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The nature of X(3900) and recognition of open charm effects. Qian Wang IHEP, CAS. In collaboration with Gang Li, Xiao-Hai Liu and Qiang Zhao. Outline. Motivation Methods and results Other implications of open charm scenario Summary. Motivation. Conventional hadrons. Meson. Baryon.
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The nature of X(3900) and recognition of open charm effects Qian Wang IHEP, CAS In collaboration with Gang Li, Xiao-Hai Liu and Qiang Zhao QNP2012, Palaiseau
Outline • Motivation • Methods and results • Other implications of open charm scenario • Summary QNP2012, Palaiseau
Motivation • Conventional hadrons Meson Baryon Multi-faces of QCD: Exotic hadrons beyond conventional Quark Model Hybrid Glueball Tetra-quark Hadronic molecule The study of hadron structures and hadron spectroscopy should deepen our insights into the Nature of strong QCD. QNP2012, Palaiseau
Motivation Charmonium spectrum QNP2012, Palaiseau
Heavy quarkonium: progress, puzzle and opportunities. Eur. .Phys.J C71, 1534(2011) QNP2012, Palaiseau
Motivation Belle Collaboration, Phys. Rev., D77(2008)011103 What is X(3900)? Open charm effects in the cross section. Yuan-Jiang Zhang and Qiang Zhao, Phys.Rev., D81(2010)034011 Whether the same mechanism plays a role in other processes? Is there direct evidence to establish it as a dynamical mechanism? QNP2012, Palaiseau
Methods and results The hadron loop model or the coupled channel effect Qian Wang etc, hep-ph/ 1202.3026 Xiao-Hai Liu etc, Phys. Rev., D81(2010)014017 Yuan-Jiang Zhang etc, Phys.Rev.Lett., 17(2009)172001 Feng-Kun Guo etc., Phys.Rev., D83(2011)034013 Gang Li and Qiang Zhao, Phys.Rev.D84(2011)074005 Feng-Kun Guo and Ulf-G Meissner, Phys.Rev.Lett., 108(2012)112002 mixing, Talk by Xiao-Gang Wu The mass shift in charmonium, E.Eichten etc., Phys.Rev., D17(1987)3090 …… QNP2012, Palaiseau
Methods and results Long-range processes in Qian Wang, Xiao-Hai Liu and Qiang Zhao, Phys.Rev., D84(2011) 014007 QNP2012, Palaiseau
VMD gives the form of virtual photon coupling to vector meson The effective coupling can be extracted from the width of vector to lepton pair. Methods and results The effective Lagrangians for charmonium coupling to charmed mesons and light meson coupling to charmed mesons are extracted from heavy quark symmetry and chiral symmetry. Xiao-Hai Liu etc., PRD81(2010)014017, H.Y.Cheng etc., PRD71(2005)014030 R.Casalbuoni etc., PR281(1997)145 Taking into account the off-shell effect of the exchanged charmed meson between the final mesons, we include the dipole form factor . Qian Wang, Xiao-Hai Liu and Qiang Zhao, Phys.Rev., D84(2011) 014007 QNP2012, Palaiseau
(b) (a) Methods and results For the isospin-violating J/0 production: QNP2012, Palaiseau
The parameter is determined by this cross section. Methods and results Cross section lineshape of QNP2012, Palaiseau
Methods and results Direct evidence for open charm effects in the cross section lineshape of QNP2012, Palaiseau
Methods and results Possible further evidence for open charm effects in the cross section lineshape of QNP2012, Palaiseau
This is our starting point. Other implications of open charm scenario The long-standing puzzle: Color-octet model,Y.Q. Chen and E.Braaten, Phys.Rev.Lett.80(1998) 5060 Vector meson mixing, L.J.Glavelli etc., Phys.Rev.,D28(1983)2767, S.S. Pinsky, Phys.Lett., B236(1990)479 Final-state interactions, X.Q. Li etc., Phys.Rev., D55,(1997)1421, M.Suzuki.,Phys.Rev.D57(1998)5717 Vector glueball near J/Ψ, C.T. Chan etc., Nucl.Phys., A675(2000367C, Y.F.Gu etc., Nucl.Phys., A675(2000)4040C Intrinsic charm in light mesons,S.J.Brodsky etc., Phys.Rev.Lett.78(19997)4682 Light-quark mixing effects,T.Feldmann and P.Kroll, Phys.Rev.,D62(2000)074006 Interferences between the electromagnetic and strong interactions …… QNP2012, Palaiseau
Overall fit indicates the suppression of strong interaction in Ψ’ decays. Other implications of open charm scenario A.Seiden etc., PRD38(1988)824, M.Suzuki, PRD63(2001)054021, Gang Li etc., J.Phys.G35(2008)055002, Qiang Zhao etc., PLB645(2007)173 QNP2012, Palaiseau
Other implications of open charm scenario Qian Wang, Gang Li and Qiang Zhao, Phys. Rev. D85, 074015. QNP2012, Palaiseau
Other implications of open charm scenario Qian Wang, Gang Li and Qiang Zhao, Phys. Rev. D85, 074015. QNP2012, Palaiseau
Thank you for your attention! Summary • X(3900) may be due to open charm effects instead of a new charmonium state. • Such a mechanism can be directly examined in • Open charm effects could be essential for understanding the long-standing “ puzzle”. QNP2012, Palaiseau