73 research outputs found
Precise measurement on the binding energy of hypertriton from the nuclear emulsion data using analysis with machine learning
6 pags., 3 figs.A machine learning model has been developed to search for events of production and decay of a hypertriton in nuclear emulsion data, which
is used for measuring the binding energy of the hypertriton at the best precision. The developed model employs an established technique
for object detection and is trained with surrogate images generated by Monte Carlo simulations and image transfer techniques. The first
hypertriton event has already been detected with the developed method only with 10−4 of the total emulsion data. It implies that a sufficient
number of hypertriton events will soon be detected for the precise measurement of the hypertriton binding energy
Observation of Spin-Dependent Charge Symmetry Breaking in Interaction: Gamma-Ray Spectroscopy of He
The energy spacing between the ground-state spin doublet of He(1,0) was determined to be keV, by measuring
rays for the transition with a high efficiency germanium
detector array in coincidence with the He He
reaction at J-PARC. In comparison to the corresponding energy spacing in the
mirror hypernucleus H, the present result clearly indicates the
existence of charge symmetry breaking (CSB) in interaction. It is
also found that the CSB effect is large in the ground state but is by one
order of magnitude smaller in the excited state, demonstrating that the
CSB interaction has spin dependence
Unique approach for precise determination of binding energies of hypernuclei with nuclear emulsion and machine learning
4 pags., 1 tab. -- HYP2022 - 14th International Conference on Hypernuclear and Strange Particle PhysicsHypertriton is the lightest hypernucleus and a benchmark in hypernuclear physics. However, it has recently been suggested that its lifetime
and binding energy values may differ from the established values. To solve
this puzzle, it is necessary to measure both values with a higher precision. For
the precise measurement of the binding energy, we are aiming at developing a
novel technique to measure the hypertriton binding energy with unprecedented
accuracy by combining nuclear emulsion data and machine learning techniques.
The analysis will be based on the J-PARC E07 nuclear emulsion data. Furthermore, a machine-learning model is being developed to identify other single and
double-strangeness hypernucle
Hypernuclear event detection in the nuclear emulsion with Monte Carlo simulation and machine learning
This study developed a novel method for detecting hypernuclear events
recorded in nuclear emulsion sheets using machine learning techniques. The
artificial neural network-based object detection model was trained on surrogate
images created through Monte Carlo simulations and image-style transformations
using generative adversarial networks. The performance of the proposed model
was evaluated using -decay events obtained from the J-PARC E07 emulsion
data. The model achieved approximately twice the detection efficiency of
conventional image processing and reduced the time spent on manual visual
inspection by approximately 1/17. The established method was successfully
applied to the detection of hypernuclear events. This approach is a
state-of-the-art tool for discovering rare events recorded in nuclear emulsion
sheets without any real data for training.Comment: 32 pages, 13 figure
Search For A Ξ Bound State In The 12C(K-,K+)X Reaction At 1.8 Gev/c
The 26th International Nuclear Physics Conference, 11-16 September, 2016, Adelaide, Australia
Measurement of differential cross sections for Σ⁺p elastic scattering in the momentum range 0.44–0.80 GeV/c
クォーク間の「芯」をとらえた --物質が安定して存在できる理由の理解に貢献--. 京都大学プレスリリース. 2022-09-05.We performed a novel Σ⁺+p scattering experiment at the J-PARC Hadron Experimental Facility. Approximately 2400 Σ⁺+p elastic scattering events were identified from 4.9 × 10⁷ tagged Σ⁺+ particles in the Σ⁺+ momentum range 0.44-0.80 GeV/c. The differential cross sections of the Σ⁺+p elastic scattering were derived with much better precision than in previous experiments. The obtained differential cross sections were approximately 2 mb/sr or less, which were not as large as those predicted by the fss2 and FSS models based on the quark cluster model in the short-range region. By performing phase-shift analyses for the obtained differential cross sections, we experimentally derived the phase shifts of the ³S₁ and ¹P₁ channels for the first time. The phase shift of the ³S₁ channel, where a large repulsive core was predicted owing to the Pauli effect between quarks, was evaluated as 20° < |δ₃S₁| < 35°. If the sign of δ₃S₁ is assumed to be negative, the interaction in this channel is moderately repulsive, as the Nijmegen extended-sort-core models predicted
High-resolution search for the pentaquark via a pion-induced reaction at J-PARC
The pentaquark has been searched for via the
reaction with beam momenta of 1.92 and 2.01 GeV/ at J-PARC. A missing mass
resolution of 2 MeV (FWHM) was achieved but no sharp peak structure was
observed. The upper limits on the production cross section averaged over the
scattering angle from 2 to 15 in the laboratory frame were
found to be less than 0.28 b/sr at the 90\% confidence level for both the
1.92- and 2.01-GeV/ data. The systematic uncertainty of the upper limits was
controlled within 10\%. Constraints on the decay width were also
evaluated with a theoretical calculation using effective Lagrangian. The
present result implies that the width should be less than 0.36 and 1.9 MeV for
the spin-parity of and , respectively.Comment: 12 pages, 9 figures; published versio
WASA-FRS experiments in FAIR Phase-0 at GSI
We have developed a new and unique experimental setup integrating the central part of the Wide Angle Shower Apparatus (WASA) into the Fragment Separator (FRS) at GSI. This combination opens up possibilities of new experiments with high-resolution spectroscopy at forward and measurements of light decay particles with nearly full solid-angle acceptance in coincidence. The first series of the WASA-FRS experiments have been successfully carried out in 2022. The developed experimental setup and two physics experiments performed in 2022 including the status of the preliminary data analysis are introduced
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