Summary
A study of about 105 proton-proton interactions at\(\sqrt s = 52.5 GeV\) was performed by using the ISR Split Field Magnet. Correlations between particles pairs with like and unlike charges were studied in terms of six variables. The main conclusions are i) the difference in the azimuthal asymmetry parameter between unlike- and like-charge pairs shows up at invariant masses between 500 and 1200 MeV,i.e. in the region of the well-known resonances; ii) a supershort (Δy≤0.5) correlation effect exists for unlike- as well as for like-charge pairs; iii) the azimuthal asymmetry parameter remains positive (back-to-back configurations are preferred) even for every large values of the rapidity variables, independent of the charge configurations. The 105 interactions represent a high statistical sample of events without any sort of trigger bias, such as highp T, multiplicity, or energy.
Riassunto
Si sono studiate circa 105 interazioni protone-protone a\(\sqrt s = 52.5 GeV\) GeV usando lo Split Field Magnet degli ISR. Si sono analizzate le correlazioni tra coppie di particelle di carica elettrica uguale ed opposta in funzione di sei variabili. Le principali conclusioni sono: i) la differenza nel parametro di asimmetria azimutale tra coppie di carica opposta ed uguale si manifesta per valori della massa invariante tra 500 e 1200 MeV, cioè nella regione delle risonanze ben note; ii) esiste un effetto di correlazione delle coppie di carica opposta ed uguale per valori estremamente piccoli di Δy (Δy≤0.5); iii) il parametro di asimmetria azimutale rimane positivo (le configurazioni «back-to-back» sono privilegiate) anche per valori molto grandi di rapidità, indipendentemente dagli stati di carica. Le 105 interazioni studiate costituiscono un campione, ad alta statistica, di eventi senza condizioni particolari di «trigger», come altop T, molteplicità o energia.
Резюме
Проведено изучение 105 протон-протонных взаимодействий при
ГэВ. С помощью шести переменных исследуются корреляции между парами частиц с одинаковыми и неодинаковыми зарядами. Получены следующие результаты: 1) обнаружена разность в параметре азимутальной асимметрии для пар неодинаковых зарядов и для пар одинаковых зарядов при инвариантных массах между 500 и 1200 МэВ, т.е. в области хорошо известных резонансов; 2) обнаружен эффект суперкоротких корреляций (Δy=0.5) для пар неодиноковых зарядов и для пар одиаковых зарядов; 3) параметр азимутальной асимметрии остается положительным даже для очень больших значений переменных быстроты вне зависимости от зарядовой конфигурации. 105 взаимодействий представляют пример высокой статистики событий.
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Basile, M., Cara Romeo, G., Cifarelli, L. et al. Two-body correlations in high-energy proton-proton interactions. Nuov Cim A 39, 441–460 (1977). https://doi.org/10.1007/BF02896547
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DOI: https://doi.org/10.1007/BF02896547