Values Of Total Cross Sections Research Articles

Electroweak superpartner production at 13.6 Tev with Resummino

Due to the greater experimental precision expected from the currently ongoing LHC Run 3, equally accurate theoretical predictions are essential. We update the documentation of the Resummino package, a program dedicated to precision cross section calculations for the production of a pair of sleptons, electroweakinos, and leptons in the presence of extra gauge bosons, and for the production of an associated electroweakino-squark or electroweakino-gluino pair. We detail different additions that have been released since the initial version of the program a decade ago, and then use the code to investigate the impact of threshold resummation corrections at the next-to-next-to-leading-logarithmic accuracy. As an illustration of the code we consider the production of pairs of electroweakinos and sleptons at the LHC for centre-of-mass energies ranging up to 13.6 TeV and in simplified model scenarios. We find slightly increased total cross section values, accompanied by a significant decrease of the associated theoretical uncertainties. Furthermore, we explore the dependence of the results on the squark masses.

Contribution of near-edge processes to the L X-ray emission lines for various lanthanum (III) compounds

The present measurement illustrates the study of near-edge processes and the intensity ratios [ILl/ILα, ILβ1/ILα and ILl/ILβ1] for Mn Kα1,2 X-rays across the L2 edge of lanthanum in its various chemical forms viz., lanthanum oxide (La2O3), lanthanum oxalate (C6La2O12) and lanthanum acetate (C6H9LaO6) at four different scattering angles i.e. 90°, 105°, 115° and 125° with a lab-scale X-ray fluorescence (XRF) spectrometer. The current observation reveals that the Lβ1 X-ray emission lines exhibit a variance of ∼ (21–40) % between measured and calculated fluorescence cross-sections. Apart from this, the measured values of intensity ratios have been compared with the three data sets of calculated values using L shell emission rates based on the Dirac-Fock (DF) model, total X-ray emission rates and photoionization cross-section values based on the relativistic Hartree-Slater (RHS) model and three sets of Coster-Kronig (CK) and fluorescence yields. The correlation between crystal structure, bond distance and intensity ratio are also discussed in this work.

Study of Electron Impact Ionization Cross-Sections of Nitrogen Molecule by Inelastic Collision

In this article, the calculation of ionization cross-section of N2 molecule by electron impact is reviewed. The work on ionization cross-sections from threshold to high (10 KeV) incident electron energies are calculated and their applications are discussed. To find exact values of total ionization cross-sections for the N2 molecule, a semiempirical approach of Jain and Khare (1976) is adopted which is a modification to eliminate the error factors, and then it is compared with the existing experimental and/or theoretical data which gives satisfactory results

A study on radiation shielding potentials of green and red clayey soils in Turkey reinforced with marble dust and waste tire

The increasing radiation applications in our daily life makes it essential to protect ourselves from the harms of radiation by using alternative, cheap and natural materials. The present study aimed to analyze the radiation shielding abilities of green and red clayey soils from Oltu/Erzurum in Turkey, reinforced with waste tires and marble dust. For the purpose to investigate the shielding features of the samples, radiation attenuation parameters were determined by using EpiXS software, which can calculate partial or total cross-sections, partial or total mass attenuation coefficients, electron densities, effective atomic numbers, and buildup factors for energy absorption and exposure between 1keV and 1GeV. We compared the obtained mass attenuation coefficients and total atomic cross-section values of the samples with those of a widely used shielding material, ordinary concrete, to make a meaningful evaluation about the shielding potentials of the samples. To validate obtained values by EpiXS, we also calculated the mass attenuation coefficients of the samples by XCOM code, and compatible results were obtained. Among all the studied clayey soil samples, green clay reinforced with marble dust and waste tire has the highest shielding capability. It can also be mentioned that reinforcement with marble dust and waste tire improves the shielding ability of the clayey soils.

