Minimal Scenario Research Articles

Cosmic stability of dark matter from Pauli blocking

Why does dark matter (DM) live longer than the age of the Universe? Here we study a novel sub-eV scalar DM candidate whose stability is due to the Pauli exclusion of its fermionic decay products. We analyze the stability of the DM condensate against decays, scatterings (i.e., evaporation), and parametric resonance, delineating the viable parameter regions in which DM is cosmologically stable. In a minimal scenario in which the scalar DM decays to a pair of new exotic fermions, we find that scattering can populate an interacting thermal dark sector component to energies far above the DM mass. This self-interacting dark radiation may potentially alleviate the Hubble tensions. Furthermore, our scenario can be probed through precise measurements of the halo-mass function or the masses of dwarf spheroidal galaxies since scattering prevents the DM from becoming too dense. On the other hand, if the lightest neutrino stabilizes the DM, the cosmic neutrino background (CνB) can be significantly altered from the Lambda cold dark matter prediction and thus be probed in the future by CνB detection experiments. Published by the American Physical Society 2024

Array analysis of P-wave polarization data for constraining near-surface shear wave speeds: Aplication to theValley of Mexico seismic network

SUMMARY We present an array method for constraining near-surface shear wave speed values from P-wave polarization data. As the direction of P-wave particle motion is determined both by the incident ray parameter and the local surficial shear wave speed, the latter can be inferred from three-component seismic records if the ray parameter is estimated first. Previous studies have analysed data recorded at a single station from various earthquakes in order to estimate near-surface shear wave speed. In contrast, this paper analyses data recorded at an array of stations. As such, this method can estimate both ray parameter data for the recorded earthquakes and near-surface shear wave speed values at the studied sites. And as an advantage, the method can analyse records of local and regional earthquakes where ray parameter information cannot be reliably estimated using 1D reference velocity models. Additionally, by processing polarization data spanning multiple events and stations, our method provides robust estimates for near-surface shear wave speed values. We apply this array-based method to a seismic array covering the Valley of Mexico. Analysed records correspond to regional earthquakes with epicentral distances of roughly 300 km. The corresponding ray parameter values for all earthquakes were estimated from the delay of the seismic waves arrival throughout the network as all stations have a reliable time reference. Near-surface shear wave speed values estimated from the array-based polarization analysis are correlated with major geological features of the area such as the Trans-Mexican Volcanic Belt and the local basin. We also apply the presented method to a minimal data scenario. The flexibility of this method allows it to employ a single ray parameter value as input, producing robust estimates for near-surface shear wave speed values within our case study. This feature becomes useful in a variety of scenarios, such as utilizing seismic data lacking timing information. The presented method constitutes an accessible and inexpensive alternative to study shallow seismic structure, opening opportunities to expand and complement current tools and techniques to assess seismic hazards.

Association of the IceCube neutrinos with blazars in the CGRaBS sample

The origin of high-energy (HE) astrophysical neutrinos has remained an elusive hot topic in the field of HE astrophysics for the past decade. Apart from a handful of individual associations, the vast majority of HE neutrinos arise from unknown sources. While there are theoretically motivated candidate populations, such as blazars – a subclass of active galactic nuclei with jets pointed toward our line of sight – they have not been convincingly linked to HE neutrino production yet. Here, we perform a spatio-temporal association analysis between a sample of blazars (from the CGRaBS catalog) in the radio and optical bands and the most up-to-date IceCube HE neutrino catalog. We find that if the IceCube error regions are enlarged by 1° in quadrature, to account for unknown systematic errors at a maximal level, a spatio-temporal correlation between the multiwavelength light curves of the CGRaBS blazars and the IceCube HE neutrinos is hinted at, least at a 2.17σ significance level. On the other hand, when the IceCube error regions are taken as their published values, we do not find any significant correlations. A discrepancy in the blazar-neutrino correlation strengths, when using such minimal and enlarged error region scenarios, was also obtained in a recent study by the IceCube collaboration. In our study, this difference arises because several flaring blazars – coinciding with a neutrino arrival time – happen to narrowly miss the published 90%-likelihood error region of the nearest neutrino event. For all of the associations driving our most significant correlations, the flaring blazar is much less than 1° away from the published error regions. Therefore, our results indicate that the question of the blazar-neutrino connection is highly sensitive to the reconstruction of the neutrino error regions, whose reliability is expected to improve with the next generation of neutrino observatories.

