4,599 research outputs found

    Rights-based reasoning in discussions about lesbian and gay issues: implications for moral educators

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    Despite a paucity of psychological research exploring the interface between lesbian and gay issues and human rights, a human rights framework has been widely adopted in debates to gain equality for lesbians and gay men. Given this prominence within political discourse of human rights as a framework for the promotion of positive social change for lesbians and gay men, the aim of this study was to explore the extent to which rights-based arguments are employed when talking about lesbian and gay issues in a social context. An analysis of six focus group discussions with students showed that when lesbian and gay issues are discussed, rights-based reasoning is employed intermittently, and in relation to certain issues more so than others. The implications of these findings for moral education aimed at promoting positive social change for lesbians and gay men are discussed.</p

    Skyrmion Multi-Walls

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    Skyrmion walls are topologically-nontrivial solutions of the Skyrme system which are periodic in two spatial directions. We report numerical investigations which show that solutions representing parallel multi-walls exist. The most stable configuration is that of the square NN-wall, which in the NN\to\infty limit becomes the cubically-symmetric Skyrme crystal. There is also a solution resembling parallel hexagonal walls, but this is less stable.Comment: 7 pages, 1 figur

    Phenomenology and Cosmology of an Electroweak Pseudo-Dilaton and Electroweak Baryons

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    In many strongly-interacting models of electroweak symmetry breaking the lowest-lying observable particle is a pseudo-Goldstone boson of approximate scale symmetry, the pseudo-dilaton. Its interactions with Standard Model particles can be described using a low-energy effective nonlinear chiral Lagrangian supplemented by terms that restore approximate scale symmetry, yielding couplings of the pseudo-dilaton that differ from those of a Standard Model Higgs boson by fixed factors. We review the experimental constraints on such a pseudo-dilaton in light of new data from the LHC and elsewhere. The effective nonlinear chiral Lagrangian has Skyrmion solutions that may be identified with the `electroweak baryons' of the underlying strongly-interacting theory, whose nature may be revealed by the properties of the Skyrmions. We discuss the finite-temperature electroweak phase transition in the low-energy effective theory, finding that the possibility of a first-order electroweak phase transition is resurrected. We discuss the evolution of the Universe during this transition and derive an order-of-magnitude lower limit on the abundance of electroweak baryons in the absence of a cosmological asymmetry, which suggests that such an asymmetry would be necessary if the electroweak baryons are to provide the cosmological density of dark matter. We revisit estimates of the corresponding spin-independent dark matter scattering cross section, with a view to direct detection experiments.Comment: 34 pages, 4 figures, additional references adde

    Higgs and Dark Matter Hints of an Oasis in the Desert

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    Recent LHC results suggest a standard model (SM)-like Higgs boson in the vicinity of 125 GeV with no clear indications yet of physics beyond the SM. At the same time, the SM is incomplete, since additional dynamics are required to accommodate cosmological dark matter (DM). In this paper we show that interactions between weak scale DM and the Higgs which are strong enough to yield a thermal relic abundance consistent with observation can easily destabilize the electroweak vacuum or drive the theory into a non-perturbative regime at a low scale. As a consequence, new physics--beyond the DM itself--must enter at a cutoff well below the Planck scale and in some cases as low as O(10 - 1000 TeV), a range relevant to indirect probes of flavor and CP violation. In addition, this cutoff is correlated with the DM mass and scattering cross-section in a parameter space which will be probed experimentally in the near term. Specifically, we consider the SM plus additional spin 0 or 1/2 states with singlet, triplet, or doublet electroweak quantum numbers and quartic or Yukawa couplings to the Higgs boson. We derive explicit expressions for the full two-loop RGEs and one-loop threshold corrections for these theories.Comment: 29 pages, 13 figure

    Neutralino versus axion/axino cold dark matter in the 19 parameter SUGRA model

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    We calculate the relic abundance of thermally produced neutralino cold dark matter in the general 19 parameter supergravity (SUGRA-19) model. A scan over GUT scale parameters reveals that models with a bino-like neutralino typically give rise to a dark matter density \Omega_{\tz_1}h^2\sim 1-1000, i.e. between 1 and 4 orders of magnitude higher than the measured value. Models with higgsino or wino cold dark matter can yield the correct relic density, but mainly for neutralino masses around 700-1300 GeV. Models with mixed bino-wino or bino-higgsino CDM, or models with dominant co-annihilation or A-resonance annihilation can yield the correct abundance, but such cases are extremely hard to generate using a general scan over GUT scale parameters; this is indicative of high fine-tuning of the relic abundance in these cases. Requiring that m_{\tz_1}\alt 500 GeV (as a rough naturalness requirement) gives rise to a minimal probably dip in parameter space at the measured CDM abundance. For comparison, we also scan over mSUGRA space with four free parameters. Finally, we investigate the Peccei-Quinn augmented MSSM with mixed axion/axino cold dark matter. In this case, the relic abundance agrees more naturally with the measured value. In light of our cumulative results, we conclude that future axion searches should probe much more broadly in axion mass, and deeper into the axion coupling.Comment: 23 pages including 17 .eps figure

