arXiv subjects

Yoshimasa Kurihara

Publications and source records attributed to Yoshimasa Kurihara.

At least 19 recordsLinked to original sources

arXiv2025

Quantum GraviElectro Dynamics

This report presents a possible attempt at renormalisable quantum gravity based on the standard BRST quantisation used for Yang-Mills theory. We have provided the BRST invariant Lagrangian of the gravitationally interacting U(1) gauge theory, namely the Quantum GraviElectro Dynamics (QGED), including the gauge fixing and the ghost Lagrangian. We have extracted a set of Feynman rules in the local inertial frame where gravity locally vanishes from this Lagrangian. Using the Feynman rules of the QGED constructed here, we have built all the renormalisation constants and show that the theory is perturbatively renormalisable, at least in the one-loop order. All infinite naked objects in the naked Lagrangian can replace experimentally measured ones. In addition to the standard QED parameters, we have shown that the gravitational coupling constant can be experimentally measured. We have also discussed a running effect of the gravitational coupling constant and the perturbative estimation of the Hawking radiation as examples of perturbative QGED. The difference between our theory and the widely known un-renormalisable quantum general relativity is clarified.

hep-ph↗

arXiv2025

Yang-Mills-Utiyama Theory and Graviweak Correspondence

This report provides a geometrical Yang-Mills theory, including gravity. The theory treats the space-time symmetry of the local Lorentz group in the same manner as the internal gauge symmetry. We extend this general relativistic Yang-Mills theory in the Minkowski space-time to a broader space, including Euclidean and Minkowskian spaces. In the extended space, we can transport topological achievements from the Euclidean Yang-Mills theory into the Lorentzian Yang-Mills theory. This extension also provides a relation between space-time and internal symmetry. The perspective provided by the extended theory suggests the novel relation between gravity and the weak force, leading us to the graviweak correspondence.

gr-qc↗

arXiv2025

Green's function in general relativity

This report provides Green's functions (classical propagators) of gravitational fields appearing in general relativity. The existence of Green's function of the wave equation in curved space with an indefinite metric is ensured owing to the Hodge harmonic analysis. The analyticity of Green's function is determined intrinsically to keep a causality. This report proposed a novel definition of momentum space in curved space-time and the linearisation of the Einstein equation as a free field consistent with that of the Yang-Mills gauge field. The proposed linearisation does not utilize the weak-field approximation; thus, the method applies to highly caved space-time. We gave two examples of Green's function of gravitational fields: the plane wave solution and the Schwarzschild solution.

gr-qc↗

arXiv2025

Two Higgs doublet model fitting and $t\bar{t}b\bar{b}$ signal at the ILC

One of the most straightforward extensions of the standard model (SM) is having an additional Higgs doublet to the SM, namely the two Higgs doublet models(THDM). In the type-I model, an additional Higgs doublet is introduced that does not couple to any fermion via the Yukawa interaction in the original Lagrangian. Considering various theoretical and phenomenological constraints, we have found the best-fitted parameter set in the type-I model using the minimum $χ^2$ method by scanning the model's parameter space. We show that this optimal parameter set can be tested by precisely analyzing the decay processes $D^+_s \rightarrow τ^+ ν_τ$, $D^+ \rightarrow μ^+ ν_μ$, and $B^0 \rightarrow K^* μ^+ μ^-$. Moreover, the decay channels $h \rightarrow γγ$ and $Zγ$ can be used to distinguish the model from the SM. For a direct search of the model at future colliders, we have proposed an investigation of the $e^+e^- \rightarrow t\bar{t} b\bar{b}$ process at the ILC to detect the new physics of the model. Considering the initial state radiation correction and applying appropriate background cuts, the calculation result of the scattering cross section shows that it is feasible to observe a clear and unique signal in the $t\bar{b}$ invariant mass distribution corresponding to the charged Higgs pair creations.

hep-ph↗

arXiv2025

Topological indices of general relativity and Yang-Mills theory in four-dimensional space-time

