A Generational Model of Political Learning

We propose a mathematical framework for modeling opinion change using large-scale longitudinal data sets. Our framework encompasses two varieties of Bayesian learning theory as well as Mannheim's theory of generational responses to political events. The basic assumptions underlying the model are (1) that historical periods are characterized by shocks to existing political opinions, and (2) that individuals of different ages may attach different weights to those political shocks. Political generations emerge endogenously from these basic assumptions: the political views of identifiable birth cohorts differ, and evolve distinctively through time, due to the interaction of age-specific weights with period-specific shocks. We employ this model to examine generational changes in party identification using survey data from the American National Election Studies

Predispositions and the Political Behavior of American Economic Elites: Evidence from Technology Entrepreneurs

Economic elites regularly seek to exert political influence. But what policies do they support? Many accounts implicitly assume economic elites are homogeneous and that increases in their political power will increase inequality. We shed new light on heterogeneity in economic elites' political preferences, arguing that economic elites from an industry can share distinctive preferences due in part to sharing distinctive predispositions. Consequently, how increases in economic elites' influence affect inequality depends on which industry's elites are gaining influence and which policy issues are at stake. We demonstrate our argument with four original surveys, including the two largest political surveys of American economic elites to date: one of technology entrepreneurs—whose influence is burgeoning—and another of campaign donors. We show that technology entrepreneurs support liberal redistributive, social, and globalistic policies but conservative regulatory policies—a bundle of preferences rare among other economic elites. These differences appear to arise partly from their distinctive predispositions

Impact Parameter Dependence in the Balitsky-Kovchegov Equation

We study the impact parameter dependence of solutions to the Balitsky-Kovchegov (BK) equation. We argue that if the kernel of the BK integral equation is regulated to cutoff infrared singularities, then it can be approximated by an equation without diffusion in impact parameter. For some purposes, when momentum scales large compared to $\Lambda_{QCD}$ are probed, the kernel may be approximated as massless. In particular, we find that the Froissart bound limit is saturated for physical initial conditions and seem to be independent of the cutoff so long as the cutoff is sufficiently large compared to the momentum scale associated with the large distance falloff of the impact parameter distribution.Comment: 15 pages, 7 figure

A Gaussian effective theory for gluon saturation

We construct a Gaussian approximation to the effective theory for the Colour Glass Condensate which describes correctly the gluon distribution both in the low density regime at high transverse momenta (above the saturation scale $Q_s$), and in the high density regime below $Q_s$, and provides a simple interpolation between these two regimes. At high momenta, the effective theory reproduces the BFKL dynamics, while at low momenta, it exhibits gluon saturation and, related to it, colour neutrality over the short distance scale $1/Q_s \ll 1/\Lambda_{QCD}$. Gauge--invariant quantities computed within this approximation are automatically infrared finite.Comment: 41 pages, 7 figur

The Statistical Analysis of Roll Call

We develop a Bayesian estimation procedure for spatial models of roll call voting. We show how a Bayesian approach to roll call analysis overcomes shortcomings and idiosyncracies of NOMINATE (some of which are not widely recognized). Our Bayesian approach (a) applies to any legislative setting, irrespective of size, legislative extremism, or the number of roll calls available for analysis; (b) provides a mechanism for directly incorporating auxiliary information as to the dimensionality of the underlying policy space, the identity of extremist legislators, key votes and the evolution of the legislative agenda; (c) lets us integrate measurement of legislative preferences with the analysis of those preferences. Notes to NEMP, May 2002 This paper sets out our ‘‘basic setup’ ’ (a Bayesian statistical operationalization of the Euclidean spatial voting model with roll call data), and constrasts it with the NOMINATE algorithms of Poole and Rosenthal. In the talk I will be considering extensions to our model, so as to accommodate and/or test conjectures in the literature on legislative politics (most prominently, the ‘‘party discipline’ ’ hypothesis, and conjectures about legislative responsiveness to constituency interests)

Parton saturation and N_part scaling of semi--hard processes in QCD

We argue that the suppression of high p_t hadrons discovered recently in heavy ion collisions at RHIC may be a consequence of saturation in the Color Glass Condensate. We qualitatively and semi-quantitatively describe the data, in particular, the dependence upon the number of nucleon participants. We show that if parton saturation sets in at sufficiently small energy, then in nucleus-nucleus collisions at RHIC and LHC energies the cross sections of semi-hard processes should scale approximately with the number of participants, N_{part}. Our results provide a possible explanation of both the absence of apparent jet quenching at SPS energies and its presence at RHIC. Under the same assumption we predict that in semi--central and central pA (dA) collisions at collider energies the dependence of semi--hard processes on the number of participating nucleons of the nucleus will change to \sim (N_{part}^A)^{1/2}. The forthcoming data on dA collisions will provide a crucial test of this description.Comment: 13 pages, 3 figures, LaTeX; significantly extended versio

New Forms of QCD Matter Discovered at RHIC

We discuss two special limiting forms of QCD matter which may be produced at RHIC. We conclude from the available empirical evidence that an equilibrated, but strongly coupled Quark Gluon Plasma has been made in such collisions. We also discuss the growing body of evidence that its source is a Color Glass Condensate.Comment: RBRC Scientific Artricles Vol.9, New Discoveries at RHIC: the current case for the strongly interactive QGP, BNL May 14,15 2004. References added and updated. Typos corrected. Accepted in Nucl.Phys.