We first compare different approaches to estimates of the magnitude of the chiral magnetic effect in relativistic heavy ion collisions and show that their main difference lies in the assumptions on the length of persistence of the magnetic field generated by the colliding nuclei. We then analyze recent measurements of the global polarization of $Lambda$ and $bar Lambda$ hyperons in terms of the bounds they set on the magnitude of the late time magnetic field.
Topological charge changing transitions can induce chirality in the quark-gluon plasma by the axial anomaly. We study the equilibrium response of the quark-gluon plasma in such a situation to an external magnetic field. To mimic the effect of the topological charge changing transitions we will introduce a chiral chemical potential. We will show that an electromagnetic current is generated along the magnetic field. This is the Chiral Magnetic Effect. We compute the magnitude of this current as a function of magnetic field, chirality, temperature, and baryon chemical potential.
Inhomogeneous chiral phase is discussed in the presence of the magnetic field. A topological aspect is pointed out for the complex order parameter, in relation to the spectral asymmetry of the Dirac operator. It induces an anomalous baryon number and extremely extends the region of the inhomogeneous chiral phase in the QCD phase diagram. It is also shown that the novel tricritical point appears at zero chemical potential, which should be examined by the lattice QCD simulation.
We investigate the properties of electromagnetic fields in isobaric $_{44}^{96}textrm{Ru}+,_{44}^{96}textrm{Ru}$ and $_{40}^{96}textrm{Zr}+,_{40}^{96}textrm{Zr}$ collisions at $sqrt{s}$ = 200 GeV by using a multiphase transport model, with special emphasis on the correlation between magnetic field direction and participant plane angle $Psi_{2}$ (or spectator plane angle $Psi_{2}^{rm SP}$), i.e. $langle{rm cos} 2(Psi_B - Psi_{2})rangle$ [or $langle{rm cos} 2(Psi_B - Psi_{2}^{rm SP})rangle$]. We confirm that the magnetic fields of $_{44}^{96}textrm{Ru}+,_{44}^{96}textrm{Ru}$ collisions are stronger than those of $_{40}^{96}textrm{Zr}+,_{40}^{96}textrm{Zr}$ collisions due to their larger proton fraction. We find that the deformation of nuclei has a non-negligible effect on $langle{rm cos} 2(Psi_B - Psi_{2})rangle$ especially in peripheral events. Because the magnetic-field direction is more strongly correlated with $Psi_{2}^{rm SP}$ than with $Psi_{2}$, the relative difference of the chiral magnetic effect observable with respect to $Psi_{2}^{rm SP}$ is expected to be able to reflect much cleaner information about the chiral magnetic effect with less influences of deformation.
We study the chiral magnetic effect (CME) in the hadronic phase. The CME current involves pseudoscalar mesons to modify its functional form. This conclusion is independent of microscopic details. The strength of the CME current in the hadronic phase would decrease for two flavors.
We investigate the effect of turning on temperature for the charge neutral phase of two-flavor color superconducting (2SC) dense quark matter in presence of constant external magnetic field. Within the Nambu-Jona-Lasinio model, by tuning the diquark coupling strength, we study the interdependent evolution of the quark Bardeen-Cooper-Schrieffer gap and dynamical mass as functions of temperature and magnetic field. We find that magnetic field $B gtrsim 0.02$ GeV$^2$ ($10^{18}$ G) leads to anomalous temperature behavior of the gap in the gapless 2SC phase (moderately strong coupling), reminiscent of previous results in the literature found in the limit of weak coupling without magnetic field. The 2SC gap in the strong coupling regime is abruptly quenched at ultrahigh magnetic field due to the mismatched Fermi surfaces of up and down quarks imposed by charge neutrality and oscillation of the gap due to Landau level quantization. The dynamical quark mass also displays strong oscillation and magnetic catalysis at high magnetic field, although the latter effect is tempered by nonzero temperature. We discuss the implications for newly born compact stars with superconducting quark cores.
Berndt Muller
,Andreas Schafer
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(2018)
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"The Chiral Magnetic Effect and an experimental bound on the late time magnetic field strength"
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Berndt Muller
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