Probe extreme (peta-Tesla) electromagnetic field with Breit-Wheeler process

by Prof. Zhangbu Xu (Shandong University, Brookhaven National Laboratory)

Monday 6 May 2019, 16:00 → 17:10 Asia/Shanghai

Meeting Room 410,TDLI（Tsung-Dao Lee Library）

Abstract

We presents first measurements of e+e−e+e− pair production from linearly polarized light-light scattering accompanying the creation of a Quark-Gluon Plasma in non-central high-energy heavy ion collisions. The yields peak distinctly at low transverse momentum between 40 to 60 MeV/c and show smooth mass distribution absent from any vector-meson contamination.The production can be explained quantitatively with exclusive Breit-Wheeler process, creating matter from pure lights. The measured pT distributions are significantly broader than model calculation for baseline ultra-peripheral collisions where hadronic interaction does not take place and are different between Au+Au and U+U collisions. Our experimental measurements withquantitative model calculations provide a possible tool to systematically study strong magnetic field at peta-Tesla scale controllable by varying the colliding impact parameter. Future polarization measurement related to the possible Vacuum birefringence will be discussed.

Biography

Prof. Zhangbu XU obtained his PhD degree from Yale Univ. (1999) and had been conducted his research on Experimental Heavy Ion Physics in Yale Univ. and later on in Brookhaven National Laboratory, where he received tenure in 2007 and he was appointed as BNL STAR Group leader since 2013 and tenured senior scientist since 2016. In 2014, he was co-appointed as a distinguished professor at Shandong Univ.

Prof. XU is a world-famous Heavy Ion experimentalist and received several prestigious awards and senior academic positions in large international collaborations such as:

DOE Achievement Award (2018)

Brookhaven Science and Technology Award (2010)

Presidential Early Career Awards for Scientists and Engineers (2004)

Spokesperson of STAR Collaboration (2014-Present) and T963, Fermilab (2007)

APS Fellow (2011) and Kavli Frontiers Fellow by National Academy of Science (2007)

Division

Particle and Nuclear