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Thank you for your interest in attending Symposium of the US-Japan Science and Technology Cooperation Program 2025. This symposium will be held in Sapporo, Japan between May 12th and 14th, 2025.
The U.S.-Japan Cooperation Program in High Energy Physics was started from 1979 to strengthen cooperative relations between the U.S. and Japan in research and development in the fields of high energy physics.
Today, this program is implemented under "the Agreement between the Government of Japan and the Government of the United States of America on Cooperation in Research and Development in Science and Technology" signed on June 20, 1988, "the Implementing Arrangement between the Department of Energy of the United States of America and the Ministry of Education, Culture, Sports, Science and Technology of Japan Concerning Cooperation in Research and Development in Energy and Related Fields" signed on April 30, 2013, and "the Project Arrangement under the Implementing Arrangement between the Department of Energy of the United States of America and the Ministry of Education, Culture, Sports, Science and Technology of Japan Concerning Cooperation in Research and Development in Energy and Related Field Concerning High Energy Physics" signed on October 6, 2015.
It may be difficult to make a resevation in Sapporo, especially for the night of May 11th, just before this symposium is held. Early accommodation booking is recommended.
TBA
Currently, the only experimentally validated measurement of Beyond Standard Model physics is neutrino oscillation; a phenomenon whereby neutrinos can oscillate between their three flavours. The T2K (Tokai to Kamioka) experiment is a long-baseline neutrino oscillation experiment with the goal of making precise measurements of the free parameters of the Pontecorvo-Maki-Nakagawa-Sakata (PMNS) matrix, which describes the mismatch between neututrino weak and mass eigenstates as a unitary rotation matrix. The Super Fine Grain Detector (SuperFGD) is an upgraded component of the T2K experiment introduced to improve upon the reconstruction capabilities of its predecessor due to a finer granularity, improved timing resolution, increased efficiency and increased target mass. Analyses of the systematic uncertainties, data quality, and maintenance of the SuperFGD have been paramount in facilitating better understanding of neutrino beam, cosmic, and LED data; allowing for crucial improvements towards the understanding of neutrino oscillation parameters using analysis methods developed for the SuperFGD. Furthermore, improvements to the understanding of neutrons from antineutrino Charged-Current-Quasi-Elastic interactions serve to greatly improve our understanding of antineutrino energy reconstruction, which is pivotal to the overall goal of understanding neutrino oscillations.
TBA
Conventional superconducting magnets for HEP research are made of low Tc superconductors (LTSs) such as multifilament Nb-Ti composite wires. High Tc superconductors (HTSs) such as REBCO coated conductors have been attracting broad interest for applications to magnets for HEP research, because they can generate high magnetic fields that cannot be generated by using LTSs, and they are much more tolerant of high heat load such as radiation heat load due to their high critical temperatures.
However, the wide flat-tape shape of REBCO coated conductors leads to their following shortcomings: limited current carrying capacity, because it is difficult to assemble tapes into cable, unlike LTS round wires; limited bendability (flat-wise bending, limited torsion), which restricts coil shapes; large magnetization and the hysteresis of magnetization: the both affecting field quality and the latter generating large magnetization loss. The Spiral Copper-plated Striated Coated-conductor cable (SCSC cable) is our novel concept of cable, in which copper-plated multifilament coated conductors are wound spirally on a core in multiple layers. It can carry much more current than a single coated conductor, it is bendable in any direction, and its magnetization is small due to its narrow filaments. Kyoto University has been developing SCSC cables supported by JST and has been collaborating with KEK and LBL toward its applications to magnets for HEP research supported by the Japan-US cooperation program for HEP.
In this presentation, we will present the concept and the current status of R&D of SCSC cable as well as future outlook toward its applications to magnets for HEP research.
This work was supported in part by JST-ALCA-Next Program Grant Number JPMJAN24G1 and in part by JSPS KAKENHI Grant Number JP24H00316, Japan.
Cyomodules with 1.3GHz SRF cavity will be used in International Linear Collider (ILC). SRF cavity group at KEK is now manufacturing one ILC type cryomodule in which eight cavities will be installed. Current situation of manufacturing a cryomodule at KEK will be presented.
Neutrino observations from nearby supernova (SN) bursts play a key role in understanding the SN explosion mechanism. However, the neutrino-oxygen interaction in a few tens MeV, which is important for the observation in Super-Kamiokande, is not well measured, and the neutrino information cannot fully be obtained from the precious SN burst. Therefore, a detailed understanding of this reaction is essential to maximizing supernova neutrino observations.
Therefore, a new neutrino cross-section measurement is proposed using the Spallation Neutrino Source (SNS) in Oak Ridge National Laboratory (ORNL). The preparation of this experiment is ongoing with the support of the US-Japan Science and Technology
Cooperation Program in High Energy Physics for JFY2024 and a newly approved Grant-in-Aid.
This poster reports the current situation results of a prototype test in Kamioka, Japan, and prospect to the plan of ORNL measurement.
