Il Nuovo Cimento A (1965-1970)

, Volume 48, Issue 3, pp 676–685 | Cite as

Absorptive effects in the production process pp→pN\(_{33}^* \)

  • D. P. Roy


The reaction pp→pN\(_{33}^* \) for the incident-momentum range (6–15) GeV/c is studied in the one-pion exchange model, by incorporating the absorption corrections due to other competing channels, following the prescription of Gottfried and Jackson. With a reasonable choice of the final-state scattering parameters, the absorptive effects are found to provide sufficient prunning to the Born amplitude, so as to reproduce the observed forward peak in the angular distribution. The magnitude of the estimated cross-section at 6 GeV/c, however, comes out to be thrice as large as the observed one. Also the predicted cross-section falls somewhat faster with increasing energy as compared to the corresponding experimental quantity. These features are similar to the ones observed earlier for reactions of the type\(\pi p \to \rho \)N* or\(p\bar p \to \)N*N*, where particles with large spins are involved.


Helicity Amplitude Born Term Forward Peak Incident Momentum Born Amplitude 
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Эффекты поглощения в процессе рождения


Изучается реакция pp→pN\(_{33}^* \) в области начальных импульсов (6÷15) ГэВ/с в модели с однопионным обменом, посредством включения поправок поглощения, обусловленных другими конкурирующими каналами, следуя рецепту Гэттфрида и Джексо]qnа. При соответствующем выборе параметров рассеяния для конечного состояния обнаружено, что эффекты поглощения обеспечивают значительное упрощение к Борновской амплитуде, чтобы воспроизвести пик поглощения вперед в угловом распределении. Однако, вычисленна величина поперечного сечения при 6 ГэВ/с в три раза больше, чем наблюдаемая. Также предсказанное поперечное сечение падает несколько быстрее с увеличением энергии, по сравнению с соответствующей экспериментальной величиной. Эти особенности аналогичны особенностям, которые наблюдались раньше в реакциях типр\(\pi p \to \rho \)N* или\(p\bar p \to \)N*N*, в которые входят частицы с большими спинами.


Si studia nel modello a scambio di un pione la reazione pp→pN\(_{33}^* \) per un intervallo di impulsi incidenti di (6÷15) GeV/c, incorporando le correzioni dell'assorbimento dovute ad altri canali competitivi, seguendo le prescrizioni di Gottfried e Jackson. Con una scelta ragionevole dei parametri di scattering dello stato finale, si trova che gli effetti di assorbimento provvedono ad una sufficiente riduzione dell'ampiezza di Born, in modo da riprodurre il picco anteriore osservato nella distribuzione angolare. La grandezza della sezione d'urto stimata a 6 GeV/c, tuttavia, risulta tre volte maggiore di quella osservata. Anche la sezione d'urto predetta decresce un poco piu rapidamente al crescere dell'energia in confronto alla corrispondente grandezza sperimentale. Queste caratteristiche sono analoghe a quelle osservate precedentemente per reazioni del tipo\(\pi p \to \rho \)N* o\(p\bar p \to \)N*N*, in cui sono cointeressate particelle con grandi spin.


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Copyright information

© Società Italiana di Fisica 1967

Authors and Affiliations

  • D. P. Roy
    • 1
  1. 1.Tata Institute of Fundamental ResearchBombay

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