Reckoning of nuclear radiation attenuation capabilities for binary GeO2-Tl2O, GeO2-Bi2O3, and ternary GeO2-Tl2O–Bi2O3 glasses utilizing pertinent theoretical and computational approaches

Abstract In this work, a total of eight thallium germanate, bismuth germanate, and bismuth thallium germanate glasses were explored for nuclear radiation shielding purposes. By employing the WinXCOM dependent Phy-X/PSD program, linear attenuation coefficient (μ) and mass attenuation coefficient (μ/ρ) values have been figured out within γ-ray energy range of 0.015–15 MeV and acquired μ/ρ quantities are in well accord with simulated Geant4 and Penelope codes μ/ρ results, accordingly. Some other relevant γ-ray attenuation parameters like effective atomic number (Zeff), effective electron density (Neff), half-value layer (HVL), tenth-value layer (TVL), and mean free path (MFP) were evaluated with the aid of Phy-X/PSD μ/ρ results. All μ/ρ, Zeff, Neff, HVL, TVL, and MFP parameters rely upon both samples' chemical composition and γ-ray energy. In place of GeO2, the inclusion of Tl2O and/or Bi2O3 in all selected samples demonstrates the enhanced γ-ray attenuation capacity with increasing Zeff and lower HVL, TVL, and MFP values. Besides, utilizing geometric progression (G‒P) fitting approach, within 0.015–15 MeV γ-ray energy range exposure buildup factors (EBFs) and energy absorption buildup factors (EABFs) have been estimated at discrete penetration depths (up to 40 mfp) and larger EBFs and EABFs are attained at higher energies with greater penetration depths. The ternary 16GeO2-62Tl2O–22Bi2O3 (mol%) glass, among all the tested samples, by owing comparatively larger μ, μ/ρ, and Zeff, lower HVL, TVL, MFP, EBFs, and EABFs, validate its' superior γ-ray attenuation ability as even HVL and MFP quantities of this sample are lower than some of the commercial shielding glasses, alloys, polymers, and concretes respective values when compared. Additionally, for all samples, neutron total cross-section (σT) values are derived within the neutron energy range of 10−8‒10 MeV by exerting Geant4 code. At 10−8 and 10 MeV neutron energies, the obtained ‘σT’ values are varied within 0.3589–0.4245 cm−1 and 0.13–0.1439 cm−1 ranges, respectively, for all studied glasses.

Estimation of gamma-rays, and fast and the thermal neutrons attenuation characteristics for bismuth tellurite and bismuth boro-tellurite glass systems

Gamma-rays and fast and thermal neutron attenuation features of (Bi2O3)x–(TeO2)(100−x) (where x = 5, 8, 10, 12, and 15 mol%) and [(TeO2)0.7–(B2O3)0.3](1−x)–(Bi2O3)x (where x = 0.05, 0.10, 0,15, 0.20, 0.25, and 0.3 mol%) glass systems have been explored and compared. For all samples, mass attenuation coefficients (μ/ρ) are estimated within 0.015–15 MeV photon energy range by MCNP5 simulation code and correlated with WinXCom results, which showed a satisfactory agreement between computed μ/ρ values by these both methods. Additionally, effective atomic number (Zeff), effective electron density (Neff), half-value layer (HVL), tenth-value layer (TVL), mean free path (MFP), total atomic cross-section (σa), and total electronic cross-section (σe) are calculated by utilizing μ/ρ values. The μ/ρ, Zeff, and Neff are energy dependent and have higher values at the lowest energy and smaller values at higher energies. Moreover, using the G–P fitting method as a function of penetration depth (up to 40 mfp) and incident photon energy (0.015–15 MeV range), exposure buildup factors (EBFs) and energy absorption buildup factors (EABFs) are evaluated. Both 85TeO2–15Bi2O3 (mol%) and 49TeO2–21B2O3–30Bi2O3 (mol%) samples, by possessing higher values of Zeff, exhibit minimum EBF and EABF values. Highest μ/ρ, Zeff values and lowest HVL, TVL, MFP values of 49TeO2–21B2O3–30Bi2O3 (mol%) sample indicated its better gamma-ray absorption capability among all selected glasses. Further, macroscopic effective removal cross-section for fast neutrons (ΣR), coherent scattering cross-section (σcs), incoherent scattering cross-section (σics), absorption cross-section (σA), and total cross-section (σT) values for thermal neutron attenuation have been computed. Among all samples, 49TeO2–21B2O3–30Bi2O3 (mol%) glass possesses a better ΣR value for fast neutron attenuation, while the largest ‘σT’ value of 66.5TeO2–28.5B2O3–5Bi2O3 (mol%) sample suggests its good thermal neutron absorption efficiency.

