In this paper, we study rare semileptonic decays of the |$B_c$| meson in the context of type-I, II, and III two Higgs doublet models. We follow the relativistic quark model for parameterizing the form factors used in matrix elements of weak transitions between the corresponding meson states. We investigate observables such as branching ratio, lepton polarization asymmetry, forward–backward asymmetry

We apply independent component analysis (ICA) to real data from a gravitational wave detector for the first time. Specifically, we use the iKAGRA data taken in April 2016, and calculate the correlations between the gravitational wave strain channel and 35 physical environmental channels. Using a couple of seismic channels which are found to be strongly correlated with the strain, we perform ICA. Injecting

We investigate the shear viscosity of massless classical scalar fields in the |$\phi^4$| theory on a lattice by using the Green–Kubo formula. Based on the scaling property of the classical field, the shear viscosity is represented using a scaling function. The equilibrium expectation value of the time-correlation function of the energy–momentum tensor is evaluated as the ensemble average of the classical

Chiral symmetry restoration of quarks is investigated at finite density in quantum chromodynamics. The critical chemical potentials at zero temperature, in which the chiral symmetry is restored, are calculated with the Schwinger-Dyson equation in the real-time formalism without the instantaneous exchange approximation. We present some properties of the quark mass functions and the quark propagators

In this paper, new analytic formulas for one-loop contributing to Higgs decay channel |$H \rightarrow Z\gamma$| are presented in terms of hypergeometric functions. The calculations are performed by following the technique for tensor one-loop reduction developed in [A. I. Davydychev, Phys. Lett. B 263 (1991) 107]. For the first time, one-loop form factors for the decay process are shown which are valid

We propose a novel mechanism to reproduce the observed mass hierarchy for scalar mesons lighter than 1 GeV (called the inverse hierarchy), regarding them as mesons made of a quark and an anti-quark (⁠|$q\bar{q}$| mesons). The source is provided by the SU(3) flavor-symmetry breaking induced by the U(1) axial anomaly. In particular, the anomaly term including the explicit chiral symmetry breaking plays

We present a flavor model with |$S_3$| modular invariance in the framework of SU(5) grand unified theory (GUT). The |$S_3$| modular forms of weights |$2$| and |$4$| give the quark and lepton mass matrices with a common complex parameter, the modulus |$\tau$|⁠. The GUT relation of down-type quarks and charged leptons is imposed by the vacuum expectation value (VEV) of the adjoint 24-dimensional Higgs

We analyze excited baryon states using a holographic dual of quantum chromodynamics that is defined on the basis of an intersecting D4/D8-brane system. Studies of baryons in this model have been made by regarding them as a topological soliton of a gauge theory on a five-dimensional curved spacetime. However, this allows one to obtain only a certain class of baryons. We attempt to present a framework

Type II string theory or M-theory contains a broad spectrum of gauge potentials. In addition to the standard |$p$|-form potentials, various mixed-symmetry potentials have been predicted, which may couple to exotic branes with non-standard tensions. Together with |$p$|-forms, mixed-symmetry potentials turn out to be essential to build the multiplets of the |$U$|-duality symmetry in each dimension. In

A dynamically transversely trapping surface (DTTS) is a new concept for an extension of a photon sphere that appropriately represents a strong gravity region and has close analogy with a trapped surface. We study formation of a marginally DTTS in time-symmetric, conformally flat initial data with two black holes, with a spindle-shaped source, and with a ring-shaped source, and clarify that |$\mathcal{C}\lesssim

In |$U$|-duality-manifest formulations, supergravity fields are packaged into covariant objects such as the generalized metric and |$p$|-form fields |$\mathcal A_p^{I_p}$|⁠. While a parameterization of the generalized metric in terms of supergravity fields is known for |$U$|-duality groups |$E_n$| with |$n\leq 8$|⁠, a parameterization of |$\mathcal A_p^{I_p}$| has not been fully determined. In this

