We discuss the effect of the instanton induced, six-fermion effective Lagrangian on the decays of the lightest scalar mesons in the diquark-antidiquark picture. This addition allows for a remarkably good description of light scalar meson decays. The same effective Lagrangian produces a mixing of the lightest scalars with the positive parity q over(q, ̄) states. Comparing with previous work where the q over(q, ̄) mesons are identified with the nonet at 1200-1700 MeV, we find that the mixing required to fit the mass spectrum is in good agreement with the instanton coupling obtained from light scalar decays. A coherent picture of scalar mesons as a mixture of tetraquark states (dominating in the lightest mesons) and heavy q over(q, ̄) states (dominating in the heavier mesons) emerges. © 2008.
A theory of scalar mesons / G., 'T Hooft; G., Isidori; Maiani, Luciano; Polosa, ANTONIO DAVIDE; V., Riquer. - In: PHYSICS LETTERS. SECTION B. - ISSN 0370-2693. - 662:5(2008), pp. 424-430. [10.1016/j.physletb.2008.03.036]
A theory of scalar mesons
MAIANI, Luciano;POLOSA, ANTONIO DAVIDE;
2008
Abstract
We discuss the effect of the instanton induced, six-fermion effective Lagrangian on the decays of the lightest scalar mesons in the diquark-antidiquark picture. This addition allows for a remarkably good description of light scalar meson decays. The same effective Lagrangian produces a mixing of the lightest scalars with the positive parity q over(q, ̄) states. Comparing with previous work where the q over(q, ̄) mesons are identified with the nonet at 1200-1700 MeV, we find that the mixing required to fit the mass spectrum is in good agreement with the instanton coupling obtained from light scalar decays. A coherent picture of scalar mesons as a mixture of tetraquark states (dominating in the lightest mesons) and heavy q over(q, ̄) states (dominating in the heavier mesons) emerges. © 2008.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
