Bequests and heterogeneity in retirement wealth

Households hold vastly heterogeneous amounts of wealth when they reach retirement, and differences in lifetime earnings explain only part of this variation. This paper studies the role of intergenerational transmission of ability, voluntary bequest motives, and the recipiency of accidental and intended bequests (both in terms of timing and size) in generating wealth dispersion at retirement, in the context of a rich quantitative model. Modeling voluntary bequests, and realistically calibrating them, not only generates more wealth dispersion at retirement and reduces the correlation between retirement wealth and lifetime income, but also generates a skewed bequest distribution that is close to the one in the observed data

Wealth inequality, family background, and estate taxation

This paper generates two main contributions. First, it provides a new theory of wealth inequality that merges two empirically relevant forces generating inequality: bequest motives and inheritance of ability across generations; and an earnings process that allows for more earnings risk for the richest. Second, it uses the resulting calibrated framework to study the effects of changing estate taxation. Increasing the estate tax reduces the wealth concentration in the hands of the richest few and the economic advantage of being born to a rich and super-rich family at the cost of reduced aggregate capital and output. However, all of these effects are quite small. In contrast, increasing estate taxation can generate a significant welfare gain to a newborn under the veil of ignorance, but this comes at a large welfare cost for the super-rich

Heavy flavours in heavy-ion collisions: quenching, flow and correlations

We present results for the quenching, elliptic flow and azimuthal correlations of heavy flavour particles in high-energy nucleus-nucleus collisions obtained through the POWLANG transport setup, developed in the past to study the propagation of heavy quarks in the Quark-Gluon Plasma and here extended to include a modeling of their hadronization in the presence of a medium. Hadronization is described as occurring via the fragmentation of strings with endpoints given by the heavy (anti-)quark Q(Qbar) and a thermal parton qbar(q) from the medium. The flow of the light quarks is shown to affect significantly the R_AA and v_2 of the final D mesons, leading to a better agreement with the experimental data. The approach allows also predictions for the angular correlation between heavy-flavour hadrons (or their decay electrons) and the charged particles produced in the fragmentation of the heavy-quark strings

Heavy flavours in AA collisions: production, transport and final spectra

A multi-step setup for heavy-flavour studies in high-energy nucleus-nucleus (AA) collisions --- addressing within a comprehensive framework the initial Q-Qbar production, the propagation in the hot medium until decoupling and the final hadronization and decays --- is presented. The initial hard production of Q-Qbar pairs is simulated using the POWHEG pQCD event generator, interfaced with the PYTHIA parton shower. Outcomes of the calculations are compared to experimental data in pp collisions and are used as a validated benchmark for the study of medium effects. In the AA case, the propagation of the heavy quarks in the medium is described in a framework provided by the relativistic Langevin equation. For the latter, different choices of transport coefficients are explored (either provided by a perturbative calculation or extracted from lattice-QCD simulations) and the corresponding numerical results are compared to experimental data from RHIC and the LHC. In particular, outcomes for the nuclear modification factor R_AA and for the elliptic flow v_2 of D/B mesons, heavy-flavour electrons and non-prompt J/\psi's are displayed.Comment: 16 pages, 21 figure

Study of flavour dependencies in leptogenesis

We study the impact of flavours on the efficiency factors and give analytical and numerical results of the baryon asymmetry taking into account the different charged lepton Yukawa contributions and the complete (diagonal and off-diagonal) $L$ to $B-L$ conversion $A$ matrix. With this treatment we update the lower bound on the lightest right-handed neutrino mass.Comment: 13 pages, 11 figures. typos corrected, some formulae modified. 2 figures and discussion adde

Event-shape engineering and heavy-flavour observables in relativistic heavy-ion collisions

Traditionally, events collected at relativistic heavy-ion colliders are classified according to some centrality estimator (e.g. the number of produced charged particles) related to the initial energy density and volume of the system. In a naive picture the latter are directly related to the impact parameter of the two nuclei, which sets also the initial eccentricity of the system: zero in the case of the most central events and getting larger for more peripheral collisions. A more realistic modelling requires to take into account event-by-event fluctuations, in particular in the nucleon positions within the colliding nuclei: collisions belonging to the same centrality class can give rise to systems with different initial eccentricity and hence different flow harmonics for the final hadron distributions. This issue can be addressed by an event-shape-engineering analysis, consisting in selecting events with the same centrality but different magnitude of the average bulk anisotropic flow and therefore of the initial-state eccentricity. In this paper we present the implementation of this analysis in the POWLANG transport model, providing predictions for the transverse-momentum and angular distributions of charm and beauty hadrons for event-shape selected collisions. In this way it is possible to get information on how the heavy quarks propagating (and hadronizing) in a hot environment respond both to its energy density and to its geometric asymmetry, breaking the perfect correlation between eccentricity and impact parameter which characterizes a modelling of the medium based on smooth average initial condition