Ariel Zhitnitsky

Charge separation induced by P-odd bubbles in QCD matter

Abstract We examine the recent suggestion that P - and CP -odd effects in QCD matter can induce electric charge asymmetry with respect to reaction plane in relativistic heavy ion collisions. General arguments are given which confirm that the angular momentum of QCD matter in the presence of nonzero topological charge should induce an electric field aligned along the axis of the angular momentum. A simple formula relating the magnitude of charge asymmetry to the angular momentum and topological charge is derived. The expected asymmetry is amenable to experimental observation at RHIC and LHC; we discuss the recent preliminary STAR result in light of our findings. Possible implications of charge separation phenomenon in cosmology and astrophysics are discussed as well.

Anomalous axion interactions and topological currents in dense matter

Recently an effective Lagrangian for the interactions of photons, Nambu-Goldstone bosons and superfluid phonons in dense quark matter has been derived using anomaly matching arguments. In this paper we illuminate the nature of certain anomalous terms in this Lagrangian by an explicit microscopic calculation. We also generalize the corresponding construction to introduce the axion field. We derive an anomalous axion effective Lagrangian describing the interactions of axions with photons and superfluid phonons in the dense matter background. This effective Lagrangian, among other things, implies that an axion current will be induced in the presence of magnetic field. We speculate that this current may be responsible for the explanation of neutron star kicks.

Baryon asymmetry, dark matter, and quantum chromodynamics

We propose a novel scenario to explain the observed cosmological asymmetry between matter and antimatter, based on nonperturbative QCD physics. This scenario relies on a mechanism of separation of quarks and antiquarks in two coexisting phases at the end of the cosmological QCD phase transition: ordinary hadrons (and antihadrons), along with massive lumps (and antilumps) of novel color superconducting phase. The latter would serve as the cosmological cold dark matter. In certain conditions the separation of charge is

Topological currents in neutron stars: kicks, precession, toroidal fields, and magnetic helicity

C

WMAP haze: Directly observing dark matter?

and

Cold dark matter as compact composite objects

CP

Diffuse cosmic gamma rays at 1–20 MeV: a trace of the dark matter?

asymmetric and can leave a net excess of hadrons over antihadrons in the conventional phase, even if the visible universe is globally baryon symmetric

Width of the 511 keV line from the bulge of the galaxy

B=0

Diffuse x-rays: Directly observing dark matter?

. In this case an equal, but negative, overall baryon charge must be hidden in the lumps of novel phase. Because of the small volume occupied by these dense lumps/antilumps of color superconducting phase and the specific features of their interaction with normal matter in hadronic phase, this scenario does not contradict the current phenomenological constrains on presence of antimatter in the visible universe. Moreover, in this scenario the observed cosmological ratio

Bremsstrahlung emission from quark stars

{ensuremath{Omega}}_{mathrm{D}mathrm{M}}ensuremath{sim}{ensuremath{Omega}}_{B}