The supersymmetric grand unified theory where the $SU(5)$ gauge symmetry is broken by the Hosotani mechanism predicts the existence of adjoint chiral superfields whose masses are at the supersymmetry breaking scale. The Higgs sector is extended with the $SU(2{)}_L$ triplet with hypercharge zero and neutral singlet chiral multiplets from that in the minimal supersymmetric standard model. Since the triplet and singlet chiral multiplets originate from a higher-dimensional vector multiplet, this model is highly predictive. Properties of the particles in the Higgs sector are characteristic and can be different from those in the Standard Model and other models. We evaluate deviations in coupling constants of the standard model-like Higgs boson and the mass spectrum of the additional Higgs bosons. We find that our model is discriminative from the others by precision measurements of these coupling constants and masses of the additional Higgs bosons. This model can be a good example of grand unification that is testable at future collider experiments such as the luminosity upgraded Large Hadron Collider and future electron-positron colliders.

We explore the use of twisted boundary conditions in extracting the nucleon mass and the binding energy of two-baryon systems, such as the deuteron, from lattice QCD calculations. Averaging the results of calculations performed with periodic and antiperiodic boundary conditions imposed upon the light-quark fields, or other pairwise averages, improves the volume dependence of the deuteron binding energy from $\sim e^{-\kappa \mathrm{L}}/\mathrm{L}$ to $\sim e^{-\sqrt{2}\kappa \mathrm{L}}/\mathrm{L}$. However, a twist angle of $\pi /2$ in each of the spatial directions improves the volume dependence from $\sim e^{-\kappa \mathrm{L}}/\mathrm{L}$ to $\sim e^{-2\kappa \mathrm{L}}/\mathrm{L}$. Twist averaging the binding energy with a random sampling of twist angles improves the volume dependence from $\sim e^{-\kappa \mathrm{L}}/\mathrm{L}$ to $\sim e^{-2\kappa \mathrm{L}}/\mathrm{L}$, but with a standard deviation of $\sim e^{-\kappa \mathrm{L}}/\mathrm{L}$, introducing a signal-to-noise issue in modest lattice volumes. Using the experimentally determined phase shifts and mixing angles, we determine the expected energies of the deuteron states over a range of cubic lattice volumes for a selection of twisted boundary conditions.

We propose a theoretical framework for analyzing three-body hadronic $B$ meson decays based on the perturbative QCD approach. The crucial nonperturbative input is a two-hadron distribution amplitude for final states, whose timelike form factor and rescattering phase are fit to relevant experimental data. Together with the short-distance strong phase from the $b$-quark decay kernel, we are able to make predictions for direct $CP$ asymmetries in, for example, the $B^{\pm }\to {\pi }^{+}{\pi }^{-}{\pi }^{\pm }$ and ${\pi }^{+}{\pi }^{-}{K}^{\pm }$ modes, which are consistent with the LHCb data in various localized regions of phase space. Applications of our formalism to other three-body hadronic and radiative $B$ meson decays are mentioned.

Using $(106.41\pm 0.86)\times 10^6\psi (3686)$ events collected with the BESIII detector at BEPCII, we study for the first time the decay ${\chi }_{cJ}\to {\eta }^{\prime }{K}^{+}{K}^{-}$ ($J=1$, 2), where ${\eta }^{\prime }\to \gamma {\rho }^0$ and ${\eta }^{\prime }\to \eta {\pi }^{+}{\pi }^{-}$. A partial wave analysis in the covariant tensor amplitude formalism is performed for the decay ${\chi }_{c1}\to {\eta }^{\prime }{K}^{+}{K}^{-}$. Intermediate processes ${\chi }_{c1}\to {\eta }^{\prime }{f}_0(980)$, ${\chi }_{c1}\to {\eta }^{\prime }{f}_0(1710)$, ${\chi }_{c1}\to {\eta }^{\prime }{f_2}^{\prime }(1525)$ and ${\chi }_{c1}\to K_0^{*}(1430{)}^{\pm }{K}^{\mp }$ ($K_0^{*}(1430{)}^{\pm }\to {\eta }^{\prime }{K}^{\pm }$) are observed with statistical significances larger than $5\sigma$, and their branching fractions are measured.