The motion of twisted particles in a stellar gravitational field

Abstract In this work, we explore the motion of a twisted particle possessing intrinsic orbital angular momentum (OAM) as it traverses a weak stellar gravitational field, which we approximate using a polytropic model. We disregard the spin characteristic of the twisted particle, modeling it as a massless complex twisted scalar wave packet to simplify its interaction with gravitational fields. Building on this simplification, we determine the trajectory of this twisted particle by using the center of its energy density and investigate the gravitational birefringence induced by its OAM. In a weak field approximation, we find the gravitational birefringence-OAM relationship parallels that with spin, as described by the Mathisson-Papapetrou-Dixon equations. This indicates that the gravitational birefringence induced by OAM can potentially exceed that induced by spin by several orders of magnitude, significantly enhancing its detectability. To broaden our analysis, we introduce a nonminimal coupling term, $\lambda R|\phi|^2$, into the Lagrangian, resulting in the modified expression $\mathcal{L}=-\frac{1}{2}\nabla _\rho\phi\nabla^\rho\phi^*-\frac{1}{2}\lambda R|\phi|^2$. This adjustment is necessitated by the quantization of the scalar field in curved spacetime. We then explore the effects of this term on the motion of the twisted particle. Our findings show that the trajectory of the twisted particle under nonminimal coupling ($\lambda\neq 0$) differs from that in the minimal coupling scenario ($\lambda=0$). Specifically, for a positive nonminimal coupling constant $\lambda$, the trajectory of the twisted particle is expected to deviate away from the stellar center, compared to the minimal coupling scenario.

A novel framework for integrating environmental costs and carbon pricing in open-pit mine plans: Towards sustainable and green mining

As the worldwide need for mineral resources continues to grow, there is an increasing emphasis on mitigation of the environmental consequences of the mining sector, necessitating a shift towards sustainable and green mining practices. This paradigm requires the meticulous integration of environmental considerations throughout all stages of planning and operation in open-pit mining. Therefore, this research introduces an innovative integrated framework for long-term mine planning, strategically combining economic and environmental considerations in open-pit mining operations. The methodology integrates carbon pricing into the decision-making process, addressing potential financial risks and introducing two distinct scenarios: one focused on minimizing environmental costs and the other on maximizing adjusted Net Present Value (NPV). The application of this integrated framework to an open-pit iron mine in the Middle East region yielded insightful results. The integrated framework's impact on block sequencing, greenhouse gas emissions, and financial outcomes was assessed, highlighting the divergent strategies employed in the two scenarios. The minimization scenario demonstrated it was feasible to attain 90.54% of the global warming impact and 90.48% of environmental costs while achieving 96.25% of the adjusted NPV compared to the maximization scenario. Sensitivity analyses further underscored the adaptability of the framework to varying carbon pricing scenarios. This research validates a sustainable approach to mine planning, emphasizing a balance between economic returns and ecological responsibility, and provides valuable insights for decision-makers in the mining industry.

Techno‐Economic Modeling of Diverse Renewable Energy Sources Integration: Achieving Net‐Zero CO2 Emissions

Integrating renewable energy sources (RES) into power systems presents significant challenges due to their diverse nature and operational characteristics. This study addresses these challenges through an innovative strategy that simulates solar and wind farms, storage systems, fuel cell generators of hydrogen energy (via electrolysis), and hydrogen storage, all governed by an intelligent controller. Alongside a mathematical model defining the system's dynamics, a multi‐objective optimization model is employed, exploring the system's operational, financial, and environmental impacts. While the mathematical model has limitations, the advanced model captures the system's dynamic behavior with exceptional precision. This intelligent simulation simplifies the complex interrelationships between various resources in the system, highlighting the viability of RES integration for enhanced benefits. Multi‐objective optimization of a real case study of Iowa 240‐Bus power system in the Midwest United States has resulted in an annual savings of $126 147.8, along with a significant CO2 reduction of 951 035.6 kg compared with the basecase. The total annual energy costs, including capital costs and electricity sales, are reported to be $157 430.4, and the total annual CO2 emissions are −4453.8 kg. Financial indicators highlight an annual cost reduction of 10.3% and an annual emission reduction of 100.5%. The simple and detailed project break‐even years are 18 and 1, respectively, with the project savings to cost minimization scenario ratio at 1.04. The optimization process efficiently handled a complex problem involving 5921 iterations, 299 247 variables, 11 854 discrete variables, and 342 167 equations, completing the entire operation in 12.7 s. © 2024 Institute of Electrical Engineers of Japan and Wiley Periodicals LLC.

