Publications (43)
Performance of the Fully-equipped Spin Flip Chopper For Neutron Lifetime Experiment at J-PARC
K. Mishima, G. Ichikawa, Y. Fuwa +19
To solve the ''neutron lifetime puzzle,'' where measured neutron lifetimes differ depending on the measurement methods, an experiment with pulsed neutron beam at J-PARC is in progr…
Angular distribution of rays from the p-wave resonance of Sn
J. Koga, S. Takada, S. Endo +14
The neutron energy-dependent angular distribution of rays from reaction was measured with germanium detectors and a pulsed neutron beam. The angular dis…
Improved measurements of neutron lifetime with cold neutron beam at J-PARC
Y. Fuwa, T. Hasegawa, K. Hirota +28
The ``neutron lifetime puzzle'' arises from the discrepancy between neutron lifetime measurements obtained using the beam method, which measures decay products, and the bottle meth…
Cryogenic systems for the TUCAN EDM experiment
Jeffery W. Martin, B. Algohi, D. Anthony +60
The TUCAN (TRIUMF UltraCold Advanced Neutron) Collaboration is completing a new ultracold neutron (UCN) source. The UCN source will deliver UCNs to a neutron electric dipole moment…
Characterization of electroless nickel-phosphorus plating for ultracold-neutron storage
H. Akatsuka, T. Andalib, B. Bell +51
Electroless nickel plating is an established industrial process that provides a robust and relatively low-cost coating suitable for transporting and storing ultracold neutrons (UCN…
Transverse asymmetry of rays from neutron-induced compound states of
T. Yamamoto, T. Okudaira, S. Endo +17
A correlation term in the reaction has been studied utilizing epithermal polarized neutrons and germanium…
Improved determination of thermal cross section of 14N(n,p)14C for the neutron lifetime measurement
R. Kitahara, K. Hirota, S. Ieki +21
In a neutron lifetime measurement at the Japan Proton Accelerator Complex, the neutron lifetime is calculated by the neutron decay rate and the incident neutron flux. The flux is o…
New high-sensitivity searches for neutrons converting into antineutrons and/or sterile neutrons at the European Spallation Source
A. Addazi, K. Anderson, S. Ansell +92
The violation of Baryon Number, , is an essential ingredient for the preferential creation of matter over antimatter needed to account for the observed baryon asymmetr…
Neutron-Antineutron Oscillations: Theoretical Status and Experimental Prospects
D. G. Phillips, W. M. Snow, K. Babu +60
This paper summarizes the relevant theoretical developments, outlines some ideas to improve experimental searches for free neutron-antineutron oscillations, and suggests avenues fo…
First ultracold neutrons produced at TRIUMF
S. Ahmed, E. Altiere, T. Andalib +50
We installed a source for ultracold neutrons at a new, dedicated spallation target at TRIUMF. The source was originally developed in Japan and uses a superfluid-helium converter co…
Experimental Signature of Medium Modifications for rho and omega Mesons in the 12 GeV p + A Reactions
M. Naruki, H. Funahashi, Y. Fukao +23
The invariant mass spectra of e+e- pairs produced in 12-GeV proton-induced nuclear reactions are measured at the KEK Proton-Synchrotron. On the low-mass side of the omega meson pea…
Measurement of nuclear spin relaxation time in lanthanum aluminate for development of polarized lanthanum target
K. Ishizaki, H. Hotta, I. Ide +10
The nuclear spin-lattice relaxation time () of lanthanum and aluminum nuclei in a single crystal of lanthanum aluminate doped with neodymium ions is studied to estimate the fe…
Neutron EDM Experiment with an Advanced Ultracold Neutron Source at TRIUMF
T. Higuchi, B. Algohi, D. Anthony +67
The TRIUMF Ultracold Advanced Neutron (TUCAN) collaboration has been developing a high-intensity ultracold neutron (UCN) source aimed at searching for the neutron electric dipole m…
A Cold/Ultracold Neutron Detector using Fine-grained Nuclear Emulsion with Spatial Resolution less than 100 nm
N. Naganawa, T. Ariga, S. Awano +9
A new type of cold/ultracold neutron detector that can realize a spatial resolution of less than 100 nm was developed using nuclear emulsion. The detector consists of a fine-graine…
Development and application of a He Neutron Spin Filter at J-PARC
T. Okudaira, T. Oku, T. Ino +22
We are developing a neutron polarizer with polarized He gas, referred to as a He spin filter, based on the Spin Exchange Optical Pumping (SEOP) for polarized neutron scatte…
Circular polarization measurement for individual gamma rays in capture reactions with intense pulsed neutrons
S. Endo, R. Abe, H. Fujioka +21
