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In this paper, we present a detailed analytical computation of the triple differential cross sections, in the first Born approximation, for the relativistic electron-impact ionization of hydrogen atom in the metastable 2S-state in the symmetric and asymmetric coplanar geometries. The process is investigated by using the relativistic Dirac-formalism where the effects of spin and relativity are taken into account. It is shown that the nonrelativistic limit is accurately reproduced when applying low incident kinetic energies. At high energies, relativistic and spin effects are found to significantly affect the triple differential cross sections. The numerical results obtained for the triple differential cross section are compared with some other theoretical results in the nonrelativistic regime for asymmetric coplanar geometry. For this particular process and in the absence of any experimental data and theoretical models at high energies for the triple differential cross sections, the results of our calculated relativistic total cross section are compared with available theoretical and experimental results. We hope that the present study will provide significant contribution to future experiments.

In principle, this paper suggests powerful laser technology as a promising instrument that can be experimentally useful to control the lifetime and branching ratio for an unstable particle decay. In a recent paper [ arXiv:2101.00224 ], we calculated theoretically the W − -boson leptonic decay ( W − → l − ν l ) in the presence of a circularly polarized laser and we showed that the laser significantly contributed to the diminution of the leptonic decay rate. In this paper, as a continuation of the previous one, we mainly deal with the theoretical calculation of the W − -boson hadronic decay ( W − → q q ′ ) and we combine the analytical results obtained in both papers to examine the effect of an intense laser, in terms of its field strength and frequency, on the three measurable quantities in W − -boson decay (total decay rate, lifetime and branching ratios). It was found that the laser has notably contributed to the reduction of the total decay rate leading to a longer lifetime. Most importantly, the two branching ratios (one for leptons and the other for hadrons) are affected (increased or decreased) by the presence of a strong external electromagnetic field. Combined together, these two complementary works may provide an in-depth and comprehensive study that would be useful for any experimental investigation in the future.

In the centre of mass frame, we have studied theoretically the Z -boson resonant production in the presence of an intense laser field via the weak process e + e − → μ + μ − . Dressing the incident particles by a Circularly Polarized laser field (CP-laser field), at the first step, shows that for a given laser field’s parameters, the Z - boson cross section decreases by several orders of magnitude. We have compared the Total Cross Section (TCS) obtained by using the scattering matrix method with that given by the Breit-Wigner approach in the presence of a CP-laser field and the results are found to be very consistent. This result indicates that Breit-Wigner formula is valid not only for the laser-free process but also in the presence of a CP-laser field. The dependence of the laser-assisted differential cross section on the Centre of Mass Energy (CME) for different scattering angles proves that it reaches its maximum for small and high scattering angles. At the next step and by dressing both incident and scattered particles, we have shown that the CP-laser field largely affects the TCS, especially when its strength reaches 1 0 9 V . c m − 1 . This result is interpreted by the fact that heavy interacting particles require high laser field intensities to affect the collision’s cross section.

In the framework of the first Born approximation, we investigate, in the presence of a circularly polarized electromagnetic laser field, the double effect of Coulomb and anomalous magnetic moment (AMM) on the scattering of electron by a fixed atomic nucleus. In this approximation, the initial and final states of the electron are described by the relativistic Coulomb Dirac–Volkov wave functions with AMM effect. For convenience, we choose the origin of the Laboratory coordinate system at the centre of the fixed nucleus presenting a classical Coulomb potential. Both AMM and Coulomb effects on the incident and scattered electrons have affected the relativistic differential cross section. At high energies of the incident electron, our explored numerical results give the predominance of the AMM effect over that of Coulomb. The behavior of the differential cross section, as a function of the electric field strength as well as the laser frequency, is presented.

To determine the incidence rate of seborrheic dermatitis, bullous pemphigoid, rosacea, and melanoma among the patients diagnosed with Parkinson's Disease. A cross-sectional, observational study. From 13th May 2020 to 13th April 2022 at Bahria International Hospital, Lahore, Pakistan. A total of 80 patients with confirmed Parkinson's disease were evaluated for skin disorders. Disease severity was confirmed through Hoehn Yahr staging criteria (H-Y stage). Skin characteristics and disease diagnosis was made through finding sebum production levels, hot/cold flush test, immunofluorescence, and biopsy evaluation for seborrheic dermatitis, rosacea, bullous pemphigoid, and melanoma, respectively. The test results were compared with the control subject. Chi2 and student t-test was used to find the significance of the results. Out of 80, 44 patients were positive for skin disorders. The incidence of seborrheic dermatitis was found in 31.2% of patients whereas rosacea, bullous pemphigoid, and melanoma were found in 15%, 6.2%, and 2.5% of patients, respectively. Skin disorders are highly prevalent among Parkinson’s disease patients than in the control population. The study invites further research in this area so that the quality of life of patients could be improved.

