Dangerous Skyrmions in Little Higgs Models

Skyrmions are present in many models of electroweak symmetry breaking where the Higgs is a pseudo-Goldstone boson of some strongly interacting sector. They are stable, composite objects whose mass lies in the range 10-100 TeV and can be naturally abundant in the universe due to their small annihilation cross-section. They represent therefore good dark matter candidates. We show however in this work that the lightest skyrmion states are electrically charged in most of the popular little Higgs models, and hence should have been directly or indirectly observed in nature already. The charge of the skyrmion under the electroweak gauge group is computed in a model-independent way and is related to the presence of anomalies in the underlying theory via the Wess-Zumino-Witten term.Comment: 31 pages, 4 figures; v2: minor changes, one reference added, version to appear in JHEP; v3: erratum added, conclusions unchange

Discovery potential of top-partners in a realistic composite Higgs model with early LHC data

Composite Higgs models provide a natural, non-supersymmetric solution to the hierarchy problem. In these models, one or more sets of heavy top-partners are typically introduced. Some of these new quarks can be relatively light, with a mass of a few hundred GeV, and could be observed with the early LHC collision data expected to be collected during 2010. We analyse in detail the collider signatures that these new quarks can produce. We show that final states with two (same-sign) or three leptons are the most promising discovery channels. They can yield a 5 sigma excess over the Standard Model expectation already with the 2010 LHC collision data. Exotic quarks of charge 5/3 are a distinctive feature of this model. We present a new method to reconstruct their masses from their leptonic decay without relying on jets in the final state.Comment: 28 pages 11 Figures 7 Tables, minor changes, added references, matches published versio

Higgs Low-Energy Theorem (and its corrections) in Composite Models

The Higgs low-energy theorem gives a simple and elegant way to estimate the couplings of the Higgs boson to massless gluons and photons induced by loops of heavy particles. We extend this theorem to take into account possible nonlinear Higgs interactions resulting from a strong dynamics at the origin of the breaking of the electroweak symmetry. We show that, while it approximates with an accuracy of order a few percents single Higgs production, it receives corrections of order 50% for double Higgs production. A full one-loop computation of the gg->hh cross section is explicitly performed in MCHM5, the minimal composite Higgs model based on the SO(5)/SO(4) coset with the Standard Model fermions embedded into the fundamental representation of SO(5). In particular we take into account the contributions of all fermionic resonances, which give sizeable (negative) corrections to the result obtained considering only the Higgs nonlinearities. Constraints from electroweak precision and flavor data on the top partners are analyzed in detail, as well as direct searches at the LHC for these new fermions called to play a crucial role in the electroweak symmetry breaking dynamics.Comment: 30 pages + appendices and references, 12 figures. v2: discussion of flavor constraints improved; references added; electroweak fit updated, results unchanged. Matches published versio

Exploring T and S parameters in Vector Meson Dominance Models of Strong Electroweak Symmetry Breaking

We revisit the electroweak precision tests for Higgsless models of strong EWSB. We use the Vector Meson Dominance approach and express S and T via couplings characterizing vector and axial spin-1 resonances of the strong sector. These couplings are constrained by the elastic unitarity and by requiring a good UV behavior of various formfactors. We pay particular attention to the one-loop contribution of resonances to T (beyond the chiral log), and to how it can improve the fit. We also make contact with the recent studies of Conformal Technicolor. We explain why the second Weinberg sum rule never converges in these models, and formulate a condition necessary for preserving the custodial symmetry in the IR.Comment: 35 pages, 7 figures; v3: refs added, to appear in JHE

Composite Higgs Sketch

The coupling of a composite Higgs to the standard model fields can deviate substantially from the standard model values. In this case perturbative unitarity might break down before the scale of compositeness is reached, which would suggest that additional composites should lie well below this scale. In this paper we account for the presence of an additional spin 1 custodial triplet of rhos. We examine the implications of requiring perturbative unitarity up to the compositeness scale and find that one has to be close to saturating certain unitarity sum rules involving the Higgs and the rho couplings. Given these restrictions on the parameter space we investigate the main phenomenological consequences of the spin 1 triplet. We find that they can substantially enhance the Higgs di-photon rate at the LHC even with a reduced Higgs coupling to gauge bosons. The main existing LHC bounds arise from di-boson searches, especially in the experimentally clean channel where the charged rhos decay to a W-boson and a Z, which then decay leptonically. We find that a large range of interesting parameter space with 700 GeV < m(rho) < 2 TeV is currently experimentally viable.Comment: 37 pages, 12 figures; v4: sum rule corrected, conclusions unchange

