We review the current status of the minimal nonsupersymmetric $SO(10)$ grand unified theory and perform a detailed next-to-leading-order analysis of the gauge unification and proton lifetime constraints on the part of its parameter space supporting a ZeV-scale color sextet scalar. This, together with a TeV-scale color octet studied in detail in a preceding work, represents one of the two minimally fine-tuned settings compatible with all the relevant consistency and phenomenology limits. Both these scenarios can be extensively tested at the future megaton-scale proton-decay facilities. On top of that, the light octet solution can be accessible in the TeV-scale collider searches.

The chiral thermodynamics of charmed mesons is formulated at a finite temperature within a ($2+1+1$)–flavored effective Lagrangian incorporating heavy quark symmetry. The charmed-meson mean fields act as an extra source which breaks the chiral symmetry explicitly. This leads to effective interactions between the light and heavy-light mesons, which intrinsically depend on temperature. Effective masses of the scalar and pseudoscalar charmed mesons tend to approach each other as temperature increases, so that the splitting between the chiral partners is reduced. These chiral splittings are shown to be less sensitive to the light quark flavors, attributed to the underlying heavy quark symmetry. Consequently, chiral symmetry restoration is more manifest for the strange charmed mesons than for the strange light mesons. The effective masses are also compared with the results in the one-loop chiral perturbation theory. A substantial difference is found at a relatively low temperature, $T\sim f_{\pi }$.

The $W^{+}{W}^{-}$ cross section has remained one of the most consistently discrepant channels compared to Standard Model (SM) predictions at the LHC, measured by both ATLAS and CMS at 7 and 8 TeV. Developing a better modeling of this channel is crucial to understanding properties of the Higgs and potential new physics. In this paper we investigate the effects of next-to-next-to-leading-log transverse momentum resummation in measuring the $W^{+}{W}^{-}$ cross section. In the formalism we employ, transverse momentum resummation does not change the total inclusive cross section but gives a more accurate prediction for the $p_T$ distribution of the diboson system. By reweighting the $p_T$ distribution of events produced by Monte Carlo generators, we find a systematic shift that decreases the experimental discrepancy with the SM prediction by approximately 3%–7% depending on the Monte Carlo generator and parton shower used. The primary effect comes from the jet-veto cut used by both experiments. We comment on the connections to jet-veto resummation and other methods the experiments can use to test this effect. We also discuss the correlation of resummation effects in this channel with other diboson channels. Ultimately $p_T$ resummation improves the agreement between the SM and experimental measurements for most generators but does not account for the measured $\sim 20\%$ difference with the SM, and further investigations into this channel are needed.

We extend a recent approach to describe the $B^0$ and $B_s^0$ decays into $J/\psi$ $f_0(500)$ and $J/\psi$ $f_0(980)$, relating it to the $B^0$ and $B_s^0$ decays into $J/\psi$ and a vector meson, $\varphi$, $\rho$, $K^{*}$. In addition, the $B^0$ and $B_s^0$ decays into $J/\psi$ and $\kappa (800)$ are evaluated and compared to the $K^{*}$ vector production. The rates obtained are in agreement with the available experiment while predictions are made for the $J/\psi$ plus $\kappa (800)$ decay.

An explicit form of the pion scalar form factor ${\mathrm{\Gamma }}_{\pi }(t)$ is constructed by using its phase representation and a correct description of the S-wave isoscalar $\pi \pi$ phase shift ${\delta }_0^0(t)$ data by the parametrization of $\tan {\delta }_0^0(t)$ in the absolute valued pion c.m. three-momentum $q=[(t-4m_{\pi }^2)/4{]}^{1/2}$. This parametrization has been found starting from fully general considerations. Then a calculation of the corresponding integral in the framework of the theory of residua provides ${\mathrm{\Gamma }}_{\pi }(t)$ in the form of a rational function with one zero and four poles in the $q$ variable. Investigations of the latter poles demonstrate that two of them, to be conjugate according to the imaginary axis in the $q$ plane, clearly correspond to complex conjugate $f_0(500)$ meson poles on the second Riemann sheet in a momentum transfer squared $t$ variable. Another pair of poles, also conjugate according to the imaginary axis in the $q$ plane, can be identified with two complex conjugate poles on the second Riemann sheet in the $t$ variable, corresponding to the $f_0(980)$ meson.

