F Gh

Differential cross-section measurements of elastic scattering of π± on4He are presented. The experiment was carried out with the high-pressure helium self-shunted streamer chamber surrounded by a hodoscope of scintillation counters. Measurements were fulfilled both for positive and negative pions at 68, 98, 135, 145 and 156 MeV, for negative pions also at 120, 174 and 208 MeV. The differential and total elastic-scattering cross-sections are compared with optical-model calculations using the Kisslinger and Laplacian potentials. Some results, obtained from an energy-dependent phase shift analysis, are also presented. Sono presentati i risultati della misura della sezione d’urto differenziale di diffusione elastica (π±,4He) a 68, 98, 135, 145, 156 MeV e (π−,4He) a 120, 174, 208 MeV. I dati sperimentali sono confrontati con le previsioni del modello ottico. È stata pure fatta un’analisi in fase dipendente dell’energia. Приводятся новые данные по дифференциальным сечениям упругого рассеяния эаряженных пионов на ядрах гелия-4, полученные в зкспериментах с гелиевой стримерной камерой высокого давления на синхроциклотроне ЛЯП ОИЯИ. Приводятся данные по фаэовому аналиэу, эависяшему от знергии, проводится сравнение с расчетами по оптической модели.