A5077639787- Particle Detector Development and Performance
- Dark Matter and Cosmic Phenomena
- Particle physics theoretical and experimental studies
- Neutrino Physics Research
- Radiation Detection and Scintillator Technologies
- Atomic and Subatomic Physics Research
- Muon and positron interactions and applications
- Quantum Chromodynamics and Particle Interactions
- Quantum, superfluid, helium dynamics
- Radiation Effects in Electronics
- AI-based Problem Solving and Planning
- Neural Networks and Applications
- CCD and CMOS Imaging Sensors
- Semantic Web and Ontologies
- Distributed and Parallel Computing Systems
- Machine Learning and Data Classification
- Gene expression and cancer classification
The University of Tokyo
2018-2024
Abstract The MEG II experiment, based at the Paul Scherrer Institut in Switzerland, reports result of a search for decay $$\upmu ^+ \rightarrow {\textrm{e}}^+ \upgamma $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msup> <mml:mi>μ</mml:mi> <mml:mo>+</mml:mo> </mml:msup> <mml:mo>→</mml:mo> <mml:mtext>e</mml:mtext> </mml:mrow> <mml:mi>γ</mml:mi> </mml:math> from data taken first physics run 2021. No excess events over expected background is observed, yielding an...
Abstract The MEG II experiment, located at the Paul Scherrer Institut (PSI) in Switzerland, is successor to which completed data taking 2013. started fully operational 2021, with goal of improving sensitivity $$\upmu ^+ \rightarrow {\textrm{e}}^+ \upgamma $$ <mml:math...
The MEG experiment took data at the Paul Scherrer Institute in years 2009–2013 to test violation of lepton flavor conservation law, which originates from an accidental symmetry that Standard Model elementary particle physics has, and published most stringent limit on charged violating decay μ+→e+γ: BR(μ+→e+γ) <4.2×10−13 90% confidence level. detector has been upgraded order reach a sensitivity 6×10−14. basic principle II is achieve highest possible using full muon beam intensity (7×107...
The MEG II experiment searches for a charged-lepton-flavour-violating μ → eε with the target sensitivity of 6×10− 14 . A liquid xenon calorimeter VUV-sensitive photosensors measures photon position, timing, and energy. This paper concentrates on precise energy reconstruction calorimeter. Since muon beam rate is 3–5 × 10 7 s− 1 , multi-photon elimination analysis performed using waveform techniques such as template fit. As result, background events in range 48–58 MeV were reduced by 34 %....
Abstract We present the first direct search for lepton flavour violating muon decay mediated by a new light particle X, $$\upmu ^+ \rightarrow \mathrm {e}^+\mathrm {X}, {X} \upgamma \ $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msup> <mml:mi>μ</mml:mi> <mml:mo>+</mml:mo> </mml:msup> <mml:mo>→</mml:mo> <mml:mi>e</mml:mi> </mml:mrow> <mml:mi>X</mml:mi> <mml:mo>,</mml:mo> <mml:mi>γ</mml:mi> <mml:mspace /> </mml:math> . This uses dataset resulting from...
The MEG II experiment, based at the Paul Scherrer Institut in Switzerland, reports result of a search for decay $\mu^+\to e^+\gamma$ from data taken first physics run 2021. No excess events over expected background is observed, yielding an upper limit on branching ratio B($\mu^+\to e^+\gamma$) < $7.5 \times 10^{-13}$ (90% C.L.). combination this and obtained by gives $3.1 C.L.), which most stringent to date. A ten-fold larger sample being collected during years 2022-2023, data-taking will...
The MEG experiment represents the state of art in search for Charged Lepton Flavour Violating μ+→e+γ decay. With its first phase operations at Paul Scherrer Institut (PSI), set most stringent upper limit on BR (μ+→e+γ)≤4.2×10−13 90% confidence level, imposing one tightest constraints models predicting LFV-enhancements through new physics beyond Standard Model. An upgrade experiment, II, was designed and it is presently commissioning phase, aiming a sensitivity level 6×10−14. II relies series...
The MEG II experiment, located at the Paul Scherrer Institut (PSI) in Switzerland, is successor to which completed data taking 2013. started fully operational 2021, with goal of improving sensitivity mu+ -> e+ gamma decay down 6e-14 almost an order magnitude better than current limit. In this paper, we describe operation and performance experiment give a new estimate its versus acquisition time.
A new type of resistive plate chamber (RPC) is under development using thin-film electrodes based on diamond-like carbon (DLC). Planned to be put the path high-intensity low-momentum muon beam MEG II experiment, this detector required high-rate capable and ultra-low mass. Using a prototype with 2 cm $\times$ size 0.1 % $X_0$ material budget, performance studies were conducted for MIP detection efficiency, timing resolution high rate capability in beam. In paper, measured presented including...
A novel Resistive Plate Chamber (RPC) was designed with Diamond-Like Carbon (DLC) electrodes and performance studies were carried out for 384$\,\mathrm{\mu m}$ gap configuration a $2\,\mathrm{cm}\times2\,\mathrm{cm}$ prototype. The use of thin films coated DLC enables an ultra-low mass design $< 0.1\%\,X_0$ up to four-layer configuration. At the same time, 42% MIP efficiency, 180 ps timing resolution per layer achieved in measurement performed under $1\,\mathrm{MHz/cm^2}$ non-MIP charged...
The MEG II experiment searches for a charged-lepton-flavour-violating $\mu \to e \gamma$ with the target sensitivity of $6 \times 10^{-14}$. A liquid xenon calorimeter VUV-sensitive photosensors measures photon position, timing, and energy. This paper concentrates on precise energy reconstruction calorimeter. Since muon beam rate is $3\text{-}5 10^{7}~\text{s}^{-1}$, multi-photon elimination analysis performed using waveform techniques such as template fit. As result, background events in...
Reasoning is central to a wide range of intellectual activities, and while the capabilities large language models (LLMs) continue advance, their performance in reasoning tasks remains limited. The processes mechanisms underlying are not yet fully understood, but key elements include path exploration, selection relevant knowledge, multi-step inference. Problems solved through synthesis these components. In this paper, we propose benchmark that focuses on specific aspect ability: direct...
A new type of resistive plate chamber (RPC) is under development using thin-film electrodes based on diamond-like carbon (DLC). Planned to be put the path high-intensity low-momentum muon beam MEG II experiment, this detector required high-rate capable and ultra-low mass. Using a prototype with 2 cm $\times$ size 0.1 % $X_0$ material budget, performance studies were conducted for MIP detection efficiency, timing resolution high rate capability in beam. In paper, measured presented including...
MEG II experiment is an upgrade of to search for charged lepton flavor violating decay muon, $\mu \rightarrow e\gamma$. Target sensitivity $6 \times 10^{-14}$ at 90% C.L., which one order magnitude better than MEG. Liquid xenon detector was used detect $53 \,\mathrm{MeV}$ signal $\gamma$-ray in MEG, and this has been upgraded II. Replacement 216 PMTs on the entrance face with 4092 newly developed VUV-sensitive MPPCs carried out have granularity uniformity scintillation readout. In 2017,...
A new type of resistive plate chamber with thin-film electrodes based on diamond-like carbon is under development for background identification in the MEG II experiment. Installed a low-momentum and high-intensity muon beam, detector required to have extremely low mass high rate capability. single-layer prototype 2 cm $\times$ size was constructed evaluated capability 1 MHz/cm$^2$ muons. For higher scalability size, supply voltage were segmented at pitch by implementing conductive pattern...