Bottomoniumlike resonances $Z_b(10610)$ and $Z_b^{\prime }(10650)$ are good candidates to be hadronic molecules composed of $B{\overline{B}}^{*}$ (or $B^{*}\overline{B}$) and $B^{*}{\overline{B}}^{*}$, respectively. In this paper, considering $Z_b^{(\prime )}$ as heavy meson molecules, we investigate the decays of $Z_b^{(\prime )+}\to \mathrm{{\rm Y}}(nS){\pi }^{+}$ in terms of the heavy meson effective theory. We find that the intermediate $B^{(*)}$ and ${\overline{B}}^{(*)}$ meson loops and the form factors play a significant role in reproducing the experimental values of the decay widths. We also predict the decay widths of $Z_c^{+}\to J/\psi {\pi }^{+}$ and $\psi (2S){\pi }^{+}$ for a charmoniumlike resonance $Z_c$, which has recently been reported in experiments.

If the top quark is a composite state made out of some constituents, then its interaction with the gluon will be modified. We introduce the leading effective operators that contribute to the radius and anomalous magnetic moment of the top quark and study their effect on the cross section for $t\overline{t}$ production at the Tevatron and the LHC. Current measurements of the cross sections set a stringent limit on the scale of compositeness. This limit is comparable to similar limits obtained for light quarks and those from electroweak precision measurements. It can be used to constrain the parameter space of some composite Higgs models.

Since most of the neutrino parameters are well measured, we illustrate precisely the prediction of the Standard Model, minimally extended to allow massive neutrinos, for the electron neutrino magnetic moment. We elaborate on the effects of light sterile neutrinos on the effective electron neutrino magnetic moment measured at the reactors. We explicitly show that the kinematical effects of the neutrino masses are negligible even for light sterile neutrinos.

I consider a general two-Higgs-doublet model with $CP$ violation. I give a perturbative expansion for the mass eigenstates in terms of the small $CP$-violating phase. I use these analytical expressions to show that $\mathcal{O}({10}^{-2})$ $CP$ violation is allowed by the experimental bounds on the electron electric dipole moment in some regions of the parameter space. These regions also include parameters that are expected to give a strongly first-order electroweak phase transition required for electroweak baryogenesis. I also comment on how to incorporate the $CP$ violation into the searches for a strongly first-order electroweak phase transition which could explain the matter/antimatter asymmetry in the Universe.

Recent measurements of large ${\theta }_{13}$ by the reactor experiments have opened up the possibility of determining the neutrino mass hierarchy, i.e., the sign of the mass squared splitting $\mathrm{\Delta }{m}_{31}^2$, the $CP$-violating phase ${\delta }_{CP}$, and the octant of ${\theta }_{23}$. In light of this result, we study the performance of a low energy neutrino factory (LENF) for determination of the mass hierarchy. In particular, we explore the potential of the ${\nu }_e$ and ${\overline{\nu }}_e$ disappearance channels at LENF to determine the neutrino mass hierarchy, that is free from the uncertainties arising from the unknown ${\delta }_{CP}$ phase and the ${\theta }_{23}$ octant. We find that using these electron neutrino (antineutrino) disappearance channels with a standard LENF, it is possible to exclude the wrong hierarchy at $5\sigma$ with only 2 years of running, with a muon beam energy above $\sim 3.5(5.0–10.0)\mathrm{GeV}$ and baseline longer than $\sim 1400(1900–2400)\mathrm{km}$ for an optimistic (conservative) systematic error of 2% (5%).

