Showing papers by "Masaharu Nomachi published in 2008"
Posted Content•
TL;DR: In this article, a detailed study of the expected performance of the ATLAS detector is presented, together with the reconstruction of tracks, leptons, photons, missing energy and jets, along with the performance of b-tagging and the trigger.
Abstract: A detailed study is presented of the expected performance of the ATLAS detector. The reconstruction of tracks, leptons, photons, missing energy and jets is investigated, together with the performance of b-tagging and the trigger. The physics potential for a variety of interesting physics processes, within the Standard Model and beyond, is examined. The study comprises a series of notes based on simulations of the detector and physics processes, with particular emphasis given to the data expected from the first years of operation of the LHC at CERN.
1,160 citations
University of New Mexico1, Brookhaven National Laboratory2, Indian Institute of Technology Guwahati3, TRIUMF4, University of British Columbia5, Tsinghua University6, Aristotle University of Thessaloniki7, Stony Brook University8, Fermilab9, Kyoto University10, University of Alberta11, University of Fukui12, Osaka University13, National Defense Academy of Japan14
TL;DR: Three events for the decay K+-->pi+nounu have been observed in the pion momentum region below the K+>pi+pi0 peak, 140 pi+ nunu) = (1.73(-1.05)+1.15) x 10(-10) consistent with the standard model prediction as discussed by the authors.
Abstract: Three events for the decay K+-->pi+ nunu have been observed in the pion momentum region below the K+-->pi+pi0 peak, 140 pi+ nunu) = (1.73(-1.05)+1.15) x 10(-10) consistent with the standard model prediction.
198 citations
Brookhaven National Laboratory1, TRIUMF2, Osaka University3, Princeton University4, University of New Mexico5, University of Delhi6, University of British Columbia7, Tsinghua University8, Aristotle University of Thessaloniki9, Stony Brook University10, Fermilab11, Kyoto University12, University of Tokyo13, Hiroshima University14, University of Alberta15, University of Fukui16, National Defense Academy of Japan17
TL;DR: Anisimovsky et al. as mentioned in this paper used a blind analysis technique to yield one candidate event with an estimated background of 0.30 {+-} 0.03 events.
Abstract: Experiment E949 at Brookhaven National Laboratory studied the rare decay K{sup +}-->pi{sup +} nu{ovr {nu}} and other processes with an exposure of 1.77 x 10{sup 12} k{sup +}'s. The data were analyzed using a blind analysis technique yielding one candidate event with an estimated background of 0.30 {+-} 0.03 events. Combining this result with the observation of two candidate events by the predecessor experiment E787 gave the branching ratio B(K{sup +}-->pi{sup +} nu{ovr {nu}}) = (1.47{sub -0.89}{sup +1.30}) x 10{sup -10}, consistent with the standard model prediction of (0.74 {+-} 0.20) x 10{sup -10}. This is a more detailed report of results previously published [V.V. Anisimovsky et al., Phys. Rev. Lett. 93, 031801 (2004)].
86 citations
Journal Article•
TL;DR: In this paper, three events for the decay K + → π + vv have been observed in the pion momentum region below the K + 0 π+ π 0 peak, with an estimated background of 0.93 ± 0.17(stat.) + 0.32 0.24 (syst.) events.
Abstract: Three events for the decay K + → π + vv have been observed in the pion momentum region below the K + → π + π 0 peak, 140 < P π < 199 MeV/c, with an estimated background of 0.93 ± 0.17(stat.) +0.32 0.24 (syst.) events. Combining this observation with previously reported results yields a branching ratio of B(K + → π + vv) = (1.73 +1-15 -1.05 ) X 10 -10 consistent with the standard model prediction.
50 citations
Pusan National University1, Saga University2, Joint Institute for Nuclear Research3, National Taiwan University4, Arizona State University5, Graduate University for Advanced Studies6, Osaka University7, Yamagata University8, University of Chicago9, National Defense Academy of Japan10, Kyoto University11, Francisk Skorina Gomel State University12
TL;DR: In this paper, an upper limit on the branching ratio for the decay at the KEK 12-GeV proton synchrotron was set to be 6.7x10{sup -8} at the 90% confidence level.
