High-energy electron observations by PPB-BETS flight in Antarctica (2008)
Torii, S., Yamagami, T., Tamura, T., Yoshida, K., Kitamura, H., Anraku, K., ...
We have observed cosmic-ray electrons from 10 GeV to 800 GeV by a long duration balloon flight using Polar Patrol Balloon (PPB) in Antarctica. The observation was carried out for 13 days at an...
Abe, K., Fuke, H., Haino, S., Hams, T., Itazaki, A., Kim, K. C., ...
The BESS-Polar spectrometer had its first successful balloon flight over Antarctica in December 2004. During the 8.5-day long-duration flight, almost 0.9 billion events were recorded and 1,520...
A non-perturbative study of non-commutative U(1) gauge theory (2007)
Nishimura, J., Bietenholz, W., Susaki, Y., Volkholz, J.
We study U(1) gauge theory on a 4d non-commutative torus, where two directions are non-commutative. Monte Carlo simulations are performed after mapping the regularized theory onto a U(N) lattice...
Shikaze, Y., Haino, S., Abe, K., Fuke, H., Hams, T., Kim, K. C., ...
We measured low energy cosmic-ray proton and helium spectra in the kinetic energy range 0.215 - 21.5 GeV/n at different solar activities during a period from 1997 to 2002. The observations were...
Yoshida, K., Ohmori, R., Kobayashi, T., Komori, Y., Sato, Y., Nishimura, J.
We have observed atmospheric gamma rays from 30GeV to 8TeV, using emulsion chambers at balloon altitudes, accumulating the largest total exposure in this energy range to date, SOT ~ 6.66m^2.sr.day....
The Scaling of QED in a Non-Commutative Space-Time (2005)
Volkholz, J., Bietenholz, W., Nishimura, J., Susaki, Y.
We present results of numerical simulations for pure U(1) gauge theory in a non-commutative space. The theory is mapped onto a dimensionally reduced matrix model, which renders its numerical...
Measurements of Atmospheric Antiprotons (2005)
Yamato, K., Abe, K., Fuke, H., Haino, S., Makida, Y., Matsuda, S., ...
We measured atmospheric antiproton spectra in the energy range 0.2 to 3.4 GeV, at sea level and at balloon altitude in the atmospheric depth range 4.5 to 26 g/cm^2. The observed energy spectra,...
Search for Cosmic-Ray Antideuterons (2005)
Fuke, H., Maeno, T., Abe, K., Haino, S., Makida, Y., Matsuda, S., ...
We performed a search for cosmic-ray antideuterons using data collected during four BESS balloon flights from 1997 to 2000. No candidate was found. We derived, for the first time, an upper limit of...
Numerical Results for U(1) Gauge Theory on 2d and 4d Non-Commutative Spaces (2005)
Bietenholz, W., Bigarini, A., Hofheinz, F., Nishimura, J., Susaki, Y., Volkholz, J.
We present non-perturbative results for U(1) gauge theory in spaces, which include a non-commutative plane. In contrast to the commutative space, such gauge theories involve a Yang-Mills term, and...
Intramolecular excimer emission of triply bridged [3.3.n](3,6,9)carbazolophanes (2005)
Benten, H, Ohkita, H, Ito, S, Yamamoto, M, Sakumoto, N, Hori, K, ...
First Simulation Results for the Photon in a Non-Commutative Space (2004)
Bietenholz, W., Hofheinz, F., Nishimura, J., Susaki, Y., Volkholz, J.
We present preliminary simulation results for QED in a non-commutative 4d space-time, which is discretized to a fuzzy lattice. Its numerical treatment becomes feasible after its mapping onto a...
The continuum limit of the non-commutative lambda phi^4 model (2004)
Bietenholz, W., Hofheinz, F., Nishimura, J.
We present a numerical study of the \lambda \phi^{4} model in three Euclidean dimensions, where the two spatial coordinates are non-commutative (NC). We first show the explicit phase diagram of this...
Phase diagram and dispersion relation of the non-commutative \lambda \phi^{4} model in d=3 (2004)
Bietenholz, W., Hofheinz, F., Nishimura, J.
We present a non-perturbative study of the \lambda \phi^{4} model in a three dimensional Euclidean space, where the two spatial coordinates are non-commutative. Our results are obtained from...
