arXiv subjects

Muneyuki Ishida

Publications and source records attributed to Muneyuki Ishida.

At least 19 recordsLinked to original sources

arXiv2018

Finsler connection in moving frame formalism

In our previous work, we have defined a nonlinear connection of Finsler manifold which preserves the Finsler metric $L=L(x,dx)$. To make the method easier and more useful in applications, moving frame (vielbein) $θ^a={e^a}_μdx^μ$ formalism for the nonlinear connection is newly considered. We derive formulae to calculate the Finsler connection in the specific case that the Finsler metric depends not on coordinates $x^μ$, but only on moving frame $θ^a$: $L=L(θ)$.

math-ph↗

arXiv2018

Super Finsler Connection of Superparticle on Two Dimensional Curved Spacetime

We analyze the Casalbuoni-Brink-Schwarz superparticle model on a 2-dimensional curved spacetime as a super Finsler metric defined on a (2,2)-dimensional supermanifold. We propose a nonlinear Finsler connection which preserves this Finsler metric and calculates it explicitly. The equations of motion of the superparticle are reconstructed in the form of auto-parallel equations expressed by the super nonlinear connection.

hep-th↗

arXiv2017

Cusp singularity in mean field Ising model

An entropy of the Ising model in the mean field approximation is derived by the Hamilton-Jacobi formalism. We consider a grand canonical ensemble with respect to the temperature and the external magnetic field. A cusp arises at the critical point, which shows a simple and new geometrical aspect of this model. In educational sense, this curve with a cusp helps students acquire a more intuitive view on statistical phase transitions.

math-ph↗

arXiv2016

Killing Symmetry on Finsler Manifold

Killing vector fields $K$ are defined on Finsler manifold. The Killing symmetry is reformulated simply as $δK^\flat =0$ by using the Killing non-linear 1-form $K^\flat$ and the spray operator $δ$ with the Finsler non-linear connection. $K^\flat$ is related to the generalization of Killing tensors on Finsler manifold, and the condition $δK^\flat =0$ gives an analytical method of finding higher derivative conserved quantities, which may be called hidden conserved quantities. We show two examples: the Carter constant on Kerr spacetime and the Runge-Lentz vectors in Newtonian gravity.

gr-qc↗

arXiv2016

Variational principle of relativistic perfect fluid

We reformulate the relativistic perfect fluid system on curved space-time. Using standard variables, the velocity field $u$,energy density $ρ$ and pressure $p$, the covariant Euler-Lagrange equation is obtained from variational principle. This leads to the Euler equation and the equation of continuity in reparametrization invariant form.

gr-qc↗

arXiv2015

Energy-momentum conservation laws in Finsler/Kawaguchi Lagrangian formulation

We reformulate the standard Lagrangian formalism to a reparameterisation invariant Lagrangian formalism by means of Finsler and Kawaguchi geometry. In our formalism, various types of symmetries that appears in theories of physics are expressed geometrically by symmetries of Finsler (Kawaguchi) metric, and the conservation law of energy-momentum is a part of Euler-Lagrange equations. The application to scalar field, Dirac field, electromagnetic field and general relativity coupled to perfect fluid (added: ver.3) are discussed. By this formalism, we try to propose an alternative definition of energy-momentum current of gravity.

gr-qc↗

arXiv2012

Scalar-Top Masses from SUSY Loops with 125 GeV mh and precise Mw, mt

We constrain the masses of scalar-tops (stop) by analyzing the new precision Tevatron measurement of the W-boson mass and the LHC/Tevatron indications of a Higgs boson of mass 125.5+-1 GeV. Our study adopts Natural SUSY with low fine-tuning, which has multi-TeV first and second generation squarks and a light Higgsino mixing parameter mu=150 GeV. An effective Lagrangian calculation is made of mh to 3-loops using the H3m program with weak scale SUSY parameters obtained from RGE evolution from the GUT scale in the Natural SUSY scenario. The SUSY radiative corrections to the Higgs mass imply maximal off-diagonal elements of the stop mass-matrix and a mass splitting of the two stops larger than 400 GeV.

hep-ph↗

arXiv2012

Flavor-Tuned 125 GeV SUSY Higgs Boson at the LHC: MSSM and NATURAL SUSY TESTS

We show that an enhanced two-photon signal of the Higgs boson, h, observed with 125 GeV mass by the ATLAS and CMS collaborations, can be obtained if it is identified principally with the neutral $H_u^0$ of the two Higgs doublets of minimal Supersymmetry. We focus on sparticles and the pseudoscalar Higgs $A$ at the TeV scale. The off-diagonal element of the (Hu0,Hd0) mass matrix in the flavor basis must be suppressed, and this requires both a large Higgsino mass parameter, mu \sim TeV, and large tan beta. A MSSM sum rule is derived that relates gamma gamma and bb rates, and the gamma gamma enhancement predicts the bb reduction. On the contrary, Natural SUSY requires | mu | < 0.5 TeV, for which gamma gamma is reduced and $b\bar b$ is enhanced. This conclusion is independent of the mA-value and the SUSY quantum correction Deltab. Relative tau tau to bb rates are sensitive to Deltab.