Вероятность процессов захвата электронов у атомов аргона ионами -=SUP=-3-=/SUP=-Не-=SUP=-2+-=/SUP=- при различных параметрах удара

AbstractWe have measured the absolute values of total cross sections of capture of one and two electrons by He^2+ ions from argon atoms. The differential scattering cross sections have been determined for fast atoms and singly charged helium ions formed in each of these processes (without and with additional ionization of the formed slow argon ion). Measurements have been taken for He^2+ ions with kinetic energy of 6 keV in scattering angle range 0–2.5°. Based on the measured differential cross sections using different model atomic particle interaction potentials, we have calculated the cross sections of these processes as functions of the impact parameter. The probabilities of realization of these processes with electron density distribution in different shells in the target atom have been compared. The applicability of the expressions for the screened Coulomb interaction potentials in the description of scattering of particles that have captured electrons has been demonstrated.

Nuclear medium effects in muonic neutrino interactions with energies from 0.2 to 1.5 GeV

Nuclear reactions induced by muon neutrino with energies in the range from 0.2 to 1.5 GeV in Monte Carlo calculations framework in the intra-nuclear cascade model are studied. This study was done by comparison between the available experimental data and theoretical values of total cross section, and the energy distribution of emitted lepton energy in the reaction muon neutrino-nucleus, using the targets: $^{12}$C, $^{16}$O, $^{27}$Al, $^{40}$Ar, $^{56}$Fe and $^{208}$Pb. A phenomenological toy model of primary neutrino-nucleon interaction gives a good agreement of our theoretical inclusive neutrino nucleus cross in comparison with the available experimental data. Some interesting results on the behavior of the cross section as function of 1p-1n and higher contributions are also sketched. The previous results on the percentage of fake events related in available experiments in $^{12}$C were expanded for the set studied nuclei. With the increase of mass target, the nuclear effects in the cross sections were observed along with the importance to take into account fake events in the reactions.

Studying total proton–proton cross section collision at large hadron collider using gene expression programming

New technique is presented for modeling total cross section of proton-proton (p-p) collision from low to ultra-high energy regions using gene expression programming (GEP). GEP, as a machine learning technique is usually used for modeling physical phenomena by discovering a new function . In case of modeling the p-p interactions at the Large Hadron Collider (LHC), GEP is used to simulate and predict the total cross-section which is a function of total center-of-mass from low to high energy √s. The discovered function shows a good match as compared with the other models. The predicted values of total cross section are in good agreement with Particle Data Group (PDG).

First results of total and partial cross-section measurements of the 107Ag(p,γ)108Cd reaction

The γ process is assumed to play an important role in the nucleosynthesis of the majority of the p nuclei. Since the network of the γ process includes so many different reactions and - mainly unstable - nuclei, cross-section values are predominantly calculated in the scope of the Hauser-Feshbach statistical model. The values heavily depend on the nuclear-physics input parameters. The results of total and partial cross-section measurements are used to improve the accuracy of the theoretical calculations. In order to extend the experimental database, the 107 Ag(p,γ )108 Cd reaction was studied via the in-beam method at the high-efficiency HPGe γ -ray spectrometer HORUS at the University of Cologne. Proton beams with energies between 3.5 MeV and 5.0 MeV were provided by the 10 MV FN-Tandem accelerator leading to the determination of four new total cross-section values. After slight adjustments of the nuclear level density and γ -ray strength function an excellent agreement between theoretical calculations and experimentally deduced values for both total and partial cross sections has been obtained.

