The $B^{-}\to D^{+}{K}^{-}{\pi }^{-}$ decay is observed in a data sample corresponding to $3.0{\mathrm{fb}}^{-1}$ of $pp$ collision data recorded by the LHCb experiment during 2011 and 2012. Its branching fraction is measured to be $\mathcal{B}(B^{-}\to D^{+}{K}^{-}{\pi }^{-})=(7.31\pm 0.19\pm 0.22\pm 0.39)\times 10^{-5}$ where the uncertainties are statistical, systematic and from the branching fraction of the normalization channel $B^{-}\to D^{+}{\pi }^{-}{\pi }^{-}$, respectively. An amplitude analysis of the resonant structure of the $B^{-}\to D^{+}{K}^{-}{\pi }^{-}$ decay is used to measure the contributions from quasi-two-body $B^{-}\to D_0^{*}(2400{)}^0{K}^{-}$, $B^{-}\to D_2^{*}(2460{)}^0{K}^{-}$, and $B^{-}\to D_J^{*}(2760{)}^0{K}^{-}$ decays, as well as from nonresonant sources. The $D_J^{*}(2760{)}^0$ resonance is determined to have spin 1.

Three-mode parametric instability has been predicted in advanced gravitational wave detectors. Here we present the first observation of this phenomenon in a large scale suspended optical cavity designed to be comparable to those of advanced gravitational wave detectors. Our results show that previous modeling assumptions that transverse optical modes are stable in frequency except for frequency drifts on a thermal deformation time scale is unlikely to be valid for suspended mass optical cavities. We demonstrate that mirror figure errors cause a dependence of transverse mode offset frequency on spot position. Combined with low-frequency residual motion of suspended mirrors, this leads to transverse mode frequency modulation which suppresses the effective parametric gain. We show that this gain suppression mechanism can be enhanced by laser spot dithering or fast thermal modulation. Using Advanced LIGO test-mass data and thermal modeling, we show that gain suppression factors of 10–20 could be achieved for individual modes, sufficient to greatly ameliorate the parametric instability problem.

Many-body systems with a conserved $U(1)$ current in $(2+1)$ dimensions may be probed by weakly gauging this current and studying correlation functions of magnetic monopole operators in the resulting dynamical gauge theory. We study such monopole correlations in holographic liquids with fundamental flavor, where the monopole operator is dual to a magnetically charged particle in the bulk. In charge-gapped phases, the monopole operator is expected to condense. We show that this condensation is holographically dual to the capping off of the bulk flavor brane and compute the monopole condensate. We argue that from the lower-dimensional point of view, this may be understood as a simple example of confinement of a gauge field in the bulk. In a compressible finite-density phase, we present a novel calculation of the monopole correlation in space and time: the correlation is power law in time but Gaussian in space due to interaction with the background charge density.

In this article a particular classical, relativistic Lagrangian based on the isotropic fermion sector of the Lorentz-violating (minimal) Standard Model extension is considered. The motion of the associated classical particle in an external electromagnetic field is studied, and the evolution of its spin, which is introduced by hand, is investigated. It is shown that the particle travels along trajectories that are scaled versions of the standard ones. Furthermore there is no spin precession due to Lorentz violation, but the rate is modified at which the longitudinal and transverse spin components transform into each other. This demonstrates that it is practical to consider classical physics within such an isotropic Lorentz-violating framework and it opens the pathway to study a curved background in that context.

