LeadingLeading Effects in the Effects in the Spectra Spectra

ofof cc andand antianticc

Produced inProduced in - - p, pp p, pp andand - -

p p InteractionsInteractions..

Olga Piskounova,P.N.Lebedev Physical Institute,

Moscow

Quark-Gluon String ModelQuark-Gluon String Model

O.PiskounovaDIS03

Valence Quark Distributons in QGSM

O.PiskounovaDIS03

Inclusive production cross section of hadrons H is written as a sum over n-Pomeron cylinder diagrams:

Distribution functions of c in -p collisions are given by:

Fragmentation diagramsFragmentation diagrams

Diquark Fragmentation Diquark Fragmentation Function and String Junction Function and String Junction TransferTransfer

Diquark fragmentation function includes the constant af

c that can be interpreted as

“leading” paremeter:

where the term z2R(0)-2N(0) means the

probability for diquark to have z close to 0.Fragmentation function of string junction is of

the similar form:

whereSJ(0)=0,5. O.PiskounovaDIS03

D meson asymmetry in D meson asymmetry in pp

O.PiskounovaDIS03

A=(N D- -N D+ /(N D- +N D+ )

c c /anti/anticc asymmetry in asymmetry in pp

O.PiskounovaDIS03

c c /anti/anticc asymmetry in asymmetry in pp

O.PiskounovaDIS03

ConclusionsConclusions

The nonzero baryon/antibaryon asymmetry in pion reaction is sensitive to the features of baryon charge transfer by the proton string junction

The charmed baryon/antibaryon spectra were

discribed with the same leading fragmentation parameter af=0.006

There is no need to involve “intrinsic charm” in

the calculation of charmed baryon spectra at the up-to-date level of experimental data

O.PiskounovaDIS03