We have measured the moment $A_{LU}^{\sin \varphi }$ corresponding to the polarized electron beam-spin asymmetry in semi-inclusive deep inelastic scattering. $A_{LU}^{\sin \varphi }$ is a twist-3 quantity providing information about quark-gluon correlations. Data were taken with the CLAS Spectrometer at Jefferson Lab using a 5.498 GeV longitudinally polarized electron beam and an unpolarized liquid hydrogen target. All three pion channels (${\pi }^{+}$, ${\pi }^0$ and ${\pi }^{-}$) were measured simultaneously over a large range of kinematics within the virtuality range $Q^2\approx 1.0–4.5{\mathrm{GeV}}^2$. The observable was measured with better than 1% statistical precision over a large range of $z$, $P_T$, $x_B$, and $Q^2$, which permits comparison with several reaction models. The discussed measurements provide an upgrade in statistics over previous measurements, and serve as the first evidence for the negative sign of the ${\pi }^{-}$ $\sin \varphi$ moment.

IsoDAR provides a pure and intense ${\overline{\nu }}_e$ source with an average energy of 6.5 MeV produced through ${}^8\mathrm{Li}$ $\beta$ decay. This source can be paired with a large scintillator detector, such as KamLAND, to produce a sample of ${\overline{\nu }}_e$-electron scatters that is more than 5 times larger than what has been collected before. Such a sample would allow for a 3.2% measurement of ${\sin }^2{\theta }_W$ and a sensitive search for nonstandard interactions.

We consider two self-dual Abelian Higgs systems obtained from Lorentz-breaking symmetry models by dimensional reduction. For the first model, we show that the self-dual equations are identical to those of Nielsen-Olesen vortices. Also, we show that our vortices have electric charge. In the second case we show that self-dual Chern-Simons-Higgs vortices without electric charge are possible.

A minimal supersymmetric braneworld model is presented which has (i) zero classical four-dimensional vacuum curvature, despite the large naive vacuum energy due to contributions from Standard Model particles and (ii) one-(bulk)-loop quantum corrections to the vacuum energy with a size set by the radius of the extra-dimensional spheroid. These corrections are technically natural because a Bogomol’nyi-Prasad-Sommerfield-like relation between the brane tension and $R$ charge—which would have preserved (half of) the bulk supersymmetry—is violated by the requirement that the stabilizing $R$-symmetry gauge flux be quantized. The extra-dimensional geometry is similar to previous rugby-ball geometries, but is simpler in that there is only one brane and so fewer free parameters. Although the sign of the renormalized vacuum energy ends up being the unphysical one for this model (in the limit considered here, where the massive bulk loop is the leading contribution), it serves as an illustrative example of the relevant physics.

Holographic principles have impacted the way we look at strong coupling phenomena in quantum chromodynamics, strongly interacting extensions of the standard model, and condensed-matter physics. In real world settings, however, we still lack understanding of why and when such an approach is justified. Therefore, here, without invoking any such principle a priori, we demonstrate how such a picture arises in the worldline formulation of quantum field theory. Among other connections to holographic models, a warped ${\mathrm{AdS}}_5$ geometry, a quantum mechanical picture, and hidden local symmetry emerge, as well as a Wilson flow (gradient flow), which extends the four-dimensional sources to five-dimensional fields, and a link to the Gutzwiller trace formula. The worldline formulation also reproduces the nonrelativistic case, which is important for condensed-matter physics.

The $(1+1)$-dimensional $\text{SU}(N)$ Yang-Mills Lagrangian, with bare mass $\mathcal{M}$ and gauge coupling $e$, naively describes gluons of mass $\mathcal{M}$. In fact, renormalization forces $\mathcal{M}$ to infinity. The system is in a confined phase, instead of a Higgs phase. The spectrum of this diverging-bare-mass theory contains particles of finite mass. There are an infinite number of physical particles, which are confined hadronlike bound states of fundamental colored excitations. These particles transform under irreducible representations of the global subgroup of the explicitly broken gauge symmetry. The fundamental excitations are those of the $\text{SU}(N)\times \text{SU}(N)$ principal chiral sigma model, with coupling $g_0=e/\mathcal{M}$. We find the masses of mesonlike bound states of two elementary excitations. This is done using the exact S matrix of the sigma model. We point out that the color-singlet spectrum coincides with that of the weakly coupled anisotropic $\mathrm{SU}(N)$ gauge theory in $2+1$ dimensions. We also briefly comment on how the spectrum behaves in the ’t Hooft limit, $N\to \infty$.

