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Topological susceptibility on the lattice and the three-flavour quark condensate
Bernard V., Descotes-Genon S., Toucas G.
JHEP 1206 (2012) 051 - http://hal.archives-ouvertes.fr/hal-00676446
Physique/Physique des Hautes Energies - Réseau
Physique/Physique des Hautes Energies - Phénoménologie
Topological susceptibility on the lattice and the three-flavour quark condensate
Veronique Bernard1, Sebastien Descotes-Genon2, Guillaume Toucas2
1 :  IPNO - Institut de Physique Nucléaire d'Orsay
http://ipnweb.in2p3.fr
CNRS : UMR8608 – IN2P3 – Université Paris XI - Paris Sud
IPN - 15, rue Georges Clemenceau - 91406 ORSAY CEDEX
France
2 :  LPT - Laboratoire de Physique Théorique d'Orsay [Orsay]
CNRS : UMR8627 – Université Paris XI - Paris Sud
Bâtiment 210 Université Paris XI 91405 Orsay Cedex
France
We reanalyse the topological susceptibility assuming the possibility of a significant paramagnetic suppression of the three-flavour quark condensate and a correlated enhancement of vacuum fluctuations of s s-bar pairs. Using the framework of resummed ChPT, we point out that simulations performed near the physical point, with a significant mass hierarchy between u,d and s dynamical quarks, are not able to disentangle the contributions from the quark condensate and sea s s-bar pair fluctuations, and that simulations with three light quark masses of the same order are better suited for this purpose. We perform a combined fit of recent RBC/UKQCD data on pseudoscalar masses and decay constants as well as the topological susceptibility, and we reconsider the determination of lattice spacings in our framework, working out the consequences on the parameters of the chiral Lagrangian. We obtain \Sigma(3;2 GeV)^1/3=241 +/- 15 MeV for the three-flavour quark condensate in the chiral limit. We notice a significant suppression compared to the two-flavour quark condensate \Sigma(2;2 GeV)/\Sigma(3;2 GeV)=1.65 +/- 0.12 and we confirm previous findings of a competition between leading order and next-to-leading order contributions in three-flavour chiral series.
Anglais
02/03/2012

JHEP
internationale
Articles dans des revues avec comité de lecture
2012
1206
051

6 figures, 28 pages
LPT-ORAY 12-20

Lien vers le texte intégral : 
http://fr.arXiv.org/abs/1203.0508