title: Paramagnetic squeezing of QCD matter.
abstract: We determine the magnetization of quantum chromodynamics for several temperatures around and above the transition between the hadronic and the quark-gluon phases of strongly interacting matter. We obtain a paramagnetic response that increases in strength with the temperature. We argue that due to this paramagnetism, chunks of quark-gluon plasma produced in noncentral heavy ion collisions should become squeezed perpendicular to the magnetic field. This anisotropy will then contribute to the elliptic flow v2 observed in such collisions, in addition to the pressure gradient that is usually taken into account. We present a simple estimate for the magnitude of this new effect and a rough comparison to the effect due to the initial collision geometry. We conclude that the paramagnetic effect might have a significant impact on the value of v2.
authors.affiliation: Institute for Theoretical Physics, Universität Regensburg, D-93040 Regensburg, Germany and Department of Theoretical Physics, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005, India.
authors.forename: G S
authors.initials: GS
authors.lastname: Bali
authors.affiliation: Institute for Theoretical Physics, Universität Regensburg, D-93040 Regensburg, Germany.
authors.forename: F
authors.initials: F
authors.lastname: Bruckmann
authors.affiliation: Institute for Theoretical Physics, Universität Regensburg, D-93040 Regensburg, Germany.
authors.forename: G
authors.initials: G
authors.lastname: Endrődi
authors.affiliation: Institute for Theoretical Physics, Universität Regensburg, D-93040 Regensburg, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Schäfer