This report investigates general relativity and the Yang-Mills theory in four-dimensional space-time using a common mathematical framework, the Chern-Weil theory for principal bundles. The whole theory is described owing to the fibre bundle with the GL(4) symmetry by twisting several principal bundles with the gauge symmetry. In addition to the principal connection, we introduce the Hodge-dual connection into the Lagrangian to make gauge fields have dynamics independent from the Bianchi identity. We show that the duplex superstructure appears in the bundle when a Z2-grading operator exists in the total space of the bundle in general. The Dirac operator appears in the secondary superspace using the one-dimensional Clifford algebra, and it provides topological indices from the Atiyah-Singer index theorem. Though the topological index is usually discussed in the elliptic-type manifold, this report treats it in the hyperbolic-type space-time manifold using a novel method, the theta-metric space. The theta-metric treats the Euclidean and Minkowski spaces simultaneously and defines the topological index in the Minkowski space-time.

gr-qc↗

arXiv2023

Gravitational Effect on Fundamental Physical Observables

This report studies possible gravitational effects on measurements of fundamental physical observables such as the fine structure constant and the lepton magnetic moment. Although a static gravitational potential does not contribute to physical observables owing to Einstein's equivalent principle, a dynamic degree with finite momentum transfer can contribute to them. In other words, a laboratory frame fixed on the Earth is not an inertial system; thus, Earth's gravity can contribute to local observables. We investigate experimental results measuring the fine structure constant and electron and muon magnetic moments using the quantum field theoretic method under the Schwarzschild background field. We prepare classical vierbein and spin-connection fields owing to the Schwarzschild metric in the momentum space of the local Lorentz space and estimate possible gravitational effects at the surface of the Earth as ${\mathcal O}(10^{-9})$, which is consistent with the current discrepancy between measured and calculated values of the muon anomalous magnetic moment. On the other hand, the gravitational effect does not contribute to the fine structure constant measurements. We propose a possible test of gravitational effects in particle physics using precise measurement of muon properties in the J-PARK.

gr-qc↗

arXiv2022

Full Electroweak O(alpha) corrections to Higgs boson production processes with the beam polarization at the International Linear Collider

We present the full O(alpha) electroweak radiative corrections to 9 Higgs boson production with the beam polarization at the International Linear Collider(ILC). The computation is performed with the help of GRACE-Loop. We compared the full O(alpha) electroweak radiative corrections with the factorized initial state radiation(ISR) effects to estimate the pure weak corrections. This reveals the pure weak corrections are not negligible and should be taken into account for the precision measurements of the Higgs boson property at the ILC experiments.

hep-ph↗

arXiv2022

Quantum effects of black holes and cosmological constant problem

We propose a quantum gravity equation owing to the geometrical quantization of general relativity, namely the Schrödinger-Einstein equation. Quantum effects of a Schwarzschild black hole are demonstrated by solving the quantum equation requiring a stationary phase; the consistent result is obtained using the Einstein-Brillouin-Keller (EBK) quantization condition. We solve the Schrödinger--Einstein equation around the classical solution of the McVittie-Thakurta metric. This solution simultaneously describes a system with Schwarzschild's black holes and a scalar field. Moreover, we investigate a possible interplay between quantum black holes and a scalar field. The number density of black holes in the universe is obtained by applying statistical mechanics to a system consisting of black holes and a scalar field. A possible solution to the cosmological constant problem is proposed from a statistical perspective.

physics.gen-ph↗

arXiv2021

Higgs triplet extension of GRACE

Much theoretical effort and automatization are required to confront new physics models with experimental data for many types of particle reactions at future colliders. In this context, we extend GRACE, an automatic calculation system for invariant amplitudes, to incorporate particles and interactions in the Georgi-Machacek model. With the extended GRACE system, we study fermiophobic Higgs boson production processes at $e^+ e^-$ and $e^- e^-$ colliders in the model. The results show some advantages of $e^- e^-$ colliders over $e^+ e^-$ colliders for new physics search and thus its complementary role.

