Abstract
We report the first measurement of rapidity-odd directed flow () for and mesons at midrapidity () in collisions at using the STAR detector at the Relativistic Heavy Ion Collider. In 10–80% collisions, the slope of the rapidity dependence (), averaged over and mesons, is for transverse momentum above . The absolute value of meson is about 25 times larger than that for charged kaons, with significance. These data give a unique insight into the initial tilt of the produced matter, and offer constraints on the geometric and transport parameters of the hot QCD medium created in relativistic heavy-ion collisions.
- Received 6 May 2019
- Revised 9 August 2019
DOI:https://doi.org/10.1103/PhysRevLett.123.162301
© 2019 American Physical Society