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bstract
One proposed component of the upcoming Deep Underground Neutrino Experiment (DUNE) near detector complex is a multi-purpose, magnetized, gaseous argon time projection chamber: the ...Multi-Purpose Detector (MPD). We explore the new-physics potential of the MPD, focusing on scenarios in which the MPD is significantly more sensitive to new physics than a liquid argon detector, specifically searches for semi-long-lived particles that are produced in/near the beam target and decay in the MPD. The specific physics possibilities studied are searches for dark vector bosons mixing kinetically with the Standard Model hypercharge group, leptophilic vector bosons, dark scalars mixing with the Standard Model Higgs boson, and heavy neutral leptons that mix with the Standard Model neutrinos. We demonstrate that the MPD can extend existing bounds in most of these scenarios. We illustrate how the ability of the MPD to measure the momentum and charge of the final state particles leads to these bounds.
Deep understanding of the structure–property relationships of polysaccharide derivatives depends on the ability to control the position of the substituents around the monosaccharide ring and along ...the chain. Equally important is the ability to analyze position of substitution. Historically, both synthetic control and analysis of regiochemistry have been very difficult for cellulose derivatives, as for most other polysaccharide derivatives. With the advent of cellulose solvents that are suitable for chemical transformations, it has become possible to carry out cellulose derivatization under conditions sufficiently mild to permit increasingly complete regiochemical control, particularly with regard to the position of the substituents around the anhydroglucose ring. In addition, new techniques for forming cellulose and its derivatives from monomers, either by enzyme-catalyzed processes or chemical polymerization, permit us to address new frontiers in regiochemical control. We review these exciting developments in regiocontrolled synthesis of cellulose derivatives and their implications for in-depth structure–property studies.
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IJS, KILJ, NUK, PNG, UL, UM
A
bstract
We present dark tridents, a new channel for exploring dark sectors in short-baseline neutrino experiments. Dark tridents are clean, distinct events where, like neutrino tridents, the ...scattering of a very weakly coupled particle leads to the production of a lepton-antilepton pair. Dark trident production occurs in models where long-lived dark-sector particles are produced along with the neutrinos in a beam-dump environment and interact with neutrino detectors downstream, producing an on-shell boson which decays into a pair of charged leptons. We focus on a simple model where the dark matter particle interacts with the standard model exclusively through a dark photon, and concentrate on the region of parameter space where the dark photon mass is smaller than twice that of the dark matter particle and hence decays exclusively into standard-model particles. We compute event rates and discuss search strategies for dark tridents from dark matter at the current and upcoming liquid argon detectors aligned with the Booster beam at Fermilab — MicroBooNE, SBND, and ICARUS — assuming the dark sector particles are produced off-axis in the higher energy NuMI beam. We find that MicroBooNE has already recorded enough data to be competitive with existing bounds on this dark sector model, and that new regions of parameter space will be probed with future data and experiments.
Nonzero neutrino masses imply the existence of degrees of freedom and interactions beyond those in the Standard Model. A powerful indicator of what these might be is the nature of the massive ...neutrinos: Dirac fermions versus Majorana fermions. While addressing the nature of neutrinos is often associated with searches for lepton-number violation, there are several other features that distinguish Majorana from Dirac fermions. Here, we compute in great detail the kinematics of the daughters of the decays into charged-leptons and neutrinos of hypothetical heavy neutral leptons at rest. We allow for the decay to be mediated by the most general four-fermion interaction Lagrangian. We demonstrate, for example, that when the daughter charged-leptons have the same flavor or the detector is insensitive to their charges, polarized Majorana-fermion decays have zero forward-backward asymmetry in the direction of the outgoing neutrino (relative to the parent spin), whereas Dirac-fermion decays can have large asymmetries. Going beyond studying forward-backward asymmetries, we also explore the fully differential width of the three-body decays. It contains a wealth of information not only about the nature of the new fermions but also the nature of the interactions behind their decays.
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CMK, CTK, FMFMET, IJS, NUK, PNG, UM
Rare meson decays are among the most sensitive probes of both heavy and light new physics. Among them, new physics searches using kaons benefit from their small total decay widths and the ...availability of very large datasets. On the other hand, useful complementary information is provided by hyperon decay measurements. We summarize the relevant phenomenological models and the status of the searches in a comprehensive list of kaon and hyperon decay channels. We identify new search strategies for under-explored signatures, and demonstrate that the improved sensitivities from current and next-generation experiments could lead to a qualitative leap in the exploration of light dark sectors.
