Narrow Results

The elastic scattering and reaction cross-sections of ${}^{14}$Be + ${}^{12}$C are analyzed within the microscopic Coulomb modified Glauber model (CMGM), which is a free-parameters model including finite range and Pauli effects. A 2-parameter Fermi (2pF) shape is assumed to describe the nuclear densities. A modified sd (msd) harmonic oscillator model density, which includes core and halo structure with different widths to describe ${}^{14}$Be, is also introduced. For msd-density two configurations, a ${}^{12}$Be-core plus 2n-halo and a ${}^{10}$Be-core plus 4n halo, are assumed. The 2pF with extended neutron tail, as well as the msd-density with core and halo structure, successfully describes both the differential and reaction cross-sections. The extracted rms radius of ${}^{14}$Be by the extended 2pF and msd densities are found to be $3.14\pm 0.03$fm. The calculated reaction cross-sections by these densities at 56MeV/u are found to be 1578–1581.5mb, in consistent data. The differences between the extended 2pF and msd densities in the extracted radii, as well as in the prediction of the reaction cross-section at 56MeV/u, are found to be less than 1$\%$.

Energy-momentum-dependent potentials corresponding to a separable nonlocal and a local potential are constructed to investigate nucleon-nucleus systems. With this interaction, the elastic phase shifts for the $\alpha$-n and $\alpha$-p collisions are calculated within the equivalent potential model. Without further adjustment, a good agreement with experimental data is obtained with a small model space. Additionally, the scattering cross-sections are computed using the partial wave phase parameters.

The phase shift analysis for position location of the resonance at 1.5 MeV was carried out on the basis of the known experimental measurements of the excitation functions of the p¹⁴C elastic scattering at four angles from 90° to 165° and more than 100 energy values in the range from 600–800 keV to 2200–2400 keV. Also, the possibility to describe the available experimental data on the astrophysical S-factor for the proton capture reaction on ¹⁴C to the ground state (GS) of ¹⁵N at astrophysical energies was considered in the frame of modified potential cluster model (MPCM).

In a wide class of potentials, the exact asymptotic dependence on finite distance R from scattering center is established for outgoing differential flux. It is shown how this dependence is eliminated by integration over solid angle for total flux, unitarity relation, and optical theorem. Thus, their applicability domain extends naturally to the finite R.

The thermofield dynamics, a real-time formalism for finite temperature quantum field theory, is used to calculate the rates for e⁺e^- reactions at finite temperature. The results show the role of temperature in defining a hadronic state after the plasma has been cooled down.

This paper reviews the concept of Lorentz invariant relative velocity that is often misunderstood or unknown in high energy physics literature. The properties of the relative velocity allow to formulate the invariant flux and cross-section without recurring to nonphysical velocities or any assumption about the reference frame. Applications such as the luminosity of a collider, the use as kinematic variable, and the statistical theory of collisions in a relativistic classical gas are reviewed. It is emphasized how the hyperbolic properties of the velocity space explain the peculiarities of relativistic scattering.

We study the composite electron production at the FCC-based three electron–proton colliders with the center-of-mass energies of 3.46, 10 and 31.6 TeV. For the signal process of $ep\to e^{\star }X\to e\gamma X$, the production cross-sections and decay widths of the excited electrons have been calculated. The differences of some kinematical quantities of the final state particles between the signal and background have been analyzed. For this purpose, transverse momentum and pseudorapidity distributions of electron and photon have been obtained and the kinematical cuts for discovery of the excited electrons have been assigned. We have finally determined the mass limits of excited electrons for observation and discovery by applying these cuts. It is shown that the mass limit for discovery obtained from the collider with $\sqrt{s}=31.6$ TeV (called PWFA-LC⊗FCC) is 22.3 TeV for the integrated luminosity $L_{\mathrm{\text{int}}}=10{\mathrm{\text{fb}}}^{-1}$.

Cross-sections for positron-rubidium (³⁷Rb) scattering have been calculated using the Clementi–Roetti wavefunctions and a combination of the coupled-static and frozen-core approximations. The total cross-sections, calculated with eight partial waves corresponding to the total angular momentum ℓ=0 to ℓ=7, are determined over a wide region of scattering energies ranging from 2.7 to 300 eV. The resulting total cross-sections are compared with experimental results and those calculated by other authors. Our total collisional cross-sections display a pronounced peak at 5 eV, nearly consistent with the measurements of Parikh et al. [Phys. Rev. A47, 1535 (1993)] and also reveal another peak at 7 eV, consistent with the experimental cross-section of Stein et al.²³ in the neighborhood of 7 eV. The oscillating behavior of our total collisional cross-sections supports the possible existence of resonance, especially at low energy region. The effect of positronium formation on the total collisional cross-sections diminishes when the incident energy is larger than 100 eV.

