-ray and neutron shielding properties of a 75TeO2-5Li2O-10ZnO-(10-x)Nb2O5-(x)Sm2O3 glass system is studied in this work. Some critical shielding parameters, including linear attenuation coefficients, half-value thickness, tenth-value layer, and mean free path (MFP), have been calculated with the software Phy-X/PSD. Two kinds of gamma-ray buildup factors, the exposure buildup factor and the energy absorption buildup factor, have been calculated in the range of 0.015 to 15 MeV for depths up to 40 MFP. What’s more, their neutron shielding ability has been evaluated by calculating the neutron total effective removal cross section. It is shown that Sm2O3 promotes the gamma-ray and neutron shielding performance of the 75TeO2-5Li2O-10ZnO-10Nb2O5 glass system. The results indicate that the addition of Sm2O3 can be helpful for the radiation shielding performance of tellurite glass, which provides a practical way for designing glass with ideal shielding properties.

Forward proton measurements with ATLAS

The ALFA subdetector is designed to measure elastic proton-proton scattering from which the total cross section and \rhoρ-parameter are determined. In 2016, special runs at a center-of-mass energy of \sqrt{s}s = 13 TeV and with \beta^\starβ⋆ = 2.5 km were recorded.

Higgs boson pair production and decay at NLO in QCD: the bb¯γγ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ b\\overline{b}\\gamma \\gamma $$\\end{document} final state

The Higgs boson pair production at the LHC provides a probe to the Higgs boson self-coupling. The higher-order QCD corrections in this process are sizable and must be taken into account in comparison with data. Due to the small cross section, it is necessary to consider at least one of the Higgs bosons decaying to bottom quarks. The QCD corrections to the decay processes would also be important in such cases. We present a full calculation of the total and differential cross sections for the bb¯γγ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ b\\overline{b}\\gamma \\gamma $$\\end{document} final state with next-to-leading order (NLO) QCD corrections. After applying typical kinematic cuts in the final state, we find that QCD NLO corrections in the decay decrease the LO result by 19% and reduce the scale uncertainties by a factor of two. The QCD corrections to the invariant mass mjjγγ distribution, the transverse momentum spectra of the leading bottom quark jet and photon are significant and can not be approximated by a constant factor.

The Astrochemistry Low-energy Electron Cross-Section (ALeCS) database

Context. Electron–molecule interaction is a fundamental process in radiation-driven chemistry in space, from the interstellar medium to comets. Therefore, knowledge of interaction cross sections is key. There have been a plethora of both theoretical and experimental studies of total ionization cross sections spanning from diatomics to complex organics. However, the data are often spread over many sources or are not public or readily available. Aims. We introduce the Astrochemistry Low-energy Electron cross-section (ALeCS) database. This is a public database for electron interaction cross sections and ionization rates for molecules of astrochemical interest. In particular, we present here the first data release, comprising total ionization cross sections and ionization rates for over 200 neutral molecules. Methods. We include optimized geometries and molecular orbital energies at various levels of quantum chemistry theory. Furthermore, for a subset of the molecules, we have calculated ionization potentials. We computed the total ionization cross sections using the binary-encounter Bethe model and screening-corrected additivity rule, and we computed ionization rates and reaction network coefficients for molecular cloud environments. Results. We present the cross sections and reaction rates for >200 neutral molecules ranging from diatomics to complex organics, with the largest being C14H10. We find that the screening-corrected additivity rule cross sections generally significantly overestimate experimental total ionization cross sections. We demonstrate that our binary-encounter Bethe cross sections agree well with experimental data. We show that the ionization rates scale roughly linearly with the number of constituent atoms in the molecule. Conclusions. We introduce and describe the public ALeCS database. For the initial release, we include total ionization cross sections for >200 neutral molecules and several cations and anions calculated with different levels of quantum chemistry theory, the chemical reaction rates for the ionization, and network files in the formats of the two most popular astrochemical networks: the Kinetic Database for Astrochemistry, and UMIST. The database will be continuously updated for more molecules and interactions.