Post-quantum nonlocality in the minimal triangle scenario

We investigate network nonlocality in the triangle scenario when all three parties have no input and binary outputs. Through an explicit example, we prove that this minimal scenario supports nonlocal correlations compatible with no-signaling and independence of the three sources, but not with realisations based on independent quantum or classical sources. This nonlocality is robust to noise. Moreover, we identify the equivalent to a Popescu-Rohrlich box in the minimal triangle scenario.

The flavor of a light charged Higgs

The ATLAS Collaboration has recently reported a search for light-charged Higgs in t → H+b decay, with {H}^{+}to coverline{b} . An excess with a local significance of approximately 3σ is found at {m}_{H^{+}} ≈ 130 GeV, with a best-fit value of BR(t → H+b) × BR( {H}^{+}to coverline{b} ) = (1.6 ± 0.6) × 10−3. We study the implications of such a hypothetical signal in multi-Higgs doublet models. We take into account constraints from searches for other charged Higgs decays and from flavor-changing neutral current processes. Two Higgs doublet models with flavor structure dictated by natural flavor conservation (NFC), minimal flavor violation (MFV), or the Froggatt-Nielsen (FN) mechanism cannot account for such excess. A three-Higgs doublet model with NFC can account for the signal. The Yukawa couplings of the neutral pseudoscalar A in the down sector, {hat{Y}}_A^D , should be larger by a factor of 4 – 6 compared to the corresponding Yukawa couplings of the Higgs h, {hat{Y}}_h^D . We further present two minimal scenarios, one in which a single Yukawa coupling in the down sector, {left({hat{Y}}_A^Dright)}_{bb} , gives the only significant contribution, and one in which two Yukawa couplings in the up sector, {left({hat{Y}}_A^Uright)}_{tt} and {left({hat{Y}}_A^Uright)}_{tc} , give the only significant contributions, and we discuss possible tests of these scenarios.

Managing for biodiversity: The effects of climate, management and natural disturbance on wildlife species richness

AbstractAimManagers are increasingly facing an uncertain future given changing climates and ecological trajectories. The interacting effects of climate, natural disturbance, and management actions complicate future projections, and there is a need for approaches that integrate these factors—especially for predicting future vegetation and species richness.LocationCentral Sierra Nevada Mountains, USA.MethodsWe used outputs from a spatially explicit landscape disturbance succession model that incorporated forest management actions, disturbance, and climate to estimate habitat and potential species richness for 202 vertebrate species and five functional groups from 2020 to 2100. We examined species richness outcomes of three forest management scenarios under three climate trajectories. We modelled broadscale drivers of landscape‐level species richness, and proximate effects of management and disturbance at each pixel.ResultsClimate and forest management scenario had significant effects on potential species richness across the landscape, particularly at lower elevations; however, only management had significant effects at higher elevations. We found no effect of the interaction between climate and management scenario. The historical climate and the minimal management scenario generally resulted in higher species richness compared with other scenarios. Positive proximate effects generally included mechanical thinning and prescribed fire, as well as low and medium severity fire and beetle outbreaks. High severity fire had a consistently negative effect on species richness. We also quantified the contribution of protected areas and found that protected areas had higher species richness compared with ecologically similar unprotected lands, especially in climate futures that deviated from the historical climate.Main ConclusionsOur findings highlight that managing for biodiversity is complex, and effects of climate, disturbance, and management differ among species, functional groups, topography and scales. However, landscape disturbance succession models provide a science‐based tool for untangling broadscale drivers and proximate effects of biodiversity and managing for ecological integrity in a changing climate.

