Hidden-Sector Higgs Bosons at High-Energy Electron-Positron Colliders

The possibility of a scalar messenger that can couple the Standard Model (SM) to a hidden sector has been discussed in a variety of contexts in the literature in recent years. We consider the case that a new scalar singlet charged under an exotic spontaneously broken Abelian gauge symmetry mixes weakly with the SM Higgs resulting in two scalar mass states, one of which has heavily suppressed couplings to the SM particles. Previous phenomenological studies have focussed on potential signatures for such a model at the Large Hadron Collider (LHC). However, there are interesting regions of the parameter space in which the heavier Higgs state would be out of reach for LHC searches if its mass is greater than 1 TeV. We therefore investigate the discovery potential for such a particle at a 3 TeV electron-positron collider, which is motivated by the recent developments of the Compact Linear Collider (CLIC). We find that such an experiment could substantially extend our discovery reach for a heavy, weakly coupled Higgs boson, and we discuss three possible search channels.Comment: 14 pages, 8 Figures. Published as an LCD Not

Specifying attracting cycles for Newton maps of polynomials

We show that for any set of n distinct points in the complex plane, there exists a polynomial p of degree at most n+1 so that the corresponding Newton map, or even the relaxed Newton map, for p has the given points as a super-attracting cycle. This improves the result due to Plaza and Romero (2011), which shows how to find such a polynomial of degree 2n. Moreover we show that in general one cannot improve upon degree n+1. Our methods allow us to give a simple, constructive proof of the known result that for each cycle length n at least 2 and degree d at least 3, there exists a polynomial of degree d whose Newton map has a super-attracting cycle of length n.Comment: 18 pages, 2 figure

Sudakov Logarithm Resummation in Transverse Momentum Space for Electroweak Boson Production at Hadron Colliders

A complete description of W and Z boson production at high-energy hadron colliders requires the resummation of large Sudakov double logarithms which dominate the transverse momentum (q_T) distribution at small q_T. We compare different prescriptions for performing this resummation, in particular implicit impact parameter space resummation versus explicit transverse momentum space resummation. We argue that the latter method can be formulated so as to retain the advantages of the former, while at the same time allowing a smooth transition to finite order dominance at high q_T.Comment: 32 pages, Latex, epsfig, 17 figure

Measuring Effective Tax Rates on Human Capital: Methodology and an Application to Canada

This paper examines the impacts of a wide range of tax provisions on the incentive to invest in human capital, and shows how these effects can be quantified using effective tax rates, or ETRs. For individuals with median earnings, ETRs on the human capital formed in first-degree university study are sizeable, although not as large as those estimated by previous authors for physical capital in Canada. When the expenditure side and its direct subsidies are also taken into account, the net effective tax rate on human capital becomes negative. The taxation of human capital is far from uniform. ETRs vary by income level, gender, part-time vs. full-time study, whether students have loans, number of dependants, and use of RESPs. The most significant differences are those related to income level. Workers at higher percentile levels of the earnings distribution throughout life may face ETRs three times as high as those for low-income workers – a result of our progressive income tax system.

COMMODITY PROGRAMS AND RURAL REVITALIZATION

Community/Rural/Urban Development,

Higher Education Academic Salaries in the UK

The recent industrial action taken by the Association of University Teachers (AUT) has given the issue of academic pay high prominence in the UK press. There appears to be a remarkable consensus that higher education academic salaries are too low, relative to other groups of workers in the UK, and that this is leading to an academic 'brain drain'. There is concern that this in turn will result in lower quality higher education, as universities fail to attract the 'brightest and the best'. To rise above the rhetoric, there is a pressing need for robust evidence on relative academic salaries. In this paper, we compare the salaries of Higher Education teaching professionals in the United Kingdom with those of other comparable professionals. We offer evidence on relative salaries in HE academia over the last decade or so and we compare academic salaries to a range of different comparator groups, including some specific occupational groupings that one might view as more similar, in terms of unobserved characteristics, to academics. We then consider the extent to which the gap between the earnings of HE academics and that of other occupations is attributable to differences in the characteristics of academics, for example the fact that they are more highly educated on average, or to differences in the price paid for a given set of characteristics. We conclude that HE teaching professionals earn somewhat lower earnings than most public sector graduates and do particularly poorly compared to most other comparable professionals; they also work longer hours than most. In particular, academic earnings compare poorly to those in the legal professions, consultants physicians and dental practitioners (across both the public and private sectors). On the other hand, there are groups of public sector workers that do worse than HE academics, and in particular FE academics earn significantly less.higher educatio