We analyze a model for the Higgs sector with two scalar doublets and a ${\mathbb{Z}}_2$ symmetry that is manifest in the Yukawa sector but broken in the potential. Thus, one of the doublets breaks the electroweak symmetry and has tree-level Yukawa couplings to fermions, whereas the other doublet has no vacuum expectation value and no tree-level couplings to fermions. Since the ${\mathbb{Z}}_2$ parity is broken the two doublets can mix, which leads to a distinct and novel phenomenology. This stealth doublet model can be seen as a generalization of the inert doublet model with a broken ${\mathbb{Z}}_2$ symmetry. We outline the model and present constraints from theory, electroweak precision tests, and collider searches, including the recent observation of a Higgs boson at the LHC. The charged scalar $H^{\pm }$ and the $CP$-odd scalar $A$ couple to fermions at one-loop level. We compute the decays of $H^{\pm }$ and $A$ and in particular the one-loop decays $A\to f\overline{f}$, $H^{\pm }\to f{\overline{f}}^{\prime }$, $H^{\pm }\to W^{\pm }Z$ and $H^{\pm }\to W^{\pm }\gamma$. We also describe how to calculate and renormalize such processes in our model. We find that if one of $H^{\pm }$ or $A$ is the lightest scalar, $H^{\pm }\to W^{\pm }\gamma$ or $A\to b\overline{b}$ are typically their respective dominating decay channels. Otherwise, the dominating decays of $H^{\pm }$ and $A$ are into a scalar and a vector. Due to the absence of tree-level fermion couplings for $H^{\pm }$ and $A$, we consider pair production and associated production with vector bosons and scalars at the LHC. If the parameter space of the model that favors $H^{\pm }\to W^{\pm }\gamma$ is realized in Nature, we estimate that there could be a considerable amount of such events in the present LHC data.

We present an improved determination of the strange sea distribution in the nucleon with constraints coming from the recent charm production data in neutrino-nucleon deep-inelastic scattering by the NOMAD and CHORUS experiments and from charged current inclusive deep-inelastic scattering at HERA. We demonstrate that the results are consistent with the data from the ATLAS and the CMS experiments on the associated production of $W^{\pm }$-bosons with $c$-quarks. We also discuss issues related to the recent strange sea determination by the ATLAS experiment using LHC collider data.

Soft leptogenesis is a mechanism which generates the matter-antimatter asymmetry of the Universe via the out-of-equilibrium decays of heavy sneutrinos in which soft supersymmetry breaking terms play two important roles: they provide the required $CP$ violation and give rise to the mass splitting between otherwise degenerate sneutrino mass eigenstates within a single generation. This mechanism is interesting because it can be successful at the lower temperature regime $T\lesssim 10^9\mathrm{GeV}$ in which the conflict with the overproduction of gravitinos can possibly be avoided. In earlier works, the leading $CP$ violation is found to be nonzero only if finite temperature effects are included. By considering generic soft trilinear couplings, we find two interesting consequences: (1) the leading $CP$ violation can be nonzero even at zero temperature realizing nonthermal $CP$ violation, and (2) the $CP$ violation is sufficient even far away from the resonant regime allowing soft supersymmetry breaking parameters to assume natural values at around the TeV scale. We discuss phenomenological constraints on such scenarios and conclude that the contributions to charged lepton flavor violating processes are close to the sensitivities of present and future experiments.

We investigate the possibility to test a simple theory for spontaneous baryon number violation at the Large Hadron Collider. In this context the baryon number is a local gauge symmetry spontaneously broken at the low scale through the Brout-Englert-Higgs mechanism. This theory predicts the existence of a leptophobic neutral gauge boson and a fermionic dark matter candidate with baryon number. We study the gauge boson and Higgs decays, and explore the connection between collider signatures and constraints coming from dark matter experiments. We point out an upper bound on the symmetry breaking scale using the relic density constraints, which tells us that this model can be tested or ruled out at current or future collider experiments.

A new approach to expanding the “Stückelbergized” fiducial metric in a covariant manner is developed. The idea is to consider the curved 4-dimensional space as a codimension-one hypersurface embedded in a 5-dimensional Minkowski bulk, in which the 5-dimensional Goldstone modes can be defined as usual. After solving one constraint among the five 5-dimensional Goldstone modes and projecting to the 4-dimensional hypersurface, we are able to express the Stückelbergized fiducial metric in terms of the 4-dimensional Goldstone modes as well as 4-dimensional curvature quantities. We also compared the results with expressions gotten using the Riemann normal coordinates in Gao et al. [Phys. Rev. D 90, 124073 (2014)] and find that, after a simple field redefinition, results gotten in two approaches exactly coincide.

We show that a recent solution published by Cabrera-Munguia et al. is physically inconsistent since the quantity $\sigma$ it involves does not have a correct limit $R\to \infty$.

