Search

We present a search for long-lived particles (LLPs) produced from kaon decay that decay to two muons inside the ICARUS neutrino detector. This channel would be a signal of hidden sector models that can address outstanding issues in particle physics such as the strong CP problem and the microphysical origin of dark matter. The search is performed with data collected in the Neutrinos at the Main Injector (NuMI) beam at Fermilab corresponding to $2.41\times 10^{20}$ protons-on-target. No new physics signal is observed, and we set world-leading limits on heavy QCD axions, as well as for the Higgs portal scalar among dedicated searches. Limits are also presented in a model-independent way applicable to any new physics model predicting the process $K\to \pi+S(\to\mu\mu)$, for a long-lived particle S. This result is the first search for new physics performed with the ICARUS detector at Fermilab. It paves the way for the future program of long-lived particle searches at ICARUS.

Spherical proportional counters (SPCs) are gaseous particle detectors sensitive to single ionization electrons in their target media, with large detector volumes and low background rates. The $\mbox{NEWS-G}$ collaboration employs this technology to search for low-mass dark matter, having previously performed searches with detectors at the Laboratoire Souterrain de Modane (LSM), including a recent campaign with a 135 cm diameter SPC filled with methane. While in situ calibrations of the detector response were carried out at the LSM, measurements of the mean ionization yield and fluctuations of methane gas in SPCs were performed using a 30 cm diameter detector. The results of multiple measurements taken at different operating voltages are presented. A UV laser system was used to measure the mean gas gain of the SPC, along with $\mathrm{^{37}Ar}$ and aluminum-fluorescence calibration sources. These measurements will inform the energy response model of future operating detectors., Comment: 11 pages, 8 figures

Motivated by the last experimental and theoretical advances in the analysis of possible baryonium resonances, the $X(1835)$ and their partners, we perform a constituent-quark-model based coupled-channels calculation of the proton-antiproton scattering in order to analyze the possible existence of bound states or near-threshold structures. The used $N\overline N$ potential is derived from a $G$-parity transformation of the quark-model-based $NN$ interaction which has described well deuteron properties, $NN$ phase shifts, and even hadron-hadron phenomenology. The additional $N\overline N$ annihilation is taken into account by a complex phenomenological potential whose real part is generated by one-pion and one-gluon exchange annihilation potentials and its imaginary part is an energy-independent potential of Gaussian form. Then, all the parameters of the interaction are constrained by the $NN$ sector except those determining the imaginary part of the annihilation potential. Our study concludes that the nucleon-antinucleon dynamics is complex and rich in scattering singularities near the proton-antiproton and neutron-antineutron thresholds., Comment: 7 pages, 2 figures, 3 tables

This paper reports on a measurement of electron-ion recombination in liquid argon in the ICARUS liquid argon time projection chamber (LArTPC). A clear dependence of recombination on the angle of the ionizing particle track relative to the drift electric field is observed. An ellipsoid modified box (EMB) model of recombination describes the data across all measured angles. These measurements are used for the calorimetric energy scale calibration of the ICARUS TPC, which is also presented. The impact of the EMB model is studied on calorimetric particle identification, as well as muon and proton energy measurements. Accounting for the angular dependence in EMB recombination improves the accuracy and precision of these measurements.

The NEWS-G direct detection experiment uses spherical proportional counters to search for light dark matter candidates. New results from a 10 day physics run with a $135\,\mathrm{cm}$ in diameter spherical proportional counter at the Laboratoire Souterrain de Modane are reported. The target consists of $114\,\mathrm{g}$ of methane, providing sensitivity to dark matter spin-dependent coupling to protons. New constraints are presented in the mass range $0.17$ to $1.2\,\mathrm{GeV/c^2}$, with a 90% confidence level cross-section upper limit of $30.9\,\mathrm{pb}$ for a mass of $0.76\,\mathrm{GeV/c^2}$., Comment: 7 pages, 3 figures

The ICARUS liquid argon time projection chamber (LArTPC) neutrino detector has been taking physics data since 2022 as part of the Short-Baseline Neutrino (SBN) Program. This paper details the equalization of the response to charge in the ICARUS time projection chamber (TPC), as well as data-driven tuning of the simulation of ionization charge signals and electronics noise. The equalization procedure removes non-uniformities in the ICARUS TPC response to charge in space and time. This work leverages the copious number of cosmic ray muons available to ICARUS at the surface. The ionization signal shape simulation applies a novel procedure that tunes the simulation to match what is measured in data. The end result of the equalization procedure and simulation tuning allows for a comparison of charge measurements in ICARUS between Monte Carlo simulation and data, showing good performance with minimal residual bias between the two.

