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Jorge Noronha

Publications and source records attributed to Jorge Noronha.

187 records · Page 11Linked to original sources
arXiv2008

Jet Energy Loss and Mach Cones in pQCD vs. AdS/CFT

We compare away-side hadron correlations with respect to tagged heavy quark jets computed within a weakly coupled pQCD and a strongly coupled AdS/CFT model. While both models feature similar far zone Mach and diffusion wakes, the far zone stress features are shown to be too weak to survive thermal broadening at hadron freeze-out. Observable away-side conical correlations are dominated by the jet-induced transverse flow in near zone "Neck" region, which differs significantly for both models. Unlike in AdS/CFT, the induced transverse flow in the Neck zone is too weak in pQCD to produce conical correlations after Cooper-Frye freeze-out. The observation of conical correlations violating Mach's law would favor the strongly-coupled AdS/CFT string drag dynamics, while their absence would favor weakly-coupled pQCD-based hydrodynamics.

hep-ph↗
arXiv2008

Near Zone Navier-Stokes Analysis of Heavy Quark Jet Quenching in an $\mathcal{N}$ =4 SYM Plasma

The near zone energy-momentum tensor of a supersonic heavy quark jet moving through a strongly-coupled $\mathcal{N}=4$ SYM plasma is analyzed in terms of first-order Navier-Stokes hydrodynamics. It is shown that the hydrodynamical description of the near quark region worsens with increasing quark velocities. For realistic quark velocities, $v=0.99$, the non-hydrodynamical region is located at a narrow band surrounding the quark with a width of approximately $3/πT$ in the direction parallel to the quark's motion and with a length of roughly $10/πT$ in the perpendicular direction. Our results can be interpreted as an indication of the presence of coherent Yang-Mills fields where deviation from hydrodynamics is at its maximum. In the region where hydrodynamics does provide a good description of the system's dynamics, the flow velocity is so small that all the nonlinear terms can be dropped. Our results, which are compatible with the thermalization timescales extracted from elliptic flow measurements, suggest that if AdS/CFT provides a good description of the RHIC system, the bulk of the quenched jet energy has more than enough time to locally thermalize and become encoded in the collective flow. The resulting flow pattern close to the quark, however, is shown to be considerably different than the superposition of Mach cones and diffusion wakes observed at large distances.

hep-ph↗
arXiv2008

Conical Di-jet Correlations from a Chromo-Viscous Neck in AdS/CFT

We show that Mach-like correlations from heavy quark jets in the Gubser et al AdS/CFT string drag model arise not from the expected (weak) hydrodynamical Mach sound wakes zone but from a near ``Neck'' zone where strong chromo-viscous field effects dominated and lead to a distinctive stress in the plasma of the form $T^{μν}_{Neck} \propto \surd λT_0^2 Y^{μν}(x)/x^2$. We propose that measurement of the jet velocity dependence of moderate $p_T$ hadrons associated with future {\em identified heavy quark jets} at RHIC and LHC could be used to look for this novel source of conical correlations which are unrelated to Mach's law.

hep-ph↗
arXiv2008

Near Zone Hydrodynamics of AdS/CFT Jet Wakes

The energy-momentum tensor of a supersonic heavy quark jet moving through a strongly-coupled $\mathcal{N}=4$ SYM plasma is analyzed in terms of first-order Navier-Stokes hydrodynamics. We focus on the near zone ``head'' region close to the heavy quark where deviations from hydrodynamic behavior are expected to be large. For realistic quark velocities, $v=0.99$, we find that the non-hydrodynamical head region is confined at a narrow pancake surrounding the jet with a width $\sim 1/T$ and transverse radius $\sim 3/T$. Outside this jet head region, the jet induced stress is well approximated by Navier-Stokes hydrodynamics.

hep-ph↗
arXiv2008

Tkachenko modes as sources of quasiperiodic pulsar spin variations

We study the long wavelength shear modes (Tkachenko waves) of triangular lattices of singly quantized vortices in neutron star interiors taking into account the mutual friction between the superfluid and the normal fluid and the shear viscosity of the normal fluid. The set of Tkachenko modes that propagate in the plane orthogonal to the spin vector are weakly damped if the coupling between the superfluid and normal fluid is small. In strong coupling, their oscillation frequencies are lower and are undamped for small and moderate shear viscosities. The periods of these modes are consistent with the observed ~100-1000 day variations in spin of PSR 1828-11.

astro-ph↗
arXiv2007

Magnetization of Color-Flavor Locked Matter

We show that the magnetization in color-flavor locked superconductors can be so strong that homogeneous quark matter becomes metastable for a wide range of magnetic field values. This indicates that magnetic domains or other type of magnetic inhomogeneities can be present in the quark cores of magnetars.

hep-ph↗