# 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.

## Nucleon Structure Using Lattice QCD Simulation with Physical Pion Mass

Scientists are leveraging HPC system SuperMUC for state-of-the-art lattice Quantum Chromodynamics (QCD) simulations. Using these Tier-0 computational resources, the team of international researchers has pioneered the calculation of key observables that characterize the structure of protons and neutrons, collectively referred to as nucleons.

**Principal Investigator:** Constantia Alexandrou, University of Cyprus and The Cyprus Institute (Cyprus)

**HPC Platform:** SuperMUC of LRZ - **Date published:** April 2016

**More: Nucleon Structure Using Lattice QCD Simulation with Physical Pion Mass …**

## Pair-Dominated Plasmas and Radiation in Ultra Intense Fields

Leveraging the petascale computing power of SuperMUC, an international team of researchers performed 2D/3D simulations of laser absorption in dense electron-positron plasmas self-consistently created via electromagnetic cascades. Their numerical findings provide a set of laser parameters to optimize the conversion of optical photons into pairs and gamma rays allowing to mimic extreme astrophysical scenarios and their radiation signatures.

**Principal Investigator:** Thomas Grismayer, GoLP/IPFN, Instituto Superior Técnico, Lisboa (Portugal)

**HPC Platform:** SuperMUC of LRZ - **Date published:** March 2016

**More: Pair-Dominated Plasmas and Radiation in Ultra Intense Fields …**

## Lattice QCD + QED: Towards a Quantitative Understanding of the Stability of Matter

Leveraging the petascale computing power of HPC system JUQUEEN, scientists at Deutsches Elektronen-Synchrotron (DESY) in Hamburg, Germany, included for the first time both Quantum Chromodynamics (QCD) and Quantum Electrodynamics (QED) in a nonperturbative calculation. This allowed the physicists to predict isospin breaking effects in the meson, baryon and quark sectors from first principles, and in particular the n - p mass difference.

**Principal Investigator: **Gerrit Schierholz, DESY Hamburg (Germany)

**HPC-Platform: **JUQUEEN of JSC – **Date published:** February 2016

**More: Lattice QCD + QED: Towards a Quantitative Understanding of the Stability of Matter …**

## Full Scale Modelling of the Proton Driven Plasma Wakefield Accelerator

Leveraging high performance computing system SuperMUC, an international team of researchers performed 3D simulations of scenarios relevant to The Proton Driven Plasma Wakefield Acceleration Experiment framed by AWAKE, an accelerator R&D project based at CERN. Their numerical findings provide a set of conditions for which the long proton bunches could propagate stably over arbitrarily long distances, and explore possible experimental configurations that could be relevant to investigate astrophysical scenarios in the lab.

**Principal Investigator:** Jorge Vieira, Instituto Superior Técnico, Lisboa (Portugal)

**HPC Platform:** SuperMUC of LRZ - **Date published:** February 2016

**More: Full Scale Modelling of the Proton Driven Plasma Wakefield Accelerator …**

## Exploring the Quark Mass Plane with Open Boundaries

An international team of researchers leveraged the computing power of supercomputer JUQUEEN in the context of a very large international effort in Lattice quantum chromodynamics (QCD). The project addressed important aspects of hadron physics for the very first time respectively with unprecedented accuracy, which would not have been possible without superior high performance computing (HPC) power.

**Principal Investigator:** Andreas Schäfer, Institut für Theoretische Physik, Universität Regensburg (Germany)

**HPC Platform:** JUQUEEN of JSC - **Date published:** January 2016

**More: Exploring the Quark Mass Plane with Open Boundaries …**

## Electron-Injection Techniques in Plasma-Wakefield Accelerators for Driving Free-Electron Lasers

Researchers from the Deutsches Elektronen-Synchrotron Hamburg (Germany) study and design electron-injection techniques in plasma-wakefield accelerators for the production of high-quality beams suitable for application as free-electron lasers. Since the physics involved in the process cannot be treated analytically in most of the cases of interest, particle-in-cell simulations are required which allow to calculate the response of the plasma electrons to the passage of charged beams and/or high-intensity lasers.

**Principal Investigators:** Jens Osterhoff and Alberto Martinez de la Ossa, Deutsches Elektronen-Synchrotron - DESY, Hamburg (Germany)

**HPC Platform:** JUQUEEN of JSC - **Date published:** January 2016

**More: Electron-Injection Techniques in Plasma-Wakefield Accelerators for Driving Free-Electron Lasers …**

## Gluonic Scale Setting With √t_{0} and w_{0}

Physicists at the University of Wuppertal harness the supercomputer power of the JSC HPC system JUQUEEN to carry out a computation of the gluonic scales √t_{0} and w_{0} in QCD with 2+1+1 dynamical quarks where each of them is taken at its respective physical mass.

