Introduction

Introduction

Inclusive jet PHP

High Q2 DIS inclusive jets

Jet production at low Q2 Good description within big theoretical uncertainties

Normalised cross sections in DIS Use ratios to reduce the uncertainties 20% reduction in the uncertainties

Running aS

The strong coupling constant aS Precise HERA experimental data + successful pQCD predictions

Dijet PHP: direct vs resolved NLO Frixione, Ridolfi Photon PDFs: Cornet et al. CJK Aurenche et al. AFG04

Dijet PHP: direct vs resolved None of the PDFs gives an adequate description of the data. Higher orders are needed.

Low x jet production • Forward jets • Multijets with special topology • Multijets correlations

Forward jet production at low x Data are above NLO in the regions where difference between LO and NLO is huge

Multijet production + forward jets Including next orders improves the description of the data!

Forward jets with special topology The difference at low-x where the gluon radiation becomes more important

DIS multijet production at low-x • Previously measured multijet production in a wide Q2 range; • Reduced scales for NLOJET++ calculations; • Nice description and extraction of aS Low-x measurement

DIS multijet production at low-x LO - NLO – NNLO in dijet case Trijet NLO as Dijet NNLO in restricted phase space

DIS multijet production at low-x dijets • Nice description of the data; • Huge difference due to NNLO effects. trijets

Summary • Precise jet measurements in PHP and DIS provide useful information on the proton and photon PDFs; • At low-x: • the data demonstrate a big impact of initial gluon radiation; • pQCD predictions reproduce almost all data with significant theoretical uncertainties; • NNLO calculations are needed!

Introduction

Introduction

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Introduction to introduction to introduction to … Optimization

INTRODUCTION/ INTRODUCTION

Introduction

INTRODUCTION

Introduction

Introduction