In the composite Higgs models, originally proposed by Georgi and Kaplan, the Higgs boson is a pseudo Nambu-Goldstone boson (pNGB) of spontaneous breaking of a global symmetry. In the minimal version of such models, global SO(5) symmetry is spontaneously broken to SO(4), and the pNGBs form an isospin doublet field, which corresponds to the Higgs doublet in the Standard Model (SM). Predicted coupling constants of the Higgs boson can in general deviate from the SM predictions, depending on the compositeness parameter. The deviation pattern is determined also by the detail of the matter sector. We comprehensively study how the model can be tested via measuring single and double production processes of the Higgs boson at the LHC and future electron-positron colliders. The possibility to distinguish the matter sector among the minimal composite Higgs models is also discussed. In addition, we point out differences in the cross section of double Higgs boson production from the prediction in other new physics models.

We determine the first correction to the quadrupole operator in high-energy QCD beyond the transverse momentum dependent (TMD) limit of Weizsäcker-Williams and linearly polarized gluon distributions. These functions give rise to isotropic, respectively, $\sim \cos 2\varphi$ angular distributions in deep inelastic scattering (DIS) dijet production. On the other hand, the correction produces a $\sim \cos 4\varphi$ angular dependence which is suppressed by one additional power of the dijet transverse momentum scale (squared) $P^2$.

Nuclear effects on neutrino reactions are expected to be a significant complication in current and future neutrino oscillation experiments seeking precision measurements of neutrino flavor transitions. Calculations of these nuclear effects are hampered by a lack of experimental data comparing neutrino reactions on free nucleons to neutrino reactions on nuclei. We present results from a novel technique that compares neutrino and antineutrino charged current quasielastic scattering on hydrocarbons to extract a cross section ratio of antineutrino charged current elastic reactions on free protons to charged current quasielastic reactions on the protons bound in a carbon nucleus. This measurement of nuclear effects is compared to models.

We present our recent progress on the relativistic modeling of electron-nucleus reactions and compare our predictions with inclusive ${}^{12}\mathrm{C}$ ($e$, $e^{\prime }$) experimental data in a wide kinematical region. The model, originally based on the superscaling phenomenon shown by electron-nucleus scattering data, has recently been improved through the inclusion of relativistic mean field theory effects that take into account the enhancement of the quasielastic transverse scaling function compared with its longitudinal counterpart. In this work, we extend the model to include the complete inelastic spectrum—resonant, nonresonant and deep inelastic scattering. We also discuss the impact of meson-exchange currents through the analysis of two-particle two-hole contributions to electromagnetic response functions evaluated within the framework of the relativistic Fermi gas, considering for the first time not only the transverse but also the longitudinal channel. The results show quite good agreement with data over the whole range of energy transfer, including the dip region between the quasielastic peak and the $\mathrm{\Delta }$ resonance.

The $CPT$-odd and Lorentz-violating Carroll-Field-Jackiw (CFJ) modification of electrodynamics is discussed, and we study its effects on the energy spectrum of hydrogen, as well as in the generation of a momentum-dependent electric dipole moment for charged leptons. We also briefly comment on the possibility of the detection of Lorentz violation in measurements of vacuum birefringence in resonant cavities. The bounds found are based on local laboratory experimental limits and are not competitive with the ones coming from astrophysical considerations.

In this paper, we discuss two features of the noncommutative geometry and spectral action approach to the Standard Model: the fact that the model is inherently Euclidean, and that it requires a quadrupling of the fermionic degrees of freedom. We show how the two issues are intimately related. We give a precise prescription for the Wick rotation from the Euclidean theory to the Lorentzian one, eliminating the extra degrees of freedom. This requires not only projecting out mirror fermions, as has been done so far, and which leads to the correct Pfaffian, but also the elimination of the remaining extra degrees of freedom. The remaining doubling has to be removed in order to recover the correct Fock space of the physical (Lorentzian) theory. In order to get a spin(1, 3)-invariant Lorentzian theory from a spin(4)-invariant Euclidean theory, such an elimination must be performed after the Wick rotation. Differences between the Euclidean and Lorentzian case are described in detail, in a pedagogical way.

We investigate puncture statistics based on the covariant area spectrum in loop quantum gravity. First, we consider Maxwell-Boltzmann statistics with a Gibbs factor for punctures. We establish formulas which relate physical quantities such as horizon area to the parameter characterizing holographic degrees of freedom. We also perform numerical calculations and obtain consistency with these formulas. These results tell us that the holographic bound is satisfied in the large area limit and the correction term of the entropy-area law can be proportional to the logarithm of the horizon area. Second, we also consider Bose-Einstein statistics and show that the above formulas are also useful in this case. By applying the formulas, we can understand intrinsic features of Bose-Einstein condensate which corresponds to the case when the horizon area almost consists of punctures in the ground state. When this phenomena occurs, the area is approximately constant against the parameter characterizing the temperature. When this phenomena is broken, the area shows rapid increase which suggests the phase transition from quantum to classical area.