    Theoretical Aspects of Dark Matter Detection

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    Direct and indirect dark matter detection relies on the scattering of the dark matter candidate on nucleons or nuclei. Here, attention is focused on dark matter candidates (neutralinos) predicted in the minimal supersymmetric standard model and its constrained version with universal input soft supersymmetry-breaking masses. Current expectations for elastic scattering cross sections for neutralinos on protons are discussed with particular attention to satisfying all current accelerator constraints as well as insuring a sufficient cosmological relic density to account for the dark matter in the Universe

    Searches for Lepton Flavour Violation at a Linear Collider

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    We investigate the prospects for detection of lepton flavour violation in sparticle production and decays at a Linear Collider (LC), in models guided by neutrino oscillation data. We consider both slepton pair production and sleptons arising from the cascade decays of non-leptonic sparticles. We study the expected signals when lepton-flavour-violating (LFV) interactions are induced by renormalization effects in the Constrained Minimal Supersymmetric extension of the Standard Model (CMSSM), focusing on the subset of the supersymmetric parameter space that also leads to cosmologically interesting values of the relic neutralino LSP density. Emphasis is given to the complementarity between the LC, which is sensitive to mixing in both the left and right slepton sectors, and the LHC, which is sensitive primarily to mixing in the right sector. We also emphasize the complementarity between searches for rare LFV processes at the LC and in low-energy experiments.Comment: 19 pages, 10 figure

    Hitting sbottom in natural SUSY

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    We compare the experimental prospects of direct stop and sbottom pair production searches at the LHC. Such searches for stops are of great interest as they directly probe for states that are motivated by the SUSY solution to the hierarchy problem of the Higgs mass parameter - leading to a "Natural" SUSY spectrum. Noting that sbottom searches are less experimentally challenging and scale up in reach directly with the improvement on b-tagging algorithms, we discuss the interplay of small TeV scale custodial symmetry violation with sbottom direct pair production searches as a path to obtaining strong sub-TeV constraints on stops in a natural SUSY scenario. We argue that if a weak scale natural SUSY spectrum does not exist within the reach of LHC, then hopes for such a spectrum for large regions of parameter space should sbottom out. Conversely, the same arguments make clear that a discovery of such a spectrum is likely to proceed in a sbottom up manner.Comment: 18 pages, 8 figures,v2 refs added, JHEP versio

    Transition to parenthood and quality of parenting among gay, lesbian and heterosexual couples who conceived through assisted reproduction

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    Little research has focused on the emotions felt during pregnancy and early parenthood as well as the initial quality of parenting displayed by first-time parents who conceived using assisted reproduction technologies (surrogacy, donor insemination, and in vitro fertilization). Research on primary and secondary caregivers in gay, lesbian, and heterosexual families is especially sparse. The current study examined 35 gay-father families, 58 lesbian-mother families and 41 heterosexual-parent families with their infants. Families were assessed at home when their infants were 4 months old (±14 days), and each parent participated in an audio-recorded standardized semi-structured interview in which we explored parental feelings during pregnancy, feelings about the parental role, perceived parental competence, the enjoyment of parenthood, expressed warmth and emotional over-involvement of parents. 13 Heterosexual parents reported less positive feelings in early pregnancy than lesbian parents, while gay parents reported less positive feelings at the end of pregnancy than lesbian mothers and more positive feelings about parenthood during the first post-partum weeks than heterosexual parents. There was no interaction between family type and caregiver role on reported feelings, or on perceived competence, enjoyment, warmth, and involvement. The present findings elucidate the transition to parenthood among first-time parents conceiving through assisted reproductive technologies, and especially contribute to our knowledge about gay fathers who became parents through surrogacy

    The Universal One-Loop Effective Action

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    We present the universal one-loop effective action for all operators of dimension up to six obtained by integrating out massive, non-degenerate multiplets. Our general expression may be applied to loops of heavy fermions or bosons, and has been checked against partial results available in the literature. The broad applicability of this approach simplifies one-loop matching from an ultraviolet model to a lower-energy effective field theory (EFT), a procedure which is now reduced to the evaluation of a combination of matrices in our universal expression, without any loop integrals to evaluate. We illustrate the relationship of our results to the Standard Model (SM) EFT, using as an example the supersymmetric stop and sbottom squark Lagrangian and extracting from our universal expression the Wilson coefficients of dimension-six operators composed of SM fields.Comment: 30 pages, v2 contains additional comments and corrects typos, version accepted for publication in JHE
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