Instanton dominance over $$a_s$$ at low momenta from lattice QCD simulations at $$N_f=0$$, $$N_f=2+1$$ and $$N_f=2+1+1$$
Abstract
We report on an instantonbased analysis of the gluon Green functions in the Landau gauge for low momenta; in particular we use lattice results for αs in the symmetric momentum subtraction scheme (MOM) for largevolume lattice simulations. We have exploited quenched gauge field configurations, Nf = 0, with both Wilson and treelevel Symanzik improved actions, and unquenched ones with Nf = 2 + 1 and Nf = 2 + 1 + 1 dynamical flavors (domain wall and twistedmass fermions, respectively).We show that the dominance of instanton correlations on the lowmomenta gluon Green functions can be applied to the determination of phenomenological parameters of the instanton liquid and, eventually, to a determination of the lattice spacing.We furthermore apply the Gradient Flow to remove shortdistance fluctuations. The Gradient Flow gets rid of the QCD scale, ΛQCD, and reveals that the instanton prediction extents to large momenta. For those gauge field configurations free of quantum fluctuations, the direct study of topological charge density shows the appearance of largescale lumps that can be identified as instantons, giving access to a direct study of the instanton density and size distribution that is compatible with those extracted from the analysis of the Green functions.
 Authors:

 Cyprus Institute, Nicosia, Cyprus
 Univ. ParisSud, Orsay (France)
 Univ. Pablo de Olavide, 41013 Sevilla; Spain; Univ. of Granada (Spain)
 Universidad de Huelva, 21071 Huelva; Spain; Univ. of Granada (Spain)
 College of William and Mary, Williamsburg, VA (United States); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Heidelberg Univ. (Germany). Inst. for Theoretische Physik
 Publication Date:
 Research Org.:
 Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
 Sponsoring Org.:
 USDOE Office of Science (SC), Nuclear Physics (NP) (SC26)
 OSTI Identifier:
 1434241
 Report Number(s):
 JLABTHY182689; DOE/OR/231774421; arXiv:1802.01342
 DOE Contract Number:
 AC0506OR23177
 Resource Type:
 Conference
 Journal Name:
 EPJ Web of Conferences
 Additional Journal Information:
 Journal Volume: 175; Conference: Lattice 2017, 35th International Symposium on Lattice Field Theory, 1824 Jun 2017. Granada, Spain
 Country of Publication:
 United States
 Language:
 English
Citation Formats
Athenodorou, Andreas, Boucaud, Philippe, de Soto, Feliciano, RodriguezQuintero, Jose, and Zafeiropoulos, Savvas. Instanton dominance over $a_s$ at low momenta from lattice QCD simulations at $N_f=0$, $N_f=2+1$ and $N_f=2+1+1$. United States: N. p., 2018.
Web. doi:10.1051/epjconf/201817512011.
Athenodorou, Andreas, Boucaud, Philippe, de Soto, Feliciano, RodriguezQuintero, Jose, & Zafeiropoulos, Savvas. Instanton dominance over $a_s$ at low momenta from lattice QCD simulations at $N_f=0$, $N_f=2+1$ and $N_f=2+1+1$. United States. doi:10.1051/epjconf/201817512011.
Athenodorou, Andreas, Boucaud, Philippe, de Soto, Feliciano, RodriguezQuintero, Jose, and Zafeiropoulos, Savvas. Sun .
"Instanton dominance over $a_s$ at low momenta from lattice QCD simulations at $N_f=0$, $N_f=2+1$ and $N_f=2+1+1$". United States. doi:10.1051/epjconf/201817512011. https://www.osti.gov/servlets/purl/1434241.
@article{osti_1434241,
title = {Instanton dominance over $a_s$ at low momenta from lattice QCD simulations at $N_f=0$, $N_f=2+1$ and $N_f=2+1+1$},
author = {Athenodorou, Andreas and Boucaud, Philippe and de Soto, Feliciano and RodriguezQuintero, Jose and Zafeiropoulos, Savvas},
abstractNote = {We report on an instantonbased analysis of the gluon Green functions in the Landau gauge for low momenta; in particular we use lattice results for αs in the symmetric momentum subtraction scheme (MOM) for largevolume lattice simulations. We have exploited quenched gauge field configurations, Nf = 0, with both Wilson and treelevel Symanzik improved actions, and unquenched ones with Nf = 2 + 1 and Nf = 2 + 1 + 1 dynamical flavors (domain wall and twistedmass fermions, respectively).We show that the dominance of instanton correlations on the lowmomenta gluon Green functions can be applied to the determination of phenomenological parameters of the instanton liquid and, eventually, to a determination of the lattice spacing.We furthermore apply the Gradient Flow to remove shortdistance fluctuations. The Gradient Flow gets rid of the QCD scale, ΛQCD, and reveals that the instanton prediction extents to large momenta. For those gauge field configurations free of quantum fluctuations, the direct study of topological charge density shows the appearance of largescale lumps that can be identified as instantons, giving access to a direct study of the instanton density and size distribution that is compatible with those extracted from the analysis of the Green functions.},
doi = {10.1051/epjconf/201817512011},
journal = {EPJ Web of Conferences},
number = ,
volume = 175,
place = {United States},
year = {2018},
month = {4}
}
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