Determination of f0(980) structure by fragmentation functions

1
Determination of f0(980) structure by
fragmentation functions

• M. Hirai (Juntendo)
• CollaboratorsS. Kumano(KEK), M. Oka(TiTech), K.
  Sudoh(KEK)
• arXiv0708.1816 hep-ph
• 2007, Nov. 13 _at_RCNP

2
Contents

• Introduction
• Fragmentation functions
• Possible f0(980) configurations
• Global analysis
• Results discussion
• Behavior of obtained FFs
• 2nd moments of FFs
• Summary

3
Introduction

• Internal structure of exotic hadrons
• Parton distribution functions (PDFs)
• Measured by deeply inelastic scattering (DIS )
  experiments
• Need stable targets (ex. proton)
• Exotic hadron ?
• Decay
• Short life time, no stable target
• Produced hadrons in ee- scattering
• p, k, p, a0, f0, et al.
• Fragmentation functions (FFs)
• Information about internal structure of produced
  hadrons

4
Fragmentation Functions (FFs)

• Information of hadronization
• Containing no perturbative object
• Determined by a global analysis with experimental
  data in ee?? hX
• Similar behavior to PDFs
• Favored FF like valence quarks
• A constituent of produced hadrons
• Peak position at medium and large-z
• Disfavored FF like sea quarks
• Peak position at small-z

5
Global analysis of FF

• Cross sections observable
• DGLAP equation
• Scale QmFmR ?s center of mass energy

Coefficient Function calculable in pQCD
Fragmentation Function extracted from
experiments
6
Fragmentation functions of f0(980)

• Functional form of initial distributions at Q02
• Constraint condition
• 2nd moment should be finite and less than 1

7
Possible f0(980) configurations
8
Results

• c2/d.o.f. 0.907
• Total of data 23
• Tetra quark configuration
• Becoming favored FFs for light and strange quarks
• Peak position at large-z (z0.85)
• zumax zsmax
• SS configuration
• Mu/Ms0.43 ? 6.73
• Mu lt Ms
• Large uncertainty
• Need precise measurements to reduce their huge
  uncertainties

• 2nd moments
• Mu0.0012 ? 0.0107
• Ms0.0027 ? 0.0183
• Mg0.0090 ? 0.0046

9
Summary

• Internal structure of the exotic hadron from
  fragmentation functions
• Global analysis of FFs with the data of the
  f0(980) production
• Favored disfavored FFs valence sea quarks
• Peak position zmax
• Relation between the 2nd moments of FFs
• Intuitive estimation of order counting for the
  f0(980) production in various quark
  configurations
• Indicating tetra-quark and ss configuration
• Tetra-quark peak position of the up(down)
  strange quark FFs
• SS relation of the 2nd moments
• Huge uncertainties of the FFs and 2nd moments
• Low accuracy of experimental data
• Need precise measurements from Bell, BaBar
  experiments
• Model predictions for the FFs
• Relation between behavior of FFs and quark
  configurations