Washing-out final-state strong interactions in the longitudinal polarization asymmetry for e+e−→hadron near the Z0 peak to lowest e.m. order

1986 ◽  
Vol 94 (1) ◽  
pp. 15-24 ◽  
Author(s):  
B. W. Lynn ◽  
C. Verzegnassi
Keyword(s):  
Strong Interactions ◽  
Longitudinal Polarization ◽  
Polarization Asymmetry ◽  
Final State

scholarly journals QCD and QED corrections to the longitudinal polarization asymmetry

1990 ◽  
Vol 45 (3) ◽  
pp. 528-528 ◽  
Author(s):  
S. Jadach ◽  
J. H. K�hn ◽  
R. G. Stuart ◽  
Z. Was
Keyword(s):  
Longitudinal Polarization ◽  
Polarization Asymmetry

POSSIBLE DEVIATIONS IN Z0 PAIR PRODUCTION AT e+e− COLLIDERS DUE TO EXOTIC LEPTON MIXINGS

1990 ◽  
Vol 05 (08) ◽  
pp. 605-612
Author(s):  
A.K. NAGAWAT ◽  
SARDAR SINGH ◽  
N.K. SHARMA
Keyword(s):  
Standard Model ◽  
Differential Cross Section ◽  
Pair Production ◽  
Cross Section ◽  
Differential Cross ◽  
Linear Collider ◽  
Longitudinal Polarization ◽  
Polarization Asymmetry ◽  
Distinctive Features ◽  
Model Predictions

The deviations from standard model predictions for the pair production of Z0 at e+e− colliders with the inclusion of mixing between ordinary and exotic leptons are evaluated for (i) the differential cross section and (ii) the longitudinal polarization asymmetry at LEP II [Formula: see text] and at possible the next linear collider [Formula: see text] energies. For heavy exotic leptons (mE ~ 250 GeV) the deviations have distinctive features that could allow the possibility of distinguishing between mirror, vector-doublet and vector-singlet type of exotic lepton mixings.

scholarly journals Electroweak one-loop corrections to the process of fermion pair production in electron-positron annihilation

2019 ◽  
pp. 31-40
Author(s):  
Uladzimir U. Khasianevich ◽  
Tatiana V. Shishkina
Keyword(s):  
Radiation Energy ◽  
Phase Region ◽  
Polarization Asymmetry ◽  
Final State ◽  
Electron Positron Annihilation ◽  
Electron Positron ◽  
Unpolarized Case ◽  
Loop Approximation ◽  
The One ◽  
Threshold Energies

Numerical results for the total cross section, polarization asymmetry, as well as forward-backward asymmetry are presented. Calculations were carried out for longitudinal polarization of the initial electron-positron beams, as well as for the unpolarized case in the one-loop approximation for the standard electroweak Glashow – Weinberg – Salam model without considering quark fields. As a renormalization scheme, we used a non-minimal on-shell scheme with simultaneous renorma lization of the fields. In addition to considering the radiation of soft photons, numerical analysis of hard bremsstrahlung was performed. Analysis of the effect of the cut-off parameters of the phase region of the three-particle final state was made, which are the acollinearity angle between the final leptons, the detecting threshold energies of the final particles, and the radiation energy of the soft photons. An algorithm for obtaining ultraviolet convergent expressions is described. The calculations were carried out in the formalism of the Passarino – Veltman functions in the light-lepton approximation.

Parity conservation in strong interactions

1958 ◽  
Vol 246 (1247) ◽  
pp. 481-482
Keyword(s):  
Cross Section ◽  
Selection Rule ◽  
Radiative Capture ◽  
Weak Interactions ◽  
Relative Strength ◽  
Strong Interactions ◽  
Longitudinal Polarization ◽  
Heavy Particles ◽  
Parity Conservation ◽  
Γ Rays

The recent discovery that parity is not conserved in certain weak interactions has opened the question of the degree to which it is conserved in the strong interactions (internucleonic and electromagnetic). Parity non-conservation in such interactions may be detected by: (i) The violation of a selection rule which is absolute if parity is conserved. (ii) The presence of circular polarization of γ-rays or longitudinal polarization of heavy particles in reactions involving unpolarized initial systems and where the apparatus itself defines no screw sense. (iii) The presence of odd powers of cos θ in the angular distribution of radiations coming from well-defined nuclear states. Two experiments have been performed in class (i). The radiative capture 4 He(d, γ) 6 Li through the 0 + state at 3·57 MeV has been sought and its absence corresponds to F 2 < 1 X 10 -7 ( F is the relative strength of the parity non-conserving interaction). The reaction 7 Be( n , α)α with thermal neutrons has been sought and the limit on the cross-section corresponds to F 2 < 1 X 10 -7 .

QCD and QED corrections to the longitudinal polarization asymmetry

1988 ◽  
Vol 38 (4) ◽  
pp. 609-617 ◽  
Author(s):  
S. Jadach ◽  
J. H. Kühn ◽  
R. G. Stuart ◽  
Z. Was
Keyword(s):  
Longitudinal Polarization ◽  
Polarization Asymmetry

200kv superconducting cryo electron microscope

1987 ◽  
Vol 45 ◽  
pp. 642-643
Author(s):  
M. Iwatsuki ◽  
Y. Kokubo ◽  
Y. Harada ◽  
J. Lehman
Keyword(s):  
Electron Microscope ◽  
Structure Analysis ◽  
Organic Materials ◽  
Strong Interactions ◽  
Specimen Preparation ◽  
Great Effort ◽  
Electron Microscopic ◽  
Crystal Fields ◽  
Special Skill ◽  
Long Time

In recent years, the electron microscope has been significantly improved in resolution and we can obtain routinely atomic-level high resolution images without any special skill. With this improvement, the structure analysis of organic materials has become one of the interesting targets in the biological and polymer crystal fields.Up to now, X-ray structure analysis has been mainly used for such materials. With this method, however, great effort and a long time are required for specimen preparation because of the need for larger crystals. This method can analyze average crystal structure but is insufficient for interpreting it on the atomic or molecular level. The electron microscopic method for organic materials has not only the advantage of specimen preparation but also the capability of providing various information from extremely small specimen regions, using strong interactions between electrons and the substance. On the other hand, however, this strong interaction has a big disadvantage in high radiation damage.

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