Born Results Research Articles

Nonperturbative theory for the QED corrections to elastic electron-nucleus scattering

A potential for the vertex and self-energy correction is derived from the first-order Born theory. The inclusion of this potential in the Dirac equation, together with the Uehling potential for vacuum polarization, allows for a nonperturbative treatment of these quantum electrodynamical effects within the phase-shift analysis. Investigating the 12C and 208Pb targets, a considerable deviation of the respective cross section change from the Born results is found for the heavier target. It is shown that at low impact energies the dispersion effects play no role. Estimates for the correction to the beam-normal spin asymmetry and its accuracy at 5 MeV (for 208Pb and 197Au) are also provided.

Electron impact single ionization TDCS of H2O at 81 eV for coplanar asymmetric emission of electrons

We report the results of triple differential cross section (TDCS) for the electron impact single ionization of water molecules at incident electron energy 81 eV for coplanar asymmetric emission of electrons. The TDCS results have been obtained in distorted wave second Born approximation using orientation averaged molecular orbital (OAMO) approximation. The TDCS results have been calculated for the ionization of 1b1 and 3a1 molecular orbital of water molecules for the coplanar asymmetric emission of electrons. The obtained theoretical TDCSs are compared with the available measurements as well as with the first Born results. The second Born results are found to be significant by improving agreement with the measurements particularly in the binary peak region.

Double Differential Cross-sections for Ionization of Metastable 2P-state Hydrogen Atoms by Electrons at Intermediate Energies with Exchange Effects

Double differential cross sections were obtained from the triple differential cross sections. The present calculations are compared with the hydrogenic ground-state experimental data, theoretical results, and DDCS first Born results. Discrepancies have been found between the present results and those measurements and theoretical results and also qualitative agreement with those of compared theories. The exchange effect results give an enormous prospect for experimental outcomes in the field of ionization problems. We are expecting that the present study makes more significant contribution to the study of atomic scattering problems using the multiple scattering theories. In the future calculations, other kinematic conditions or other atomic species will also be interesting and significant.

Clinical and Laboratory Results of Newborn Babies Born from Pregnant Women Infected with COVID-19

Amaç: Dünya çapında bir pandemiye neden olan COVID-19 virüsü çok sayıda can kaybına neden olmuştur. Yeni tip koronavirüs ile enfekte olan gebelerin yenidoğan bebekleri ile ilgili çalışmalar yapılmakta olup vertikal geçiş açısından çalışmalar devam etmektedir. Biz de çalışmamızda COVID-19 ile enfekte olan gebelerden doğan yenidoğan bebeklerin klinik ve laboratuvar sonuçlarını değerlendirmeyi planladık. 
 Gereçler ve Yöntem: Bu retrospektif çalışma, Sağlık Bilimleri Üniversitesi Konya Eğitim ve Araştırma Hastanesi Yenidoğan Yoğun Bakım Ünitesinde Nisan 2020- Ağustos 2020 tarihleri arasında yapıldı. Doğum yaptığı esnada revers transkriptaz-polimeraz zincir reaksiyonu (RT-PCR) ile yeni tip koronavirüs (SARS-CoV-2) enfeksiyonu saptanan gebelerden doğan yenidoğan bebeklerin çalışmaya dahil edilmesi planlandı. Gebelerin SARS-CoV-2 ile enfekte olduğu dönemde bakılan tam kan sayımı, biyokimyasal değerleri, akut faz reaktanları, D-Dimer ve ferritin değerleri kaydedildi. Yenidoğan bebeklerde ise tam kan sayımı, biyokimyasal değerleri ve akut faz reaktanları değerlendirilmeye alındı. Yenidoğan bebeklerin hepsinde 24 saat ile bakılan 2 tane COVID RT-PCR sonuçları not edildi. Gereken verilerine ulaşılan 14 gebe ve yenidoğan bebeği çalışmaya dahil edildi. 
 Bulgular: Yenidoğan bebeklerin hepsinde 24 saat ara ile bakılan 2 tane COVID RT-PCR sonucu negatif olarak geldi. Yenidoğanların lenfosit yüzdesi ve değeri annelerine göre istatistiksel olarak yüksek saptandı (p

Newborn Hearing Screening Results of Infants Born To Mothers Who Had COVID-19 Disease During Pregnancy: A Retrospective Cohort Study

