57 Result(s)

Chapter and Conference Paper

Parallel Computer Algebra and Feynman Integrals

Relativistic quantum field theories are the mathematical tools which are indispensable in modern particle physics. In particular in combination with perturbation theory, realized with the help of so-called Fey...

P. A. Baikov, K. G. Chetyrkin, J. H. Kühn… in High Performance Computing in Science and … (2013)

Article

Vector correlator in massless QCD at order \( \mathcal{O}\left( {\alpha_s^4} \right) \) and the QED β-function at five loop

We present a concise summary of recent results for the vector correlator in massless QCD at order $ \mathcal{O}\left( {\alpha_s^4} \ri...

P. A. Baikov, K. G. Chetyrkin, J. H. Kühn, J. Rittinger in Journal of High Energy Physics (2012)

Article

Precise charm- and bottom-quark masses: Theoretical and experimental uncertainties

We consider recent theoretical and experimental improvements in determining charm- and bottom-quark masses. We present a new, improved evaluation of the contribution of the gluon condensate 〈α _s

K. G. Chetyrkin, J. H. Kühn, A. Maier… in Theoretical and Mathematical Physics (2012)

Chapter and Conference Paper

Massive and Massless Four-Loop Integrals

The main focus of this project lies on the computation of four-loop Feynman diagrams, which appear in the evaluation of quantum corrections to various physical observables in modern elementary particle physics...

P. Baikov, K. Chetyrkin, J. H. Kühn… in High Performance Computing in Science and … (2012)

Article

Next-to-next-to-leading electroweak logarithms for W-pair production at LHC

We derive the high energy asymptotic of one-and two-loop corrections in the next-to-next-to-leading logarithmic approximation to the differential cross section of W-pair production at the LHC. For large invariant...

J. H. Kühn, F. Metzler, A. A. Penin, S. Uccirati in Journal of High Energy Physics (2011)

Chapter and Conference Paper

Massive and Massless Four-Loop Integrals

This is the report for the project ParFORM for the period June 2009 to June 2010.

J. H. Kühn, P. Marquard, M. Steinhauser… in High Performance Computing in Science and … (2011)

Article

Electroweak Sudakov logarithms and real gauge-boson radiation in the TeV region

Electroweak radiative corrections give rise to large negative, double-logarithmically enhanced corrections in the TeV region. These are partly compensated by real radiation and, moreover, affected by selecting...

G. Bell, J. H. Kühn, J. Rittinger in The European Physical Journal C (2010)

Article

Quest for precision in hadronic cross sections at low energy: Monte Carlo tools vs. experimental data

We present the achievements of the last years of the experimental and theoretical groups working on hadronic cross section measurements at the low-energy e ⁺ e ...

S. Actis, A. Arbuzov, G. Balossini, P. Beltrame… in The European Physical Journal C (2010)

Article

Top-quark pair production near threshold at LHC

The next-to-leading order analysis for the cross section for hadroproduction of top-quark pairs close to threshold is presented. Within the framework of non-relativistic QCD a significant enhancement compared ...

Y. Kiyo, J. H. Kühn, S. Moch, M. Steinhauser, P. Uwer in The European Physical Journal C (2009)

Chapter and Conference Paper

Massless Four-Loop Integrals and the Total Cross Section in e ⁺ e ⁻ Annihilation

J. H. Kühn, P. Marquard, M. Steinhauser… in High Performance Computing in Science and … (2009)

Chapter and Conference Paper

Massless Four-Loop Integrals and the Total Cross Section in e+ e− Annihilation

The main purpose of particle physics is the explanation of the fundamental mechanism for the interaction of the elementary particles. On the experimental side the investigations take mainly place at the big ac...

J.H. Kühn, M. Steinhauser, M. Tentyukov in High Performance Computing in Science and … (2008)

Article

Weak interaction effects in top-quark pair production at hadron colliders

Top-quark physics plays an important role at hadron colliders such as the Tevatron at Fermilab or the upcoming Large Hadron Collider (LHC) at CERN. Given the planned experimental precision, detailed theoretica...

J.H. Kühn, A. Scharf, P. Uwer in The European Physical Journal C (2007)

Article

Four-loop moments of the heavy quark vacuum polarization function in perturbative QCD

New results at four-loop order in perturbative QCD for the first two Taylor coefficients of the heavy quark vacuum polarization function are presented. They can be used to perform a precise determination of th...

K.G. Chetyrkin, J.H. Kühn, C. Sturm in The European Physical Journal C - Particle… (2006)

Article

Electron–positron annihilation into three pions and the radiative return

The Monte Carlo event generator PHOKHARA, which simulates hadron and muon production at electron–positron colliders through radiative return, has been extended to final states with three pions. A model for the...

H. Czyż, A. Grzelińska, J.H. Kühn… in The European Physical Journal C - Particle… (2006)

Article

Electroweak corrections to top-quark pair productionin quark-antiquark annihilation

Top-quark physics plays an important rôle at hadron colliders such as the Tevatron at Fermilab or the LHC at CERN. Given the planned precision at these colliders, precise theoretical predictions are required. ...

J. H. Kühn, A. Scharf, P. Uwer in The European Physical Journal C - Particles and Fields (2006)

Article

Heavy quark vacuum polarization: first two moments of the \({\mathcal{O}}(\alpha_s^3 n_f^2)\) contribution

The vacuum polarization due to a virtual heavy quark pair and specifically the coefficients of its Taylor expansion in the external momentum are closely related to moments of the cross section for quark-antiqu...

K. G. Chetyrkin, J. H. Kühn, P. Mastrolia… in The European Physical Journal C - Particle… (2005)

Article

Radiative return at \(\Phi\) - and B-factories: FSR for muon pair production at next-to-leading order

Muon pair production through the radiative return is of importance for a measurement of the hadronic production cross section in two ways: it provides an independent calibration and it may give rise to an impo...

H. Czyż, A. Grzelińska, J. H. Kühn… in The European Physical Journal C - Particle… (2005)