The LHCb Collaboration announced in 2021 the discovery of a new tetraquark-like state, named $T_{cc}^+$, with minimum quark content $cc\bar u\bar d$, close to the $D^0D^{*+}$ threshold. This has motivated countless theoretical works trying to identify the dynamics which is responsible of the formation of such state; in particular, the one performed by us in Ref. \cite{Ortega:2022efc}, where a $D^0D^{*+}$ molecular candidate whose mass, width, scattering length and effective ranges are in reasonable agreement with experimental measurements. We explore herein the possibility of having $T_{cc}^+$ partners in all doubly-heavy tetraquark sectors, considering doubly represented light antiquarks $u$, $d$ or $s$, and taking into account all possible spin-parity quantum numbers. The computation is done using a constituent-quark-model based meson-meson coupled-channels framework which has been tested many times in the last fifteen years describing conventional heavy mesons and baryons, their coupling with hadron-hadron thresholds but also in exploring its application to compact multiquark structures. The advantage of using an approach with such a relatively large history is that it allows us to make predictions because all the parameters have already been constrained from our previous works. Then, from this perspective, we present a parameter-free model-dependent prediction of doubly-heavy tetraquarks that may be partners of the discovered $T_{cc}^+$ state., Comment: 8 pages, 1 figure, 6 tables. arXiv admin note: text overlap with arXiv:2211.06118

The $\Upsilon(10753)$ state has been recently observed by the Belle and Belle~II collaborations with enough global significance to motivate an assessment of the high-energy spectrum usually predicted by any reasonable \emph{na\"ive} quark model. In the framework of a constituent quark model which satisfactorily describes a wide range of properties of conventional hadrons containing heavy quarks, the quark-antiquark and meson-meson degrees of freedom have been incorporated with the goal of elucidating the influence of open-bottom meson-meson thresholds into the $\Upsilon$ states whose masses are within the energy range of the $\Upsilon(10753)$'s mass. It is well known that such effects could be relevant enough as to generate dynamically new states and thus provide a plausible explanation of the nature of the $\Upsilon(10753)$ state. In particular, we have performed a coupled-channels calculation in which the bare states $\Upsilon(4S)$, $\Upsilon(3D)$, $\Upsilon(5S)$ and $\Upsilon(4D)$ are considered together with the threshold channels $B\bar{B}$, $B\bar{B}^\ast$, $B^\ast \bar{B}^\ast$, $B_s\bar{B}_s$, $B_s\bar{B}_s^\ast$ and $B_s^\ast \bar{B}_s^\ast$. Among the results we have described, the following conclusions are of particular interest: (i) a richer complex spectrum is gained when thresholds are present and bare bound states are sufficiently non-relativistic; (ii) those poles obtained in the complex energy plane do not have to appear as simple peaks in the relevant cross sections; and (iii) the $\Upsilon(10750)$ candidate is interpreted as a dressed hadronic resonance whose structure is an equally mixture of a conventional $b\bar b$ state and $B^\ast \bar B^\ast$ molecule., Comment: 11 pages, 2 figures, 6 tables