Partial cross sections of theMo92(p,γ)reaction and theγstrength inTc93

Background: Mo92 is the most abundant nucleus of the p nuclei, with an isotopic abundance of more than 14 %. The γ-process nucleosynthesis is believed to produce Mo92 but fails to explain its large abundance, especially with respect to the other p nuclei produced in the same stellar environment. Further studies require precise nuclear models for the calculation of reaction cross sections. Purpose: A measurement of the total and partial cross sections of the Mo92(p,γ)Tc93 reaction allows for a stringent test of statistical-model predictions. Not only different proton+nucleus optical model potentials, but also the γ-ray strength function of Tc93 can be investigated. In addition, high-resolution in-beam γ-ray spectroscopy enables the determination of new precise nuclear structure data for Tc93. Method: Total and partial cross-section values were measured by using the in-beam method. Prompt γ rays emitted during the irradiation of Mo92 with protons at seven different energies between 3.7 and 5.3 MeV were detected by using the high-purity germanium (HPGe) detector array HORUS at the Institute for Nuclear Physics, University of Cologne. The γγ-coincidence method was applied to correlate γ-ray cascades in Tc93 with their origin in the Mo92+p compound state. Results: The measured cross sections are compared to Hauser-Feshbach calculations by using the statistical-model code talys on the basis of different nuclear physics input models. Using default settings based on standard phenomenological models, the experimental values cannot be reproduced. A shell-model calculation was carried out to predict the low-energy M1 strength in Tc93. Together with Gogny-Hartree-Fock-Bogoliubov (Gogny-HFB) or Skyrme-HFB plus quasi-particle random-phase approximation (QRPA) models for the γ-ray strength function, the agreement between experimental data and theoretical predictions could be significantly improved. In addition, deviations from the adopted level scheme were found. Conclusions: By using Gogny- or Skyrme-HFB+QRPA E1 and shell-model M1 strength functions, statistical-model predictions can be significantly improved. Partial cross sections provide a valuable testing ground for γ-ray strength functions for nuclear astrophysics applications. In addition, they can be used to investigate nuclear-structure properties of the compound nucleus.

Measurement of LIII jump ratio, jump factor and related parameters for Pt and Tl

LIII jump ratio, jump factor and its related parameters for Pt and Tl have been measured by using photons of energy 59.54 keV from 241Am source. The measurements are made by using gamma attenuation method in secondary excitation geometry with high resolution (155 eV at 5.9 keV) Si(Li) detector. X-rays energies, above and below the LIII edge for the targets of Pt and Tl are obtained by using secondary target of Br, Co, Cu, Fe, Ga, Ni, Pt, Se, Sr, Tl and Zn. The measurements are compared with the theoretical values of total attenuation cross-sections, LIII Jump ratio, jump factor; Davisson–Krichner ratio and LIII sub-shell oscillator strength obtained by using mass attenuation coefficients from WinXCom. It is observed that the measured values are in good agreement with theoretical results. These measurement shall enhances the understanding of material characteristics of Pt and Tl, as these are widely used in biological, chemical, medical, electronics and petroleum industry.

Total and partial cross sections of theSn112(α,γ)Te116reaction measured via in-beamγ-ray spectroscopy

An extended database of experimental data is needed to address uncertainties of the nuclear-physics input parameters for Hauser-Feshbach calculations. Especially $\alpha$+nucleus optical model potentials at low energies are not well known. The in-beam technique with an array of high-purity germanium (HPGe) detectors was successfully applied to the measurement of absolute cross sections of an ($\alpha$,$\gamma$) reaction on a heavy nucleus at sub-Coulomb energies. The total and partial cross-section values were measured by means of in-beam $\gamma$-ray spectroscopy. Total and partial cross sections were measured at four different $\alpha$-particle energies from $E_\alpha = 10.5$ MeV to $E_\alpha = 12$ MeV. The measured total cross-section values are in excellent agreement with previous results obtained with the activation technique, which proves the validity of the applied method. The experimental data was compared to Hauser-Feshbach calculations using the nuclear reaction code TALYS. A modified version of the semi-microscopic $\alpha$+nucleus optical model potential OMP 3, as well as modified proton and $\gamma$ widths, are needed in order to obtain a good agreement between experimental data and theory. It is found, that a model using a local modification of the nuclear-physics input parameters simultaneously reproduces total cross sections of the $^{112}$Sn($\alpha$,$\gamma$) and $^{112}$Sn($\alpha$,p) reactions. The measurement of partial cross sections turns out to be very important in this case in order to apply the correct $\gamma$-ray strength function in the Hauser-Feshbach calculations. The model also reproduces cross-section values of $\alpha$-induced reactions on $^{106}$Cd, as well as of ($\alpha$,n) reactions on $^{115,116}$Sn, hinting at a more global character of the obtained nuclear-physics input.

