2023-06-02 11:00  7F Seminar Room

Fixed-target research at CERN as a tool for QCD studies: highlights from COMPASS and AMBER experiments

Dr. Stephane Platchkov

In the last two decades the COMPASS collaboration has collected a large amount of data with muon, pion and proton beams from the CERN SPS accelerator, using either polarized or unpolarized targets. With some modifications and several ongoing upgrades, its large experimental setup is now being operated by the newly formed AMBER collaboration. Both experiments aim at a better understanding of the structure of the hadrons and of the underlying theory of the strong interacting, QCD. While COMPASS has mainly concentrated on measurements of the nucleon distribution functions and spectroscopy, AMBER has evolved to more focused and specific experiments. Both research programs take advantage of the unique and versatile beamlines available at the CERN SPS. I will first recall some of the important physics results obtained recently by COMPASS on the nucleon and on its longitudinal and transverse degrees of freedom. I will also give an overview of the major physics motivations for the new AMBER experiment: a new precise measurement of the proton charge radius, as well as novel and extensive studies of the light mesons structure.