Strong solar magnetic fields are the energy source of intense flares and energetic coronal mass ejections of space weather importance. The key issue is the difficulty in predicting the occurrence time and location of strong solar eruptions, those leading to high impact space weather disturbances at the near-Earth environment. Here, we report regular solar mapping made at X-band (8.1 -- 9.2 GHz) with the Arecibo 12-m radio telescope. This has demonstrated its potential for identifying active regions, about one half to a day in advance, when they rotate on to the central meridian of the Sun, and predicting the strongest flares and coronal mass ejections directed towards the Earth. Results show (i) a good correlation between the temporal evolution of brightness temperature of active regions and their magnetic configurations; (ii) the ability of the mapping data to provide a better picture of the formation sites of active regions and to accurately track their evolution across the solar disk, giving forewarning of intense solar eruptions leading to severe space weather consequences; (iii) the importance of long-term monitoring of the Sun at X-band for understanding the complex three-dimensional evolution of solar features as a function of solar activity. The key point in this study is the identification of the magnetic properties of active regions on the solar disk to aid in improving forecast strategies for extreme space-weather events., Comment: 27 pages, 17 figures, submitted to Solar Physics

Using proton-proton collisions at centre-of-mass energies $7$, $8$, and $13$ TeV, with a total integrated luminosity of $9\,\text{fb}^{-1}$, the LHCb collaboration has performed amplitude analyses of the $B^+\to D^+D^-K^+$, $B^+\to D^- D_s^+ \pi^+$ and $B^0\to \bar{D}^0 D_s^+ \pi^-$ decays, observing that new $T_{cs}$ and $T_{c\bar s}$ resonances are required in order to explain the experimental data. These signals could be the first observation of tetraquark candidates that do not contain a heavy quark-antiquark pair; in fact, they consist of four different flavours of quarks, one of which is a doubly charged open-charm state. We present herein an analysis of the $T_{cs}$ and $T_{c\bar s}$ states, which is an extension of our recently published study of similar $T_{cc}^+$ exotic candidates. Our theoretical framework is a constituent-quark-model-based coupled-channels calculation of $qq^\prime \bar s \bar c$ and $cq\bar s\bar q^{\prime}$ tetraquark sectors for $T_{cs}$ and $T_{c\bar s}$ structures, respectively. We explore the nature, and pole position, of the singularities that appear in the scattering matrix with spin-parity quantum numbers: $J^P=0^\pm$, $1^\mp$, and $2^\pm$. The constituent quark model has been widely used in the heavy quark sector, and thus all model parameters are already constrained from previous works. This makes our predictions robust and parameter-free. We find many singularities in the solution of various scattering-matrix problems which are either virtual states or resonances, but not bound states. Some of them fit well with the experimental observations of the spin-parity, mass and width of $T_{cs}$ and $T_{c\bar s}$ candidates, and thus tentative assignments are made; however, with caution, because the experimental Breit-Wigner parameters are related to the pole characteristics., Comment: 10 pages, 4 tables

In this work we develop a theory of Stieltjes-analytic functions. We first define the Stieltjes monomials and polynomials and we study them exhaustively. Then, we introduce the Stieltjes analytic functions locally, as an infinite series of these Stieltjes monomials and we study their properties in depth and how they relate to higher order Stieltjes differentiation. We define the exponential series and prove that it solves the first order linear problem. Finally, we apply the theory to solve higher order linear homogeneous Stieltjes differential equations with constant coefficients.

We present the conceptual design and the physics potential of DarkSPHERE, a proposed 3 m in diameter spherical proportional counter electroformed underground at the Boulby Underground Laboratory. This effort builds on the R&D performed and experience acquired by the NEWS-G Collaboration. DarkSPHERE is primarily designed to search for nuclear recoils from light dark matter in the 0.05--10 GeV mass range. Electroforming the spherical shell and the implementation of a shield based on pure water ensures a background level below 0.01 dru. These, combined with the proposed helium-isobutane gas mixture, will provide sensitivity to the spin-independent nucleon cross-section of $2\times 10^{-41} (2\times 10^{-43})$ cm$^2$ for a dark matter mass of $0.1 (1)$ GeV. The use of a hydrogen-rich gas mixture with a natural abundance of $^{13}$C provides sensitivity to spin-dependent nucleon cross-sections more than two orders of magnitude below existing constraints for dark matter lighter than 1 GeV. The characteristics of the detector also make it suitable for searches of other dark matter signatures, including scattering of MeV-scale dark matter with electrons, and super-heavy dark matter with masses around the Planck scale that leave extended ionisation tracks in the detector., Comment: 19 pages, 14 figures

