Searcharxiv⌕ Search

arXiv subjects

C. -J. David Lin

Publications and source records attributed to C. -J. David Lin.

115 records · Page 7Linked to original sources

Heavy meson chiral perturbation theory in finite volume

We study finite volume effects in heavy quark systems in the framework of heavy meson chiral perturbation theory for full, quenched, and partially quenched QCD. A novel feature of this investigation is the role played by the scales Delta and delta_s, where Delta is the mass difference between the heavy-light vector and pseudoscalar mesons of the same quark content, and delta_s is the mass difference due to light flavour SU(3) breaking. The primary conclusion of this work is that finite volume effects arising from the propagation of Goldstone particles in the effective theory can be altered by the presence of these scales. Since Delta varies significantly with the heavy quark mass, these volume effects can be amplified in both heavy and light quark mass extrapolations (interpolations). As an explicit example, we present results for B parameters of neutral B meson mixing matrix elements and heavy-light decay constants to one-loop order in finite volume heavy meson chiral perturbation theory for full, quenched, and N_f=2+1 partially quenched QCD. Our calculation shows that for high-precision determinations of the phenomenologically interesting SU(3) breaking ratios, finite volume effects are significant in quenched and not negligible in partially quenched QCD, although they are generally small in full QCD.

hep-lat↗

A note on the power divergence in lattice calculations of $ΔI = 1/2$ $K\toππ$ amplitudes at $M_{K}=M_π$

In this note, we clarify a point concerning the power divergence in lattice calculations of $ΔI = 1/2$ $K\toππ$ decay amplitudes. There have been worries that this divergence might show up in the Minkowski amplitudes at $M_{K}=M_π$ with all the mesons at rest. Here we demonstrate, via an explicit calculation in leading-order Chiral Perturbation Theory, that the power divergence is absent at the above kinematic point, as predicted by CPS symmetry.

hep-lat↗

Standard Model Matrix Elements for Neutral B-Meson Mixing and Associated Decay Constants

We present results of quenched lattice calculations of the matrix elements relevant for B_d-\bar B_d and B_s-\bar B_s mixing in the Standard Model. Results for the corresponding SU(3)-breaking ratios, which can be used to constrain or determine |V_{td}|, are also given. The calculations are performed at two values of the lattice spacing, corresponding to β= 6.0 and β= 6.2, with quarks described by a mean-field-improved Sheikholeslami-Wohlert action. As a by-product, we obtain the leptonic decay constants of B and D mesons. We also present matrix elements relevant for D^0-\bar D^0 mixing. Our results are summarized in the Introduction.

hep-ph↗

B-\bar{B} Mixing and b Hadron Lifetimes from Lattice QCD

We discuss neutral B_{s,d} meson mixing and b-hadron lifetimes from the perspective of recent lattice calculations. In particular, we consider matrix elements which can be combined with measured ΔM_{s,d} to constrain |V_{td}|, the lifetime ratios τ(Λ_b)/τ(B_d) and τ(B^-)/τ(B_d) and the lifetime difference, ΔΓ_s/Γ_s, in the neutral B_s meson system.

hep-ph↗

Neutral B Meson Mixing and Decay Constants from Lattice QCD

We present updates of our results for neutral $B$-meson mixing and leptonic decay constants obtained in the quenched approximation from a mean-field-improved Sheikholeslami-Wohlert action at two values of lattice spacing. We consider quantities such as $B_{B_{d(s)}}$, $f_{D_{(s)}}$, $f_{B_{(s)}}$ and the full $ΔB=2$ matrix-elements, as well as the corresponding SU(3)-breaking ratios.

hep-ph↗

Neutral B Meson Mixing and Heavy-light Decay Constants from Quenched Lattice QCD

We present high-statistics results for neutral $B$-meson mixing and heavy-light-meson leptonic decays in the quenched approximation from tadpole-improved clover actions at $β= 6.0$ and $β= 6.2$. We consider quantities such as $B_{B_{d(s)}}$, $f_{D_{d(s)}}$, $f_{B_{d(s)}}$ and the full $ΔB=2$ matrix elements as well as the corresponding SU(3)-breaking ratios. These quantities are important for determining the CKM matrix element $|V_{td}|$.

hep-lat↗

Delta S=2 and Delta I=3/2 Matrix Elements in Quenched QCD

We present preliminary results for B_K, B_7^{3/2} and B_8^{3/2} from two high-statistics lattice computations. These calculations are performed at beta=6.0 and 6.2 in the quenched approximation, using mean-field-improved Sheikholeslami-Wohlert fermionic actions.

hep-lat↗