Little Higgs Phenomenology

Recently a new class of models has emerged that addresses the naturalness problem of a light Higgs boson. In these ''little Higgs'' models, the Standard Model Higgs boson is a pseudo-Nambu-Goldstone boson of an approximate global symmetry. The Higgs boson acquires mass radiatively only through ''collective breaking'' of the global symmetry, so that more than one interaction is required to give the Higgs a mass. This protects the Higgs mass from receiving quadratically divergent radiative corrections at one-loop. These models contain new vector bosons, fermions and scalars at the TeV scale that cancel the quadratic divergences in the Higgs mass due to the Standard Model gauge, top quark, and Higgs boson loops. In this talk I review the phenomenology of the little Higgs models, focusing on collider signatures and electroweak precision constraints.Comment: 3 pages, 2 figures, talk given at EPS 2003, Aachen, Germany, July 200

Dark matter annihilation through a lepton-specific Higgs boson

It was recently argued by Hooper and Goodenough [arXiv:1010.2752] that the excess gamma ray emission from within 1-2 degrees of the galactic center can be well-described by annihilation of ~8 GeV dark matter particles into tau pairs. I show that such a dark matter signal can be obtained naturally in the lepton-specific two-Higgs-doublet model extended by a stable singlet scalar dark matter candidate. The favored parameter region prefers a light Higgs state (below 200 GeV) with enhanced couplings to leptons and sizable invisible branching fraction. Part of the favored region leads to invisible decays of both of the CP-even neutral Higgs states.Comment: 15 pages, no figures. V2: references added, fine-tuning discussion improved, submitted to PRD. V3: added Sec. 6 on direct detection prospects and associated refs, version accepted by PR

TASI 2013 lectures on Higgs physics within and beyond the Standard Model

These lectures start with a detailed pedagogical introduction to electroweak symmetry breaking in the Standard Model, including gauge boson and fermion mass generation and the resulting predictions for Higgs boson interactions. I then survey Higgs boson decays and production mechanisms at hadron and e+e- colliders. I finish with two case studies of Higgs physics beyond the Standard Model: two-Higgs-doublet models, which I use to illustrate the concept of minimal flavor violation, and models with isospin-triplet scalar(s), which I use to illustrate the concept of custodial symmetry.Comment: 48 pages, 25 figures, comments welcome. v2: fixed nonstandard convention for SU(2) generators T+/T- (changes in Eqs. 46, 47, 51, 163, 164, and 165

Beyond Infrastructure: Broadband for Development in Remote and Indigenous Regions

Recent telecommunications stimulus projects in the U.S. and Canada were intended to increase availability of broadband through funding infrastructure investments, largely in rural and remote regions. However, true access involves more than availability; it also includes affordability and adoption. This paper presents a framework for analyzing broadband adoption that takes into consideration geographical, economic and cultural environments in indigenous communities. It includes an overview of potential social and economic impacts of broadband in remote areas, using examples from the Alaska study and the Canadian North. It then reports on results of an evaluation of Internet use and potential adoption of broadband in remote indigenous communities of southwest Alaska. Finally, the paper provides a comparative analysis of U.S. and Canadian policies intended to achieve affordable access to broadband for rural users and sustainable business models for rural broadband providers.Ye

Digital Diversity: Broadband and Indigenous Populations in Alaska

Presented at the Experts Workshop. Sponsored by the Ford Foundation.Alaska Natives comprise several cultural and linguistic groups including Inupiat, Yupik, Athabascan, Aleut, Tlingit and Haida, organized into some 226 tribes. Approximately two-thirds of the indigenous population live in more than 200 rural villages, most of which are remote settlements with fewer than 200 people and no road access. Since the late 1970’s, all communities with at least 25 permanent residents have had telephone service, but broadband connectivity remains limited. The major mechanism for extending Internet access to rural Alaska has been federal universal service funds, specifically the E-rate program that subsidizes Internet access for schools and libraries, and the Rural Health program that subsidizes connectivity for rural health clinics and hospitals. Under the federal Stimulus program, Alaska has also recently received funding for infrastructure to extend broadband in southwest Alaska, for improved connectivity for rural libraries, and for training and support for rural public computer centers. These initiatives primarily support improvements in Internet and broadband availability for rural Alaska. However, this paper proposes a more rigorous framework including not only availability, but more broadly access, and also adoption, and examines how these concepts apply to Alaska natives. The paper also examines other elements of digital diversity, including innovation in applications and content, ICT entrepreneurship, and participation in telecommunications policy-making

Starting life in Scotland in the new millennium : population replacement and the reproduction of disadvantage

Scotland, in line with the rest of Europe, is experiencing low rates of child-bearing and its population is ageing. This does not necessarily mean that people in Scotland are going grey at a faster rate than they used to. Rather, it means that there is an increasing proportion of elderly people in its population, with more people who are growing old than are growing up. The "birth dearth" and "population greying" are not unconnected: low fertility is the key influence on the age structure of a population as well as the rate of population growth