Technical and economic assessment of a hybrid heat pump system as an energy retrofit measure in a residential building

Air to water electric heat pumps are one technological solution to achieve energy defossilisation goals for heating of residential building stock. Nevertheless, they may not necessarily be the only solution for all residential building stock. A case in point is where extensive fabric refurbishment is impracticable or where electric heat pumps are installed where low ambient temperatures prevail and/or high water delivery temperatures must be utilised. For such instances, hybrid (gas and electric) heat pumps offer an alternative option by facilitating fuel source switching between electricity and gas, when ambient temperatures are low or high water supply temperatures are required. In the current study, the effectiveness of an air-to-water electric heat pump and hybrid heat pump are examined for different building retrofit scenarios for a residential dwelling located in Ireland. This is achieved by means of a sensitivity study of a validated building simulation model, incorporating both heat pump systems, subject to different building retrofit scenarios. Relative to a conventional oil-fired boiler, for a deep building retrofit scenario, the hybrid and electric heat pumps achieve primary energy savings of 73% and 70%, respectively. For a minimal building retrofit scenario, the respective primary energy savings are 57% and 52%. For the deep retrofit scenario, compared to the baseline building with no retrofit measures, the carbon footprint reductions were found to be (8.5 gCO2e/m2/year or 44%) for the hybrid heat pump, (10.31 gCO2e/m2/year or 45%) for the electric heat pump, and (17-21 gCO2e/m2/year or 43-53%) for oil or gas boiler systems. Finally, the deployment of either an electric heat pump or hybrid heat pump for deep building fabric retrofit achieves approximately half heating system capital cost return within 20 years.

Bounds on lepton non-unitarity and heavy neutrino mixing

We present an updated and improved global fit analysis of current flavour and electroweak precision observables to derive bounds on unitarity deviations of the leptonic mixing matrix and on the mixing of heavy neutrinos with the active flavours. This new analysis is motivated by new and updated experimental results on key observables such as Vud, the invisible decay width of the Z boson and the W boson mass. It also improves upon previous studies by considering the full correlations among the different observables and explicitly calibrating the test statistic, which may present significant deviations from a χ2 distribution. The results are provided for three different Type-I seesaw scenarios: the minimal scenario with only two additional right-handed neutrinos, the next to minimal one with three extra neutrinos, and the most general one with an arbitrary number of heavy neutrinos that we parametrise via a generic deviation from a unitary leptonic mixing matrix. Additionally, we also analyze the case of generic deviations from unitarity of the leptonic mixing matrix, not necessarily induced by the presence of additional neutrinos. This last case relaxes some correlations among the parameters and is able to provide a better fit to the data. Nevertheless, inducing only leptonic unitarity deviations avoiding both the correlations implied by the right-handed neutrino extension as well as more strongly constrained operators is challenging and would imply significantly more complex UV completions.

Searches for additional Higgs bosons and for vector leptoquarks in ττ final states in proton-proton collisions at sqrt{s} = 13 TeV

Three searches are presented for signatures of physics beyond the standard model (SM) in ττ final states in proton-proton collisions at the LHC, using a data sample collected with the CMS detector at sqrt{s} = 13 TeV, corresponding to an integrated luminosity of 138 fb−1. Upper limits at 95% confidence level (CL) are set on the products of the branching fraction for the decay into τ leptons and the cross sections for the production of a new boson ϕ, in addition to the H(125) boson, via gluon fusion (ggϕ) or in association with b quarks, ranging from mathcal{O} (10 pb) for a mass of 60 GeV to 0.3 fb for a mass of 3.5 TeV each. The data reveal two excesses for ggϕ production with local p-values equivalent to about three standard deviations at mϕ = 0.1 and 1.2 TeV. In a search for t-channel exchange of a vector leptoquark U1, 95% CL upper limits are set on the dimensionless U1 leptoquark coupling to quarks and τ leptons ranging from 1 for a mass of 1 TeV to 6 for a mass of 5 TeV, depending on the scenario. In the interpretations of the {M}_{textrm{h}}^{125} and {M}_{textrm{h},textrm{EFT}}^{125} minimal supersymmetric SM benchmark scenarios, additional Higgs bosons with masses below 350 GeV are excluded at 95% CL.