We classify - and -cross-sections of wreath products of finite inverse symmetric semigroups up to isomorphism. We show that every isomorphism of cross-sections of is a conjugacy. As an auxiliary result, we get that every isomorphism of cross-sections of is also a conjugacy. We also compute the number of non-isomorphic cross-sections of .

Isomeric state excitation in the ¹²⁰Te(γ,n)^119m,gTe reaction within the 10–20 MeV energy range has been studied with bremsstrahlung beams. Energy dependences of experimental isomeric yields ratios and reaction cross-sections have been obtained. Experimental results are compared with TALYS-1.2 calculations.

The continued interest in the study of radiative neutron capture on atomic nuclei is due, on the one hand, to the important role played by this process in the analysis of many fundamental properties of nuclei and nuclear reactions, and, on the other hand, to the wide use of the capture cross-section data in the various applications of nuclear physics and nuclear astrophysics, and, also, to the importance of the analysis of primordial nucleosynthesis in the Universe. This paper is devoted to the description of results for the processes of the radiative neutron capture on certain light atomic nuclei at thermal and astrophysical energies. The consideration of these processes is done within the framework of the potential cluster model (PCM), general description of which was given earlier. The methods of usage of the results obtained, based on the phase shift analysis intercluster potentials, are demonstrated in calculations of the radiative capture characteristics. The considered capture reactions are not part of stellar thermonuclear cycles, but involve in the basic reaction chain of primordial nucleosynthesis in the course of the Universe formation.

Single charge transfer process in collision of energetic protons with molecular hydrogens is theoretically studied using a first-order two-effective-center Born approximation. The correct boundary conditions are incorporated in the formalism and the Hartree–Fock molecular wave function for molecular targets and the residual ions are used to calculate the transition amplitude. The interference patterns in the capture differential cross-sections (DCSs) for a given fixed orientation of the molecule, due to the scattering from the two-atomic centers in the molecular targets, are examined. The dependence of the DCSs upon the angle between the molecular axis and the direction of the incident velocity is theoretically investigated. Both average differential and integral cross-sections are calculated. The obtained results are compared with the available experimental data.

The properties of quantum chromodynamics (QCD) nowadays are accessible by lattice QCD calculations at vanishing quark chemical potential ${\mu }_q=0$, but often lack a transparent physical interpretation. In this review, we report about results from an extended dynamical quasiparticle model (DQPM${}^{\ast }$) in which the effective parton propagators have a complex self-energy that depends on the temperature $T$ of the medium as well as on the chemical potential ${\mu }_q$ and the parton three-momentum $p$ with respect to the medium at rest. It is demonstrated that this approach allows for a good description of QCD thermodynamics with respect to the entropy density, pressure, etc. above the critical temperature $T_c\approx$ 158 MeV. Furthermore, the quark susceptibility ${\chi }_q$ and the quark number density $n_q$ are found to be reproduced simultaneously at zero and finite quark chemical potential. The shear and bulk viscosities $\eta ,\zeta$, and the electric conductivity ${\sigma }_e$ from the DQPM${}^{\ast }$ also turn out in close agreement with lattice results for ${\mu }_q$ =0. The DQPM${}^{\ast }$, furthermore, allows to evaluate the momentum $p$, $T$ and ${\mu }_q$ dependencies of the partonic degrees of freedom also for larger ${\mu }_q$ which are mandatory for transport studies of heavy-ion collisions in the regime 5GeV $<\sqrt{s_{NN}}<$ 10GeV. We finally calculate the charm quark diffusion coefficient $D_s$ – evaluated from the differential cross-sections of partons in the medium for light and heavy quarks by employing the propagators and couplings from the DQPM – and compare it to the available lattice data. It is argued that the complete set of observables allows for a transparent interpretation of the properties of hot QCD.

We have performed a detailed partial-wave analysis in order to analyze each partial-wave contribution to the breakup cross-sections as well as multipole interference effects in the ${}^6\mathrm{\text{Li}}+{}^{152}\mathrm{\text{Sm}}$ breakup reaction. The results show that $d$-waves contribute up to 67.03% of the overall integrated total breakup cross-section, distributed as follows: 10.43% for the $1^{+}$ partial-wave, 21.94% for the $2^{+}$ partial-wave and 34.66% for the $3^{+}$ partial-wave. A similar trend is observed for both Coulomb and nuclear breakup cross-sections. The importance of $d$-waves over the non-$d$-waves in the breakup process is mainly due to the higher-order multipole interferences. It is also obtained that the combination of $d$-waves and $s$-waves accounts for 84.77%, 89.95% and 73.58% of the total, Coulomb and nuclear breakup cross-sections, respectively. Considering the results obtained for the $1^{+}$ and $2^{+}$ partial-waves, we conclude that the $1^{+}$ and $2^{+}$ resonant breakup cross-sections, which can be obtained by integrating over the resonant energy range, could not be negligible compare to the $3^{+}$ resonant breakup cross-section. As far as this reaction is concerned, we can conclude that in the sequential breakup of ${}^6\mathrm{\text{Li}}$, excitations to all its three resonant states should be considered for a fair description of such process.

