150 research outputs found
Search for the pentaquark via the reaction at 1.92 GeV/
The pentaquark baryon was searched for via the
reaction in a missing-mass resolution of 1.4 MeV/(FWHM) at J-PARC.
meson beams were incident on the liquid hydrogen target with the beam momentum
of 1.92 GeV/. No peak structure corresponding to the mass was
observed. The upper limit of the production cross section averaged over the
scattering angle of 2 to 15 in the laboratory frame was
obtained to be 0.26 b/sr in the mass region of 1.511.55 GeV/.The
upper limit of the decay width using the effective Lagrangian
approach was obtained to be 0.72 MeV/ and 3.1 MeV/ for
and , respectively.Comment: 5 pages, 3 figures, 1 tabl
Sympatric Occurrence of Taenia solium, T. saginata, and T. asiatica, Thailand
We confirmed sympatric occurrence of Taenia solium, T. saginata, and T. asiatica in western Thailand. DNA analysis of morphologically identified T. saginata, in a dual infection with T. solium, indicated it was T. asiatica. To our knowledge, this report is the first of T. asiatica and a dual Taenia infection from Thailand
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
Search for the pentaquark at J-PARC
We have been searching for the Θ^+ pentaquark via the π^−p→K^−X reaction at the J-PARC hadron facility. No peak structure was observed in the missing mass spectrum obtained at 1.92 GeV/c beam momentum. The upper limit for the production cross section averaged over the scattering angle from 2° to 15° in the laboratory frame was derived to be 0.26 μb/sr. In order to make a more stringent constraint we have also performed a measurement at 2.0 GeV/c. Present analysis status of this new data is reported
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
Beam and SKS spectrometers at the K1.8 beam line
High-resolution spectrometers for both incident beams and scattered particles have been constructed at the K1.8 beam line of the Hadron Experimental Facility at J-PARC. A point-to-point optics is realized between the entrance and exit of QQDQQ magnets for the beam spectrometer. Fine-pitch wire chamber trackers and hodoscope counters are installed in the beam spectrometer to accept a high rate beam up to 107 Hz. The superconducting kaon spectrometer for scattered particles was transferred from KEK with modifications to the cryogenic system and detectors. A missing-mass resolution of 1.9 ± 0.1 MeV/c2 (FWHM) was achieved for the ∑ peaks of (π±, K+) reactions on a proton target in the first physics run of E19 in 2010
Combined analysis of Belle and Belle II data to determine the CKM angle ϕ3 using B+ → D(K0S h+h−)h+ decays
Erratum to: Combined analysis of Belle and Belle II data to determine the CKM angle ϕ3 using B+ → D(K0Sh+h−)h+ decays
Precise measurement of the lifetime at Belle II
We measure the lifetime of the meson using a data sample of 207
fb collected by the Belle II experiment running at the SuperKEKB
asymmetric-energy collider. The lifetime is determined by fitting the
decay-time distribution of a sample of
decays. Our result is \tau^{}_{D^+_s} = (498.7\pm
1.7\,^{+1.1}_{-0.8}) fs, where the first uncertainty is statistical and the
second is systematic. This result is significantly more precise than previous
measurements.Comment: 7 pages, 4 figures, to be submitted to Physical Review Letter
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