Objective:Viral infections are known to be a risk factor for neonatal hearing loss. COVID-19 infection has been reported to affect hearing test results in one small sample sized study. We aimed to investigate the incidence the risk of neonatal hearing loss in infants of mothers who had COVID-19 infection during pregnancy, regarding their trimesters, by evaluating the neonatal hearing screening results.Design:In this retrospective case-control study, neonatal hearing test results of 458 women with a history of COVID-19 infection in pregnancy were compared with 339 women who gave birth before the pandemic. Data of pregnant women who attended the COVID-19 outpatient clinic of the emergency service of a tertiary pandemic hospital and who had confirmed infection with a reverse transcriptase–polymerase chain reaction (RT-PCR) test were determined from the hospital’s records and their neonatal hearing screening results were analyzed from the national database. Neonates born before <34 weeks, and with reported risk factors in the database such as congenital anomaly or known TORCH infection during pregnancy were excluded. The screening tests, Automated Auditory Brainstem Response or Transient Evoked Otoacoustic Emission (TEOAE), were used for screening, and patients who failed the first screening were reevaluated at least 2 weeks apart with a second screening.Results:The incidence of failed second screening was 1.3% in the COVID-19 group and 2.9% in controls, and no significant difference was observed between the two groups according to the final screening results on the second test. Among the 458 mothers, 8 were infected in first trimester, 126 in second trimester, 127 in third trimester but did not deliver within 15 days after infection and 197 were positive at birth. Six neonates in the infected group failed the second screening (3 [2.4%] in the second trimester, 1 [0.8%] third trimester, and 2 [1.0%] positive at birth).Conclusions:COVID-19 infection during pregnancy was not found to be a risk factor for hearing loss, according to the newborn hearing screening results.

Triple differential cross-sections for the ionization of metastable 2P-state hydrogen atoms by electrons with exchange effects

In this paper, triple differential cross-sections for the ionization of metastable 2P-state hydrogen atoms by 250 eV electron energy with exchange effects for various kinematic conditions are calculated. Multiple scattering theory proposed by Das and Seal in Phys. Rev. A 47, 2978 (1993) is utilized here. The computational results provide significant peak features that show good qualitative agreement with the hydrogenic ground-state experimental data and theoretical results and the present first Born results. In addition, physical origin of the peaks of the cross-section curves is investigated.

High-energy electroproduction in an atomic field

The differential cross section of high-energy electroproduction in the electric field of heavy atoms is derived. The result is obtained with the exact account of the atomic field by means of the quasiclassical approximation to the wave functions in the external field. The Coulomb corrections substantially modify the differential cross section compared with the Born result. They lead to the azimuth asymmetry in the differential cross section for the polarized incoming electron. The Coulomb corrections to the total cross section are obtained in the leading logarithmic approximation.

High-energye+e−photoproduction in the field of a heavy atom accompanied by bremsstrahlung

Helicity amplitudes and differential cross section of high-energy $e^+e^-$ photoproduction accompanied by bremsstrahlung in the electric field of a heavy atom are derived. The results are exact in the nuclear charge number and obtained in the leading quasiclassical approximation. They correspond to the leading high-energy small-angle asymptotics of the amplitude. It is shown that, in general, the Coulomb corrections essentially modify the differential cross section as compared to the Born result. When the initial photon is circularly polarized the Coulomb corrections lead to the asymmetry in the distribution over the azimuth angles $\varphi_i$ of produced particles with respect to the replacement $\varphi_i\to -\varphi_i$.

Electron impact ionization of metastable 2P-state hydrogen atoms in the coplanar geometry

Triple differential cross sections (TDCS) for the ionization of metastable 2P-state hydrogen atoms by electrons are calculated for various kinematic conditions in the asymmetric coplanar geometry. In this calculation, the final state is described by a multiple-scattering theory for ionization of hydrogen atoms by electrons. Results show qualitative agreement with the available experimental data and those of other theoretical computational results for ionization of hydrogen atoms from ground state, and our first Born results. There is no available other theoretical results and experimental data for ionization of hydrogen atoms from the 2P state. The present study offers a wide scope for the experimental study for ionization of hydrogen atoms from the metastable 2P state.

