1,349 research outputs found
Radion/Dilaton-Higgs Mixing Phenomenology in Light of the LHC
Motivated by the bulk mixing between a massive radion
and a bulk scalar Higgs in warped extra dimensions, we construct an effective
four dimensional action that---via the AdS/CFT correspondence---describes the
most general mixing between the only light states in the theory, the dilaton
and the Higgs. Due to conformal invariance, once the Higgs scalar is localized
in the bulk of the extra-dimension the coupling between the dilaton and the
Higgs kinetic term vanishes, implying a suppressed coupling between the dilaton
and massive gauge bosons. We comment on the implications of the mixing and
couplings to Standard Model particles. Identifying the recently discovered 125
GeV resonance with the lightest Higgs-like mixed state , we study the
phenomenology and constraints for the heaviest radion-like state . In
particular we find that in the small mixing scenario with a radion-like state
in the mass range [150,250] GeV, the diphoton channel can provide
the best chance of discovery at the LHC if the collaborations extend their
searches into this energy range.Comment: 28 pages, 6 figures; v2: version published in JHE
Implications of diphoton searches for a Radion in the Bulk-Higgs Scenario
In this work we point out that the apparent diphoton excess initially
presented by the ATLAS and CMS collaborations could have originated from a
radion in the bulk Higgs scenario within a warped extra dimension. In this
scenario the couplings of the radion to massive gauge bosons are suppressed,
allowing it to evade existing searches. In the presence of mixing with the
Higgs, due to the strong constraints from diboson searches, only points near
what we denominate the alignment region were able to explain the diphoton
signal and evade other experimental constraints. In light of the new
measurements presented at ICHEP 2016 by both LHC collaborations, which do not
confirm the initial diphoton excess, we study the current and future collider
constraints on a radion within the bulk-Higgs scenario. We find that searches
in the diphoton channel provide the most powerful probe of this scenario and
already exclude large regions of parameter space, particularly for smaller warp
factors. The radion has a sizeable branching ratio into top pairs and this
channel may also give competitive constraints in the future. Finally, diHiggs
searches can provide a complementary probe in the case of non-zero radion-Higgs
mixing but strong alignment.Comment: 20 pages, 12 figures. Several changes including consequences from
ICHEP2016. Final version accepted by journa
Novel Collider and Dark Matter Phenomenology of a Top-philic Z'
We consider extending the Standard Model by including an additional Abelian
gauge group broken at low energies under which the right-handed top quark is
the only effectively charged Standard Model fermion. The associated gauge boson
is then naturally top-philic and couples only to the rest of the SM
particle content at loop-level or via kinetic mixing with the hypercharge gauge
boson which is assumed to be small. Working at the effective theory level, we
demonstrate that such a minimal extension allows for an improved fitting of the
excess observed in searches at the LHC in a region
of parameter space that satisfies existing collider constraints. We also
present the reach of the LHC at 13 TeV in constraining the relevant region of
parameter space. Additionally we show that within the same framework a suitably
chosen fermion charged only under the exotic Abelian group can, in the region
of parameter space preferred by the measurements, simultaneously
explain the dark matter relic density and the -ray excess at the
galactic center observed by the Fermi-LAT experiment.Comment: 30 pages, 11 figures; v2: version published in JHE
Assessment of changes in ecosystem service delivery:a historical perspective on catchment landscapes
Although the relationships between habitats and ecosystem services (ESs) have been acknowledged, investigating spatio-temporal change in these has received far less attention. This study assesses the influence of habitat changes on ES delivery across space and time, based on two time points some 60 years apart, 1946 and 2009. A 1946 aerial photo coverage of two catchments in Scotland was used to construct digital photo mosaics which were then visually interpreted and digitised to derive historic habitat maps. Using the Spatial Evidence for Natural Capital Evaluation (SENCE) mapping approach, the derived habitat maps were translated into ES maps. These were then compared with contemporary ES maps of the two catchments, using the same mapping methodology. Increases in provisioning ESs were associated with increases in intensively managed habitats, with reductions in supply capacity of other regulating and supporting ESs associated with loss of semi-natural habitats. ES delivery was affected not only by gross area changes in habitats over time, but also by changes in configuration and spatial distribution of constituent habitats, including fragmentation and connectivity. It is argued that understanding historic changes in ESs adds an important strand in providing baselines to inform options for current and future management of catchments
Perfectionism and achievement goals in young Finnish ice-hockey players aspiring to make the Under-16 national team
