We consider a certain $\mathcal{N}=1$ supersymmetric, $\mathrm{SO}(3)\times \mathrm{SO}(3)$ invariant, subsector of the dyonic ISO(7)-gauged maximal supergravity in four dimensions. The theory contains two scalar fields and two pseudoscalar fields. We look for stationary points of the scalar potential, especially the one preserving $\mathcal{N}=3$ supersymmetry of the original ISO(7) gauged theory. The $\mathcal{N}=3$ stationary point corresponding to the AdS vacuum in the $D=4$ theory is lifted to a warped ${\mathrm{AdS}}_4\times X_6$ type solution in massive type IIA supergravity. This $D=10$ background should be the dual of a certain $\mathcal{N}=3$ Chern-Simons matter theory in three dimensions.

By using the symmetry improved Cornwall-Jackiw-Tomboulis effective formalism, we study a pion string of the $O(4)$ linear sigma model at finite temperature in chiral limit. In terms of the Kibble-Zurek mechanism we reconsider the production and evolution of the pion string in a thermal bath. Finally, we estimate the pion string density and its possible signal during the chiral phase transition.

In this paper, using a ($2+1$)-dimensional field theory approach, we study the Aharonov-Bohm (AB) scattering with Lorentz symmetry breaking. We obtain the modified scattering amplitude to the AB effect due to the small Lorentz violation correction in the breaking parameter and prove that up to one loop the model is free from ultraviolet divergences.

Using the gauge-gravity duality, we have obtained the potential between a heavy quark and an antiquark pair, which is moving perpendicular to the direction of orientation, in a strongly coupled supersymmetric hot plasma. For this purpose we work on a metric in the gravity side, viz. Ouyang–Klebanov–Strassler black hole geometry, of which the dual in the gauge theory side runs with the energy and hence proves to be a better background for thermal QCD. The potential obtained has a confining term both in the vacuum and in a medium, in addition to the Coulomb term alone, usually reported in the literature. As the velocity of the pair is increased, the screening of the potential gets weakened, which may be understood by the decrease of the effective temperature with the increase of the velocity. The crucial observation of our work is that, beyond a critical separation of the heavy quark pair, the potential develops an imaginary part which is nowadays understood to be the main source of dissociation. The imaginary part is found to vanish at small $r$, thus agreeing with the perturbative result. Finally we have estimated the thermal width for the ground and first excited states and found that nonzero rapidities lead to an increase of thermal width. This implies that the moving quarkonia dissociate more easily than the static ones, which agrees with other calculations. However, the width in our case is larger than other calculations due to the presence of confining terms.

Many different cosmological models have been proposed to address the cosmological constant problem and the coincidence problem. We compare here four different models that can be used to describe an effective (time-dependent) cosmological constant $\mathrm{\Lambda }(z)$. A numerical analysis of the $\mathrm{\Lambda }(z)$ evolution obtained for each model shows that it can be used for distinguishing between all four models. We calculate next the $\omega (\mathrm{\Lambda })$ frequencies for quasinormal modes of gravitational perturbations of Schwarzschild-de Sitter black holes at different redshifts. Considering that the variation of $\mathrm{\Lambda }$ happens on cosmological time scales, the combined $\omega (\mathrm{\Lambda }(z))$ could be used in principle to track the evolution of the cosmological constant. We quantify the resulting minute frequency shift in the quasinormal mode frequencies and show that the relative frequency shift grows as $M^2$. However, even in a most optimistic scenario with an extremely high mass supermassive black hole there is no prospect for the detection of this effect.

