Short-distance Interactions Research Articles

Role of the short-distance interaction in e+e−→γX(3872)

In this study, we analyze the cross-section data from the e+e−→γJ/ψω process to explore both short-distance and long-distance interactions for the radiative transition Y(4200)→γX(3872). We investigate the short-distance effects through the E1 transition among the cc¯ components, and the long-distance effects via hadronic loop diagrams. Our numerical analysis reveals that short-distance interactions play a significantly larger role in the radiative transition than that of the long-distance interactions. This finding underscores the importance of the compact cc¯ components in both the initial and the final states for accurately understanding the cross-section σ[e+e−→γJ/ψω]. Furthermore, with the help of relative branch ratio R we estimate the Γ[Y(4200)→γX(3872)] implied in the experimental study. Finally, we also discuss the possible existence of the ψ(4040) signal within the cross-section data. Published by the American Physical Society 2024

On the symmetrical and unsymmetrical reference state for ionic liquids modeling: Electrolytes versus neutral compounds

The symmetrical and unsymmetrical conventions for the reference state of the activity coefficients was applied to the Pitzer-Debye-Hückel (PDH) equation to describe long-distance interactions coupled with the UNIversal QUAsi-Chemical (UNIQUAC) model to describe short-distance interactions in binary temperature-composition (T, x) data. Based on the results of a previous work related to the closest approach parameter (ρ), in the PDH equation, a novel methodology was refined in order to obtain a more accurate description of the behavior of ionic liquids (ILs) in water. The aim of this work is to step further in a modern methodology that considers ILs as charged compounds, i.e., species that dissociate, while accounting for this dissociation extent. This study intends to set the groundwork for powerful and valuable tools for the scientific community in the field of chemistry, geology, material science, medicine, biochemistry, as well as in many engineering areas, such as chemical, biochemical, electrical and petroleum engineering.

Second Landau level projection of antiholomorphic Pfaffian wave functions

We propose a new state described by the second Landau level (SLL) projection of a generalized Moore-Read Pfaffian wavefunction with an antiholomorphic pairing component. Unlike the PH-Pfaffian state which is described by the lowest Landau level (LLL) projection of the same antiholomorphic Pfaffian wavefunction, we find the proposed state, which we call the SLL PH-Pfaffian, represents a gapped, incompressible phase, and provides an excellent description for the exact ground state of finite-size SLL Coulomb-interacting electrons over a range of the short distance interaction strength. We also find the SLL PH-Pfaffian, when mapped to the LLL, has a very large overlap and the same low-energy orbital entanglement spectrum structures with the anti-Pfaffian state. We discuss possible interpretations of our results on the nature of the topological order of both states.

Hydrodynamic interaction of a squat submarine towed by a marine vessel: Experimental investigation

This research investigates the short-distance hydrodynamic interaction of a squat submarine towed by a marine vessel. A one-tenth scaled captive model of a 0.625-m squat submarine is constructed along with a 1.5-m Fridsma ship to perform 69 unique experiments in a 4 × 6 × 400-m3 water tank located in a towing tank center. The submarine model is a new mini-submersible, Apam-Napat SMSD type, with an L/D ratio below four. The cable is specified, regarding its weight per unit length, using a scaling method introduced in this paper. The submarine-cable-ship system is tested for nine various relative lengths and depths at short-distance conditions. In each case, drag and heave forces are recorded and presented for the vessels using resistance tests at velocities of 0.5, 1.0, and 1.5-m/s. Finally, outputs are extended to develop 2-dimensional contours to estimate the interactional forces in the full domain. The results show a critical zone behind the ship around a depth of 0.75D where ship drag forces are increased by up to 177% compared to free-running conditions. In addition, comparing the towing mechanism to self-propelling operations shows that the towing effect dominates vessel interaction, increasing the drag forces by up to 240% when the ship tows the submarine.

Molecular Nature of X(3872) in B 0 → K 0 X(3872) and B + K + X(3872) Decays

We investigate the decays of B 0 → K 0 X(3872) and B + → K + X(3872) based on the picture where the X(3872) resonance is strongly coupled to the channel. In addition to the decay mechanism where the X(3872) resonance is formed from the pair hadronization with the short-distance interaction, we have also considered the rescattering diagrams in the long-distance scale, where D and are formed from c and separately. Because of the difference of the mass thresholds of charged and neutral channels, and the rather narrow width of the X(3872) resonance, at the X(3872) mass, the loop functions of and are much different. Taking this difference into account, the ratio of can be naturally obtained. Based on this result, we also evaluate the decay widths of . It is expected that future experimental measurements of these decays can be used to elucidate the nature of the X(3872) resonance.

