Joint Seminar in Nuclear Physics

PROGRAM

14:15 - 14:30  Refreshments + Organization

15:00 - 15:50  "Measurement of the charged-pion polarizability at CERN COMPASS", Murray Moinester, Tel Aviv University

Abstract:

The pion polarizability is of fundamental interest in the low-energy sector of quantum chromodynamics. It is directly linked to the quark-gluon substructure and dynamics of the pion, the lightest bound system of the strong interaction. For more than a decade, COMPASS has been tackling the measurement of the electromagnetic polarizability of the charged pion, which describes the stiffness of the pion against deformation in electromagnetic fields. Previous experiments date back to the 1980's in Serpheukhov (Russia), where the Primakoff method for realizing interactions of charged pions with  quasi-real photons was first employed. Later, other measurements based on photon-nucleon and photon-photon collisions were also carried out at different laboratories.

The COMPASS measurement demonstrates that the charged-pion polarizability is significantly smaller than the previous results, roughly by a factor two, with the smallest uncertainties realized so far.

15:50 - 16:10 Coffee Break

16:10 - 17:00  "The Problem of radiation-reaction", Yaron Hadad, Tel Aviv University

Abstract:

The problem of radiation-reaction plagued classical electromagnetism since it was introduced by Maxwell in 1861. Radiation-reaction is the recoil force exerted on an accelerating charge by its own radiation field.

In the last century radiation-reaction resisted more than a dozen of attempts on a solution, most notably by Dirac, Landau & Lifshitz.

In this talk, I will present a historical account of the problem of radiation-reaction, both in the context of classical and quantum electrodynamics. I will also discuss how radiation-reaction can finally be put to an experimental test using high intensity lasers.