arXiv subjects

T. Teshima

Publications and source records attributed to T. Teshima.

12 recordsLinked to original sources

arXiv2007

ϕ\toπ^0ηγand ϕ\toπ^0π^0γdecays and Mixing Between Low and High Mass Scalar Mesons

Radiative decays ϕ\toηπ^0γand ϕ\toπ^0π^0γare studied assuming that these decays are caused through the intermediate a_0(980)γand f_0(980)γstates, respectively. Fitting the experimental data of the ηπ^0 and π^0π^0 invariant mass spectrum in the decays ϕ\toηπ^0γand π^0π^0γ, it is shown that the processes ϕ\to a_0γand ϕ\to f_0γare dominated by the K^+K^- loop interaction rather than the contact ϕa_0(f_0)γone both for the non-derivative and derivative SPP coupling. The experimental data of Γ[ϕ\to f_0γ]/Γ[ϕ\to a_0γ] predicts that g_{f_0K\bar{K}}/g_{a_0K\bar{K}} \sim 2. Considering the effects of the mixing between low mass scalar qq\bar{q}\bar{q} states and high mass scalar q\bar{q} states to these coupling constants g_{f_0K\bar{K}} and g_{a_0K\bar{K}}, one suggests that the mixing is rather large.

hep-ph↗

arXiv2005

Flavor Mass and Mixing and S_3 Symmetry -- An S_3 Invariant Model Reasonable to All --

We assume that weak bases of flavors (u, c)_{L,R}, (d,s)_{L,R}, (e, μ) _{L,R}, (ν_e, ν_μ)_{L,R} are the S_3 doublet and t_{L,R}, b_{L,R}, τ_{L,R}, {ν_τ}_{L,R} are the S_3 singlet and further there are S_3 doublet Higgs (H_D^1, H_D^2) and S_3 singlet Higgs H_S. We suggest an S_3 invariant Yukawa interaction, in which masses caused from the interaction of S_3 singlet flavors and Higgs is very large and masses caused from interactions of S_3 doublet flavors and Higgs are very small, and the vacuum expectation value <|H_D^1|>_0 is rather small compared to the <|H_D^2|>_0. In this model, we can explain the quark sector mass hierarchy, flavor mixing V_{CKM} and measure of CP violation naturally. The leptonic sector mass hierarchy and flavor mixing described by V_{MNS} having one-maximal and one-large mixing character can also be explained naturally with no other symmetry restriction. In our model, an origin of Cabibbo angle is the ratio λ=<|H_D^1|>_0 /<|H_D^2|>_0 and an origin of CP violation is the phase of H_D^1.

hep-ph↗

arXiv2005

Radiative Decays Involving $f_0(980)$ and $a_0(980)$ and Mixing Between Low and High Mass Scalar Mesons

We analyze the experimental data for $ϕ\to f_0(980)γ$, $ϕ\to a_0(980)γ$, $f_0(980)\toγγ$ and $a_0(980)\toγγ$ decay widths in a framework where $f_0(980)$ and $a_0(980)$ are assumed to be mainly $qq\bar{q}\bar{q}$ low mass scalar mesons and mixed with $q\bar{q}$ high mass scalar mesons. Applied the vector meson dominance model (VDM), these decays amplitudes are expressed by coupling parameters $B$ describing the S ($qq\bar{q}\bar{q}$ scalar meson)-V(vector meson)- V(vector meson) coupling and $B'$ describing the S' ($q\bar{q}$ scalar meson)-V-V coupling. Adopting the magnitudes for $B$ and $B'$ as $2.8{GeV^{-1}}$ and $12{GeV^{-1}}$, respectively, the mixing angle between $a_0(980)$ and $a_0(1450)$ as 9 degrees, and the mixing parameter $λ_{01}$ causing the mixing between I=0 $qq\bar{q}\bar{q}$ state and $q\bar{q}$ state as $0.24{GeV}^2$, we can interpret these experimental data, consistently.

hep-ph↗

arXiv2004

Wide-Area Mapping of 155 Micron Continuum Emission from the Orion Molecular Cloud Complex

