arXiv subjects

Y. Okumura

Publications and source records attributed to Y. Okumura.

8 recordsLinked to original sources

arXiv2010

A Detailed Study on the Range Fluctuations of $10^{11}$eV to $10^{18}$eV Muons in Water and the Fluctuations of the Cherenkov Lights due to the Accompanied Cascade Showers initiated by Muons

The validity of our Monte Carlo simulation procedure ({\it the integral method}) had been verified by the corresponding analytical procedure of which is quite independent of our method methodologically. Also, the results obtained by our procedure are compared with those obtained by the different Monte Carlo simulation procedure ({\it the differential method}) which have been exclusively utilized by the different authors and the agreement between them are found to be well. By utilizing our Monte Carlo procedures, the validity of which is guaranteed in two different procedures, we investigate not only the fluctuation of high energy muons themselves but also fluctuation of the various quantities related to the energy losses by the muons, which are difficult to obtain by {\it the differential method}. Namely, we obtain fluctuation on energy losses of the muons, fluctuation on Cherenkov lights due to the accompanied cascade showers initiated by the muon and the correlations between them . Finally, we obtain the transition curves for Cherenkov lights in KM3 detector, taking into account of all possible fluctuations in the stochastic processes and point out the difficulty of the reliable estimation of the energy of the muons which are resultants of muon neutrino events in the KM3 detectors.

astro-ph.HE↗

arXiv2010

(Ultra-)High Energy Muon Neutrino Propagation through the Earth and Induced Muon Energy Distribution near the One Cubic Kilometer Detector

We calculate high and (ultra-)high energy upward-going muon neutrino propagation through the Earth and the induced muon energy distribution near the one cubic kilometer detector using the Monte Carlo simulation, due to both charged current interaction and neutral one. The initiated neutrino energies on the surface of the Earth are 1PeV, 1EeV and 1ZeV. The mean free paths of (ultra-)high energy neutrino events generated by the deep inelastic scattering may be comparable with the diameter of the Earth or less than it. Therefore, the induced muon production distribution is influenced by the change of the densities interior to the Earth. Furthermore, in such situation, the contribution from the neutral current neutrino interaction to the induced muon production distribution cannot be neglected. We report several examples of the deep inelastic scattered depth of muon neutrino in the Earth and the induced muon energy distribution near the detector.

astro-ph.HE↗

arXiv2010

Fluctuation of TeV to EeV Energy Muons and Induced Muon Showers in Water

By using the integral method in the muon propagation through water, we calculate the range fluctuation of high and ultra high energy muons. Many authors divide all radiative processes into two parts, namely, the continuous part and radiative part in their Monte Carlo simulation in order to consider the fluctuation in the both ranges and energies of the muons, while we treat all stochastic processes as exactly as possible, without the introduction of the continuous parts in all stochastic processes. The validity of our Monte Carlo method is checked by the corresponding analytical method which is methodologically independent on the Monte Carlo procedure. Accompanied cascade showers are generated by the direct electron pair production, bremsstrahlung and photo-nuclear interaction. These showers are calculated by the exact Monte Carlo Method in one dimensional way. We report survival probabilities, range distributions and examples of individual muon behavior.

astro-ph.HE↗

arXiv2001

Chiral unitary theory: application to nuclear problems

In this talk we briefly describe some basic elements of chiral perturbation theory, $χPT$, and how the implementation of unitarity and other novel elements lead to a better expansion of the $T$ matrix for meson meson and meson baryon interactions. Applications are then done to the $ ππ$ interaction in nuclear matter in the scalar and vector channels, antikaons in nuclei and $K^-$ atoms, and how the $ϕ$ meson properties are changed in a nuclear medium.

nucl-th↗

arXiv2001

Antikaons in nuclei and dense nuclear matter

We present recent progress on the properties of antikaons in nuclei and dense nuclear matter as obtained from two {\bar K}N interaction models: one based on the lowest-order meson-baryon chiral lagrangian and the other derived from a meson-exchange picture.

nucl-th↗

arXiv2000

Chiral Unitary Approach to the Kaon Nucleus Interaction and Kaonic Atoms

We review recent work on various topics related to the modification of kaon properties in nuclei. After a brief exposition of the kaon-nucleon and kaon-nucleus interaction, results from the application to kaonic atoms, renormalization of the f0 and a0 scalar resonances in nuclei and phi decay in the nucleus are shown.

nucl-th↗

arXiv1999

Recent progress on the chiral unitary approach to meson meson and meson baryon interactions

We report on recent progress on the chiral unitary approach, analogous to the effective range expansion in Quantum Mechanics, which is shown to have a much larger convergence radius than ordinary chiral perturbation theory, allowing one to reproduce data for meson meson interaction up to 1.2 GeV. Applications to physical processes so far unsuited for a standard chiral perturbative approach are presented. Results for the extension of these ideas to the meson baryon sector are discussed, together with applications to kaons in a nuclear medium and $K^-$ atoms.

nucl-th↗

arXiv1995

Modified Reconstruction of Standard Model in Non-Commutative Differential Geometry

Sogami recently proposed the new idea to express Higgs particle as a kind of gauge particle by prescribing the generalized covariant derivative with gauge and Higgs fields operating on quark and lepton fields. The field strengths for both the gauge and Higgs fields are defined by the commutators of the covariant derivative by which he could obtain the Yang-Mills Higgs Lagrangian in the standard model. Inspired by Sogami's work, we present a modification of our previous scheme to formulate the spontaneously broken gauge theory in non-commutative geometry on the discrete space; Minkowski space multiplied by two points space by introducing the generation mixing matrix in operation of the generalized derivative on the more fundamental fields a_i(x,y) which compose the gauge and Higgs fields. The standard model is reconstructed according to the modified scheme, which does not yields not only any special relations between the particle masses but also the special restriction on the Higgs potential.

hep-th↗