R. Carrara

Annihilation into pions of the\bar pn system from antiprotons at rest in deuterium

SummaryApproximately 20 000 pionic annihilations on neutrons of antiprotons brought to rest in a deuterium bubble chamber have been measured and analysed. 1, 3 and 5-prongs events were studied in detail and the rates into the various multipion final states were determined. Strong production of the pionic resonances ρ, ω and f0 has been observed, and their production rates are reported. A comparison of some two-body annihilations on protons (in hydrogen) and neutrons (in deuterium) has been accomplished finding agreement between the production rates. The ratio of the number of annihilations on the proton ans the neutron of the deuterium has been determined.RiassuntoSi sono misurate ed analizzate circa 20 000 annichilazionie «pioniche» su neutroni di antiprotoni portati a riposo in una camera a bolle a deuterio. Si sono studiate particolarmente le annichilazioni in uno, tre e cinque «rami» carichi e si sono determinate le frequenze dei vari stati pionici finali. Si è osservata una forte produzione della risonanze ρ, ω ed f0 e si danno dei valori per la loro frequenza di produzione. Confrontando alcuni tipi di annichilazioni a due corpi su protone (in idrogeno) con le corrispondenti su neutrone (in deuterio) si è trovato accordo fra le relative frequenze di produzione. Si è infine determinato il rapporto fra il numero di annichilazioni sul protone e quello sul neutrone del deuterio.РезюмеБыли проведены измерения и анализ приблизительно 20 000 случаев мезонной аннигияции остановившихся антнпротонов на нейтронах в дейтериевой пузырьковой камере. Подробно изучались одно-, трех-, и пятилучевые собятия, и были определены скорости распадов для различного числа мезонов в конечном состоянии. Было обнаружено сильное рождение мезонных резонансов р, щ и f0, и были вычислены их интенсивности рождения. Проведено сравнение для двухчастичных аннигиляций на протонах (в вододе) и нейтронах (в дейтерии) и обнаружено согласие между интенсивностями рождения. Определено отношение числа аннигиляций на протоне и нейтроне дейтерия.

Annihilations\bar pn n at rest into final states containing K-mesons

SummaryWe have analysed 2.22·105

The annihilation p - ;n→π+π−π− between 1.0 and 1.6 GeV/c and its comparison with the veneziano model

\bar pn

Study of the reaction from 1.0 to 1.6 GeV/cfrom 1.0 to 1.6 GeV/c

annihilations at rest into final states with two K-mesons and pions. The annihilation rates into three-body (

π−-p interactions at 775 MeV

K\bar K\pi

Evidence for 2γ processes at the ISR

) and four-body (