We discuss a supersymmetric extension of a non-relativistic Chern–Simons matter theory, known as the supersymmetric Jackiw–Pi model, in a harmonic trap. We show that the non-relativistic version of the superconformal symmetry, called the super-Schrödinger symmetry, is not spoiled by an external field including the harmonic potential. It survives as a modified symmetry whose generators have explicit

We propose a new reaction mechanism for the study of strange and charmed baryon production. In this mechanism we consider the correlation of two quarks in baryons, so it can be called the two-quark process. As in the previously studied one-quark process, we find large production rates for charmed baryons in comparison with strange baryons. Moreover, the new mechanism causes the excitation of both the

We present an efficient quantum router using a fully-engineered one-dimensional tight-binding array acting as quantum data bus. Quantum routing is achieved by weakly coupling the sender and the receivers to the data bus. We show that perfect transfer of a state between sender and a chosen receiver can be achieved via appropriately tuning the on-site energy applied on the site of the sender. A generalization

We use the time-dependent Ginzburg–Landau equation to describe a type-II superconductor in a magnetic field in the presence of both strong thermal fluctuations and an artificial pinning array. Thermal fluctuations are represented by the Langevin white noise. The layered structure of the superconductor is taken into accounted with the Lawrence–Doniach model. The self-consistent Gaussian approximation

The type IIB matrix model is a promising candidate for a nonperturbative formulation of superstring theory. As such, it is expected to explain the origin of space–time and matter at the same time. This has been partially demonstrated by the previous Monte Carlo studies on the Lorentzian version of the model, which suggested the emergence of (3+1)-dimensional expanding space–time. Here we investigate

We propose a method to reconstruct smeared spectral functions from two-point correlation functions measured on the Euclidean lattice. An arbitrary smearing function can be considered as long as it is smooth enough to allow an approximation using Chebyshev polynomials. We test the method with numerical lattice data of charmonium correlators. The method provides a framework to compare lattice calculation

It is inferred that, in addition to the Coulomb and Newtonian forces, there should exist a third fundamental long-range force, which acts between intrinsic angular momenta. This inference is based on the quantum Einstein gravity, that is, the manifestly-covariant, BRS-invariant, canonically quantized theory of general relativity. The form of the potential of the third fundamental long-range force is

The null results of the LHC searches have put strong bounds on new physics scenarios such as supersymmetry (SUSY). With the latest values for the top quark mass and strong coupling, we study the upper bounds on the sfermion masses in split SUSY from the observed Higgs boson mass and electroweak (EW) vacuum stability. To be consistent with the observed Higgs mass, we find that the largest values of

To introduce novel ways of manipulating the skyrmion dynamics we need to develop new fundamental models. Many-particle quantum hydrodynamics allows us to study inter-skyrmion interactions in the approximation of point-particle skyrmions, which were discovered in multiferroic insulators, where the spiral magnetic structure is accompanied by a finite electric dipole moment. We propose a new model of

For more than half a century, the structure of |$^{12}$|C, such as the ground band, has been understood to be well described by the three |$\alpha$| cluster model based on a geometrical crystalline picture. On the contrary, recently it has been claimed that the ground state of |$^{12}$|C is also well described by a nonlocalized cluster model without any of the geometrical configurations originally

The superconformal index of quiver gauge theories realized on D3-branes in toric Calabi–Yau cones is investigated. We use the AdS/CFT correspondence and study D3-branes wrapped on supersymmetric cycles. We focus on brane configurations in which a single D3-brane is wrapped on a cycle, and we do not take account of branes with multiple wrapping. We propose a formula that gives finite-|$N$| corrections

|$f(R)$| theory is a modification of Einstein’s general relativity which has provided many interesting results in cosmology and astrophysics. To derive a black hole solution in this theory is difficult due to the fact that it contains fourth-order differential equations. In this study, we use the first reliable deviation from general relativity which is given by the quadratic form of |$f(R)=R+\beta

In the framework of the flipped 3-3-1 model introduced recently [R. M. Fonseca and M. Hirsch, J. High Energy Phys. 1608, 003 (2016)], the lepton-flavor-violating (LFV) decay |$\mu \rightarrow 3e$| was predicted to have a large branching ratio (Br) close to the recent experimental limit. We will show that the Br of LFV decays of the standard-model-like (SM-like) Higgs boson decays (LFVHD) Br|$(h\rightarrow

