We discuss the relation between the concentration of the Brown-York mass and the formation of trapped surfaces in nonspherical massive systems. In particular, we formulate and prove a precise version of the Thorne hoop conjecture in conformally flat three-geometries sliced by equipotential foliation leaves. An intriguing relationship between the total rest mass and the Brown-York mass is shown. This is a further investigation of the previous work on the Brown-York mass hoop conjecture in spherical symmetry.

We consider hybrid inflation for small couplings of the inflaton to matter such that the critical value of the inflaton field exceeds the Planck mass. It has recently been shown that inflation then continues at subcritical inflaton field values where quantum fluctuations generate an effective inflaton mass. The effective inflaton potential interpolates between a quadratic potential at small field values and a plateau at large field values. An analysis of the allowed parameter space leads to predictions for the scalar spectral index $n_s$ and the tensor-to-scalar ratio $r$ similar to those of natural inflation. Using the ranges for $n_s$ and $r$ favored by the Planck data, we find that the energy scale of the plateau is constrained to the interval $(1.6–2.4)\times {10}^{16}\mathrm{GeV}$, which includes the energy scale of gauge coupling unification in the supersymmetric standard model. The tensor-to-scalar ratio is predicted to satisfy the lower bound $r>0.049$ for 60 $e$-folds before the end of inflation.

The inability to predict neutrino masses and the existence of dark matter are two essential shortcomings of the Standard Model. The Higgs triplet model provides an elegant resolution of neutrino masses via the seesaw mechanism. We show here that introducing vectorlike leptons in the model also provides a resolution to the problem of dark matter. We investigate constraints, including the invisible decay width of the Higgs boson and the electroweak precision variables, and impose restrictions on model parameters. We analyze the effect of the relic density constraint on the mass and Yukawa coupling of dark matter. We also calculate the cross sections for indirect and direct dark matter detection and show our model predictions for the neutrino and muon fluxes from the Sun, and the restrictions they impose on the parameter space. With the addition of vectorlike leptons, the model is completely consistent with dark matter constraints, in addition to improving electroweak precision and doubly charged mass restrictions, which are rendered consistent with present experimental data.

The LHC searches for the $CP$-odd Higgs boson $A$ are studied (with masses from 300 GeV to 1 TeV) in the context of the general two-Higgs-doublet model. With the discovery of the 125 GeV Higgs boson at the LHC, we highlight one promising discovery channel of $A\to hZ$. This channel can become significant for a heavy $CP$-odd Higgs boson after the global signal fitting to the 125 GeV Higgs boson in the general two-Higgs-doublet model. It is particularly interesting in the scenario where two $CP$-even Higgs bosons in the two-Higgs-doublet model have the common mass of 125 GeV. Since the final states involve a standard-model-like Higgs boson, we apply the jet substructure analysis of tagging the fat Higgs jet in order to eliminate the standard-model background sufficiently. After performing the kinematic cuts, we present the LHC search sensitivities for the $CP$-odd Higgs boson with mass up to 1 TeV via this channel.

In this paper, for the first time to our knowledge, a method is proposed to compute electromagnetic effects in hadronic processes, such as decays, using lattice simulations. The method can be applied, for example, to the leptonic and semileptonic decays of light or heavy pseudoscalar mesons. For these quantities the presence of infrared divergences in intermediate stages of the calculation makes the procedure much more complicated than is the case for the hadronic spectrum, for which calculations already exist. In order to compute the physical widths, diagrams with virtual photons must be combined with those corresponding to the emission of real photons. Only in this way do the infrared divergences cancel as first understood by Bloch and Nordsieck in 1937. We present a detailed analysis of the method for the leptonic decays of a pseudoscalar meson. The implementation of our method, although challenging, is within reach of the present lattice technology.

We report on lattice QCD results for the thermodynamic equation of state of quark-gluon matter obtained with $N_f=2$ degenerate quark flavors. For the fermion field discretization we are using the Wilson twisted mass prescription. Simulations have been carried out at three values of the bare quark masses corresponding to pion masses of $\sim 360$, $\sim 430$ and $\sim 640\mathrm{MeV}$. We highlight the importance of a good control of the lattice cutoff dependence of the trace anomaly which we have studied at several values of the inverse temperature $T^{-1}=a{N}_{\tau }$ with a timelike lattice extent up to $N_{\tau }=12$. We contrast our results with those of other groups obtained for $N_f=0$ and $N_f=2+1$. At low temperature we also confront them with hadron resonance gas model predictions for the trace anomaly.