Measurements of Primary and Atmospheric Cosmic-Ray Spectra with the BESS-TeV Spectrometer (2004)
Haino, S., Sanuki, T., Abe, K., Anraku, K., Asaoka, Y., Fuke, H., ...
Primary and atmospheric cosmic-ray spectra were precisely measured with the BESS-TeV spectrometer. The spectrometer was upgraded from BESS-98 to achieve seven times higher resolution in momentum...
The Non-Commutative \lambda \phi^{4} Model (2003)
Bietenholz, W., Hofheinz, F., Nishimura, J.
In the recent years, field theory on non-commutative (NC) spaces has attracted a lot of attention. Most literature on this subject deals with perturbation theory, although the latter runs into grave...
Numerical results on the Non-commutative \lambda \phi^4 Model (2003)
Bietenholz, W., Hofheinz, F., Nishimura, J.
The UV/IR mixing in the \lambda \phi^4 model on a non-commutative (NC) space leads to new predictions in perturbation theory, including Hartree-Fock type approximations. Among them there is a changed...
The Factorization Method for Monte Carlo Simulations of Systems With a Complex Action (2003)
Ambjorn, J., Anagnostopoulos, K. N., Nishimura, J., Verbaarschot, J. J. M.
We propose a method for Monte Carlo simulations of systems with a complex action. The method has the advantages of being in principle applicable to any such system and provides a solution to the...
The Most Likely Sources of High Energy Cosmic-Ray Electrons in Supernova Remnants (2003)
Kobayashi, T., Komori, Y., Yoshida, K., Nishimura, J.
Evidences of non-thermal X-ray emission and TeV gamma-rays from the supernova remnants (SNRs) has strengthened the hypothesis that primary Galactic cosmic-ray electrons are accelerated in SNRs. High...
Measurement of Cosmic-Ray Proton and Antiproton Spectra at Mountain Altitude (2003)
Sanuki, T., Fujikawa, M., Matsunaga, H., Abe, K., Anraku, K., Fuke, H., ...
Cosmic-ray proton and antiproton spectra were measured at mountain altitude, 2770 m above sea level. We observed more than 2 x 10^5 protons and 10^2 antiprotons in a kinetic energy range between 0.25...
Measurement of Cosmic-Ray Proton, Antiproton and Muon Spectra at Mountain Altitude (2003)
Sanuki, T., Fujikawa, M., Abe, K., Anraku, K., Fuke, H., Haino, S., ...
Measurement of cosmic-ray proton, antiproton and muon spectra was carried out at mountain altitude. We observed 2 x 10^5 protons and 10^2 antiprotons in a kinetic energy region of 0.25 -- 3.3 GeV....
The Area Law in Matrix Models for Large N Qcd Strings (2003)
K. N. Anagnostopoulos, W. Bietenholz, J. Nishimura
This e#ect motivated in particular the model suggested by Eguchi and Kawai a long time ago. Their point of departure was the standard U(N) lattice gauge theory. Based on the factorization of...
Abe, K., Sanuki, T., Anraku, K., Asaoka, Y., Fuke, H., Haino, S., ...
The cosmic-ray proton, helium, and muon spectra at small atmospheric depths of 4.5 -- 28 g/cm^2 were precisely measured during the slow descending period of the BESS-2001 balloon flight. The...
Non--Commutative Field Theories beyond Perturbation Theory (2002)
Bietenholz, W., Hofheinz, F., Nishimura, J.
We investigate two models in non-commutative (NC) field theory by means of Monte Carlo simulations. Even if we start from the Euclidean lattice formulation, such simulations are only feasible after...
Nishimura, J, Vázquez-Mozo, Miguel Angel
We formulate lattice perturbation theory for gauge theories in noncommutative geometry. We apply it to three-dimensional noncommutative QED and calculate the effective action induced by Dirac...
Nishimura, J., Vazquez-Mozo, M. A.
We formulate lattice perturbation theory for gauge theories in noncommutative geometry. We apply it to three-dimensional noncommutative QED and calculate the effective action induced by Dirac...
Simulating non-commutative field theory (2002)
Bietenholz, W., Hofheinz, F., Nishimura, J.
Non-commutative (NC) field theories can be mapped onto twisted matrix models. This mapping enables their Monte Carlo simulation, where the large N limit of the matrix models describes the continuum...
Ambjorn, J., Anagnostopoulos, K. N., Nishimura, J., Verbaarschot, J. J. M.