In this work we present a new class of braneworld models, where the superpotential function may be decomposed in an specific form, which allows considerable simplifications in the field equations. We exemplify the method with two specific models that are extended versions of superpotentials already considered in the literature. As one can see in the examples, the braneworld scenarios obtained here present very interesting features, such as a split-brane mechanism and an asymmetric warp factor shape, which is essential for addressing the hierarchy problem in the context of thick-brane scenarios.

Topologically stable non-Abelian sine-Gordon solitons have been found recently in the $U(N)$ chiral Lagrangian and a $U(N)$ gauge theory with two $N$ by $N$ complex scalar fields coupled to each other. We construct the effective theory on a non-Abelian sine-Gordon soliton that is a nonlinear sigma model with the target space $\mathbb{R}\times \mathbb{C}{P}^{N-1}$. We then show that $\mathbb{C}{P}^{N-1}$ lumps on it represent $SU(N)$ Skyrmions in the bulk point of view, providing a physical realization of the rational map ansatz for Skyrmions of the translational (Donaldson) type. We find therefore that Skyrmions can exist stably without the Skyrme term.

It is sometimes argued that observation of tensor modes from inflation would provide the first evidence for quantum gravity. However, in the usual inflationary formalism, also the scalar modes involve quantized metric perturbations. We consider the issue in a semiclassical setup in which only matter is quantized, and spacetime is classical. We assume that the state collapses on a spacelike hypersurface and find that the spectrum of scalar perturbations depends on the hypersurface. For reasonable choices, we can recover the usual inflationary predictions for scalar perturbations in minimally coupled single-field models. In models where nonminimal coupling to gravity is important and the field value is sub-Planckian, we do not get a nearly scale-invariant spectrum of scalar perturbations. As gravitational waves are only produced at second order, the tensor-to-scalar ratio is negligible. We conclude that detection of inflationary gravitational waves would indeed be needed to have observational evidence of quantization of gravity.

It is commonly believed that the fidelity of quantum teleportation using localized quantum objects with one party or both accelerated in vacuum would be degraded due to the heat up by the Unruh effect. In this paper, we point out that the Unruh effect is not the whole story in accounting for all the relativistic effects in quantum teleportation. First, there could be degradation of fidelity by a common field environment even when both quantum objects are in inertial motion. Second, relativistic effects entering the description of the dynamics, such as frame dependence, time dilation, and Doppler shift, already existent in inertial motion, can compete with or even overwhelm the effect due to uniform acceleration in a quantum field. We show it is not true that larger acceleration of an object would necessarily lead to a faster degradation of fidelity. These claims are based on four cases of quantum teleportation we studied using two Unruh–DeWitt detectors coupled via a common quantum field initially in the Minkowski vacuum. We find the quantum entanglement evaluated around the light cone, rather than the conventional ones evaluated on the Minkowski time slices, is the necessary condition for the averaged fidelity of quantum teleportation beating the classical one. These results are useful as a guide to making judicious choices of states and parameter ranges and estimation of the efficiency of quantum teleportation in relativistic quantum systems under environmental influences.

We present a calculation of the rate of information release from a Schwarzschild black hole (BH). We have recently extended Hawking’s theory of BH evaporation to account for quantum fluctuations of the background geometry, as well as for backreaction and time-dependence effects. Our main result has been a two-point function matrix for the radiation that consists of Hawking’s thermal matrix plus off-diagonal corrections that are initially small and become more important as the evaporation proceeds. Here, we show that, if the phases and amplitudes of the radiation matrix are recorded over the lifetime of the BH, then the radiation purifies in a continuous way. It is also shown that our framework achieves a rate of information release from a semiclassical BH that is faster than that predicted by Page on the basis of generic unitarity arguments. When the phases of the radiation matrix are not tracked, we show that it could perhaps purify, but only parametrically close to the end of the BH evaporation. Our main technical tool in the quantitative treatment of this purification is the purity of the radiation matrix and, its inverse, the participation ratio. These can be related to the Renyi entropy of the density matrix of the emitted radiation.

Inspired by a Chern-Simons description of $2+1$-dimensional gravity coupled to point particles we propose a new Lagrangian of a multiparticle system living in $\kappa$-Minkowski/$\kappa$-Poincaré spacetime. We derive the dynamics of interacting particles with $\kappa$-momentum space, alternative to the one proposed in the “principle of relative locality” literature. The model that we obtain takes account of the nonlocal topological interactions between the particles, so that the effective multiparticle action is not a sum of their free actions. In this construction the locality of particle processes is naturally implemented, even for distant observers. In particular a particle process is characterized by a local deformed energy-momentum conservation law. The spacetime transformations are generated by total charges/generators for the composite particle system, and leave unaffected the locality of individual particle processes.