Darwin wave functions, as a quasi-relativistic states describing the hydrogen atom, are used to calculate the differential cross section for inelastic excitation of 2p state hydrogen atom by electronic impact in various electron energy regions. The use of these wave functions gives interesting results so long as the condition $$z/c\ll 1$$ is verified. The incident and scattered electrons are described by a free Dirac spinor. Relativistic spin effects are taken into account explicitly via the spinorial part. The computed results, in the first Born approximation, are given and discussed by analogy with the non-relativistic regime and the relativistic $$1s\rightarrow 2s$$ . They are also compared with some other available theoretical models and with the experimental results of Williams (J Phys B At Mol Phys 14:1197, 1981). The general rule of optically allowed and forbidden transitions is also respected.

Aims: The present study is aimed to determine the role of acceptance and mindfulness therapy on physical activity increment and obesity decrement in the patients suffering from heart disease in Bandar Abbas. Participants & Methods: In terms of type, the study is applied one and in terms of research method, it is a quasi-experimental study along with a pre-test-post-test with a control group. The statistical population of the study involves all the patients suffering from heart disease being overweight who had visited Bandar Abbas’ hospitals during 2018-2019 and according to angiographic reports, eclipse was more than 50% and BMI≥30. In the present study, an available sampling method was used. The population size was 20 that 10 were assigned to experimental group and 10 to control group. The data were collected through making use of physical activity level, body mass index (BMI) questionnaire. Data were analyzed using covariance analysis and SPSS software. Findings: Acceptance therapy had been effective on physical activity increment and body mass decrement of the patients suffering from heart disease. Conclusion: Mindfulness-based therapy can be considered as a non-invasive treatment. This clinical trial will result in more effective mindfulness-based interventions as a complementary treatment in primary care for people with overweight and obesity.

This work aims to study theoretically the electron-proton scattering for initially spin-polarized electrons in the presence of a circularly polarized electromagnetic field. Using the first Born approximation and the Dirac-Volkov states for dressed electrons, we derive an analytic expression for the differential cross-section with the help of the spin-helicity formalism. Meanwhile, a well-known concept of spin-flip and spin non-flip differential cross sections is applied. The influence of the electromagnetic field on the degree of polarization of the scattered electron is investigated, and the effect of electron spin polarization is examined. We found that the initial spin of the electron can be affected depending on its kinetic energy during the scattering process. This work is a continuation of a recent paper in which we studied the unpolarized electron-proton scattering in the presence of a laser field (Dahiri, et al., Laser Phys. Lett. 18 (2021) 096001).

In the framework of Higgs triplet model (HTM), we study the pair production process of doubly charged Higgs bosons via $e^{+}e^{-}$ annihilation in the presence of a laser field with circular polarization . We begin our work by presenting the theoretical calculation of the differential cross section in the centre of mass frame including both $Z$ and $\gamma$ diagrams. Then, from the numerical analysis of the production cross section's dependence on the laser field parameters, we have shown that the laser-assisted total cross section decreases as far as the electromagnetic field intensity enhances or by decreasing its frequency. Finally, we analyze the variation of the total cross section versus the mass of the doubly charged Higgs boson by fixing the laser field parameters and the centre of mass energy, and we have found that the order of magnitude of the cross section decreases as long as $M_{H^{\pm\pm}}$ increases., Comment: 18 pages, 6 figures

The top quark is distinct from all other fermions due to its high mass and short lifetime. Therefore, it decays rapidly almost exclusively into a light quark and a W + gauge boson. Through all of these properties, the top quark can reveal new details about the standard model and possibly about new physics. In this paper, we have investigated the two-body decay of the top quark ( t → q W + ), where q represents one of the quarks d, s and b, in the presence of a monochromatic circularly polarized laser field. Using the lowest-order Dirac-Volkov formalism, we have analytically established the expression for the laser-assisted total decay width of the top quark. We have analyzed the dependence of the total decay width, as well as the lifetime and branching ratios (BRs) on the characteristic parameters of the laser. The results indicate that the laser has a decreasing effect on the decay width, leading to an extension of the lifetime. The lifetime behavior inside the laser field is explained by the quantum Zeno effect. More importantly, we find that the laser field with an appropriate frequency and electric field amplitude leads to a modification of the BRs either by the enhancement of the ( t → b W + ) mode or by the suppression of the ( t → s W + ) and ( t → d W + ) modes.

