Publications (19)
Lattice QCD Applications on QPACE
Y. Nakamura, A. Nobile, D. Pleiter +4
QPACE is a novel massively parallel architecture optimized for lattice QCD simulations. A single QPACE node is based on the IBM PowerXCell 8i processor. The nodes are interconnecte…
Superconductivity and Crystal Structure of the Palladium-Iron-Arsenides Ca10(Fe1-xPdxAs)10Pd3As8
C. Hieke, J. Lippmann, T. Stürzer +5
The palladium-iron-arsenides Ca10(Fe1-xPdxAs)10(Pd3As8) were synthesized by solid state methods and characterized by X-ray powder and single crystal diffraction. The triclinic crys…
Charge Symmetry Breaking in Spin Dependent Parton Distributions and the Bjorken Sum Rule
I. C. Cloët, R. Horsley, J. T. Londergan +9
We present the first determination of charge symmetry violation (CSV) in the spin-dependent parton distribution functions of the nucleon. This is done by determining the first two…
Hyperon Form Factors from N_f=2+1 QCD
M. Göckeler, Ph. Hägler, R. Horsley +8
We present results from the QCDSF/UKQCD collaboration for the electromagnetic and semi-leptonic form factors for the hyperons. The simulations are performed on our new ensembles ge…
Status of the QPACE Project
H. Baier, H. Boettiger, M. Drochner +27
We give an overview of the QPACE project, which is pursuing the development of a massively parallel, scalable supercomputer for LQCD. The machine is a three-dimensional torus of id…
Nucleon form factors and structure functions
S. Collins, M. Göckeler, Ph. Hägler +13
We give an update on our ongoing efforts to compute the nucleon's form factors and moments of structure functions using Nf=2 flavours of non-perturbatively improved Clover fermions…
Hyperon sigma terms for 2+1 quark flavours
R. Horsley, Y. Nakamura, H. Perlt +7
QCD lattice simulations determine hadron masses as functions of the quark masses. From the gradients of these masses and using the Feynman-Hellmann theorem the hadron sigma terms c…
Flavour blindness and patterns of flavour symmetry breaking in lattice simulations of up, down and strange quarks
W. Bietenholz, V. Bornyakov, M. Göckeler +12
QCD lattice simulations with 2+1 flavours (when two quark flavours are mass degenerate) typically start at rather large up-down and strange quark masses and extrapolate first the s…
Charged multi-hadron systems in lattice QCD+QED
S. R. Beane, W. Detmold, R. Horsley +13
Systems with the quantum numbers of up to twelve charged and neutral pseudoscalar mesons, as well as one-, two-, and three-nucleon systems, are studied using dynamical lattice quan…
Flavour symmetry breaking and tuning the strange quark mass for 2+1 quark flavours
W. Bietenholz, V. Bornyakov, M. Göckeler +14
QCD lattice simulations with 2+1 flavours typically start at rather large up-down and strange quark masses and extrapolate first the strange quark mass to its physical value and th…
Dirac and Pauli form factors from lattice QCD
S. Collins, M. Göckeler, Ph. Hägler +11
We present a comprehensive analysis of the electromagnetic form factors of the nucleon from a lattice simulation with two flavors of dynamical O(a)-improved Wilson fermions. A key…
Structural and magnetic phase transitions in triclinic Ca10(FeAs)10(Pt3As8)
T. Stürzer, G. M. Friederichs, H. Luetkens +5
We report the structural and magnetic phase transitions of triclinic Ca10(FeAs)10(Pt3As8). High-resolution X-ray powder diffraction reveals splitting of the in-plane (a,b) lattice…
Spectra of heavy-light and heavy-heavy mesons containing charm quarks, including higher spin states for
G. Bali, S. Collins, S. Durr +18
We study the spectra of heavy-light and heavy-heavy mesons containing charm quarks, including higher spin states. We use two sets of gauge configurations, one set fro…
A Lattice Study of the Glue in the Nucleon
R. Horsley, R. Millo, Y. Nakamura +7
By introducing an additional operator into the action and using the Feynman-Hellmann theorem we describe a method to determine both the quark line connected and disconnected terms…
QPACE -- a QCD parallel computer based on Cell processors
H. Baier, H. Boettiger, M. Drochner +32
QPACE is a novel parallel computer which has been developed to be primarily used for lattice QCD simulations. The compute power is provided by the IBM PowerXCell 8i processor, an e…
Nucleon sigma terms for 2+1 quark flavours
R. Horsley, Y. Nakamura, H. Perlt +7
QCD lattice simulations yield hadron masses as functions of the quark masses. From the gradients of the hadron masses the sigma terms can then be determined. We consider here dynam…
Disconnected contributions to D-meson semi-leptonic decay form factors
G. S. Bali, S. Collins, R. Horsley +9
We calculate the disconnected contribution to the form factor for the semileptonic decay of a D-meson into a final state, containing a flavor singlet eta meson. We use QCDSF n_f=2+…
Charge Symmetry Breaking in Parton Distribution Functions from Lattice QCD
R. Horsley, Y. Nakamura, D. Pleiter +7
By determining the quark momentum fractions of the octet baryons from N_f=2+1 lattice simulations, we are able to predict the degree of charge symmetry violation in the parton dist…
Baryon Axial Charges and Momentum Fractions with N_f=2+1 Dynamical Fermions
M. Göckeler, Ph. Hägler, R. Horsley +8
We report on recent results of the QCDSF/UKQCD Collaboration on investigations of baryon structure using configurations generated with N_f=2+1 dynamical flavours of O(a) improved W…