Recent CMB observations aim at detecting the degree-scale B-mode polarization of Cosmic Microwave Background (CMB) whose origin is primordial gravitational waves.
To suppress systematic uncertainties derived from instruments enough for future better observation sensitivity, optical characteristics of CMB telescopes, such as the beam pattern, need careful calibration that evaluates even very minor nonidealities.
In this study, we propose a new calibration measurement method that employs a feedback-controlled power-tunable artificial source, which enables us to measure the optical characteristics in a high dynamic range (e.g. more than 60 dB) and to identify the very minor nonidealities (e.g. 0.0001% level), even if the telescope has detectors that are very easy to saturate such as Transition Edge Sensors (TES).
This poster presentation reports a proof-of-concept demonstration in a laboratory using a common commercial antenna for general use. We achieved a 60 dB dynamic range in its beam pattern measurement in the proposed method, and confirmed that the measured beam pattern agreed with that in common measurement methods.
Reconstructing particle tracks in future high-luminosity collider experiments is expected to be challenging. AC-LGAD is one of the candidates to solve the problem using excellent spatial and timing resolution.
In multi-channel readouts, low-power consumption pre-amplifier and digital circuit are required because the number of readout circuit increases with the number of AC-LGADs channels. The timing resolution of AC-LGADs is affected by electronic noise. Therefore, developing a low-noise readout ASIC for multi-channel readout of AC-LGADs is crucial to further improve the timing resolution.
Si-Ge (Silicon-Germanium) based ASICs are characterized by low-power consumption, low-noise and high-speed operation. So, I will present the performance evaluation of Si-Ge based ASICs using signals from AC-LGADs, in response to infrared pulsed laser and β-source.
A Low Gain Avalanche Diode (LGAD) sensor is developed as a semiconductor tracking detector with precise time resolution. In the application of the LGAD detector to high energy and high intensity of hadron collider experiments, the device must have radiation tolerance to both total ionization dose (TID) and non-ionization energy loss (NIEL).
In particular, since LGAD has a p+ implantation layer as an amplification layer, there is a unique problem that radiation damage reduces the number of acceptors in the amplification layer and the amplification gain is reduced.
I will present about the improvement of radiation tolerance with newly prototyped sensors such as different oxygen and inactive boron concentration. The future plan of radiation tolerance developments is also presented.
We present the design and experimental evaluation of two racetrack coils: one is wound using a Spiral Copper-plated Striated Coated-conductor (SCSC) cable developed at Kyoto University, and the other using a reference CORC®-like cable using monofilament coated conductors. In SCSC cable, the striated REBCO tapes are plated with copper and, then, wound spirally on a round core, in order to mitigate magnetization effectively while maintaining its quench stability.
This work details the coil design, termination strategies, and electromagnetic simulations. In the initial phase, using short samples, we assess the impact of epoxy impregnation on critical current degradation and thermal cycling effects. We then present the construction process in fabricating the HTS racetrack coil with epoxy filler, highlighting key design considerations and challenges. Finally, we characterize the coil’s V-I behavior and compare transport AC losses between two coils wound using the SCSC cable and the reference CORC®-like cable under triangular time-varying currents with varying time constants.
This work was supported in part by JST-ALCA-Next Program JPMJAN24G1 and in part by Japan-U.S. Science and Technology Cooperation Program in High Energy Physics.
Ultra-fine A15 composite wires with a diameter of 0.03–0.05 mm are being developed by National Institute for Materials Science (NIMS). Since the bending strain is approximately proportional to the wire diameter, a cable composed of fine wires can be bent to a smaller bending diameter without a degradation of critical current (Ic). Thus, react-and-wind A15 cables are expected to be realized. In this study, the mechanical properties of bronze-processed Nb3Sn wires with a diameter of 0.05 mm were evaluated by using a technique of single fiber tensile test. Basic mechanical parameters such as 0.2% proof strength and fracture strength were successfully evaluated from stress–strain curves. Young’s modulus of such a fine wire was determined from unloading and reloading slopes of a load–stroke curve for the specimens with different gauge lengths. Fracture strain was estimated without using extensometers and strain gauges by correcting for machine deformation. A tensile test was conducted for a twisted cable composed of nineteen 0.05 mm-thick wires at room temperature. The stress tolerance of the single wire and twisted cable was assessed by measuring Ic at 4.2 K after applying various uniaxial tensile loads at room temperature. Through these experiments, we found that the tensile stress limit of Ic of the twisted cable can be predicted from that of the single wire.
Small anisotropies in the Cosmic Microwave Background (CMB) should contain information on quantum fluctuations from the cosmic inflation in the early universe. In particular, the linear polarization anisotropy at degree scales is a key measurement to probe the signal of primordial gravitational waves. One of the challenges for ground-based CMB experiments is the mitigation of the instrumental low-frequency noise caused by atmospheric fluctuations. Polarization modulation by a rotating half-wave plate is a promising technique to mitigate this noise.
