# Applications from Elementary Particle Physics

Here we present a choice of impressive projects from elementary particle physics which have been carried out on GCS supercomputers.

## Petascale Computations for Atomic and Molecular Collisions

Research efforts of an international group of scientists from Germany, the UK, and the US focus on the development of computational methods to obtain quantities that can be measured from the equations of motion that arise for atoms and molecules interacting with electrons or light within a fully quantum description.
**More: Petascale Computations for Atomic and Molecular Collisions …**

## Chiral Symmetry and Topological Properties in Lattice QCD With Wilson Twisted Mass Quarks

Quantum Chromodynamics (QCD) represents the nowadays widely accepted theory describing the interaction of quarks and gluons. QCD is expected to show a very similar phenomenon like the magnetisation of a ferromagnet, just that the magnetisation is called chiral condensate and the equivalent of the external magnetic field is a finite quark mass. Theoretical physicists of the Deutsches Elektronen-Synchrotron (DESY) and the Rheinische Friedrich-Wilhelms-Universität Bonn evaluated for the first time the chiral condensate using lattice QCD with dynamical up, down, strange and charm quarks and, therefore, confirm the expectation.
**More: Chiral Symmetry and Topological Properties in Lattice QCD With Wilson Twisted Mass Quarks …**

## Extreme Plasma Acceleration: From the Laboratory to Astrophysics

A team of scientists investigated novel positron and ion acceleration schemes towards a future plasma based linear collider and medical applications, novel magnetic field generation mechanisms relevant in astrophysical scenarios, and laser-plasma interaction studies for fusion applications.
**More: Extreme Plasma Acceleration: From the Laboratory to Astrophysics …**

## QCDpQED--QCD Plus QED and the Stability of Matter

The mass of our visible universe is to a very large part provided by the strong nuclear interaction between elementary quarks, as described by the theory of quantum chromodynamics (QCD). In order to understand more deeply not only the origin of the mass of the visible universe but also its composition, tiny differences in the particle masses, especially those of protons and neutrons, are essential.
**More: QCDpQED--QCD Plus QED and the Stability of Matter …**

## Baryon Structure Using Dynamical QCD Simulations With Physical Values of the Light, Strange and Charm Quark Masses

A team of international scientists, cooperating under the name European Twisted Mass Collaboration (ETMC), uses supercomputer JUQUEEN of JSC in their efforts to understand the properties of elementary particles such as the proton, which forms most of the ordinary matter around us.
**More: Baryon Structure Using Dynamical QCD Simulations With Physical Values of the Light, Strange and Charm Quark Masses …**

## Excited State Artefacts in Calculations of Hadron 3-Point Functions

Lattice QCD (Quantum Chromodynamics) allows to calculate properties of states which are composed of quarks and gluons, called hadrons. The most important hadrons are proton and neutron, i.e. the nucleons. To obtain this information from Lattice QCD one has to calculate what is called “3-point- functions”. With large computer resources provided such as by SuperMUC scientists were able to do this much more precisely. Furthermore, physical quark masses could be simulated rather than scientists having to rely on extrapolations from simulations with larger than physical quark masses.
**More: Excited State Artefacts in Calculations of Hadron 3-Point Functions …**

## Kaon Semi-Leptonic Form Factor

The CKM-matrix (Cabibbo-Kobayashi-Maskawa) describes the mixing between the mass eigenstates and electro-weak eigenstates of the different quark flavors in the Standard Model of Particle Physics. Scientists leverage the computing power of HPC system SuperMUC for tests of the unitarity of the CKM matrix and therefore also probe the Standard Model of Particle Physics.
**More: Kaon Semi-Leptonic Form Factor …**

## Nucleon and Meson Matrix Elements Close to the Physical Point

The validity of Quantum Field Theory (QFT) is proven beyond any reasonable doubt, but at the same time it is clear that the Standard Model is incomplete in many respects. Also, there are many aspects of the Standard Model, in particular of the QCD (Quantum Chromodynamics) sector, which are not yet understood. It is hoped that the combination of dedicated new experiments and Lattice QFT will allow to improve the understanding of these aspects.
**More: Nucleon and Meson Matrix Elements Close to the Physical Point …**

## Next Generation Lattice QCD Simulations of the First Two Quark Generations at the Physical Point

An international team of scientists leverages the computing power of supercomputers for a very ambitious project which is embedded in the area of elementary particle interactions and in particular the strong interaction of quarks and gluons which is described theoretically by quantum chromodynamics (QCD), a relativistic quantum field theory.
**More: Next Generation Lattice QCD Simulations of the First Two Quark Generations at the Physical Point …**

## Controlled Electron-Beam Injection into Plasma Waves for Tailored Betatron-Radiation Generation

Researchers study few-femtosecond, phase-space-tailored electron bunches inside plasma wakefields. These bunches are generated by means of external injection of conventionally accelerated electron beams or by controlled, plasma-internal injection schemes.
**More: Controlled Electron-Beam Injection into Plasma Waves for Tailored Betatron-Radiation Generation …**