Measurements of circular polarization of -ray emitted from neutron capture reactions provide valuable information for nuclear physics studies. The spin and parity of excited st…
Energy dependent angular distribution of individual -rays in the La(, )La* reaction
T. Okudaira, S. Endo, H. Fujioka +14
Neutron energy-dependent angular distributions were observed for individual -rays from the 0.74 eV p-wave resonance of La+ to several lower excited states of $^{140}…
High sensitivity of a future search for P-odd/T-odd interactions on the 0.75 eV -wave resonance in forward transmission determined using pulsed neutron beam
R. Nakabe, C. J. Auton, S. Endo +27
Neutron transmission experiments can offer a new type of highly sensitive search for time-reversal invariance violating (TRIV) effects in nucleon-nucleon interactions via the same…
Angular distribution of -rays from a neutron-induced -wave resonance of Xe
T. Okudaira, Y. Tani, S. Endo +16
A neutron-energy dependent angular distribution was measured for individual -rays from the 3.2 eV -wave resonance of Xe+, that shows enhanced parity violation owi…
Measurement of rays from LiF tile as an inner wall of a neutron-decay detector
J. Koga, S. Ieki, A. Kimura +12
A neutron lifetime measurement conducted at the Japan Proton Accelerator Research Complex (J-PARC) is counting the number of electrons from neutron decays with a time projection ch…
Nuclear mass number dependence of inclusive production of omega and phi mesons in 12 GeV p + A collisions
T. Tabaru, H. En'yo, R. Muto +23
The inclusive production of omega and phi mesons is studied in the backward region of the interaction of 12 GeV protons with polyethylene, carbon, and copper targets. The mesons ar…
A neutron detector with spatial resolution of submicron using fine-grained nuclear emulsion
N. Naganawa, S. Awano, M. Hino +9
We have been developing a neutron detector with spatial resolution of submicron by loading 6Li into fine-grained nuclear emulsion. By exposure to thermal neutrons, tracks from neut…
Initial results of the TRIUMF ultracold advanced neutron source
B. Algohi, D. Anthony, L. Barrón-Palos +83
We report the first results on ultracold neutron production from a new spallation-driven superfluid He (He-II) source at TRIUMF, which is being prepared for a new, precise meas…
Development of a Modular Current-Mode NaI(Tl) Detector Array for Parity Odd (n,γ) Cross Section Measurements
J. T. Mills, J. G. Otero Munoz, K. Dickerson +26
The Neutron Optics Parity and Time-Reversal Violation Experiment (NOPTREX) Collaboration has developed a modular array of 24 NaI(Tl) detectors to measure parity and time-reversal s…
Angular Distribution of -rays from Neutron-Induced Compound States of La
T. Okudaira, S. Takada, K. Hirota +10
Angular distribution of individual -rays, emitted from a neutron-induced compound nuclear state via radiative capture reaction of La(n,) has been studied as a fun…
Pulsed UCN production using a Doppler shifter at J-PARC
S. Imajo, K. Mishima, M. Kitaguchi +8
We have constructed a Doppler-shifter-type pulsed ultra-cold neutron (UCN) source at the Materials and Life Science Experiment Facility (MLF) of the Japan Proton Accelerator Resear…
Spin dependence in the -wave resonance of
T. Okudaira, R. Nakabe, S. Endo +24
We measured the spin dependence in a neutron-induced -wave resonance by using a polarized epithermal neutron beam and a polarized nuclear target. Our study focuses on the 0.75~e…
Neutron lifetime measurement with pulsed cold neutrons
K. Hirota, G. Ichikawa, S. Ieki +26
The neutron lifetime has been measured by comparing the decay rate with the reaction rate of He nuclei of a pulsed neutron beam from the spallation neutron source at the Japan…
Ultracold Neutron Guide-Coating Facility at U.Winnipeg
T. Hepworth, A. Zahra, B. Algohi +72
We report the construction and commissioning of a new ultracold neutron (UCN) guide-coating facility at the University of Winnipeg. The facility employs pulsed laser deposition (PL…
A New High-Intensity Source for Ultracold Neutrons
K. Abe, S. Ahmed, B. Algohi +77
The TRIUMF UltraCold Advanced Neutron (TUCAN) collaboration has completed a new superthermal source for ultracold neutrons (UCNs) at TRIUMF. It uses neutrons from a spallation targ…
Neutron-Antineutron Oscillations: A Snowmass 2013 White Paper
K. Babu, S. Banerjee, D. V. Baxter +69
This paper summarizes discussions of the theoretical developments and the studies performed by the NNbarX collaboration for the 2013 Snowmass Community Summer Study.