hep-ph↗

arXiv2012

Total Width of 125 GeV Higgs Boson

By using the LHC and Tevatron measurements of the cross sections to various decay channels relative to the standard model Higgs boson, the total width of the putative 125 GeV Higgs boson is determined as 6.1 +7.7-2.9 MeV. We describe a way to estimate the branching fraction for Higgs decay to dark matter. We also discuss a No-Go theorem for the gammagamma signal of the Higgs boson at the LHC.

hep-ph↗

arXiv2012

Total Hadronic Cross Sections and π^\mp π^+ Scattering

Recent measurements of the inelastic and total proton-proton cross section at the LHC, and at cosmic ray energies by the Auger experiment, have quantitatively confirmed fits to lower energy data constrained by the assumption that the proton is asymptotically a black disk of gluons. We show that data on \bar p(p)p,π^\mp p, and K^\mp p forward scattering support the related expectation that the asymptotic behavior of all cross sections is flavor independent. By using the most recent measurements from ATLAS, CMS, TOTEM and Auger, we predict σ^{pp}_{\rm tot} (\sqrt s=8 {\rm TeV})=100.6 \pm 2.9 mb and σ^{pp}_{\rm tot} (\sqrt s=14 {\rm TeV})=110.8 \pm 3.5 mb, as well as refine the total cross section σ^{pp}_{\rm tot} (\sqrt s=57 {\rm TeV})=139.6 \pm 5.4 mb. Our analysis also predicts the total π^\mp π^+ cross sections as a function of \sqrt s.

hep-ph↗

arXiv2012

Randall-Sundrum Reality at the LHC

The radion is expected to be the first signal of the Randall-Sundrum (RS) model. We explore the possibility of finding it in the ongoing Higgs searches at the LHC. The little RS model (LRS), which has a fundamental scale at about 1000 TeV, is excluded over wide ranges of the radion mass from the latest $WW$ and gamma gamma data by ATLAS and CMS.

hep-ph↗

arXiv2012

Differentiating the Higgs boson from the dilaton and the radion at hadron colliders

A number of candidate theories beyond the standard model (SM) predict new scalar bosons below the TeV region. Among these, the radion, which is predicted in the Randall-Sundrum model, and the dilaton, which is predicted in spontaneous scale symmetry breaking, have very similar couplings to those of the SM Higgs boson, and it is very difficult to differentiate these three spin-0 particles in the expected signals of the Higgs boson at the LHC and Tevatron. We demonstrate that the observation of the ratio sigma(gamma gamma)/sigma(WW) gives a simple and decisive way, independently of the values of model parameters: the VEVs of the radion and dilaton fields.

hep-ph↗

arXiv2012

Dilaton at the LHC

The dilaton, a pseudo-Nambu-Goldstone boson appearing in spontaneous scale symmetry breaking at a TeV scale f, may be found in Higgs boson searches. The dilaton couples to standard model fermions and weak bosons with the same structure as the Higgs boson except for the overall strength. Additionally, the dilaton couples to a Higgs boson pair. The couplings of the dilaton to a gluon pair and a photon pair, appearing at loop level, are largely enhanced compared to the corresponding Higgs couplings. We present regions of the mass and VEV of the dilaton allowed by WW, ZZ, and gammagamma limits from the LHC at 7 TeV with 1.0-2.3 fb-1 integrated luminosity. A scale of f less than 1 TeV is nearly excluded. We discuss how the dilaton chi can be distinguished from the Higgs boson h by observation of the decays chi -> gammagamma and chi -> hh -> (WW)(WW).

hep-ph↗

arXiv2011

Rise of Kp Total Cross Section and Universality

The increase of the measured hadronic total cross sections at the highest energies is empirically described by squared log of center-of-mass energy sqrt s as sigma(tot)= B (log s)2, consistent with the energy dependence of the Froissart unitarity bound. The coefficient B is argued to have a universal value, but this is not proved directly from QCD. In the previous tests of this universality, the p(pbar)p, pi p, and K p forward scatterings were analyzed independently and found to be consistent with B(pp) = B(pip) = B(Kp), although the determined value of B(Kp) had large uncertainty. In the present work, we have further analyzed forward Kp scattering to obtain a more exact value of B(Kp). Making use of continuous moment sum rules(CMSR) we have fully exploited the information of low-energy scattering data to predict the high-energy behavior of the amplitude hrough duality. The estimation of B(Kp) is improved remarkably, and our result strongly supports the universality of B.