Regularization in nonperturbative extensions of effective field theory

The process of renormalization in nonperturbative Hamiltonian effective field theory (HEFT) is examined in the $\mathrm{\ensuremath{\Delta}}$-resonance scattering channel. As an extension of effective field theory incorporating the L\"uscher formalism, HEFT provides a bridge between the infinite-volume scattering data of experiment and the finite-volume spectrum of energy eigenstates in lattice QCD. HEFT also provides phenomenological insight into the basis-state composition of the finite-volume eigenstates via the state eigenvectors. The Hamiltonian matrix is made finite through the introduction of finite-range regularization. The extent to which the established features of this regularization scheme survive in HEFT is examined. In a single-channel $\ensuremath{\pi}N$ analysis, fits to experimental phase shifts withstand large variations in the regularization parameter $\mathrm{\ensuremath{\Lambda}}$, providing an opportunity to explore the sensitivity of the finite-volume spectrum and state composition on the regulator. While the L\"uscher formalism ensures the eigenvalues are insensitive to $\mathrm{\ensuremath{\Lambda}}$ variation in the single-channel case, the eigenstate composition varies with $\mathrm{\ensuremath{\Lambda}}$; the admission of short-distance interactions diminishes single-particle contributions to the states. In the two-channel $\ensuremath{\pi}N$, $\ensuremath{\pi}\mathrm{\ensuremath{\Delta}}$ analysis, $\mathrm{\ensuremath{\Lambda}}$ is restricted to a small range by the experimental data. Here the inelasticity is particularly sensitive to variations in $\mathrm{\ensuremath{\Lambda}}$ and its associated parameter set. This sensitivity is also manifest in the finite-volume spectrum for states near the opening of the $\ensuremath{\pi}\mathrm{\ensuremath{\Delta}}$ scattering channel. Future high-quality lattice QCD results will be able to discriminate $\mathrm{\ensuremath{\Lambda}}$, describe the inelasticity, and constrain a description of the basis-state composition of the energy eigenstates. Finally, HEFT has the unique ability to describe the quark-mass dependence of the finite-volume eigenstates. The robust nature of this capability is presented and used to confront current state-of-the-art lattice QCD calculations.

Significant Effect of the Flexibility of Bridging Alkyl Chains on the Proximity of Stacked Porphyrin and Phthalocyanine Conjugated with a Fourfold Rotaxane Linkage.

Spatial distance is an important factor in controlling the functional interactions between molecular units in a conjugate; therefore, the bridging unit has been closely examined. Here, we examined the effect of the flexibility of bridging alkyl chains on the proximity of stacked porphyrin and phthalocyanine conjugated with a fourfold rotaxane linkage. We found that closely stacking two π systems requires bridging alkyl chains above a certain length, and the shorter bridges hinder stacking because of their lower flexibility. The stacking distance between porphyrin and phthalocyanine in the conjugate with decyl (C10 ) chains was estimated to be 4.03 Å and showed a unique physical character arising from short-distance interactions. The longer alkyl chains minimized steric restriction inside the fourfold rotaxane and allowed efficient communication between the porphyrin and phthalocyanine units. This is due to the flexibility of the side chains.

Strange Metals from Melting Correlated Insulators in Twisted Bilayer Graphene.

Even as the understanding of the mechanism behind correlated insulating states in magic-angle twisted bilayer graphene converges toward various kinds of spontaneous symmetry breaking, the metallic "normal state" above the insulating transition temperature remains mysterious, with its excessively high entropy and linear-in-temperature resistivity. In this Letter, we focus on the effects of fluctuations of the order parameters describing correlated insulating states at integer fillings of the low-energy flat bands on charge transport. Motivated by the observation of heterogeneity in the order-parameter landscape at zero magnetic field in certain samples, we conjecture the existence of frustrating extended-range interactions in an effective Ising model of the order parameters on a triangular lattice. The competition between short-distance ferromagnetic interactions and frustrating extended-range antiferromagnetic interactions leads to an emergent length scale that forms stripy mesoscale domains above the ordering transition. The gapless fluctuations of these heterogeneous configurations are found to be responsible for the linear-in-temperature resistivity as well as the enhanced low-temperature entropy. Our insights link experimentally observed linear-in-temperature resistivity and enhanced entropy to the strength of frustration or, equivalently, to the emergence of mesoscopic length scales characterizing order-parameter domains.