Monte Carlo simulations of systems with a complex action are known to be extremely difficult. A new approach to this problem based on a factorization property of distribution functions of observables...
Chern-Simons theory on the lattice (2002)
Bietenholz, W., Nishimura, J., Sodano, P.
We present new proposals for the representation of a Chern-Simons term on the lattice. In the first part, such a term is constructed from the fermion determinant, and in the second part directly from...
Kasahara, K., Mochizuki, E., Torii, S., Tamura, T., Tateyama, N., Yoshida, K., ...
We observed atmospheric gamma-rays around 10 GeV at balloon altitudes (15~25 km) and at a mountain (2770 m a.s.l). The observed results were compared with Monte Carlo calculations to find that an...
Measurements of atmospheric muon spectra at mountain altitude (2002)
Sanuki, T., Fujikawa, M., Abe, K., Anraku, K., Asaoka, Y., Fuke, H., ...
We report new measurements of the atmospheric muons at mountain altitude. The measurement was carried out with the BESS detector at the top of Mt. Norikura, Japan. The altitude is 2,770 m above sea...
Precise Measurements of Atmospheric Muon Fluxes with the BESS Spectrometer (2002)
Motoki, M., Sanuki, T., Orito, S., Abe, K., Anraku, K., Asaoka, Y., ...
The vertical absolute fluxes of atmospheric muons and muon charge ratio have been measured precisely at different geomagnetic locations by using the BESS spectrometer. The observations had been...
A Non-Perturbative Study of Gauge Theory on a Non-Commutative Plane (2002)
Bietenholz, W., Hofheinz, F., Nishimura, J.
We perform a non-perturbative study of pure gauge theory in a two dimensional non-commutative (NC) space. On the lattice, it is equivalent to the twisted Eguchi-Kawai model, which we simulated at N...
The Area Law in Matrix Models for Large N QCD Strings (2001)
Anagnostopoulos, K. N., Bietenholz, W., Nishimura, J.
We study the question whether matrix models obtained in the zero volume limit of 4d Yang-Mills theories can describe large N QCD strings. The matrix model we use is a variant of the Eguchi-Kawai...
On the Quantum Geometry of String Theory (2001)
Ambjorn, J., Anagnostopoulos, K. N., Bietenholz, W., Hofheinz, F., Nishimura, J.
The IKKT or IIB matrix model has been proposed as a non-perturbative definition of type IIB superstring theories. It has the attractive feature that space--time appears dynamically. It is possible...
Asaoka, Y., Shikaze, Y., Abe, K., Anraku, K., Fujikawa, M., Fuke, H., ...
The energy spectra of cosmic-ray low-energy antiprotons and protons have been measured by BESS in 1999 and 2000, during a period covering the solar magnetic field reversal. Based on these...
Anagnostopoulos, K. N., Nishimura, J.
Monte Carlo simulations of a system whose action has an imaginary part are considered to be extremely difficult. We propose a new approach to this `complex-action problem', which utilizes a...
Noncommutative Chiral Gauge Theories on the Lattice with Manifest Star-Gauge Invariance (2001)
Nishimura, J., Vazquez-Mozo, M. A.
We show that noncommutative U(r) gauge theories with a chiral fermion in the adjoint representation can be constructed on the lattice with manifest star-gauge invariance in arbitrary even dimensions....
On the Spontaneous Breakdown of Lorentz Symmetry in Matrix Models of Superstrings (2001)
Ambjorn, J., Anagnostopoulos, K. N., Bietenholz, W., Hofheinz, F., Nishimura, J.
In string or M theories, the spontaneous breaking of 10D or 11D Lorentz symmetry is required to describe our space-time. A direct approach to this issue is provided by the IIB matrix model. We study...
Monte Carlo Studies of the Dimensionally Reduced 4d SU(N) Super Yang-Mills Theory (2001)
Ambjorn, J., Anagnostopoulos, K. N., Bietenholz, W., Hotta, T., Nishimura, J.
We simulate a supersymmetric matrix model obtained from dimensional reduction of 4d SU(N) super Yang-Mills theory. The model is well defined for finite N and it is found that the large N limit...
Ginsparg-Wilson Fermions in Odd Dimensions (2000)
The Ginsparg-Wilson relation, if written in a suitable form, can be used as a condition for lattice Dirac operators of massless fermions also in odd dimensions. The fermion action with such a Dirac...
