Standard Theoretical Model Research Articles

B→D* and Bs→Ds* vector, axial-vector and tensor form factors for the full q2 range from lattice QCD

We compute the complete set of Standard Model (SM) and tensor B→D*ℓν¯ and Bs→Ds*ℓν¯ semileptonic form factors across the full kinematic range of the decays using second generation MILC nf=2+1+1 highly improved staggered quark (HISQ) gluon field configurations and HISQ valence quarks, with the method. Lattice spacings range from 0.09 to 0.044 fm with pion masses from ≈300 MeV down to the physical value and heavy quark masses ranging between ≈1.5mc and 4.1mc≈0.9mb; currents are normalized nonperturbatively. Using the recent untagged B→D*ℓν¯ℓ data from Belle and Bs→Ds*μν¯μ from LHCb together with our form factors, we determine a model independent value of Vcb=39.03(56)exp(67)latt×10−3, in agreement with previous exclusive determinations and in tension with the most recent inclusive result at the level of 3.6σ. We also observe a ≈1σ tension between the shape of the differential decay rates computed using our form factors and those measured by Belle. We compute a purely theoretical Standard Model value for the ratio of semitauonic and semimuonic decay rates, R(D*)=0.273(15), which we find to be closer to the recent Belle measurement and heavy flavor averaging group average than theory predictions using fits to experimental differential rate data for B→D*ℓν¯ℓ. Determining Vcb from our form factors and the experimental total rate for B→D*ℓν also gives a value in agreement with inclusive results. We also compute the longitudinal polarization fraction for the semitauonic mode, FLD*=0.395(24), which is in tension at the level of 2.2σ with the recent Belle measurement. Our calculation combines B→D* and Bs→Ds* lattice results in a simultaneous chiral continuum extrapolation, maintaining correlations between both modes. We then give results for both B→D* and Bs→Ds*, with the Bs→Ds* results superseding our previous lattice computation. We also give the chiral perturbation theory needed to analyze the tensor form factors. Published by the American Physical Society 2024

One’s Own and Foreign in Context of Later Heidegger’s Philosophy

The purpose of the paper is to analyze the interrelations between the notions of one’s own and the foreign in later Heidegger’s philosophy. It is pointed out that later Heidegger contextualized the notion of the world by the notion of home and its derivatives “homelessness” and “homecoming” that are of great value in his philosophy. The scrutiny proceeds from the study of the peculiarities of Heidegger’s approach to the problem of being that is considered to be the knot of his philosophy. It is noted that Heidegger, having deserted the traditional ontology already in his early works, continued, nevertheless, using its terms including “being” for a long time and thereby in a way obscured the peculiarities of his approach. Only later Heidegger tried to reject the traditional concept of being as infinitely continuing state in favor of the concept of Ereignis that is usually translated as “appropriating event” or “event of appropriation”. Thus, according to Heidegger, being gives us beings as a whole by appropriating sense to them and thereby turning them into the familiar and accessible environment for dwelling. Just the “givenness” of beings as a whole makes them familiar, one’s own. Accordingly, the “dwelling” means for Heidegger not only the security, but also the intelligibility of the environment, whereas the homelessness means the latter’s uncanny incomprehensibility. It is emphasized that Heidegger’s interpretation of homelessness is closely connected with a standard theoretical model explaining the emergence of the private and public realms. According to this model, just the extension of family as the initial one’s own resulted in the turning of household into city-state that, having been specified by the image of one super-family, added the elements of the foreign to the initial state of society.

Magnomechanical backaction corrections due to coupling to higher-order Walker modes and Kerr nonlinearities

The radiation pressurelike coupling between magnons and phonons in magnets can modify the phonon frequency (magnomechanical spring effect) and decay rate (magnomechanical decay) via dynamical backaction. Such effects have been recently observed by coupling the uniform magnon mode of a magnetic sphere (the Kittel mode) to a microwave cavity. In particular, the ability to evade backaction effects was demonstrated [C. A. Potts et al., Phys. Rev. B 107, L140405 (2023)], a requisite for applications such as magnomechanical-based thermometry. However, deviations were observed from the predicted magnomechanical decay rate within the standard theoretical model. In this work, we account for these deviations by considering corrections due to (i) magnetic Kerr nonlinearities and (ii) the coupling of phonons to additional magnon modes. Provided that such additional modes couple weakly to the driven cavity, our model yields a correction proportional to the average Kittel magnon mode occupation. We focus our results on magnetic spheres, where we show that the magnetostatic Walker modes couple to the relevant mechanical modes as efficiently as the Kittel mode. Our model yields excellent agreement with the experimental data.

