Abstract
We discuss the chiral corrections to fB and BB with particular emphasis on determining the portion of the correction that arises from long distance physics. For very small pion and kaon masses all of the usual corrections are truly long distance, while for larger masses the long distance portion decreases. These chiral corrections have been used to extrapolate lattice calculations towards the physical region of lighter masses. We show in particular that the chiral extrapolation is better behaved if only the long distance portion of the correction is used. We also display the long distance portions of the infrared enhanced chiral logarithms that appear in partially quenched chiral perturbation theory.
Highlights
Lattice calculations of B meson properties are presently done with parameters such that the light quark masses are larger than their physical values
Chiral perturbation theory will be useless as a description of the spectral function and the data reveals the resonances of QCD as the appropriate short distance physics
The chiral extrapolation of lattice calculations is a tricky subject because the regions of validity of chiral loops and of present lattice simulations do not overlap significantly
Summary
Lattice calculations of B meson properties are presently done with parameters such that the light quark masses are larger than their physical values. One of the extrapolation methods uses some results from chiral perturbation theory, and this appears to produce rather large effects due to the chiral corrections. Chiral perturbation theory is not a good model of physics at short distances and is not valid for large meson masses. The analysis that we present below indicates that the lattice has not yet reached the region where the chiral formulas apply and that the current extrapolation is being driven by “nonsense” physics that comes from the chiral loops at short distance, which chiral perturbation theory is not able to describe. When applied at large quark masses, our formulas must be considered as a model It is a relatively innocuous model in that it makes no assumptions about short distance physics and it produces a small correction since the loop effect decouples at large mass. We attempt to contribute to this important topic by a fuller discussion of the need for a modified analysis and of the rationale behind the solution of keeping only the long distance corrections
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
