arXiv subjects
Publications and source records attributed to A. Sinkovics.
I review the cancellation of non-perturbative 1/m_Q corrections to the heavy quark inclusive decay width. I summarize the results of an explicit second loop order calculation in perturbation theory which shows the absence of linear corrections when the decay width is expressed in terms of the short distance mass.
We consider the infrared sensitivity of the inclusive heavy quark decay width in perturbation theory. It is shown by explicit calculations to the second loop order (when the non-abelian nature of the QCD interactions first become apparent) that all infrared sensitive terms to logarithmic and linear accuracy cancel when the decay width is expressed in terms of the short distance mass. This in turn implies the absense of any non perturbative $1/m_Q$ power corrections to the decay width. The cancellation is shown algebraically at the level of the Feynman integrands without any use of an explicit infrared cutoff. This result is in accord with the implications of the KLN theorem.
The wave function of a light pseudoscalar meson is considered and nonperturbative corrections as signaled by perturbation theory are calculated. Two schemes are used, the massive gluon and the running coupling scheme. Both indicate the presence of leading power corrections of ${\cal O}(b^2)$, whose exponentiation leads to a Gaussian dependence of the wave function on the impact parameter $b$. The dependence of this correction on the light cone energy fractions of the quark and the antiquark is discussed and compared with other models for the meson.