Quenched twisted mass QCD at small quark masses and in large volume

Abstract

As a test of quenched lattice twisted mass QCD, we compute the non-perturbatively O($a$) improved pseudoscalar and vector meson masses and the pseudoscalar decay constant down to $M_{\mathrm{PS}}/M_{\mathrm{V}}=0.467(13)$ at ${\hat{I}}^2=6$ in large volume. We check the absence of exceptional configurations and -- by further data at ${\hat{I}}^2=6.2$ -- the size of scaling violations. The CPU time cost for reaching a given accuracy is close to that with ordinary Wilson quarks at $M_{\mathrm{PS}}/M_{\mathrm{V}}\simeq 0.6$ and grows smoothly as $M_{\mathrm{PS}}/M_{\mathrm{V}}$ decreases.

4 pages, 3 figures, to appear in Nucl. Phys. B (Proc. Suppl.)