We propose a nonperturbative formulation of the Atiyah–Patodi–Singer (APS) index in lattice gauge theory in four dimensions, in which the index is given by the |$\eta$| invariant of the domain-wall Dirac operator. Our definition of the index is always an integer with a finite lattice spacing. To verify this proposal, using the eigenmode set of the free domain-wall fermion we perturbatively show in

We propose a bottom-up approach in which a structure of high-energy physics is explored by accumulating existence proofs and/or no-go theorems in the standard model or its extension. As an illustration, we study fermion mass hierarchies based on an extension of the standard model with vector-like fermions. It is shown that the magnitude of elements of Yukawa coupling matrices can become |$O(1)$| and

We have investigated the status of the nuclear fuel assemblies in the Unit-1 reactor of the Fukushima Daiichi nuclear power plant by cosmic muon radiography. In this study, muon tracking detectors were placed outside the reactor building. We succeeded in identifying the inner structure of the reactor complex, such as the reactor containment vessel, pressure vessel, and other structures of the reactor

We show that there exist scalar field theories with plausible one-particle states in general |$D$|-dimensional nonstationary curved spacetimes whose propagating modes are localized on |$d\le D$| dimensional hypersurfaces, and the corresponding stress tensor resembles the bare cosmological constant |$\lambda_{\rm B}$| in the |$D$|-dimensional bulk. We show that nontrivial |$d=1$| dimensional solutions

A singly heavy baryon can be viewed as |$N_c-1$| (⁠|$N_c$| being the number of colors) light valence quarks bound by the pion mean fields that are created by the presence of the |$N_c-1$| valence quarks self-consistently, while the heavy quark inside a singly heavy baryon is regarded as a static color source. We investigate how the pion mean fields are created by the presence of |$N_c$|⁠, |$N_c-1$|⁠

In the language of black hole physics, Hawking radiation is one of the most controversial subjects about which there exist lots of puzzles, including the information loss problem and the question of whether this radiation is thermal or not. In this situation, a possible way to face these problems is to bring quantum effects into play, also taking into account self-gravitational effects in the scenario

It is widely believed that classical gravity breaks down and quantum gravity is needed to deal with a singularity. We show that there is a class of spacetime curvature singularities which can be resolved with metric and matter field transformations. As an example, we consider an anisotropic power-law inflation model with scalar and gauge fields in which a space-like curvature singularity exists at

Energy conditions for matter fields are comprehensively investigated in arbitrary |$n(\ge 3)$| dimensions without specifying future and past directions locally. We classify an energy–momentum tensor into |$n$|-dimensional counterparts of the Hawking–Ellis types I to IV, where type III is defined by a more useful form than those adopted by Hawking and Ellis and other authors to identify the type-III

As some neutron star transients require an additional unknown heat source (referred to as “shallow heating”) to explain their high temperatures at the beginning of quiescence, we investigate the effect of shallow heating as well as compressional heating on the thermal state of transiently accreting neutron stars with the use of evolutionary calculations in the present work. Through comparing our theoretical

In the positron–electron annihilation process, finite deviations from the standard calculation based on Fermi’s golden rule are suggested in recent theoretical work. This paper describes an experimental test of the predictions of this theoretical work by searching for events with two photons from positron annihilation of energy larger than the electron rest mass (⁠|$511\,{\rm keV}$|⁠). The positrons

Mathieu’s equation originally emerged while studying vibrations on an elliptical drumhead, so naturally, being a linear second-order ordinary differential equation with a Cosine periodic potential, it has many useful applications in theoretical and experimental physics. Unfortunately, there exists no closed-form analytic solution of Mathieu’s equation, so that future studies and applications of this

A framework to represent and compute two-loop |$N$|-point Feynman diagrams as double-integrals is discussed. The integrands are “generalised one-loop type” multi-point functions multiplied by simple weighting factors. The final integrations over these two variables are to be performed numerically, whereas the ingredients involved in the integrands, in particular the “generalised one-loop type” functions