hep-ph↗

arXiv2021

Nakanishi-Kugo-Ojima quantization of general relativity in Heisenberg picture

The Chern-Weil topological theory is applied to a classical formulation of general relativity in four-dimensional spacetime. Einstein--Hilbert gravitational action is shown to be invariant with respect to a novel translation (co-translation) operator up to the total derivative; thus, a topological invariant of a second Chern class exists owing to Chern-Weil theory. Using topological insight, fundamental forms can be introduced as a principal bundle of the spacetime manifold. Canonical quantization of general relativity is performed in a Heisenberg picture using the Nakanishi-Kugo-Ojima formalism in which a complete set of quantum Lagrangian and BRST transformations including auxiliary and ghost fields is provided in a self-consistent manner. An appropriate Hilbert space and physical states are introduced into the theory, and the positivity of these physical states and the unitarity of the transition matrix are ensured according to the Kugo-Ojima theorem. The nonrenormalizability of quantum gravity is reconsidered under the formulation proposed herein.

gr-qc↗

arXiv2020

Symplectic structure for general relativity and Einstein-Brillouin-Keller quantization

The Hamiltonian system of general relativity and its quantization without any matter or gauge fields are discussed on the basis of the symplectic geometrical theory. A symplectic geometry of classical general relativity is constructed using a generalized phase space for pure gravity. Prequantization of the symplectic manifold is performed according to the standard procedure of geometrical quantization. Quantum vacuum solutions are chosen from among the classical solutions under the Einstein-Brillouin-Keller quantization condition. A topological correction of quantum solutions, namely the Maslov index, is realized using a prequantization bundle. In addition, a possible mass spectrum of Schwarzschild black holes is discussed.

gr-qc↗

arXiv2020

Tau $g-2$ at $e^-e^+$ colliders with momentum dependent form factor

The deviation between the standard model prediction and the measurement of the muon g-2 is currently at 3-4 sigma (can be up to 7 sigma in the upcoming experiment E989). If new physics is responsible for such discrepancy, it is expected that the new contributions to tau g-2 are even larger than that for muon due to its large mass. In spite of that, the tau g-2 is much more difficult to be directly measured because of its short lifetime. In this paper, we consider the effect of the tau g-2 at $e^-e^+$ colliders in a model independent way. Using the tau pair production channel at the Large Electron Position Collider (LEP), we have found the allowed range for the new physics contribution of the tau g-2 assuming a $q^2$-dependence ansatz for the magnetic form factor. In our analysis, we take into account the standard model one-loop correction as well as the initial state photon radiation. We have also investigated the prospect at future $e^-e^+$ colliders, and determine the expected allowed range for the new physics contribution to the tau g-2. Given the proposed beam polarization configuration at the International Linear Collider (ILC), we have analyzed the dependence of this allowed range on the integrated luminosity as well as the relative systematic error.

hep-ph↗

arXiv2019

ISR effects on loop corrections of a top pair-production at the ILC

Precise predictions for an $e^+e^-\rightarrow t\bar{t}$ cross-section are presented in the energy region from 400 GeV to 800 GeV. Cross-sections are estimated including the beam-polarization effects with full $\mathcal{O}(α)$, and also with the effects of the initial-state photon emission. A radiator technique is used for the initial-state photon emission up to two-loop orders. In this investigation, a weak correction is defined as the full electroweak corrections without the initial-state photonic corrections. As a result, it is determined that the total cross-section of a top quark pair-production receives the weak corrections of $+4\%$ over the trivial initial state corrections at a center of mass energy of 500 GeV. Among the initial state contributions, a contribution from two-loop diagrams gives less than $0.11\%$ correction over the one-loop ones at the center of mass energies of from $400$ GeV to $800$ GeV. In addition, the effect of a running coupling constant is also discussed.