•General theoretical framework for decomposing productivity growth is provided.•Uses nonparametric reference technologies without convexity assumptions.•Technical efficiency, technical change and ...returns to scale measures are defined.•Justification given for the geometric mean form of the Bjurek productivity index.
Productivity measures are increasingly regarded as key indicators of economic performance. Identifying sources of productivity growth is of interest to both firms and policy makers. This paper revisits the debate on how to decompose productivity growth into explanatory factors, with a focus on extracting technical progress, technical efficiency change, and returns to scale components. Using Bjurek's concept of the Malmquist index, introduced into production theory in a systematic way by Caves, Christensen and Diewert, a reference technology is required to define the components of interest. Unlike other approaches, ours do not make any convexity assumptions on the reference technology but instead follows the example of Tulkens and his coauthors in assuming that the reference technology satisfies free disposability assumptions. A new decomposition of a productivity index is provided, with the existence and properties of the underlying distance functions of the decomposition proven under relatively unrestrictive assumptions. The paper also provides for the first time a theoretical justification for the geometric average form of the Bjurek productivity index. These rigorous theoretical contributions provide significant avenues for enhanced understanding of empirical productivity performance.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Summary
Macrophysiology is the investigation of variation in physiological traits over large geographic and temporal scales and the ecological implications of this variation. It has now been ...undertaken, as a defined field, for a decade.
Here, we overview its conceptual foundations, methodological approaches and insights, together with challenges the field is facing currently.
Macrophysiology builds on approaches that investigate the ecological and evolutionary significance of physiological trait variation and feedbacks in these processes. One of its key strengths is its ability to provide a basis for examining interactions among the intraspecific, interspecific and assemblage levels.
Macrophysiology is distinct from and typically concerns larger spatial and temporal scales than conservation physiology, whereas it is in several respects similar to, but antecedes, functional biogeography. Contrary to some claims, macrophysiology is not concerned only with the implications for geographic ranges of physiological trait variation.
Several insights, which would not otherwise have been achieved, have arisen from the field, notably the understanding of variation in global patterns of upper and lower lethal temperature limits and organism performance, which have important implications for forecasting the impacts of climate change.
Ten major challenges are identified for the field of macroecology, including better integration of approaches and information for plants and animals. Nonetheless, the prospects for macrophysiology as a significant way to understand our world remain bright.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NMLJ, NUK, OILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK
Although increased temperatures are known to reinforce the effects of habitat destruction at local to landscape scales, evidence of their additive or interactive effects is limited, particularly over ...larger spatial extents and longer timescales. To address these deficiencies, we created a dataset of land-use changes over 75 years, documenting the loss of over half (>3000 km
) the semi-natural grassland of Great Britain. Pairing this dataset with climate change data, we tested for relationships to distribution changes in birds, butterflies, macromoths, and plants (n = 1192 species total). We show that individual or additive effects of climate warming and land conversion unambiguously increased persistence probability for 40% of species, and decreased it for 12%, and these effects were reflected in both range contractions and expansions. Interactive effects were relatively rare, being detected in less than 1 in 5 species, and their overall effect on extinction risk was often weak. Such individualistic responses emphasise the importance of including species-level information in policies targeting biodiversity and climate adaptation.
Dark fluxes from electromagnetic cascades Blinov, Nikita; Fox, Patrick J.; Kelly, Kevin J. ...
The journal of high energy physics,
3/7, Volume:
2024, Issue:
7
Journal Article
Peer reviewed
Open access
A
bstract
We study dark sector production in electromagnetic (EM) cascades. This problem requires accurate simulations of Standard Model (SM) and dark sector processes, both of which impact angular ...and energy distributions of emitted particles that ultimately determine flux predictions in a downstream detector. We describe the minimal set of QED processes which must be included to faithfully reproduce a SM cascade, and identify a universal algorithm to generate a dark sector flux given a Monte-Carlo simulation of a SM shower. We provide a new tool,
, which simulates EM cascades with associated dark vector production, and compare it against existing literature and “off the shelf” tools. The signal predictions at downstream detectors can strongly depend on the nontrivial interplay (and modelling) of SM and dark sector processes, in particular multiple Coulomb scattering and positron annihilation. We comment on potential impacts of these effects for realistic experimental setups.
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