Is decay constant?

Pion mass and decay constant

Independent of assumptions about the form of the quark-antiquark scattering kernel we derive the explicit relation between the pion Bethe-Salpeter amplitude, Γπ, and the quark propagator in the chiral limit; Γπ necessarily involves a non-negligible γ5γ · P term (P is the pion four-momentum). We also obtain exact expressions for the pion decay constant, fπ, and mass, both of which depend on Γπ; ...

Pseudoscalar decay constant in heavy light systems

When investigating the physics of the heavy light mesonic system within the frame work of non-relativistic QCD (NRQCD), the action and observables are expanded in powers of ΛQCD/MQ, MQ denoting the heavy quark mass. If the regularisation, in our case the lattice cutoff, would be removed, divergences will arise in the matrix elements and coefficients of the expansion. To circumvent this, we keep...

Leptonic constant from B meson radiative decay

We propose a method to determine the leptonic decay constant fB∗ in the infinite heavy quark mass limit from the analysis of the radiative decay mode B− → lν̄lγ. The method relies on HQET symmetries and on experimental data from D∗0 → Dγ. E-mail address: [email protected] The measurement of fB and fB∗ , the leptonic decay constants of the B and B ∗ mesons, defined by the matrix elements: < ...

Measurement of the Pseudoscalar Decay Constant

Spontaneous Decay of the Effective Cosmological Constant

We discuss the notion that quantum fields may induce an effective time dependent cosmological constant which decays from a large initial value. It is shown that such cosmological models are viable in a non de Sitter spacetime.