Tri-bimaximal-Cabibbo mixing: flavour violations in the charged lepton sector

The well understood structure of U_{pmns} matrix mandates a Cabibbo mixing matrix in the first two generations of the charged lepton sector if we assume Tri-bimaximal mixing in the neutrino sector. This ansatz, called Tri-bimaximal-Cabibbo mixing, is ruled out immediately by the experiments searching for charged lepton flavour violating currents. In this article, we aim to show that the resurrection of the theoretically well motivated Tri-bimaximal mixing scenario comes naturally within Minimal Flavour Violation hypothesis in the lepton sector. We analyse the flavour violating currents mu rightarrow e e e, mu Ti rightarrow e Ti, mu rightarrow e gamma , pi ^0rightarrow e^+ mu ^{-} and K_L rightarrow mu ^+ e^- in this scenario and show that the New Physics that generates mixing among the charged lepton could lie within the reach of hadron colliders. In the minimal field content scenario, though the most stringent constrain on New Physics is gtrsim {mathcal {O}}(10 TeV) for maximal coupling, considering more natural couplings relaxes it to gtrsim {mathcal {O}}(4 TeV). On the other hand, New Physics with the extended field content is even more strongly constrained to gtrsim {mathcal {O}}(75 TeV) for maximal coupling, while it gets relaxed to gtrsim {mathcal {O}}(31 TeV) for natural scenario.

A graph-based approach for minimising the knowledge requirement of explainable recommender systems

Traditionally, recommender systems use collaborative filtering or content-based approaches based on ratings and item descriptions. However, this information is unavailable in many domains and applications, and recommender systems can only tackle the problem using information about interactions or implicit knowledge. Within this scenario, this work proposes a novel approach based on link prediction techniques over graph structures that exclusively considers interactions between users and items to provide recommendations. We present and evaluate two alternative recommendation methods: one item-based and one user-based that apply the edge weight, common neighbours, Jaccard neighbours, Adar/Adamic, and Preferential Attachment link prediction techniques. This approach has two significant advantages, which are the novelty of our proposal. First, it is suitable for minimal knowledge scenarios where explicit data such as ratings or preferences are not available. However, as our evaluation demonstrates, this approach outperforms state-of-the-art techniques using a similar level of interaction knowledge. Second, our approach has another relevant feature regarding one of the most significant concerns in current artificial intelligence research: the recommendation methods presented in this paper are easily interpretable for the users, improving their trust in the recommendations.

Higgsino Dark Matter Confronts 14Years of Fermi γ-Ray Data.

Thermal Higgsino dark matter (DM), with mass around 1TeV, is a well-motivated, minimal DM scenario that arises in supersymmetric extensions of the standard model. Higgsinos may naturally be the lightest superpartners in split-supersymmetry models that decouple the scalar superpartners while keeping Higgsinos and gauginos close to the TeV scale. Higgsino DM may annihilate today to give continuum γ-ray emission at energies less than a TeV in addition to a linelike signature at energies equal to the mass. Previous searches for Higgsino DM, for example with the H.E.S.S. γ-ray telescope, have not reached the necessary sensitivity to probe the Higgsino annihilation cross section. In this work we make use of 14years of data from the Fermi Large Area Telescope at energies above ∼10 GeV to search for the continuum emission near the Galactic Center from Higgsino annihilation. We interpret our results using DM profiles from MilkyWay analog galaxies in the FIRE-2 hydrodynamic cosmological simulations. We set the strongest constraints to date on Higgsino-like DM. Our results show a mild, ∼2σ preference for Higgsino DM with a mass near the thermal Higgsino mass and, depending on the DM density profile, the expected cross section.

МЕТАФОРИЧКА КОНЦЕПТУАЛИЗАЦИЈА ПАМЋЕЊА КОД ГОВОРНИКА ЕНГЛЕСКОГ И СРПСКОГ ЈЕЗИКА

The present paper reports on the findings regarding the metaphorical conceptualization of memory as one of the higher mental processes that comprise the mind. The research is grounded in Conceptual Metaphor Theory, and the data is compiled from Serbian and English newspapers. By analyzing the metaphorical linguistic expressions, we seek to: a) determine the scope of source domains that structure the given cognitive process, b) formulate the underlying conceptual metaphors, and c) compare the results between the two languages in order to test the universality of memory metaphors. We hope that such approach would highlight the way speakers of each language conceptualize this domain. We have managed to identify several source domains and conceptual metaphors that have been overlooked in previous studies, which indicates that the dominant “minimal memory scenario”, which was believed to be comprised primarily of the spatial storage and search metaphors, is but one way of understanding memory.