Violence in primary care: Prevalence and follow-up of victims

BACKGROUND: Primary care physicians underestimate the prevalence of domestic violence and community violence. Victims are therefore at risk of further episodes of violence, with psychological and physical consequences. We used an interview to assess the prevalence of domestic and community violence among Swiss natives and foreigners. In a follow-up study, we evaluated the consequences of the interview for the positive patients. METHODS: We evaluated the prevalence of violence by use of a questionnaire in an interview, in an academic general internal medicine clinic in Switzerland. In a follow-up, we evaluated the consequences of the interview for positive patients. The participants were 38 residents and 446 consecutive patients. Questionnaires were presented in the principal language spoken by our patients. They addressed sociodemographics, present and past violence, the security or lack of security felt by victims of violence, and the patients' own violence. Between 3 and 6 months after the first interview, we did a follow-up of all patients who had reported domestic violence in the last year. RESULTS: Of the 366 patients included in the study, 36 (9.8%) reported being victims of physical violence during the last year (physicians identified only 4 patients out of the 36), and 34/366 (9.3%) reported being victims of psychological violence. Domestic violence was responsible for 67.3% of the cases, and community violence for 21.8%. In 10.9% of the cases, both forms of violence were found. Of 29 patients who reported being victims of domestic violence, 22 were found in the follow-up. The frequency of violence had diminished (4/22) or the violence had ceased (17/22). CONCLUSION: The prevalence of violence is high; domestic violence is more frequent than community violence. There was no statistically significant difference between the Swiss and foreign patients' responses related to the rates of violence. Patients in a currently violent relationship stated that participating in the study helped them and that the violence decreased or ceased a few months later

Developing assessments for child exposure to intimate partner violence in Switzerland – A study of medico-legal reports in clinical settings

Purpose: Evidence to inform assessment of needs of children exposed to intimate partner violence (IPV) in health settings is limited. A Swiss hospital-based medico-legal consultation for adult victims of violence also detects children’s exposure to IPV and refers cases to the Pediatrics Child Abuse and Neglect Team. Based on a conceptual ecological framework, this study examined the nature and circumstances of children’s exposure to IPV described in accounts collected by nurses in consultations with adult IPV victims. Methods: From 2011-2014, 438 parents (88% female) of 668 children aged 0 to 18 sought medico-legal care from the Violence Medical Unit in Lausanne Switzerland, following assaults by intimate partners (85% male). As part of the consultation, nurses completed a semi-structured questionnaire with victimized parents, recording their answers in the patient file. Victims’ statements about the abuse, their personal, family and social contexts, and their children’s exposure to IPV were analyzed. Descriptive statistics and qualitative thematic content analyses were conducted to identify, from the victimized parents’ accounts, elements useful to understand the nature and circumstances of children’s exposure and involvement during violent events. Results: Parent statements on specific violent events described children being present in 75% of the cases. Children were said to be exposed to, and responded to, severe physical violence, serious threats and insults, in the context of repeated assaults and coercive control. Families, especially mothers, were often coping with additional socio-economic vulnerabilities. Conclusions: Implications for further developing assessments of children living with IPV, especially in health settings were identified

On non-supersymmetric conformal manifolds: field theory and holography

We discuss the constraints that a conformal field theory should enjoy to admit exactly marginal deformations, i.e. to be part of a conformal manifold. In particular, using tools from conformal perturbation theory, we derive a sum rule from which one can extract restrictions on the spectrum of low spin operators and on the behavior of OPE coefficients involving nearly marginal operators. We then consider conformal field theories admitting a gravity dual description, and as such a large-$N$ expansion. We discuss the relation between conformal perturbation theory and loop expansion in the bulk, and show how such connection could help in the search for conformal manifolds beyond the planar limit. Our results do not rely on supersymmetry, and therefore apply also outside the realm of superconformal field theories