For $O(4)$-symmetric instantons, there are two complementary interpretations for their analytic continuations. One is the nothing-to-something interpretation, where the initial and final hypersurfaces are disconnected by Euclidean manifolds. The other is the something-to-something interpretation, introduced by Brown and Weinberg, where the initial and final hypersurfaces are connected by the Euclidean manifold. These interpretations have their own pros and cons and hence they are complementary. In this paper, we consider analytic continuations of thin-shell instantons that have less symmetry, i.e., the spherical symmetry. When we consider the Farhi-Guth-Guven/Fischler-Morgan-Polchinski tunneling, the something-to-something interpretation has been used in the usual literature. On the other hand, we can apply the nothing-to-something interpretation with some limited conditions. We argue that for both interpretations, we can give the consistent decay rate. As we apply and interpret what follows the nothing-to-something interpretation, a stationary black hole can emit an expanding shell that results in a spacetime without a singularity or event horizon.

By considering the behavior of the reduced action under the scaling transformation, we present a unified derivation of the Smarr-like relation for asymptotically anti-de-Sitter planar black holes. This novel Smarr-like relation leads to useful information in the condensed matter systems through the AdS/CMT correspondence. By using our results, we provide an efficient way to obtain the holographically renormalized on-shell action without the information on the explicit forms of counter terms. We find the complete consistency of our results with those in various models discussed in the recent literatures and obtain new implications.

Past holographic screens are codimension-one surfaces of indefinite signature that are foliated by marginally antitrapped surfaces called leaves. Future holographic screens are defined similarly except with marginally trapped leaves. Bousso and Engelhardt recently showed that the leaves of past and future holographic screens have monotonic area. We prove a stronger area law that shows that subregions of leaves also have monotonic area. For every past and future holographic screen, there exists a family of leaf-orthogonal curves called the fibration of the screen. Any region in a leaf can be translated along the fibration to a leaf of larger area. Our result states that the area of the subregion grows as it is translated.

Motivated by a solution to the strong $CP$ problem, we propose a model where a new heavy neutral $CP$-even Higgs boson couples to vectorlike quarks enhancing its production cross section whose dominant decays are into weak bosons. The masses of the vectorlike quarks are generated through interactions with a singlet scalar field charged under a broken global $U(1)$ symmetry, providing a solution to the strong $CP$ problem by means of the Peccei-Quinn mechanism. The diboson excess observed by the ATLAS Collaboration is discussed as the new heavy Higgs boson is a candidate to explain a possible signal in this channel. We also show that the 14 TeV LHC is capable of discovering this heavy Higgs with masses up to 1 TeV in the $H\to ZZ\to {\ell }^{+}{\ell }^{-}{\ell }^{\prime +}{\ell }^{\prime -}$ search channel using boosted decision trees to better discriminate between signals and backgrounds and to tame systematic uncertainties in the background rates.

If the LHC should fail to observe direct signals for new physics, it may become necessary to look for new physics effects in rare events such as flavor-changing decays of the top quark, which, in the standard model, are predicted to be too small to be observed. We set up the theoretical framework in which experimentally accessible results can be expected in models of new physics, and go on to discuss two models of supersymmetry—one with conserved $R$-parity, and one without $R$-parity—to illustrate how the flavor-changing signals are predicted in these models. In the latter case, there is a distinct possibility of detecting the rare decay $t\to c+Z^0$ at the LHC. We also present a detailed set of very general formulas which can be used to make similar calculations in diverse models of new physics.

We calculate the energy gap (latent heat) and pressure gap between the hot and cold phases of the SU(3) gauge theory at the first order deconfining phase transition point. We perform simulations around the phase transition point with the lattice size in the temporal direction $N_t=6$, 8 and 12 and extrapolate the results to the continuum limit. We also investigate the spatial volume dependence. The energy density and pressure are evaluated by the derivative method with nonperturabative anisotropy coefficients. We adopt a multipoint reweighting method to determine the anisotropy coefficients. We confirm that the anisotropy coefficients approach the perturbative values as $N_t$ increases. We find that the pressure gap vanishes at all values of $N_t$ when the nonperturbative anisotropy coefficients are used. The spatial volume dependence in the latent heat is found to be small on large lattices. Performing extrapolation to the continuum limit, we obtain $\mathrm{\Delta }\epsilon /T^4=0.75\pm 0.17$ and $\mathrm{\Delta }(\epsilon -3p)/T^4=0.623\pm 0.056$.