Constraints on the hadronic light-by-light in the Melnikov-Vainshtein regime

The muon anomalous magnetic moment continues to attract attention due to the possible tension between the experimentally measured value and the theoretical Standard Model prediction. With the aim to reduce the uncertainty on the hadronic light-by-light contribution to the magnetic moment, we derive short-distance constraints in the Melnikov-Vainshtein regime which are useful for data-driven determinations. In this kinematical region, two of the four electromagnetic currents are close in the four-point function defining the hadronic light-by-light tensor. To obtain the constraints, we develop a systematic operator product expansion of the tensor in question to next-to-leading order in the expansion in operators. We evaluate the leading in αs contributions and derive constraints for the next-to-leading operators that are also valid nonperturbatively.

Characterization of the density-driven counter-flow through a doorway using Large Eddy Simulation

The density-driven bidirectional flow through an open doorway is of prime importance for ventilation and heat distribution between rooms in buildings. Although this flow has been extensively studied in the past, some important flow characteristics, such as unsteady flow phenomena, have not been documented in detail. Therefore, a high-resolution Large Eddy Simulation (LES) of the bulk flow through a doorway is performed. This LES can also serve as a reference solution to compare the accuracy of simpler evaluation methods, from the standard theoretical model calibrated using a discharge coefficient (Cd) to CFD solving the Reynolds-Averaged Navier-Stokes (RANS) equations. Based on LES results, the bidirectional flow can generate turbulent mixing in the middle of the doorway. However, the effects remain limited to the close vicinity of the neutral plane. The bidirectional airstream in the doorway further develops into two non-isothermal jets that entrain a fraction of the airflow. Furthermore, the two jets create large unsteady flow structures when they expand in the adjoining rooms. The results show that unsteady RANS is a good alternative to the resource-intensive LES if the analysis of turbulent jets is not of interest. The standard theoretical model demonstrates that two-dimensional contraction is the dominant effect driving the Cd value, while the viscous effects have a minor influence. Unlike previous studies, LES results show that viscous effects tend to increase the Cd as they moderate the contraction effect. This paper also provides guidelines for the laboratory measurement of Cd and its use in building performance simulation tools.

Electrophoretic Mobility of a Water-in-Oil Droplet Separately Affected by the Net Charge and Surface Charge Density.

Water-in-oil emulsions and droplets exhibit physicochemical properties completely different from those of oil-in-water emulsions and droplets. Thus, directly applying a standard theoretical model to water-in-oil systems cannot describe these anomalous properties. Here, the electrophoretic mobility of a water-in-oil droplet is analytically investigated using Debye-Hückel linearization and neglecting the Marangoni effect. The resulting electrophoretic mobility is shown to be separately dependent on the net charge of the droplet and the surface charge density at the droplet interface. Furthermore, when the net charge is negligible, the electrophoretic mobility is proportional to the surface charge density with a negative coefficient. This indicates that the internal electric double layer inversely contributes to the electrophoresis. This theory is applied to experimental data of water-in-oil emulsions and droplets in the literature, and qualitative and quantitative verification of the theory is discussed.

Is there news in inventories?

We identify total factor productivity (TFP) news shocks using standard VAR methodology and document a new stylized fact: in response to news about future increases in TFP, inventories rise and comove positively with other major macroeconomic aggregates. We show that the standard theoretical model used to capture the effects of news shocks cannot replicate this fact when extended to include inventories. We derive the conditions required to generate a procyclical inventory response by using a wedges approach. To explain the empirical inventory behavior, we consider two mechanisms: sticky wages and the presence of knowledge capital accumulated through learning-by-doing. Only the latter moves the wedges to qualitatively match the empirical behavior. The desire to take advantage of higher future TFP through knowledge capital drives output and hours choices on the arrival of news and leads to inventory accumulation alongside the other macroeconomic variables. The broad-based comovement a model with knowledge capital can generate, supports the view that news shocks are an important driver of aggregate fluctuations.

