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Advances in High Energy Physics
Volume 2019, Article ID 3465159, 7 pages
Research Article

Unquenching the Quark Model in a Nonperturbative Scheme

Grupo de Física Nuclear and Instituto Universitario de Física Fundamental y Matemáticas (IUFFyM), Universidad de Salamanca, E-37008 Salamanca, Spain

Correspondence should be addressed to David R. Entem; se.lasu@metne

Received 8 January 2019; Revised 17 March 2019; Accepted 7 April 2019; Published 2 May 2019

Guest Editor: Xian-Wei Kang

Copyright © 2019 Pablo G. Ortega et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The publication of this article was funded by SCOAP3. The publication of this article was funded by SCOAP3.


In recent years, the discovery in quarkonium spectrum of several states not predicted by the naive quark model has awakened a lot of interest. A possible description of such states requires the enlargement of the quark model by introducing quark-antiquark pair creation or continuum coupling effects. The unquenching of the quark models is a way to take these new components into account. In the spirit of the Cornell Model, this is usually done by coupling perturbatively a quark-antiquark state with definite quantum numbers to the meson-meson channel with the closest threshold. In this work we present a method to coupled quark-antiquark states with meson-meson channels, taking into account effectively the nonperturbative coupling to all quark-antiquark states with the same quantum numbers. The method will be applied to the study of the X(3872) resonance and a comparison with the perturbative calculation will be performed.