Total Charge Changing Cross-Sections of 300 MeV/A Fe26+ Ion Beam in Different Target Media

Total charge changing cross-sections of 300 MeV/A Fe26+ ion beam in Al and combined media of CH2, CR39 and Al were calculated by CR39 track etch detectors using an image analysing system; DM6000M optical microscope attached with a personal computer installed with Leica QWin Plus software. The CR39 nuclear track detectors were used to identify the incident charged particles and their fragments. Exposed CR39 detectors were etched in 6N NaOH solution + 1% ethyl alcohol at 70 ˚C to visualize the tracks produced by primary ion beam and its fragmentations under optical microscope. The temperature was kept constant throughout the etching within ± 0.1˚C. The present work shows better response of the CR39 track etch detector up to an improved threshold Z/β ∼ 4.6. The cone-diameter distributions were fitted by multiple Gaussians using ROOT software analysis toolkit. The numbers of incident and survived ions were determined within 99.7% confidence levels. The calculated values of total charge changing cross-section were (1663 ± 236) mb in Al target, (1219 ± 29) mb in combined target CH2+CR39+Al and (1020 ± 121) mb in combined target CH2+CR39.

Cross-section measurement of theBa130(p,γ)La131reaction forγ-process nucleosynthesis

Background: Deviations between experimental data of charged-particle-induced reactions and calculations within the statistical model are frequently found. An extended data base is needed to address the uncertainties regarding the nuclear-physics input parameters in order to understand the nucleosynthesis of the neutron-deficient $p$ nuclei.Purpose: A measurement of total cross-section values of the $^{130}\mathrm{Ba}(p,\ensuremath{\gamma})^{131}\mathrm{La}$ reaction at low proton energies allows a stringent test of statistical model predictions with different proton+nucleus optical model potentials. Since no experimental data are available for proton-capture reactions in this mass region around $A \ensuremath{\approx}130$, this measurement can be an important input to test the global applicability of proton+nucleus optical model potentials.Method: The total reaction cross-section values were measured by means of the activation method. After the irradiation with protons, the reaction yield was determined by use of $\ensuremath{\gamma}$-ray spectroscopy using two clover-type high-purity germanium detectors. In total, cross-section values for eight different proton energies could be determined in the energy range between 3.6 MeV $\ensuremath{\le}{E}_{p}\ensuremath{\le}$ 5.0 MeV, thus, inside the astrophysically relevant energy region.Results: The measured cross-section values were compared to Hauser-Feshbach calculations using the statistical model codes TALYS and SMARAGD with different proton+nucleus optical model potentials. With the semimicroscopic JLM proton+nucleus optical model potential used in the SMARAGD code, the absolute cross-section values are reproduced well, but the energy dependence is too steep at the lowest energies. The best description is given by a TALYS calculation using the semimicroscopic Bauge proton+nucleus optical model potential using a constant renormalization factor.Conclusions: The statistical model calculation using the Bauge semimicroscopic proton+nucleus optical model potential deviates by a constant factor of 2.1 from the experimental data. Using this model, an experimentally supported stellar reaction rate for proton capture on the $p$ nucleus $^{130}\mathrm{Ba}$ was calculated. At astrophysical temperatures, an increase in the stellar reaction rate of 68% compared to rates obtained from the widely used NON-SMOKER code is found. This measurement extends the scarce experimental data base for charged-particle-induced reactions, which can be helpful to derive a more globally applicable proton+nucleus optical model potential.

Decay studies of59Cu*formed in the35Cl +24Mg reaction using the dynamical cluster-decay model

