Production, elliptic flow and energy loss of heavy quarks in the quark-gluon plasma

Production, elliptic flow and the nuclear modification factor of charm and bottom quarks are studied in central and non-central heavy-ion collisions at RHIC and LHC using the partonic transport model Boltzmann Approach of MultiParton Scatterings (BAMPS). Employing an initial heavy quark yield obtained with PYTHIA the full space-time evolution of charm and bottom quarks in the quark-gluon plasma (QGP) is carried out with BAMPS, taking also secondary production in the QGP into account. Only elastic collisions of heavy quarks with particles from the medium cannot describe the experimentally observed elliptic flow and nuclear modification factor. However, using an improved Debye screening and the running coupling yields a result which is much closer to data.Comment: 4 pages, 1 figure, to appear in the conference proceedings of Hot Quarks 2010, few minor modifications in 2nd versio

Heavy quark production at RHIC and LHC within a partonic transport model

The production and space-time evolution of charm and bottom quarks in nucleus-nucleus collisions at RHIC and LHC are investigated with the partonic transport model BAMPS (Boltzmann Approach of MultiParton Scatterings). Heavy quarks, produced in primary hard parton scatterings during nucleon-nucleon collisions, are sampled using the Monte Carlo event generator PYTHIA or the leading order mini-jet model in conjunction with the Glauber model, revealing a strong sensitivity on the parton distribution functions, scales, and heavy quark mass. In a comprehensive study exploring different charm masses, K factors, and possible initial gluon conditions, secondary production and the evolution of heavy quarks are examined within a fully dynamic BAMPS simulation for central heavy ion collisions at RHIC and LHC. Although charm production in the quark-gluon plasma can be neglected at RHIC, it is significant at LHC but very sensitive to the initial conditions and the charm mass. Bottom production in the quark-gluon plasma, however, is negligible both at RHIC and LHC.Comment: 47 pages, 22 figures, and 8 tables, version accepted for publication in PRC, minor modifications of text and figure

Radio astronomy Explorer-B in-flight mission control system development effort

A description is given of the development for the Mission Analysis Evaluation and Space Trajectory Operations (MAESTRO) program to be used for the in-flight decision making process during the translunar and lunar orbit adjustment phases of the flight of the Radio Astronomy Explorer-B. THe program serves two functions: performance and evaluation of preflight mission analysis, and in-flight support for the midcourse and lunar insertion command decisions that must be made by the flight director. The topics discussed include: analysis of program and midcourse guidance capabilities; methods for on-line control; printed displays of the MAESTRO program; and in-flight operational logistics and testing

Jet quenching and elliptic flow at RHIC and LHC within a pQCD-based partonic transport model

Fully dynamic simulations of heavy ion collisions at RHIC and at LHC energies within the perturbative QCD-based partonic transport model BAMPS (Boltzmann Approach to Multi-Parton Scatterings) are presented, focusing on the simultaneous investigation of jet quenching and elliptic flow. The model features inelastic 2 3 processes based on the Gunion-Bertsch matrix element and has recently been extended to include light quark degrees of freedom, allowing for direct comparison to hadronic data on the nuclear modification factor via a fragmentation scheme for high-pT partons. The nuclear modification factor of neutral pions in central Au+Au collisions at RHIC energy is compared to experimental data. Furthermore first results on the nuclear modification factor and the integrated elliptic flow of charged hadrons in Pb+Pb collisions at LHC are presented and compared to recent ALICE data. These investigations are complemented by a study on the suppression of D-mesons at LHC based on elastic interactions with the medium.Comment: To appear in the proceedings of Quark Matter 201

Viscous Effects on Elliptic Flow and Shock Waves

Fast thermalization and a strong buildup of elliptic flow of QCD matter as found at RHIC are understood as the consequence of perturbative QCD (pQCD) interactions within the 3+1 dimensional parton cascade BAMPS. The main contributions stem from pQCD bremsstrahlung $2 \leftrightarrow 3$ processes. By comparing to Au+Au data of the flow parameter $v_2$ as a function of participation number the shear viscosity to entropy ratio is dynamically extracted, which lies in the range of 0.08 and 0.2, depending on the chosen coupling constant and freeze out condition. Furthermore, first simulations on the temporal propagation of dissipative shock waves are given. The cascade can either simulate true ideal shocks as well as initially diluted, truely viscous shocks, depending on the employed cross sections or mean free path, respectively.Comment: 7 pages, 8 figures, to appear in the proceedings of the 2008 Erice School on Nuclear Physics, Sicil

