scholarly journals SECOND-ORDER CONTRIBUTIONS TO ELASTIC LARGE-ANGLE BHABHA SCATTERING

1998 ◽  
Vol 13 (28) ◽  
pp. 2305-2316 ◽  
Author(s):  
A. B. ARBUZOV ◽  
E. A. KURAEV ◽  
B. G. SHAIKHATDENOV
Keyword(s):  
Cross Section ◽  
Photon Emission ◽  
Large Angle ◽  
Second Order ◽  
Feynman Diagrams ◽  
Soft Photon ◽  
Positron Scattering ◽  
High Energies ◽  
Bhabha Scattering ◽  
Electron Positron

The cross-section of (quasi-)elastic large-angle electron–positron scattering at high energies is calculated. Radiative corrections of the orders [Formula: see text] and [Formula: see text], except pure two-loop box contributions, are explicitly calculated. In the second order we considered the following sources of corrections: (a) virtual photonic corrections coming from squares of one-loop level amplitudes and their relevant interferences (vertex-type and box-type Feynman diagrams); (b) double soft photon emission and one-loop corrections to single soft photon emission. The results are presented analytically.

scholarly journals Second order contributions to elastic large-angle Bhabha scattering

2001 ◽  
Vol 516 (1-2) ◽  
pp. 33-38 ◽  
Author(s):  
E.W.N. Glover ◽  
J.B. Tausk ◽  
J.J. van der Bij
Keyword(s):  
Large Angle ◽  
Second Order ◽  
Bhabha Scattering

Resonant annihilation and production of high-energy electron-positron pairs in an external electromagnetic field

2020 ◽  
Vol 35 (03) ◽  
pp. 2040023 ◽  
Author(s):  
D. V. Doroshenko ◽  
V. V. Dubov ◽  
S. P. Roshchupkin
Keyword(s):  
Electromagnetic Field ◽  
Cross Section ◽  
Threshold Energy ◽  
External Electromagnetic Field ◽  
High Energy ◽  
Energy Electron ◽  
High Energy Electron ◽  
Annihilation Channel ◽  
Positron Scattering ◽  
Electron Positron

A resonant process of annihilation and production of high-energy electron-positron pairs in an external electromagnetic field is studied theoretically. This process is the annihilation channel of an electron-positron scattering. It is shown that the resonance in an external electromagnetic field is possible only when the certain combination of electron and positron initial energies is more than threshold energy. Also, the angle between initial electron and initial positron momenta directions must be small and satisfy the resonant conditions. This angle is determined by the high-energy of the initial pair and the threshold energy. An emerging electron-positron pair also flies out in a narrow cone along the direction of the initial pair and must be ultrarelativistic. For each fixed angle, energies of the final electron and positron can take from one to two values. It is shown that the resonant differential cross section can significantly exceed the corresponding Bhabha cross section without an external field.

MEASUREMENT OF THE HADRONIC CROSS SECTION AT KLOE/KLOE-2

2014 ◽  
Vol 35 ◽  
pp. 1460389
Author(s):  
ANTHONY PALLADINO ◽  
Keyword(s):  
Cross Section ◽  
Collision Energy ◽  
Large Angle ◽  
Pion Form Factor ◽  
Initial State ◽  
Hadronic Cross Section ◽  
Bhabha Scattering ◽  
State Radiation ◽  
The Standard Model ◽  
Using Data

The KLOE experiment at the DAΦNE ϕ-factory in Frascati was the first to use Initial State Radiation to precisely determine the e+e− → π+π−(γ) cross section below 1 GeV. This measurement is particularly important to test the Standard Model calculation for the anomalous magnetic moment of the muon, (g-2), where a long standing 3σ discrepancy between measurement and theory is observed. In 2005 and 2008 KLOE published two measurements of the π+π− cross section with the photon emitted at small angle. In 2011 an independent measurement of the π+π− cross section with the photon emitted at large angle was published using data at a collision energy of 1 GeV, 20 MeV below the ϕ-peak. A new analysis, published in 2013, derives the pion form factor directly from the bin-by-bin π+π−γ/μ+μ−γ ratio significantly reducing the systematic uncertainty, while the previous measurements were normalized to the DAΦNE luminosity using large angle Bhabha scattering. We present the final result of this measurement, as well as a preliminary value for the combined result of all KLOE hadronic cross section measurements, and evaluate the hadronic contribution to the muon anomaly.

