Measurements and QCD analysis of the LHC processes (Run II) / Phenomenology :
Novel phenomenological analysis with the aim of simultaneous determination of the gluon distribution, top-quark mass and strong coupling constant by using the jet, W-boson and top-quark production cross sections measured in proton-(anti) proton collisions.
Searches for New Physics in a global SM/BSM analysis of various physics processes by using XFitter.
Depending on your education stage, these research topics are available for Masters, Ph.D. or Postdocs in experimental or theoretical high energy physics.
As experimentalist, you deal with production of jets, top-quark pairs and electroweak bosons at unprecedented energies and might choose your most favourite process to contribute to its measurement at the LHC in Run II within CMS collaboration. Alternatively - in case you would rather like to contribute to detector or software development but would still like to get an overview of the LHC measurements and their interpretation, you might jump in for a short time and perform a QCD analysis with available - but not yet used - LHC data and contribute significantly to an ongoing publication.
If you are a phenomenologist interested in the determination of PDFs, strong coupling constant and heavy quark masses, development of the QCD analysis tools or related higher-order calculations, you are welcome to join our team in association to CMS and address the topics of your interest, profiting from our close collaboration to the world-leading QCD phenomenology groups of DESY, University of Hamburg and Southern Methodist University of Dallas, Texas.
You are working in a experimental-theory expert team
Hardly any other topic gives you a broad insight in such a diversity of processes at the LHC and their sensitivity to different aspects of the fundamental particle physics. You are working in a team of experts in PDF determination who help you to get into the topic and available tools very fast. You can use the exchange program between Dallas and Hamburg and spend up to 6 months a year in the SMU, working closely with our colleagues from the CTEQ collaboration (Center for Theoretical and Experimental QCD). Stays at CERN are wished and possible.
Your Main Task: Enhancing LHC discovery potential.
Under "interpretation of the LHC measurements" we usually understand confronting the experimental data to theory predictions. Through such comparisons, the fundamental parameters of the Standard Model are determined or the signs of new physics can be observed. Precision of such interpretation defines the discovery potential. Therefore, the main focus for the LHC-related program in particle physics for the next 5 years is precision. Accuracy of both, experimental data and of the theory predictions will play the key role in the interpretation of the new LHC results at unprecedented energies of 13 and 17 TeV (LHC Run II).
With increased experimental precision at the LHC for Run II and with decreased theoretical uncertainties due to available calculations at higher and higher order, the remaining dominant uncertainty, limiting the LHC discovery potential is understanding of the proton structure , since most of the processes in proton-proton collisions at the LHC are quark- or gluon-initiated.
The proton structure has been studied in earlier dedicated experiments, like H1 and ZEUS at HERA accelerator at DESY, however the precision of the parton distribution functions (PDFs) obtained from the HERA data only is not essential for significant theory predictions for the full LHC kinematics. The solution of this problem is using the precise measurements at the LHC to obtain the proton PDFs in addition to the measurements of HERA and therethrough improving the PDF precision in the kinematic ranges of interest and enhancing the LHC discovery potential.
This is our main goal and what we offer you to join our team for.