English
Related papers

Related papers: Looking through the QCD Conformal Window with Pert…

200 papers

We test here our recently introduced new lattice method for the $\beta$-function defined over infinite Euclidean space-time in the continuum from scale changes generated by infinitesimal or finite steps of the renormalized gauge coupling on…

High Energy Physics - Lattice · Physics 2023-01-18 Chik Him Wong , Szabolcs Borsanyi , Zoltan Fodor , Kieran Holland , Julius Kuti

In previous work, a class of noninvertible topological dynamical systems $f: X \to X$ was introduced and studied; we called these {\em topologically coarse expanding conformal} systems. To such a system is naturally associated a preferred…

Dynamical Systems · Mathematics 2013-02-11 Peter Haissinsky , Kevin M. Pilgrim

We have computed the five-loop corrections to the scale dependence of the renormalized coupling constant for Quantum Chromodynamics (QCD), its generalization to non-Abelian gauge theories with a simple compact Lie group, and for Quantum…

High Energy Physics - Phenomenology · Physics 2017-03-08 F. Herzog , B. Ruijl , T. Ueda , J. A. M. Vermaseren , A. Vogt

We demonstrate how one can construct renormalizable perturbative expansion in formally nonrenormalizable higher dimensional scalar theories. It is based on 1/N-expansion and results in a logarithmically divergent perturbation theory in…

High Energy Physics - Theory · Physics 2007-05-23 D. I. Kazakov , G. S. Vartanov

In high-energy particle physics, extracting parton distribution functions (PDFs) from lattice quantum chromodynamics (QCD) calculations remains a significant challenge, particularly due to the divergent nature of perturbative expansions at…

High Energy Physics - Phenomenology · Physics 2024-11-26 Jia-Lu Zhang

Using a regularization by putting the system in finite volume, we develop a novel approach to form factor perturbation theory for nonintegrable models described as perturbations of integrable ones. This permits to go beyond first order in…

High Energy Physics - Theory · Physics 2009-11-09 G. Takacs

We consider an asymptotically free vectorial SU($N_c$) gauge theory with $N_f$ massless fermions in a representation $R$, having an infrared fixed point (IRFP) of the renormalization group at $\alpha_{IR}$ in the conformal non-Abelian…

High Energy Physics - Theory · Physics 2017-04-19 Thomas A. Ryttov , Robert Shrock

We report new results on nearly conformal gauge theories with fermions in the fundamental representation of the SU(3) color gauge group as the number of fermion flavors is varied in the Nf = 4-16 range. To unambiguously identify the…

High Energy Physics - Lattice · Physics 2009-11-05 Zoltan Fodor , Kieran Holland , Julius Kuti , Daniel Nogradi , Chris Schroeder

We discuss the violation of quark-flavor symmetry at high temperatures, induced from nonperturbative thermal loop corrections and axial anomaly, based on a three-flavor linear-sigma model including an axial-anomaly induced-flavor breaking…

High Energy Physics - Phenomenology · Physics 2021-03-31 Mamiya Kawaguchi , Shinya Matsuzaki , Akio Tomiya

We study the anomalous dimension of the cusped Maldacena-Wilson line in planar $\mathcal{N} = 4$ Yang-Mills theory with scalar insertions using the Quantum Spectral Curve (QSC) method. In the straight line limit we interpret the excited…

High Energy Physics - Theory · Physics 2020-08-26 David Grabner , Nikolay Gromov , Julius Julius

We calculate the chiral condensate of QCD at infinite coupling as a function of the number of fundamental fermion flavours using a lattice diagrammatic approach inspired by recent work of Tomboulis, and other work from the 80's. We outline…

High Energy Physics - Lattice · Physics 2015-02-18 Alexander S. Christensen , Joyce C. Myers , Peter D. Pedersen , Jan Rosseel

Perturbative QCD results in the MSbar scheme can be dramatically improved by switching to a scheme that accounts for the dominant power law dependence on the factorization scale in the operator product expansion. We introduce the ``MSR…

High Energy Physics - Phenomenology · Physics 2014-11-20 Andre H. Hoang , Ambar Jain , Ignazio Scimemi , Iain W. Stewart

The spectrum of twelve-flavor QCD has been studied in details by the LatKMI collaboration. In this proceeding we present our updated results for the spectrum obtained with the HISQ action at two lattice spacings, several volumes and fermion…

Non-Abelian flux tubes (strings) are well studied in N=2 supersymmetric QCD in (3+1) dimensions. In addition to translational zero modes they have also orientational moduli associated with rotations of their fluxes inside a non-Abelian…

High Energy Physics - Theory · Physics 2017-06-21 E. Ievlev , A. Yung

We assess the accuracy of our previous Asymptotic Pad\'e predictions of the five-loop QCD $\beta$-function and quark mass anomalous dimension in the light of subsequent exact results. We find the low-order coefficients in an expansion in…

High Energy Physics - Phenomenology · Physics 2026-04-10 J. A. Gracey , I. Jack , D. R. T. Jones

We have been studying QCD with 2 flavours of colour-sextet quarks to distinguish whether it is QCD-like or conformal. For comparison we are now studying QCD with 3 flavours of colour-sextet quarks, which is believed to be conformal in the…

High Energy Physics - Lattice · Physics 2013-05-30 J. B. Kogut , D. K. Sinclair

The recent QCD calculations of the five-loop beta function and of R(e+e-) to O(alpha_s^4) provide one more term in the Banks-Zaks expansion in (16.5-nf). There is no longer any hope that the expansion could extend, even crudely, to low nf.…

High Energy Physics - Phenomenology · Physics 2016-12-21 P. M. Stevenson

The cusp anomalous dimension is a ubiquitous quantity in four-dimensional gauge theories, ranging from QCD to maximally supersymmetric N=4 Yang-Mills theory, and it is one of the best investigated observables in the AdS/CFT correspondence.…

High Energy Physics - Theory · Physics 2009-06-19 B. Basso , G. P. Korchemsky

Conformal symmetry is broken in physical QCD; nevertheless, one can use conformal symmetry as a template, systematically correcting for its nonzero $\beta$ function as well as higher-twist effects. For example, commensurate scale relations…

High Energy Physics - Phenomenology · Physics 2017-08-23 Stanley J. Brodsky

We explore the Mellin representation of correlation functions in conformal field theories in the weak coupling regime. We provide a complete proof for a set of Feynman rules to write the Mellin amplitude for a general tree level Feynman…

High Energy Physics - Theory · Physics 2017-02-09 Amin A. Nizami , Arnab Rudra , Sourav Sarkar , Mritunjay Verma