The systematics of neutron-induced reactions at 14.5MeV are of great importance to describe the excitation of nuclei for the $(n,p)$ reactions. In this study, a new empirical formula is obtained by introducing the proton separation energy to the principal empirical formula for estimating the $(n,p)$ reaction cross-sections for 77 nuclei in the light element mass number range $19\le A\le 101$ at the incident neutron energy of 14.5MeV. The calculated results are compared with the evaluated data declared by the TENDL nuclear data library. The predictions of our formula reveal better agreement with the experimental data than the results obtained from the previous suggested formulae.

Neutrinos ($\nu$) are produced in practically all extragalactic astrophysical processes. They can travel enormous distances from remote parts of the universe at velocities near the speed of light. The interaction of neutrinos with both galactic and extragalactic particles may shed light on the composition of these particles. Dark matter (DM) is perhaps the most favored candidate for such intra- and extragalactic media. In this paper, we study the interaction of neutrinos with cold leptonic DM at the relativistic level. We have calculated cross-sections for the $\nu$–DM interactions by adopting different models for the DM distribution, in order to test DM properties.

New empirical formulae for calculating the $(n,p)$ reaction cross-sections were obtained by using the EXFOR experimental data for the neutron energy 14–15MeV. Considering the average binding energy per nucleon and dependences of cross-section in the principal formula, we get empirical formulae for estimating the $(n,p)$ reaction cross-sections for 122 nuclei in the mass number range of $18\le A\le 205$. The EMPIRE 3.2 and TALYS 1.95 codes have been used to evaluate the $(n,p)$ cross-sections for the selected nuclei within the specified neutron energy. The comparison of calculated cross-sections from the present proposed formulae with those from codes and previous systematics reveals more accurate predictions of the experimental data.

We explored $\gamma$-ray mean lifetimes of transitions $2^{+}\to 0^{+}$ state suggested by earlier researchers such as Grodzins [Phys. Lett. 2 (1962)], Bohr and Mettelson [Mat. Fys. Medd. Dan. Vid. Selsk 27 (1953) 1], Wang’s formula [Chin. J. Phys. 18 (1980) 151], and best global fit formulae [Phys. Rev. C 37 (1988) 805], equations accessible in the literature for nuclei ranging from ${}^{128}$Ce to ${}^{252}$Fm. Also, as compared to other equations accessible in the literature, the standard deviation observed utilizing Grodzins formula with regard to experiments was lower. We also forecasted $\gamma$-ray mean lifetimes of transitions $2^{+}\to 0^{+}$ state and $B(E2)$-values for nuclei ranging from ${}^{122}$Ce to ${}^{256}$Fm. Around 136 even–even nuclei’s mean lifetimes and $B(E2)$-values are predicted which are helpful in the Coulomb fission process.

The analysis of nucleon–nucleon elastic and inelastic scattering data is presented by considering the combined interaction of nuclear and electromagnetic potentials of equal range. The exact analytical off-shell solutions of the nonrelativistic Schrödinger equation for the effective potential with the centrifugal term are investigated using ordinary differential equation approach. Numerical results of scattering phase shifts, differential cross-sections and Transition matrices are in sensible conformity with previous works.

In this paper, we investigated every potential scenario for selenium-induced heavy ion fusion reactions using astatine isotopes as the target. In this context, we examined ${}^{74,76-80,82}$Se projectiles and ${}^{209-211}$At targets having longer half-lives of comprising 21 fusion reactions for the synthesis of superheavy element $Z=119$. We assessed fusion cross-sections (${\sigma }_{fus}$), compound nucleus formation probability ($P_{CN}$), and survival probability ($P_{sur}$) for ${}^{74,76-80,82}$Se projectiles on ${}^{209-211}$At targets. The evaporation residue cross-sections (${\sigma }_{ER}$) is found to be larger for the fusion reaction of ${}^{82}\mathrm{\text{Se}}+{}^{210}$At of about 14.1fb. Hence, these striking results are useful in the synthesis of superheavy element $Z=119$.