منابع مشابه
The finite mass calculations for γγ → l + l − γ process
The luminosity of photon beams at the future γγ-colliders [1, 2] will be measured using the well-known QED reactions of light lepton pairs creation (γγ → ll [3], γγ → 4l [4] and others [1, 5]). It turned out, that in the experiments using beams of similar helicity (total helicity of γγ-system J = 0) the most of these processes are greatly suppressed and can’t be used. However these experiments ...
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We propose a new method that fixes the coupling to two photons of the recently found lightest QCD resonance, the σ. This coupling provides crucial information for discriminating the yet unknown nature of this special state. Our method uses available data on the nucleon polarizabilities together with analyticity and unitarity. Taking into account all the uncertainties, our result is Γpole = 1.2±...
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We study the helicity amplitudes of the process γγ → ZZ in the Standard Model at high energy. These amplitudes receive contributions from the W and charged quark and lepton loops, analogous to those encountered in the γγ → γγ, γZ cases studied before. But γγ → ZZ also receives contributions from the Higgs s-channel poles involving the effective Higgs-γγ vertex. At energies & 300GeV , the amplit...
متن کاملBeamstrahlung Induced Minijet Backgrounds at Future Colliders and a Model for Σ Inel Γγ A
The phenomenon of beamstrahlung can give rise to potentially dangerous hadronic backgrounds due to minjet production at the future linear colliders as well as at the γγ colliders that are under consideration. In this talk I will review briefly the current estimates of these backgrounds and predictions of the eikonalised minijet model for σ inel γγ. I end by pointing out issues that need to be s...
متن کاملThe σ → γγ Width from the Nucleon Electromagnetic Polarizabilities
The lightest QCD resonance, the σ, has been recently fixed in the ππ scattering amplitude. The nature of this state remains nowadays one of the most intriguing and difficult issues in particle physics. Its coupling to photons is crucial for discriminating its structure. We propose a new method that fixes this coupling using only available precise experimental data on the proton electromagnetic ...
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ژورنال
عنوان ژورنال: Physics of Atomic Nuclei
سال: 2003
ISSN: 1063-7788,1562-692X
DOI: 10.1134/1.1634321