کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
9851492 | 1527295 | 2005 | 23 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
QCD sum rules at finite density in the large-Nc limit: the coupling of the Ï-nucleon system to the D13(1520)
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
فیزیک و نجوم
فیزیک هسته ای و انرژی بالا
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چکیده انگلیسی
QCD sum rules are studied for the vector-isovector current at finite baryon density in the limit of large number of colors Nc. For the condensate side it is shown that in this limit the four-quark condensate factorizes also for the finite density case. At the hadronic side the medium dependence is expressed in terms of the current-nucleon forward scattering amplitude. Generalizing vector meson dominance we allow for a direct coupling of the current to the nucleon as well as a coupling via the Ï meson. We discuss the Nc dependence of (a) modifications of the pion cloud of the Ï meson, (b) mixing with other mesons (in particular a1 and Ï) and (c) resonance-hole excitations RNâ1. We show that only the last effect survives in the large-Nc limit. Saturating the sum rules with a simple hadronic ansatz which allows for the excitation of the D13(1520) we determine the coupling of the latter to the Ï-nucleon and the photon-nucleon system. These couplings are hard to determine from vacuum physics alone.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Nuclear Physics A - Volume 747, Issues 2â4, 24 January 2005, Pages 425-447
Journal: Nuclear Physics A - Volume 747, Issues 2â4, 24 January 2005, Pages 425-447
نویسندگان
Stefan Leupold, Marcus Post,