The $\text{Higgs}+\text{jet}$ channel at the LHC is sensitive to the effects of new physics both in the total rate and in the transverse momentum distribution at high $p_T$. We examine the production process using an effective field theory (EFT) language and discussing the possibility of determining the nature of the underlying high-scale physics from boosted Higgs production. The effects of heavy color triplet scalars and top partner fermions with TeV scale masses are considered as examples and Higgs-gluon couplings of dimension five and dimension seven are included in the EFT. As a byproduct of our study, we examine the region of validity of the EFT. Dimension-seven contributions in realistic new physics models give effects in the high $p_T$ tail of the Higgs signal which are so tiny that they are likely to be unobservable.

We evaluate and discuss the impact of meson-exchange currents (MECs) on charged-current quasielastic neutrino cross sections. We consider the nuclear transverse response arising from two-particle two-hole states excited by the action of electromagnetic, purely isovector meson-exchange currents in a fully relativistic framework based on the work by the Torino Collaboration [A. D. Pace, M. Nardi, W. M. Alberico, T. W. Donnelly, and A. Molinari, Nucl. Phys. A726, 303 (2003)]. An accurate parametrization of this MEC response as a function of the momentum and energy transfers involved is presented. Results of neutrino-nucleus cross sections using this MEC parametrization together with a recent scaling approach for the one-particle one-hole contributions (named SuSAv2) are compared with experimental data.

The Lamb shift in muonic hydrogen was measured some time ago to a high accuracy. The theoretical prediction of this value is very sensitive to the proton finite-size effects. The proton radius extracted from muonic hydrogen is in contradiction with the results extracted from elastic electron-proton scattering. That creates a certain problem for the interpretation of the results from the muonic hydrogen Lamb shift. For the latter we need also to take into account the two-photon-exchange contribution with the proton finite size involved. The only way to describe it relies on the data from the scattering, which may produce an internal inconsistency of theory. Recently the leading proton-finite-size contribution to the two-photon exchange was found within the external field approximation. The recoil part of the two-photon-exchange has not been considered. Here we revisit calculation of the external-field part and take the recoil correction to the finite-size effects into account.

We present a measurement of neutrino oscillations via atmospheric muon neutrino disappearance with three years of data of the completed IceCube neutrino detector. DeepCore, a region of denser IceCube instrumentation, enables the detection and reconstruction of atmospheric muon neutrinos between 10 and 100 GeV, where a strong disappearance signal is expected. The IceCube detector volume surrounding DeepCore is used as a veto region to suppress the atmospheric muon background. Neutrino events are selected where the detected Cherenkov photons of the secondary particles minimally scatter, and the neutrino energy and arrival direction are reconstructed. Both variables are used to obtain the neutrino oscillation parameters from the data, with the best fit given by $\mathrm{\Delta }{m}_{32}^2={2.72}_{-0.20}^{+0.19}\times {10}^{-3}{\mathrm{eV}}^2$ and ${\sin }^2{\theta }_{23}={0.53}_{-0.12}^{+0.09}$ (normal mass ordering assumed). The results are compatible, and comparable in precision, to those of dedicated oscillation experiments.

I calculate the top quark forward-backward asymmetry at the Tevatron in both the laboratory frame and the $t\overline{t}$ rest frame. I show that soft-gluon corrections are the dominant contribution to the asymmetry and closely approximate exact results through next-to-next-to-leading order (NNLO). I present a calculation of the asymmetry including approximate next-to-next-to-next-to-leading-order ($\mathrm{N}{}^3\mathrm{LO}$) soft-gluon contributions from next-to-next-to-leading-logarithm resummation as well as electroweak corrections. Thus approximate $\mathrm{N}{}^3\mathrm{LO}$ ($\mathrm{a}\mathrm{N}{}^3\mathrm{LO}$) results are obtained, which significantly enhance and improve previous NNLO results. The theoretical $\mathrm{a}\mathrm{N}{}^3\mathrm{LO}$ result for the top quark forward-backward asymmetry at the Tevatron in the laboratory frame is $(6.8\pm 0.3)\%$, and in the $t\overline{t}$ rest frame it is $(10.0\pm 0.6)\%$ which is in excellent agreement with recent Tevatron data.

We elaborate on the role of extremal surfaces probing the internal space in AdS/CFT dualities. Extremal surfaces in anti–de Sitter space quantify the “geometric” entanglement between different regions in physical space for the dual conformal field theory. This, however, is just one of many ways to split a given system into subsectors, and extremal surfaces in the internal space should similarly quantify entanglement between subsectors of the theory. For the case of ${\mathrm{AdS}}_5\times {\mathrm{S}}^5$, their area was interpreted as entanglement entropy between $\mathsf{U}(n)$ and $\mathsf{U}(m)$ subsectors of $\mathsf{U}(n+m)$ $\mathcal{N}=4$ super Yang-Mills theory (SYM). Making this proposal precise is subtle for a number of reasons, the most obvious being that from the bulk one usually has access to gauge-invariant quantities only, while a split into subgroups is inherently gauge variant. We study $\mathcal{N}=4$ SYM on the Coulomb branch, where some of the issues can be mitigated and the proposal can be sharpened. Continuing back to the original ${\mathrm{AdS}}_5\times {\mathrm{S}}^5$ geometry, we obtain a modified proposal, based on the relation of the internal space to the R-symmetry group.

