The Institute for Theoretical Physics offers the following seminars:
Muonic hydrogen, a proton orbited by a negative muon, is one of the most basic atomic systems. A few years ago, we have measured the Lamb shift in muonic hydrogen (energy difference between 2S and 2P states) with infrared laser spectroscopy in a pioneering experiment at the Paul Scherrer Institute (PSI). Combined with QED calculations we determined the proton radius (root-mean-square charge radius). Our value is 4% smaller and deviates significantly from the previous values from electron-proton scattering and hydrogen spectroscopy. This discrepancy in a basic field of particle physics created a lot of theoretical investigations and initiated new experiments, but the "proton radius puzzle" is still unsolved today. I will give an overview about the present status, including new data from muonic deuterium and helium.
ETH Science City HPV G 4 - Wed 27.05.2015 16:15
We consider the long-standing problem of obtaining the 3-point functions of Toda CFT. Our main tools are topological strings and the AGT-W relation between gauge theories and 2D CFTs. Using the refined topological string formalism, we obtain the 5D partition functions for the T_N theories and provide the exact AGT-W dictionary that relates them to the Toda structure constants. Using a procedure known as Higgsing, we manage to obtain the formula of Fateev and Litvinov for the Toda structure constants with one semi-degenerate primary field.
ETH Science City HIT E 41.1 - Wed 27.05.2015 11:30
ETH Science City HIT E 41.1 - Tue 26.05.2015 11:15