**Principal Investigator:** Stephan Dürr, Institut für Theoretische Physik, FB-C, Universität Wuppertal (Germany)

**HPC Platform: **JUQUEEN of JSC - **Date published:** December 2015

**More: Gluonic Scale Setting With √t0 and w0 …**

## Precise Relation Between Quark Masses in Different Renormalization Schemes

Leveraging the HPC platform of the HLRS, an international team of researchers of the Karlsruhe Institute of Technology, the Deutsches Elektronen-Synchrotron (DESY), and the Moscow State University have computed a precise relation between heavy quark masses defined in the two most commonly used renormalization schemes, the minimal subtraction (MS) and on-shell scheme.

**Principal Investigator:** Matthias Steinhauser, Institut für Theoretische Teilchenphysik, Karlsruhe Institute of Technology/KIT (Germany)

**HPC Platform: **Hornet and Hermit of HLRS - **Date published:** September 2015

**More: Precise Relation Between Quark Masses in Different Renormalization Schemes …**

## Lattice QCD Investigations of Nuclear and Hadronic Properties

The typical scale of Quantum Chromodynamics (QCD) is on the level of GeV (giga electron volt), but QCD should also describe nuclear physics, with has a typical scale of MeV (mega electron volt). This three orders of magnitude difference is a precision challenge, which scientists now were able to tackle in the proton-neutron system.

**Principal Investigator:** Zoltán Fodor, Institut für Theoretische Physik, FB-C, Universität Wuppertal (Germany)

**HPC Platform:** JUQUEEN of JSC - **Date published:** March 2015

**More: Lattice QCD Investigations of Nuclear and Hadronic Properties …**

## Calculation of Tunneling Splittings of Vibrational Eigenstates of Malonaldehyde

Using the Heidelberg MCTDH package (Multi Configuration Time Dependent Hartree), Heidelberg based scientists investigated the spectral properties of malonaldehyde. The HPC resources of HLRS in Stuttgart served as computing platform for this project.

**Principal Investigator:** Hans-Dieter Meyer, Institute of Physical Chemistry, Universität Heidelberg (Germany)

**HPC Platform: **Hermit of HLRS - **Date published:** March 2015

**More: Calculation of Tunneling Splittings of Vibrational Eigenstates of Malonaldehyde …**

## Numerical Determination of the Phase Diagram of Nuclear Matter

Using GCS HPC system resources, scientists of the Institute for Theoretical Physics of the Goethe-Universität in Frankfurt/Germany are performing extensive simulations to theoretically predict the properties of the phase transition from nuclear matter to a quark gluon plasma state.

**Principal Investigator:** Owe Philipsen, Universität Frankfurt, ITP (Germany)

**HPC Platform:** JUQUEEN of JSC - **Date published:** February 2015

**More: Numerical Determination of the Phase Diagram of Nuclear Matter …**

## A Lattice QCD Calculation of Vector Meson Decay Constants

Leveraging the computing power of HPC system JUQUEEN of Jülich Supercomputing Centre, researchers from Bergische Universität Wuppertal (BUW) are using lattice quantumchromodynamics (QCD) to calculate vector meson decay constants f_{V} , where V represents a vector meson such as ρ, ω, φ, etc.