We consider a charged scalar particle $\chi$ of mass around 375 GeV charged under both $\mathrm{SU}(3{)}_{\mathit{C}}$ and a new confining non-Abelian gauge interaction. After pair production, these interactions confine the exotic scalar into nonrelativistic bound states whose decays into photons can explain the 750 GeV diphoton excess observed at the LHC. Taking the new confining group to be SU(2), we find $\chi$ must carry an electric charge of $Q\sim [\frac{1}{2},1]$ to fit the data. Interestingly, we find that pair production of the scalars and the subsequent formation of the bound state dominates over direct bound state resonance production. This explanation is quite weakly constrained by current searches and data from the forthcoming run at the LHC will be able to probe our scenario more fully. In particular dijet, monojet, di-Higgs, and $\text{jet}+\text{photon}$ searches may be the most promising discovery channels.

As the pion mass approaches a critical value $m_{\pi }^{\star }$ from below, an $S$-wave resonance crosses the pion-baryon threshold and becomes a bound state with arbitrarily small binding energy, thus driving the scattering length to diverge. I explore the consequences of chiral symmetry for the values of $m_{\pi }$ close to $m_{\pi }^{\star }$. It turns out that chiral symmetry is crucial for an $S$-wave resonance to be able to stand very near the threshold and in the meantime to remain narrow, provided that the mass splitting is reasonably small. The effective range of pion-baryon scattering is unexpectedly large, proportional to $4\pi f_{\pi }^2/m_{\pi }^3$ when $m_{\pi }$ is around $m_{\pi }^{\star }$. As a result, this unexpected large length scale causes universality relations to break down much sooner than naively expected.

We propose an open/closed string duality in general backgrounds extending previous ideas about open string completeness by Ashoke Sen. Our proposal sets up a general version of holography that works in gravity as a tomographic principle. We argue, in particular, that previous expectations of a supergravity/Dirac-Born-Infeld (DBI) correspondence are naturally embedded in this conjecture and can be tested in a well-defined manner. As an example, we consider the correspondence between open string field theories on extremal D-brane setups in flat space in the large-$N$, large ’t Hooft limit, and asymptotically flat solutions in ten-dimensional type II supergravity. We focus on a convenient long-wavelength regime, where specific effects of higher-spin open string modes can be traced explicitly in the dual supergravity computation. For instance, in this regime we show how the full Abelian DBI action arises from supergravity as a straightforward reformulation of relativistic hydrodynamics. In the example of a ($2+1$)-dimensional open string theory this reformulation involves an Abelian Hodge duality. We also point out how different deformations of the DBI action, related to higher-derivative corrections and non-Abelian effects, can arise in this context as deformations in corresponding relativistic hydrodynamics.

In this work we focus on the quantum Einstein-Yang-Mills sector quantized by the methods of loop quantum gravity. We point out the improved UV behavior of the coupled system as compared to pure quantum Yang-Mills theory on a fixed, classical background spacetime as was considered in a seminal work by Kogut and Susskind. Furthermore, we develop a calculational scheme by which the fundamental spectrum of the quantum Yang-Mills Hamiltonian can be computed in principle and by which one can make contact with the Wilsonian renormalization group, possibly purely within the Hamiltonian framework. Finally, we comment on the relationship of the fundamental spectrum to that of pure Yang-Mills theory on a (flat) classical spacetime.

We present a novel approach for setting initial conditions on the mode functions of the Mukhanov-Sasaki equation. These conditions are motivated by minimization of the renormalized stress-energy tensor and are valid for setting a vacuum state even in a context where the spacetime is changing rapidly. Moreover, these alternative conditions are potentially observationally distinguishable. We apply this to the kinetically dominated universe and compare with the more traditional approach.

We discuss direct and indirect probes of chirality-flipping couplings of the top quark to Higgs and gauge bosons, considering both $CP$-conserving and $CP$-violating observables, in the framework of the Standard Model effective field theory. In our analysis we include current and prospective constraints from collider physics, precision electroweak tests, flavor physics, and electric dipole moments (EDMs). We find that low-energy indirect probes are very competitive, even after accounting for long-distance uncertainties. In particular, EDMs put constraints on the electroweak $CP$-violating dipole moments of the top that are 2 to 3 orders of magnitude stronger than existing limits. The new indirect constraint on the top EDM is given by $|d_t|<5\times {10}^{-20}e\mathrm{cm}$ at 90% C.L.