Jahn-Teller effect analysis at coordination complex [Cu(NH3)4]2+ ion, growth by green synthesis in CuS nanocrystals

We present a preliminary theoretical experimental study to explore the molecular distortion of the copper tetraamin coordination complex [Cu(NH3)4]2+ ion, generated indirectly in aqueous solution at CuS(s) synthesis, previously reported. The coordinate covalent bond theory, is applied to understand the chemical kinetics and thermodynamic stability of the ion governed by the distortion of the molecular configuration. The ligands (NH3) located symmetrically at the vertices of the square and Cu2+ cation situated at center, which stabilizes the electric charge and the free electrons which move on the surface up and down the plane of symmetry of the molecular ion, they are kinetically stabilized by Coulomb barriers. Here, we apply the standard theoretical model for a particle confined in a planar-square potential, considering in principle that it achieves greater relative thermodynamic stability associated with the Jahn-Teller effect. The system reaches the energy level with the minimum relative associated with molecular distortion, which favors crystalline growth, slowly generating CuS(s) nanocrystals. This fact is confirmed with X-ray diffraction (XRD) experimental. The hexagonal crystalline phase with average grain size located at ~3.7–5.7 nm is identified and confirmed by results located at ~4.0–7.0 nm obtained by TEM. By modeling a particle confined in a planar-square potential, degenerate energy levels are quantified. Finally, the kinetic mechanism of crystal growth of CuS(s) nanocrystals can be considered a first-order reaction.

Simplified description of dynamics in neuromorphic resonant tunneling diodes.

In this article, the standard theoretical model accounting for a double barrier quantum well resonant tunneling diode (RTD) connected to a direct current source of voltage is simplified by representing its current-voltage characteristic with an analytically approachable, anti-symmetric N-shaped function. The time and variables involved are also transformed to reduce the number of parameters in the model. Responses observed in previous, more physically accurate studies are reproduced, including slow-fast dynamics, excitability, and bistability, relevant for spiking signal processing. A simple expression for the refractory time of the excitable response is derived and shown to be in good agreement with numerical simulations. In particular, the refractory time is found to be directly proportional to the circuit's intrinsic inductance. The presence or absence of bistability in the dependence of the parameters is also discussed thoroughly. The results of this work can serve as a guideline in prospective endeavors to design and fabricate RTD-based neuromorphic circuits for power and time-efficient execution of neural network algorithms.

The effect of China's domestic public storage on world market prices: the case of cotton

PurposeDuring world price spike periods, the government is more likely to apply trade distortions to stabilize domestic prices, but the trade distortions would amplify fluctuations of international market prices. Which type of policy may stabilize the domestic market price, but not disturb the international market? This paper answers the question by taking public storage policy as a case study in the context of trade policy. Specially, this paper tries to identify the effect of domestic public storage on the world market price.Design/methodology/approachThis article extends a standard theoretical model of trade policy through incorporating domestic public storage policy and makes the model more applicable in the context of China. The extended model is then applied to analysis how domestic public storage policy affects the international market price in the context of trade policy. Finally, a properly identified structural vector auto-regression technique is applied to test the effect of domestic public storage on the world market price by using cotton data from China.FindingsThe theoretical model indicates that China's public storage policy could stabilize the international market price. In order to test the working mechanisms, China's soaring public storage between 2010 and 2014 is employed to identify the effects of China's cotton storage on the volatility of the world price. The empirical findings show that China was able to stabilize the international price of cotton to a non-trivial extent through alteration of its public stockpile.Originality/valueThe first contribution is that this paper extends a standard theoretical model of trade policy to incorporate domestic public storage policy, which enables us to explore the effects of domestic public storage policy on the world price in the context of China. The second major contribution is that this paper provides evidence that, as a large player in the world market, China's public storage policy could stabilize the international agricultural price to a substantial degree.

Probing the screening of the Casimir interaction with optical tweezers

We measure the colloidal interaction between two silica microspheres in aqueous solution in the distance range from $0.2\,\mu$m to $0.5\,\mu$m with the help of optical tweezers. When employing a sample with a low salt concentration, the resulting interaction is dominated by the repulsive double-layer interaction which is fully characterized. The double-layer interaction is suppressed when adding $0.22\,$M of salt to our sample, thus leading to a purely attractive Casimir signal. When analyzing the experimental data for the potential energy and force, we find good agreement with theoretical results based on the scattering approach. At the distance range probed experimentally, the interaction arises mainly from the unscreened transverse magnetic contribution in the zero-frequency limit, with nonzero Matsubara frequencies providing a negligible contribution. In contrast, such unscreened contribution is not included by the standard theoretical model of the Casimir interaction in electrolyte solutions, in which the zero-frequency term is treated separately as an electrostatic fluctuational effect. As a consequence, the resulting attraction is too weak in this standard model, by approximately one order of magnitude, to explain the experimental data. Overall, our experimental results shed light on the nature of the thermal zero-frequency contribution and indicate that the Casimir attraction across polar liquids has a longer range than previously predicted.