**Principal Investigator:** Eric B. Gregory, Institut für Theoretische Physik, FB-C, Universität Wuppertal (Germany)

**HPC Platform:** JUQUEEN of JSC - **Date published:** January 2015

**More: A Lattice QCD Calculation of Vector Meson Decay Constants …**

## 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.

**Principal Investigator:** Alfred Müller, Institut für Atom- und Molekühlphysik, Universität Giessen (Germany)

**HPC Platform:** Hermit of HLRS - **Date published:** November 2014

**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.

**Principal Investigator:** Carsten Urbach, Universität Bonn (Germany)

**HPC-Platform:** SuperMUC of LRZ - **Date published:** October 2014

**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.

**Principal Investigator:** Jorge Vieira, Instituto Superior Técnico, Universidade de Lisboa (Portugal)

**HPC Platform: **SuperMUC of LRZ - **Date published:** September 2014

**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.

**Principal Investigator:** Zoltán Fodor, Institut für Theoretische Physik, FB-C, Universität Wuppertal (Germany)

**HPC Platform:** JUQUEEN of JSC - **Date Published:** September 2014

**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.

**Principal Investigator:** Constantia Alexandrou, University of Cyprus (Cyprus)

**HPC Platform:** JUQUEEN of JSC - **Date published:** September 2014

**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.

**Principal Investigator:** Andreas Schäfer, Institut für Theoretische Physik, Universität Regensburg (Germany)

**HPC Platform: **SuperMUC of LRZ - **Date published:** July 2014

**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.

**Principal Investigator:** Enno E. Scholz, Institut für Theoretische Physik, Universität Regensburg (Germany)

**HPC Platform:** SuperMUC of LRZ - **Date published:** July 2014

**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.

**Principal Investigator:** Andreas Schäfer, Institut für Theoretische Physik, Universität Regensburg (Germany)

**HPC Platform:** SuperMUC of LRZ - **Date Published:** May 2014

**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.

**Principal Investigator:** Karl Jansen, Deutsches Elektronen-Synchrotron/DESY, Zeuthen (Germany)

**HPC Platforms:** SuperMUC (LRZ) and JUQUEEN (JSC) - **Date pub.:** May 2014

**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.

**Principal Investigator:** Jens Osterhoff, Deutsches Elektronen-Synchrotron/DESY, Hamburg (Germany)

**HPC Platform:** JUQUEEN of JSC - **Date published:** April 2014

**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.

**Principal Investigator:** Silvano Simula, Istituto Nazionale di Fisica Nucleare (INFN) - Sezione Roma Tre (Italy)

**HPC Platform:** JUGENE/JUQUEEN of JSC - ** Date published:** April 2014

**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.

**Principal Investigator:** Gernot Münster, Institut für Theoretische Physik, FB-C, Universität Münster (Germany)

**HPC Platform:** JUQUEEN of JSC - **Date published:** March 2014

**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.

**Principal Investigator:** Carlo Pierleoni, Universita' dell'Aquila (Italy)

**HPC Platform:** Hermit of HLRS - **Date published:** March 2014

**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.

**Principal Investigator:** Zoltán Fodor, Institut für Theoretische Physik, FB-C, Universität Münster (Germany)

**HPC Platform:** JUQUEEN of JSC - **Date Published:** February 2014

**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.

**Principal Investigator:** Szabolcs Borsányi, Institut für Theoretische Physik, FB-C, Universität Münster (Germany)

**HPC Platform:** JUQUEEN of JSC - **Date published:** February 2014

**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.

**Principal Investigator:** Christian Hölbling, Institut für Theoretische Physik, FB-C, Universität Wuppertal (Germany)

**HPC Platform:** JUQUEEN of JSC - **Date published:** February 2014

**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).

**Principal Investigator:** Christian Schmidt, Physics Department, University of Bielefeld (Germany)

**HPC Platform:** JUQUEEN of JSC - **Date published:** February 2014

**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.

**Principal Investigator:** Hartmut Wittig, Institut für Kernphysik, Universität Mainz (Germany)

**HPC Platform:** JUQUEEN of JSC - **Date published:** November 2013

**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.

**Principal Investigator:** Stephan Duerr, Wuppertal University and IAS/JSC at Forschungszentrum Jülich

**HPC Platform:** JUQUEEN of JSC - **Date published:** October 2013

**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.

**Principal Investigator:** Gerrit Schierholz, DESY, Hamburg (Germany)

**HPC Platform:** JUQUEEN of JSC - **Date published:** October 2013

**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.

**Principal Investigator:** Christian Hölbling, Institut für Theoretische Physik, FB-C, Universität Wuppertal (Germany)

**HPC Platform:** JUQUEEN of JSC - **Date published:** October 2013

**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.

**Principal Investigator:** Kálmán Szabó, Institut für Theoretische Physik, FB-C, Universität Wuppertal (Germany)

**HPC Platform: **JUQUEEN of JSC - **Date published:** October 2013

**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.

**Principal Investigator:** Christian Hölbling, Institut für Theoretische Physik, FB-C, Universität Wuppertal (Germany)

**HPC Platform:** JUQUEEN of JSC - **Date published:** July 2013

**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.

**Principal Investigator: ** Ulf-G. Meißner, Universität Bonn (HISKP) und FZ Jülich (IAS & IKP)

**HPC Platform:** JUQUEEN of JSC - **Date published:** July 2013

**More: The Synthesis of the Elements, in Particular Carbon …**