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Flavour singlet pseudoscalar masses in N_f = 2 QCD

T. Struckmann·K. Schilling·G. Bali·N. Eicker·S. Guesken·Th. Lippert·H. Neff·B. Orth·W. Schroers·J. Viehoff·P. Ueberholz
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Abstract

We perform a lattice mass analysis in the flavour singlet pseudoscalar channel on the SESAM and TXL full QCD vacuum configurations, with 2 active flavours of dynamical Wilson fermions at beta = 5.6. At our inverse lattice spacing, a^-1 = 2.3 GeV, we retrieve by a chiral extrapolation to the physical light quark masses the value m_eta' = 3.7(+8)(-4) m_pi. A crude extrapolation from (N_f = 3) phenomenology would suggest m_eta' \approx 5.1 m_pi for N_f = 2 QCD. we verify that the mass gap between the singlet state eta' and the pi flavour triplt state is due to gauge configurations with non-trivial topology.

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T. Struckmann, K. Schilling, G. Bali, N. Eicker, S. Guesken, Th. Lippert, H. Neff, B. Orth, W. Schroers, J. Viehoff, P. Ueberholz. 2000-10-05. Flavour singlet pseudoscalar masses in N_f = 2 QCD. https://doi.org/10.1103/physrevd.63.074503

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