Hadronization via Coalescence

We review the quark coalescence model for hadronization in relativistic heavy ion collisions and show how it can explain the observed large baryon to meson ratio at intermediate transverse momentum and scaling of the elliptic flows of identified hadrons. We also show its predictions on higher-order anisotropic flows and discuss how quark coalescence applied to open- and hidden-charm mesons can give insight to charm quark interactions in the quark-gluon plasma and $J/\Psi$ production in heavy ion collisions.Comment: 6 pages, 4 figures, Proceedings of 20th Winter Workshop on Nuclear Dynamics, Trelawny Beach, Jamaica, March 15--20, 200

Safe discontinuation of nilotinib in a patient with chronic myeloid leukemia: a case report

Case presentation. We report the case of a 64-year-old Caucasian man diagnosed with chronic-phase chronic myeloid leukemia in April 2005. After 4 years of treatment with imatinib, he became intolerant to the drug and was switched to nilotinib. Two years later, he decided to stop nilotinib. Undetectable molecular response persisted for 30 months after discontinuation of the drug. Introduction. Although there is a considerable amount of data in the literature on safe discontinuation of first-generation tyrosine kinase inhibitor therapy in patients with chronic myeloid leukemia, little is known about discontinuation of second-generation tyrosine kinase inhibitor therapy. Most previous studies have been focused on dasatinib, and the few cases of nilotinib withdrawal that have been reported had a median follow-up of 12 months. To the best of our knowledge, the present report is the first to describe nilotinib withdrawal with 30 months of follow-up. Conclusion: Our present case suggests that nilotinib withdrawal is safe for patients with chronic myeloid leukemia who achieve a stable undetectable molecular response. Our patient was homozygous for killer immunoglobulin-like receptor haplotype A, previously reported to be a promising immunogenetic marker for undetectable molecular response. We recommend additional studies to investigate patient immunogenetic profiles and their potential role in complete response to therap

Transport properties of isospin effective mass splitting

We investigate in detail the momentum dependence ($MD$) of the effective in medium Nucleon-Nucleon ($NN$) interaction in the isovector channel. We focus the discussion on transport properties of the expected neutron-proton ($n/p$) effective mass splitting at high isospin density. We look at observable effects from collective flows in Heavy Ion Collisions ($HIC$) of charge asymmetric nuclei at intermediate energies. Using microscopic kinetic equation simulations nucleon transverse and elliptic collective flows in $Au+Au$ collisions are evaluated. In spite of the reduced charge asymmetry of the interacting system interesting $isospin-MD$ effects are revealed. Good observables, particularly sensitive to the $n/p$-mass splitting, appear to be the differences between neutron and proton flows. The importance of more exclusive measurements, with a selection of different bins of the transverse momenta ($p_t$) of the emitted particles, is stressed. In more inclusive data a compensation can be expected from different $p_t$-contributions, due to the microscopic $isospin-MD$ structure of the nuclear mean field in asymmetric matter.Comment: 18 pages, 11 figure

Scalings of Elliptic Flow for a Fluid at Finite Shear Viscosity

Within a parton cascade approach we investigate the scaling of the differential elliptic flow $v_2(p_T)$ with eccentricity $\epsilon_x$ and system size and its sensitivity to finite shear viscosity. We present calculations for shear viscosity to entropy density ratio $\eta/s$ in the range from $1/4\pi$ up to $1/\pi$, finding that the $v_2$ saturation value varies by about a factor 2. Scaling of $v_2(p_T)/\epsilon_x$ is seen also for finite $\eta/s$ which indicates that it does not prove a perfect hydrodynamical behavior, but is compatible with a plasma at finite $\eta/s$. Introducing a suitable freeze-out condition, we see a significant reduction of $v_2(p_T)$ especially at intermediate $p_T$ and for more peripheral collisions. This causes a breaking of the scaling for both $v_2(p_T)$ and the $p_T-$averaged $v_2$, while keeping the scaling of v_2(p_T)/\la v_2\ra. This is in better agreement with the experimental observations and shows as a first indication that the $\eta/s$ should be significantly lower than the pQCD estimates. We finally point out the necessity to include the hadronization via coalescence for a definite evaluation of $\eta/s$ from intermediate $p_T$ data.Comment: 5 pages, 5 figures. Two points in fig.4 has been change

Impact of temperature dependence of the energy loss on jet quenching observables

The quenching of jets (particles with $p_T>>T, \Lambda_{QCD}$) in ultra-relativistic heavy-ion collisions has been one of the main prediction and discovery at RHIC. We have studied, by a simple jet quenching modeling, the correlation between different observables like the nuclear modification factor \Rapt, the elliptic flow $v_2$ and the ratio of quark to gluon suppression $R_{AA}(quark)/R_{AA}(gluon)$. We show that the relation among these observables is strongly affected by the temperature dependence of the energy loss. In particular the large $v_2$ and and the nearly equal \Rapt of quarks and gluons can be accounted for only if the energy loss occurs mainly around the temperature $T_c$ and the flavour conversion is significant.Finally we point out that the efficency in the conversion of the space eccentricity into the momentum one ($v_2$) results to be quite smaller respect to the one coming from elastic scatterings in a fluid with a viscosity to entropy density ratio $4\pi\eta/s=1$.Comment: 7 pages, 8 figures, Workshop WISH 201

Probing the Nuclear Symmetry Energy with Heavy Ion Collisions

Heavy Ion Collisions (HIC) represent a unique tool to probe the in-medium nuclear interaction in regions away from saturation. In this report we present a selection of new reaction observables in dissipative collisions particularly sensitive to the symmetry term of the nuclear Equation of State ($Iso-EoS$). We will first discuss the Isospin Equilibration Dynamics. At low energies this manifests via the recently observed Dynamical Dipole Radiation, due to a collective neutron-proton oscillation with the symmetry term acting as a restoring force. At higher beam energies Iso-EoS effects will be seen in an Isospin Diffusion mechanism, via Imbalance Ratio Measurements, in particular from correlations to the total kinetic energy loss. For fragmentation reactions in central events we suggest to look at the coupling between isospin distillation and radial flow. In Neck Fragmentation reactions important Iso-EoS information can be obtained from fragment isospin content, velocity and alignement correlations. The high density symmetry term can be probed from isospin effects on heavy ion reactions at relativistic energies (few AGeV range), in particular for high transverse momentum selections of the reaction products. Rather isospin sensitive observables are proposed from nucleon/cluster emissions, collective flows and meson production. The possibility to shed light on the controversial neutron/proton effective mass splitting in asymmetric matter is also suggested. A large symmetry repulsion at high baryon density will also lead to an "earlier" hadron-deconfinement transition in n-rich matter. The binodal transition line of the (T,\rho_B) diagram is lowered to a region accessible through heavy ion collisions in the energy range of the new planned facilities, e.g. the FAIR/NICA projects. Some observable effects of the formation of a Mixed Phase are suggested, in particular a Neutron Trapping mechanism. The dependence of the results on a suitable treatment of the isovector part of the interaction in effective QCD Lagrangian approaches is critically discussed. We stress the interest of this study in nuclear astrophysics, in particular for supernovae explosions and neutron star structure, where the knowledge of the Iso-EoS is important at low as well as at high baryon density.Comment: 52 pages, 28 figures, topical review submitted to J. Phys. G: Nucl. Phys (IOP Latex