Projects / Programmes source: ARIS

The Theory of Nuclei, Elementary Particles and Fields

Research activity

Code Science Field Subfield
1.02.00  Natural sciences and mathematics  Physics   
1.07.00  Natural sciences and mathematics  Computer intensive methods and applications   

Code Science Field
P2   Natural sciences and mathematics  P2  

Code Science Field
1.03  Natural Sciences  Physical sciences 
Quark models, excited barion states, weak decays, B and D mesons, lattice QCD, standard model, infrared singularities, p-branes, grand unified theories, monopoles, proton decay, three-body problem, computational physics, ionization
Evaluation (rules)
source: COBISS
Researchers (20)
no. Code Name and surname Research area Role Period No. of publicationsNo. of publications
1.  10561  PhD Borut Bajc  Physics  Researcher  2009 - 2014  264 
2.  30870  PhD Jure Drobnak  Physics  Researcher  2009 - 2014  15 
3.  14130  PhD Svjetlana Fajfer  Physics  Head  2009 - 2014  393 
4.  37468  PhD Darius A. Faroughy Carias  Physics  Junior researcher  2014  21 
5.  24264  PhD Jernej Fesel Kamenik  Physics  Researcher  2009 - 2014  277 
6.  02579  PhD Bojan Golli  Physics  Researcher  2009 - 2014  278 
7.  34436  PhD Admir Greljo  Physics  Researcher  2011 - 2014  14 
8.  26228  Nevenka Hauschild    Technical associate  2009 
9.  35593  PhD Julio Julio  Physics  Researcher  2012 - 2013 
10.  28803  Martina Knavs    Technical associate  2014  32 
11.  26459  PhD Nejc Košnik  Physics  Researcher  2009 - 2014  79 
12.  09087  PhD Rajmund Krivec  Physics  Researcher  2009 - 2014  106 
13.  34446  PhD Luka Leskovec  Physics  Junior researcher  2011 - 2014  58 
14.  32156  PhD Timon Mede  Energy engineering  Junior researcher  2009 - 2013  29 
15.  25656  PhD Miha Nemevšek  Physics  Researcher  2009 - 2014  158 
16.  33430  PhD Ivan Nišandžić  Physics  Researcher  2011 - 2014 
17.  01107  PhD Matej Pavšič  Physics  Researcher  2009 - 2012  153 
18.  15643  PhD Saša Prelovšek Komelj  Physics  Researcher  2009 - 2014  221 
19.  33269  PhD Vasja Susič  Physics  Researcher  2010 - 2014  10 
20.  19163  PhD Jure Zupan  Physics  Researcher  2009 - 2014  222 
Organisations (2)
no. Code Research organisation City Registration number No. of publicationsNo. of publications
1.  0106  Jožef Stefan Institute  Ljubljana  5051606000  91,059 
2.  1554  University of Ljubljana, Faculty of Mathematics and Physics  Ljubljana  1627007  34,275 
We shall investigate the properties of hadrons in chiral quark models with emphasis on the calculation of pion weak- and electroproduction amplitudes to be measured in the planned experiments in Mainz and JLab. Our plan is to investigate the decay mechanism in nonleptonic weak decays of heavy mesons, the CP violating quantities in these decays and we question the possible signals of new physics in rare decays of heavy mesons. We intend to study the hadron properties and hadron decays using the nonperturbative quantum chromodynamics on the lattice. We plan to explore whether (i) quantum Yang-Mills field theories exist in axial-type gauges and (ii) have a mass gap and confine quarks, availing ourselves of the analogy of problem (i) with the problem of singularity-free variational formulation of quantum scattering and, concerning (ii), of gravity/gauge dualities in elucidating the role of incomplete Bloch-Nordsieck cancellation of infrared singularities in perturbatively calculated cross-sections. Part of our research will be devoted to studying high energy physics beyond the standard model, the supersymmetric grand unification, fermion masses and mixings, magnetic monopoles, proton decay and cosmology. We will investigate the theory of relativity and quantum field theory in flat and curved Clifford space, which is a straightforward, but non trivial, extension of spacetime, with the aim of unifying the fundamental interactions and resolving some important problems, for instance, of dark matter, dark energy and the cosmological constant. Corrections to high-energy single- and double-ionization of two-electron ions will be studied, for which purpose we shall calculate locally correct, high-precision three-body wave functions. We shall further improve on and extend the applicability of the recently developed quazilinearization method.
Significance for science
Because of the non-perturbative nature of QCD in the low-energy region the investigations in the framework of effective quark models are relevant to understand the structure of nucleon as well as the hadron processes. The calculations of meson electro-production amplitudes are useful to explain data and to design new experiments at JLab and Mainz The proposed simulations on the lattice will give an indication whether some of the observed resonances are the conventional q-barq s tates or perhaps the exotic tetraquark states. The comparison of the lattice results with the experimental observations will tell us how well one handles nonperturbative regime of QCD theoretically. Simulations will lead to a better understanding of hadron structure. We expect that the results of our work will have impact on the particle physics field in the following ways: i) the types of searches discussed will allow for model independent check that no on-shell resonances have been missed in direct searches and ii) will allow for searches of NP effects beyond the kinematical reach of LHC paving the path for the future of particle physics. The flavor violation research at high pT will directly address modifications of expected New Physics signals at LHC. Most of the signal