First and Second Order Elastoplastic Analyses of Thin-Walled Metal Members using Generalized Beam Theory

2018 ◽  
Author(s):  
Miguel Abambres
Keyword(s):  
Finite Element ◽  
Stainless Steel ◽  
Cross Section ◽  
Beam Theory ◽  
Second Order ◽  
Flow Rule ◽  
Non Linear ◽  
Thin Walled ◽  
Shell Finite Element ◽  
Generalized Beam Theory

Original Generalized Beam Theory (GBT) formulations for elastoplastic first and second order (postbuckling) analyses of thin-walled members are proposed, based on the J2 theory with associated flow rule, and valid for (i) arbitrary residual stress and geometric imperfection distributions, (ii) non-linear isotropic materials (e.g., carbon/stainless steel), and (iii) arbitrary deformation patterns (e.g., global, local, distortional, shear). The cross-section analysis is based on the formulation by Silva (2013), but adopts five types of nodal degrees of freedom (d.o.f.) – one of them (warping rotation) is an innovation of present work and allows the use of cubic polynomials (instead of linear functions) to approximate the warping profiles in each sub-plate. The formulations are validated by presenting various illustrative examples involving beams and columns characterized by several cross-section types (open, closed, (un) branched), materials (bi-linear or non-linear – e.g., stainless steel) and boundary conditions. The GBT results (equilibrium paths, stress/displacement distributions and collapse mechanisms) are validated by comparison with those obtained from shell finite element analyses. It is observed that the results are globally very similar with only 9% and 21% (1st and 2nd order) of the d.o.f. numbers required by the shell finite element models. Moreover, the GBT unique modal nature is highlighted by means of modal participation diagrams and amplitude functions, as well as analyses based on different deformation mode sets, providing an in-depth insight on the member behavioural mechanics in both elastic and inelastic regimes.

scholarly journals Spin-one dark matter and gamma ray signals from the galactic center

2020 ◽  
Vol 2020 (8) ◽  
Author(s):  
H. Hernández-Arellano ◽  
M. Napsuciale ◽  
S. Rodríguez
Keyword(s):  
Dark Matter ◽  
Cross Section ◽  
Gamma Ray ◽  
Galactic Center ◽  
Photon Emission ◽  
Scalar Coupling ◽  
Initial State ◽  
Internal Bremsstrahlung ◽  
Resonance Effects ◽  
State Radiation

Abstract In this work we study the possibility that the gamma ray excess (GRE) at the Milky Way galactic center come from the annihilation of dark matter with a (1, 0) ⊕ (0, 1) space-time structure (spin-one dark matter, SODM). We calculate the production of prompt photons from initial state radiation, internal bremsstrahlung, final state radiation including the emission from the decay products of the μ, τ or hadronization of quarks. Next we study the delayed photon emission from the inverse Compton scattering (ICS) of electrons (produced directly or in the prompt decay of μ, τ leptons or in the hadronization of quarks produced in the annihilation of SODM) with the cosmic microwave background or starlight. All these mechanisms yield significant contributions only for Higgs resonant exchange, i.e. for M ≈ MH /2, and the results depend on the Higgs scalar coupling to SODM, gs. The dominant mechanism at the GRE bump is the prompt photon production in the hadronization of b quarks produced in $$ \overline{D}D\to \overline{b}b $$ D ¯ D → b ¯ b , whereas the delayed photon emission from the ICS of electrons coming from the hadronization of b quarks produced in the same reaction dominates at low energies (ω < 0.3 GeV ) and prompt photons from c and τ , as well as from internal bremsstrahlung, yield competitive contributions at the end point of the spectrum (ω ≥ 30 GeV ). Taking into account all these contributions, our results for photons produced in the annihilation of SODM are in good agreement with the GRE data for gs ∈ [0.98, 1.01] × 10−3 and M ∈ [62.470, 62.505] GeV . We study the consistency of the corresponding results for the dark matter relic density, the spin-independent dark matter-nucleon cross-section σp and the cross section for the annihilation of dark matter into $$ \overline{b}b $$ b ¯ b , τ+τ−, μ+μ− and γγ, taking into account the Higgs resonance effects, finding consistent results in all cases.

scholarly journals Large Angle Elastic Scattering at High Energies

1966 ◽  
Vol 35 (4) ◽  
pp. 748-750
Author(s):  
Tetsuro Kitazoe ◽  
Hiroshi Nakatani
Keyword(s):  
Elastic Scattering ◽  
Large Angle ◽  
High Energies

Optimal Solutions for Nonhomogeneous Multiply-Connected Torsional Sections

1989 ◽  
Vol 111 (1) ◽  
pp. 87-93 ◽  
Author(s):  
A. Mioduchowski ◽  
M. G. Faulkner ◽  
B. Kim
Keyword(s):  
Numerical Simulation ◽  
Boundary Value Problem ◽  
Cross Section ◽  
Boundary Value ◽  
Optimization Procedure ◽  
Second Order ◽  
External Boundary ◽  
Optimal Solutions ◽  
Torsion Problem ◽  
Multiply Connected

Optimization of a second-order multiply-connected inhomogeneous boundary-value problem was considered in terms of elastic torsion. External boundary and material proportions are the applied constraints in finding optimal internal configurations of the cross section. The optimization procedure is based on the numerical simulation of the membrane analogy and the results obtained indicate that the procedure is usable as an engineering tool. Optimal solutions are obtained for some representative cases of the torsion problem and they are presented in the form of tables and figures.

Rescattering model of K±p elastic large-angle collisions at high energies

1973 ◽  
Vol 7 (17) ◽  
pp. 879-884
Author(s):  
N. Masuda ◽  
S. Mikamo
Keyword(s):  
Large Angle ◽  
High Energies
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