466 citations · 3.3k across the 64 of their papers we have counts for
64 papers
Multi-channel phase space with Feynman-diagram-gauge amplitudes
Kaoru Hagiwara, Junichi Kanzaki, Fabio Maltoni +2
Multi-channel phase space with a single Feynman diagram enhancement is a powerful tool for high-energy physics event generation if a diagram with a singular propagator dominates th…
Automatic generation of helicity amplitudes in Feynman-Diagram gauge
Kaoru Hagiwara, Junichi Kanzaki, Olivier Mattelaer +2
We develop a method to calculate helicity amplitudes of an arbitrary tree-level process in Feynman-Diagram (FD) gauge for an arbitrary gauge model with MadGraph5_aMC@NLO. We start…
Helicity amplitudes in light-cone and Feynman-diagram gauges
Junmou Chen, Kaoru Hagiwara, Junichi Kanzaki +2
Recently proposed Feynman-diagram (FD) gauge propagator for massless and massive gauge bosons is obtained from a light-cone (LC) gauge propagator, by choosing the gauge vector alon…
Helicity amplitudes without gauge cancellation for electroweak processes
Junmou Chen, Kaoru Hagiwara, Junichi Kanzaki +1
In the 5-component representation of weak bosons, the first four components make a Lorentz four vector, representing the transverse and longitudinal polarizations excluding the sca…
QED and QCD helicity amplitudes in parton-shower gauge
Kaoru Hagiwara, Junichi Kanzaki, Kentarou Mawatari
We introduce photon and gluon propagators in which the scalar polarization component is subtracted systematically by making use of the BRST invariance of the off-shell vector boson…
Computing for Perturbative QCD - A Snowmass White Paper
Christian Bauer, Zvi Bern, Radja Boughezal +18
We present a study on high-performance computing and large-scale distributed computing for perturbative QCD calculations.
Fast computation of MadGraph amplitudes on graphics processing unit (GPU)
K. Hagiwara, J. Kanzaki, Q. Li +2
Continuing our previous studies on QED and QCD processes, we use the graphics processing unit (GPU) for fast calculations of helicity amplitudes for general Standard Model (SM) pro…
On the W+4 jets background to the top quark asymmetry at the Tevatron
Kaoru Hagiwara, Junichi Kanzaki, Yoshitaro Takaesu
We investigate the possibility that the W+4 jets background is a source of the anomalously large top-antitop (tt) charge asymmetry observed at the Tevatron. We simulate the tt reco…
Determination of αS using OPAL hadronic event shapes at sqrt(s) = 91 - 209 GeV and resummed NNLO calculations
The OPAL Collaboration
Hadronic event shape distributions from e+e- annihilation measured by the OPAL experiment at centre-of-mass energies between 91 GeV and 209 GeV are used to determine the strong cou…
Sigma-antihyperon correlations in Z0 decay and investigation of the baryon production mechanism
The OPAL Collaboration
Data collected around sqrt{s}=91 GeV by the OPAL experiment at the LEP e+e- collider are used to study the mechanism of baryon formation. As the signature, the fraction of Sigma-hy…
Calculation of HELAS amplitudes for QCD processes using graphics processing unit (GPU)
K. Hagiwara, J. Kanzaki, N. Okamura +2
We use a graphics processing unit (GPU) for fast calculations of helicity amplitudes of quark and gluon scattering processes in massless QCD. New HEGET ({\bf H}ELAS {\bf E}valuatio…
Fast calculation of HELAS amplitudes using graphics processing unit (GPU)
K. Hagiwara, J. Kanzaki, N. Okamura +2
We use the graphics processing unit (GPU) for fast calculations of helicity amplitudes of physics processes. As our first attempt, we compute ( to 8) processe…
Inclusive Jet Production in Photon-Photon Collisions at sqrt(s_ee) from 189 to 209 GeV
The OPAL collaboration
Inclusive jet production (e+e- -> e+e- +jet+X) is studied in collisions of quasi-real photons radiated by the LEP beams at e+e- centre-of-mass energies sqrt see from 189 to 209 GeV…
QCD coherence and correlations of particles with restricted momenta in hadronic Z decays
The OPAL collaboration, G. Abbiendi
QCD coherence effects are studied based on measurements of correlations of particles with either restricted transverse momenta, pT<pTcut, where pT is defined with respect to the th…
Measurement of event shape distributions and moments in e+e- -> hadrons at 91-209 GeV and a determination of alpha_s
The OPAL Collaboration, G. Abbiendi
We have studied hadronic events from e+e- annihilation data at centre-of-mass energies from 91 to 209 GeV. We present distributions of event shape observables and their moments at…
Study of Black Holes with the ATLAS detector at the LHC
Junichi Tanaka, Taiki Yamamura, Shoji Asai +1
We evaluate the potential of the ATLAS detector for discovering black holes produced at the LHC, as predicted in models with large extra dimensions where quantum gravity is at the…
Prospects for the Search for a Standard Model Higgs Boson in ATLAS using Vector Boson Fusion
S. Asai, G. Azuelos, C. Buttar +14
The potential for the discovery of a Standard Model Higgs boson in the mass range m_H < 2 m_Z in the vector boson fusion mode has been studied for the ATLAS experiment at the LHC.…
Search for Stable and Long-Lived Massive Charged Particles in e+e- Collisions at sqrt(s) = 183-209 GeV
The OPAL collaboration
A search for stable and long-lived massive particles of electric charge |Q/e|=1 or fractional charges of 2/3, 4/3, and 5/3 is reported using data collected by the OPAL detector at…
Test of non-commutative QED in the process e+e- -> gamma gamma at LEP
The OPAL collaboration
Non-commutative QED would lead to deviations from the Standard Model depending on a new energy scale Lambda_NC and a unique direction in space defined by two angles eta and xi. Her…
Measurement of Neutral-Current Four-Fermion Production at LEP2
The OPAL collaboration
Four-fermion final states qqbar e+e- and qqbar mu+mu- from neutral-current interactions in e+e- collisions are studied in the OPAL detector at LEP at centre-of-mass energies from 1…
Measurement of the Cross-Section for the Process GammaGamma -> Ppbar at sqrt(s)_ee=183-189 GeV at LEP
The OPAL collaboration, G. Abbiendi
The exclusive production of proton-antiproton pairs in the collisions of two quasi-real photons had been studied using data taken at sqrt(s)_ee=183 GeV and 189 GeV with the OPAL de…
Search for Scalar Top and Scalar Bottom Quarks at LEP
The OPAL collaboration, G. Abbiendi
Searches for a scalar top quark and a scalar bottom quark have been performed using a data sample of 438 pb-1 at centre-of-mass energies of sqrt(s) = 192 - 209 GeV collected with t…
Search for Associated Production of Massive States Decaying into Two Photonsin e+e- Annihilations at sqrt(s) = 88-209 GeV
The OPAL collaboration, G. Abbiendi
A search is performed for production of short-lived particles in e+e- -> XY, with X -> gamma gamma and Y -> ffbar, for scalar X and scalar or vector Y. Model-independent limits in…
Search for Charged Excited Leptons in e+e- Collisions at sqrt(s) = 183-209 GeV
The OPAL collaboration
A search for charged excited leptons decaying into a lepton and photon has been performed using approximately 680 pb-1 of e+e- collision data collected by the OPAL detector at LEP…