Noncommutative String Worldsheets from Matrix Models (2000)
Anagnostopoulos, K. N., Nishimura, J., Olesen, P.
We study dynamical effects of introducing noncommutativity on string worldsheets by using a matrix model obtained from the zero-volume limit of four-dimensional SU($N$) Yang-Mills theory. Although...
Simulating Simplified Versions of the IKKT Matrix Model (2000)
Ambjorn, J., Anagnostopoulos, K. N., Bietenholz, W., Hotta, T., Nishimura, J.
We simulate a supersymmetric matrix model obtained from dimensional reduction of 4d SU(N) super Yang-Mills theory (a 4d counter part of the IKKT model or IIB matrix model). The eigenvalue...
CPT anomaly in two-dimensional chiral U(1) gauge theories (2000)
Klinkhamer, F. R., Nishimura, J.
The CPT anomaly, which was first seen in perturbation theory for certain four-dimensional chiral gauge theories, is also present in the exact result for a class of two-dimensional chiral U(1) gauge...
Monte Carlo Studies of the IIB Matrix Model at Large N (2000)
Ambjorn, J., Anagnostopoulos, K. N., Bietenholz, W., Hotta, T., Nishimura, J.
The low-energy effective theory of the IIB matrix model developed by H. Aoki et al. is written down explicitly in terms of bosonic variables only. The effective theory is then studied by Monte Carlo...
Lattice Gauge Fields and Discrete Noncommutative Yang-Mills Theory (2000)
Ambjorn, J., Makeenko, Y. M., Nishimura, J., Szabo, R. J.
We present a lattice formulation of noncommutative Yang-Mills theory in arbitrary even dimensionality. The UV/IR mixing characteristic of noncommutative field theories is demonstrated at a completely...
Spontaneous Breakdown of Lorentz Invariance in IIB Matrix Model (2000)
We study the IIB matrix model, which is conjectured to be a nonperturbative definition of superstring theory, by introducing an integer deformation parameter `nu' which couples to the imaginary part...
Large N Dynamics of Dimensionally Reduced 4D SU(N) Super Yang-Mills Theory (2000)
Ambjorn, J., Anagnostopoulos, K. N., Bietenholz, W., Hotta, T., Nishimura, J.
We perform Monte Carlo simulations of a supersymmetric matrix model, which is obtained by dimensional reduction of 4D SU(N) super Yang-Mills theory. The model can be considered as a four-dimensional...
Precise Measurement of Cosmic-Ray Proton and Helium Spectra with the BESS Spectrometer (2000)
Sanuki, T., Motoki, M., Matsumoto, H., Seo, E. S., Wang, J. Z., Abe, K., ...
We report cosmic-ray proton and helium spectra in energy ranges of 1 to 120 GeV and 1 to 54 GeV/nucleon, respectively, measured by a balloon flight of the BESS spectrometer in 1998. The...
Nonperturbative Dynamics of Noncommutative Gauge Theory (2000)
Ambjorn, J., Makeenko, Y. M., Nishimura, J., Szabo, R. J.
We present a nonperturbative lattice formulation of noncommutative Yang-Mills theories in arbitrary even dimension. We show that lattice regularization of a noncommutative field theory requires...
Finite N Matrix Models of Noncommutative Gauge Theory (1999)
Ambjorn, J., Makeenko, Y. M., Nishimura, J., Szabo, R. J.
We describe a unitary matrix model which is constructed from discrete analogs of the usual projective modules over the noncommutative torus and use it to construct a lattice version of noncommutative...
Precision Measurement of Cosmic-Ray Antiproton Spectrum (1999)
Orito, S., Maeno, T., Matsunaga, H., Abe, K., Anraku, K., Asaoka, Y., ...
The energy spectrum of cosmic-ray antiprotons has been measured in the range 0.18 to 3.56 GeV, based on 458 antiprotons collected by BESS in recent solar-minimum period. We have detected for the...
Measurement of TeV electrons on ISS/JEM (1999)
Torii, S, Tateyama, N, Tamura, T, Ouchi, T, Kashiwagi, K, Yoshida, K, ...
Progress in search for cosmic-ray anti-particles by BESS spectrometer (1998)
Yamamoto, A, Orito, S, Ormes, J F, Yoshida, T, Yoshimura, K, Abe, K, ...
Measurement of Low-Energy Cosmic-Ray Antiprotons at Solar Minimum (1998)
Matsunaga, H., Orito, S., Matsumoto, H., Yoshimura, K., Moiseev, A., Anraku, K., ...
