منابع مشابه
R Values in Low Energy e+e− Annihilation
whereQf is the fractional charge of the quark, and the factor of 3 in front counts the three colors for each flavor. The cross section of the pure QED process is σ(e+e− → μ+μ−) = 4πα2/3s. The value of R, which counts directly the number of quarks, both flavor and colors, is expected to be constant so long as the centerof-mass (cm) energy of the annihilated e+e− does not overlap with resonances ...
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The recent results of the CMD-2, SND, KLOE, and BABAR experiments on ee annihilation into hadrons at low energies are reviewed.
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We have a very limited knowledge about how the confinement mechanism works in processes like ee → qqg . . . g, when there are identical colour charges. In this case the partons can be connected by a string or a cluster chain in several different ways. We do not know if in such a situation Nature chooses a particular configuration at random, or if some configuration is dynamically favoured. Also...
متن کاملSuperstatistics in high energy physics: Application to cosmic ray energy spectra and ee annihilation
We work out a superstatistical description of high-energy scattering processes that takes into account temperature fluctuations in small volume elements. For Γ-distributed fluctuations of the inverse temperature one effectively obtains formulas similar to those used in nonextensive statistical mechanics, whereas for other temperature distributions more general superstatistical models arise. We ...
متن کاملp̄p low energy parameters from annihilation cross section data
Abstract. The recent experimental data obtained by the OBELIX group on total p̄p annihilation cross section are analysed; the low energy spin averaged parameters of the p̄p scattering amplitude (the imaginary parts of the S-wave scattering length and P-wave scattering volume) are extracted from the data. Their values are found to be equal to Imasc = −0.69±0.01(stat)±0.03(sys) fm, ImAsc = −0.76±0....
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ژورنال
عنوان ژورنال: International Journal of Modern Physics A
سال: 2000
ISSN: 0217-751X,1793-656X
DOI: 10.1142/s0217751x00001889