The High Energy Accelerator Research Organization (高エネルギー加速器研究機構, Kō Enerugī Kasokuki Kenkyū Kikō), known as KEK, is a Japanese organization whose purpose is to operate the largest particle physics laboratory in Japan, situated in Tsukuba, Ibaraki prefecture. It was established in 1997. The term "KEK" is also used to refer to the laboratory itself, which employs approximately 695 employees. KEK's main function is to provide the particle accelerators and other infrastructure needed for high-energy physics, material science, structural biology, radiation science, computing science, nuclear transmutation and so on. Numerous experiments have been constructed at KEK by the internal and international collaborations that have made use of them. Makoto Kobayashi, emeritus professor at KEK, is known globally for his work on CP-violation, and was awarded the 2008 Nobel Prize in Physics.Coordinates: 36°08′55″N 140°04′37″E / 36.14861°N 140.07694°E / 36.14861; 140.
Electrocatalytic water splitting represents a sustainable and efficient approach for producing high-purity hydrogen, playing an increasingly pivotal role in addressing global energy sustainability challenges. However, dynamic and complex electrocatalytic processes pose significant obstacles to unraveling electrocatalytic mechanisms and advancing catalyst design. This review first discusses fundamental principles for conducting reliable in situ/operando synchrotron radiation (SR) spectroscopic measurements in electrocatalytic systems, proposing guidelines for standardizing practices across the community. Then, cutting-edge in situ/operando SR-based spectroscopic techniques applied in electrocatalytic water splitting are systematically examined, highlighting their distinctive advantages while critically evaluating inherent methodological limitations. Moving beyond conventional single-technique approaches, we focus on complementary probes based on in situ/operando multi-SR spectroscopic technologies to achieve panoramic visualization of the dynamic evolution for the water splitting process, spanning from the atomic and molecular scales to the electronic level. Finally, key bottlenecks and frontier research opportunities are outlined, aiming to inspire a paradigm shift from fragmented analysis toward integrated, system-level mechanistic understanding in electrocatalytic water splitting.
The muon g-2/EDM experiment at J-PARC is designed to precisely measure the muon's magnetic moment and electric dipole moment, driven by discrepancies between theory and previous experiments. One of the key challenges in the experiment is the fast reconstruction of positron tracks from multiple muon decays within a short time span causing an event pileup. Results from simulation studies have shown expected results in terms of efficiency and accuracy of track reconstruction. However, the execution time for the entire analysis chain is prohibitively long to be deployed in the experiment. Specifically, preliminary estimations suggest a requirement of 10 & times; speedup of the track-finding routine. In this context, we explore a GPU-based solution to accelerate track-finding through parallel processing and present the implementation details and the results of our study for different pileup conditions. The results indicate that the GPU solution meets our expectation in terms of execution speed without compromising on the reconstruction efficiency.
The Review summarizes much of particle physics and cosmology. Using data from previous editions, plus 3,200 new measurements from 903 papers, we list, evaluate, and average measured properties of gauge bosons and the recently discovered Higgs boson, leptons, quarks, mesons, and baryons. We summarize searches for hypothetical particles such as supersymmetric particles, heavy bosons, axions, dark photons, etc. Particle properties and search limits are listed in Summary Tables. We give numerous tables, figures, formulae, and reviews of topics such as Higgs Boson Physics, Supersymmetry, Grand Unified Theories, Neutrino Mixing, Dark Energy, Dark Matter, Cosmology, Particle Detectors, Colliders, Probability and Statistics. Most of the 118 reviews are updated, including many that are heavily revised. The Review is divided into two volumes. Volume 1 includes the Summary Tables and 96 review articles. Volume 2 consists of the Particle Listings and contains also 22 reviews that address specific aspects of the data presented in the Listings. The complete Review (both volumes) is published online on the website of the Particle Data Group ( pdg.lbl.gov ) and in a journal. Volume 1 is available in print as the PDG Book. A Particle Physics Booklet with the Summary Tables and essential tables, figures, and equations from selected review articles is available in print, as a web version optimized for use on phones, and as an Android app. The PDG API (Application Programming Interface) provides access to the data published in the Review in machine-readable format.
The Lorentzian type IIB matrix model is a promising candidate for a nonperturbative formulation of superstring theory. In this model, the eigenvalue distribution of the N× N bosonic matrices A_μ (μ= 0 , … , 9) represents an emergent spacetime, which is determined by the dynamics of the model in the large-N limit. Here we perform numerical simulations of the model overcoming the sign problem by the complex Langevin method with the matrix size N up to 128. In order to avoid the singular drift problem due to the Pfaffian, which appears after integrating out the fermionic matrices, we deform the model in a manner inspired by the supersymmetric deformation, which is used to define the “polarized type IIB matrix model” in the Euclidean case. We find that the deformed model exhibits a phase in which (3+1)-dimensional expanding spacetime emerges with both space and time being smooth and real.
We study heavy-hadron semileptonic decays proceeding via b -> c transition, such as B -> D-(*())tau(nu) over bar (tau) and Lambda(b) -> Lambda(c)tau(nu) over bar (tau). In the heavy-quark limit, where the heavy-quark symmetry holds, we provide a fundamental framework for heavy-quark sum rules among these decays based on the spin decomposition picture. The relation holds directly for the squared amplitudes without requiring phase-space integration. We then apply this relation to reproduce the sum rule among B -> D-(*())tau(nu) over bar (tau) and Lambda(b) -> Lambda(c)tau(nu) over bar (tau). Furthermore, we derive new sum rules for Omega(b) -> Omega(()(c)*()) transitions and those involving excited states, such as B -> {D-0*, D-1} and B -> {D-1, D-2*}.
