Contents
1. Introduction 7
2. Large Hadron Collider, Compact Muon Solenoid, and its forward detectors 10
2.1. Large Hadron Collider . . . . 10
2.1.1. Large Hadron Collider in Run1 . . . . 11
2.2. Compact Muon Solenoid . . . . 12
2.2.1. Barrel and endcaps detectors . . . . 14
2.2.2. Hadronic Forward calorimeter . . . . 17
2.2.3. CASTOR calorimeter . . . . 20
2.2.4. Other forward detectors . . . . 22
2.2.5. Trigger . . . . 24
2.2.6. Software and computing . . . . 26
3. Underlying event 28 3.1. Underlying event description . . . . 28
3.2. Multiple parton interactions . . . . 30
3.2.1. Multiple parton interactions in PYTHIA . . . . 31
3.2.2. Multiple parton interactions in HERWIG++ . . . . 34
3.3. Energy flow in Hadronic Forward calorimeter . . . . 36
3.4. Energy flow in CASTOR calorimeter . . . . 45
3.5. Charged tracks multiplicity in events with a high-pTleading object . . . . 51
4. Forward jets 55 4.1. QCD evolution . . . . 55
4.1.1. DGLAP evolution equations . . . . 55
4.1.2. BFKL evolution equations . . . . 56
4.1.3. CCFM evolution equations . . . . 57
4.2. Jets in QCD . . . . 58
4.3. Jet finding algorithms . . . . 59
4.3.1. The cone algorithms . . . . 60
4.3.2. The sequential recombination algorithms . . . . 61
4.4. Jet energy corrections . . . . 62
4.5. Inclusive forward jets . . . . 64
4.6. Forward–central jets . . . . 72
4.7. DijetK-factor . . . . 74
4.8. Mueller–Navelet jets . . . . 79
6 Forward Physics. . .
5. Soft and hard diffraction 87
5.1. Diffractive interactions . . . . 87
5.1.1. Soft diffraction . . . . 89
5.1.2. Hard diffraction . . . . 91
5.2. Soft diffractive processes inppcollisions at 7 TeV measured with the CMS detector . . . . 93
5.2.1. Topologies of diffractive events in detector . . . . 94
5.2.2. Forward and central large rapidity gaps cross sections . . . . 97
5.2.3. Single diffractive and double diffractive dissociation cross sections . . . . 99
5.2.4. Pseudorapidity gap cross section . . . . 102
5.3. Hard diffractive processes inppcollisions at 7 TeV measured with the CMS experiment . . . . 102
5.3.1. Hard diffractive dijet production . . . . 102
5.3.2. Hard diffractiveWandZbosons production . . . . 108
5.3.3. Jet-gap-jet production . . . . 112
6. Exclusive production 117 6.1. Central exclusive production mechanisms . . . . 117
6.1.1. Pomeron–pomeron interactions . . . . 117
6.1.2. Photon–photon interactions . . . . 118
6.1.3. Pomeron–photon interactions . . . . 120
6.2. Central exclusive production Run1 results from CMS . . . . 120
6.2.1. Measurement of the exclusiveγγ → µ+µ−production . . . . 120
6.2.2. Measurement of the exclusiveγγ → e+e−production . . . . 123
6.2.3. Search for the exclusivegg → γγproduction . . . . 127
6.2.4. Exclusiveγγ → W+W−production and constraints on anomalous quartic gauge couplings . . . . . 130
6.2.5. Exclusiveπ+π−production . . . . 136
7. Summary 140
Bibliography 143