Traditional Monte Carlo methods for simulating photon propagation in water Cherenkov detectors are computationally expensive and challenging to optimize using calibration data. In this work, we introduce a novel machine learning approach to simulate photon transport using fast surrogate models. We also demonstrate how these models can be efficiently fine-tuned with calibration data to improve accuracy and performance.
An organic olefin-based thermosetting dicyclopentadiene (DCP) resin, C10H12, commercially available in Japan as TELENE® from RIMTEC Corporation, has a viscosity less than one tenth of that of the CTD-101K® epoxy resin. The TELENE® can tolerate larger strains than CTD-101K® and can have a higher heat capacity by mixing it with high heat capacity powders. Using the TELENE® as the impregnation resin is expected to reduce the number of quench training of Nb3Sn magnets. The viscosity, heat capacity, thermal conductivity, and other physical properties of TELENE® with high heat capacity powders were measured in this study. To confirm the irradiation effect of the pure and mixed TELENE®, the gamma-ray irradiation up to 25 MGy was performed at room temperature using a Cobalt-60 source at the Takasaki Advanced Radiation Research Institute, Japan. The flexural properties of the pure and mixed TELENE® were measured before and after the gamma-ray irradiation and compared to that of CTD-101K®.
The SuperKEKB/Belle II experiment aims to collect high-statistics data of B meson pairs to explore new physics beyond the Standard Model (SM). SuperKEKB, an upgraded version of the KEKB accelerator, has achieved a world-record luminosity of 5.1×1034cm−2s−1 in 2024 but continues to strive for higher luminosities. One of the major obstacles is Sudden Beam Loss (SBL) events, which cause substantial beam losses and damage to the Belle~II detector. To find a hint for addressing SBL challenges, advanced beam diagnostic systems and enhanced beam abort systems have been developed. The diagnostic system aims to accurately pinpoint the start of beam losses, while the upgraded abort system quickly disposes of anomalous beams to minimize damage.
This paper details the development and implementation of these systems, including high-speed loss monitors, time synchronization with the White Rabbit system, and data acquisition systems. Efforts to understand the mechanisms of SBL events, using acoustic sensors to detect discharges, are also discussed. These measures aim to improve the operational stability and luminosity of SuperKEKB, contributing to the experiment's success.
With neutrino oscillation physics firmly established, neutrino experiments have entered the era of precision measurement with limited budget for systematic uncertainties. One significant source of systematics stems from mis-modeling of detector physics processes, for which accurate and precise detector calibration is critical. A traditional approach in a neutrino experiment calibrates individual physics processes one by one, assuming little dependency among each other and missing the opportunity to minimize discrepancies between data and simulation through joint optimization of all models simultaneously. Furthermore, the analysis requires a separate “calibration” software and the manual effort spans typically a few years after physics data taking starts. These challenges can be addressed by an innovation of differentiable physics modeling. Taking an advantage of powerful gradient-based optimization algorithms which powered the explosive progress of deep learning recently, a differentiable simulator can solve the inverse problems including model parameter (self-)calibration as well as input data reconstruction (i.e. unfolding of the detector effects) directly using real data. Concretely, our application demonstrates the automation of simultaneous optimization of all physics models involved by directly minimizing the discrepancy metrics between data and simulation. This eradicates the need of having a separate software as the simulator can calibrate itself, and reduces both human effort and the time required to completely calibrate the whole detector. In addition, backed by well established analytical physics models, the simulator provide a high quality gradient information and enables a joint optimization of other diferentiable tools such as AI/ML-based data reconstruction and/or differentiable event generators. In this poster, we present the demonstration of a differentiable Liquid Argon Time Projection Chambers and Water Cherenkov detectors including two concrete applications: detector calibration and physics reconstruction through gradient-based optimization.
Precise and accurate Modeling of detector physics processes are keys to minimize the systematic uncertainties for experimental measurements. While detector physics model parameters can be optimized through the detector calibration analyses, the result is only as good as how the model can represent the real physics processes. Missing and incorrect analytical models cannot be addressed by detector calibration. Moreover, calibration of a Liquid Argon Time Projection Chamber, the detector choice of the short and long baseline neutrino experiments in the U.S., takes significant human and computational resources for software development, maintenance, and careful applications over the scale of years. In this project, we have addressed these challenges using SIREN, an implicit neural representation technique. SIREN, as a simulation software, can be optimized by directly minimizing the discrepancies between data and simulation without the need of developing a separate calibration software. As a neural network, SIREN is a universal function approximator and can represent any underlying physics models in real data. By design, unlike vanilla neural networks, SIREN guarantees the derivative and integral of the target physics model accurately. The last point implies that SIREN can be used to estimate the model gradient accurately, and hence it can be chained with other differentiable algorithms to jointly optimize for a broad set of applications, or propagation as well as estimation of model uncertainties. In this poster, we will present our application of SIREN for modeling physics of optical signals in LArTPCs. Furthermore, we will demonstrate its strength of differentiability through two applications including data reconstruction and data-driven optimization of other differentiable tools through joint-optimization techniques.