The vulnerabilities of fingerprint-based recognition systems to direct attacks with and without the cooperation of the user are studied. Two different systems, one minutiae-based and one ridge feature-based, are evaluated on a database of real and fake fingerprints. Based on the fingerprint images quality and on the results achieved on different operational scenarios, we obtain a number of statistically significant observations regarding the robustness of the systems., Comment: Published at Springer Journal of Telecommunication Systems, Special Issue of Biometrics Systems & Applications

One of the challenges in virtual environments is the difficulty users have in interacting with these increasingly complex systems. Ultimately, endowing machines with the ability to perceive users emotions will enable a more intuitive and reliable interaction. Consequently, using the electroencephalogram as a bio-signal sensor, the affective state of a user can be modelled and subsequently utilised in order to achieve a system that can recognise and react to the user's emotions. This paper investigates features extracted from electroencephalogram signals for the purpose of affective state modelling based on Russell's Circumplex Model. Investigations are presented that aim to provide the foundation for future work in modelling user affect to enhance interaction experience in virtual environments. The DEAP dataset was used within this work, along with a Support Vector Machine and Random Forest, which yielded reasonable classification accuracies for Valence and Arousal using feature vectors based on statistical measurements and band power from the \'z, \b{eta}, \'z, and \'z\'z waves and High Order Crossing of the EEG signal., Comment: Published at Personal and Ubiquitous Computing Journal (PUC)

The European Organization for Nuclear Research (CERN) has recently approved a world-unique QCD facility in which an updated version of the external M2 beam line of the CERN SPS in conjunction with a universal spectrometer of the COMPASS experiment is used. One of its main goals is to use highly intense and energetic kaon beams to map out the complete spectrum of excited kaons with an unprecedented precision; having a broad impact not only on low-energy QCD phenomenology, but also on many high-energy particle processes where excited kaons appear, such as the study of CP violation in heavy-meson decays studied at LHCb and Belle~II. In support of the experimental effort, the kaon spectrum is computed herein using a constituent quark model which has been successfully applied to a wide range of hadronic observables, from light to heavy quark sectors, and thus the model parameters are completely constrained. The model's prediction can be used as a template against which to compare the already collected data and future experimental findings, in order to distinguish between conventional and exotic kaon states. We also compare our results with those available in the literature in order to provide some general statements, common to all calculations., Comment: 11 pages, 1 figure, 13 tables

This paper describes a solution for the efficient management of revocation in vehicular ad-hoc networks, for both certificate-based and identity-based authentication. It proposes the use of an authenticated data structure based on a dynamic hash tree, which is a perfect $k$-ary tree, together with a new version of the SHA-3 hash function. This combination allows optimizing search and insertion operations in the tree. Consequently, the proposal is very useful both when vehicular networks are widely used, and in urban environments. Simulation results are promising and confirm this hypothesis., Comment: arXiv admin note: substantial text overlap with arXiv:2208.05343

On 2$^{nd}$ October 2012 the NIST (National Institute of Standards and Technology) in the United States of America announced the new hashing algorithm which will be adopted as standard from now on. Among a total of 73 candidates, the winner was Keccak, designed by a group of cryptographers from Belgium and Italy. The public selection of a new standard of cryptographic hash function SHA (Secure Hash Algorithm) took five years. Its object is to generate a hash a fixed size from a pattern with arbitrary length. The first selection on behalf of NIST on a standard of this family took place in 1993 when SHA-1 was chosen, which later on was replaced by SHA-2. This paper is focused on the analysis both from the point of view of security and the implementation of the Keccak function, which is the base of the new SHA-3 standard. In particular, an implementation in the mobile platform Android is presented here, providing the first known external library in this mobile operating system so that any developer could use the new standard hashing. Finally, the new standard in applications in the Internet of Things is analysed.