hep-ph↗

arXiv2018

PHOTON-2017 conference proceedings

This document collects the proceedings of the PHOTON 2017 conference ("International Conference on the Structure and the Interactions of the Photon", including the 22th "International Workshop on Photon-Photon Collisions", and the "International Workshop on High Energy Photon Colliders") held at CERN (Geneva) in May 2017. The latest experimental and theoretical developments on the topics of the PHOTON conference series are covered: (i) $γ\,γ$ processes in e$^+$e$^-$, proton-proton (pp) and nucleus-nucleus (AA) collisions at current and future colliders, (ii) $γ$-hadron interactions in e$^\pm$p, pp, and AA collisions, (iii) final-state photon production (including Standard Model studies and searches beyond it) in pp and AA collisions, and (iv) high-energy $γ$-ray astrophysics. These proceedings are dedicated to the memory of Maria Krawczyk.

hep-ph↗

arXiv2018

One-loop effects of MSSM particles in e^-e^+ \to Zh and e^-e^+ \to ν\barνh at the ILC

The 1-loop effects of the MSSM at the ILC are investigated through numerical analysis. We studied the higgs production processes $e^-e^+\rightarrow Zh$ and $e^-e^+\rightarrow ν\barνh$ at the ILC. It is found that the magnitude of the MSSM contribution through the 1-loop effects is sizable enough to be detected. In the study, three sets of the MSSM parameters are proposed, which are consistent with the observed higgs mass, the muon $g$-$2$, the dark matter abundance and the decay branching ratios of $B$ mesons. In the $e^-e^+\rightarrow Zh$ process, the 1-loop effects of the MSSM are visible and the distinction of the parameter sets is partially possible. For the study of $e^-e^+\rightarrow ν\barνh$, we used the equivalent $\it W$-boson approximation in the evaluation of the 1-loop cross section. While the 1-loop effect of the MSSM is visible, the distinction of the parameter sets might not be possible in this process under the value of realistic luminosity at the ILC.

hep-ph↗

arXiv2018

GR@PPA 2.9: radiation matching for simulating photon production processes in hadron collisions

We release an event generator package, GR@PPA 2.9, for simulating the direct (single) photon and diphoton (double photon) production in hadron collisions. The included programs were used in our previous studies, in which we have explicitly shown large contributions from parton-associated processes. The programs consistently combine simulations based on matrix elements with parton-shower simulations that reproduce the multiple parton radiation and quark fragmentation to photons. The matrix elements include associated parton production processes up to two partons. We provide instructions for the installation and execution of the programs in this article. The practical performance is also presented.

hep-ph↗

arXiv2018

$\mathcal{O}(α^2)$ ISR effects with a full electroweak one-loop correction for a top pair-production at the ILC

Precise predictions for an $e^+e^-\rightarrow t\bar{t}$ cross section are presented at an energy region from 400 GeV to 800 GeV. Cross sections are estimated including the beam-polarization effects with full $\mathcal{O}(α)$, and also with effects of the initial-state photon emission. A radiator technique is used for the initial-state photon emission up to two-loop order. A weak correction is defined as the full electroweak corrections without the initial-state photonic corrections. As a result, it is obtained that the total cross section of a top quark pair-production receives the weak corrections of $+4\%$ over the trivial initial state corrections at a centre of mass energy of 500 GeV. Among the initial state contributions, a contribution from two-loop diagrams gives less than $0.11\%$ correction over the one-loop ones at the center of mass energies of from $400$ GeV to $800$ GeV. In addition, an effect of a running coupling constant is also discussed.

hep-ph↗

arXiv2018

Geometrothermodynamics for Black holes and de Sitter Space

In this report, a general method to extract thermodynamic quantities from solutions of the Einstein equation is developed. In 1994, Wald established that the entropy of a black hole could be identified as a Noether charge associated with a Killing vector of a global space-time (pseudo-Riemann) manifold. We reconstruct Wald's method using geometrical language, e.g$.$, via differential forms defined on the local space-time (Minkowski) manifold. Concurrently, the abstract thermodynamics are also reconstructed using geometrical terminology, which is parallel to general relativity. The correspondence between the thermodynamics and general relativity can be seen clearly by comparing the two expressions. This comparison requires a modification of Wald's method. The new method is applied to Schwarzschild, Kerr, and Kerr--Newman black holes and de Sitter space. The results are consistent with previous results obtained using various independent methods. This strongly supports the validity of the area theorem for black holes.

gr-qc↗