In the framework of the electroweak standard model, we have investigated the top quarks pair production from e − e + annihilation at the energies of a future compact linear collider in the presence of an intense circularly polarized laser field. We have analytically generated the detailed expression for the laser-assisted differential cross section using the lowest-order Dirac-Volkov formalism, including the γ t t ˉ and Z t t ˉ interactions, in the center-of-mass frame. A wide range of center-of-mass energies corresponding to the future e − e + collider has been covered to study the behavior of the total cross section (TCS); this future compact linear collider constitutes an important direction in the study of top quark physics in order to improve the measurements, and the limits of some physical parameters obtained so far at the LHC and the Tevatron. We have analyzed the dependence of the laser-assisted total and partial cross sections on the energy of the center-of-mass of the colliding system e − e + and also on the parameters of the laser field, such as the number of exchanged photons, the laser field strength, and its frequency. The results indicate that the laser field decreases the order of magnitude of the TCS as much as the laser field strength increases or decreases its frequency.

In view of the great contribution of neutrino-electron scattering to the deep understanding of electroweak interactions, we focus in this paper on the study of elastic scattering of a muon neutrino by an electron $(e^{-}\nu_{\mu}\rightarrow e^{-}\nu_{\mu})$ in the presence of a circularly polarized electromagnetic field. We perform our theoretical calculation within the framework of Fermi theory using the exact wave functions of charged particles in an electromagnetic field. The expression of the differential cross section (DCS) for this process is obtained analytically in the absence and presence of the laser field. The effect of the field strength and frequency on the exchange of photons as well as on the DCS is presented and analyzed. Massive neutrino effects are also included and discussed. This study, added to the previous ones, will significantly enrich our knowledge in fundamental physics., Comment: 14 pages, 3 figures, 3 tables, 65 references, 1 appendix

In this study, we have investigated the two-body hadronic decay of the charged kaon, $ K^{+}\rightarrow\pi^{+}+\pi^{0} $, in the presence of a laser field with circular polarization. We have derived, by analytical techniques, the laser-assisted decay width and the branching ratio of the charged kaon decay via the two-body hadronic channel. We have also taken into consideration the impressive results obtained for the laser-assisted charged kaon decay via the leptonic mode in order to understand more clearly the effect of the laser field on the quantities related to the charged kaon decay such as the decay width, the branching ratio and lifetime. A precise comparison of the ratios of hadronic to muonic decay in the presence of the laser field is made to show that the hadronic mode becomes slightly more important by increasing the laser field intensity., Comment: 13 pages, 4 figures

In this research paper, we have investigated the process of muon pair production in high energy e + e − collisions via the exchange of γ and Z-bosons in the presence of the laser field for different directions. Analytical calculations of the cross-section are done within the scattering matrix approach by using the Dirac-Volkov states for electron and positron. The numerical computation of the cross-section shows that it behaves differently by changing the laser wave direction. For a laser field propagating in parallel with the incident beam, the cross-section is strongly affected from low intensities. In addition, for a given laser field strength and frequency, the required number of photons to be transferred increases by increasing the centre of mass energy. Therefore, the acceleration gradient provided by a collinear laser field further enhances the centre of mass energy.

In accordance with the electroweak theory, we perform a detailed analytical treatment of the differential cross-section (DCS) for the elastic scattering process e − + ν μ ⟶ e − + ν μ in both absence and presence of a circularly polarized laser field. This scattering process is examined, in the first-Born approximation, by using Dirac–Volkov wave functions for charged particles within an external laser field. The theoretical results obtained for the differential cross-section without a laser field are compared with other theoretical results within the framework of Fermi theory. These results revealed to us the importance of using electroweak theory instead of Fermi approximation for studying high energy electroweak interactions. The differential cross section is modified significantly by inserting the electrons into an electromagnetic field. In addition, the influence of the laser strength and its frequency on the photons exchange between the colliding system and the laser field is also included and discussed. These effects are heavily related to the order and argument of the ordinary Bessel functions introduced in the theoretical calculation.