A vehicular ad-hoc network is a type of communication network where the nodes are vehicles. Their aim is to manage traffic efficiently in order to prevent unwanted events such as accidents, jams, etc. The research on this type of networks assumes the use of additional infrastructure installed on the roads, and special devices installed in vehicles. In this paper we propose a novel solution for the deployment of vehicular networks, which uses only existing smartphones with technologies such as Wi-Fi, GPS and Bluetooth. This approach will save the costs of road infrastructure deployment and extra vehicles devices, making it possible to deploy the first real-world vehicular ad-hoc network with a low cost. In particular, the developed implementation of the proposal for the Symbian platform is here examined in full detail.

The New Experiments With Spheres-Gas (NEWS-G) collaboration intends to achieve $\mathrm{sub-GeV/c^{2}}$ Weakly Interacting Massive Particles (WIMPs) detection using Spherical Proportional Counters (SPCs). SPCs are gaseous detectors relying on ionization with a single ionization electron energy threshold. The latest generation of SPC for direct dark matter searches has been installed at SNOLAB in Canada in 2021. This article details the different processes involved in the fabrication of the NEWS-G experiment. Also outlined in this paper are the mitigation strategies, measurements of radioactivity of the different components, and estimations of induced background event rates that were used to quantify and address detector backgrounds., Comment: 18 pages, 9 figures, 5 tables, to be published

The properties of the $B_c$-meson family ($c\bar b$) are still not well determined experimentally because the specific mechanisms of formation and decay remain poorly understood. Unlike heavy quarkonia, i.e. the hidden heavy quark-antiquark sectors of charmonium ($c\bar c$) and bottomonium ($b\bar b$), the $B_c$-mesons cannot annihilate into gluons and they are, consequently, more stable. The excited $B_c$ states, lying below the lowest strong-decay $BD$-threshold, can only undergo through radiative decays and hadronic transitions to the $B_c$ ground state, which then decays weakly. As a result of this, a rich spectrum of narrow excited states below the $BD$-threshold appear, whose total widths are two orders of magnitude smaller than those of the excited levels of charmonium and bottomonium. In a different article, we determined bottom-charmed meson masses using a non-relativistic constituent quark model which has been applied to a wide range of hadron physical observables, and thus the model parameters are completely constrained. Herein, continuing to our study of the $B_c$ sector, we calculate the relevant radiative decay widths and hadronic transition rates between $c\bar b$ states which are below $BD$-threshold. This shall provide the most promising signals for discovering excited $B_c$ states that are below the lowest strong-decay $BD$-threshold. Finally, our results are compared with other models to measure the reliability of the predictions and point out differences., Comment: 13 pages, 9 tables. arXiv admin note: text overlap with arXiv:1601.05093

Imaging using millimeter waves (mmWs) has many advantages including the ability to penetrate obscurants such as clothes and polymers. After having explored shape information retrieved from mmW images for person recognition, in this work we aim to gain some insight about the potential of using mmW texture information for the same task, considering not only the mmW face, but also mmW torso and mmW wholebody. We report experimental results using the mmW TNO database consisting of 50 individuals based on both hand-crafted and learned features from Alexnet and VGG-face pretrained Convolutional Neural Networks (CNN) models. First, we analyze the individual performance of three mmW body parts, concluding that: i) mmW torso region is more discriminative than mmW face and the whole body, ii) CNN features produce better results compared to hand-crafted features on mmW faces and the entire body, and iii) hand-crafted features slightly outperform CNN features on mmW torso. In the second part of this work, we analyze different multi-algorithmic and multi-modal techniques, including a novel CNN-based fusion technique, improving verification results to 2% EER and identification rank-1 results up to 99%. Comparative analyses with mmW body shape information and face recognition in the visible and NIR spectral bands are also reported., Comment: Published at IEEE Transactions on Biometrics, Behavior, and Identity Science