The gravitational radiation emitted during the merger of a black hole with a neutron star is rather similar to the radiation from the merger of two black holes when the neutron star is not tidally disrupted. When tidal disruption occurs, gravitational waveforms can be broadly classified in two groups, depending on the spatial extent of the disrupted material. Extending previous work by some of us, here we present a phenomenological model for the gravitational waveform amplitude in the frequency domain encompassing the three possible outcomes of the merger: no tidal disruption, and “mild” and “strong” tidal disruption. The model is calibrated to 134 general-relativistic numerical simulations of binaries where the black hole spin is either aligned or antialigned with the orbital angular momentum. All simulations were produced using the SACRA code and piecewise polytropic neutron star equations of state. The present model can be used to determine when black-hole binary waveforms are sufficient for gravitational-wave detection, to extract information on the equation of state from future gravitational-wave observations, to obtain more accurate estimates of black hole-neutron star merger event rates, and to determine the conditions under which these systems are plausible candidates as central engines of gamma-ray bursts and macronovae/kilonovae.

We study a static, spherically symmetric and asymptotic flat spacetime, assuming the hypersurface orthogonal Einstein-aether theory with an ultraviolet modification motivated by the Hořava-Lifshitz theory, which is composed of the $z=2$ Lifshitz scaling terms such as scalar combinations of a three-Ricci curvature and the acceleration of the aether field. For the case with the quartic term of the acceleration of the aether field, we obtain a two-parameter family of black hole solutions, which possess a regular universal horizon. Whereas, if a three-Ricci curvature squared term is joined in ultraviolet modification, we find a solution with a thunderbolt singularity such that the universal horizon turns out to be a spacelike singularity.

The core of this work is an old and broadly discussed problem concerning electromagnetic radiation in the case of hyperbolic motion. We prove that radiation is nonzero in the lab (Minkowski) frame. Further, we attempt to understand this subject better by using comoving noninertial frames of reference, investigating other types of uniformly accelerated motion, and, finally, using scalar waves instead of pointlike particles as sources of radiation.

In this work we revisit the definition of matter trapping surfaces (MTS) and show how it can be expressed in the so-called dual null formalism developed for trapping horizons (TH). With the aim of unifying both approaches, we construct a $2+2$ threading from the $1+3$ flow in spherical symmetry and thus isolate one preferred spatial direction that allows straightforward translation into a dual null subbasis and deduction of the geometric apparatus that follows. We express the MTS conditions in terms of 2-expansion of the flow, then in purely geometric form of the dual null expansions. The Raychadhuri equations that describe both MTS and TH are written and interpreted using a generalized Tolman-Oppenheimer-Volkov functional. Further using the Misner-Sharp mass and its perfect fluid definition, we relate the spatial 2-expansion to the fluid pressure, density, and acceleration. The Raychaudhuri equations also allow us to define the MTS dynamic condition with first order differentials so the MTS conditions are now shown to be all first order differentials. This unified formalism allows one to realize that the MTS can exist only in normal regions, and so it can exist only between black hole horizons and cosmological horizons. Finally we obtain a relation yielding the sign, on a TH, of the nonvanishing null expansion that determines the nature of the TH from fluid content and flow characteristics. The $2+2$ unified formalism here investigated thus proves a powerful tool to reveal, in the future extensions, more of the very rich and subtle relations between MTS and TH.

Approximating nonlinear dynamics with a truncated perturbative expansion may be accurate for a while, but it, in general, breaks down at a long time scale that is one over the small expansion parameter. There are interesting cases in which such breakdown does not happen. We provide a mathematically general and precise definition of those cases, in which we prove that the validity of truncated theory trivially extends to the long time scale. This enables us to utilize numerical results, which are only obtainable within finite times, to legitimately predict the dynamics when the expansion parameter goes to zero, and thus the long time scale goes to infinity. In particular, this shows that existing noncollapsing solutions in the AdS (in)stability problem persist to the zero-amplitude limit, opposing the conjecture by Dias, Horowitz, Marolf, and Santos that predicts a shrinkage to measure zero [O. J. Dias et al., Classical Quantum Gravity 29, 235019 (2012)]. We also point out why the persistence of collapsing solutions is harder to prove, and how the recent interesting progress by Bizon, Maliborski, and Rostoworowski has not yet proven this [P. Bizon, M. Maliborski, and A. Rostworowski, arXiv:1506.03519].

