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On the origin of small-p T direct electrons in pp collisions

  • Published:
Il Nuovo Cimento A (1965-1970)

Summary

The possible charm origin of the rapid increase at smallp T of the pp electron yield is discussed in the light of recent e+e− data bearing on charm decays. The charm decay electron spectrum required for a quantitative interpretation of the effect is found to be significantly consistent with the momentum distribution of the e+e− anomalous electron-plus-hadron events observed at DORIS. The amount of the charm cross-section times the branching ratio,B e σ, demanded by the pp → e + X data is compatible with existing experimental upper limits, once the recent experimental information on charm decays is taken into account. Since charm-originated leptons are limited to very small Feynmanx, there is no conflict with the reported evidence for a pair origin of near-forward produced leptons. See note added in proof for revised conclusions based on new e+e− data.

Riassunto

Si discute la possibile origine da charm della rapida crescita a piccolip T della produzione pp di elettroni alla luce di recenti dati e+e− riguardanti i modi di decadimento del charm. Si trova che lo spettro d’elettrone nel decadimento del charm che viene richiesto per una interpretazione quantitativa dell’effetto è significativamente consistente con la distribuzione in momento degli eventi anomali elettrone più adroni in collisioni e+e− osservati a DORIS. L’entità del prodotto della sezione d’urto di produzione del charm per il rapporto di decadimento,B e σ, richiesto dai dati pp → e + X è compatibile con gli esistenti limiti superiori sperimentali, una volta che la recente informazione sperimentale sui decadimenti del charm è tenuta debitamente in conto. Dato che i leptoni originati dal charm sono limitati ax di Feynman molto piccoli, non vi è conflitto con la riportata evidenza di una origine da coppie dei leptoni prodotti vicino all’avanti. Vedi la nota aggiunta in bozza per una modifica delle conclusioni alla luce di nuovi dati e+e−.

Реэюме

В свете недавних e+e−данных, относяшихся к очарованным распадам, обсуждается воэможное происхождение быстрого воэрастания при малыхp T рр злектронного выхода. Получено, что спектр злектронов, обраэованных в реэультате очарованных распадов, требуемый для количественной интерпретации рассматриваемого зффекта, согласуется с импульсным распределением для e+e− аномальных событий, наблюденных на установке ДОРИС. Величина поперечного сечения, умноженная на отнощение ветвей распада, Be σ, требуемая иэ pp→e+X данных, совместима с сушествуюшими зкспериментальными верхними пределами, в том случае, если учитывается недавно полученная зкспериментальная информация. Так как обраэованные лептоны ограничены областью малыхx, то не сушествует противоречий с опубликованными подтверждениями для обраэования пар дептонов вблиэи направления вперед.

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Authors and Affiliations

  1. Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina

    C. Ferro Fontán

  2. Istituto di Fisica Teorica dell’Università, Trieste, Italia

    R. Odorico

  3. Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, Italia

    R. Odorico

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Ferro Fontán, C., Odorico, R. On the origin of small-p T direct electrons in pp collisions. Nuov Cim A 42, 141–159 (1977). https://doi.org/10.1007/BF02730311

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