Hard dif f raction: achivements and questions

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.

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Lego-Plot 1

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Lego-Plot 2

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Lego-Plot 3

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Lego-Plot 4

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Hadron scattering

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Longitudinal momentum

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Diffractive hard scattering and DIS ep

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Rapidity distribution 1

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Rapidity distribution 2

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Single diffraction

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Jet production

QCD

Regge

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2 g and systemsqq

a, b, c

Sum rules

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Particle collisions

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Diffractive DIS

Parton factorization

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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

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Electromagnetic diffraction• γγ – fusion H

•Pomeron-pomeron - fusion

* *pp p H p 0.6 fb

0.9 fb

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Double diffraction Higgs production

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Survival probability

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Thanks for your attention!