hep-ph↗

arXiv2009

Test of Universal Rise of Hadronic Total Cross Sections based on pi p, Kp and pbar p,pp Scatterings

Recently there are several evidences of the hadronic total cross section sigma(tot) to be proportional to B (log s)2 consistent with the Froissart unitarity bound. The COMPETE collaborations have further assumed sigma(tot) = B (log s/s0)2 + Z to extend its universal rise with the common value of B and s0 for all hadronic scatterings to reduce the number of adjustable parameters. The coefficient B was suggested to be universal in the arguments of colour glass condensate (CGC) of QCD in recent years. There has been, however, no rigorous proof yet based only on QCD. We attempt to investigate the value of B for pi+- p, K+- p and pbar p,pp scatterings respectively through the search for the simultaneous best fit to the experimental sigma(tot) and rho ratios at high energies. The sigma(tot) at the resonance and intermediate energy regions has also been exploited as a duality constraint based on the special form of finite-energy sum rule(FESR). We estimate the values of B, s0 and Z individually for pi+- p, K+- p and pbar p,pp scatterings without using the universality hypothesis. It turs out that the values of B are mutually consistent within one standard deviation. It has to be stressed that we cannot obtain such a definite conclusion without the duality constraint. It is also interesting to note that the values of Z for pi p, Kp and pbar(p)p approximately satisfy the ratio 2:2:3 predicted by the quark model. The obtained value of B for pbar(p)p is Bpp = 0.280 +- 0.015 mb, which predicts sigma(tot)(pp) =108.0 +- 1.9mb and rho(pp) =0.131+- 0.0025 at the LHC energy s^0.5 =14 TeV.

hep-ph↗

arXiv2008

Universal Rise of Hadronic Total Cross Sections based on Forward pi p and pbarp(pp) Scatterings

Recently there are several evidences of the increase of the total cross section sigma(tot) to be log2 s consistent with the Froissart unitarity bound, and the COMPETE collaborations in the PDG have further assumed sigma(tot) = B log2(s/s0) to extend its universal rise with a common value of B for all the hadronic scatterings. However, there is no rigorous proof yet based only on QCD. Therefore, it is worthwhile to prove this universal rise of sigma(tot) even empirically. In this letter we attempt to obtain the value of B for pi p scattering, B(pi p), with reasonable accuracy by taking into account the rich pi p data in all the energy regions. We use the finite-energy sum rule(FESR) expressed in terms of the pi p scattering data in the low and intermediate energies as a constraint between high-energy parameters. We then have searched for the simultaneous best fit to the sigma(tot) and rho ratios, the ratios of the real to imaginary parts of the forward scattering amplitudes. The lower energy data are included in the integral of FESR, the more precisely determined is the non-leading term such as log s, and then helps to determine the leading terms like log2 s. We have derived the value of B(pi p) as B(pi p)=0.311 +- 0.044mb. This value is to be compared with the value of B for pbarp,pp scattering, B(pp), in our previous analysis[11], B(pp)=0.289 +- 0.023mb. Thus, our result appears to support the universality hypothesis.

hep-ph↗

arXiv2007

Test of the Universal Rise of Hadronic Total Cross Sections at Super-high Energies

Saturation of the Froissart-Martin unitarity bound that the total cross sections increase like log2(s/s_0) appears to be confirmed. Due to this statement, the B log2(s/s_0) was assumed to extend the universal rise of all the total hadronic cross sections to reduce the number of adjustable parameters by the COMPETE Collaboration in the Particle Data Group (2006). Based on this assumption of parametrization, we test if the assumption on the universality of $B$ is justified through investigations of the value of B for pi p(K p)$ and pbar p, pp scatterings. We search for the simultaneous best fit to sigma(tot) and rho ratios, using a constraint from the FESR of the P' type for pi p scatterings and constraints which are free from unphysical regions for pbar p,pp and K p scatterings. By including rich informations of the low-energy scattering data owing to the use of FESR, the errors of B parameters decreases especially for pi p. The resulting value of B(pp) is consistent with B(pi p) within two standard deviation, which appears to support the universality hypothesis.

hep-ph↗

arXiv2006

Proposing a new constraint for predictions of pp, pbar p total cross sections and rho ratio at LHC

We propose a new constraint(1) corresponding to the FESR (with the moment n=-1) free from unphysical regions. Using this constraint(1) together with the constraint(2) (with the moment n=1), we search for the simultaneous best fit to the data points of sigma-tot and rho ratio up to the SPS energies to determine those values at higher energies. We then predict sigma-tot=107.1 +- 2.6 mb, rho=0.127 +- 0.004 at the LHC energy(E=14 TeV).

hep-ph↗