Abstract: We study the single electron spectra from D- and B-meson semileptonic decays in Au + Au collisions at root s(NN) = 200, 62.4, and 19.2 GeV by employing the parton-hadron-string dynamics (PHSD) transport approach that has been shown to reasonably describe the charm dynamics at Relativistic Heavy Ion Collider and Large Hadron Collider energies on a microscopic level. In this approach the initial charm and bottom quarks are produced by using the PYTHIA event generator which is tuned to reproduce the fixed-order next-to-leading logarithm calculations for charm and bottom production. The produced charm and bottom quarks interact with off-shell (massive) partons in the quark-gluon plasma with scattering cross sections which are calculated in the dynamical quasiparticle model that is matched to reproduce the equation of state of the partonic system above the deconfinement temperature T-c. At energy densities close to the critical energy density (approximate to 0.5 GeV/fm(3)) the charm and bottom quarks are hadronized intoD and B mesons through either coalescence or fragmentation. After hadronization the D and B mesons interact with the light hadrons by employing the scattering cross sections from an effective Lagrangian. The final D and B mesons then produce single electrons through semileptonic decay. We find that the PHSD approach well describes the nuclear modification factor R-AA and elliptic flow upsilon(2) of single electrons in d + Au and Au + Au collisions at root s(NN) = 200 GeV and the elliptic flow in Au + Au reactions at root s(NN) = 62.4 GeV from the PHENIX Collaboration, however, the large RAA at root s(NN) = 62.4 GeV is not described at all. Furthermore, we make predictions for the RAA of D mesons and of single electrons at the lower energy of root s(NN) = 19.2 GeV. Additionally, the medium modification of the azimuthal angle phi between a heavy quark and a heavy antiquark is studied. We find that the transverse flow enhances the azimuthal angular distributions close to phi = 0 because the heavy flavors strongly interact with nuclear medium in relativistic heavy-ion collisions and almost flow with the bulk matter.

Abstract: The goal of the NEXT experiment is the observation of neutrinoless double beta decay in Xe-136 using a gaseous xenon TPC with electroluminescent amplification and specialized photodetector arrays for calorimetry and tracking. The NEXT Collaboration is exploring a number of reconstruction algorithms to exploit the full potential of the detector. This paper describes one of them: the Maximum Likelihood Expectation Maximization (ML-EM) method, a generic iterative algorithm to find maximum-likelihood estimates of parameters that has been applied to solve many different types of complex inverse problems. In particular, we discuss a bi-dimensional version of the method in which the photosensor signals integrated over time are used to reconstruct a transverse projection of the event. First results show that, when applied to detector simulation data, the algorithm achieves nearly optimal energy resolution (better than 0.5% FWHM at the Q value of 136Xe) for events distributed over the full active volume of the TPC.

Abstract: Pseudorapidity and azimuthal three-particle correlations are studied based on a correlated-cluster model of multiparticle production. The model provides a common framework for correlations in proton-proton and heavy-ion collisions allowing easy comparison with the measurements. It is shown that azimuthal cluster correlations are definitely required in order to understand three-particle correlations in the near-side ridge effect. This is similar to the explanation of the ridge phenomenon found in our previous analysis of two-particle correlations and generalizes the model to higher-order correlations.

Abstract: We studied the N*(1875)(3/ 2-) resonance with a multichannel unitary scheme, considering the Delta pi and Sigma * K, with their interaction extracted from chiral Lagrangians, and then added two more channels, the N*(1535) p and N sigma, which proceed via triangle diagrams involving the Sigma * K and Delta pi respectively in the intermediate states. The triangle diagram in the N*(1535) p case develops a singularity at the same energy as the resonance mass. We determined the couplings of the resonance to the different channels and the partial decay widths. We found a very large decay width to Sigma * K, and also observed that, due to interference with other terms, the N sigma channel has an important role in the pi pi mass distributions at low invariant masses, leading to an apparently large N sigma decay width. We discuss justifying the convenience of an experimental reanalysis of this resonance, in light of the findings of the paper, using multichannel unitary schemes.

Abstract: We investigate the eta' photoproduction off the nucleon with a particular interest in the effect of the final-state interaction (FSI) of the eta' meson and nucleon (eta' N) based on the three-flavor linear sigma model. We find an enhancement in the cross section of the eta' photoproduction near the eta' N-threshold energy owing to the eta' N FSI. With the eta' meson at forward angles, the energy dependence near the eta' N threshold is well reproduced with the eta' N FSI. The cross section at backward angles can also be a good probe to investigate the strength of the eta' N interaction.