Flavour symmetry restoration and kaon weak matrix elements in quenched twisted mass QCD

Abstract

We simulate two variants of quenched twisted mass QCD (tmQCD), with degenerate Wilson quarks of masses equal to or heavier than half the strange quark mass. We use Ward identities in order to measure the twist angles of the theory and thus check the quality of the tuning of mass parameters to a physics condition which stays constant as the lattice spacing is varied. Flavour symmetry breaking in tmQCD is studied in a framework of two fully twisted and two standard Wilson quark flavours, tuned to be degenerate in the continuum. Comparing pseudoscalar masses, obtained from connected quark diagrams made of tmQCD and/or standard Wilson quark propagators, we confirm that flavour symmetry breaking effects, which are at most 5%, decrease as we approach the continuum limit. We also compute the pseudoscalar decay constant in the continuum limit, with reduced systematics. As a consequence of improved tuning of the mass parameters at $\beta =6.1$, we reanalyse our previous $B_K$ results. Our main phenomenological findings are $r_0{f}_K=0.421(7)$ and ${\hat{B}}_K=0.735(71)$.

arXiv comment41 pages, figures included, one reference added. Final version as accepted for publication on Nucl.Phys.B

References in corpus (29)

• Chiral symmetry and O(a) improvement in lattice QCD
• Non-perturbative O(a) improvement of lattice QCD
• Chirally improving Wilson fermions II. Four-quark operators
• Dynamical Twisted Mass Fermions with Light Quarks
• Precision computation of the strange quark's mass in quenched QCD
• Non-Perturbative Renormalization of Lattice Four-Fermion Operators without Power Subtractions
• Kaon B parameter from quenched Lattice QCD
• Kaon B parameter from quenched domain-wall QCD
• O(a) improved twisted mass lattice QCD
• K^0-\bar K^0 mixing beyond the standard model and CP-violating electroweak penguins in quenched QCD with exact chiral symmetry
• A precise determination of the charm quark's mass in quenched QCD
• Hadron masses and matrix elements from the QCD Schr"odinger functional
• Twisted mass QCD and lattice approaches to the $\Delta I=1/2$ rule
• Kaon B Parameter in Quenched QCD
• Non-perturbative renormalization of static-light four-fermion operators in quenched lattice QCD
• Quenched Scaling of Wilson twisted mass fermions
• Non-perturbative Pion Matrix Element of a twist-2 operator from the Lattice
• The Kaon B-parameter from Quenched Domain-Wall QCD
• Strange quarks in quenched twisted mass lattice QCD
• Light quarks with twisted mass fermions
• A precise determination of $B_K$ in quenched QCD
• Lattice QCD with a chiral twist
• Exploring twisted mass Lattice QCD with the Clover term
• Non-perturbative renormalization of left-left four-fermion operators in quenched lattice QCD
• B_K from quenched QCD with exact chiral symmetry
• Scaling behavior of improvement and renormalization constants
• Testing improved staggered fermions with $m_s$ and $B_K$
• Non-perturbative renormalisation of left-left four-fermion operators with Neuberger fermions
• BK from the lattice with Wilson quarks

Cited by in corpus (14)

• FLAG Review 2019
• FLAG Review 2021
• Review of lattice results concerning low energy particle physics
• Twisted mass lattice QCD
• FLAG Review 2024
• BK-parameter from Nf = 2 twisted mass lattice QCD
• Non-perturbative renormalization of static-light four-fermion operators in quenched lattice QCD
• Non-perturbative renormalisation of Delta F=2 four-fermion operators in two-flavour QCD
• Non-leptonic kaon decays at large $N_c$
• Quenched $B_K$-parameter from Osterwalder-Seiler tmQCD quarks and mass-splitting discretization effects
• Precise determination of $B_K$ and light quark masses in quenched domain-wall QCD
• Progress in kaon physics on the lattice
• K^0-\bar{K}^0 Mixing Beyond the SM from Nf=2 tmQCD
• K* vector and tensor couplings from Nf = 2 tmQCD