The lack of resolution has a negative impact on the performance of image-based biometrics. While many generic super-resolution methods have been proposed to restore low-resolution images, they usually aim to enhance their visual appearance. However, a visual enhancement of biometric images does not necessarily correlate with a better recognition performance. Reconstruction approaches need thus to incorporate specific information from the target biometric modality to effectively improve recognition. This paper presents a comprehensive survey of iris super-resolution approaches proposed in the literature. We have also adapted an Eigen-patches reconstruction method based on PCA Eigen-transformation of local image patches. The structure of the iris is exploited by building a patch-position dependent dictionary. In addition, image patches are restored separately, having their own reconstruction weights. This allows the solution to be locally optimized, helping to preserve local information. To evaluate the algorithm, we degraded high-resolution images from the CASIA Interval V3 database. Different restorations were considered, with 15x15 pixels being the smallest resolution. To the best of our knowledge, this is among the smallest resolutions employed in the literature. The framework is complemented with six public iris comparators, which were used to carry out biometric verification and identification experiments. Experimental results show that the proposed method significantly outperforms both bilinear and bicubic interpolation at very low-resolution. The performance of a number of comparators attains an impressive Equal Error Rate as low as 5%, and a Top-1 accuracy of 77-84% when considering iris images of only 15x15 pixels. These results clearly demonstrate the benefit of using trained super-resolution techniques to improve the quality of iris images prior to matching., Comment: Published at IEEE Access

Coherent elastic neutrino-nucleus scattering (CE$\nu$NS) is a process in which neutrinos scatter on a nucleus which acts as a single particle. Though the total cross section is large by neutrino standards, CE$\nu$NS has long proven difficult to detect, since the deposited energy into the nucleus is $\sim$ keV. In 2017, the COHERENT collaboration announced the detection of CE$\nu$NS using a stopped-pion source with CsI detectors, followed up the detection of CE$\nu$NS using an Ar target. The detection of CE$\nu$NS has spawned a flurry of activities in high-energy physics, inspiring new constraints on beyond the Standard Model (BSM) physics, and new experimental methods. The CE$\nu$NS process has important implications for not only high-energy physics, but also astrophysics, nuclear physics, and beyond. This whitepaper discusses the scientific importance of CE$\nu$NS, highlighting how present experiments such as COHERENT are informing theory, and also how future experiments will provide a wealth of information across the aforementioned fields of physics., Comment: contribution to Snowmasss 2021. Contact authors: P. S. Barbeau, R. Strauss, L. E. Strigari

Many low-threshold experiments observe sharply rising event rates of yet unknown origins below a few hundred eV, and larger than expected from known backgrounds. Due to the significant impact of this excess on the dark matter or neutrino sensitivity of these experiments, a collective effort has been started to share the knowledge about the individual observations. For this, the EXCESS Workshop was initiated. In its first iteration in June 2021, ten rare event search collaborations contributed to this initiative via talks and discussions. The contributing collaborations were CONNIE, CRESST, DAMIC, EDELWEISS, MINER, NEWS-G, NUCLEUS, RICOCHET, SENSEI and SuperCDMS. They presented data about their observed energy spectra and known backgrounds together with details about the respective measurements. In this paper, we summarize the presented information and give a comprehensive overview of the similarities and differences between the distinct measurements. The provided data is furthermore publicly available on the workshop's data repository together with a plotting tool for visualization., Comment: 44 pages, 20 figures; Editors: A. Fuss, M. Kaznacheeva, F. Reindl, F. Wagner; updated copyright statements and funding information

The amount of energy released by a nuclear recoil ionizing the atoms of the active volume of detection appears "quenched" compared to an electron of the same kinetic energy. This different behavior in ionization between electrons and nuclei is described by the Ionization Quenching Factor (IQF) and it plays a crucial role in direct dark matter searches. For low kinetic energies (below $50~\mathrm{keV}$), IQF measurements deviate significantly from common models used for theoretical predictions and simulations. We report measurements of the IQF for proton, an appropriate target for searches of Dark Matter candidates with a mass of approximately 1 GeV, with kinetic energies in between $2~\mathrm{keV}$ and $13~\mathrm{keV}$ in $100~\mathrm{mbar}$ of methane. We used the Comimac facility in order to produce the motion of nuclei and electrons of controlled kinetic energy in the active volume, and a NEWS-G SPC to measure the deposited energy. The Comimac electrons are used as reference to calibrate the detector with 7 energy points. A detailed study of systematic effects led to the final results well fitted by $\mathrm{IQF}~(E_K)= E_K^\alpha~/~(\beta + E_K^\alpha)$ with $\alpha=0.70\pm0.08$ and $\beta = 1.32\pm0.17$. In agreement with some previous works in other gas mixtures, we measured less ionization energy than predicted from SRIM simulations, the difference reaching $33\%$ at $2~\mathrm{keV}$, Comment: 12 pages, 9 figures

