Angular Dependence of Jet Quenching Indicates Its Strong Enhancement Near the QCD Phase Transition

We study dependence of jet quenching on matter density, using "tomography" of the fireball provided by RHIC data on azimuthal anisotropy $v_2$ of high $p_t$ hadron yield at different centralities. Slicing the fireball into shells with constant (entropy) density, we derive a "layer-wise geometrical limit" $v_2^{max}$ which is indeed above the data $v_2<v_2^{max}$. Interestingly, the limit is reached only if quenching is dominated by shells with the entropy density exactly in the near-$T_c$ region. We show two models that simultaneously describe the high $p_t$ $v_2$ and $R_{AA}$ data and conclude that such a description can be achieved only if the jet quenching is few times stronger in the near-$T_c$ region relative to QGP at $T>T_c$. One possible reason for that may be recent indications that the near-$T_c$ region is a magnetic plasma of relatively light color-magnetic monopoles.Comment: 4 pages, 4 figures. Final version published as PRL102,202302(2009

Increase of gluthatione S-transferase, carboxyl esterase and carbonyl reductase in Fasciola hepatica recovered from triclabendazole treated sheep

Fasciolasis is a zoonotic parasitic disease caused by Fasciola hepatica and its control is mainly based on the use of triclabendazole (TCBZ). Parasite resistance to different anthelmintics is growing worldwide, including the resistance of F. hepatica to TCBZ. In the present work we evaluate “in vivo” the activity of xenobiotic metabolizing enzymes of phase I (carboxyl esterases) and phase II (glutathione S-transferases and carbonyl reductases) recovered of flukes from sheep treated with TCBZ. All three enzymes showed increased activity in TCBZ flukes returning 60 h post-treatment at similar to baseline unexposed flukes. TCBZ action may induce secondary oxidative stress, which may explain the observed increment in activities of the analyzed enzymes as a defensive mechanism. The enzymes analyzed are candidates to participate actively in the development of resistance at TCBZ in F. hepatica.Fil: Scarcella, Silvana Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tandil. Centro de Investigacion Veterinaria de Tandil; ArgentinaFil: Solana, M. V.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tandil. Centro de Investigacion Veterinaria de Tandil; ArgentinaFil: Fernandez, Vanesa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tandil. Centro de Investigacion Veterinaria de Tandil; ArgentinaFil: Lamenza, Pamela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tandil. Centro de Investigacion Veterinaria de Tandil; ArgentinaFil: Ceballos, Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tandil. Centro de Investigacion Veterinaria de Tandil; ArgentinaFil: Solana, Hugo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tandil. Centro de Investigacion Veterinaria de Tandil; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; Argentin

S-Wave Quarkonia in Potential Models

We discuss S-wave quarkonia correlators and spectral function using the Wong-potential, and show that these do not agree with the lattice results.Comment: based on talk presented at Strangeness in Quark Matter, UCLA, March 26-31, 200

Probing Color Response - Wakes in a Color Plasma

The wake induced in a hot QCD medium by a high momentum parton (jet precursor) is calculated in the framework of linear response theory. Two different scenarios are discussed: a weakly coupled quark gluon plasma (pQGP) as described by hard-thermal loop (HTL) perturbation theory and a strongly cupled QGP (sQGP) with the properties of a quantum liquid. In the latter case the wake could exhibit a pronounced Mach cone structure. This physical mechanism could be important for the understanding of preliminary data from the PHENIX and STAR experiments at RHIC on the angular distribution of low-pt secondaries stemming from the away-side jet which indicate maxima at $\Delta\phi=\pi \pm 1.1$.Comment: Prepared for: Workshop on Correlations and Fluctuations in Relativistic Nuclear Collisions, MIT, Cambridge, Massachusetts, USA, 21-23 April 200

Mach Cones in Quark Gluon Plasma

The experimental azimuthal dihadron distributions at RHIC show a double peak structure in the away side ($\Delta \phi = \pi \pm 1.2$ rad.) for intermediate $p_t$ particles. A variety of models have appeared trying to describe this modification. We will review most of them, with special emphasis in the Conical Flow scenario in which the observed shape is a consequence of the emission of sound by a supersonic high momentum particle propagating in the Quark Gluon Plasma.Comment: 8 pages, 3 figures, Invited plenary talk given at the 19th International Conference on Ultrarelativistic Nucleus-Nucleus Collisions: Quark Matter 2006 (QM 2006), Shanghai, China, 14-20 Nov 200

Elliptic flow in proton-proton collisions at 7 TeV

The angular correlations measured in proton-proton collisions at 7 TeV are decomposed into contributions from back to back emission and elliptic flow. Modeling the dominant term in the correlation functions as a momentum conservation effect or as an effect of the initial transverse velocity of the source, the remaining elliptic flow component can be estimated. The elliptic flow coefficient extracted from the CMS Collaboration data is 0.04-0.08. No additional small-angle, ridge-like correlations are needed to explain the experimental data