ΔΔ excitation in proton–proton induced π⁰π⁰ production

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• 作者：T. Skorodko ; M. Bashkanov ; D. Bogoslawsky ; H. Calé ; n ; H. Clement ; E. Doroshkevich ; L. Demiroers ; C. Ekströ ; m ; K. Fransson ; L. Gustafsson ; B. Hö ; istad ; G. Ivanov ; M. Jacewicz ; E. Jiganov ; T
• 关键词：&#x394 ; &#x394 ; excitation ; Two-pion production ; &#x3c0 ; -exchange ; &#x3c1 ; -exchange
• 刊名：Physics Letters B
• 出版年：2011
• 出版时间：10 January 2011
• 年：2011
• 卷：695
• 期：1-4
• 页码：115-123
• 全文大小：704 K

文摘

Exclusive measurements of the pp→ppπ⁰π⁰ reaction have been performed at CELSIUS/WASA at energies from threshold up to T_p=1.3 GeV. Total and differential cross sections have been obtained. Here we concentrate on energies T_p1 GeV, where the ΔΔ excitation becomes the leading process. No evidence is found for a significant ABC effect beyond that given by the conventional t-channel ΔΔ excitation. This holds also for the double-pionic fusion to the quasibound ²He. The data are compared to model predictions, which are based on both π- and ρ-exchange. Total and differential cross sections are at variance with these predictions and call for a profound modification of the ρ-exchange. A phenomenological modification allowing only a small ρ-exchange contribution leads to a quantitative description of the data.