Abstract: We performed a search for the K{sub L}{sup 0}{yields}{pi}{sup 0}{nu}{nu} decay at the KEK 12-GeV proton synchrotron. No candidate events were observed. An upper limit on the branching ratio for the decay was set to be 6.7x10{sup -8} at the 90% confidence level.
30 citations
Academia Sinica1, Osaka University2, Kyoto University3, Pusan National University4, Konan University5, Japan Atomic Energy Agency6, Nagoya University7, Seoul National University8, Ohio University9, Tohoku University10, Yamagata University11, Chiba University12, National Kaohsiung Normal University13, Wakayama Medical University14, University of Miyazaki15, National Defense Academy of Japan16, Tokyo Institute of Technology17, University of Saskatchewan18, University of Minnesota19, Michigan State University20
TL;DR: Differential cross sections and decay asymmetries for coherent ϕ-meson photoproduction from deuterons were measured for the first time at forward angles using linearly polarized photons at E γ = 1.5 − 2.4 GeV.
26 citations
Los Alamos National Laboratory1, Pacific Northwest National Laboratory2, University of North Carolina at Chapel Hill3, Lawrence Berkeley National Laboratory4, University of Washington5, University of South Carolina6, North Carolina State University7, University of Chicago8, Oak Ridge National Laboratory9, Joint Institute for Nuclear Research10, University of Tennessee11, Osaka University12, Duke University13, University of Alberta14, Black Hills State University15, University of South Dakota16, Queen's University17
TL;DR: The MAJORANA Collaboration as mentioned in this paper uses the well-established technique of searching for neutrinoless double-beta decay in high purity Ge-diode radiation detectors that play both roles of source and detector.
Abstract: Neutrinoless double-beta decay searches play a major role in determining the nature of neutrinos, the existence of a lepton violating process, and the effective Majorana neutrino mass. The MAJORANA Collaboration proposes to assemble an array of HPGe detectors to search for neutrinoless double-beta decay in 76Ge. Our proposed method uses the well-established technique of searching for neutrinoless double-beta decay in high purity Ge-diode radiation detectors that play both roles of source and detector. The technique is augmented with recent improvements in signal processing and detector design, and advances in controlling intrinsic and external backgrounds. Initially, MAJORANA aims to construct a prototype module containing 60 kg of Ge detectors to demonstrate the potential of a future 1-tonne experiment. The design and potential reach of this prototype Demonstrator module will be presented. This paper will also discuss detector optimization and low-background requirements, such as material purity, background rejection, and identification of rare backgrounds required to reach the sensitivity goals of the MAJORANA experiment.
19 citations
Osaka University1, National Institute of Radiological Sciences2, Czech Technical University in Prague3, University of Washington4, Los Alamos National Laboratory5, University of North Carolina at Chapel Hill6, Charles University in Prague7, University of Tokushima8, International Christian University9, Hiroshima University10, Joint Institute for Nuclear Research11, Tohoku University12
TL;DR: The MOON detector as discussed by the authors is a super ensemble of multi-layer modules, each being composed by PL scintillator plates and position-sensitive detector planes with good overall energy resolution of σ ≈ 2% at the Q ≥ 3 MeV.
Abstract: The MOON (Majorana/Mo Observatory Of Neutrinos) project aims at studies of the Majorana nature of the neutrino (ν) and the ν-mass spectrum by spectroscopic experiments of neutrino-less double beta decays (0νββ) with the ν-mass sensitivity of 〈m
〉 = 100−30 meV. The solid scintillator option of the MOON detector is a super ensemble of multi-layer modules, each being composed by PL scintillator plates and position-sensitive detector planes with good overall energy resolution of σ ≈ 2% at the Q
ββ
≈ 3 MeV. Thin ββ source films are interleaved between the detector planes. High localization of the two β tracks enables one to select true signals and reject BG ones. The multi-layer structure of the detector makes it realistic to build a compact ton-scale detector. MOON with detector ≠ ββ source is used for studying 0νββ decays from 100Mo, 82Se and other ββ isotopes with large Q
ββ
. Real-time exclusive measurements of low energy solar neutrinos can be made by observing inverse β rays from solar-ν captures of 100Mo in delayed coincidence with the subsequent β decay of 100Tc.
