QCD Simulations with Light Quark Flavors
|Scientific Discipline||Lattice Field Theory|
|Principal Investigator(s)||Dr. Karl Jansen|
|Leading Institution||John von Neumann Institute for Computing, Zeuthen, Germany|
|DEISA Home Site||FZJ|
Certainly, Quantum Chromodynamics (QCD) is our present best model of the strong interaction of particle physics. However, it is far from being demonstrated that it indeed describes all aspects of the strong forces. In particular, non-perturbative phenomena such as the confinement of quarks, the symmetry breaking pattern of the interchange of massless left- and right-handed quarks, the violation of time-reversal symmetry and surprisingly large differences in the cross-section of very similar decay processes of the K-meson are completely un-resolved problems. To address such questions one has to resort to non-perturbative methods, in particular to large scale numerical simulations in a discretized version of QCD, i.e. lattice QCD.
The aim of this DEISA application project is to perform first realistic simulations of lattice QCD. This means to use dynamical fermions taking the strange quark mass into account in the simulation and to run at light quark masses, as close as possible to the 'physical point', where the pion mass assumes its experimentally measured value. In addition, the volume should be sufficiently large, corresponding to a box length of at least 2 fm. This demanding setup can be realized by using a new formulation of lattice QCD, so-called maximally twisted mass fermions, as we have as a proof of principle in our preparatory work.
The physics problems we want to address in this project are the hadron spectrum, decay constants and matrix elements relevant for moments of parton distribution functions. Moreover, we would like to study the decay of the rho-meson, the breaking of the confining string, B(K) and the photon vacuum polarization tensor relevant for the value of (g-2)μ. All these are questions that are deeply linked to experimental efforts worldwide to understand better and test the validity of our standard model of particle interactions, eventually leading to hints of new physics beyond our present standard model of elementary particle physics.
We have collected a number of institutes in Germany (Zeuthen, Munster, Hamburg), the United Kingdom (Liverpool) and Italy (Rome) to build up a European collaboration which might be even enlarged by incorporating additional groups in Italy (Milan).