Issues and Opportunities in Exotic Hadrons

The last few years have been witness to a proliferation of new results concerning heavy exotic hadrons. Experimentally, many new signals have been discovered that could be pointing towards the existence of tetraquarks, pentaquarks, and other exotic configurations of quarks and gluons. Theoretically, advances in lattice field theory techniques place us at the cusp of understanding complex coupled-channel phenomena, modelling grows more sophisticated, and effective field theories are being applied to an ever greater range of situations. It is thus an opportune time to evaluate the status of the field. In the following, a series of high priority experimental and theoretical issues concerning heavy exotic hadrons is presented.

[1]  A. Guerrieri,et al.  Probing the nature of Z c (′) states via the η c ρ decay , 2014, 1409.3551.

[2]  C. Morningstar,et al.  Improved stochastic estimation of quark propagation with Laplacian Heaviside smearing in lattice QCD , 2011, 1104.3870.

[3]  E. Eichten,et al.  Charmonium: Comparison with Experiment , 1980 .

[4]  J. Kuti,et al.  Fine structure of the QCD string spectrum. , 2002, Physical review letters.

[5]  E. Eichten,et al.  Interplay of Confinement and Decay in the Spectrum of Charmonium , 1976 .

[6]  G. Krein,et al.  J/Ψ mass shift in nuclear matter , 2010, 1007.2220.

[7]  R. Edwards,et al.  Excited meson radiative transitions from lattice QCD using variationally optimized operators , 2015, 1501.07457.

[8]  C. Lang,et al.  D*(s0)(2317) meson and D-meson-kaon scattering from lattice QCD. , 2013, Physical review letters.

[9]  Diquark-antidiquarks with hidden or open charm and the nature of X(3872) , 2004, hep-ph/0412098.

[10]  Brian T Sutcliffe,et al.  On the quantum theory of molecules. , 2012, The Journal of chemical physics.

[11]  N. Törnqvist,et al.  HEAVY c anti-c AND b anti-b QUARKONIUM STATES AND UNITARITY EFFECTS , 1984 .

[12]  T. Hilger,et al.  Masses of J P C =1 -+ exotic quarkonia in a Bethe-Salpeter-equation approach , 2015, 1503.08697.

[13]  Ericka Stricklin-Parker,et al.  Ann , 2005 .

[14]  C. Lang,et al.  $D_{s}$ mesons with $DK$ and $D^{*}K$ scattering near threshold , 2014, 1403.8103.

[15]  A. Polosa,et al.  Z (4430) and a new paradigm for spin interactions in tetraquarks , 2014, 1405.1551.

[16]  B-meson gateways to missing charmonium levels. , 2002, Physical review letters.

[17]  L. Gibbons,et al.  Beam simulation : beam transport in the bunch compressor main-linacs and beam delivery systems , beam halo modeling and transport , and implementation as a diagnostic tool for commissioning and operation Personnel and Institution ( s ) requesting funding , 1994 .

[18]  for the BaBar Collaboration , 2001 .

[19]  T. Aushev,et al.  Search for lepton-flavor-violating tau-lepton decays to ‘γ at Belle The BELLE collaboration , 2001 .

[20]  S. Brodsky,et al.  Dynamical picture for the formation and decay of the exotic XYZ mesons. , 2014, Physical review letters.

[21]  E. Eichten,et al.  Erratum: Charmonium: The model , 1980 .

[22]  R. Hayano,et al.  Hadron properties in the nuclear medium , 2008, 0812.1702.