Photon-pair jet production via gluon fusion at the LHC

Photon-pair direct or jet-associated production is important for relevant standard model measurement, Higgs and new physics searches at the Large Hadron Collider (LHC). The loop-induced gluon-fusion process gg → γγg, which formally contributes only at the next-to-next-to-leading order to γγj productions, may get enhanced by the large gluon flux at the LHC. We have checked and confirmed previous results on gg → γγ (Dicus and Willenbrock 1988 Phys. Rev. D 37 1801), γγg (de Florian and Kunszt 1999 Phys. Lett. B 460 184) at one loop, using the traditional Feynman diagram based approach, taking into account the quark mass effects, and updated them further for the 7 and 14 TeV LHC with new inputs and settings. We provide the details and results of the calculations, which involve manipulation of rank-5 pentagon integrals. Our results show that the gluon-fusion process can contribute about 10% of the Born result, especially at small Mγγ and PTγγ, and increase further the overall scale uncertainty. Top quark loop effects are examined in detail, which become important near or above the threshold Mγγ ≳ 2mt.

Mathematical Modeling and Simulation Based on the Light Particles Doctrine

Gong Zutong academician guessed that the structure of the photon may be similar to the hydrogen atom which consists of a negative charge and a positive charge with the equal power, and the negative charge rotates around the positive charge in a spherical orbit. Based on this conjecture, to establish respectively the equation of photon movement for the dual-slit interference and single slit diffraction experiments. To get respectively the light intensity distribution model using complex integration method. Finally, to get that the width of the diffraction pattern of the conjecture is obviously wider than the results of Born through mathematical simulation in MATLAB software.

Ionization and excitation in collisions between antiprotons and H(1s) atoms studied with Sturmian bases

Coupled two-center as well as one-center Sturmian cross sections have been determined for ionization and excitation in $\mathrm{p\ifmmode \bar{}\else \={}\fi{}}$-H($1s$) collisions at $\mathrm{p\ifmmode \bar{}\else \={}\fi{}}$ energies from 1 to 16 000 keV, following the author's recent work for $p$-H($1s$) collisions [Phys. Rev. A 80, 032701 (2009)]. Basis convergence is studied in detail. Results for ionization and excitation are compared to other coupled-state results and to numerical results, as well as limited experimental results for ionization only. Except for the large, two-center coupled-Gaussian-pseudostate calculation of Toshima for ionization only [Phys. Rev. A 64, 024701 (2001)], previous calculations employed one-center bases, including a one-center Sturmian calculation by Igarashi et al. [Phys. Rev. A 61, 062712 (2000)]. A strong contrast with $p$-H collisions is confirmed at intermediate energies, while at high energies the extent of agreement is revealed between coupled-state results for the two collisional systems, as well as with first Born results.

Strong suppression of Coulomb corrections to the e + e − pair production cross section in ultrarelativistic nuclear collisions

The Coulomb corrections to the cross section of $e^+e^-$ pair production in ultrarelativistic nuclear collisions are calculated in the next-to-leading approximation with respect to the parameter $L=\ln \gamma_A\gamma_B$ ($\gamma_{A,B}$ are the Lorentz factors of colliding nuclei). We found considerable reduction of the Coulomb corrections even for large $\gamma_A\gamma_B$ due to the suppression of the production of $e^+e^-$ pair with the total energy of the order of a few electron masses in the rest frame of one of the nuclei. Our result explains why the deviation from the Born result were not observed in the experiment at SPS.

A simple formula for dielectric polarisation energies: The Sheffield Solvation Model

This work introduces the ‘Sheffield Solvation’ model for calculating the electrostatic component of molecular solvation energy. The resulting formula can be included in standard modelling technology with very low computational cost. The model replaces detailed information about local atomic environments (such as found in Generalised Born approaches), by using two global parameters. The methodology is validated against accurate Poisson–Boltzmann calculations, and compared to Generalised Born results.

Bone mass, density and body composition in preterm and full-term born children-preliminary results

Bone mass, density and body composition in preterm and full-term born children-preliminary results

Formula omitted] two-loop electroweak correction to Higgs-boson decay to bottom quarks

We analytically calculate the dominant two-loop electroweak correction, of O ( G F 2 m t 4 ) , to the partial width of the decay of a Higgs boson, with mass M H ≪ m t , into a bottom-quark pair, and describe the most important conceptual and technical details of our calculation. As a by-product of our analysis, we also recover the O ( α s G F m t 2 ) correction. Relative to the Born result, the O ( G F 2 m t 4 ) correction turns out to be approximately + 0.047 % and, thus, more than compensates the O ( α s G F m t 2 ) one, which amounts to approximately − 0.022 % .

