On the Dipole Swing and the Search for Frame Independence in the Dipole Model

Small-x evolution in QCD is conveniently described by Mueller's dipole model which, however, does not include saturation effects in a way consistent with boost invariance. In this paper we first show that the recently studied zero and one dimensional toy models exhibiting saturation and explicit boost invariance can be interpreted in terms positive definite k-> k+1 dipole vertices. Such k-> k+1 vertices can in the full model be generated by combining the usual dipole splitting with k-1 simultaneous dipole swings. We show that, for a system consisting of N dipoles, one needs to combine the dipole splitting with at most N-1 simultaneous swings in order to generate all colour correlations induced by the multiple dipole interactions

Diffractive Excitation in DIS and pp Collisions

We have in earlier papers presented an extension of Mueller's dipole cascade model, which includes subleading effects from energy conservation and running coupling as well as colour suppressed effects from pomeron loops via a ``dipole swing''. The model was applied to describe the total cross sections in pp and gamma*p collisions. In this paper we present a number of improvements of the model, in particular related to the confinement mechanism. A consistent treatment of dipole evolution and dipole--dipole interactions is achieved by replacing the infinite range Coulomb potential by a screened potential, which further improves the frame-independence of the model. We then apply the model to elastic scattering and diffractive excitation, where we specifically study the effects of different sources for fluctuations. In our formalism we can take into account contributions from all different sources, from the dipole cascade evolution, the dipole--dipole scattering, from the impact-parameter dependence, and from the initial photon and proton wavefunctions. Good agreement is obtained with data from the Tevatron and from HERA, and we also present some predictions for the LHC.Comment: correction of titl

Energy Conservation and Pomeron Loops in High Energy Evolution

We present a formalism which modifies the Mueller Dipole Model such that it incorporates energy-momentum conservation and also important colour suppressed effects. We implement our formalism in a Monte Carlo simulation and compare the results to inclusive data from HERA and the Tevatron, where we see that there is a good agreement between the data and our model.Comment: Figure 6 update

Geometric Scaling and QCD Dynamics in DIS

DIS data from HERA show a striking regularity as \sigma^{\gamma^* p} is a function of the ratio \tau=Q^2/Q_s^2(x) only. The scaling function shows a break at \tau ~ 1, which has been taken as an indication for saturation. However, besides saturation also the transition between dominance of k_t-ordered (DGLAP) and k_t-non-ordered (BFKL) evolution contributes to a break around this value of \tau, as well as the suppression for small Q^2 due to finite quark masses and confinement. In this paper we use a dipole cascade model based on Mueller's dipole model, which also includes energy conservation and pomeron mergins, to investigate the contributions of these different effects to the scaling behaviour. As a result we predict that the scaling function for \tau 1 GeV^2 become available. We also investigate the scaling properties of the charm contribution and the impact parameter dependence of the saturation scale.Comment: references added, figures 2, 7 and 8 updated v3: reference added, some misprints correcte

Eccentricity and elliptic flow in proton-proton collisions from parton evolution

It has been argued that high-multiplicity proton-proton collisions at the LHC may exhibit collective phenomena usually studied in the context of heavy-ion collisions, such as elliptic flow. We study this issue using DIPSY - a Monte Carlo event generator based on the QCD dipole model. We calculate the eccentricity of the transverse area defined by the spatial distribution of produced gluons. The resulting elliptic flow is estimated to be about 6%, comparable to the value in nucleus-nucleus collisions at RHIC and the LHC. Experimentally, elliptic flow is inferred from the azimuthal correlation between hadrons, which receives contributions from collective flow, and from various other effects referred to as "nonflow". We discuss how to identify in experiments the signal of flow in the presence of large nonflow effects.Comment: v2: Four-particle correlation added, improved discussions on the signatures of flow. v3: Improved treatment of fluctuations in the flow analysis. v4: Minor changes for journal submissio

Crystal and molecular structure of bis(4-bromo-N-(di-n-butylcarbamothioyl)benzamido) copper(II) complex

The title compound, C32H44Br2CuN4O2S2, was synthesized from 4-bromo-N-(dibutylcarbamothioyl)benzamide ligand and copper(II)acetate. The crystal structure of bis(4-bromo-N-(di-n-butylcarbamothioyl)benzamido) copper(II) complex was determined from single crystal X-ray diffraction studies. It crystallizes in the triclinic space group, P-1 (no. 2) with unit cell dimensions of a = 8.519(10) Å, b = 16.64(2) Å, c = 25.78(4) Å, α = 77.11(3)o, β = 85.59(3)o, γ = 89.46(2)o , Z = 4 and V = 795.8(6) Å3. The crystal structure is stabilized by weak C-H…N, C-H…S and C-H…Br hydrogen-bonding interactions

State-Owned Enterprises, Political Ideology, and Redistribution

Many economies have undergone the process of privatizing their state-owned enterprises. Recently, however, this process has slowed down in some economies and has been completely stalled in others. Here we formalize the view that this is so because these enterprises are major instruments of income redistribution and, in economies with significant degrees of income inequality, segments of the population that benefit from this redistribution would use their political power to oppose its abandonment. We find strong empirical support for this hypothesis using cross-country data on the relative size of the state-owned-enterprise sector. We also find robust evidence that left-wing (vis-à-vis right-wing) governments are associated with greater redistribution in more unequal societies. Further, this effect is non-linear, implying that redistribution becomes more costly at higher levels of inequality. We also find the same result for authoritarian (vis-à-vis democratic) governments.

Using flotation in ethanol to separate filled and empty seeds of Pinus nigra ssp. pallasiana

In this study, the separation of filled and empty seeds of Crimean pine [Pinus nigra Arn. ssp. pallasiana (Lamb.) Holmboe] by flotation in ethanol and the effect of this treatment on seed germination were investigated. Flotation tests in 96% ethanol by the density method and then germination tests were made on the seeds from three Crimean pine provenances of southern Turkey. In the flotation tests, 97.92% of the filled seeds sank in ethanol and 98.73% of the sunken seeds were filled seeds as the general mean values of all the provenances. Germination percentages of the flotation in ethanol and control treatments were 98.03 and 98.62%, and germination energies were 82.12 and 79.45%,respectively, in the general mean. While there was no statistically significant difference (p > 0.05) between the flotation and control treatments in terms of germination percentage for all three provenances, there was no significant difference (p > 0.05) for two provenances; however, there was a significant difference (p < 0.05) for one provenance in favour of the flotation treatment in terms of germination energy. The results of the study indicated that filled seeds of Crimean pine could beseparated from empty seeds at a very high proportion by flotation in ethanol and this treatment did not affect negatively the germination percentage and germination energy of the seeds