Precise determination of the low energy constants of the chiral Lagrangian using the epsilon-regime of chiral perturbation theory

• Applicant: Professor Dr. Andrea Shindler
• Subject Area: Nuclear and Elementary Particle Physics, Quantum Mechanics, Relativity, Fields
• Term: from 2012 to 2015
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 221381267

One of the main challenges within the Standard Model is to understand how an intrinsically simple theory like QCD can give rise to the amazing structures observed at low energy. A basis for a coherent scheme that would allow us, in principle, to address these problems in QCD, is to combine Lattice QCD simulations performed at different values of the quark masses with chiral perturbation theory (χPT). This effective theory is parametrized in terms of couplings, low energy constants (LECs), which contain all the non-perturbative information of the QCD dynamics. The LECs are of key interest because they provide the unique link between the highly non-trivial dynamics of QCD and the light quark mass dependence of a plethora of physical observables. There is still room for improvements in the determination of LECs. The main goal of this project is to investigate different observables and power countings within χPT for a precise determination of the LECS. Given the universality of the LECs this allows to further constrain their value and given the generality of the approach it can be used for all the LECs which are poorly determined with standard computations.

• DFG Programme: Research Grants