The absolute fluxes of the cosmic-ray antiprotons at solar minimum are measured in the energy range 0.18 to 1.4 GeV, based on 43 events unambiguously detected in BESS '95 data. The resultant energy...
Dynamical Properties of Large N Reduced Model of Yang-Mills Theory (1998)
Hotta, T., Nishimura, J., Tsuchiya, A.
We study the large N reduced model of D-dimensional Yang-Mills theory with special attention to the dynamical aspects related to the eigenvalues of the NxN matrices, which correspond to the...
Single massless Majorana fermion in the domain-wall formalism (1997)
Hotta, T., Izubuchi, T., Nishimura, J.
We study the domain-wall formalism with additional Majorana mass term for the unwanted zero mode, which has recently been proposed for lattice construction of 4D N=1 super Yang-Mills theory without...
A New Limit on the Flux of Cosmic Antihelium (1997)
Saeki, T, Anraku, K, Orito, S, Ormes, J F, Imori, M, Kimbell, B L, ...
A very sensitive search for cosmic-ray antihelium was performed using data obtained from three scientific flights of BESS magnetic rigidity spectrometer. We have not observed any antihelium; this...
A New Limit on the Flux of Cosmic Antihelium (1997)
Saeki, T., Anraku, K., Orito, S., Ormes, J., Imori, M., Kimbell, B., ...
A very sensitive search for cosmic-ray antihelium was performed using data obtained from three scientific flights of BESS magnetic rigidity spectrometer. We have not observed any antihelium; this...
A new phase structure in three-dimensional dynamical triangulation model (1997)
Hotta, T., Izubuchi, T., Nishimura, J.
We investigate a new phase structure of the three-dimensional dynamical triangulation model with an additional local term by Monte Carlo simulation. We find that the first order phase transition...
Massless Majorana fermion on the domain wall (1997)
Hotta, T., Izubuchi, T., Nishimura, J.
We study the domain-wall formalism with additional Majorana mass term for the unwanted zero mode, which has recently been proposed for lattice construction of 4D N=1 super Yang-Mills theory without...
Singular Vertices in the Strong Coupling Phase of Four-Dimensional Simplicial Gravity (1997)
Hotta, T., Izubuchi, T., Nishimura, J.
We study four-dimensional simplicial gravity through numerical simulation with special attention to the existence of singular vertices, in the strong coupling phase, that are shared by abnormally...
The Detection of TeV Gamma Rays from Crab using the Telescope Array Prototype (1997)
Aiso, S., Chikawa, M., Hayashi, Y., Hayashida, N., Hibino, K., Hirasawa, H., ...
The Telescope Array prototype detectors were installed at Akeno Observatory and at the Utah Fly's Eye site. Using these detectors, we have observed the Crab Nebula and AGN's since the end of 1995....
Search for antihelium of cosmic origin (1996)
Anraku, K, Golden, R L, Imori, M, Inaba, S, Kimbell, B L, Kimura, N, ...
Singular Vertices in the Strong Coupling Phase of Four--Dimensional Simplicial Gravity (1995)
Hotta, T., Izubuchi, T., Nishimura, J.
We study four--dimensional simplicial gravity through numerical simulation with special attention to the existence of singular vertices, in the strong coupling phase, that are shared by abnormally...
Operator Product Expansion in Two-Dimensional Quantum Gravity (1995)
Aoki, H., Kawai, H., Nishimura, J., Tsuchiya, A.
We consider correlation functions of operators and the operator product expansion in two-dimensional quantum gravity. First we introduce correlation functions with geodesic distances between...
Observation of cosmic-ray antiprotons at energies below 500 MeV (1995)
Yoshimura, K, Orito, S, Ueda, I, Anraku, K, Golden, R L, Imori, M, ...
Balloon-borne experiment with a superconducting solenoidal magnet spectrometer (1994)
Anraku, K, Golden, R L, Haga, T, Imori, M, Inaba, S, Kimbell, B L, ...
The Effect of Dynamical Gauge Field on the Chiral Fermion on a boundary (1994)
Aoki, H., Iso, S., Nishimura, J., Oshikawa, M.
We study the effect of dynamical gauge field on the Kaplan's chiral fermion on a boundary in the strong gauge coupling limit in the extra dimension. To all orders of the hopping parameter expansion,...