Research on perfectionism suggests that is it useful to differentiate between perfectionistic strivings and perfectionistic concerns. Regarding the 2 x 2 achievement goal framework, the usefulness of this differentiation was recently demonstrated in a study with university student athletes (Stoeber, Stoll, Pescheck, & Otto, 2008, Study 2), in which it was found that perfectionistic strivings were associated with mastery-approach and performance-approach goals and perfectionistic concerns with mastery-avoidance, performance-approach, and performance-avoidance goals. Because the study was largely exploratory and only used non-elite athletes, the aim of the present research was to replicate and extend these findings by investigating a sample of 138 young, elite ice-hockey players, while adding further measures of perfectionism and using structural equation modelling (SEM) to confirm the relationships between perfectionistic strivings, perfectionistic concerns,and the 2 x 2 achievement goals. The SEM results showed that, in elite athletes also, perfectionistic strivings are associated with mastery-approach and performance-approach goals, whereas perfectionistic concerns are associated with masteryavoidance,
performance-approach, and performance-avoidance goals. Our findings corroborate the importance of differentiating between perfectionistic strivings and perfectionistic concerns when studying perfectionism in sports, because
only perfectionistic concerns (and not perfectionistic strivings) are associated with maladaptive patterns of achievement goals
Minimal Universal Extra Dimensions in CalcHEP/CompHEP
We present an implementation of the model of minimal universal extra
dimensions (MUED) in CalcHEP/CompHEP. We include all level-1 and level-2
Kaluza-Klein (KK) particles outside the Higgs sector. The mass spectrum is
automatically calculated at one loop in terms of the two input parameters in
MUED: the radius of the extra dimension and the cut-off scale of the model. We
implement both the KK number conserving and the KK number violating
interactions of the KK particles. We also account for the proper running of the
gauge coupling constants above the electroweak scale. The implementation has
been extensively cross-checked against known analytical results in the
literature and numerical results from other programs. Our files are publicly
available and can be used to perform various automated calculations within the
MUED model.Comment: 32 pages, 4 figures, 6 tables, invited contribution for New Journal
of Physics Focus Issue on 'Extra Space Dimensions', the model file can be
downloaded from http://home.fnal.gov/~kckong/mued
OECD principles on water governance in practice:an assessment of existing frameworks in Europe, Asia-Pacific, Africa and South America
Through the lens of the 12 OECD Principles on Water Governance, this article examines six water resources and water services frameworks in Europe, Asia-Pacific, Africa and South America to understand enhancing and constraining contextual factors. Qualitative and quantitative methods are used to analyze each framework against four criteria: alignment; implementation; on-ground results; and policy impact. Four main target areas are identified for improving water governance: policy coherence; financing; managing trade-offs; and ensuring integrity and transparency by all decision makers and stakeholders. Suggestions are presented to support practical implementation of the principles through better government action and stakeholder involvement.No Full Tex
Can sacrificial feeding areas protect aquatic plants from herbivore grazing? Using behavioural ecology to inform wildlife management
Effective wildlife management is needed for conservation, economic and human well-being objectives. However, traditional population control methods are frequently ineffective, unpopular with stakeholders, may affect non-target species, and can be both expensive and impractical to implement. New methods which address these issues and offer effective wildlife management are required. We used an individual-based model to predict the efficacy of a sacrificial feeding area in preventing grazing damage by mute swans (Cygnus olor) to adjacent river vegetation of high conservation and economic value. The accuracy of model predictions was assessed by a comparison with observed field data, whilst prediction robustness was evaluated using a sensitivity analysis. We used repeated simulations to evaluate how the efficacy of the sacrificial feeding area was regulated by (i) food quantity, (ii) food quality, and (iii) the functional response of the forager. Our model gave accurate predictions of aquatic plant biomass, carrying capacity, swan mortality, swan foraging effort, and river use. Our model predicted that increased sacrificial feeding area food quantity and quality would prevent the depletion of aquatic plant biomass by swans. When the functional response for vegetation in the sacrificial feeding area was increased, the food quantity and quality in the sacrificial feeding area required to protect adjacent aquatic plants were reduced. Our study demonstrates how the insights of behavioural ecology can be used to inform wildlife management. The principles that underpin our model predictions are likely to be valid across a range of different resource-consumer interactions, emphasising the generality of our approach to the evaluation of strategies for resolving wildlife management problems
- …