simulations at ATLAS and CMS assume Minimal Flavor Violation and even that in its most naive version (for instance taking degenerate soft susy breaking squark mass matrices). The proposed project can have a significant impact in this respect, as a large violation of flavor symmetry can result in the appearance of a multitude of edges in the mass distributions (which may be or may not be easy to spot), since different resonances can now decay using common decay chain and can potentially lead to difficulties with mass spectrum measurements. Large flavor violations are still allowed, since the low energy experiments are bounding only transitions of certain chirality (in the MSSM language these bound only squark mass insertions of LL and LR type, but not of the RR type). As a rule of thumb we thus expect large enough flavor violation effects in the general case to be observed at the LHC. Theoretical research in the field of elementary particles is especially important in this particular moment, because of the planned opening of the Large Hadron Collider. The knowledge and understanding of the physics beyond the standard model will help in the interpretation of possible signals, allowing to test the predictions of different models Among them it is particularly predictive the nonsupersymmetric SU(5) model that we first proposed. LHC will be able to scan in the following years a good portion of the model parameter space. Ionization problems studied are related to experiments on recent synchrotrons (J. Ullrich et al., "Recoil-ion momentum spectroscopy", J. Phys. B: At. Mol. Opt. Phys. 30, 2917-2974 (1997). Among the interesting recently discovered effects is the "quasi-free" mechanism, whose serious study was initiated by our group (Phys. Rev A64, 012713 (2001)).
Significance for the country
The theory of the electroweak and strong interactions of the basic elementary objects is known as the standard model. Contemporary world is very interested to learn more about the structure and nature of fundamental interactions and it financially supports such a studies. In the cultural development of Slovenia it is very important to have creative scientists who actively contribute in the development of this picture. The scientific community of the whole world will attribute Slovenia such a cultural level which Slovenian scientists create in their communication. On the social level it is important to work on the problems of elementary particle physics, due to the influence on our perception of the outside world. Within Slovenian frame it is important to have a theoretical group in this field which can bring in Slovenian research and cultural space new achievements in this field. This is very important on the university level, which is supposed to include recent scientific results in the current teaching process. Theoretical studies of our group are important for the Slovenian experimental physicists in this area, making the predictions relevant for their studies, counseling and in interpreting new experimental results. For Slovenia it is important to be active also in lattice QCD, since this ab-initio method is providing ever more reliable results due to the improvements of computer technology and due to the developments of the lattice methods involved. The theoretical and experimental high-energy community in Slovenia will benefit from having local experts in this field, who can provide understanding and interpretation of the results from most recent lattice simulations. The proposed research will have an impact on the socio-economic development of Slovenia in the following ways: the proposed research is the first theoretical research of hadronic physics at high energies in Slovenia. From the collaboration with other scientists in EU and USA we expect the transfer of knowledge to Slovenia. The continuous interaction with partners from abroad, publishing in international journals and active participation in international conferences contribute to the promotion of Slovenia. A good knowledge of the latest results and theories is necessary in teaching and mutual help with experimental physicists. While developing the CFHHM and QLM methods we also develop the corresponding program code. We try to maintain a high level of know-how in large code optimization, where the coding methods may differ substantially from those taught at school, the latter stressing simplicity and certain elegance to the code. For example, large programs require data locality in order to speed up data transfer between memory and the CPU, usually necessitating a completely different code topology. Another example is the nontrivial decision whether to make code parallelism coarse or fine grained, i.e., whether to apply the MPI library and work on weakly connected CPUs or else apply openmp and work on an SMP (shared memory) machine. Such know-how may result in halved equipment budgetary requirements, and also builds a tool repository useful for application projects. In this way we realized a flight model able to simulate certain types of military aircraft, using knowledge based on QLM and optimization of several CPU-intensive codes, resulting in code able to generate up to 250 states per second in a nonsymmetrical configuration.
Most important scientific results Annual report 2009, 2010, 2011, 2012, 2013, final report, complete report on dLib.si
Most important socioeconomically and culturally relevant results Annual report 2009, 2010, 2011, 2012, 2013, final report, complete report on dLib.si
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