Contact lenses have traditionally been used for vision correction applications. Recent advances in microelectronics and nanofabrication on flexible substrates have now enabled sensors, circuits and other essential components to be integrated on a small contact lens platform. This has opened up the possibility of using contact lenses for a range of human-machine interaction applications including vision assistance, eye tracking, displays and health care. In this article, we systematically review the range of smart contact lens materials, device architectures and components that facilitate this interaction for different applications. In fact, evidence from our systematic review demonstrates that these lenses can be used to display information, detect eye movements, restore vision and detect certain biomarkers in tear fluid. Consequently, whereas previous state-of the-art reviews in contact lenses focused exclusively on biosensing, our systematic review covers a wider range of smart contact lens applications in HMI. Moreover, we present a new method of classifying the literature on smart contact lenses according to their six constituent building blocks, which are the sensing, energy management, driver electronics, communications, substrate and the interfacing modules. Based on recent developments in each of these categories, we speculate the challenges and opportunities of smart contact lenses for human-machine interaction. Moreover, we propose a novel self-powered smart contact lens concept with integrated energy harvesters, sensors and communication modules to enable autonomous operation. Our review is therefore a critical evaluation of current data and is presented with the aim of guiding researchers to new research directions in smart contact lenses., Comment: This work has been submitted to the IEEE for possible publication

In this article we explore under which conditions on the interior function the composition of functions is measurable. We also study the sharpness of the result by providing a counterexample for weaker hypotheses., Comment: 9 pages

Kaluza-Klein (KK) axions appear in theories with extra dimensions as higher mass, significantly shorter lifetime, excitations of the Peccei-Quinn axion. When produced in the Sun, they would remain gravitationally trapped in the solar system, and their decay to a pair of photons could provide an explanation of the solar corona heating problem. A low-density detector would discriminate such a signal from the background, by identifying the separation of the interaction point of the two photons. The NEWS-G collaboration uses large volume Spherical Proportional Counters, gas-filled metallic spheres with a spherical anode in their centre. After observation of a single axionlike event in a 42 day long run with the SEDINE detector, a $90\%$ C.L. upper limit of $g_{a\gamma\gamma}<8.99\cdot10^{-13}\,GeV^{-1}$ is set on the axion-photon coupling for a KK axion density on Earth of $n_{a}=4.07\cdot10^{13}\,m^{-3}$ and two extra dimensions of size $R = 1\,eV^{-1}$., Comment: 19 pages, 11 figures. Updated with additional details requested during review for publication in PRD and mild relaxation of final constraint

The NEWS-G collaboration uses Spherical Proportional Counters (SPCs) to search for weakly interacting massive particles (WIMPs). In this paper, we report the first measurements of the nuclear quenching factor in neon gas at \SI{2}{bar} using an SPC deployed in a neutron beam at the TUNL facility. The energy-dependence of the nuclear quenching factor is modelled using a simple power law: $\alpha$E$_{nr}^{\beta}$; we determine its parameters by simultaneously fitting the data collected with the detector over a range of energies. We measured the following parameters in Ne:CH$_{4}$ at \SI{2}{bar}: $\alpha$ = 0.2801 $\pm$ 0.0050 (fit) $\pm$ 0.0045 (sys) and $\beta$ = 0.0867 $\pm$ 0.020 (fit) $\pm$ 0.006(sys). Our measurements do not agree with expected values from SRIM or Lindhard theory. We demonstrated the feasibility of performing quenching factor measurements at sub-keV energies in gases using SPCs and a neutron beam.

We introduce a digital twin of the classical compartmental SIR (Susceptible, Infected, Recovered) epidemic model and study the interrelation between the digital twin and the system. In doing so, we use Stieltjes derivatives to feed the data from the real system to the virtual model which, in return, improves it in real time. As a byproduct of the model, we present a precise mathematical definition of solution to the problem. We also analyze the existence and uniqueness of solutions, introduce the concept of Main Digital Twin and present some numerical simulations with real data of the COVID-19 epidemic, showing the accuracy of the proposed ideas.