Light scalar explanation for the 18 TeV GRB 221009A

Recent astrophysical transient Swift J1913.1+1946 may be associated with the $\gamma$-ray burst GRB 221009A. The redshift of this event is $z\simeq 0.151$. Very high-energy $\gamma$-rays (up to 18 TeV) followed the transient and were observed by LHAASO, additionally Carpet-2 detected a photon-like air shower of 251 TeV. Photons of such high energy are expected to readily annihilate with the diffuse extragalactic background light (EBL) before reaching Earth. If the $\gamma$-ray identification and redshift measurements are correct, new physics could be necessary to explain these measurements. This letter provides the first CP-even scalar explanation of the most energetic 18 TeV event reported by LHAASO. In this minimal scenario, the light scalar singlet $S$ mixes with the Standard Model (SM) Higgs boson $h$. The highly boosted $S$ particles are produced in the GRB and then undergo the radiative decay di-photon $S\rightarrow \gamma\gamma$ while propagating to Earth. The resulting photons may thus be produced at a remote region without being nullified by the EBL. Hence, the usual exponential reduction of $\gamma$-rays is lifted due to an attenuation that is inverse in the optical depth, which becomes much larger due to the scalar carriers.

Minimal Zee model for lepton g−2 and W -mass shifts

We present a unique Yukawa structure of the Zee model that can accommodate neutrino oscillation data, solves the muon ${g-2}$ problem, and explains the recent $W$ boson mass measurement. Our Yukawa structure is minimal in the sense that it contains the least possible number of parameters. In this minimal scenario, neutrino masses are quasidegenerate and are compatible with both normal and inverted orderings. The mixing angle $\theta_{23}$ is predicted to lie in the second (first) octant for normal (inverted) ordering. In both cases, the CP violating phase is close to 3$\pi/2$. The minimal texture also predicts a large branching fraction of the heavy neutral Higgs boson into a pair of electron and muon.

Quantum Correlations in the Minimal Scenario

In the minimal scenario of quantum correlations, two parties can choose from two observables with two possible outcomes each. Probabilities are specified by four marginals and four correlations. The resulting four-dimensional convex body of correlations, denoted Q, is fundamental for quantum information theory. We review and systematize what is known about Q, and add many details, visualizations, and complete proofs. In particular, we provide a detailed description of the boundary, which consists of three-dimensional faces isomorphic to elliptopes and sextic algebraic manifolds of exposed extreme points. These patches are separated by cubic surfaces of non-exposed extreme points. We provide a trigonometric parametrization of all extreme points, along with their exposing Tsirelson inequalities and quantum models. All non-classical extreme points (exposed or not) are self-testing, i.e., realized by an essentially unique quantum model.Two principles, which are specific to the minimal scenario, allow a quick and complete overview: The first is the pushout transformation, i.e., the application of the sine function to each coordinate. This transforms the classical correlation polytope exactly into the correlation body Q, also identifying the boundary structures. The second principle, self-duality, is an isomorphism between Q and its polar dual, i.e., the set of affine inequalities satisfied by all quantum correlations (“Tsirelson inequalities''). The same isomorphism links the polytope of classical correlations contained in Q to the polytope of no-signalling correlations, which contains Q.We also discuss the sets of correlations achieved with fixed Hilbert space dimension, fixed state or fixed observables, and establish a new non-linear inequality for Q involving the determinant of the correlation matrix.

Neutrino origin of LHAASO's 18 TeV GRB221009A photon

LHAASO collaboration detected photons with energy above 10 TeV from the most recent gamma-ray burst (GRB), GRB221009A. Given the redshift of this event, z∼0.15, photons of such energy are expected to interact with the diffuse extragalactic background light (EBL) well before reaching Earth. In this paper we provide a novel neutrino-related explanation of the most energetic 18 TeV event reported by LHAASO. We find that the minimal viable scenario involves both mixing and transition magnetic moment portal between light and sterile neutrinos. The production of sterile neutrinos occurs efficiently via mixing while the transition magnetic moment portal governs the decay rate in the parameter space where tree-level decays via mixing to non-photon final states are suppressed. Our explanation of this event, while being consistent with the terrestrial constraints, points to the non-standard cosmology.