Single particle inclusive spectra, HBT and elliptic flow; a consistent picture at RHIC?

In these proceedings we will present the preliminary identified single particle inclusive spectra, the identified particle elliptic flow and the HBT versus the reaction plane measured with the STAR detector at RHIC. So far none of the theoretical space-time models has been able to describe the combination of these measurements consistently. In order to see if our measurements can be understood in the context of a simple hydro-motivated blast wave model we extract the relevant parameters for this model, and show that it leads to a consistent description of these observables.Comment: 9 pages, 5 figures (in eps) talk given at XXXI International Symposium on Multiparticle Dynamics, Sep. 1-7, 2001, Datong China URL http://ismd31.ccnu.edu.cn

How much does the hadronic phase contribute to the observed anisotropic flow at the LHC?

Elliptic flow signals the presence of multiple interactions between the constituents of the created matter in heavy-ion collisions. This includes possible contributions from the different phases, including the hadronic phase. In these proceedings I will first show that the energy dependence of elliptic flow, based on recent ALICE and STAR beam energy scan measurements, can largely be understood in terms of a boosted thermal system. In addition, a detailed comparison between the identified particle elliptic flow measured by the ALICE collaboration and viscous hydrodynamical model calculations with and without a hadronic afterburner is performed to constrain the possible effects of individual hadron-hadron re-interaction cross-sections.Comment: 10 pages, 8 figures, proceedings Resonance Workshop at Catania, version two updated with referee comment

Heavy Ion Collisions

Lattice QCD predicts a phase transition between hadronic matter and a system of deconfined quarks and gluons (the Quark Gluon Plasma) at high energy densities. Recent results from the Brookhaven Relativistic Heavy Ion Collider (RHIC) dedicated to the study of QCD at extreme densities will be discussed and compared to measurements obtained at the CERN Super Proton Synchrotron (SPS).Comment: Invited talk at the XXIII Physics in Collisions Conference (PIC03), Zeuthen, Germany, June 2003, 14 pages, LaTeX, 13 eps figures. PSN SAAT0

Collective Expansion at the LHC: selected ALICE anisotropic flow measurements

The collective expansion of matter created in collisions of heavy-ions, ranging from collision energies of tens of MeV to a few TeV per nucleon pair, proved to be one of the best probes to study the detailed properties of these unknown states of matter. Collective expansion originates from the initial pressure gradients in the created hot and dense matter. These pressure gradients transform the initial spatial deformations and inhomogeneities of the created matter into momentum anisotropies of the final state particle production, which we call anisotropic flow. These momentum anisotropies are experimentally characterised by so-called flow harmonics. In this paper I review ALICE measurements of the flow harmonics at the CERN Large Hadron Collider and discuss some of the open questions.Comment: 25 pages, 15 figures, invited review for J. Phys. G Focus Issue on "Collective flow and transport phenomena in heavy ion physics" Edited by Takeshi Kodama, Nu Xu and Horst Stoecke

Institutional investors in Germany : insurance companies and investment funds

This chapter focuses on institutional investors in the German financial markets. Institutional investors are specialized financial intermediaries who collect and manage funds on behalf of small investors toward specific objectives in terms of risk, return and maturity. The major types of institutional investors in Germany are insurance companies and investment funds. We will examine the nature of their businesses, their size and role in the financial sector, the size and the composition of the assets under their management, aspects of financ ial regulation, and features of their asset-liability-management

Portfolio choice and estimation risk : a comparison of Bayesian approaches to resampled efficiency

Estimation risk is known to have a huge impact on mean/variance (MV) optimized portfolios, which is one of the primary reasons to make standard Markowitz optimization unfeasible in practice. Several approaches to incorporate estimation risk into portfolio selection are suggested in the earlier literature. These papers regularly discuss heuristic approaches (e.g., placing restrictions on portfolio weights) and Bayesian estimators. Among the Bayesian class of estimators, we will focus in this paper on the Bayes/Stein estimator developed by Jorion (1985, 1986), which is probably the most popular estimator. We will show that optimal portfolios based on the Bayes/Stein estimator correspond to portfolios on the original mean-variance efficient frontier with a higher risk aversion. We quantify this increase in risk aversion. Furthermore, we review a relatively new approach introduced by Michaud (1998), resampling efficiency. Michaud argues that the limitations of MV efficiency in practice generally derive from a lack of statistical understanding of MV optimization. He advocates a statistical view of MV optimization that leads to new procedures that can reduce estimation risk. Resampling efficiency has been contrasted to standard Markowitz portfolios until now, but not to other approaches which explicitly incorporate estimation risk. This paper attempts to fill this gap. Optimal portfolios based on the Bayes/Stein estimator and resampling efficiency are compared in an empirical out-of-sample study in terms of their Sharpe ratio and in terms of stochastic dominance

Proof that it is not always optimal to locate bonds in a tax-deferred account

The tax codes in many countries allow for special tax advantages for investments in special retirement plans. Probably the most important advantage to these plans is that profits usually remain untaxed. This paper deals with the question, which assets are preferable in a taxdeferred account (TDA). Contrary to the conventional wisdom that one should prefer bonds in the TDA, it is shown that especially in early years, stocks can be the preferred asset to hold in the TDA for an investor maximizing final wealth, given a certain asset allocation. The higher the performance of stocks compared to bonds, the higher the tax burden put on stocks compared to bonds. Simultaneously, the longer the remaining investment horizon, the larger the relative outperformance of the optimal asset location strategy compared to the myopic strategy of locating bonds in the TDA. An algorithm is provided to determine the investment strategy that maximizes (expected) funds at the end of a given investment horizon when there is an analytical solution

Does size matter? : Economies of scale in the German mutual fund industry

In this paper, we analyze economies of scale for German mutual fund complexes. Using 2002-2005 data of 41 investment management companies, we specify a hedonic translog cost function. Applying a fixed effects regression on a one-way error component model there is clear evidence of significant overall economies of scale. On the level of individual mutual fund complexes we find significant economies of scale for all of the companies in our sample. With regard to cost efficiency, we find that the average mutual fund complexes in all size quartiles deviate considerably from the best practice cost frontier. JEL Classification: G2, L25 Keywords: mutual fund complex, investment management company, cost efficiency, economies of scale, hedonic translog cost function, fixed effects regression, one-way error component mode

How unobservable bond positions in retirement accounts affect asset allocation

Many tax-codes around the world allow for special taxable treatment of savings in retirement accounts. In particular, profits in retirement accounts are usually tax exempt which allow investors to increase an asset’s return by holding it in such a retirement account. While the existing literature on asset location shows that risk-free bonds are usually the preferred asset to hold in a retirement account, we explain how the tax exemption of profits in retirement accounts affects private investors’ asset allocation. We show that total final wealth can be decomposed into what the investor would have earned in a taxable account and what is due to the tax exemption of profits in the retirement account. The tax exemption of profits can thus be considered a tax-gift which is similar to an implicit bond holding. As this tax-gift’s impact on total final wealth decreases over time, so does the investor’s equity exposure