We present the results of a wide-area mapping of the far-infrared continuum emission toward the Orion complex by using a Japanese balloon-borne telescope. The 155-um continuum emission was detected over a region of 1.5 deg^2 around the KL nebula with 3' resolution similar to that of the IRAS 100-um map. Assuming a single-temperature model of the thermal equilibrium dust, maps of the temperature and the optical depth were derived from the 155 um intensity and the IRAS 100 um intensity. The derived dust temperature is 5 - 15 K lower and the derived dust optical thickness were derived from the 155-um intensity and the IRAS 100-um intensity. The derived dust temperature is 5 - 15 K lower and the derived dust optical depth is 5 - 300 times larger than those derived from the IRAS 60 and 100-um intensities due to the significant contribution of the statistically heated very small grains to the IRAS 60-um intensity. The optical-thickness distribution shows a filamentary dust ridge that has a 1.5 degrees extent in the north - south direction and well resembles the Integral-Shaped Filament (ISF) molecular gas distribution. The gas-to-dust ratio derived from the CO molecular gas distribution along the ISF is in the range 30 - 200, which may be interpreted as being an effect of CO depletion due to the photodissociation and/or the freezing on dust grains.

astro-ph↗

arXiv2003

Effects to Scalar Meson Decays of Strong Mixing between Low and High Mass Scalar Mesons

We analyze the mass spectroscopy of low and high mass scalar mesons and get the result that the coupling strengths of the mixing between low and high mass scalar mesons are very strong and the strengths of mixing for $I=1, 1/2$ scalar mesons and those of I=0 scalar mesons are almost same. Next, we analyze the decay widths and decay ratios of these mesons and get the results that the coupling constants $A'$ for $I=1, 1/2$ which represents the coupling of high mass scalar meson $N'$ -> two pseudoscalar mesons $PP$ are almost same as the coupling $A'$ for the I=0. On the other hand, the coupling constant $A$ for $I=1, I=1/2$ which represents the low mass scalar meson $N$ -> $PP$ are far from the coupling constant $A$ for I=0. We consider a resolution for this discrepancy. Coupling constant $A''$ for glueball $G$ -> $PP$ is smaller than the coupling $A'$. $θ_P$ is $40^\circ \sim 50^\circ$.

hep-ph↗

arXiv2002

Neutrino Large Mixing in Universal Yukawa Coupling Model with Small Violation

We have analyzed the possibility that the universal Yukawa coupling (democratic mass matrix) with small violations of Dirac and Majorana neutrinos can induce the large mixing of neutrinos through the seesaw mechanism. The possibility can be achieved by the condition that the violation parameters of Majorana neutrinos are sufficiently smaller than the violation parameters of Dirac neutrinos. Allowed regions of the violation parameters producing the observed neutrino mass hierarchy and large neutrino mixing are not so restricted at present in contrast to the violation parameters for quark sector.

hep-ph↗

arXiv2001

Mixing among light scalar mesons and L=1 q\bar{q} scalar mesons

Following the re-establishment of the σ(600) and the κ(900), the light scalar mesons a_0(980) and f_0(980) together with the σ(600) and the κ(900) are considered as the chiral scalar partner of pseudoscalar nonet in SU(3) chiral symmetry, and the high mass scalar mesons a_0(1450), K^*_0(1430), f_0(1370) and f_0(1710) turned out to be considered as the L=1 q\bar{q} scalar mesons. We assume that the high mass of the L=1 q\bar{q} scalar mesons is caused by the mixing with the light scalar mesons. For the structure of the light scalar mesons, we adopted the qq\bar{q}\bar{q} model in order to explain the "scalar meson puzzle". The inter-mixing between the light scalar nonet and the high mass L=1 q\bar{q} nonet and the intra-mixing among each nonet are analyzed by including the glueball into the high mass scalar nonet.

hep-ph↗

arXiv2000

Small Violation of Universal Yukawa Coupling and Neutrino Large Mixing

We assume the universal Yukawa coupling (democratic mass matrix) with small violations for quarks, charged leptons and neutrinos masses. We could reproduce the mass hierarchy for quark masses and V_{CKM} matrix elements precisely. We adopt the see-saw mechanism for the explanation of smallness of neutrino masses and introduce the right-handed Majorana neutrinos and Dirac neutrinos. We assume the universal Yukawa coupling with small violations for Majorana and Dirac neutrinos. We can get the hierarchy of charged lepton masses and effective neutrino masses and the large mixing of neutrinos expressed in V_{NMS}.