ORGANIZATION OF PROTECTION AGAINST ACQUISITIONS AS FORMS OF CORPORATE CONFLICT IN FOREIGN AND RUSSIAN PRACTICE

The article discusses the features of the organization of protection against acquisitions in foreign and Russian practice. The specifics of the manifestation of corporate conflicts, methods of acquisitions are analyzed, conclusions are formulated about the effect of the use of protective mechanisms and the peculiarities of the perception of these processes in Russia and abroad. Different companies apply different degrees of protection, and the question of why this happens remains open. No standard theoretical model has yet determined what explains the observed differences in the degree of protection of companies from acquisitions and how companies choose the degree of protection necessary for them.

Taxing capital and labor when both factors are imperfectly mobile internationally

We revisit the standard theoretical model of tax competition to consider imperfect mobility of both capital and labor. We show that the mobility of one factor affects the taxation of both factors and that the ”race-to-the-bottom” narrative (with burden shifting) applies essentially to capital-exporting countries. We validate our predictions using a panel of 29 OECD countries over the period of 1997–2017. The quantitative contribution of rising capital mobility to the decline of corporate income tax rates over our sample period is nonetheless less than that of population ageing.

Understanding the effect of the MFI framework on the mechanism and kinetics of direct CH3COOH formation from the Co-activation of CO2 and CH4

Nowadays, theoretical calculations are playing a pivotal role in understanding the underlying reaction mechanism and at the same time used for exploration of the zeolite-based catalysts. For such systems, an inconsistency is seen in formulating the active site and choosing the size of the zeolite framework. Herein, we have formulated the standard theoretical model for the MFI-based catalytic systems considering the most recent experimental findings.[1] The formulated model is used for the explanation of the mechanism of acetic acid formation by the co-activation of CO2 and CH4 over the MFI based catalyst, which excellently justifies the experimental results. The following conclusions are drawn from the work, a sufficiently large zeolite framework is critical to validate the experimental findings. The extended zeolite framework is crucial for accurate optimization of the active site, drawing the plausible mechanisms and predicting the correct rate-limiting step of the reaction. Moreover, the neighbor Al-Al atoms must be kept away from each other by at-least two Si-centers to be consistent with the experiment.

Millstone Hill ISR Measurements of Small Aspect Angle Spectra

AbstractThe Millstone Hill incoherent scatter (IS) radar is used to measure spectra close to perpendicular to the Earth's magnetic field, and the data are fit to three different forward models to estimate ionospheric temperatures. IS spectra measured close to perpendicular to the magnetic field are heavily influenced by Coulomb collisions, and the temperature estimates are sensitive to the collision operator used in the forward model. The standard theoretical model for IS radar spectra treats Coulomb collisions as a velocity independent Brownian motion process. This gives estimates of Te/Ti < 1 when fitting the measured spectra for aspect angles up to 3.6°, which is a physically unrealistic result. The numerical forward model from Milla and Kudeki (2011, https://doi.org/10.1109/TGRS.2010.2057253) incorporates single‐particle simulations of velocity‐dependent Coulomb collisions into a linear framework, and when applied to the Millstone data, it predicts the same Te/Ti ratios as the Brownian theory. The new approach is a nonlinear particle‐in‐cell (PIC) code that includes velocity‐dependent Coulomb collisions which produce significantly more collisional and nonlinear Landau damping of the measured ion‐acoustic wave than the other forward models. When applied to the radar data, the increased damping in the PIC simulations will result in more physically realistic estimates of Te/Ti. This new approach has the greatest impact for the largest measured ionospheric densities and the lowest radar frequencies. The new approach should enable IS radars to obtain accurate measurements of plasma temperatures at times and locations where they currently cannot.

Is There News in Inventories?

This paper identifies total factor productivity (TFP) news shocks using standard VAR methodology and documents a new stylized fact: in response to news about future increases in TFP, inventories rise and comove positively with other major macroeconomic aggregates. The authors show that the standard theoretical model used to capture the effects of news shocks cannot replicate this fact when extended to include inventories. To explain the empirical inventory behavior, they develop a framework that relies on the presence of knowledge capital accumulated through a learning-by-doing process. The desire to take advantage of higher future TFP through knowledge capital drives output and hours choices on the arrival of news and leads to inventory accumulation alongside other macroeconomic variables. The broad-based comovement the authors document supports the view that news shocks are an important driver of aggregate fluctuations.

