Quark and antiquark polarization effects inqq¯andqq¯gfinal states in high energy collisions of polarized electrons and positrons

1997 ◽  
Vol 56 (1) ◽  
pp. 407-425 ◽  
Author(s):  
Haakon A. Olsen ◽  
John B. Stav
Keyword(s):  
High Energy ◽  
Polarized Electrons ◽  
Polarization Effects ◽  
Electrons And Positrons ◽  
High Energy Collisions

scholarly journals High Energy Polarized e+e− Beams

2016 ◽  
Vol 40 ◽  
pp. 1660089
Author(s):  
Yu. Shatunov ◽  
I. Koop ◽  
A. Otboev ◽  
S. Mane
Keyword(s):  
Time Constant ◽  
High Energy ◽  
Energy Calibration ◽  
Degree Of Polarization ◽  
Beam Polarization ◽  
Polarized Electrons ◽  
Electrons And Positrons ◽  
Spin Resonance ◽  
Very High ◽  
Buildup Time

Recently, the wide discussion about Higgs-factory design again returns to problem of high energy polarized electrons and positrons. It’s good known the radiative beam polarization at LEP-collider. It was obtained after spin resonance suppression at [Formula: see text] pick, but didn’t appear at energies above 70 GeV due to an enhancement of unavoidable depolarization effects. We examine in this paper various ideas for radiative polarization at TLEP/FCC-ee and formulate some estimates for the polarization buildup time and the asymptotic polarization. Using wigglers, a useful degree of polarization (for energy calibration), with a time constant of about 1 h, may be possible up to the threshold of W pair production. At higher energies such as the threshold of Higgs production, attaining a useful level of polarization may be difficult in a planar ring. With Siberian Snakes, wigglers and some imagination, polarization of reasonable magnitude, with a reasonable time constant (of not more than about 1 h), may be achievable at very high energies.

scholarly journals Properties of Elementary Particle Fluxes in Primary Cosmic Rays Measured with the Alpha Magnetic Spectrometer on the International Space Station

2019 ◽  
Vol 209 ◽  
pp. 01007
Author(s):  
Francesco Nozzoli
Keyword(s):  
Electron Flux ◽  
Space Station ◽  
Cosmic Ray ◽  
High Energy ◽  
Precision Measurements ◽  
High Energy Electrons ◽  
Electrons And Positrons ◽  
Positron Flux ◽  
Rigidity Dependence ◽  
Alpha Magnetic Spectrometer

Precision measurements by AMS of the fluxes of cosmic ray positrons, electrons, antiprotons, protons as well as their rations reveal several unexpected and intriguing features. The presented measurements extend the energy range of the previous observations with much increased precision. The new results show that the behavior of positron flux at around 300 GeV is consistent with a new source that produce equal amount of high energy electrons and positrons. In addition, in the absolute rigidity range 60–500 GV, the antiproton, proton, and positron fluxes are found to have nearly identical rigidity dependence and the electron flux exhibits different rigidity dependence.

scholarly journals Strangeness Suppression and Color Deconfinement

2018 ◽  
Vol 171 ◽  
pp. 02005
Author(s):  
Helmut Satz
Keyword(s):  
Initial Temperature ◽  
Strange Particle ◽  
High Energy ◽  
Universal Function ◽  
Ideal Gas ◽  
Entropy Density ◽  
Suppression Factor ◽  
Thermal Medium ◽  
High Energy Collisions ◽  
Hadronic Resonances

The relative multiplicities for hadron production in different high energy collisions are in general well described by an ideal gas of all hadronic resonances, except that under certain conditions, strange particle rates are systematically reduced. We show that the suppression factor γs, accounting for reduced strange particle rates in pp, pA and AA collisions at different collision energies, becomes a universal function when expressed in terms of the initial entropy density s0 or the initial temperature T of the produced thermal medium. It is found that γs increases from about 0.5 to 1.0 in a narrow temperature range around the quark-hadron transition temperature Tc ≃ 160 MeV. Strangeness suppression thus disappears with the onset of color deconfinement; subsequently, full equilibrium resonance gas behavior is attained.

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