Probing the electromagnetic fields in ultrarelativistic collisions with leptons from $Z^0$ decay and charmed mesons

Abstract

Ultrarelativistic heavy ion collisions are expected to generate a huge electromagnetic field, $eB\approx 10^{18}Gauss$, that induces a splitting of the directed flow, $v_1=⟨p_x/p_T⟩$, of charged particles and anti-particles. Such a splitting for charmed meson manifests even for neutral particle/anti-particles pairs ($D^0,{\overline{D}}^0$), hence being also a unique probe of the formation of the quark-gluon plasma phase. For the first time here we show that electromagnetic field may generate a $v_1(D^0)-v_1({\overline{D}}^0)$ as huge as the one recently observed at LHC against early expectations. Within this new research topic we point out a novel measurement: $v_1$ of leptons from $Z^0$ decay and its correlation to that of $D$ and $B$ mesons. The correlation for $\Delta v_1$ of $l^{+}-l^{-}$, $D^0-{\overline{D}}^0$ and $B^0-{\overline{B}}^0$ would provide a strong probe of the electromagnetic origin of the splitting and hence of the formation of a quark-gluon plasma phase with heavy quarks as degrees of freedom. The case of the $v_1(l^{\pm })$ presents features due to the peculiar form of the $p_T$ spectrum never appreciated before in the study of heavy ion collisions. We specifically predict a sudden change of the $\Delta v_1(p_T)$ of leptons at $p_T=45$ GeV$/c$, that can be traced back to a universal relation of $\Delta v_1$ with the slope of the $p_T$ particle distribution and the integrated effect of the Lorentz force.

6 pages, 4 figures

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Cited by in corpus (10)

• The Present and Future of QCD
• Charge-dependent flow as evidence of strong electromagnetic fields in heavy-ion collisions
• Probing the initial longitudinal density profile and electromagnetic field in ultrarelativistic heavy-ion collisions with heavy quarks
• Directed flow of D mesons at RHIC and LHC: non-perturbative dynamics, longitudinal bulk matter asymmetry and electromagnetic fields
• Thermal and thermoelectric responses of hot QCD medium in time-varying magnetic fields
• Directed flow of charged particles within idealized viscous hydrodynamics at energies available at the BNL Relativistic Heavy Ion Collider and at the CERN Large Hadron Collider
• Directed flow in relativistic resistive magneto-hydrodynamic expansion for symmetric and asymmetric collision systems
• External magnetic field induced paramagnetic squeezing effect in heavy-ion collisions at the LHC
• Interactions between heavy quarks and tilted QGP fireballs in 200 AGeV Au+Au collisions
• Directed flow induced by electromagnetic fields in heavy ion collisions