Gomel, 2009

Hard diffraction: achivements and

questions

I. Satsunkevich, E. Kokoulina, L. Jenkovszky, Dz. Shoukavy, S. Yanush

Gomel, 2009

Abstract

Diffraction in high energy physics is the old subject but diffractive hard scattering is a rather new one. It was discovered 20 years ago. This discovery renewed interest to old diffraction which people had since 50-ties last century. We discuss firstly needed theoretical models and experimental results that have shown new striking diffractive effects. Main new peculiarity of modern diffractions is big rapidity gaps of jet and Z/W productions in p-antip ( pp) reactions and deep inelastic lp- scattering. These experimental results can be described through the exchange of a pomeron with the specific parton content though the pomeron conception is problematic here. But now people even try to use these results in preparing new way (central exclusive production) to search for Higgs boson at Large Hadron Collider.

Gomel, 2009

Lego-Plot 1

Gomel, 2009

Lego-Plot 2

Gomel, 2009

Lego-Plot 3

Gomel, 2009

Lego-Plot 4

Gomel, 2009

Hadron scattering

Gomel, 2009

Longitudinal momentum

Gomel, 2009

Diffractive hard scattering and DIS ep

Gomel, 2009

Rapidity distribution 1

Gomel, 2009

Rapidity distribution 2

Gomel, 2009

Single diffraction

Gomel, 2009

Jet production

QCD

Regge

Gomel, 2009

2 g and systemsqq

a, b, c

Sum rules

Gomel, 2009

Particle collisions

Gomel, 2009

Diffractive DIS

Parton factorization

Gomel, 2009

Central diffraction 2 2 2 2

1 3 0 1 4 0 1 3 0 2 4 0( ) ( )H Hs p p s s p p s t p s t p s

1 1( ) ( )3 4 1 112 1 2 1 2 1 1 2 2 1 2

0 0

( ) ( ( )) ( ( )) ( ( ) ( ) )( ) ( )t tH s sT s s t t g t g t g t t

s s

2( ) 1 0 2 0 02 4t t m t

3 4 1 1

1 2 1 3 2 4

( ) ( )1 11 2 1 2 1 2 1 2

0 0

( ) ( ( )) ( ( )) ( ( ) ( ) )( ) ( )H H t ts sT s s t t g t g t g t t

s s

1 2

1 2 1 2( ) 1( 1) ( )tg g t

1 31 1 2 ( 1)

S S P

1 3

1 3

| | 2( ) ~ ( )g t t

2

1 2

2

H Himm m

m

g e

Gomel, 2009

Electromagnetic diffraction• γγ – fusion H

•Pomeron-pomeron - fusion

* *pp p H p 0.6 fb

0.9 fb

Gomel, 2009

Double diffraction Higgs production

Gomel, 2009

Survival probability

Gomel, 2009

Thanks for your attention!