$f(R)$ gravity is one of the simplest generalizations of general relativity, which may explain the accelerated cosmic expansion without introducing a cosmological constant. Transformed into the Einstein frame, a new scalar degree of freedom appears and it couples with matter fields. In order for $f(R)$ theories to pass the local tests of general relativity, it has been known that the chameleon mechanism with a so-called thin-shell solution must operate. If the thin-shell constraint is applied to a cosmological situation, it has been claimed that the equation-of-state parameter of dark energy $w$ must be extremely close to $-1$. We argue this is due to the incorrect use of the Poisson equation, which is valid only in the static case. By solving the correct Klein-Gordon equation perturbatively, we show that a thin-shell solution exists even if $w$ deviates appreciably from $-1$.

We provide a detailed quantitative description of singular inflation. Its close analogy with finite-time future singularity which is associated to dark energy era is described. Calling and classifying the singularities of such inflation as finite time cosmological singularities we investigate their occurrence, with special emphasis on the Type IV singularity. The study is performed in the context of a general noncanonical scalar-tensor theory. In addition, the impact of finite time singularities on the slow-roll parameters is also investigated. Particularly, we study three cases, in which the singularity occurs during the inflationary era, at the end, and also we study the case that the singularity occurs much more later than inflation ends. Using the obtained slow-roll parameters, for each case, we calculate explicitly the spectral index of primordial curvature perturbations $n_s$, the associated running of the spectral index $a_s$ and of the scalar-to-tensor ratio $r$ and compare the resulting values to the Planck and BICEP2 data. As we demonstrate, in some cases corresponding to the Type IV singularity, there might be the possibility of agreement with the observational data, when the singularity occurs at the end, or after inflation. However, absolute concordance of all observational indices is not achieved. On the contrary, if the singularity occurs during the inflationary era, this is catastrophic for the theory, since the observational indices become divergent. We also show how a Type IV singularity may be consistently accommodated in the Universe’s late time evolution, and we study the behavior of the effective equation of state. In addition, we investigate when inflation ends classically, in the context of our scalar-tensor model. Finally, we investigate which $F(R)$ gravity can generate the Type IV singularity, with special emphasis on the behavior near the finite time singularity.

The linear perturbation theory of inhomogeneous reionization (LPTR) has been developed as an analytical tool for predicting the global ionized fraction and large-scale power spectrum of ionized density fluctuations during reionization. In the original formulation of the LPTR, the ionization balance and radiative transfer equations are linearized and solved in Fourier space. However, the LPTR’s approximation to the full solution of the radiative transfer equation is not straightforward to interpret, since the latter is most intuitively conceptualized in position space. To bridge the gap between the LPTR and the language of numerical radiative transfer, we present a new, equivalent, position-space formulation of the LPTR that clarifies the approximations it makes and facilitates its interpretation. We offer a comparison between the LPTR and the excursion-set model of reionization (ESMR), and demonstrate the built-in capability of the LPTR to explore a wide range of reionization scenarios, and to go beyond the ESMR in exploring scenarios involving X-rays.

The measurement of frequency shifts for light beams exchanged between two test masses nearly in free fall is at the heart of gravitational-wave detection. It is envisaged that the derivative of the frequency shift is in fact limited by differential forces acting on those test masses. We calculate the derivative of the frequency shift with a fully covariant, gauge-independent and coordinate-free method. This method is general and does not require a congruence of nearby beams’ null geodesics as done in previous work. We show that the derivative of the parallel transport is the only means by which gravitational effects shows up in the frequency shift. This contribution is given as an integral of the Riemann tensor—the only physical observable of curvature—along the beam’s geodesic. The remaining contributions are the difference of velocities, the difference of nongravitational forces, and finally fictitious forces, either locally at the test masses or nonlocally integrated along the beam’s geodesic. As an application relevant to gravitational-wave detection, we work out the frequency shift in the local Lorentz frame of nearby geodesics.