hep-ph↗

arXiv2000

Analysis of atmospheric neutrino oscillations in three-flavor neutrinos

We analyze the atmospheric neutrino experiments of Super-Kamiokande (830-920 live days) using the three-flavor neutrino framework with the mass hierarchy m_1 nearly equal m_2 << m_3. We study the sub-GeV, multi- GeV neutrinos and upward through-going and stopping muons zenith angle distributions taking account of the Earth matter effects thoroughly. We obtain the allowed regions of mass and mixing parameters Delm^2_{23}, theta_{13} and theta_{23}. Delm^2_{23} is restricted to 0.002-0.01eV^2 and theta_{13}<13degrees, 35degrees<theta_{23}<55degrees in 90% C.L. For theta_{12}, there is no difference between the large angle solar neutrino solution and small one. From chi^2 fit, the minimum chi^2=55(54DOF) is obtained at Delm^2_{23}=4x10^(-3)eV^2, theta_{13}=10degrees and theta_{23} =45degrees.

hep-ph↗

arXiv1998

Atmospheric neutrino oscillations in three-flavor neutrinos

We analyzed the atmospheric neutrino experiments of SuperKamiokande including zenith angle dependence's using the three-flavor neutrino framework with the hierarchy m^2_1 \approx m^2_2<<m^2_3. Taking into account the terrestrial, solar neutrino experimental data and the atmospheric neutrino experiments including the sub-GeV and multi-GeV data in SuperKamiokande, large angle solution in the solar neutrino experiments is favored and the range of the mass parameter Deltam^2_{23} is restricted between 0.08eV^2 - 2eV^2. Allowed regions of mixing parameters are (theta_{13}<4degree, 27degree<theta_{23}< 32degree) for Delta m_{23}^2=1eV^2 and (theta_{13}<3degree, 28degree<theta_{23} <33degree) for Deltam_{23}^2=0.1 eV^2.

hep-ph↗

arXiv1998

Analysis of neutrino oscillation in three-flavor neutrinos

We analyzed the solar, terrestrial and atmospheric neutrinos experiments using the three-flavor neutrino framework and got the allowed regions for parameters (Δm_{12}^2, \sin^22θ_{12}, Δm_{23}^2, θ_{13}, θ_{23}). In solar neutrino experiments, we got the large angle solution (Δm_{12}^2, \sin^22θ_{12})=(4x10^{-6} - 7x10^{-5}eV^2, 0.6 - 0.9) and small angle solution (3x10^{-6} - 1.2x10^{-5}eV^2, 0.003 - 0.01) for θ_{13}=0^\circ - 20^\circ. From the terrestrial and atmospheric neutrino experiments, we got the allowed regions (θ_{13}<4^\circ, 24^\circ<θ_{23}<26^\circ) for Δm_{23}^2=2eV^2, (θ_{13}<4^\circ, 24^\circ<θ_{23} <45^\circ) for Δm_{23}^2=0.2eV^2 and (θ_{13}<14^\circ, θ_{23}=40^\circ) for Δm_{23}^2=0.02eV^2. It seems that the large angle solution for (Δm_{12}^2, \sin^22θ_{12}) is favored than the small angle slution from the analysis of zenith angle dependence in atmospheric neutrino sub-GeV experiment.

hep-ph↗

arXiv1997

Neutrino Mass and Mixing in the Universal Yukawa Coupling Framework

We present an analysis of neutrino oscillations which are consistent with current solar, atmospheric and terrestrial experiments in a framework with three neutrino mixing. The solutions satisfying these experiments have the large mixing (not maximal mixing) between electron neutrino- muon neutrino or muon neutrino-tau neutrino in m3 to be about several eV, where m3 is the heaviest neutrino mass. From these results, we conjecture a form for the mass matrices of charged lepton and neutrino which are described by the universal Yukawa coupling with small violations.

hep-ph↗