Light-quark mass behaviour of the X(3872) as a molecular state

¹ Institut für Theoretische Physik II, Ruhr-Universität Bochum, D-44780 Bochum, Germany
² Institute for Theoretical and Experimental Physics, B. Cheremushkinskaya 25, 117218 Moscow, Russia
³ Forschungszentrum Jülich, Institute for Advanced Simulation, Institut für Kernphysik and Jülich Center for Hadron Physics, D-52425 Jülich, Germany
⁴ Tbilisi State University, 0186 Tbilisi, Georgia
⁵ National Research Nuclear University MEPhI, 115409, Moscow, Russia
⁶ Moscow Institute of Physics and Technology, 141700, Dolgoprudny, Moscow Region, Russia

^a e-mail: vadim.baru@tp2.rub.de
^b e-mail: evgeny.epelbaum@ruhr-uni-bochum.de
^c e-mail: arseniy.filin@tp2.rub.de
^d e-mail: jgegelia@hotmail.com
^e e-mail: nefediev@itep.ru

Published online: 25 March 2016

Abstract

Chiral extrapolations of the binding energy of the X(3872) molecular state are investigated using an explicitly renormalizable framework free of finite cut-off artefacts. Insights into the binding mechanisms are discussed: if the X is less bound with the growing pion mass, its binding energy is governed by the explicit pion mass dependence from one-pion exchange; an opposite behaviour would indicate the importance of the pionmass dependent short-range interactions, in addition to pionic effects. The important role of the three-body DD̄π dynamics is emphasised.