arXiv subjects

I. Nakamura

Publications and source records attributed to I. Nakamura.

24 records · Page 2Linked to original sources

arXiv2008

Comprehensive Analysis of Neutrinos in SK part 3 -- L/E Analysis for Single Ring Muon Events II --

Following the L_nu/E_nu analysis in the preceding paper of the Fully Contained Muon Events resulting from the quasi-elastic scattering obtained from our numerical computer experiment. In the present paper, we carry out the analyses of L_nu/E_mu, L_mu/E_nu and L_mu/E_mu among four possible combinations of L and E. As the result of it, we show that we can not find the characteristis of maximum oscillation for neutrino oscillation among two of three, L_mu/E_mu and L_mu/E_nu. Only the L_nu/E_mu distribution can show something like maximum oscillation, however it cannot be detected owing to the neutral character of L_nu. It is concluded that the Super-Kamiokande Experiment could not have found the existence of the maximum oscillation for neutrino oscillation.

hep-ex↗

arXiv2008

Comprehensive Analysis of Neutrinos in SK part I --Directions of the Incident Neutrinos and the Produced Leptons--

Super-Kamiokande collaboration assumes that the direction of every observed lepton coincides with the incoming direction of the incident neutrino, which is the fundamental basement throughout all their analysis on neutrino oscillation. We examine whether this assumption to explain the experimental results on neutrino oscillation is theoretically acceptable. Treating every physical process concerned stochastically, we have examined if this assumption just cited is acceptable. As the result of it, we have shown that this assumption does not hold even if statistically.

hep-ex↗

arXiv2007

The Reliability on the Direction of the Incident Neutrino for the Fully Contained Events and Partially Contained Events due to QEL in the Super-Kamiokande

In the SK analysis of the neutrino events for [Fully Contained Events] and [Partially Contained Events] on their zenith angle distribution, it is assumed that the zenith angle of the incident neutrino is the same as that of the detected charged lepton. In the present paper, we examine the validity of [the SK assumption on the direction] of the incident neutrinos. Concretely speaking, we analyze muon-like events due to QEL. For the purpose, we develop [Time Sequential Monte Carlo Simulation] to extract the conclusion on the validity of the SK assumption. In our [Time Sequential Simulation], we simulate every physical process concerned as exactly as possible without any approximation. From the comparison between the zenith angle distributon of the emitted muons under [the SK assumption on the direction] and the corresponding one obtained under our [Time Sequential Simulation], it is concluded that the measurement of the direction of the incident neutrino for the neutrino events occurring inside the detector in the SK analysis turns out to be unreliable, which holds irrespective of the existence and/or non-existence of the neutrino oscillation.

hep-ex↗

arXiv2002

Linear $Σ$ Model in the Gaussian Functional Approximation

We apply a self-consistent relativistic mean-field variational ``Gaussian functional'' (or Hartree) approximation to the linear $σ$ model with spontaneously and explicitly broken chiral O(4) symmetry. We set up the self-consistency, or ``gap'' and the Bethe-Salpeter equations. We check and confirm the chiral Ward-Takahashi identities, among them the Nambu-Goldstone theorem and the (partial) axial current conservation [CAC], both in and away from the chiral limit. With explicit chiral symmetry breaking we confirm the Dashen relation for the pion mass and partial CAC. We solve numerically the gap and Bethe-Salpeter equations, discuss the solutions' properties and the particle content of the theory.

hep-th↗

arXiv2001

Search for the Standard Model Higgs Boson in OPAL

A search for the Standard Model Higgs boson with the OPAL detector at LEP was reported. The analysis was based on the full data sample collected at center-of-mass energies of 192-209 GeV in 1999 and 2000, corresponding to an integrated luminosity of approximately 426 /pb. The data shows an excess in a range of 95-120 GeV. The data slightly favour the hypothesis that a signal is present, but also that the data are consistent with the background hypothesis. A lower bound of 109.7 GeV is obtained on the Higgs boson mass at the 95% confidence level.

hep-ex↗

arXiv1995

Bi-layer Heisenberg model studied by the Schwinger-boson Gutzwiller-projection method

A two-dimensional bi-layer, square lattice Heisenberg model with different intraplane($J_{\parallel}$) and interplane($J_{\perp}$) couplings is investigated. The model is first solved in the Schwinger boson mean-field approximation. %It is shown that order-disorder transition occurs as the interplane Coupling %is increased. The critical ratio is $J_{\perp/\p=4.48J$ Then the solution is Gutzwiller projected to satisfy the local constraint that there should be only one boson at each site. For these wave functions, we perform variational Monte Carlo simulation up to $24 \times 24 \times 2$ sites. It is shown that the Néel order is destroyed as the interplane coupling is increased. The obtained critical value, $J_{\perp}/J_{\parallel}=3.51$, is smaller than that by the mean-field theory. Excitation spectrum is calculated by a single mode approximation. It is shown that energy gap develops once the Néel order is destroyed.

cond-mat↗