Electron scattering off simple atoms for large momentum transfer collisions

In a previous paper this author examined the Born expansion and isolated those parts of the expansion that contribute most significantly to the scattering amplitude for large momentum transfer collisions in inelastic collisions from the ground state of both hydrogen and helium. It turned out that certain terms where the scattering electron interacts once with the nucleus and once with the other electron dominate. The physical reason is that large momentum transfer collisions require the nucleus to take the bulk of the incident momentum but require an interaction with the one of the bound electrons to change the state of the atom. The arguments are quite general and this paper will extend this analysis by comparing the inelastic results obtained by this method for hydrogen and helium to a close coupling calculation with many intermediate states. Further, we will extend this analysis to the correction to the 1st Born result for elastic electron–hydrogen and electron–helium collisions and provide some results for scattering from the initial metastable states of hydrogen for large momentum transfer collisions. A comparison of the results of this analytic approach will be made to the numerical close coupling approach and experiments where available. The agreement is remarkable.

EINSTEIN'S FLUCTUATION FORMULA: A HISTORICAL OVERVIEW

A historical overview is given on the basic results which appeared by the year 1926 concerning Einstein's fluctuation formula of black-body radiation, in the context of light-quanta and wave-particle duality. On the basis of the original publications – from Planck's derivation of the black-body spectrum and Einstein's introduction of the photons up to the results of Born, Heisenberg and Jordan on the quantization of a continuum – a comparative study is presented on the first lines of thoughts that led to the concept of quanta. The nature of the particle-like fluctuations and the wave-like fluctuations are analysed by using several approaches. With the help of classical probability theory, it is shown that the infinite divisibility of the Bose distribution leads to the new concept of classical "poissonian photo-multiplets" or to the "binary photo-multiplets" of fermionic character. As an application, Einstein's fluctuation formula is derived as a sum of fermion type fluctuations of the binary photo-multiplets.

Double ionization of helium by electron impact: angular distributions at low incident energy

A complete analysis of our recent (e, 3e) experiments on helium at 601 eV incident energy (Lahmam-Bennani et al 2003 Phys. Rev. A 67 010701) is conducted by using an approximate 6C model which accounts for the interaction between all four particles (the scattered electron, the two ejected electrons and the nucleus) in the final state. An accurate wavefunction for the initial state is also used. The agreement between experiments and theory is not always good even though most peaks and dips can be explained. Comparison is also made with the results of the first Born-BBK approximation as well as with approximate second Born results.

Competition between Intramolecular Hydrogen Bonds and Solvation in Phosphorylated Peptides: Simulations with Explicit and Implicit Solvent

The atomic-level mechanisms of protein regulation by post-translational phosphorylation remain poorly understood, except in a few well-studied systems. Molecular mechanics simulations can in principle be used to help understand and predict the effects of protein phosphorylation, but the accuracy of the results will of course depend on the quality of the force field parameters for the phosphorylated residues as well as the quality of the solvent model. The phosphorylated residues typically carry a -2 charge at physiological pH; however, the effects of phosphorylation can sometimes be mimicked by substituting Asp or Glu for the phosphorylated residue. Here we examine the suitability of explicit and implicit solvent models for simulating phospho-serine in both the -1 and -2 charge states. Specifically, we simulate a capped phosphorylated peptide, Ace-Gly-Ser-pSer-Ser-Nme, and compare the results to each other and to experimental observables from an NMR experiment. The first major conclusion is that explicit water models (TIP3P, TIP4P and SPC/E) and a Generalized Born implicit solvent model provide reasonable agreement with the experimental observables, given appropriate partial charges for the phosphate group. The Generalized Born results, however, show greater hydrogen bonding propensity than the explicit solvent results. Distance dependent dielectric treatments perform poorly. The second major conclusion is that many ensemble-averaged properties obtained for the phosphopeptide in the -1 and -2 charge states are strikingly similar; the -1 species has a slightly higher propensity to form internal hydrogen bonds. All of the results can be rationalized by quantifying the strength of the P-O/H-N hydrogen bond, which depends on a sensitive balance between strongly favorable charge/dipole and dipole/dipole interactions and strongly unfavorable desolvation.