First measurement of helicity-dependent cross sections in π0η photoproduction from quasi-free nucleons

First measurement of helicity-dependent cross sections in π0η photoproduction from quasi-free nucleons

Dades bibliogràfiques
Parent link:Physics Letters B
Vol. 786.— 2018.— [P. 305-312]
Autor corporatiu: Национальный исследовательский Томский политехнический университет Исследовательская школа физики высокоэнергетических процессов
Altres autors: Kaser A., Dieterle M., Witthauer L., Fiks (Fix) A. I. Alexander Ivanovich
Sumari:Title screen
The helicity-dependent cross sections for the photoproduction of pairs have been measured for the first time. The experiment was performed at the tagged photon facility of the Mainz MAMI accelerator with the combined Crystal Ball – TAPS calorimeter. The experiment used a polarized deuterated butanol target and a circularly polarized photon beam. This arrangement allowed the (photon and target spin antiparallel) and (parallel spins) components to be measured for quasi-free production of pairs off protons and neutrons. The main finding is that the two helicity components contribute identically, within uncertainties, for both participant protons and neutrons. The absolute couplings for protons and neutrons are also identical. This means that nucleon resonances contributing to this reaction in the investigated energy range have almost equal electromagnetic helicity couplings, and . Identical couplings for protons and neutrons are typical for resonances and identical and components are only possible for states, which constrains possible contributions of nucleon resonances.
Idioma:anglès
Publicat: 2018
Matèries:
электронный ресурс
труды учёных ТПУ
фотоны
протоны
нейтроны
Accés en línia:https://doi.org/10.1016/j.physletb.2018.10.006
Format: Electrònic Capítol de llibre
KOHA link:https://koha.lib.tpu.ru/cgi-bin/koha/opac-detail.pl?biblionumber=660082

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