In this paper, we have theoretically studied the neutral Higgs pair production in Two Higgs Doublet Model (THDM) in the presence of a circularly polarized laser field. The laser-assisted differential partial cross section is derived in the centre of mass frame at the leading order including $Z$ diagram. The total cross section is computed numerically by integrating the differential cross section over the solid angle $d\Omega$. Two benchmark points are discussed for the THDM parameters. In the first step, we have analyzed the total cross section of ${e}^{+}{e}^{-}\rightarrow h^{0}A^{0}$ by considering $H^{0}$ as the standard model-like Higgs boson. Then, the process ${e}^{+}{e}^{-}\rightarrow H^{0}A^{0}$ is studied by taking $h^{0}$ as the Higgs boson of the standard model. For both benchmark points, the laser-assisted total cross section of the studied processes depends on the produced neutral Higgs masses, the centre of mass energy and the laser field parameters. In addition, the maximum cross section occurs at high centre of mass energy for the process ${e}^{+}{e}^{-}\rightarrow H^{0}A^{0}$ as compared to that of ${e}^{+}{e}^{-}\rightarrow h^{0}A^{0}$., Comment: 18 pages, 10 figures

The full one-loop corrections, both the weak and QED corrections, to the process $e^+ e^- \to Z \phi $ ($\phi=h^0,H^0$) in the two Higgs doublet model (2HDM) at the Higgs factories are presented. Up to the $O(\alpha_{em})$ level, the virtual corrections are evaluated by using the FeynArts/FormCalc packages. The real emission corrections are computed using the Feynman Diagram Calculation (FDC) package and the collinear divergences are regularized by the structure functions of an electron. Using the FeynArts/FormCalc and the FDC packages, we study the corrections in the Standard Model (SM) and the 2HDM, respectively. Gauge dependence arising in the normalization of mixing angles is removed by using the pinch technique. After taking into account experimental constraints from the current LHC data, we propose four interesting benchmark scenarios for future colliders. By using these benchmark scenarios, we evaluate the deviation of $\Delta\sigma(e^+ e^- \to Z \phi)$ from their SM values. We also examine Higgs boson decays $\phi\to b\bar{b}$ and $\phi\to \tau^+\tau^-$, which can have large electroweak (EW) contributions from triple Higgs couplings which are absent in the SM. It is found that for these benchmark scenarios, both EW and real emission corrections are sizeable and could be measured at a future $e^+ e^-$ colliders such as the ILC, CLIC, and CEPC., Comment: 28 pages, 15 figures, to appear in PRD

In the framework of the electroweak standard model, we investigated, in the center of mass frame, the Higgs boson production in the presence of an intense laser field via ${e}^{+} {e}^{-}$ annihilation $({e}^{+} {e}^{-}\rightarrow ZH)$. By comparing our results with those obtained by Djouadi \cite{1} for laser-free process, we show that the circularly polarized laser field affects significantly the $s$-channel Higgs boson production. We find that for a given number of exchanged photons, laser field strength and frequency, the total cross section decreases by several orders of magnitude. These effects of laser field on cross section are found to be consistent with what was found for muon pair production via QED process in the presence of a circularly polarized laser field \cite{2}., 17 pages, 11 figures

In this paper and within the standard Glashow-Weinberg-Salam model of electroweak interactions, we study theoretically the leptonic decay of the $W^{-}$-boson $(W^{-}\rightarrow \ell^{-}\bar{\nu}_{\ell})$ in the presence of a circularly polarized electromagnetic field and we examine the laser effect, in terms of its field strength and frequency, on the leptonic decay rate and the phenomenon of multiphoton processes. The calculations are carried out using the exact relativistic wave functions of charged particles in an electromagnetic field. It was found that the laser significantly contributed to reducing the probability of $W^{-}$-boson decay. We show that the laser-assisted decay rate is equal to the laser-free one only when the famous Kroll-Watson sum rule is fulfilled. The notable effect of the laser on the leptonic decay rate was reasonably interpreted by the well-known quantum Zeno effect or by the opening of channels other than leptonic ones to decay. We hope that this article paved the way for an upcoming paper to study the hadronic decay of the $W^{-}$-boson and then explore the laser effect on its lifetime and branching ratios., Comment: 19 pages, 13 figures