We show that a contribution due to a second-order amplitude with intermediate $\overline{u}d$ in a loop, which was claimed by Descotes-Genon and Kamenik to dominate the $CP$ asymmetry in $b\to c\ell \nu$, vanishes.

We consider the minimal 3-3-1 model with a heavy scalar sextet and realize, at the tree level, an effective dimension-five interaction that contributes to the mass of the charged leptons. In this case the charged leptons masses arise from a sort of type-II seesawlike mechanism while the neutrino masses are generated by a type-I mechanism. We also show that the parameters giving the correct lepton masses also accommodate the Pontecorvo-Maki-Nakawaga-Sakata matrix. We give the scalar mass spectra of the model and analyze under which conditions the fields in the scalar sextet are heavy even with small or zero vacuum expectation values. We also show the conditions under which it is possible to have a stable (bounded from below) potential and also a global minimum.

We propose a new method of producing a neutrino pair beam that consists of a mixture of neutrinos and antineutrinos of all flavors. The idea is based on a coherent neutrino pair emission from excited ions in circular motion. High energy gamma rays much beyond the kilo-electron-volt range may also be produced by a different choice of excited level.

To be able to achieve their physics goals, future neutrino-oscillation experiments will need to reconstruct the neutrino energy with very high accuracy. In this work, we analyze how the energy reconstruction may be affected by realistic detection capabilities, such as energy resolutions, efficiencies, and thresholds. This allows us to estimate how well the detector performance needs to be determined a priori in order to avoid a sizable bias in the measurement of the relevant oscillation parameters. We compare the kinematic and calorimetric methods of energy reconstruction in the context of two ${\nu }_{\mu }\to {\nu }_{\mu }$ disappearance experiments operating in different energy regimes. For the calorimetric reconstruction method, we find that the detector performance has to be estimated with an $\mathcal{O}(10\%)$ accuracy to avoid a significant bias in the extracted oscillation parameters. On the other hand, in the case of kinematic energy reconstruction, we observe that the results exhibit less sensitivity to an overestimation of the detector capabilities.

We present an analysis of the semi-inclusive decays $B_s\to D_s^{-}X{\ell }^{+}\nu$ and $B_s\to D_s^{*-}X{\ell }^{+}\nu$, where $X$ denotes a final state that may consist of additional hadrons or photons and $\ell$ is an electron or muon. The studied $B_s$ decays are contained in the $121.4{\mathrm{fb}}^{-1}$ $\mathrm{{\rm Y}}(5S)$ data sample collected by the Belle detector at the KEKB asymmetric-energy $e^{+}{e}^{-}$ collider. The branching fractions of the decays are measured to be $\mathcal{B}(B_s\to D_s^{-}X{\ell }^{+}\nu )=[8.2\pm 0.2(\mathrm{stat})\pm 0.6(\mathrm{syst})\pm 1.4(\mathrm{ext})]\%$ and $\mathcal{B}(B_s\to D_s^{*-}X{\ell }^{+}\nu )=[5.4\pm 0.4(\mathrm{stat})\pm 0.4(\mathrm{syst})\pm 0.9(\mathrm{ext})]\%$, where the first two uncertainties are statistical and systematic and the last is due to external parameters. The measurement also provides an estimate of the $B_s^{(*)}{\overline{B}}_s^{(*)}$ production cross section, $\sigma (e^{+}{e}^{-}\to B_s^{(*)}{\overline{B}}_s^{(*)})=[53.8\pm 1.4(\mathrm{stat})\pm 4.0(\mathrm{syst})\pm 3.4(\mathrm{ext})]\mathrm{pb}$, at the center-of-mass energy $\sqrt{s}=10.86\mathrm{GeV}$.