The discovery of a new charged structure in the $K^+$ recoil-mass spectrum near the $D^-_s D^{*0}/D^{*-}_sD^0$ threshold, dubbed $Z_{cs}(3985)^-$, reinforce the idea that the structure of hadrons goes beyond the naive $qqq$ and the $q\bar q$ structures. The existence of this state, with quark content $c\bar c s\bar u$, can be expected from the well-established $Z_c(3900)^\pm$ and $Z_c(4020)$ states using SU(3) flavor symmetry. The $Z_c$ structures have been explained using the chiral constituent quark model in a coupled-channels calculation and, in this work, we undertake the study of the $Z_{cs}(3985)^-$ using the same model. We are able to reproduce the $K^+$ recoil-mass spectrum without any fine tuning of the model parameters. The study of the analytical structure of the S-matrix allows us to conclude that the structure is due to the presence of one virtual pole. A second state, the SU(3) flavor partner of the $Z_c(4020)$ is predicted at $\sim\!\! 4110$ MeV/$c^2$. New states in the hidden bottom strange sector are also predicted., Comment: 7 pages, 5 figures, 1 table. arXiv admin note: text overlap with arXiv:1808.00914

New Experiments with Spheres-Gas (NEWS-G) is a dark matter direct detection experiment that will operate at SNOLAB (Canada). Similar to other rare-event searches, the materials used in the detector construction are subject to stringent radiopurity requirements. The detector features a 140-cm diameter proportional counter comprising two hemispheres made from commercially sourced 99.99% pure copper. Such copper is widely used in rare-event searches because it is readily available, there are no long-lived Cu radioisotopes, and levels of non-Cu radiocontaminants are generally low. However, measurements performed with a dedicated 210Po alpha counting method using an XIA detector confirmed a problematic concentration of 210Pb in bulk of the copper. To shield the proportional counter's active volume, a low-background electroforming method was adapted to the hemispherical shape to grow a 500-$\mu$m thick layer of ultra-radiopure copper to the detector's inner surface. In this paper the process is described, which was prototyped at Pacific Northwest National Laboratory (PNNL), USA, and then conducted at full scale in the Laboratoire Souterrain de Modane in France. The radiopurity of the electroplated copper was assessed through Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Measurements of samples from the first (second) hemisphere give 68% confidence upper limits of <0.58 $\mu$Bq/kg (<0.24 $\mu$Bq/kg) and <0.26 $\mu$Bq/kg (<0.11 $\mu$Bq/kg) on the 232Th and 238U contamination levels, respectively. These results are comparable to previously reported measurements of electroformed copper produced for other rare-event searches, which were also found to have low concentration of 210Pb consistent with the background goals of the NEWS-G experiment., Comment: 11 pages, 11 figures, 3 tables

Although the spectra of heavy quarkonium systems has been successfully explained by certain QCD motivated potential models, their strong decays are difficult to deal with. We perform a microscopic calculation of charmonium strong decays using the same constituent quark model which successfully describes the $c\bar{c}$ meson spectrum. We compare the numerical results with the $^{3}P_{0}$ and the experimental data. Comparison with other predictions from similar models are included., Comment: Contribution to the proceedings of the XIV International Conference on Hadron Spectroscopy (HADRON 2011); 13-17 June 2011, Munich, Germany

The BaBar Collaboration has recently reported branching fractions for semileptonic decays of the $B$ meson into final states with charged and neutral $D_{1}(2420)$ and $D_{2}^{\ast}(2460)$, two narrow orbitally excited charmed mesons. We evaluate these branching fractions within the framework of a constituent quark model in two steps, one which involves a semileptonic decay and the other one mediated by a strong process. Our results are in agreement with the experimental data., Comment: Contribution to the proceedings of the XIV International Conference on Hadron Spectroscopy (HADRON 2011); 13-17 June 2011, Munich, Germany