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Related papers: Gradient flow and IR fixed point in SU(2) with Nf=…

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The Yang-Mills gradient flow in finite volume is used to define a running coupling scheme. As our main result the discrete beta-function, or step scaling function, is calculated for scale change s=3/2 at several lattice spacings for SU(3)…

High Energy Physics - Lattice · Physics 2012-11-15 Zoltan Fodor , Kieran Holland , Julius Kuti , Daniel Nogradi , Chik Him Wong

We present studies of the SU(2) gauge theory with 4, 6 and 10 fermion flavors. These models are expected to lie on both sides of the edge of the conformal window, where the theory has an infrared fixed point. We observe that the coupling…

High Energy Physics - Lattice · Physics 2012-10-17 Tuomas Karavirta , Kimmo tuominen , Jarno Rantaharju , Kari Rummukainen

SU(2) gauge theory with Nf=24 massless fermions is non-interacting at long distances, i.e. it has an infrared fixed point at vanishing coupling. With massive fermions the fermions are expected to decouple at energy scales below the fermion…

High Energy Physics - Lattice · Physics 2022-09-26 Tobias Rindlisbacher , Kari Rummukainen , Ahmed Salami , Kimmo Tuominen

Incorporated with twisted boundary condition, Polyakov loop correlators can give a definition of the renormalized coupling. We employ this scheme for the step scaling method (with step size s = 2) in the search of conformal fixed point of…

We consider measurement of the leading irrelevant scaling exponent $\gamma_g^\ast$, given by the slope of the beta function, at the fixed point of SU(2) gauge theory with six or eight flavors. We use the running coupling measured using the…

High Energy Physics - Lattice · Physics 2018-11-30 Viljami Leino , Kari Rummukainen , Kimmo Tuominen

We present strong numerical evidence for the existence of an infrared fixed point in the renormalization group flow of the SU(3) gauge-fermion system with twelve massless fermions in the fundamental representation. Our numerical simulations…

High Energy Physics - Lattice · Physics 2024-03-14 Curtis Taylor Peterson , Anna Hasenfratz

It is expected that SU(2) gauge theory with $N_f$ fundamental fermions has an infrared fixed point when $N_f$ is between $\sim 6$ and 10. We study the hadron spectrum and scale setting in SU(2) gauge field theory with $N_f=2,4,6$ using…

High Energy Physics - Lattice · Physics 2015-11-17 Alessandro Amato , Teemu Rantalaiho , Kari Rummukainen , Kimmo Tuominen , Sara Tähtinen

We discuss the setup and features of a new definition of the running coupling in the Schr\"odinger functional scheme based on the gradient flow. Its suitability for a precise continuum limit in QCD is demonstrated on a set of Nf=2 gauge…

High Energy Physics - Lattice · Physics 2015-06-16 Patrick Fritzsch , Alberto Ramos

We compute the renormalized running coupling of SU(3) gauge theory coupled to N_f = 8 flavors of massless fundamental Dirac fermions. The recently proposed finite volume gradient flow scheme is used. The calculations are performed at…

High Energy Physics - Lattice · Physics 2015-06-11 Zoltan Fodor , Kieran Holland , Julius Kuti , Santanu Mondal , Daniel Nogradi , Chik Him Wong

We measure the evolution of the coupling constant using the Schroedinger functional method in the lattice formulation of SU(2) gauge theory with two massless Dirac fermions in the adjoint representation. We observe strong evidence for an…

High Energy Physics - Lattice · Physics 2013-05-29 Ari J. Hietanen , Kari Rummukainen , Kimmo Tuominen

We simulate SU(2) gauge theory with two massless Dirac fermions in the adjoint representation. We calculate the running of the Schroedinger Functional coupling and the renormalised quark mass over a wide range of length scales. The running…

High Energy Physics - Phenomenology · Physics 2010-11-05 Francis Bursa , Luigi Del Debbio , Liam Keegan , Claudio Pica , Thomas Pickup

Nonperturbative determinations of the renormalization group (RG) $\beta$ function are crucial to understand properties of gauge-fermion systems at strong coupling and connect lattice simulations and the perturbative ultraviolet regime.…

High Energy Physics - Lattice · Physics 2023-01-11 Anna Hasenfratz , Claudio Rebbi , Oliver Witzel

We calculate the step scaling function, the lattice analog of the renormalization group $\beta$-function, for an SU(3) gauge theory with twelve flavors. The gauge coupling of this system runs very slowly, which is reflected in a small step…

High Energy Physics - Lattice · Physics 2019-12-25 Anna Hasenfratz , Claudio Rebbi , Oliver Witzel

We study the SU(3) gauge theory with twelve flavours of fermions in the fundamental representation as a prototype of non-Abelian gauge theories inside the conformal window. Guided by the pattern of underlying symmetries, chiral and…

High Energy Physics - Lattice · Physics 2015-06-23 M. P. Lombardo , K. Miura , T. J. Nunes da Silva , E. Pallante

We present details of a lattice study of infrared behaviour in SU(3) gauge theory with twelve massless fermions in the fundamental representation. Using the step-scaling method, we compute the coupling constant in this theory over a large…

High Energy Physics - Lattice · Physics 2012-08-22 C. -J. David Lin , Kenji Ogawa , Hiroshi Ohki , Eigo Shintani

We have measured the running coupling constant of SU(3) gauge theory coupled to Nf=2 flavors of symmetric representation fermions, using the Schrodinger functional scheme. Our lattice action is defined with hypercubic smeared links which,…

High Energy Physics - Lattice · Physics 2014-11-21 Thomas DeGrand , Yigal Shamir , Benjamin Svetitsky

The existence of a strongly coupled ultraviolet fixed point in 4-dimensional lattice models as they cross into the conformal window has long been hypothesized. The SU(3) gauge system with 8 fundamental fermions is a good candidate to study…

High Energy Physics - Lattice · Physics 2022-08-17 Anna Hasenfratz

We propose a new strategy for the determination of the step scaling function $\sigma(u)$ in finite size scaling studies using the Gradient Flow. In this approach the determination of $\sigma(u)$ is broken in two pieces: a change of the flow…

High Energy Physics - Lattice · Physics 2021-02-03 Alessandro Nada , Alberto Ramos

We investigate the discrete $\beta$ function of the 2-flavor SU(3) sextet model using the finite volume gradient flow scheme. Our results, using clover improved nHYP smeared Wilson fermions, follow the (non-universal) 4-loop…

High Energy Physics - Lattice · Physics 2015-07-30 Anna Hasenfratz , Yuzhi Liu , Cynthia Yu-Han Huang

We investigate the approach of pure SU(2) lattice gauge theory with the Wilson action to its continuum limit using the deconfining phase transition, the gradient flow and the cooling flow to set the scale. For the gradient and cooling…

High Energy Physics - Lattice · Physics 2017-05-24 Bernd A. Berg , David A. Clarke