Particle physicists using the CSCS supercomputer ‘Piz Daint’ have determined the scalar quark content of the proton – a vital step in the discovery of dark matter.
A research team from Cyprus, Germany and Italy led by Constantia Alexandrou of Cyprus Institute’s Computation-based Science and Technology Research Center (CaSToRC) and the Physics Department of the University of Cyprus in Nicosia, has calculated the scalar quark content of the proton using quantum chromodynamics (QCD).
The researchers expect that their calculations will help to further understanding into the nature and presence of dark matter as the scalar quark content of a nucleon must be understood to determine any potential interactions with scalar particles such as the Higgs boson.
In an article published on the CSCS website, Constantia Alexandrou stated: ‘If we are to interpret experimental results as direct evidence for dark matter, then it is essential to know the numeric value we determined for the condensates and hence the exact proportion of scalar quark content in the nucleon, in particular, what are known as strange quarks.’
Alexandrou and her colleagues at the CaSToRC are focusing their research efforts on quantum chromodynamics (QCD), a field which theoretically describes ‘strong interactions’, a fundamental force characterising the interactions between quarks and gluons, the building blocks of larger particles such as protons and neutrons.
The CaSToRC team’s latest research is based on lattice QCD; Lattice QCD is a lattice gauge theory formulated on a grid or lattice of points in space and time. Although incredibly computationally intensive, lattice QCD provides a non-perturbative approach to solving the quantum chromodynamics (QCD) theory of quarks and gluons.
The project entitled ‘computationally-intensive, high impact research on novel outstanding science (CHRONOS)’ was particularly suited to the CSCS cluster because of simulations are very intensive but also because the algorithms are limited by memory bandwidth.
Piz Daint is based on a Cray XC30, featuring 5272 compute nodes Intel Xeon E5-2670 CPU at 2.60GHz, and Nvidia Tesla K20X GPUs. Piz Daint is scheduled for an upgrade later this year which will double the peak performance of the supercomputer and introduce the latest Pascal based Nvidia GPUs.
The results of this project will now be used in further research to investigate and identify evidence of an interaction between the Higgs boson and the scalar condensate inside the nucleon. Ultimately, the work was done by Alexandrou and her team on the Swiss supercomputer ‘Piz Daint’ is helping physicists to detect and research dark matter.