In a recent paper, a new parametrization for the dark matter (DM) speed distribution $f(v)$ was proposed for use in the analysis of data from direct detection experiments. This parametrization involves expressing the logarithm of the speed distribution as a polynomial in the speed $v$. We present here a more detailed analysis of the properties of this parametrization. We show that the method leads to statistically unbiased mass reconstructions and exact coverage of credible intervals. The method performs well over a wide range of DM masses, even when finite energy resolution and backgrounds are taken into account. We also show how to select the appropriate number of basis functions for the parametrization. Finally, we look at how the speed distribution itself can be reconstructed, and how the method can be used to determine if the data are consistent with some test distribution. In summary, we show that this parametrization performs consistently well over a wide range of input parameters and over large numbers of statistical ensembles and can therefore reliably be used to reconstruct both the DM mass and speed distribution from direct detection data.

We study (0,2) supersymmetric two-dimensional theories obtained by compactifying four-dimensional $N=1$ supersymmetric theories on a two-torus, with a magnetic field for a global $U(1)$ symmetry, and present evidence that Seiberg duality in four dimensions leads to an identification of different models of this type.

We investigate the chiral electric separation effect, where an axial current is induced by an electric field in the presence of both vector and axial chemical potentials, in a strongly coupled plasma via the Sakai-Sugimoto model with a $U(1{)}_R\times U(1{)}_L$ symmetry. By introducing different chemical potentials in $U(1{)}_R$ and $U(1{)}_L$ sectors, we compute the axial direct current (DC) conductivity stemming from the chiral current and the normal DC conductivity. We find that the axial conductivity is approximately proportional to the product of the axial and vector chemical potentials for arbitrary magnitudes of the chemical potentials. We also evaluate the axial alternating current (AC) conductivity induced by a frequency-dependent electric field, where the oscillatory behavior with respect to the frequency is observed.

We propose the almost-geodesic motion of self-gravitating test bodies as a possible selection rule among metric theories of gravity. Starting from a heuristic statement, the “gravitational weak equivalence principle,” we build a formal operative test able to probe the validity of the principle for any metric theory of gravity in an arbitrary number of spacetime dimensions. We show that, if the theory admits a well-posed variational formulation, this test singles out only the purely metric theories of gravity. This conclusion reproduces known results in the cases of general relativity (as well as with a cosmological constant term) and scalar-tensor theories, but extends also to debated or unknown scenarios, such as the $f(R)$ and Lanczos-Lovelock theories. We thus provide new tools going beyond the standard methods, where the latter turn out to be inconclusive or inapplicable.

The thermodynamic equilibrium states of a static thin ring shell in a ($2+1$)-dimensional spacetime with a negative cosmological constant are analyzed. Inside the ring, the spacetime is pure anti–de Sitter, whereas outside it is a Bañados-Teitelbom-Zanelli spacetime and thus asymptotically anti–de Sitter. The first law of thermodynamics applied to the thin shell, plus one equation of state for the shell’s pressure and another for its temperature, leads to a shell’s entropy, which is a function of its gravitational radius alone. A simple example for this gravitational entropy, namely, a power law in the gravitational radius, is given. The equations of thermodynamic stability are analyzed, resulting in certain allowed regions for the parameters entering the problem. When the Hawking temperature is set on the shell and the shell is pushed up to its own gravitational radius, there is a finite quantum backreaction that does not destroy the shell. One then finds that the entropy of the shell at the shell’s gravitational radius is given by the Bekenstein-Hawking entropy.