New spectrum and condensate in two dimensional QCD

The boson mass and the condensate in two dimensional QCD with SU(Nc) colors are numerically evaluated with the Bogoliubov vacuum. It is found that the boson mass is finite at the massless limit, and it is well described by the phenomenological expression MNc = 2 3 √ Ncg 3π for large Nc. Also, the condensate values agree very well with the prediction by the 1/Nc expansion. The validity of the naive light cone method is examined, and it turns out that the light cone prescription of the boson mass with the trivial vacuum is accidentally good for QED2. But it is not valid for QCD2. Further, at the massless fermion limit, the chiral symmetry is spontaneouly broken without anomaly, and the Goldstone theorem does not hold for QCD2. PACS numbers: 11.10.Kk, 11.15.-q, 03.70.+k, 11.30.-j, 11.30.Rd e-mail: [email protected] e-mail: [email protected] e-mail: [email protected]