Extending the results of [1,2] on the holographic representation of local gauge field operators in anti–de Sitter space, here we construct the bulk operators for higher spin gauge fields at the leading order in $\frac{1}{N}$ expansion. Working in the holographic gauge for higher spin gauge fields, we show that gauge field operators with integer spin $s>1$ can be represented by an integration over a ball region, which is the interior region of the spacelike bulk light cone on the boundary. The construction is shown to be anti–de Sitter covariant up to gauge transformations, and the two-point function between higher spin gauge fields and the boundary higher spin current exhibits singularities on both bulk and boundary light cones. We also comment on a possible extension to the level of three-point functions and carry out a causal construction for higher spin fields in de Sitter spacetime.

We study transport phenomena of total angular momentum in holography, as a first step toward holographic understanding of spin transport phenomena. Spin current, which has both the local Lorentz index for spins and the space-time vector index for current, couples naturally to the bulk spin connection. Therefore, the bulk spin connection becomes the source for the boundary spin current. This allows us to evaluate the spin current holographically, with a relation to the stress tensor and metric fluctuations in the bulk. We examine the spin transport coefficients and the thermal spin Hall conductivity in a simple holographic setup.

We study the influence of a background magnetic field on the melting of the $J/\psi$ vector meson by introducing a Born-Infeld modification of the soft-wall model. Out of the three polarizations of the massive vector meson, we find that the longitudinal one (parallel to the applied magnetic field) melts only at an even higher temperature than the deconfinement temperature, whereas the two transverse polarizations melt at a lower temperature than in the absence of a magnetic field. We also conduct a preliminary investigation of the effect of the magnetic field on the heavy quark diffusion coefficient, showing an increased diffusion constant for the longitudinal polarization with respect to the transverse polarizations.

It is known that any nondegenerate Lagrangian containing time derivative terms higher than first order suffers from the Ostrogradsky instability, pathological excitation of positive and negative energy degrees of freedom. We show that, within the framework of analytical mechanics of point particles, any Lagrangian for third order equations of motion, which evades the nondegeneracy condition, still leads to the Ostrogradsky instability. Extension to the case of higher odd order equations of motion is also considered.

Two different solutions to the problem of the zero-mode localization of the Elko spinor are presented. The first solution is given by the introduction of a mass term and by coupling the spinor with the brane through a delta function. The second solution is reached by a Yukawa geometrical coupling with the Ricci scalar. These two models consistently change the boundary condition at infinity and at the origin. For the case of the geometrical coupling, we are able to show that the zero mode is localized for any smooth version of the Randall-Sundrum model.

This paper explores the conjecture that large-$N_c$ gauge theories have a Hagedorn spectrum, if, and only if, they are confining and possess an explicit or emergent center symmetry. Evidence in support of this conjecture is presented. Many classes of large-$N_c$ gauge theories are considered. In all cases, we find that theories for which there exists a strong plausibility argument for a Hagedorn spectrum at large $N_c$ are also believed to be confining and possess either an explicit center symmetry or have a strong plausibility argument for the existence of an emergent center symmetry at large $N_c$. Conversely, all theories we consider which are believed not to have a Hagedorn spectrum at large $N_c$, either were known to not be confining or else were believed to lack an emergent center symmetry. This is consistent with expectations based on the conjecture.

The aim of this work is to compute the entanglement entropy of real and virtual particles by rewriting the generating functional of ${\varphi }^4$ theory as a mean value between states and observables defined through the correlation functions. Then the von Neumann definition of entropy can be applied to these quantum states and in particular, for the partial traces taken over the internal or external degrees of freedom. This procedure can be done for each order in the perturbation expansion showing that the entanglement entropy for real and virtual particles behaves as $\ln (m_0)$. In particular, entanglement entropy is computed at first order for the correlation function of two external points showing that mutual information is identical to the external entropy and that conditional entropies are negative for all the domain of $m_0$. In turn, from the definition of the quantum states, it is possible to obtain general relations between total traces between different quantum states of a ${\varphi }^r$ theory. Finally, discussion about the possibility of taking partial traces over external degrees of freedom is considered, which implies the introduction of some observables that measure space-time points where an interaction occurs.

In this paper, we assume that the asymptotically anti-de Sitter (AdS) black hole thermodynamics parameters are identical with those of the polytropic gas. We find an asymptotically AdS solution of Einstein’s equations in which the thermodynamics matches that of a special case of polytropic gas. The energy-momentum tensor corresponding to our solution obeys three energy conditions.