Preliminary results of the search for a Standard Model like Higgs boson at the LHC with 5 fb−1 data have just been presented by the ATLAS and CMS Collaborations and an excess of events at a mass of ...≈125 GeV has been reported. If this excess of events is confirmed by further searches with more data, it will have extremely important consequences in the context of supersymmetric extensions of the Standard Model and, in particular the minimal one, the MSSM. We show that for a standard-like Higgs boson with a mass 123<Mh<127 GeV, several unconstrained or constrained (i.e. with soft supersymmetry-breaking parameters unified at the high scale) MSSM scenarios would be excluded, while the parameters of some other scenarios would be severely restricted. Examples of constrained MSSM scenarios which would be disfavoured as they predict a too light Higgs particle are the minimal anomaly and gauge mediated supersymmetry-breaking models. The gravity mediated constrained MSSM would still be viable, provided the scalar top quarks are heavy and their trilinear coupling large. Significant areas of the parameter space of models with heavy supersymmetric particles, such as split or high-scale supersymmetry, could also be excluded as, in turn, they generally predict a too heavy Higgs particle.
A
bstract
The long awaited discovery of a new light scalar boson at the LHC opens up a new era of studies of the Higgs sector in the Standard Model and in its extensions. In this paper we discuss the ...consequences of the observation of a light Higgs boson with the mass and rates reported by the ATLAS and CMS collaborations on the parameter space of the phenomenological MSSM, accounting also for the LHC searches for heavier Higgs bosons and supersymmetric particle partners, as well as constraints from
B
-physics and dark matter. We explore the various regimes of the MSSM Higgs sector, depending on the parameters
M
A
and tan
β
, and show that only two of them are still allowed by all present experimental constraints: the decoupling regime, in which there is only one light and standard-like Higgs boson while the heavier Higgs states decouple from gauge bosons, and the supersymmetric regime, in which there are light supersymmetric particle partners which might affect the decay properties of the light Higgs boson, in particular its di-photon and invisible decays.
We study the implications of LHC searches on SUSY particle spectra using flat scans of the 19-parameter pMSSM phase space. We apply constraints from flavour physics, gμ−2, dark matter and earlier LEP ...and Tevatron searches. The sensitivity of the LHC SUSY searches with jets, leptons and missing energy is assessed by reproducing with fast simulation the recent CMS analyses after validation on benchmark points. We present results in terms of the fraction of pMSSM points compatible with all the constraints which are excluded by the LHC searches with 1 fb−1 and 15 fb−1 as a function of the mass of strongly and weakly interacting SUSY particles. We also discuss the suppression of Higgs production cross sections for the MSSM points not excluded and contrast the region of parameter space tested by the LHC data with the constraints from dark matter direct detection experiments.
High-energy X-rays and
γ
-rays from solar flares were discovered just over fifty years ago. Since that time, the standard for the interpretation of spatially integrated flare X-ray spectra at ...energies above several tens of keV has been the collisional thick-target model. After the launch of the
Reuven Ramaty High Energy Solar Spectroscopic Imager
(
RHESSI
) in early 2002, X-ray spectra and images have been of sufficient quality to allow a greater focus on the energetic electrons responsible for the X-ray emission, including their origin and their interactions with the flare plasma and magnetic field. The result has been new insights into the flaring process, as well as more quantitative models for both electron acceleration and propagation, and for the flare environment with which the electrons interact. In this article we review our current understanding of electron acceleration, energy loss, and propagation in flares. Implications of these new results for the collisional thick-target model, for general flare models, and for future flare studies are discussed.
This contribution discusses in brief recent results from the search for new physics beyond the Standard Model obtained by the ATLAS experiment with the analysis of up to 80 fb
–1
of 13 TeV LHC data. ...It is organised over three main themes: the Higgs sector and new physics, searches for dark matter motivated new physics scenarios and relations between QCD and searches for new physics.
Implementation of wildfire- and climate-adaptation strategies in seasonally dry forests of western North America is impeded by numerous constraints and uncertainties. After more than a century of ...resource and land use change, some question the need for proactive management, particularly given novel social, ecological, and climatic conditions. To address this question, we first provide a framework for assessing changes in landscape conditions and fire regimes. Using this framework, we then evaluate evidence of change in contemporary conditions relative to those maintained by active fire regimes, i.e., those uninterrupted by a century or more of human-induced fire exclusion. The cumulative results of more than a century of research document a persistent and substantial fire deficit and widespread alterations to ecological structures and functions. These changes are not necessarily apparent at all spatial scales or in all dimensions of fire regimes and forest and nonforest conditions. Nonetheless, loss of the once abundant influence of low- and moderate-severity fires suggests that even the least fire-prone ecosystems may be affected by alteration of the surrounding landscape and, consequently, ecosystem functions. Vegetation spatial patterns in fire-excluded forested landscapes no longer reflect the heterogeneity maintained by interacting fires of active fire regimes. Live and dead vegetation (surface and canopy fuels) is generally more abundant and continuous than before European colonization. As a result, current conditions are more vulnerable to the direct and indirect effects of seasonal and episodic increases in drought and fire, especially under a rapidly warming climate. Long-term fire exclusion and contemporaneous social-ecological influences continue to extensively modify seasonally dry forested landscapes. Management that realigns or adapts fire-excluded conditions to seasonal and episodic increases in drought and fire can moderate ecosystem transitions as forests and human communities adapt to changing climatic and disturbance regimes. As adaptation strategies are developed, evaluated, and implemented, objective scientific evaluation of ongoing research and monitoring can aid differentiation of warranted and unwarranted uncertainties.
