Negative Elliptic Flow from Anomaly Induced DCC Formation

We discuss characteristic experimental signatures related to the mechanism of DCC formation triggered by the chiral U(1) anomaly in relativistic heavy ion collisions. We predict an enhancement of the fraction of neutral pions compared with all pions in the direction perpendicular to the scattering plane. To quantify the effect on the angular distribution of neutral pions, we compute the elliptic flow parameter $v_2$ as a function of the transverse momentum. We find values of order -0.05 at small momenta for neutral pions. We also compute the $v_2$ parameter for inclusive photons, which is easier to measure, and confirmed that the negative a few percent effect prevails in this observable.Comment: Contribution to PANIC 200

Fluctuation Probes of Quark Deconfinement

The size of the average fluctuations of net baryon number and electric charge in a finite volume of hadronic matter differs widely between the confined and deconfined phases. These differences may be exploited as indicators of the formation of a quark-gluon plasma in relativistic heavy-ion collisions, because fluctuations created in the initial state survive until freeze-out due to the rapid expansion of the hot fireball.Comment: 4 pages RevTeX, 1 figure; submitted simultaneously with hep-ph/0003168. Relative to v2 a typo was corrected, and the "Note added" was expanded by a clarifying sentence. This version accepted by Physical Review Letter

Third moments of conserved charges in QCD phase diagram

We point out that the third moments of conserved charges, the baryon and electric charge numbers, and energy, as well as their mixed moments, change their signs around the QCD phase boundary in the temperature and baryon chemical potential plane. These signs can be measured in relativistic heavy ion collisions, and will give clear information on the phase structure of QCD and the state of the system in the early stage of relativistic heavy ion collisions. The behaviors of these moments on the temperature axis and at small quark chemical potential can be analyzed in lattice QCD simulations. We emphasize that the third moments obtained on the lattice, together with the experimental results, will provide a deep understanding about the QCD phase diagram and the location of the state created in heavy ion collisions.Comment: 7 pages, 2 figures, Contribution to the "XXVII International Symposium on Lattice Field Theory", July 26-31, 2009, Peking University, Beijing, Chin

Nonequilibrium time evolution of higher order cumulants of conserved charges and event-by-event analysis

We investigate the time evolution of higher order cumulants of conserved charges in a volume with the diffusion master equation. Applying the result to the diffusion of non-Gaussian fluctuations in the hadronic stage of relativistic heavy ion collisions, we show that the fourth-order cumulant of net-electric charge at LHC energy is suppressed compared with the recently observed second-order cumulant at ALICE, if the higher order cumulants at hadronization are suppressed compared with their values in the hadron phase in equilibrium. The significance of the experimental information on the rapidity window dependence of various cumulants in investigating the history of the dynamical evolution of the hot medium created in relativistic heavy ion collisions is emphasized.Comment: 8 pages, 3 figure

Third moments of conserved charges as probes of QCD phase structure

The third moments of conserved charges, the baryon and electric charge numbers, and energy, as well as their mixed moments, carry more information on the state around the QCD phase boundary than previously proposed fluctuation observables and higher order moments. In particular, their signs give plenty of information on the location of the state created in relativistic heavy ion collisions in the temperature and baryon chemical potential plane. We demonstrate this with an effective model.Comment: 4 pages, 2 figures. Minor changes. To be published in Physical Review Letter

Electric Charge Separation in Strong Transient Magnetic Fields

We discuss various mechanisms for the creation of an asymmetric charge fluctuation with respect to the reaction plane among hadrons emitted in relativistic heavy-ion collisions. We show that such mechanisms exist in both, the hadronic gas and the partonic phases of QCD. The mechanisms considered here all require the presence of a strong magnetic field (the ``chiral magnetic effect''), but they do not involve parity or charge-parity violations. We analyze how a transient local electric current fluctuation generated by the chiral magnetic effect can dynamically evolve into an asymmetric charge distribution among the final-state hadrons in momentum space. We estimate the magnitude of the event-by-event fluctuations of the final-state charge asymmetry due to the partonic and hadronic mechanisms