PhD defence by Shi Qiu 'The Search for the Chiral Magnetic Effect with ALICE at the LHC'

On April 17 2024, Shi Qiu has successfully defended his thesis. He accomplished his PhD at the Institute for Gravitational and Subatomic Physics (GRASP), Heavy Ion Physics Group. The defense has taken place in the Academiegebouw in Utrecht.

Summary PhD thesis

The Search for the Chiral Magnetic Effect with ALICE at the LHC

This dissertation aims to explore the possibility of breaking a specific type of symmetry, known as parity symmetry, locally in quantum chromodynamics (QCD). This search is conducted using a distinct physical phenomenon: the chiral magnetic effect (CME). This effect might occur within strongly interacting systems, particularly the quark-gluon plasma created in heavy-ion collisions. In the earliest moments after non-central heavy-ion collisions—where the incoming ions do not fully overlap—an extremely strong magnetic field is produced by the spectator protons that are not involved in the collision. This is similar to the magnetic field created by two parallel wires with current flowing through them. The CME results in the generation of an electric current along the direction of this magnetic field.

Our results, obtained using the ALICE detector, one of the four major experiments at the Large Hadron Collider (LHC) at CERN, show that the experimental data align with the scenario in which the CME is absent. Nonetheless, the current obtained precision does not completely rule out the CME effect, particularly if its signal is small.

PhD supervisors: Prof. dr. R.J.M. Snellings, Dr. P.G. Kuijer and Dr. P. Christakoglou