The reformulated dynamical cluster-decay model (DCM) is applied to study the decay of odd-A and non-$\ensuremath{\alpha}$ structured ${}^{59}{\text{Cu}}^{*}$ formed in the ${}^{35}\text{Cl}+{}^{24}\text{Mg}$ reaction at ${E}_{\text{lab}}=275$ MeV. Here, the temperature ($T$)--dependent binding energies due to Krappe are used. The roles of Wigner and pairing energies in the fragmentation potential are explicitly shown in this work. For the temperature $T=4.1898$ MeV corresponding to ${E}_{\text{lab}}=275$ MeV, the contribution of pairing vanishes and the resulting structure of the fragmentation potential due to Wigner term is shown. In addition to this, we have studied the role of factor $\ensuremath{\alpha}$ appearing in the inertia part of the equation of motion dictating the mass-transfer process. It is shown that this factor has significant effect in the structure of preformation probability values and hence in turn we see significant changes in the cross sections. We compare the cross sections of the measured charge distributions of the fission fragments for two limiting values of the parameter $\ensuremath{\alpha}$ with the experimental data. In order to fit the total cross-section values, a linear relation is obtained between the free parameter of the model $▵R$ and the factor $\ensuremath{\alpha}$ appearing in the hydrodynamical mass.

Amplitudes and observables in pp elastic scattering at $\sqrt{s}=7\ \mbox{TeV}$

A precise analysis of the pp elastic scattering data at 7 TeV in terms of its amplitudes is performed as an extension of previous studies for lower energies. Slopes B R and B I of the real and imaginary amplitudes are independent quantities, and a proper expression for the Coulomb phase is used. The real and imaginary amplitudes are fully disentangled, consistently with forward dispersion relations for amplitudes and for slopes. We present analytic expressions for the amplitudes that cover all t range completely, while values of total cross section σ, ratio ρ, B I , and B R enter consistently to describe forward scattering. It is stressed that the identification of the amplitudes is an essential step for the description of elastic scattering, and pointed out the importance of the experimental investigation of the transition range from non-perturbative to perturbative dynamics, which may confirm the three gluon exchange mechanism observed at lower energies.

Origin of the Larger Values of Total Cross Section for Helium Scattering from Isolated Atomic Steps

The effect of surface relaxation and the electronic re-arrangement in the vicinity of a step on the total step cross section for helium scattering is investigated. A realistic helium interaction potential at a Cu(001) step is modeled by summing non-spherical pair potentials which allows for the possibility of varying the smoothing across the surface due to the itinerant aspects of the surface electronic structure. Numerical calculations reveal a significant increase in the magnitude of the total step cross section with large charge re-arrangement in the vicinity of the step. Also, the relaxation of surface layers has no effect whatsoever. The present study clearly shows that the origin of the experimentally observed large step cross section is the hard wall scattering from charge re-arrangement in the proximity of the step. Further, the charge re-arrangements probed by thermal helium atoms must be greater than predicted by pairwise models.DOI: http://dx.doi.org/10.3329/dujs.v60i2.11532 Dhaka Univ. J. Sci. 60(2): 271-275, 2012 (July)

Elastic cross sections for electron scattering from GeF4: Predominance of atomic-F in the high-energy collision dynamics

We report absolute differential cross sections (DCSs) for elastic electron scattering from GeF(4). The incident electron energy range was 3-200 eV, while the scattered electron angular range was typically 15°-150°. In addition, corresponding independent atom model (IAM) calculations, within the screened additivity rule (SCAR) formulation, were also performed. Those results, particularly for electron energies above about 10 eV, were found to be in good quantitative agreement with the present experimental data. Furthermore, we compare our GeF(4) elastic DCSs to similar data for scattering from CF(4) and SiF(4). All these three species possess T(d) symmetry, and at each specific energy considered above about 50 eV their DCSs are observed to be almost identical. These indistinguishable features suggest that high-energy elastic scattering from these targets is virtually dominated by the atomic-F species of the molecules. Finally, estimates for the measured GeF(4) elastic integral cross sections are derived and compared to our IAM-SCAR computations and with independent total cross section values.

Charge transfer and charge transfer with excitation of a target ion in slow collisions of α particles with helium atoms. II

The cross sections of single- and double-electron capture in 3He2+-He collisions in the energy interval of incident α particles of 3–120 keV were obtained. The cross sections were calculated for the Coulomb trajectory of motion of nuclei in the context of the close-coupling equation method using the basis set of two-electron adiabatic molecular states. Introduction of additional requirements that must be satisfied by the numerical solutions of the system of coupled differential equations made it possible to obtain a good correspondence between the calculated values of total cross sections of single- and double-electron capture and the experimental data in the whole range of the considered collision energies.