This paper revives the controversial debate that has arisen over the last two decades about the possibility that the electromagnetic field affects the lifetime or the decay rate of an unstable particle. In this research, we show, by performing analytical calculations and extracting numerical results, that the pion lifetime can be changed notably by inserting the decaying pion into an electromagnetic field only if the number of photons transferred between the decaying system and the laser field does not reach the well-known sum-rule. The influence of the laser parameters on the decay rate and branching ratio is also discussed. The surprising result obtained for the pion lifetime is referred to as the well-known quantum Zeno effect.

The production of a pair of charged Higgs bosons from $e^{+}e^{-}$ annihilation in the presence of a circularly polarized laser field is investigated in Inert Higgs doublet Model (IHDM) at ${e}^{+}{e}^{-}$ colliders. We have derived the analytical expression for the laser-assisted differential cross section by using the Dirac-Volkov formalism at leading order including the $Z$ and $\gamma$ diagrams. Since the laser-free cross section of this process depends, in the lowest order, only on the mass of the charged Higgs boson and the energy of the center of mass, we have analyzed the dependence of the total laser-assisted cross section on these parameters and also on the laser parameters such as the number of photons exchanged, the laser field intensity and its frequency. The results found indicate that the electromagnetic field decreases the order of magnitude of the total cross section as much as the laser field intensity increases or by decreasing its frequency. Moreover, it becomes high for low charged Higgs masses and low center of mass energies., Comment: 16 pages, 5 figures

We obtain Lie point symmetries for the system of partial differential equations describing flow and heat transfer in a thin liquid film on an unsteady stretching sheet and use them to construct invariants. We derive similarity transformations using deduced invariants that reduce the independent variables of the considered flow model. Such reductions lead to systems of ordinary differential equations. We solve these systems of ordinary differential equations analytically by applying the Homotopy analysis method.

In this paper, we have investigated the charged kaons decay at the lowest order in the presence of a circularly polarized laser field. To be more precise, we have examined the leptonic decay of both positive (matter) and negative (antimatter) kaon which weakly decay via the exchange of $W$ boson. Indeed, we have derived the expression of the leptonic decay width, the leptonic branching ratio, the leptonic ratio and the charged kaon lifetime by using the decay matrix approach. In addition, by using numerical computation, we have presented and discussed how the laser field influences these physical quantities. Moreover, we have analyzed the effect of the laser field on the parameter associated with the CPT symmetry. Then, we have concluded that, in the presence of an electromagnetic field and based on this CPT symmetry parameter, it is possible to control the dominance of matter over antimatter or vice-versa by applying an external field to either violate or conserve the CPT symmetry., Comment: 17 pages, 5 figures, 2 tables

Owing to recent advances in laser technology, it has become important to investigate fundamental laser-assisted processes in very powerful laser fields. In the present work and within the framework of laser-assisted quantum electrodynamics (QED), electron-proton scattering was considered in the presence of a strong electromagnetic field of circular polarization. First, we present a study of the process where we only take into account the relativistic dressing of the electron without the proton. Then, in order to explore the effect of the proton dressing, we fully consider the relativistic dressing of the electron and the proton together and describe them by using Dirac-Volkov functions. The analytical expression for the differential cross section (DCS) in both cases is derived at lowest-order of perturbation theory. As a result, the DCS is notably reduced by the laser field. It is found that the effect of proton dressing begins to appear at laser field strengths greater than or equal to $10^{10}~\text{V/cm}$ and it therefore must be taken into account. The influence of the laser field strength and frequency on the DCS is reported. A comparison with the Mott scattering and the laser-free results is also included., 22 pages, 9 figures

This paper addresses the problem radio mobile channel identification and equalization by blind algorithms. For this, we have proposed two algorithms, which are compared with: cumulants based algorithms, and adaptive filter algorithms (such us the constant modulus algorithm (CMA), Fractional Space CMA (FSCMA) and Sign Kurtosis Maximization Adaptive Algorithm (SKMAA)). However, The simulation results in noisy environment and for different SNR values with QPSK or 4QAM modulation shows that the proposed algorithms gives a good identification and equalization versus to the cumulants and the adaptive filter algorithms, for radio mobile channel.