Evidence for in-medium modification of the meson at normal nuclear density
R. Muto, H. En'yo, M. Naruki +23
Invariant mass spectra of e+e- pairs have been measured in 12 GeV p+A reactions to detect possible in-medium modification of vector mesons. Copper and carbon targets are used to st…
Fundamental Nuclear and Particle Physics At Neutron Sources
H. Abele, J. Amaral, W. R. Anthony +121
Fundamental neutron and neutrino physics at neutron sources, combining precision measurements and theory, can probe new physics at energy scales well beyond the highest energies pr…
Improved Measurements of Muonic Helium Ground-State Hyperfine Structure at a Near-Zero Magnetic Field
P. Strasser, S. Fukumura, R. Iwai +9
Muonic helium atom hyperfine structure (HFS) measurements are a sensitive tool to test the three-body atomic system and bound-state quantum electrodynamics theory, and determine fu…
Precise Neutron Lifetime Measurement Using Pulsed Neutron Beams at J-PARC
N. Sumi, K. Hirota, G. Ichikawa +18
A neutron decays into a proton, an electron, and an anti-neutrino through the beta-decay process. The decay lifetime (880 s) is an important parameter in the weak interaction…
Development of time projection chamber for precise neutron lifetime measurement using pulsed cold neutron beams
Y. Arimoto, N. Higashi, Y. Igarashi +24
A new time projection chamber (TPC) was developed for neutron lifetime measurement using a pulsed cold neutron spallation source at the Japan Proton Accelerator Research Complex (J…
A diffuse scattering model of ultracold neutrons on wavy surfaces
S. Imajo, H. Akatsuka, K. Hatanaka +10
Metal tubes plated with nickel-phosphorus are used in many fundamental physics experiments using ultracold neutrons (UCN) because of their ease of fabrication. These tubes are usua…
Transverse asymmetry of individual -rays in the La(, )La reaction
M. Okuizumi, C. J. Auton, S. Endo +21
The enhancement of the parity-violating asymmetry in the vicinity of -wave compound nuclear resonances was observed for a variety of medium-heavy nuclei. The enhanced parity-vio…
Development of a Pixel Detector for Ultra-Cold Neutrons
S. Kawasaki, G. Ichikawa, M. Hino +5
A pixel detector with high spatial resolution and temporal information for ultra-cold neutrons is developed based on a commercial CCD on which a neutron converter is attached. 10B…
Observation of the Spatial Distribution of Gravitationally Bound Quantum States of Ultracold Neutrons and Its Derivation Using the Wigner Function
G. Ichikawa, S. Komamiya, Y. Kamiya +9
Ultracold neutrons (UCNs) can be bound by the potential of terrestrial gravity and a reflecting mirror. The wave function of the bound state has characteristic modulations. We carr…
Nuclear-matter modification of decay widths in the and channels
F. Sakuma, J. Chiba, H. En'yo +23
The invariant mass spectra of are measured in 12 GeV reactions in order to search for the in-medium modification of mesons. The observed …
Measurement of the transverse asymmetry of -rays in the Sn(n,)Sn reaction
S. Endo, T. Okudaira, R. Abe +13
Largely enhanced parity-violating effects observed in compound resonances induced by epithermal neutrons are currently attributed to the mixing of parity-unfavored partial amplitud…
Observation of Meson Modification in Nuclear Matter
K. Ozawa, H. En'yo, H. Funahashi +21
We have measured invariant mass spectra of electron-positron pairs in the target rapidity region of 12GeV p+A reactions. We have observed a significant difference in the mass spect…