We study holographic entanglement entropy in four-dimensional quantum gravity with negative cosmological constant. By using the replica trick and evaluating path integrals in the minisuperspace approximation, in conjunction with the Wheeler–DeWitt equation, we compute quantum corrections to the holographic entanglement entropy for a circular entangling surface on the boundary three-sphere. Similarly

The radii and tidal deformabilities of neutron stars are investigated in the framework of the relativistic mean-field (RMF) model with different density-dependent behaviors of symmetry energy. To study the effects of symmetry energy on the properties of neutron stars, |$\omega$| meson and |$\rho$| meson coupling terms are included in a popular RMF Lagrangian, i.e., the TM1 parameter set, which is adopted

In the leading order of the large-|$N$| approximation, we study the renormalon ambiguity in the gluon (or, more appropriately, photon) condensate in the 2D supersymmetric |$\mathbb{C}P^{N-1}$| model on |$\mathbb{R}\times S^1$| with the |$\mathbb{Z}_N$| twisted boundary conditions. In our large-|$N$| limit, the combination |$\Lambda R$|⁠, where |$\Lambda$| is the dynamical scale and |$R$| is the |$S^1$|

AbstractNatural gadolinium is widely used for its excellent thermal neutron capture cross section, because of its two major isotopes: $^{\rm 155}$Gd and $^{\rm 157}$Gd. We measured the $\gamma$-ray spectra produced from the thermal neutron capture on targets comprising a natural gadolinium film and enriched $^{\rm 155}$Gd (in Gd$_{2}$O$_{3}$ powder) in the energy range from 0.11 MeV to 8.0 MeV, using

Computations of the primordial black hole (PBH) mass function discussed in the literature have conceptual issues. They stem from the fact that the mass function is a differential quantity and the standard criterion of the PBH formation from the seed primordial fluctuations cannot be directly applied to the computation of the differential quantities. We propose a new criterion of the PBH formation,

Gauge/gravity correspondence is regarded as a powerful tool for the study of strongly coupled quantum systems, but its proof is not available. An unresolved issue that should be closely related to the proof is what kind of correspondence exists, if any, when gauge theory is weakly coupled. We report progress about this limit for the case associated with D|$p$|-branes (⁠|$0\le p\le 4$|⁠), namely, the

It was recently shown that in four-dimensional |$SU(N)$| Nambu–Jona-Lasinio (NJL) type models, the |$SU(N)$| symmetry breaking into its special subgroups is not special but much more common than that into the regular subgroups, where the fermions belong to complex representations of |$SU(N)$|⁠. We perform the same analysis for the |$SO(N)$| NJL model for various |$N$| with fermions belonging to an

We use a microscopic multicluster model to investigate the structure of |$^{10}{\rm Be}$| and of |$^{11}{\rm Be}$|⁠. These nuclei are described by |$\alpha +\alpha+n+n$| and |$\alpha +\alpha+n+n+n$| configurations, respectively, within the Generator Coordinate Method (GCM). The 4- and 5-body models raise the problem of a large number of generator coordinates (6 for |$^{10}{\rm Be}$| and 9 for |$^{11}{\rm

A family of algebras |$\mathcal{E}_n$| that extends the Lie algebra of the Drinfel’d double is proposed. This allows us to systematically construct the generalized frame fields |$E_A{}^I$| which realize the proposed algebra by means of the generalized Lie derivative, i.e., |$\hat{\pounds}_{E_A}E_B{}^I =-\mathcal{F}_{AB}{}^C\,E_C{}^I$|⁠. By construction, the generalized frame fields include a twist

Natural gadolinium is widely used for its excellent thermal neutron capture cross section, because of its two major isotopes: |$^{\rm 155}$|Gd and |$^{\rm 157}$|Gd. We measured the |$\gamma$|-ray spectra produced from the thermal neutron capture on targets comprising a natural gadolinium film and enriched |$^{\rm 155}$|Gd (in Gd|$_{2}$|O|$_{3}$| powder) in the energy range from 0.11 MeV to 8.0 MeV