A theoretical treatment, using the first Born approximation, is presented to analyse the results of relativistic laser-assisted proton – hydrogen atom scattering. Specific calculations are carried out for excitation of hydrogen atoms from 1s1/2 to 2s1/2 states by proton impact. We work in an approximation in which the incoming proton may be described by Dirac–Volkov states in the presence of a laser field. Semi-relativistic Darwin wave functions are used to describe the hydrogen atom in its initial and final states, while relativistic, spin, and laser interaction effects are also accounted for. The results presented in this paper show that the differential cross section for this process depends not only upon the energy of the incident proton, but also upon its interaction with the laser field through intensity and frequency.

Elastic scattering of hydrogen atoms by positron impact is studied at various values of incident positron energy and laser intensities. A discussion of differential cross-sections for positron scattering by hydrogen atoms in presence of laser field is presented along with anomalous magnetic moment of both electrons and positrons fully included. Differential cross sections for electrons and positrons remain almost equal in absence of anomalous magnetic moment effects. A comparison is also made with introduction of anomalous magnetic moment effects of both electrons and positrons. At intensities equal to 0.05 a.u. and above significant discrepancies in differential cross section is found even in first Born approximation.

Association of fatness with chronic metabolic diseases is a well-established fact, and a high prevalence of risk factors for these disorders has increasingly been reported in the third world. In order to incorporate any preventive strategies for such risk factors into clinical practice, decision-makers require objective evidence about the associated burden of disease. A cross-sectional study of 1321 adults from one of the districts of Balochistan, among the most economically challenged areas of Pakistan, was carried out for the measures of fatness and self-reported comorbidities. Body mass index (BMI), waist circumference (WC), and waist-to-hip ratio (WHR) were measured and demographic information and self-reported comorbidities were documented. The prevalence of obesity was 4.8% (95% CI: [3.8, 6.1]) and 21.7% (95% CI: [19.5, 24.0]), as defined by the World Health Organization (WHO) international and Asia/Asia-Pacific BMI cut-offs, respectively. The proportion exhibiting comorbidity increased with increasing levels of fatness in a dose-response relationship (p value < .001). An interaction of weight status with gender was observed to produce a significantly (p=.033) higher comorbidity among overweight women (odds ratio (OR) = 6.1 [1.2, 31.7]) compared with overweight men (OR = 1.1 [0.48, 2.75], p=.762).

In framework of first Born approximation, Salamin wave states have been used to calculate the differential cross section for laser assisted semirelativistic 1s–2s excitation of hydrogen atom by electron impact with anomalous magnetic moment effects fully included. The obtained results have been compared with laser assisted relativistic differential cross section without such effects. It is found that the electron’s anomalous magnetic moment effects in laser assisted 1s–2s excitation is very important particularly with increase of intensity. Good agreement with laser assisted differential cross section without anomalous magnetic moment effects is obtained when electron’s anomaly $$\kappa=4a_{e^-}=2(g-2)$$ is taken to be zero.

Alpha and beta activities per unit volume of air, due to radon, thoron and their decay products were measured in the outdoor atmosphere in Errachidia city, Morocco, by using both CR-39 and LR-115 type II solid-state nuclear track detectors (SSNTDs). Simultaneously, meteorological parameters such as air temperature, atmospheric pressure, and relative humidity were also measured in situ.. In addition, the outdoor radon activities show the highest value of the outdoor radon activity was determined in the early morning hours, and the lowest values were found in the afternoon, over a three month study period, between April-June 2006. The diurnal variations in the outdoor radon activity are found to exhibit correlation with relative humidity and negatively correlate with the air temperature. The annual effective dose in the present study for Errachidia environment is found to be 0.29 mSv/y.

In the framework of the first Born approximation and using the Dirac–Volkov formalism, we investigate the relativistic model describing the laser assisted elastic differential cross sections (DCSs) for positron scattering by the hydrogen atom. Both the DCSs for electron and positron are notably modified by the circularly polarized laser field, particularly in the regime of high energies and medium intensities. Comparing the two numerical DCSs, we recover the well-known result that the elastic scattering differential cross sections with and without laser field for a hydrogen atom by electron and positron impact are the same (Greiner and Reinhardt. Quantum Electrodynamics, 2nd ed., Springer Verlag, New York, Berlin, Heidelberg. 1994). The numerical results reveal that the differential cross section for positron – hydrogen atom scattering is significantly reduced with the increase of the electric field strength.

