Baryon anomaly and strong color fields in Pb+Pb collisions at 2.76A TeV at the CERN Large Hadron Collider

With the HIJING/BBbar v2.0 heavy ion event generator, we explore the phenomenological consequences of several high parton density dynamical effects predicted in central Pb+Pb collisions at the Large Hadron Collider (LHC) energies. These include (1) jet quenching due to parton energy loss (dE/dx), (2) strangeness and hyperon enhancement due to strong longitudinal color field (SCF), and (3) enhancement of baryon-to-meson ratios due to baryon-anti-baryon junctions (JJbar) loops and SCF effects. The saturation/minijet cutoff scale p0(s)and effective string tension kappa(s,A) are constrained by our previous analysis of LHC p+p data and recent data on the charged multiplicity for Pb+Pb collisions reported by the ALICE collaboration. We predict the hadron flavor dependence (mesons and baryons) of the nuclear modification factor RAA(pT)$ and emphasize the possibility that the baryon anomaly could persist at the LHC up to pT=10 GeV, well beyond the range observed in central Au+Au collisions at RHIC energies.Comment: 25 pages, 8 figures, revtex4, text modifications, added references, accepted for publication Phys. Rev. C (2011

Soft Open Charm Production in Heavy-Ion Collisions

Effects of strong longitudinal color electric fields (SCF) on the open charm production in nucleus-nucleus (A + A) collisions at 200A GeV are investigated within the framework of the HIJING-BBbar v2.0 model. A three fold increase of the effective string tension due to in medium effects in A + A collisions, results in a sizeable (60-70 percents) enhancement of the total charm production cross sections. The nuclear modification factors show a suppression at moderate transverse momentum consistent with RHIC data. At Large Hadron Collider energies the model predicts an increase of total charm production cross sections by approximately an order of magnitude.Comment: 5 pages, 3 figures, submitted to Phys. Rev. Let

Predicting Financial Distress in a High-Stress Financial World: The Role of Option Prices as Bank Risk Metrics

The current financial crisis offers a unique opportunity to investigate the leading properties of market indicators in a stressed environment and their usefulness from a banking supervision perspective. One pool of relevant information that has been little explored in the empirical literature is the market for bank’s exchange-traded option contracts. In this paper, we first extract implied volatility indicators from the prices of the most actively traded option contracts on financial firms’ equity. We then examine empirically their ability to predict financial distress by applying survival analysis techniques to a sample of large US financial firms. We find that market indicators extracted from option prices significantly explain the survival time of troubled financial firms and do a better job in predicting financial distress than other time-varying covariates typically included in bank failure models. Overall, both accounting information and option prices contain useful information of subsequent financial problems and, more importantly, the combination produces good forecasts in a high-stress financial world, full of doubts and uncertainties.Financial distress; Financial system oversight; Market discipline; Options; Implied volatility; Survival analysis.

Two-way interplays between capital buffers, credit and output: evidence from French banks

We assess the extent to which capital buffers (the capital banks hold in excess of the regulatory minimum) exacerbate rather than reduce the cyclical behavior of credit. We empirically study the relationships between output gap, capital buffers and loan growth with firm-level data for French banks over the period 1993—2009. Our findings reveal that bank capital buffers intensify the cyclical credit fluctuations arising from the output gap developments, all the more as better quality capital is considered. Moreover, by performing Granger causality tests at the bank level, we find evidence of a two-way causality between capital buffers and loan growth, pointing to mutually reinforcing mechanisms. Overall, those empirical results lend support to a countercyclical financial regulation that focuses on highest-quality capital and aims at smoothing loan growth.Bank Capital Regulation, Procyclicality, Capital Buffers, Business Cycle Fluctuations, Basel III.

Interference in interacting quantum dots with spin

We study spectral and transport properties of interacting quantum dots with spin. Two particular model systems are investigated: Lateral multilevel and two parallel quantum dots. In both cases different paths through the system can give rise to interference. We demonstrate that this strengthens the multilevel Kondo effect for which a simple two-stage mechanism is proposed. In parallel dots we show under which conditions the peak of an interference-induced orbital Kondo effect can be split.Comment: 8 pages, 8 figure