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We compute the ratio between the scale $\Lambda_L$ associated with a lattice formulation of QCD using the overlap-Dirac operator, and $\Lambda_{MS-bar}$. To this end, the one-loop relation between the lattice coupling $g_0$ and the coupling…

High Energy Physics - Lattice · Physics 2015-06-25 C. Alexandrou , E. Follana , H. Panagopoulos , E. Vicari

We present a full off-shell NLO QCD calculation of $pp \rightarrow e^+ \nu_e b \mu^- \bar{\nu}_\mu \bar{b} b \bar{b} + X$. Results are obtained using the HELAC-NLO Monte Carlo framework. We discuss a comparison to previous results and to…

High Energy Physics - Phenomenology · Physics 2021-11-03 Michele Lupattelli

We combine the known asymptotic behaviour of the QCD perturbation series expansion, which relates the pole mass of a heavy quark to the MSbar mass, with the exact series coefficients up to the four-loop order to determine the ultimate…

High Energy Physics - Phenomenology · Physics 2017-11-22 M. Beneke , P. Marquard , P. Nason , M. Steinhauser

We use QCD sum rules to analyze the semileptonic transition $B \to \pi \ell \nu$ in the limit $m_b \to \infty$. We derive the dependence of the form factor $F_1(0)$ on the heavy quark mass, which is compatible with the expected dependence…

High Energy Physics - Phenomenology · Physics 2010-11-01 P. Colangelo , P. Santorelli

Over the past two years, the use of on-shell techniques has deepened our understanding of the S-matrix of gauge theories and led to the calculation of many new scattering amplitudes. In these notes we review a particular on-shell method…

High Energy Physics - Theory · Physics 2017-08-23 Andreas Brandhuber , Gabriele Travaglini

In this paper, we describe a numerical approach to evaluate Feynman loop integrals. In this approach the key technique is a combination of a numerical integration method and a numerical extrapolation method. Since the computation is carried…

High Energy Physics - Phenomenology · Physics 2011-09-21 F. Yuasa , T. Ishikawa , Y. Kurihara , J. Fujimoto , Y. Shimizu , N. Hamaguchi , E. de Doncker , K. Kato

In lattice QCD it is possible, in principle, to determine the parameters in the effective chiral lagrangian (including weak interaction couplings) by performing numerical simulations in the $\epsilon$--regime, i.e. at quark masses where the…

High Energy Physics - Lattice · Physics 2011-07-19 L. Giusti , C. Hoelbling , M. Lüscher , H. Wittig

Observables involving heavy quarks can be computed in perturbative QCD in two different approximation schemes: either the quark mass dependence is fully retained, or it is retained only where needed to regulate the collinear singularity.…

High Energy Physics - Phenomenology · Physics 2022-09-12 Daniele Gaggero , Andrea Ghira , Simone Marzani , Giovanni Ridolfi

Usually the simulation of scattering processes in lattice QCD is carried out at unphysically high values of the quark masses. Hence, a method to extrapolate data obtained in lattice calculations to physical masses is needed to allow for…

High Energy Physics - Phenomenology · Physics 2019-02-28 Malwin Niehus , Martin Hoferichter , Bastian Kubis

The calculation of exclusive observables beyond the one-loop level requires elaborate techniques for the computation of multi-leg two-loop integrals. We discuss how the large number of different integrals appearing in actual two-loop…

High Energy Physics - Phenomenology · Physics 2008-11-26 T. Gehrmann , E. Remiddi

A first study of numerical Monte Carlo simulations with two quark doublets, a mass-degenerate one and a mass-split one, interpreted as u, d, s and c quarks, is carried out in the framework of the twisted mass Wilson lattice formulation.…

High Energy Physics - Lattice · Physics 2008-11-26 T. Chiarappa , F. Farchioni , K. Jansen , I. Montvay , E. E. Scholz , L. Scorzato , T. Sudmann , C. Urbach

The 3-loop heavy flavor corrections to deep-inelastic scattering are essential for consistent next-to-next-to-leading order QCD analyses. We report on the present status of the calculation of these corrections at large virtualities $Q^2$.…

High Energy Physics - Phenomenology · Physics 2014-11-21 J. Blümlein , A. De Freitas , C. Schneider

We present a strategy designed to separate several possible origins of the well-known enhancement of the Delta{I}=1/2 amplitude in non-leptonic kaon decays. In particular, we seek to disentangle the contribution of physics at the typical…

High Energy Physics - Lattice · Physics 2008-11-26 L. Giusti , P. Hernandez , M. Laine , P. Weisz , H. Wittig

We compute the electromagnetic mass differences of mesons containing a single heavy quark in terms of measurable data using QCD-based arguments in heavy-quark effective theory. We derive an unsubtracted dispersion relation that shows that…

High Energy Physics - Phenomenology · Physics 2016-09-01 Markus A. Luty , Raman Sundrum

The shell-model Monte Carlo (SMMC) technique transforms the traditional nuclear shell-model problem into a path-integral over auxiliary fields. We describe below the method and its applications to four physics issues: calculations of sdpf-…

Nuclear Theory · Physics 2009-10-31 D. J. Dean , J. A. White

At small lattice spacing, or when using overlap fermions, lattice QCD simulations tend to become stuck in a single topological sector. Physical observables, e.g.\ hadron masses, then differ from their full QCD counterparts by $1/V$…

High Energy Physics - Lattice · Physics 2014-10-03 Christopher Czaban , Arthur Dromard , Marc Wagner

We present an analytic computation of the two-loop QCD corrections to $u\bar{d}\to W^+b\bar{b}$ for an on-shell $W$-boson using the leading colour and massless bottom quark approximations. We perform an integration-by-parts reduction of the…

High Energy Physics - Phenomenology · Physics 2021-10-14 Simon Badger , Heribertus Bayu Hartanto , Simone Zoia

A new Quantum Monte-Carlo (QMC) approach is proposed to investigate low-lying states of nuclei within the shell model. The formalism relies on a variational symmetry-restored wave-function to guide the underlying Brownian motion. Sign/phase…

Nuclear Theory · Physics 2015-10-20 Jérémy Bonnard , Olivier Juillet

Recently the four-loop perturbative QCD contributions to the relations between pole and running masses of charm, bottom and top quarks were evaluated in the $\rm{\overline{MS}}$-scheme with identical numerical error bars. In this work the…

High Energy Physics - Phenomenology · Physics 2016-07-18 A. L. Kataev , V. S. Molokoedov

Quark mass determinations based on lattice QCD simulations have continued to make strides in recent years. Here I review that progress with a focus on developments computing the charm (and bottom) quark masses since the 2015 edition of…

High Energy Physics - Lattice · Physics 2021-12-21 Andrew T. Lytle