1. Target Fragmentation and Fracture Functions an introduction
tools to handle target fragmentation in semi- inclusive
deep inelastic scattering
L. Trentadue Semi-Inclusive Reactions (SIR) Workshop 2005 Session: Target Fragmentation
Friday, May 20, 2005
presented by Misha Osipenko

2. Semi-inclusive processpT
transverse
momentum 

3. Hadron is emitted from the struck quark after absorption of
Semi Inclusive Deep Inelastic Scattering
Current Fragmentation
Hadron is emitted from
the struck quark
after absorption of
the virtual photon

4. pT>>QCD>0 Hadrons may also come from elsewhere !
Semi Inclusive Deep Inelastic Scattering
Target Fragmentation
Fracture Function
pT>>QCD>0
Fracture Functions = Fragmentation + structure

5. The combination of the Fracture Function with the target-Fragmentation evolution
gives the evolution equation:
Homogeneus ( usual Altarelli Parisi type) term + Inhomogeneus term +

6. 1) Fracture Functions satisfy unitarity
Several properties:
1) Fracture Functions satisfy unitarity
2) Fracture Functions factorize
3) Extended M(x,z,t,Q2)-Fracture Functions satisfy Gribov-Lipatov-Altarelli-Parisi type evolution equations

7. Applications: Diffraction: s t
Diffractive structure functions represent asymptotic limit of the fracture functions

9. Observed diffractive cross section demonstrates Q2 behavior similar to that expected from pQCD.

10. Next-to-leading Fracture Functions
Q2=4.2 GeV2
x=0.495 LO
NLO

11. Other interesting applications and developments:
LEPTO event generator exhibits target fragmentation contribution amplified in case of polarization asymmetries.
Additional term can
reach 10%

12. Fracture Functions : spin dependent
Real scale in the target-current fragmentation separation is t, which can be small also at large Q2 or invariant mass s (HERMES, NOMAD).
Fracture functions naturally generates T-odd SSA.

13. Fracture Functions Future:
As Misha (Osipenko) will show to you later in this session Jlab experiments may give some further insights hopefully in target fragmentation in SIDIS
and
further assess the combined
current + target
final state description

14. Fracture Functions an introduction
tools to handle target fragmentation
L. Trentadue Semi-Inclusive Reactions (SIR) Workshop 2005 Session: Target Fragmentation
Friday, May 20, 2005
presented by Misha Osipenko

15. + DGLAP evolution equation with standard splitting functions
Momentum sum rule
Process independent definition
Hadron-hadron
collisions
N1+N2hX +
In assumption of the factorization