## First Lattice QCD Study of B-physics With Four Flavors of Dynamical Quarks

Researchers from the three universities of Rome, the universities of Valencia, Paris XI, Groningen, Bonn, and Berlin have formed a team to carry out an extensive study of the physics of mesons containing a beauty quark. The results of this study will allow to address issues relevant for the phenomenology of the so-called flavor sector of the Standard Model and its possible extensions to New Physics.
**More: First Lattice QCD Study of B-physics With Four Flavors of Dynamical Quarks …**

## The Spectrum of Supersymmetric Yang-Mills Theory

In a joint project of scientists of the Universitiy of Münster, the University of Frankfurt, and of DESY, Hamburg, researchers investigate the properties of the

N = 1 supersymmetric Yang-Mills theory, a theory which has supersymmetry and is part of many models for the physics beyond the Standard Model.
**More: The Spectrum of Supersymmetric Yang-Mills Theory …**

## Quantum Monte Carlo Simulation of Hydrogen at High Pressure

An international team of physicists used GCS supercomputer Hermit to elucidate important aspects of the hydrogen phase diagram related to the pressure-induced molecular dissociation and metallization and to improve the treatment of electronic correlation by developing algorithms based on Quantum Monte Carlo (QMC) methods.
**More: Quantum Monte Carlo Simulation of Hydrogen at High Pressure …**

## A lattice QCD Calculation of the Leading Order Hadronic corrections to g − 2 of the Muon

Researchers from Wuppertal and Marseilles are using lattice quantum chromodynamics (QCD) to calculate contributions of the strong force to the anomalous magnetic moment of the muon, a heavier cousin of the electron.
**More: A lattice QCD Calculation of the Leading Order Hadronic corrections to g − 2 of the Muon …**

## Heavy Ion Phenomenology Form Lattice Simulations

A team of physicists used JSC supercomputer JUQUEEN to study the energy density, entropy, specific heat and pressure of quark gluon plasma, starting from a high temperature at its creation to a low temperature where the plasma actually freezes. Their goal: to identify the plasma's break-up point, i. e. the point when the plasma freezes and its matter is transformed into subatomic particles.
**More: Heavy Ion Phenomenology Form Lattice Simulations …**

## 2+1+1 Lattice QCD Calculations With HEX Smeared Clover Fermions

Supercomputer resources of GCS enable physicists to solve the equations of QCD on a large enough and simultaneously fine enough lattice to accurately compute the effects of the charm quark and predict the masses of short-lived particles it is contained in.
**More: 2+1+1 Lattice QCD Calculations With HEX Smeared Clover Fermions …**

## Fluctuations of Conserved Charges in the Quark Gluon Plasma

Leveraging the vast computing power of HPC system JUQUEEN of JSC, an international team of physicists aims on a model independent determination of the freeze-out temperature and density of Quark Gluon Plasma (QGP), based on the fundamental equations of the theory of strongly interacting matter, Quantum Chromodynamics (QCD).
**More: Fluctuations of Conserved Charges in the Quark Gluon Plasma …**

## Lattice QCD with Wilson Quarks at zero and non-zero Temperature

A team of researchers, led by Prof. Hartmut Wittig of the University of Mainz, investigates the many facets of QCD in the low-energy regime using GCS supercomputing resources.
**More: Lattice QCD with Wilson Quarks at zero and non-zero Temperature …**

## Precision Computation of f_{K}/f_{π} from Staggered 2+1+1 Flavor Simulations

A a team of scientists of the University of Wuppertal under leadership of Dr. Stephan Duerr uses GCS supercomputers for precision tests of the first-row unitarity relation of the Cabibbo-Kobayashi-Maskawa (CKM) matrix.
**More: Precision Computation of fK/fπ from Staggered 2+1+1 Flavor Simulations …**

## Flavor Physics of Up, Down and Strange Quarks from Simulations of Dynamical QCD + QED

In the a. m. project, an international team of scientists under leadership of particle physicist Prof. Dr. Gerrit Schierholz from DESY (Deutsches Elektronen-Synchrotron) run a fully dynamical simulation of QCD + QED on GCS supercomputers.
**More: Flavor Physics of Up, Down and Strange Quarks from Simulations of Dynamical QCD + QED …**

## Matter-Antimatter Asymmetry

The dominance of matter over antimatter in our universe is one of the unsolved riddles of present day physics. During the early phases of our universe, matter must have been produced predominantly over antimatter, but the only such process we currently know only affects quarks, the fundamental constituents of the atomic nucleus, and does not provide enough matter dominance.
**More: Matter-Antimatter Asymmetry …**

## Finite Temperature Lattice QCD with Wilson Quarks

Theoretical investigation of matter at extreme high temperatures and densities has a huge importance since this kind of matter is produced in heavy-ion collision experiments.
**More: Finite Temperature Lattice QCD with Wilson Quarks …**

## Pseudoscalar Decay Constants at the Physical Mass Point

With the help of supercomputing, scientists from the University of Wuppertal tackle a key component of Elementary Particle Physics: The fundamental forces of nature.
**More: Pseudoscalar Decay Constants at the Physical Mass Point …**

## The Synthesis of the Elements, in Particular Carbon

Life on Earth is based on carbon that was generated in stars. A special role in the synthesis of carbon is played by a particular excited state of carbon, the socalled Hoyle state.
**More: The Synthesis of the Elements, in Particular Carbon …**