What is the top quark mass?
Andre Hoang (University of Vienna)

The current controversial discussions concerning the interpretation of the top quark mass measurements from experimental reconstruction analyses at the LHC expresses the fact that the theory calculations (analytic or Monte Carlo) are, as far as the available theoretical precision is concerned, somewhat behind the current experimental precision. The controversy thus arises because the current theory uncertainties are judged differently by different theorists (but also experimentalists), which is a consequence of the fact that there is no universal way to estimate theoretical errors. The discussions should be seen as a motivation to push theory (but at the same time also experiments) further toward a better understanding concerning issues that have up to now not received much attention, mostly concerning soft gluon radiation and its interplay with electroweak effects mostly related to top quark decay. In this respect the top quark mass measurement problem is very special and complicated, particularly at the LHC, and will require a number of new conceptual developments.
In the talk I provide my view on the current status of the issue what the top quark mass is and recent results that approach the problem for the first time in a systematic and analytical way by a perturbative analysis of angular ordered parton showers.