Household Purchasing Productivity: Concept and Consequences

To provide a logically coherent explanation for the high correlations found between a nation’s economic affluence and overall subjective wellbeing, this research takes a micro-macro systems approach. We extend the standard micro theoretical model of the household, by separating purchasing from home production. This separation allows analysis of the opportunity costs in trading-off time and money (as in make or buy decisions) for various household processes. By expanding the household model, a formula is derived to empirically test the relationship between aggregate household income and aggregate household purchasing productivity. The data, although rudimentary, support the hypothesis that growing economic affluence results in greater purchasing productivity. That is, aggregate household demand for marketing output increases more than proportionally to the purchasing time inputs to acquire it; and this increase in household purchasing productivity affords the option of trading off money for time (less make, more buy). Increasing purchasing productivity provides greater opportunities for household satisfaction, ceteris paribus, by freeing up time in household production; thereby providing more time and/or greater quality sensory data input into the consumption process to create satisfaction. Conversely, falling economic affluence has the reverse effect. It results in declining purchasing productivity and the necessity of trading off time for money (more make, less buy). Consequently, reduced opportunity for household satisfaction because of less time and/or lesser quality sensory characteristics input into the consuming process. Thus household purchasing productivity, which explicates the trade-off between make (or time) in home production versus buy (or money) in household purchasing, we argue, provides the linkage to explain a nation’s standard of living and potential happiness.

Application of portable streamer traps for obtaining point measurements of total longshore sediment transport rates in mixed sand and gravel beaches

Observations of the depth integrated and time averaged sediment transport on a mixed sand and gravel (MSG) beach are presented and analysed to examine the performance of a new portable streamer trap. Measurement of the longshore sediment transport rate in the surf zone remains one of the great challenges in coastal engineering and coastal sciences. Sediment traps for sand beaches have proven useful in the past, but are not suitable for MSG beaches. This paper describes a portable depth-integrated streamer trap designed to measure the depth-integrated combined bed load and suspended longshore sediment transport on MSG beaches. The device consists of a polyester sieve cloth mounted into a rectangular holding frame. The stability of the device is achieved by gravity: the combined weight of the device and the operator, who is standing on and down-current of the device. The device has been tested in the field under moderate wave conditions at Minsmere, UK. We show that the observed suspended and bed load sediment transport are proportional to the wave energy flux, as formulated in the standard theoretical model, CSHORE. The data suggest that the empirical efficiency of wave breaking and bed load parameter are several orders of magnitude larger than that previously observed for uniform fine sand values.

Methods in Experimental Work Break Research: A Scoping Review.

The number of studies on work breaks and the importance of this subject is growing rapidly, with research showing that work breaks increase employees’ wellbeing and performance and workplace safety. However, comparing the results of work break research is difficult since the study designs and methods are heterogeneous and there is no standard theoretical model for work breaks. Based on a systematic literature search, this scoping review included a total of 93 studies on experimental work break research conducted over the last 30 years. This scoping review provides a first structured evaluation regarding the underlying theoretical framework, the variables investigated, and the measurement methods applied. Studies using a combination of measurement methods from the categories “self-report measures,” “performance measures,” and “physiological measures” are most common and to be preferred in work break research. This overview supplies important information for ergonomics researchers allowing them to design work break studies with a more structured and stronger theory-based approach. A standard theoretical model for work breaks is needed in order to further increase the comparability of studies in the field of experimental work break research in the future.

Language Acquisition, Employment Status, and the Earnings of Jewish and Non‐Jewish Immigrants in Israel

AbstractThis article analyses the Hebrew language proficiency, probability of employment, and labour market earnings of immigrants in Israel. It uses the 2010/11 Immigrant Absorption Survey conducted by the Israeli CBS. In addition to standard immigration, demographic, and human capital variables, the analysis includes unique features: the study of long‐duration immigrants, analyses of males’ and females’ primary reasons for immigration, the subsidized intensive Hebrew language training programme, Ethiopian Jews, and Jewish and non‐Jewish immigrants from the Former Soviet Union. Results from multivariate analyses largely accord with the “standard theoretical model” of language proficiency regarding the mechanisms of “exposure”, “efficiency”, and “economic incentives”. Acquaintance with the local language increases the likelihood of being employed and has positive earnings outcomes. We discuss implications of the findings for public policy which can improve the adjustment of these new immigrants to their new society, hence also moderate inter‐group tensions.