Bochum 2009 – wissenschaftliches Programm
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HK: Fachverband Hadronen und Kerne
HK 61: Fundamental Symmetries
HK 61.2: Vortrag
Mittwoch, 18. März 2009, 17:00–17:15, H-ZO 70
Wigner and Serber symmetries for Nucleon-Nucleon Interactions and the large Nc limit. — •Alvaro Calle Cordon and Enrique Ruiz Arriola — Universidad de Granada, Granada, Spain
Wigner symmetry in nuclear physics provides a unique example of a non-perturbative long distance symmetry, a symmetry strongly broken at short distances. We analyse the consequences of such a concept within the framework of One Boson Exchange Potentials in NN scattering and keeping the leading Nc contributions. Phenomenologically successful relations between singlet 1S0 and triplet 3S1 scattering phase shifts are provided in the entire elastic region. We establish symmetry breaking relations among non-central phase shifts which are successfully fulfilled by even-L partial waves and strongly violated by odd-L partial waves, in full agreement with large Nc requirements. The Serber force has relative orbital parity symmetry and requires the vanishing NN interactions in partial waves with odd angular momentum. We illustrate how is well fulfilled for spin triplet states and violated for even singlet states. We show that interpreted as a long distance symmetry this feature can be made plausible from a large Nc perspective. A prerequisite for this is the identity of the scalar and vector meson resonance masses. While these masses arise as poles on the Second Riemann in ππ scattering, we find that within the large Nc expansion the corresponding Yukawa masses correspond instead to their location as Breit-Wigner resonances.