Showing papers by "Christopher T. Sachrajda published in 2011"
Kyoto University1, KEK2, Nagoya University3, Brookhaven National Laboratory4, Université Paris-Saclay5, University of Washington6, University of Connecticut7, University of Bern8, Spanish National Research Council9, University of Southern Denmark10, University of Rome Tor Vergata11, Forschungszentrum Jülich12, University of Wuppertal13, Osaka University14, San Francisco State University15, Indiana University16, Graduate University for Advanced Studies17, American Physical Society18, University of Edinburgh19, University of Southampton20, Aix-Marseille University21, National Chiao Tung University22, Roma Tre University23, Columbia University24, Autonomous University of Madrid25, University of Mainz26
TL;DR: The determination of the light-quark masses, the form factor, and the decay-constant ratio arising in semileptonic $$K \rightarrow \pi $$K→π transition at zero momentum transfer are reported on.
Abstract: We review lattice results related to pion, kaon, D- and B-meson physics with the aim of making them easily accessible to the particle physics community. More specifically, we report on the determination of the light-quark masses, the form factor f+(0), arising in semileptonic K -> pi transition at zero momentum transfer, as well as the decay constant ratio fK/fpi of decay constants and its consequences for the CKM matrix elements Vus and Vud. Furthermore, we describe the results obtained on the lattice for some of the low-energy constants of SU(2)LxSU(2)R and SU(3)LxSU(3)R Chiral Perturbation Theory and review the determination of the BK parameter of neutral kaon mixing. The inclusion of heavy-quark quantities significantly expands the FLAG scope with respect to the previous review. Therefore, for this review, we focus on D- and B-meson decay constants, form factors, and mixing parameters, since these are most relevant for the determination of CKM matrix elements and the global CKM unitarity-triangle fit. In addition we review the status of lattice determinations of the strong coupling constant alpha_s.
901 citations
TL;DR: In this article, physical results obtained from simulations using 2+1 flavors of domain wall quarks and the Iwasaki gauge action at two values of the lattice spacing a, (a −1 = 1.73 (3) GeV and a − 1 = 2.28 (3 ) GeV) were obtained.
Abstract: We present physical results obtained from simulations using 2+1 flavors of domain wall quarks and the Iwasaki gauge action at two values of the lattice spacing a, (a −1 = 1.73 (3) GeV and a −1 = 2.28 (3) GeV). On the coarser lattice, with 24 3 × 64× 16 points (where the 16 corresponds to Ls, the extent of the 5 th dimension inherent in the domain wall fermion (DWF) formulation
192 citations
TL;DR: In this paper, the first two moments of the light-cone distribution amplitudes of the pseudoscalar mesons and vector mesons were calculated as part of the UKQCD and RBC collaborations' domain-wall fermion phenomenology programme.
Abstract: As part of the UKQCD and RBC collaborations' ${N}_{f}=2+1$ domain-wall fermion phenomenology programme, we calculate the first two moments of the light-cone distribution amplitudes of the pseudoscalar mesons $\ensuremath{\pi}$ and $K$ and the (longitudinally polarized) vector mesons $\ensuremath{\rho}$, ${K}^{*}$, and $\ensuremath{\phi}$. We obtain the desired quantities with good precision and are able to discern the expected quark-mass dependence of SU(3)-flavor breaking effects. An important ingredient of the calculation is the nonperturbative renormalization of lattice operators using a regularization-independent momentum scheme.
102 citations
TL;DR: In this article, the authors reported a direct lattice calculation of the K to?? decay matrix elements for both the?I=1/2 and 3/2 amplitudes A0 and A2 on 2+1 flavor, domain wall fermion, 163×32×16 lattices.
Abstract: We report a direct lattice calculation of the K to ?? decay matrix elements for both the ?I=1/2 and 3/2 amplitudes A0 and A2 on 2+1 flavor, domain wall fermion, 163×32×16 lattices. This is a complete calculation in which all contractions for the required ten, four-quark operators are evaluated, including the disconnected graphs in which no quark line connects the initial kaon and final two-pion states. These lattice operators are nonperturbatively renormalized using the Rome-Southampton method and the quadratic divergences are studied and removed. This is an important but notoriously difficult calculation, requiring high statistics on a large volume. In this paper, we take a major step toward the computation of the physical K??? amplitudes by performing a complete calculation at unphysical kinematics with pions of mass 422 MeV at rest in the kaon rest frame. With this simplification, we are able to resolve Re(A0) from zero for the first time, with a 25% statistical error and can develop and evaluate methods for computing the complete, complex amplitude A0, a calculation central to understanding the ?=1/2 rule and testing the standard model of CP violation in the kaon system.
54 citations
06 Jun 2011
Abstract: In recent years the precision of lattice calculations has improved hugely, and the results are making a very significant impact in particle physics phenomenology. Indeed there is no alternative general method which can be used in the evaluation of nonperturbative strong interaction effects for a wide variety of physical processes. In this talk I discuss a selection of topics in flavour physics, including \textit{mature} quantities for which lattice calculations have been performed for a long time (e.g. the determination of the $V_{us}$ CKM matrix element and $B_K$), quantities which we are now learning to study (e.g. $K\to\pi\pi$ decays amplitudes and the spectrum and mixing of $\eta-\eta^\prime$ mesons) and important phenomenological quantities for which a large amount of experimental data is available but which we do not yet understand how to approach in lattice simulations (e.g. nonleptonic B-decays). The improvement in precision and the extension of the range of processes which can be studied using lattice QCD has to be continued vigorously if precision flavour physics is to play a complementary role to large $p_\perp$ discovery experiments at the LHC in unravelling the next level of fundamental physics.
9 citations
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TL;DR: In recent years the precision of lattice calculations has improved hugely, and the results are making a very significant impact in particle physics phenomenology as mentioned in this paper, and there is no alternative general method which can be used in the evaluation of nonperturbative strong interaction effects for a wide variety of physical processes.
Abstract: In recent years the precision of lattice calculations has improved hugely, and the results are making a very significant impact in particle physics phenomenology. Indeed there is no alternative general method which can be used in the evaluation of nonperturbative strong interaction effects for a wide variety of physical processes. In this talk I discuss a selection of topics in flavour physics, including \textit{mature} quantities for which lattice calculations have been performed for a long time (e.g. the determination of the $V_{us}$ CKM matrix element and $B_K$), quantities which we are now learning to study (e.g. $K\to\pi\pi$ decays amplitudes and the spectrum and mixing of $\eta-\eta^\prime$ mesons) and important phenomenological quantities for which a large amount of experimental data is available but which we do not yet understand how to approach in lattice simulations (e.g. nonleptonic B-decays). The improvement in precision and the extension of the range of processes which can be studied using lattice QCD has to be continued vigorously if precision flavour physics is to play a complementary role to large $p_\perp$ discovery experiments at the LHC in unravelling the next level of fundamental physics.
2 citations