Renormalization of heavy-light currents in moving NRQCD

Abstract

Heavy-light decays such as $B\to \pi \ell \nu$, $B\to K^{\ast }\gamma$ and $B\to K^{(\ast )}\ell \ell$ can be used to constrain the parameters of the Standard Model and in indirect searches for new physics. While the precision of experimental results has improved over the last years this has still to be matched by equally precise theoretical predictions. The calculation of heavy-light form factors is currently carried out in lattice QCD. Due to its small Compton wavelength we discretize the heavy quark in an effective non-relativistic theory. By formulating the theory in a moving frame of reference discretization errors in the final state are reduced at large recoil. Over the last years the formalism has been improved and tested extensively. Systematic uncertainties are reduced by renormalizing the m(oving)NRQCD action and heavy-light decay operators. The theory differs from QCD only for large loop momenta at the order of the lattice cutoff and the calculation can be carried out in perturbation theory as an expansion in the strong coupling constant. In this paper we calculate the one loop corrections to the heavy-light vector and tensor operator. Due to the complexity of the action the generation of lattice Feynman rules is automated and loop integrals are solved by the adaptive Monte Carlo integrator VEGAS. We discuss the infrared and ultraviolet divergences in the loop integrals both in the continuum and on the lattice. The light quarks are discretized in the ASQTad and highly improved staggered quark (HISQ) action; the formalism is easily extended to other quark actions.

24 pages, 11 figures. Published in Phys. Rev. D. Corrected a typo in eqn. (51)

References in corpus (12)

• Estimate of BR(B -> X_s gamma) at O(alpha_s^2)
• Highly Improved Staggered Quarks on the Lattice, with Applications to Charm Physics
• B->V gamma Beyond QCD Factorisation
• The B -> pi l nu semileptonic form factor from three-flavor lattice QCD: A model-independent determination of |V(ub)|
• Analysis of Br(B-->X_s gamma) at NNLO with a Cut on Photon Energy
• Time-dependent CP Asymmetry in B->K* gamma as a (Quasi) Null Test of the Standard Model
• Towards $B\to V\gamma$ Decays at NNLO in SCET
• Time-Dependent CP Asymmetries in B0 -> Ks pi0 gamma transitions
• An estimate of the B-->K*gamma form factor
• Automatically generating Feynman rules for improved lattice field theories
• Moving NRQCD for heavy-to-light form factors on the lattice
• Leptonic widths of heavy quarkonia: S-Wave QCD/NRQCD matching coefficients for the electromagnetic vector annihilation current at O(alpha_s v^2)

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• The mass of the b-quark from lattice NRQCD and lattice perturbation theory
• A lattice calculation of B -> K(*) form factors
• Matching heavy-light currents with NRQCD and HISQ quarks
• The Beauty of Lattice Perturbation Theory: The Role of Lattice Perturbation Theory in B Physics