What Do I Do with the Porn on My Computer: How a Lawyer Should Counsel Clients about Physical Evidence

For years, criminal defense lawyers and commentators have wrestled with thorny ethical and legal issues surrounding defense counsel\u27s obligations with respect to handling items of physical evidence. Commentators have usually focused on the question of whether the lawyer should take possession of physical evidence of a crime as well as on counsel\u27s obligations and options once the lawyer purposively or inadvertently comes into possession of such evidence. After discussing what the ethics rules and the law require concerning handling physical evidence, commentators have generally cautioned lawyers not to take possession of suspected contraband or possible evidence of a crime, except in very limited situations, such as when the evidence may aid in the client\u27s defense or its evidentiary value is ambiguous without further examination or testing of it. Rarely, however, is much attention devoted to the issue of what advice the lawyer should give the client if the lawyer declines to take possession of the physical evidenc

Systemic Barriers to Effective Assistance of Counsel in Plea Bargaining

In a trio of recent cases, Padilla v. Kentucky, Missouri v. Frye, and Lafler v. Cooper, the U.S. Supreme Court has focused its attention on defense counsel\u27s pivotal role during the plea bargaining process . At the same time that the Court has signaled its willingness to consider ineffective assistance of counsel claims at the plea stage, prosecutors are increasingly requiring defendants to sign waivers that include waiving all constitutional and procedural errors, even unknown ineffective assistance of counsel claims such as those that proved successful in Padilla and Frye. Had Jose Padilla and Galin Frye been forced to sign a waiver of any ineffective assistance of counsel claim as a condition of entering their pleas, and if the Supreme Court approved of such waivers, then neither Padilla nor Frye would have secured the relief the Court held that they deserved. Waivers of ineffective assistance of counsel claims pose both legal and ethical issues. Legally, the waivers serve to undermine a defendant’s due process rights — recognized by the Court in Gideon v. Wainwright — by requiring the defendant not only to waive what is unknown to them at the time of waiver, but to do so even when based upon bad advice of ineffective counsel. Ethically, a defense lawyer counseling a defendant to waive ineffective assistance of counsel claims has a personal conflict of interest with the client, because the lawyer has reputational and other interests in not having the lawyer’s representation of the client determined to be ineffective.Whether the Supreme Court would approve a waiver of an ineffective assistance claim that would negate the due process right to effective assistance of counsel is not yet resolved. Such a decision, however, would immunize much incompetent lawyering from any judicial scrutiny altogether.This article begins by examining the systemic barriers defense counsel face to provide meaningful advice to criminal defendants contemplating a guilty plea These barriers include the underfunding of defense services in many jurisdictions and the coerciveness of the plea bargaining process. Next, the article analyzes the law and ethics of waivers of ineffective assistance of counsel claims and whether such waivers should be permissible. We contend that such waivers should not be enforceable for both legal and ethical reasons. Permitting waivers of ineffective assistance of counsel claims not only constitutes judicial acceptance of a prosecutorial veto of the Court’s recent decisions regarding plea bargaining, but also ensures that more defendants never receive the effective assistance of counsel during plea bargaining

Collective Flow and Mach Cones with Parton Transport

Fast thermalization and a strong build up of elliptic flow of QCD matter were investigated within the pQCD based 3+1 dimensional parton transport model BAMPS including bremsstrahlung $2 \leftrightarrow 3$ processes. Within the same framework quenching of gluonic jets in Au+Au collisions at RHIC can be understood. The development of conical structure by gluonic jets is investigated in a static box for the regimes of small and large dissipation. Furthermore we demonstrate two different approaches to extract the shear viscosity coefficient $\eta$ from a microscopical picture.Comment: 7 pages, 8 figures, 1 table; to appear in the proceedings of Hot and Cold Baryonic Matter -- HCBM 201

Collective Flow and Energy Loss with parton transport

Quenching of gluonic jets and heavy quark production in Au+Au collisions at RHIC can be understood within the pQCD based 3+1 dimensional parton transport model BAMPS including pQCD bremsstrahlung $2 \leftrightarrow 3$ processes. Furthermore, the development of conical structures induced by gluonic jets is investigated in a static box for the regimes of small and large dissipation.Comment: typos corrected, figure labels enlarged; Talk given by C. Greiner; to appear in the proceedings of WISH201