Summary
We derive, in the framework of Glauber theory, the expression of the amplitudes for the semi-coherent excitation of the 2+ (4.4 MeV) level of12C with incident pion and proton beams, including the spin-flip amplitudes in the latter case, using the formalism of harmonic solid tensors. The expressions of the differential cross-section and of the nuclear density matrices are computed and compared with the existing high-energy data. The overall agreement between theory and experimental results for the differential and integrated cross-sections and for the density matrix elements is satisfactory; solving, therefore, a discrepancy of a factor two found by previous authors.
Riassunto
Nel quadro della teoria di Glauber si deriva l’espressione delle ampiezze per il processo di eccitazione semicoerente del livello 2+ (4.4 MeV) del12C con fasci incidenti di pioni e protoni. In quest’ultimo caso si includono le ampiezze di spin flip. Il metodo usato è quello dei tensori armonici solidi. Si calcolano le espressioni delle sezioni d’urto differenziali e delle matrici ensità nucleari, che si confrontano con i dati di alta energia. Si trova un accordo soddisfacente fra teoria e risultati sperimentali, sia per le sezioni d’urto differenziali che per quelle integrate e per le matrici densità; in questo modo si risolve una discrepanza di un fattore due trovata da altri autori.
Реэюме
В рамках теории Глаубера выводится выражение для амплитуд полукогерентного воэбуждения уровня12С (2+, 4.4 МзВ) под действием пионного и протонного пучков, учитывая амплитуды с переворачиванием спина в последнем случае и испольэуя формалиэм гармонических трехмерных тенэоров. Вычисляются выражения для дифференциального поперечного сечения и для матриц ядерной плотности. Полученные реэультаты сравниваются с имеюшимися данными при высоких знергиях. Получается удовлетворительное согласие между теорией и зкспериментальными реэультатами для дифференциального и интегрального поперечных сечений и для злементов матрицы плотности.
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Bertocchi, L., Troncon, C. Hadron-induced semi-coherent scattering and the excitation of the12C(2+, 4.4 MeV) level. Nuov Cim A 45, 238–256 (1978). https://doi.org/10.1007/BF02724666
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DOI: https://doi.org/10.1007/BF02724666