In an analysis of a $2.92{\mathrm{fb}}^{-1}$ data sample taken at 3.773 GeV with the BESIII detector operated at the BEPCII collider, we measure the absolute decay branching fractions $\mathcal{B}(D^0\to K^{-}{e}^{+}{\nu }_e)=(3.505\pm 0.014\pm 0.033)\%$ and $\mathcal{B}(D^0\to {\pi }^{-}{e}^{+}{\nu }_e)=(0.295\pm 0.004\pm 0.003)\%$. From a study of the differential decay rates we obtain the products of hadronic form factor and the magnitude of the Cabibbo-Kobayashi- Maskawa (CKM) matrix element $f_{+}^K(0)|V_{cs}|=0.7172\pm 0.0025\pm 0.0035$ and $f_{+}^{\pi }(0)|V_{cd}|=0.1435\pm 0.0018\pm 0.0009$. Combining these products with the values of $|V_{cs(d)}|$ from the SM constraint fit, we extract the hadronic form factors $f_{+}^K(0)=0.7368\pm 0.0026\pm 0.0036$ and $f_{+}^{\pi }(0)=0.6372\pm 0.0080\pm 0.0044$, and their ratio $f_{+}^{\pi }(0)/f_{+}^K(0)=0.8649\pm 0.0112\pm 0.0073$. These form factors and their ratio are used to test unquenched lattice QCD calculations of the form factors and a light cone sum rule (LCSR) calculation of their ratio. The measured value of $f_{+}^{K(\pi )}(0)|V_{cs(d)}|$ and the lattice QCD value for $f_{+}^{K(\pi )}(0)$ are used to extract values of the CKM matrix elements of $|V_{cs}|=0.9601\pm 0.0033\pm 0.0047\pm 0.0239$ and $|V_{cd}|=0.2155\pm 0.0027\pm 0.0014\pm 0.0094$, where the third errors are due to the uncertainties in lattice QCD calculations of the form factors. Using the LCSR value for $f_{+}^{\pi }(0)/f_{+}^K(0)$, we determine the ratio $|V_{cd}|/|V_{cs}|=0.238\pm 0.004\pm 0.002\pm 0.011$, where the third error is from the uncertainty in the LCSR normalization. In addition, we measure form factor parameters for three different theoretical models that describe the weak hadronic charged currents for these two semileptonic decays. All of these measurements are the most precise to date.

Constraints on the lifetime and width of the Higgs boson are obtained from $H\to ZZ\to 4\ell$ events using data recorded by the CMS experiment during the LHC run 1 with an integrated luminosity of 5.1 and $19.7{\mathrm{fb}}^{-1}$ at a center-of-mass energy of 7 and 8 TeV, respectively. The measurement of the Higgs boson lifetime is derived from its flight distance in the CMS detector with an upper bound of ${\tau }_H<1.9\times {10}^{-13}\mathrm{s}$ at the 95% confidence level (C.L.), corresponding to a lower bound on the width of ${\mathrm{\Gamma }}_H>3.5\times {10}^{-9}\mathrm{MeV}$. The measurement of the width is obtained from an off-shell production technique, generalized to include anomalous couplings of the Higgs boson to two electroweak bosons. From this measurement, a joint constraint is set on the Higgs boson width and a parameter $f_{\mathrm{\Lambda }Q}$ that expresses an anomalous coupling contribution as an on-shell cross-section fraction. The limit on the Higgs boson width is ${\mathrm{\Gamma }}_H<46\mathrm{MeV}$ with $f_{\mathrm{\Lambda }Q}$ unconstrained and ${\mathrm{\Gamma }}_H<26\mathrm{MeV}$ for $f_{\mathrm{\Lambda }Q}=0$ at the 95% C.L. The constraint $f_{\mathrm{\Lambda }Q}<3.8\times {10}^{-3}$ at the 95% C.L. is obtained for the expected standard model Higgs boson width.

We present the $\mathcal{N}=2$ supersymmetric completion of a scalar curvature squared term in a completely gauge independent form. We also elaborate on its component structure.