Wang-MacDonald d -Wave Vortex Cores Observed in Heavily Overdoped Bi2Sr2CaCu2O8+δ

Low-magnetic-field scanning tunneling spectroscopy of individual Abrikosov vortices in heavily overdoped Bi2Sr2CaCu2O8+δ unveils a clear d-wave electronic structure of the vortex core, with a zero-bias conductance peak at the vortex center that splits with increasing distance from the core. We show that previously reported unconventional electronic structures, including the low-energy checkerboard charge order in the vortex halo and the absence of a zero-bias conductance peak at the vortex center, are direct consequences of short intervortex distance and consequent vortex-vortex interactions prevailing in earlier experiments.Received 16 February 2021Revised 29 April 2021Accepted 17 June 2021DOI:https://doi.org/10.1103/PhysRevX.11.031040Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasLocal density of statesVortices in superconductorsd-wavePhysical SystemsHigh-temperature superconductorsTechniquesScanning tunneling microscopyScanning tunneling spectroscopyCondensed Matter, Materials & Applied Physics

One-step to synthesize multilevel structured ZnO films with exceptional wettability

A facile one-step synthesis approach was developed to prepare ZnO films with multilevel structures composed of microclusters and nanohairs. The hierarchically structured ZnO films demonstrate peculiar wettability—superhydrophobicity but with high normal adhesion. The very high aspect-ratio of ZnO nanohairs minimizes the area of the (002) high potential surface which is the preferential growth direction. Microclusters of ZnO ensure the sufficient short-distance interactions for the normal adhesion, while the overall ZnO platforms with unique geometrical configuration and chemical composition provide the bulk scale conformity necessary for superhydrophobicity and high adhesion for rough or contoured surfaces. The superhydrophobicity of the ZnO nanohair films can be explained with the Cassie impregnating model or partial wetting model. Thanks to its purity as an inorganic material, the superhydrophobic ZnO films exhibit outstanding durability.

Segregation of interstitial light elements at grain boundaries in molybdenum

We investigated the segregation of H, O, N and C at the grain boundaries in molybdenum using ab initio calculations. These light elements have the short-distance interactions with GBs and show the preferential to segregate around GBs. The most energetically favorable trapping sites were found to locate right at the open space of boundaries. Such segregation is associated with the low electron density at the GBs, where the segregation energy is the lowest. Our studies would help understand the possible strengthening or weakening caused by impurities in molybdenum.

Effective field theory approach to lepton number violating decays K\xb1\u2192 \u03c0\u2213l\xb1l\xb1: short-distance contribution

This is the first paper of our systematic efforts on lepton number violating (LNV) hadronic decays in the effective field theory approach. These decays provide information complementary to popular nuclear neutrinoless double-β (0νββ) decay in that they can probe LNV interactions involving heavier quarks and charged leptons. We may call them hadronic 0νββ decays in short, though β refers to all charged leptons. In this work we investigate the decays K±→ π∓l±l± that arise from short-distance or contact interactions involving four quark fields and two charged lepton fields, which have canonical dimension nine (dim-9) at leading order in low energy effective field theory (LEFT). We make a complete analysis on the basis of all dim-9 operators that violate lepton number by two units, and compute their one-loop QCD renormalization effects. We match these effective interactions in LEFT to those in chiral perturbation theory (χPT) for pseudoscalar mesons, and determine the resulting hadronic low energy constants (LECs) by chiral symmetry and lattice results in the literature. The obtained decay rate is general in that all physics at and above the electroweak scale is completely parameterized by the relevant Wilson coefficients in LEFT and hadronic LECs in χPT. Assuming the standard model effective field theory (SMEFT) is the appropriate effective field theory between some new physics scale and the electroweak scale, we match our LEFT results to SMEFT whose leading effective interactions arise from LNV dim-7 operators. This connection to SMEFT simplifies significantly the interaction structures entering in the kaon decays, and we employ the current experimental bounds to set constraints on the relevant Wilson coefficients in SMEFT.

Key physicochemical characteristics governing organic micropollutant adsorption and transport in ion-exchange membranes during reverse electrodialysis

The co-generation of electricity and electrodialysis of seawater in a hybrid system is a promising approach to overcome water scarcity. Reverse electrodialysis harvests energy from the salinity gradient, where seawater is used as a high salinity stream while secondary treated wastewater can be used as a sustainable low salinity stream. Treated wastewater contains organic micropollutants, which can be transported to the seawater stream. The current research establishes a connection between adsorption and transport of organic micropollutants in ion exchange membranes, using a cross-flow stack in adsorption and zero-current experiments. To mimic the composition of treated wastewater, a mixture of nineteen organic micropollutants of varied physicochemical characteristics (e.g. size, charge, polarity, hydrogen donor/acceptor count, hydrophobicity) at environmentally relevant concentrations was used. Depending on the charge, micropollutants develop different types of mechanisms responsible for short-distance interactions with ion-exchange membranes, which has a direct influence in their transport behavior. This study provides a rational basis for the optimization/design of next-generation ion-exchange membranes, in which the permeability toward organic micropollutants should be also included. This investigation highly contributes to understanding the potential hazard posed by organic micropollutants in reverse electrodialysis in seawater desalination systems, where treated wastewater is used as a low salinity stream.

Calculations of the Sommerfeld effect in a unified wave function framework

In this paper, we suggest a method of a complete calculation of the Sommerfeld effect in both the s-wave and p-wave annihilation situations. The basic idea is to uniformly consider the equal-time Beth-Salpeter wave functions of both the dark matter and the final state particles, then short-distance interactions can be parametrized as a cross-term considering the equations. Solving these equations will result in the complete formulas of the cross sections with the Sommerfeld effects.

Building models for B-physics anomalies

Several different experiments show evidences of Lepton Flavour Universality violation in semi-leptonic B meson decays, both in charged and neutral currents. These anomalies can be interpreted in terms of new short-distance interactions that involve mainly the third generation of fermions. I will first discuss the present status of the anomalies, and their connection to other low- and high-energy observables, in a model-independent way, adopting an Effective Field Theory approach based on a CKM-like flavour structure. I will then extend the analysis to a few simple UV completions with different types of mediator, discussing the main issues that have to be faced in each case. A few models emerge, which look capable of accommodating both charged- and neutral-current anomalies consistently with all the experimental bounds, with associated flavour and high-pT signatures within the reach of present and future experiments.

Local connectivity of the resting brain connectome in patients with low back-related leg pain: A multiscale frequency-related Kendall's coefficient of concordance and coherence-regional homogeneity study.

Increasing evidence has suggested that central plasticity plays a crucial role in the development and maintenance of (chronic) nonspecific low back pain. However, it is unclear how local or short-distance functional interactions contribute to persisting low back-related leg pain (LBLP) due to a specific condition (i.e., lumbar disc herniation). In particular, the multiscale nature of local connectivity properties in various brain regions is still unclear. Here, we used voxelwise Kendall's coefficient of concordance (KCC) and coherence (Cohe) regional homogeneity (ReHo) in the typical (0.01–0.1 Hz) and five specific frequency (slow-6 to slow-2) bands to analyze individual whole-brain resting-state functional magnetic resonance imaging scans in 25 persistent LBLP patients (duration: 36.7 ± 9.6 months) and 26 healthy control subjects. Between-group differences demonstrated significant alterations in the KCC- and Cohe- ReHo of the right cerebellum posterior lobe, brainstem, left medial prefrontal cortex and bilateral precuneus in LBLP patients in the typical and five specific frequency bands, respectively, along with interactions between disease status and the five specific frequency bands in several regions of the pain matrix and the default-mode network (P < .01, Gaussian random field theory correction). The altered ReHo in the five specific frequency bands was correlated with the duration of pain and two-point discrimination, which were assessed using partial correlational analysis. These results linked the course of disease to the local connectivity properties in specific frequency bands in persisting LBLP. In future studies exploring local connectome association in pain conditions, integrated frequency bands and analytical methods should be considered.

A Bio-inspired Motivational Decision Making System for Social Robots Based on the Perception of the User.

Nowadays, many robotic applications require robots making their own decisions and adapting to different conditions and users. This work presents a biologically inspired decision making system, based on drives, motivations, wellbeing, and self-learning, that governs the behavior of the robot considering both internal and external circumstances. In this paper we state the biological foundations that drove the design of the system, as well as how it has been implemented in a real robot. Following a homeostatic approach, the ultimate goal of the robot is to keep its wellbeing as high as possible. In order to achieve this goal, our decision making system uses learning mechanisms to assess the best action to execute at any moment. Considering that the proposed system has been implemented in a real social robot, human-robot interaction is of paramount importance and the learned behaviors of the robot are oriented to foster the interactions with the user. The operation of the system is shown in a scenario where the robot Mini plays games with a user. In this context, we have included a robust user detection mechanism tailored for short distance interactions. After the learning phase, the robot has learned how to lead the user to interact with it in a natural way.

Local functional connectivity alterations in schizophrenia, bipolar disorder, and major depressive disorder

BackgroundLocal functional connectivity (FC) indicates local or short-distance functional interactions and may serve as a neuroimaging marker to investigate the human brain connectome. Local FC alterations suggest a disrupted balance in the local functionality of the whole brain network and are increasingly implicated in schizophrenia (SZ), bipolar disorder (BD), and major depressive disorder (MDD). MethodsWe aim to examine the similarities and differences in the local FC across SZ, BD, and MDD. In total, 537 participants (SZ, 126; BD, 97; MDD, 126; and healthy controls, 188) completed resting-state functional magnetic resonance imaging at a single site. The local FC at resting state was calculated and compared across SZ, BD, and MDD. ResultsThe local FC increased across SZ, BD, and MDD within the bilateral orbital frontal cortex (OFC) and additional region in the left OFC extending to putamen and decreased in the primary visual, auditory, and motor cortices, right supplemental motor area, and bilateral thalami. There was a gradient in the extent of alterations such that SZ > BD > MDD. LimitationsThis cross-sectional study cannot consider medications and other clinical variables. ConclusionsThese findings indicate a disrupted balance between network integration and segregation in SZ, BD, and MDD, including over-integration via increased local FC in the OFC and diminished segregation of neural processing with the weakening of the local FC in the primary sensory cortices and thalamus. The shared local FC abnormalities across SZ, BD, and MDD may shed new light on the potential biological mechanisms underlying these disorders.

Three-dimensional hierarchical aggregation growth of perovskite ferroelectric microplates with a high-efficient methylene blue adsorption performance

Square-shape and single-crystal-like perovskite PbTiO3 (PT) microplates have been prepared via a facile one-step hydrothermal route by employing ethanol as surfactant. The as-synthesized PT microplates were characterized to exhibit a side length of 4–6µm and a height of ~ 150–200nm. It is interesting to find that the PT microplates were formed via a complex three-dimensional aggregation and oriented attachment process, where small sized precursor-transformed-PT nanoplates were determined to be the building blocks. Such process was proposed to arise from a long-distance electric dipole interaction and short-distance molecular interaction, giving rise to the square-shape and single-crystal-like microplates with large-scale polar {001} exposed. Moreover, these microplates demonstrate a remarkable adsorption performance of methylene blue (MB) from aqueous solution, despite of a low specific area (~ 3.48m2/g). It was revealed that the high-efficient adsorption could be attributed to an electrostatic interaction between MB and polar {001} of the microplates, offering a promising approach to selectively treating pollutant solution with organic molecules.

Point-particle effective field theory III: relativistic fermions and the Dirac equation

We formulate point-particle effective field theory (PPEFT) for relativistic spin-half fermions interacting with a massive, charged finite-sized source using a first-quantized effective field theory for the heavy compact object and a second-quantized language for the lighter fermion with which it interacts. This description shows how to determine the near-source boundary condition for the Dirac field in terms of the relevant physical properties of the source, and reduces to the standard choices in the limit of a point source. Using a first-quantized effective description is appropriate when the compact object is sufficiently heavy, and is simpler than (though equivalent to) the effective theory that treats the compact source in a second-quantized way. As an application we use the PPEFT to parameterize the leading energy shift for the bound energy levels due to finite-sized source effects in a model-independent way, allowing these effects to be fit in precision measurements. Besides capturing finite-source-size effects, the PPEFT treatment also efficiently captures how other short-distance source interactions can shift bound-state energy levels, such as due to vacuum polarization (through the Uehling potential) or strong interactions for Coulomb bound states of hadrons, or any hypothetical new short-range forces sourced by nuclei.