Dedicated Project of DESY and Helmholtz Association (SO-072)

Aim: enchance the interpretation of the measurements at the LHC through pinning down the fundamental QCD parameters and deeper insight into the proton structure.

Designed for the discovery of the Higgs boson and physics beyond the Standard Model, the LHC is a QCD machine operating in a new energy regime. The LHC experiments are confronted with unprecedented rates of events with multiple jets and vector bosons, as well as top quarks. The full discovery potential therefore depends on reliable predictions for signal and background processes. Measurements of various observables in different regions of phase space are required in order to extract complementary information on the fundamental parameters of the theory. Most involved observables are interconnected by their sensitivity to the proton structure, expressed via parton distribution functions (PDFs).

Members of the group belong to ATLAS and CMS groups at DESY and contribute significantly to development and support of XFitter and are involved in determination of QCD parameters and parton disitribution functions using DIS and proton collision data. This work is realized in close collaboration with theorists at DESY, University of Hamburg and Southern Methodist University in Dallas. The project group is the origin and the core of the PROSA collaboration.

The open-source program XFitter provides the basis for comparisons of different theoretical approaches and can be used for direct tests of the impact of new experimental data in the QCD analyses through coherent treatment of the data and theory calculations. Originally developed by the H1 and ZEUS collaborations and used for determination of HERAPDF sets, XFitter has been extended to the LHC experiments and to the implementation of different phenomenological approaches.

DiffTop is the Fortran-based package which allows the user to calculate the differential and total cross section for heavy-quark pair production at hadron colliders in One-particle inclusive (1PI) kinematics. The cross sections are calculated in perturbative QCD at approximate next-to-next-to-leading order (approx.NNLO) by using methods of threshold resummation beyond the leading logarithmic accuracy.

Dr. Katerina Lipka |
Principle Investigator, global QCD analysis, heavy-quark physics at HERA and LHC, XFitter/Difftop, PROSA executive Contact, Activities, Further Projects |

Dr. Voica Radescu
currently University of Heidelberg |
global QCD analysis, XFitter convenor, ATLAS PDF Forum convenor Collaboations: ATLAS and H1 Experiments, HERA Combination, XFitter, PROSA |

Dr. Pavel Starovoitov
DESY Hamburg |
jet physics at the LHC, ATLAS PDF Forum convenor Collaboations: ATLAS Experiment, XFitter, APPLGRID, PROSA |

Dr. Sebastian Naumann-Emme
currently teaching in Gymnasium, Hamburg |
Determination of top-quark mass and strong coupling, Convenor of CMS TOP mass group, XFitter interface to top-quark pair production Collaboations: CMS Experiment, XFitter, PROSA |

Dr. Marco Guzzi
currently University of Manchester |
global QCD analysis, nucleon structure phenomenology, XFitter S-ACOT-Chi scheme, Calculation of differential top-pair distributions at approximate NNLO Collaboations: CTEQ, CMS Experiment, DIFFTOP, XFitter, PROSA |

Dr. Andrea Vargas
DESY Hamburg |
QCD analysis of W and Z production at the LHC Collaboations: CMS Experiment, PROSA |

Jan Kieseler
DESY Hamburg |
Top-quark physics at the LHC, Measurements of top-quark pair and Z-boson production, alternative methods of measurement of top-quark pole mass Monte-Carlo production contact person for CMS TOP PAG Collaboations: CMS Experiment |

Dr. Oleksandr Zenaiev
DESY Hamburg |
Heavy quark physics at HERA, QCD analysis of HERA and LHCb data Collaboations: ZEUS Experiment, PROSA |