Collider Physics

Perturbative QCD is the main tool used at the LHC to make precise predictions for the huge variety of processes seen in the detectors, and is thus a vital ingredient in the discovery of new physics. Modern research is conducted on a number of fronts:

Fixed-order calculations: in recent years significant progress was made in automating next-to-leading order computations, but many next-to-next-to-leading calculations are still very challenging.

Gauge theory amplitudes: there has been significant progress in understanding the properties of scattering amplitudes, and developing new techniques to compute them. Our group's research focuses on the long-distance singularity structure of amplitudes. Another promising avenue is the relation between quantum gravity and gauge theory amplitudes.

-  Resummation: Fixed-order calculations refer to an expansion in the coupling constant as a single small parameter; however whenever there is a large hierarchy of scales, there are ways to sum up dominant corrections to all orders in perturbation theory. An example is the ongoing development of the High Energy Jets approach (HEJ) that exploits the known behaviour of amplitudes in the high-energy limit to perform resummation of cross sections with a large number of partons.

Parton densities: New techniques to extract parton densities using Monte Carlo techniques and neural networks (NNPDF) are currently transforming the field: this is important because reliable precise PDFs are an essential ingredient of every hard cross-section prediction at the LHC. NNPDFs were used by both ATLAS and CMS in their recent analyses leading to the Higgs discovery.

 

Researchers

Richard Ball

+44 (0)131 650 5248

Enrico Bothmann

+44 (0)131 650 5304

Luigi Del Debbio

+44 (0)131 650 5212

Einan Gardi

+44 (0)131 650 6469

Donal O'Connell

+44 (0) 131 6505264

Alexander Ochirov

+44 (0) 131 6505244

Tiziano Peraro

+44 (0)131 650 5239

Jennifer Smillie

+44 (0)131 650 5247

Leonardo Vernazza

+44 (0)131 650 5244

Associates

Vittorio Del Duca

LNF, Frascati; ETH Zurich

+39 069 403 2764

Lance Dixon

SLAC, Stanford University

+1 650 926 2627

Claude Duhr

Université catholique de Louvain; CERN

Keith Ellis

IPPP Durham

+44-(0)191-33-43621

Stefano Forte

University of Milan

+39 025 031 7276

Gudrun Heinrich

Max Planck Institute for Physics, Munich

+49 89 323 54 - 284

Michael Krämer

Aachen University

+49 (0)241 80 27047

Eric Laenen

Nikhef, Amsterdam

+31 20 592 5127

Lorenzo Magnea

University of Turin

+39 11 670 7204

Tilman Plehn

Heidelberg University

+49 622 154 9104

Affiliates

Jeppe Andersen

University of Durham

+44 (0)191 334 3564

Simon Badger

PhD Students

Christian Brønnum-Hansen

+44 (0)131 650 5273

James Cockburn

James Gratrex

Patrick Merrild

Saad Nabeebaccus

Andries Waelkens