X(3872) production in high energy collisions University of São Paulo F.S. Navarra Introduction : exotic hadrons Production in pp and AA XIII International Workshop on Hadron Physics

What are exotic hadrons ? What can we learn from them ? Were they observed ? Yes ! In many experiments: e+e-, pp, AA (?) 20 new states ! Best known: X(3872) (PDG) Does the theory (QCD) reproduce the data ? Lattice QCD: so far, results are inconclusive QCD Sum Rules: supports the existence of some of these states Effective Lagrangians: support the existence of some of these states Quark models: reproduce data but have less predictive power Mass spectrum and decay width: QCD at low energies Production: particle production in QCD at high energies. New hadrons: which are not or states. Multiquark systems ! “Wrong masses” and isospin violating decays

Tetraquark Meson molecule c c X (3872) It is possible to get the right mass in different approaches !

X(3872) production

B factories (BELLE, BABAR) : B decays E. Braaten, M. Kusunoki, hep-ph/ Small binding energy Meson coalescence Agreement with data ! Meson Molecule

Tetraquark S.J. Brodsky, D.S. Hwang, R.F. Lebed, arXiv: Diquark-antidiquark picture Non-relativistic potential Agreement with data !

All approaches work… QCD sum rules: C.M. Zanetti, M. Nielsen, R.D. Matheus, arXiv:

Proton - Proton Charm quark pairs generated with PYTHIA Bignamini et al., arXiv: “Roman model” Fragmentation into D mesons pairs Model for weakly binding the D mesons Problem for the molecular approach ! Result: (CDF) Proton-proton colliders: Fermilab, LHC Meson molecule

Antideuteron production: the test of the roman model! A. Guerrieri et al., arXiv: Antideuteron X(3872) CMS data

P. Artoisenet, E. Braaten, arXiv: NRQCD plus rescattering in the final state: molecular approach describes the CDF data ! M. Dall’Osso et al., POS (Beauty 2013) 066 Predictions for the LHC :

Tetraquark ?

Nothing works…

nucleus – nucleus dirty environment (many hadrons produced) deconfined medium: quark-gluon plasma hadron gas phase after reconfinement New production mechanisms ! More charm from the initial state and new charm from thermal gluon fusion X from quark coalescence during the phase transition X from meson-meson fusion in the hadron gas phase Nucleus - Nucleus

X(3872) Quark coalescence during hadronization Quark coalescence Cho et al. ExHIC Collab., PRL 106, (2011) ; PRC 84, (2011)

Evolution of the plasma Hadron gas Plasma formation Charm meson fusion in the final hadron gas phase

X in a hadron gas ProductionAbsorption Cross sections from SU(4) effective Lagrangians Cho and Lee, arXiv: , PRC (2013)

Cho and Lee, arXiv: gain loss Time evolution of the X abundance

Time evolution of the X abundancy Some processes not included ! Cho and Lee, arXiv: molecule tetraquark

Martinez Torres, Khemchandani, Navarra, Nielsen, Abreu, arXiv: Anomalous coupling terms from QCD sum rules Bracco, Chiapparini, Navarra, Nielsen, arXiv: , Prog. Part. Nucl. Phys. (2012) ?

Loop diagrams Divergences regularized by a cut-off: MeV

Fit the tree level calculation to the loop calculation and extract the coupling : loop tree vertex is very important with without

anomalous terms

without with vertex is very important

is the most important process Cho and Lee, arXiv: improved new

Without form factors With form factors Form factors Cho and Lee, arXiv:

Work in progress… Next: go back to the rate equation with new cross sections !

We want to use HIC to know the structure of the X X is produced at the end of the plasma phase by quark coalescence Quark coalescence is sensitive to the X wave function In the hadron phase X can be produced and destroyed EL depend on the internal structure only through the coupling constants This is described by Effective Lagrangians. For tetraquarks coupling constants can be calculated with QCD sum rules Summary Here we have improved the Effective Lagrangian approach

Back up slides

Absorption is stronger than production X production X absorption

pion is the X “killer”

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Photon induced production V.P. Goncalves and M.L.L. da Silva, arXiv:

C.~M.~Zanetti, M.~Nielsen and R.~D.~Matheus, arXiv: