Form Factor Research Articles

Self-consistent analysis for the ηc→γγ process

The next-to-next-to-leading-order (NNLO) perturbative QCD (pQCD) predictions for both the decay width and the transition form factor in the ηc→γγ process, based on nonrelativistic QCD (NRQCD), deviate from precise experimental measurements. These significant discrepancies have cast doubt on the applicability of NRQCD to charmonium processes. In this paper, we analyze the ηc→γγ process by applying the principle of maximum conformality (PMC), a systematic method for eliminating renormalization scheme-and-scale ambiguities. The PMC renormalization scales are determined by absorbing the nonconformal β-terms that govern the behavior of the QCD running coupling via the renormalization group equation. We obtain the PMC scale Q⋆=4.49mc for the ηc→γγ decay width. Even after using the PMC method, the convergence of the pQCD series is still poor, which indicates the importance of uncalculated next-to-next-to-next-to-leading-order and higher-order terms. The resulting value for Γηc→γγ is in agreement with the Particle Data Group’s reported value of Γηc→γγ=5.1±0.4 keV within the bounds of uncertainties. Moreover, the transition form factor obtained using the PMC is also in good agreement with precise experimental measurements. The application of the PMC suggests a potential resolution to ηc→γγ puzzle and supports the applicability of NRQCD to charmonium processes. Published by the American Physical Society 2025

Spectral anomalies and broken symmetries in maximally chaotic quantum maps

Spectral statistics such as the level spacing statistics and spectral form factor (SFF) are widely expected to accurately identify “ergodicity,” including the presence of underlying macroscopic symmetries, in generic quantum systems ranging from quantized chaotic maps to interacting many-body systems. By studying various quantizations of maximally chaotic maps that break a discrete classical symmetry upon quantization, we demonstrate that this approach can be misleading and fail to detect macroscopic symmetries. Notably, the same classical map can exhibit signatures of different random matrix symmetry classes in short-range spectral statistics depending on the quantization. While the long-range spectral statistics encoded in the early time ramp of the SFF are more robust and correctly identify macroscopic symmetries in several common quantizations, we also demonstrate analytically and numerically that the presence of Berry-like phases in the quantization leads to spectral anomalies, which break this correspondence. Finally, we provide numerical evidence that long-range spectral rigidity remains directly correlated with ergodicity in the quantum dynamical sense of visiting a complete orthonormal basis.

A Vertically‐Stacked Optoelectronic Sensor for Localized Hemodynamics Monitoring

AbstractOptoelectronic sensors are widely used as they monitor important biosignals in real‐time, many times in non‐invasive ways by making use of the degree of light absorption through live tissues. In many of the applications, the optoelectronic sensors in a small form factor with attachable or insertable forms enable understanding the critically important biological states and mechanisms, including localized activities in very complex biological environments, such as in the brain. In this report, an optoelectronic sensor is presented, built by vertically integrating two different micro light emitting diodes (microLEDs) next to a photodetector with a predetermined interoptode distance in attachable or insertable forms. Both of the optical simulations and experimental results validate the designs and capabilities of the approach, by demonstrating the sensors on a human finger, around femoral vessels in a mouse model, and in mouse brains to monitor optogenetically‐induced localized hemodynamics.

Technical roadmap of ultra-thin crystalline silicon-based bioelectronics

Abstract Ultra-thin Crystalline silicon stands as a cornerstone material in the foundation of modern micro and nano electronics. Despite the proliferation of various materials including oxide-based, polymer-based, carbon-based, and 2D materials, crystal silicon continues to maintain its stronghold, owing to its superior functionality, scalability, stability, reliability, and uniformity. Nonetheless, the inherent rigidity of the bulk silicon leads to incompatibility with soft tissues, hindering the utilization amid biomedical applications. Because of such issues, decades of research have enabled successful utilization of various techniques to precisely control the thickness and morphology of silicon layers at the scale of several nanometres. This review provides a comprehensive exploration on the features of ultra-thin single crystalline silicon as a semiconducting material, and its role especially among the frontier of advanced bioelectronics. Key processes that enable the transition of rigid silicon to flexible form factors are exhibited, in accordance with their chronological sequence. The inspected stages span both prior and subsequent to transferring the silicon membrane, categorized respectively as on-wafer manufacturing and rigid-to-soft integration. Extensive guidelines to unlock the full potential of flexible electronics, are provided through ordered analysis of each manufacturing procedure, the latest findings of biomedical applications, along with practical perspectives for researchers and manufacturers.

Modeling small-angle X-ray scattering in quiescently crystallized polymers in the absence of long-period dispersity

To explain the single and wide first-order long-period peak observed in semicrystalline polymers, classical small-angle X-ray scattering (SAXS) theory regards the dispersity in lamellar thickness/long period as the key structural feature of semicrystalline polymers. Other factors affecting the SAXS pattern such as the lateral size of a lamellar stack, the number of lamellar crystals in a stack and linear crystallinity have been overlooked as secondary factors, preventing structure extraction from SAXS. In this study, we attempted to establish a scattering equation for semicrystalline polymers formed during quiescent crystallization without considering dispersity in the long period/lamellar thickness. The results indicate that the lateral size is the key factor leading to the unique SAXS pattern in semicrystalline polymers and the absence of the linear region in the correlation function. SAXS in semicrystalline polymers results from minor lamellar stacks with small intersection angles with the incident X-rays. On the basis of the results, we suggest employing a revised interface distribution function to obtain structural information after recovering higher-order weak long-period peaks by a difference method. Half of the q 4 correction is to eliminate the influence of the form factor, while the other half is to remove the factor of 1/q 2 in the structure factor. This study helps to further our understanding of SAXS in semicrystalline polymers.

Probing $D_s^*$-meson longitudinal twist-2 LCDA

Abstract In this paper, we carry on an investigation of the semileptonic decays $B_s\to D_s^*\ell \bar\nu_{\ell}$. Firstly, we derive the moments of the $D_s^*$-meson longitudinal leading-twist light-cone distribution amplitude (LCDA) based on QCD sum rules within background field theory framework. Considering the contributions of the vacuum condensates up to dimension-six, its first ten non-zero $\xi$-moments at the initial scale $\mu_0 =1.3~{\rm GeV}$ are $\langle \xi^{\|, 1}_{2; D_s^*} \rangle|_{\mu_0} = -0.302_{-0.046}^{+0.038}$, $\langle\xi^{\|, 2}_{2;D_s^*}\rangle|_{\mu_0} = +0.229_{-0.034}^{+0.039}$, $\langle\xi^{\|, 3}_{2;D_s^*}\rangle|_{\mu_0} = -0.121_{-0.019}^{+0.015}$, $\langle\xi^{\|, 4}_{2;D_s^*}\rangle|_{\mu_0} = +0.101_{-0.014}^{+0.017}$, $\langle\xi^{\|, 5}_{2; D_s^*} \rangle|_{\mu_0} = -0.066_{-0.010}^{+0.009}$, $\langle\xi^{\|, 6}_{2;D_s^*}\rangle|_{\mu_0} = +0.053_{-0.007}^{+0.009}$, $\langle\xi^{\|, 7}_{2;D_s^*}\rangle|_{\mu_0} = -0.041_{-0.007}^{+0.006}$, $\langle\xi^{\|, 8}_{2;D_s^*}\rangle|_{\mu_0} = +0.037_{-0.005}^{+0.006}$, $\langle\xi^{\|, 9}_{2; D_s^*} \rangle|_{\mu_0} = -0.026_{-0.004}^{+0.003}$ and $\langle\xi^{\|, 10}_{2;D_s^*}\rangle|_{\mu_0} = +0.025_{-0.004}^{+0.004}$, respectively. Meanwhile, we construct the $D_s^*$-meson longitudinal leading-twist LCDA by using the light-cone harmonic oscillator model. Then, using those moments, we fix the model parameters $\alpha_{2;D_s^*}$ and $B_1^{2;D_s^*}$ by the least square method and apply them to calculate $B_s \to D_s^*$ transition form factors $A_1(q^2), A_2(q^2)$ and $V(q^2)$ that are derived by using the QCD light-cone sum rules. At the large recoil region, we obtain $A_1(0) =0.632_{-0.135}^{+0.228}, A_2(0) =0.706_{-0.092}^{+0.109}$ and $V(0) =0.647_{-0.069}^{+0.076}$. Those form factors are then extrapolated to the allowed whole physical $q^2$-region through the simplified series expansion. Finally, we obtain the branching fractions for the two decay channels $B_s\to D_s^*\ell\bar\nu_\ell$, $\it i.e.$ ${\cal B}(B_s^0 \to D_s^{*+}e^-\bar\nu_e)=(5.45_{-1.57}^{+2.15})\times 10^{-2}$, ${\cal B}(B_s^0 \to D_s^{*+}\mu^-\bar\nu_\mu)=(5.43_{-1.57}^{+2.14})\times 10^{-2}$. In addition, we present the CKM matrix element $|V_{cb}|$ by matching the LHCb Collaboration branching fraction, yielding a value of $|V_{cb}| = (40.11_{-7.49}^{+6.54})\times 10^{-3}$. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Article funded by SCOAP3 and published under licence by Chinese Physical Society and the Institute of High Energy Physics of the Chinese Academy of Science and the Institute of Modern Physics of the Chinese Academy of Sciences and IOP Publishing Ltd.

Gluon gravitational form factors of the proton in a light-front spectator model

We calculate the gluon gravitational form factors (GFFs) of the proton using a light-front spectator model based on soft-wall anti–de Sitter (AdS)/quantum chromodynamics (QCD), where the active parton is a gluon. The model parameters are determined by fitting the unpolarized gluon distribution function to the 3.0nlo dataset. Subsequently, we predict the polarized gluon distribution, finding consistency with global analyses. Our predictions for the gluon GFFs show good agreement with recent lattice QCD simulations and experimental extractions. Using these gluon GFFs, we compute the contribution of the gluon to the proton mass and mechanical radii. We also analyze the gluonic contribution to the two-dimensional Galilean densities, including energy density, radial and tangential pressure, isotropic pressure, and pressure anisotropy of the proton. Published by the American Physical Society 2025

A Cloud Computing Framework for Space Farming Data Analysis

This study presents a system framework by which cloud resources are utilized to analyze crop germination status in a 2U CubeSat. This research aims to address the onboard computing constraints in nanosatellite missions to boost space agricultural practices. Through the Espressif Simple Protocol for Network-on-Wireless (ESP-NOW) technology, communication between ESP-32 modules were established. The corresponding sensor readings and image data were securely streamed through Amazon Web Service Internet of Things (AWS IoT) to an ESP-NOW receiver and Roboflow. Real-time plant growth predictor monitoring was implemented through the web application provisioned at the receiver end. On the other hand, sprouts on germination bed were determined through the custom-trained Roboflow computer vision model. The feasibility of remote data computational analysis and monitoring for a 2U CubeSat, given its minute form factor, was successfully demonstrated through the proposed cloud framework. The germination detection model resulted in a mean average precision (mAP), precision, and recall of 99.5%, 99.9%, and 100.0%, respectively. The temperature, humidity, heat index, LED and Fogger states, and bed sprouts data were shown in real time through a web dashboard. With this use case, immediate actions can be performed accordingly when abnormalities occur. The scalability nature of the framework allows adaptation to various crops to support sustainable agricultural activities in extreme environments such as space farming.

The asymmetry $A_{LL}^{\cos2\phi}$ in the polarized proton-proton Drell-Yan process within TMD factorization

Abstract We study the $\cos2\phi$ azimuthal asymmetry in doubly longitudinally polarized proton-proton Drell-Yan collisions within the transverse momentum dependent factorization framework. The asymmetry arises from the convolution of the longitudinal transversity distribution $h_{1L}^{\perp}$ for both protons. Using the Bacchetta-Delcarro-Pisano-Radici-Signori parametrization for the nonperturbative Sudakov form factor and the Wandzura-Wilczek approximation for the collinear $h_{1L}^{\perp}$, we predict the double spin asymmetry $A_{LL}^{\cos2\phi}$ at RHIC and NICA kinematics. Our results demonstrate sensitivity to sea quark distributions, with the asymmetry reaching up to $25\%$ for maximal sea quark contributions. These predictions highlight the potential of polarized Drell-Yan measurements to probe sea quark dynamics and advance our understanding of nucleon structure.

VAIM-CFF: a variational autoencoder inverse mapper solution to Compton form factor extraction from deeply virtual exclusive reactions

We develop a new methodology for extracting Compton form factors (CFFs) from deeply virtual exclusive reactions such as the unpolarized DVCS cross section using a specialized inverse problem solver, a variational autoencoder inverse mapper (VAIM). The VAIM-CFF framework not only allows us access to a fitted solution set possibly containing multiple solutions in the extraction of all 8 CFFs from a single cross section measurement, but also accesses the lost information contained in the forward mapping from CFFs to cross section. We investigate various assumptions and their effects on the predicted CFFs such as cross section organization, number of extracted CFFs, use of uncertainty quantification technique, and inclusion of prior physics information. We then use dimensionality reduction techniques such as principal component analysis to visualize the missing physics information tracked in the latent space of the VAIM framework. Through re-framing the extraction of CFFs as an inverse problem, we gain access to fundamental properties of the problem not comprehensible in standard fitting methodologies: exploring the limits of the information encoded in deeply virtual exclusive experiments.

The gravitational form factors of hadrons from CFT in momentum space and the dilaton in perturbative QCD

We analyze the hard scattering amplitude of the gravitational form factors (GFFs) of hadrons at one-loop, in relation to their conformal field theory (CFT) description, within the framework of QCD factorization for hard exclusive processes at large momentum transfers. These form factors play an essential role in studying the quark and gluon angular momentum of the hadrons due to their relation to the Mellin moments of the Deeply virtual Compton scattering (DVCS) invariant amplitudes. Our analysis is performed using a diffeomorphism invariant approach, applying the formalism of the gravitational effective action and conformal symmetry in momentum space for the discussion of the quark and gluon contributions. The interpolating correlator in the hard scattering of any GFF is the non-Abelian TJJ (stress-energy/gluon/gluon) 3-point function at O(αs2), revealing an effective dilaton interaction in the t-channel due to the trace anomaly, in the form of a massless anomaly pole in the QCD hard scattering. We investigate the role of quarks, gauge-fixing and ghost contributions in the reconstruction of the hard scattering amplitude mediated by this interaction, performed in terms of its transverse traceless, longitudinal, and trace decomposition, as identified from CFT in momentum space (CFTp). We present a convenient parameterization of the hard scattering amplitude relevant for future experimental investigations of the DVCS/GFF amplitudes at the electron-ion collider at BNL.

Electromagnetic form factors of the transition from the Delta to the nucleon

Electromagnetic form factors of the transition from the Delta to the nucleon

Lattice QCD calculation of the η and η′ meson masses at the physical point using rooted staggered fermions

We present a lattice calculation of the η and η′ meson masses at the physical point and in the continuum limit, based on Nf=2+1+1 flavors of rooted staggered quarks. Our analysis includes gauge ensembles at the physical pion and kaon masses spread over six lattice spacings in the range [0.064–0.1315] fm. Our main results read mη=543.5(5.6) MeV and mη′=986(38) MeV, consistent with the experimental values. This is an important numerical test that supports the validity of the fourth root procedure used in the staggered quark formalism. This calculation was the first step toward extracting the pseudoscalar transition form factors of the η and η′ mesons that play a crucial role in the hadronic light-by-light contribution to the muon g−2. Published by the American Physical Society 2025

Study of the light scalar a0(980) through the decay D0→a0(980)−e+νe with a0(980)−→ηπ−

Using 7.93 fb−1 of e+e− collision data collected at a center-of-mass energy of 3.773 GeV with the BESIII detector, we present an analysis of the decay D0→ηπ−e+νe. The branching fraction of the decay D0→a0(980)−e+νe with a0(980)−→ηπ− is measured to be (0.86±0.17stat±0.05syst)×10−4. The decay dynamics of this process is studied with a single-pole parametrization of the hadronic form factor and the Flatté formula describing the a0(980) line shape in the differential decay rate. The product of the form factor f+a0(0) and the Cabibbo-Kobayashi-Maskawa matrix element |Vcd| is determined for the first time with the result f+a0(0)|Vcd|=0.126±0.013stat±0.003syst. Published by the American Physical Society 2025

Next generation High-Mobility 2D chalcogenides TFT for display backplane

Abstract The evolution of display backplane technologies has been driven by the relentless pursuit of higher form factor and superior performance coupled with lower power consumption. Current state-of-the-art backplane technologies based on amorphous Si, poly Si, and IGZO, face challenges in meeting the requirements of next-generation displays, including larger dimensions, higher refresh rates, increased pixel density, greater brightness, and reduced power consumption. In this context, 2D chalcogenides have emerged as promising candidates for thin-film transistors (TFTs) in display backplanes, offering advantages such as high mobility, low leakage current, mechanical robustness, and transparency. This comprehensive review explores the significance of 2D chalcogenides as materials for TFTs in next-generation display backplanes. We delve into the structural characteristics, electronic properties, and synthesis methods of 2D chalcogenides, emphasizing scalable growth strategies that are relevant to large-area display backplanes. Additionally, we discuss mechanical flexibility and strain engineering, crucial for the development of flexible displays. Performance enhancement strategies for 2D chalcogenide TFTs has been explored encompassing techniques in device engineering and geometry optimization keeping in mind the scaling considerations. Active-matrix implementation of 2D TFTs in various applications is also explored, benchmarking device performance on a large scale which is necessary aspect of TFTs used in display backplanes. Furthermore, latest development on the integration of 2D chalcogenide TFTs with different display technologies, such as OLED, quantum dot, and MicroLED displays has been reviewed in detail. Finally, challenges and opportunities in the field are discussed with a brief insight into emerging trends and research directions.

Exclusive semileptonic decays of D and Ds mesons into orbitally and radially excited states of strange and light mesons

Semileptonic decays of D and Ds mesons into orbitally and radially excited strange and light mesons are studied in detail within the framework of the relativistic quark model based on the quasipotential approach and quantum chromodynamics. The hadronic matrix elements of the weak current between meson states are calculated with the consistent account of relativistic effects including contributions of the intermediate negative energy states and boosts of the meson wave functions from the rest to moving reference frame. The invariant form factors that parametrize these matrix elements are obtained as the overlap integrals of the initial and final meson wave functions. Their dependence on the square of the transferred momentum q2 is explicitly determined within the whole accessible kinematic range. A convenient analytical approximation for numerical values of form factors is given. These form factors and helicity formalism are employed for the calculation of the differential and total semileptonic decay rates of charm mesons into excited strange and light mesons. Different asymmetry and polarization parameters are also evaluated. The obtained results are compared with other theoretical calculations and available experimental data. Reasonable agreement with experimentally measured semileptonic decay branching fractions and upper bounds is obtained. Published by the American Physical Society 2025

Wide-angle pion- Δ(1232) photoproduction

High-energy wide-angle photoproduction of πΔ final states is investigated within the handbag mechanism to twist-3 accuracy. In this approach the process amplitudes factorize in a hard partonic subprocess and in form factors which represent 1/x-moments of p−Δ transition generalized parton distributions (GPDs) at zero skewness. The subprocess, calculated to twist-3 accuracy, is the same as in pion photoproduction. The p−Δ GPDs are related to the proton-proton GPDs exploiting large-NC results. The proton-proton GPDs as well as the twist-2 and twist-3 pion distribution amplitudes appearing in the subprocess are taken from other work. Reasonable agreement with experiment is found in this almost parameter-free analysis. Published by the American Physical Society 2025

Optimizing pine tree stem volume models using artificial neural networks with minimal input variables

Historically, standard regression methods have been used to estimate forest biometric variables, utilizing parameters such as diameter at breast height (d1.3), tree height (h), and often a tree stem form factor. However, these methods often are front of challenges in handling the complex, non-linear relationships typical of biological data, like ground truth forest data, which can result in low accuracy, biases, and errors. In forest modeling research, the primary objective is to explore insights that will help develop a methodology capable of addressing the limitations and requirements of standard regression analysis. In this regard, the study investigates three computationally distinguished Artificial Neural Network (ANN) modeling approaches, such as the resilient back-propagation ANN, Levenberg–Marquardt ANN and the generalized regression ANN, to predict the stem volume (v) of European black pine (Pinus nigra) trees from the Karya region on Mount Olympus, Greece. Their performance was explored using a minimal set of ground-truth measurements, increasing the time efficiency of forest measurements. Among the tested models, the standard regression modeling exhibited the poorest adaptation as compared to the ANN modeling techniques. The non-parametric Levenberg–Marquardt ANN models effectively covered the full range of tree dimensions and achieved the highest accuracy of the stem volume of European black pine trees. The single-entry model achieved a Furnival index error of 0.1423, while the double-entry model had an error of 0.0967. Moreover, these models demonstrated excellent generalization capability, yielding Furnival index errors of 0.1314 (single-entry) and 0.0975 (double-entry) when predicting stem volumes.

Inclusive Design Process for User-Centered Wearable Products: A Case Study on Lumbar Support for Older Women with Chronic Low Back Pain

This study proposed an Inclusive Design Process Model for User-Centered Wearable Products (IDP-UW), suggesting opportunities, expected outcomes, and practical approaches guided by key design principles to ensure user inclusion and equitable access in the design process. To validate the model, an empirical case study was conducted to develop wearable lumbar support for older women with chronic low back pain. Iterative user interactions were integrated in the inclusive design process. The final prototype, developed through the process, incorporated form factors and materials reflecting the anthropometric characteristics and preferences of participants. Multidimensional evaluations confirmed that the final prototype demonstrated strong performance in walking balance, human error reduction, and subjective satisfaction. Moreover, participants expressed that their participation in the design process enriched their experience, fostering a sense of involvement, authority, achievement, and engagement. This study offers actionable insights addressing the needs of marginalized users, especially for wearable products where body-product interactions are crucial.

Nucleon gravitational form factors

A symmetry-preserving analysis of strong interaction quantum field equations is used to complete a unified treatment of pion, kaon, and nucleon electromagnetic and gravitational form factors. Findings include a demonstration that the pion near-core pressure is roughly twice that in the proton, so both are significantly greater than that of a neutron star; parton species separations of the nucleon’s three gravitational form factors, in which, inter alia, the glue-to-quark ratio for each form factor is seen to take the same constant value, independent of momentum transfer; and a determination of proton radii orderings, with the mechanical (normal force) radius being less than the mass-energy radius, which is less than the proton charge radius. This body of predictions should prove useful in an era of experiments that will enable them to be tested.