Description
Chair: Thomas Becher
In recent articles, the discussion on the treatment of Power Corrections in the three-jet limit, along with its influence on precision $\alpha_s$ determinations from fits to event shape experimental data, has attracted a lot of attention. On the basis of a factorization formula for the $e^+e^-$ thrust distribution, derived within soft-collinear effective theory, we discuss the treatment of...
We explore systematic effects of renormalon cancellation schemes and perturbative scale choices on extractions of the strong coupling constant $\alpha_s(m_Z)$ and the leading non-perturbative shift parameter $\Omega_1$ from resummed predictions of hadronic event shapes in electron-positron collisions. Our analysis is based on thrust distributions to N$^3$LL$'$ accuracy in resummed perturbation...
The interpretation of precision measurements requires theory predictions with reliable and meaningful uncertainties and in particular correct correlations. Theory correlations are for example essential when fitting to differential spectra, but our default scale-variation-based methods, among their many shortcomings, are incapable of providing correct correlations. This is becoming a severe...
We study the extraction of $\alpha_s$ from the $Z$ boson $p_T$ spectrum at low $p_T$ using resummed predictions up to N$^4$LL.
Recently, the ATLAS collaboration presented a new extracted value for $\alpha_s$ which has been somewhat controversial due to its rather small theoretical uncertainties.
We study in detail the various sources of uncertainty, including the perturbative uncertainty,...
