x(3872) production in high energy collisions university of são paulo f.s. navarra introduction :...
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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
TetraquarkMeson molecule
cc
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/0404161
Small binding energy
Meson coalescence
Agreement with data !
Meson Molecule
Tetraquark
S.J. Brodsky, D.S. Hwang, R.F. Lebed, arXiv:1406.7281
Diquark-antidiquark picture
Non-relativistic potential
Agreement with data !
All approaches work…
QCD sum rules: C.M. Zanetti, M. Nielsen, R.D. Matheus, arXiv:1105.1343
Proton - Proton
Charm quark pairs generated with PYTHIA
Bignamini et al., arXiv:0906.0882
“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:1405.7929
Antideuteron
X(3872)
CMS data
P. Artoisenet, E. Braaten, arXiv:0911.2016
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, 212001 (2011) ; PRC 84, 064910 (2011)
Evolution of the plasma Hadron gasPlasma formation
Charm meson fusion in the final hadron gas phase
X in a hadron gas
Production Absorption
Cross sections from SU(4) effective Lagrangians
Cho and Lee, arXiv:1302.6381, PRC (2013)
Cho and Lee, arXiv:1302.6381
gain loss
Time evolution of the X abundance
Time evolution of the X abundancy
Some processes not included !
Cho and Lee, arXiv:1302.6381
molecule
tetraquark
Martinez Torres, Khemchandani, Navarra, Nielsen, Abreu, arXiv:1405.7583
Anomalous coupling terms
from QCD sum rules
Bracco, Chiapparini, Navarra, Nielsen, arXiv:1104.2864, Prog. Part. Nucl. Phys. (2012)
?
Loop diagrams
Divergences regularized by a cut-off: 700 - 1000 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:1302.6381
improved
new
Without form factors With form factors
Form factors
Cho and Lee, arXiv:1302.6381
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”
✔
Photon induced production
V.P. Goncalves and M.L.L. da Silva, arXiv:1405.6640
C.~M.~Zanetti, M.~Nielsen and R.~D.~Matheus, arXiv:1105.1343