18 citations
Osaka University1, University of Washington2, National Institute of Radiological Sciences3, Czech Technical University in Prague4, Los Alamos National Laboratory5, University of North Carolina at Chapel Hill6, Charles University in Prague7, University of Tokushima8, International Christian University9, Hiroshima University10, Joint Institute for Nuclear Research11, Tohoku University12
TL;DR: In this article, the performance of the MOON detector for a next-generation neutrino-less double-beta decay experiment was evaluated by means of the Monte Carlo method.
Abstract: The performance of the MOON detector for a next-generation neutrino-less double-beta decay experiment was evaluated by means of the Monte Carlo method. The MOON detector was found to be a feasible solution for the future experiment to search for the Majorana neutrino mass in the range of 100-30 meV.
7 citations
TL;DR: In this article, the authors investigated the energy resolution of a plastic scintillation detector in terms of ldquocomponentsrdquo in the MeV-electron region.
Abstract: Many experiments on neutrinoless double beta decays have been proposed recently for determining the effective mass of neutrinos. Some of them use a plastic scintillator for measuring the beta-ray energy. Achieving a high energy resolution is critical for neutrinoless double beta decay experiments (e.g., MOON and superNEMO). The motivation of this study is to investigate the energy resolution of a plastic scintillation detector in terms of ldquocomponentsrdquo in the MeV-electron region. It is known that the total energy resolution of a plastic scintillation detector for a monoenergetic spectrum consists of two components: statistical and intrinsic energy resolution. In this paper, these two components were investigated for electrons. Experiments on protons were also performed for the purpose of comparison. Three additional experiments were performed to determine (1) the uniformity of the plastic scintillator materials by scanning a 2.8-MeV proton microbeam, (2) the energy spread of electrons and protons, and (3) the effect of the electron-beam size on the set-up. These additional experiments were performed to ensure that these factors did not affect measurements of the two above-mentioned components.
07 Nov 2008
TL;DR: In this article, three events for the decay K+->pi(+)nu have been observed in the pion momentum region below the K++pi(+pi) peak, 140 pi(+nu nu)=(1.73(-1.05)(+1.15))x10(-10) consistent with the standard model prediction.
Abstract: Three events for the decay K+->pi(+)nu have been observed in the pion momentum region below the K+->pi(+)pi(0) peak, 140 pi(+)nu nu)=(1.73(-1.05)(+1.15))x10(-10) consistent with the standard model prediction.
TL;DR: A trigger logic is introduced which can handle double-pulse events due to high count rate in future X-ray missions and several application on the ground experiments in a digital processing system for a TES microcalorimeter array based on “SpaceWire” interface.
Abstract: A digital processing system for a TES microcalorimeter array is being developed based on “SpaceWire” interface. In this system, we introduced a trigger logic which can handle double-pulse events due to high count rate in future X-ray missions and several application on the ground experiments. The detailed design and performance of this system is described.
Journal Article•
TL;DR: In this article, the angular variation of the relative momentum of the final protons was investigated and it was shown that this is primarily an effect of the interference of pion $s$ and $p$ waves and this interference can also explain the momentum dependence.
Abstract: The differential cross section and analyzing power ${A}_{y}$ of the $\stackrel{\ensuremath{\rightarrow}}{p}p\ensuremath{\rightarrow}\mathit{pp}{\ensuremath{\pi}}^{0}$ reaction have been measured at RCNP in coplanar geometry at a beam energy of 390 MeV and the dependence on both the pion emission angle and the relative momentum of the final protons has been extracted. The angular variation of ${A}_{y}$ for the large values of the relative momentum studied here shows that this is primarily an effect of the interference of pion $s$ and $p$ waves and this interference can also explain the momentum dependence. Within the framework of a very simple model, these results would suggest that the pion-production operator has a significant long-range component.
01 Jul 2008
TL;DR: In this paper, the energy resolution of ultra thin and large area NaI(T1) scintillator has been developed and the estimated sensitivity for spin-dependent excitation of 127I was discussed.
Abstract: Highly segmented inorganic crystal has been shown to have good performance for dark matter search. The energy resolution of ultra thin and large area NaI(T1) scintillator has been developed. The estimated sensitivity for spin-dependent excitation of 127I was discussed. The recent status of low background measurement at Oto Cosmo Observatory is reported