Lattice calaulation of χc0→ 2γ decay width

We perform a lattice QCD calculation of the $\chi_{c0} \rightarrow 2\gamma$ decay width using a model-independent method which does not require a momentum extrapolation of the corresponding off-shell form factors. The simulation is performed on ensembles of $N_f=2$ twisted mass lattice QCD gauge configurations with three different lattice spacings. After a continuum extrapolation, the decay width is obtained to be $\Gamma_{\gamma\gamma}(\chi_{c0})=3.65(83)_{\mathrm{stat}}(21)_{\mathrm{lat.syst}}(66)_{\mathrm{syst}}\, \textrm{keV}$. Albeit this large statistical error, our result is compatible with the experimental results within 1.3$\sigma$. Potential improvements of the lattice calculation in the future are also discussed. 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.

Recent Advances in Wearable Optical Sensors Automation Powered by Battery Versus Skin-Like Battery-Free Devices for Personal Healthcare - A Review

Currently, old-style personal medicare techniques rely mostly on traditional methods, such as cumbersome tools and complicated processes, which can be time-consuming and inconvenient in some circumstances. Furthermore, such old methods need the use of heavy equipment, blood draws, and traditional bench-top testing procedures. Invasive ways of acquiring test samples can potentially cause patients discomfort and anguish. Wearable sensors, on the other hand, may be attached to numerous body areas to capture diverse biochemical and physiological characteristics as a developing analytical tool. Physical, chemical, and biological data transferred via the skin is used to monitor health in various circumstances. Wearable sensors can assess the aberrant conditions of the physical or chemical components of the human body in real-time, exposing the body state in time, thanks to unintrusive sampling and high accuracy. Most commercially available wearable gadgets are mechanically hard components attached to bands and worn on the wrist, with form factors ultimately constrained by the size and weight of the batteries required for the power supply. Wearable gadgets with “skin-like” qualities are a new type of automation that is only starting to make its way out of research labs and into pre-commercial prototypes. In this paper, we studied the recent advancement in battery-powered wearable sensors established on optical phenomena and skin-like battery-free sensors which brings a breakthrough in wearable sensing automation.

Highly Reliable Flexible Device With Charge Compensation Layer

Flexible devices fabricated with polyimide (PI) substrate are crucial for foldable, rollable, or stretchable products in various applications. However, inherent technical challenges remain in mobile charge induced device instabilities and image retention, significantly hindering future technologies. We introduced a new barrier material, SiCOH, into the backplane of amorphous indium-gallium-zinc-oxide (a–IGZO) thin-film transistors (TFTs) that were then implemented into production-level flexible panels. We found that the SiCOH layer effectively compensates the surface charging induced by fluorine ions at the interface between the PI substrate and the barrier layer under bias stress, thereby preventing abnormal positive Vth shifts and image disturbance. The a–IGZO TFTs, metal-insulator-metal (MIM), and metal-insulator-semiconductor (MIS) capacitors with the SiCOH layer demonstrate reliable device performance, Vth shifts, and capacitance changes with an increase in the gate bias stress. A flexible device with SiCOH enables the suppression of abnormal Vth shifts associated with PI and plays a vital role in the degree of image sticking phenomenon. This work provides new inspirations to creating much improved process integrity and paves the way for expediting versatile form-factors.

Time-like Proton Form Factors with Initial State Radiation Technique

Electromagnetic form factors are fundamental quantities describing the internal structure of hadrons. They can be measured with scattering processes in the space-like region and annihilation processes in the time-like region. The two regions are connected by crossing symmetry. The measurements of the proton electromagnetic form factors in the time-like region using the initial state radiation technique are reviewed. Recent experimental studies have shown that initial state radiation processes at high luminosity electron-positron colliders can be effectively used to probe the electromagnetic structure of hadrons. The BABAR experiment at the B-factory PEP-II in Stanford and the BESIII experiment at BEPCII (an electron positron collider in the τ-charm mass region) in Beijing have measured the time-like form factors of the proton using the initial state radiation process e+e−→pp¯γ. The two kinematical regions where the photon is emitted from the initial state at small and large polar angles have been investigated. In the first case, the photon is in the region not covered by the detector acceptance and is not detected. The Born cross section and the proton effective form factor have been measured over a wide and continuous range of the the momentum transfer squared q2 from the threshold up to 42 (GeV/c)2. The ratio of electric and magnetic form factors of the proton has been also determined. In this report, the theoretical aspect and the experimental studies of the initial state radiation process e+e−→pp¯γ are described. The measurements of the Born cross section and the proton form factors obtained in these analyses near the threshold region and in the relatively large q2 region are examined. The experimental results are compared to the predictions from theory and models. Their impact on our understanding of the nucleon structure is discussed.

Electromagnetic Form Factors of Σ Hyperons

Electromagnetic form factors (EMFFs) are fundamental observable of baryons that intimately related to their internal structure and dynamics, where the EMFFs of hyperons provide valuable insight into the behavior of the strangeness. The EMFFs of hyperons can also help to understand those of nucleons as they are connected with the flavor SU(3) symmetry. The EMFFs of nucleons can be measured in both spacelike and timelike regions. However, it is difficult to probe the EMFFs of hyperons in spacelike region due to the unstable nature of hyperons. By means of electron-positron annihilation, the EMFFs of hyperons in timelike region is accessible via the production of hyperon-antihyperon pair. The timelike EMFFs of the isospin triplet Σ hyperons measured at Babar, CLEO-c and BESIII experiments are reviewed in this paper. Besides, the relevant theoretical discussion based on the experimental results are also presented.

Electromagnetic Form Factor of Doubly-Strange Hyperon

The standard model of particle physics is a well-tested theoretical framework, but there are still some issues that deserve experimental and theoretical investigation. The Ξ resonances with strangeness S=−2, the so-called doubly-strange hyperon, can provide important information to further test the standard model by studying their electromagnetic form factors, such as probing the limitation of the quark models and spotting unrevealed aspects of the QCD description of the structure of hadron resonances. In this work, we review some recent studies of the electromagnetic form factors on doubly-strange hyperons in pair production from positron–electron annihilation experiment.

Challenge-Driven Printing Strategies Toward High-Performance Solid-State Lithium Batteries

Solid-state lithium batteries (SSLBs) are promising candidates for replacing traditional liquid-based Li-ion batteries and revolutionizing battery systems for electric vehicles and portable devices. However, longstanding issues such as form factors,...

Electromagnetic finite-size effects beyond the point-like approximation

We present a model-independent and relativistic approach to analytically derive electromagnetic finite-size effects beyond the point-like approximation. The key element is the use of electromagnetic Ward identities to constrain vertex functions, and structure-dependence appears via physical form-factors and their derivatives. We apply our general method to study the leading finitesize structure-dependence in the pseudoscalar mass (at order 1/L3) as well as in the leptonic decay amplitudes of pions and kaons (at order 1/L2). Knowledge of the latter is essential for Standard Model precision tests in the flavour physics sector from lattice simulations.