Probing the quark condensate by means of ππ scattering
نویسنده
چکیده
The available experimental information is consistent with the Weinberg predictions for the threshold parameters of ππ-scattering. The data, however, only test those relations that are insensitive to the quark masses mu and md. Recent theoretical progress leads to remarkably sharp predictions for the behaviour of the Sand P-wave phase shifts in the elastic region – one of the very few low energy phenomena in QCD, where theory is ahead of experiment and where new precision data would subject the theory to a crucial test.
منابع مشابه
K e 4 decays and Wigner cusp Contribution to the proceedings of HQL 06 , Munich , October 16 th - 20 th 2006
The single-flavour quark condensate 〈0 |qq| 0〉 is a fundamental parameter of χPT , determining the relative size of mass and momentum terms in the expansion. Since it can not be predicted theoretically, its value must be determined experimentally, e.g. by measuring the ππ scattering lengths, whose values are predicted very precisely within the framework of χPT , assuming a big quark condensate ...
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