Summary
\(\bar pn\) annihilations into three and five charged mesons with or without neutrals have been studied in order to measure the contributions of the various final states to the 5.5 mb enhancement discovered in the totalI=1\(\bar {\mathcal{N}}\mathcal{N}\) cross-section at 2190 MeV total c.m. energy. Fits have been performed to the cross-sections as functions of the incident-\(\bar p\); momentum with background plus a resonant term. The fits show enhancements in several final states, the statistically most significant one being in the reaction\(\bar pn \to \pi ^ + 2\pi ^ - \) ((0.51 ± 0.13) mb over a background of 1.4 mb). Less significant effects are also found in all other pionic annihilation final states regardless of theirG-parity.
Riassunto
Si sono studiate le annichilazioni\(\bar pn\) in tre e cinque mesoni carichi con o senza particelle neutre per misurare i contributi dei vari stati finali all’incremento di 5.5 mb scoperto nella sezione d’urto totaleI=1\(\bar {\mathcal{N}}\mathcal{N}\) a 2190 MeV di energia totale nel centro di massa. Si sono effettuate approssimazioni alle sezioni d’urto in funzione dell’impulso del\(\bar p\) incidente costituite dal fondo più un termine di risonanza. Le approssimazioni evidenziano incrementi in numerosi stati finali, il più significativo dei quali si ha nella reazione\(\bar pn \to \pi ^ + 2\pi ^ - \) ((0.51 ± 0.13) mb su un fondo di 1.4 mb). Si trovano effetti meno significativi anche in tutti gli altri stati finali pionici di annichilazione a prescindere dalla loro paritàG.
Реэюме
Было проведено исследование\(\bar pn\) аннигиляций в три и пять эаря-женных меэонов с или беэ нейтральных частиц, для того чтобы иэмерить вклады раэличных конечных состояний в 5.5мб увеличение, обнаруженное в полномI=1\(\bar {\mathcal{N}}\mathcal{N}\) поперечном сечении при полной знергии 2190 МзВ в системе центра масс. Проводится подгонка поперечных сечений, как функций падаюшего импульса\(\bar p\), с фоном плюс реэонансный член. Подгонка обнаруживает увеличение в некоторых конечных сос-тояниях, причем, статистически наиболее сушественным является одно иэ них в реакции\(\bar pn \to \pi ^ + 2\pi ^ - \) ((0.51 ± 0.13)мб свыще фона 1.4 мб). Менее сушественные зффекты обнаружены во всех других пионных конечных состояниях реакции аннигиляции, неэависимо от ихG-четности.
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Huesman, R.H., Alston-Garnjost, M., Ross, R.R. et al. Experimental study of\(\bar pn\) annihilations between 1.0 and 1.6 GeV/cannihilations between 1.0 and 1.6 GeV/c. Nuov Cim A 25, 91–109 (1975). https://doi.org/10.1007/BF02735612
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DOI: https://doi.org/10.1007/BF02735612