Projects / Programmes source: ARIS

Synergies between precision measurements and LHC discoveries

Research activity

Code Science Field Subfield
1.02.02  Natural sciences and mathematics  Physics  Theoretical physics 

Code Science Field
P210  Natural sciences and mathematics  Elementary particle physics, quantum field theory 

Code Science Field
1.03  Natural Sciences  Physical sciences 
high energy physics at hadron colliders, fermion flavor physics, top quark physics, electroweak symmetry breaking and the Higgs boson, generation of visible and dark matter in the early universe
Evaluation (rules)
source: COBISS
Researchers (1)
no. Code Name and surname Research area Role Period No. of publicationsNo. of publications
1.  24264  PhD Jernej Fesel Kamenik  Physics  Head  2011 - 2013  277 
Organisations (1)
no. Code Research organisation City Registration number No. of publicationsNo. of publications
1.  0106  Jožef Stefan Institute  Ljubljana  5051606000  91,044 
In the proposed project, we will focus on the interplay between the production and measurement of new particles at high energy hadron colliders on one hand, and the measurements of electroweak observables, quark, lepton flavour and CP violation at lower energies. We will address the following questions: - In which cases and under what assumptions can we use an effective theory description of the various mechanisms of unitarizing the electroweak theory as well as visible and dark cosmological matter generation while at the same time account for the bounds coming from the electroweak observables, flavour and CP violation at lower energies? - How can we, in such scenarios, use precision measurements to constrain or predict processes of new particles, if they are discovered at higher energies? - Conversely, which detection channels at high energy particle colliders are the most promising for discovery of new phenomena or particles given the stringent limits coming from existing precision measurements at lower energies? In the case that new particles are discovered at the LHC or complementary signals are detected in the processes of flavour or CP violation at the s.c. super-flavour factory, a key and difficult task will be to recognize models of new physics, which would explain the new signals, while at the same time being consistent with all other existing measurements. The results of this project would be instrumental in such an effort, as we would expose generic scenarios, common to many concrete new physics models, with the possibility to constrain or rule them out completely. Existing studies in the field can be roughly divided in two categories: (1) Analyses of concrete new physics models from the aspects of low energy measurements as well as high energy production of new particles; (2) Model-independent analyses using effective theory methods, focusing on low-energy aspects of new physics in the areas of flavour and CP violation, or contributions to electroweak observables, without immediate predictions for processes at high energy colliders. On the contrary, in the proposed project, we will consider several generic scenarios, which are, in the approximation valid at LHC energies, common to many explicit models of new physics, while at the same time allowing for a more complete study of the relevant aspects both at low energies as well as at high-energy colliders. We plan to explore the possible interplay between both aspects for the various possible mechanisms of theory unitarization as well as flavor and dark matter generation. In addition we will consider how precision measurements at low energies constrain the discoveries of new particles at high-energy colliders. In our investigation we will apply effective field theory methods, such as the spurion analysis, which allows for a consistent treatment of effective theories only partly respecting certain symmetries. The method has proven effective in the analysis of minimally flavour violating theories, while we plan to generalize it to electroweak analysis. We will also employ the expansion of theories with spontaneous chiral symmetry breaking. This approach, originating from studies of low energy pion and kaon processes, has in the recent years been established also in studies of effective electroweak symmetry breaking, which we shall also explore in this project.
Significance for science
The new results from the LHC (in particular the discovery of the Higgs boson) have fundamentally deepened our understanding of the basic laws of physics governing processes at the highest energies attainable in current experiments. At the same time, several recent measurements of rare processes in flavor physics, taking place at lower energies, are not in good agreement standard model predictions. The results of the the completed project, combining in a novel way the measurements in both types of experiments, has already received a relatively high impact in the scientific literature. At the same time, the obtained results opened new avenues of experimental measurements both at the LHC as well as in low energy precision experiments. Both achievements will in the long run contribute to our understanding of the fundamental puzzle of quark and lepton flavors.
Significance for the country
The completed research represents an important bridge between the studies of low energy measurements of flavour and CP violation, which were already well established in Slovenia, and hadronic physics at high energies, which has until recently not been studied theoretically in Slovenia at all, while becoming increasingly important world-wide. The results of the completed project placed Slovenia prominently on the map of theoretical high energy collider physics. This has been reflected also through the establishing of new and the strengthening of existing successful collaborations with other centers of theoretical high energy physics abroad (e.g. CERN, Harvard Univ., LBNL, INFN, CNRS, DESY, ICTP, T.U. Munich, Max Planck Inst., Univ. Valencia, Univ. Barcelona, Univ. Cincinnati, Weizmann inst.), which will enable new development and knowledge acquisition opportunities also in future.
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