SET sensitivity of a VCRO-based PLL for HL-LHC ATLAS HGTD

We report the characterization of the Single Effect Transient (SET) sensitivity of an analogue Phase Locked Loop (PLL) based on a Voltage Controlled Ring Oscillator (VCRO) under a proton beam. The clock generator is embedded in a front-end ASIC, namely ALTIROC designed in CMOS 130 nm, reading out Low-Gain Avalanche Diode (LGAD) matrices for the High-Luminosity Large Hadron Collider (HL-LHC). We detail the methodology developed to study such events that could degrade the targeted time resolution of 35 ps per hit. Observed SET-induced phase jumps allow the estimation of the total cross-section of the PLL. The results are extrapolated to the HL-LHC radiation conditions.

Quasinormal modes, temperatures and greybody factors of black holes in a generalized Rastall gravity theory

We introduce a modification in the energy-momentum conservation violating Rastall’s theory of gravity and obtain a Reissner-Nordström-type black hole solution in spacetime surrounded by a cloud of strings and charge fields. We examine the horizons of the black hole along with the influence of the parameters of the model on it. The scalar quasinormal modes (QNMs) of oscillations of the black hole are also computed using the 6th order WKB approximation method. It is seen that the Rastall parameter β and the newly introduced energy-momentum tensor trace parameter α as well as the charge parameter q and strings field parameter a influence the amplitude and damping of the QNMs. From the metric function, we obtain the temperature of the black hole and study the effects of the four model parameters β, α, q and a on the temperature. We then examine the greybody factors associated with the black hole and the corresponding total absorption cross-section for it. It is seen that the modification we introduced in the Rastall theory has a drastic effect on various properties of the black hole and may lead to interesting outcomes in future when better detection techniques will be available with the LISA and the Einstein Telescope.

Xenon photonuclear cross sections for the production of 123I radionuclide

A simple reliable theoretical model for the calculation of total photo-absorption cross sections by atomic nuclei has been presented and applied it to get the relevant data needed for the evaluation of the production rate of 123I radionuclide isotope. Since experimental measurements are not available, the model calculation represents the only source of information. The present results, based on an accurate model of nuclear structure, are in very good agreement with the observed photoabsorption cross sections of Te isotopes, which provide reliable cross sections for the neighboring Xe nuclei, where the usual simple estimates are clearly discordant.

Determination of Some Atomic Parameters for Aktaş, Çıldır Lake, and Kura River Water with the Help of WinXCom

In this study, elemental analyses of water samples taken from Aktaş, Çıldır Lake, and Kura River basins in Ardahan province were carried out using Inductively Coupled Plasma Mass Spectrometry. The mass attenuation coefficients, total photon interaction cross sections, effective atomic numbers, and electron densities were determined with the help of WinXCom for the main gamma-ray energies released when Ra-226, which is an important source of natural radiation, decays into Rn-222, Bi-214, and Po-214.

Generation of thermal neutron scattering data for GH3535 alloy

Recent studies related to the thermal neutron scattering (TNS) data in reactors were generally focused on fuels and moderators, while the TNS data for structural materials has received little attention. The TNS effect of the GH3535 alloy, a nickel-based alloy widely used in molten salt reactor (MSR), is studied in this work. The partial phonon densities of states (PDOS) for the main metals (Ni, Mo, Cr and Fe) in the alloy, which are required for the TNS data generation, are calculated using the density functional perturbation theory (DFPT) based on a special quasi-random structure (SQS) of the alloy. The TNS cross sections for the main metals in the alloy are generated using the modified NJOY code. To preliminarily validate the TNS data, the calculated scattering cross section, combined with the evaluated absorption cross section of the alloy, is compared with the experimental total cross section, which shows a good agreement. Moreover, an integral neutronics experiment of neutron leakage spectrum is designed to further validate the TNS data. The neutron leakage spectrum is simulated by the Monte Carlo method, which can be compared with the future experimental result. Based on the experiment geometry modeling, the TNS effects of the GH3535 alloy are analyzed at multiple incident neutron energies, sample thicknesses and temperatures, respectively. It is found that the TNS effect of the GH3535 alloy on the neutron leakage spectrum cannot be ignored, and the scattering cross section of the alloy with high precision should be included in designs of MSR.