Laser assisted Coulomb scattering by relativistic electron and heavy electron (muon) is studied by using Salamin waves (Salamin 1993) in the Weak Field Approximation (WFA). Both electron and muon are described by the Dirac equation, with the anomalous magnetic moment effects fully included. The generalization of this paper to heavy electron (muon) gives interesting insights as to how the mass affects the magnitude of the differential cross sections. No significant difference in the muon's DCS with and without AMM effects was detected., Comment: I want to change the text

The paper presents results of radon (222Rn) and thoron (220Rn) levels in different parts of some selected plants used in Moroccan cooking and traditional medicine. Plant uptake of radionuclide is one of many vectors for introduction of contaminants into the human food chain. Thus, it is critical to understand the soil–plant relationships that control nuclide bioavailability. The radon and thoron concentrations have been determined in the studied samples and their corresponding soils, and that using the technique based on two types of solid state nuclear track detectors (SSNTDs) LR-115 type-II and CR-39. Transfer factors (TF) of 222Rn and 220Rn from soil to parts of various studied plants have been determined. TF for roots were higher than those for stems and leaves. The radon and thoron activities in the soils have been found varying from 0.87 0.06Bq.kg-1 to 6.20 0.47Bq.kg-1 and from 30 2.30mBq.kg-1 to 195±16mBq.kg-1, respectively. These values are lower in the leaves and stems than those determined in the roots of the studied plants. The aim of this study was to analyze the radon transfer from soil to different compartments of these plants and then to evaluate the radiotoxicity caused by radon in order to contribute to the health risk assessment.

The uptake of 238U and 232Th in different parts of some selected plants used in traditional treatment of hypertension and diabetes in south-eastern Morocco (Errachidia area) has been studied using two different types of solid state nuclear track detectors (SSNTDs) LR-115 type II and CR-39. Plant uptake of radionuclides is one of many vectors for introduction of contaminants into the human food chain. Thus, it is critical to understand soil–plant relationships that control nuclide bioavailability. Soil concentrations of uranium ranged from 6.10 to 11.62 ppm, with a mean of 7.90 ppm. Soil concentrations of thorium ranged from 2.70 to 4.80 ppm, with a mean of 3.41 ppm. Mean uranium specific activities were 8.38 Bq kg−1 in root tissue, 5 Bq kg−1 in stem tissue and 6.02 Bq kg−1 in leaf tissue. Mean thorium specific activities were 2.53 Bq kg−1 in root tissue, 1.64 Bq kg−1 in stem tissue and 1.96 Bq kg−1 in leaf tissue. The transfer factors of 238U and 232Th from soil to different parts (root, stem, leaf, seed and fruit) of studied plant samples have been investigated. The transfer factors obtained for root plants were markedly higher than those for leaf, stem, fruit and seed plants. Soil-to-plant transfer factor (TF) is one of the most important parameters to be used in transfer models for predicting the concentration of radionuclides in agricultural crops and for estimating dose impacts to man. This study of uranium and thorium uptake in plants used in traditional medicine is also significant as far as the health hazard effects of uranium and thorium in human being are concerned.

In this work, we review and correct the first Born differential cross section for the process of Mott scattering of a Dirac–Volkov electron, namely, expression (26) derived by Szymanowski et al. (Phys. Rev. A, 56, 3846 (1997)). In particular, we disagree with the expression of (dσ/dΩ) that they obtained and we give the exact coefficients multiplying the various Bessel functions appearing in the scattering differential cross section. Comparison of our numerical calculations with those of Szymanowski et al. shows qualitative and quantitative differences when the incoming total electron energy and the electric-field strength are increased particularly in the direction of the laser propagation. Such corrections are very important since the relativistic electronic dressing of any Dirac–Volkov charged particle gives rise to these coefficients that multiply the various Bessel functions, and the relativistic study of other processes (such as excitation, ionization, etc….) depends strongly upon the correctness and reliability of the calculations for this process of Mott scattering in the presence of a laser field. Our work has been accepted, Attaourti and Manaut (Phys. Rev. A, 68, 067401 (2003)) but only as a comment. In this paper, we give full details of the calculations as well as a clear explanation of the large discrepancies that their results could cause when working in the ultra relativistic regime and using a very strong laser field corresponding to an electric field strength ε = 5.89 au.