Mn2+-doped ZnSe quantum dots (Mn:ZnSe d-dots) with a tunable photoluminescence (PL) peak position were made to be water soluble by coating them with a monolayer of mercaptopropionic acid, a very ...short hydrophilic thiol. If the dopant centers were located close to the surface, thiol-coating partially quenched the PL. With about 2−3 monolayers of pure ZnSe on the surface, the PL of d-dots was actually enhanced upon thiol coating. When the doping centers were placed reasonably inside a d-dot, with about four monolayers of pure ZnSe between the doping centers and the surface ligands, the thiol ligands did not quench the PL of the d-dots, even though they did completely quench the PL of intrinsic ZnSe quantum dots. The overall size of such d-dots/ligand complex is only about 7−8 nm, implying an excellent permeability in biological issues. These d-dots were found to be exceptionally stable against continuous UV radiation in air for at least 25 days. They were also stable in boiling water with air bubbling under room light for hours. Recognition of a biotin pattern by d-dots conjugated with avidine was carried to illustrate the suitability of these efficient (about 40% PL quantum yield), stable, small, and water-soluble d-dots as biomedical labeling reagents.
The ability to distinguish peatland types at the landscape scale has implications for inventory, conservation, estimation of carbon storage, fuel loading, and postfire carbon emissions, among others. ...This paper presents a multisensor, multiseason remote sensing approach to delineate boreal peatland types (wooded bog, open fen, shrubby fen, treed fen) using a combination of multiple dates of L-band (24 cm) synthetic aperture radar (SAR) from ALOS PALSAR, C-band (∼5.6 cm) from ERS-1 or ERS-2, and Landsat 5 TM optical remote sensing data. Imagery was first evaluated over a small test area of boreal Alberta, Canada, to determine the feasibility of using multisensor SAR and optical data to discriminate peatland types. Then object-based and (or) machine-learning classification algorithms were applied to 3.4 million ha of peatland-rich subregions of Alberta, Canada, and the 4.24 million ha region of Michigan’s Upper Peninsula where peatlands are less dominant. Accuracy assessments based on field-sampled sites show high overall map accuracies (93%–94% for Alberta and Michigan), which exceed those of previous mapping efforts.
Microplastics' (MPs) abundance, small size, and global distribution render them bioavailable to a variety of organisms directly or by trophic transfer, yet examinations in marine apex predators are ...currently limited. The present study investigated the occurrence of MPs sized 125 μm–5 mm in the gastrointestinal tract (GIT) of bottlenose dolphins (Tursiops truncatus) stranded in South Carolina, USA from 2017 to 2018. MPs, mostly fibers, were detected in all GITs (n = 7) of stranded bottlenose dolphins. Total suspected MPs ranged between 123 and 422 particles/individual, a high range among international studies. Comparison to other studies likely reflects differences in both methods and location. This is the first study from North America to quantify MPs in a small coastal cetacean outside Arctic waters and the first specifically in bottlenose dolphins (southeastern United States). Findings and methodology from this investigation can aid future studies examining MP in marine apex predators.
•Microplastics in all 7 gastrointestinal tracts of bottlenose dolphins examined•Microplastics may fragment in cetacean digestive tract.•Fibers dominant morphology observed; fragments, films, and foams also present•Comparison to other studies likely reflects differences in methods and location.•Pathways of exposure and potential impacts on dolphins are still poorly understood.
This review surveys the statistics of solar X-ray flares, emphasising the new views that
RHESSI
has given us of the weaker events (the microflares). The new data reveal that these microflares ...strongly resemble more energetic events in most respects; they occur solely within active regions and exhibit high-temperature/nonthermal emissions in approximately the same proportion as major events. We discuss the distributions of flare parameters (e.g., peak flux) and how these parameters correlate, for instance via the Neupert effect. We also highlight the systematic biases involved in intercomparing data representing many decades of event magnitude. The intermittency of the flare/microflare occurrence, both in space and in time, argues that these discrete events do not explain general coronal heating, either in active regions or in the quiet Sun.