In this paper we calculate the full one-loop finite volume corrections to the quantities $⟨x{⟩}_{u\pm d}$ within the framework of two-flavor baryon chiral perturbation theory. For the isovector case, we show estimates of these effects for the leading one-loop corrections based on fits carried out in previously published works.

We present results for mass effects coming from secondary radiation of heavy quark pairs related to gluon splitting in the thrust distribution for $e^{+}{e}^{-}$ collisions. The results are given in the dijet limit where the hard interaction scale and the scales related to collinear and soft radiation are widely separated. We account for the corresponding fixed-order corrections at $\mathcal{O}({\alpha }_s^2)$ and the summation of all logarithmic terms related to the hard, collinear, and soft scales as well as the quark mass at ${\mathrm{N}}^3\mathrm{LL}$ order. We also remove the $\mathcal{O}({\mathrm{\Lambda }}_{\mathrm{QCD}})$ renormalon in the partonic soft function, leading to an infrared evolution equation with a matching condition related to the massive quark threshold. The quark mass can be arbitrary, ranging from the infinitely heavy case, where decoupling takes place, down to the massless limit, where the results smoothly merge into the well-known predictions for massless quarks. Our results are formulated in the framework of factorization theorems for $e^{+}{e}^{-}$ dijet production and provide universal threshold corrections for the renormalization group evolution of the hard current, the jet, and the soft functions at the scale where the massive quarks are integrated out. The results represent a first explicit realization of a variable-flavor-number scheme for final-state jets along the lines of the well-known flavor-number-dependent evolution of the strong coupling ${\alpha }_s$ and the parton distribution functions.

The razor approach to search for $R$–parity conserving supersymmetric particles is described in detail. Two analyses are considered: an inclusive search for new heavy particle pairs decaying to final states with at least two jets and missing transverse energy, and a dedicated search for final states with at least one jet originating from a bottom quark. For both the inclusive study and the study requiring a bottom-quark jet, the data are examined in exclusive final states corresponding to all-hadronic, single-lepton, and dilepton events. The study is based on the data set of proton-proton collisions at $\sqrt{s}=7\mathrm{TeV}$ collected with the CMS detector at the LHC in 2011, corresponding to an integrated luminosity of $4.7{\mathrm{fb}}^{-1}$. The study consists of a shape analysis performed in the plane of two kinematic variables, denoted $M_R$ and $R^2$, that correspond to the mass and transverse energy flow, respectively, of pair-produced, heavy, new-physics particles. The data are found to be compatible with the background model, defined by studying event simulations and data control samples. Exclusion limits for squark and gluino production are derived in the context of the constrained minimal supersymmetric standard model (CMSSM) and also for simplified-model spectra (SMS). Within the CMSSM parameter space considered, squark and gluino masses up to 1350 GeV are excluded at 95% confidence level, depending on the model parameters. For SMS scenarios, the direct production of pairs of top or bottom squarks is excluded for masses as high as 400 GeV.

If two particles moving towards a black hole collide near the horizon, their energy in the center-of-mass frame can grow unbounded. This is the so-called Bañados-Silk-West effect. Previously, it was shown that in the $3+1$ space-time, this effect has a universal nature. We show that for a wide class of many-dimensional black holes (including, say, the Myers-Perry black hole), this is also true. The suggested analysis is general and does not require special properties of the metric like separability of variables for geodesics, etc.

A supersymmetric solution to type II supergravity is constructed by superposing two hyper-Kählers with torsion metrics. The solution is given by a Kähler with torsion metric with $SU(3)$ holonomy. The metric is embedded into a heterotic solution obeying the Strominger system, together with a Yang–Mills instanton obtained by the standard embedding. T dualities lead to an $SO(6)$ instanton describing a symmetry breaking from $E_8$ to $SO(10)$. The compactification by taking a periodic array yields a supersymmetric domain wall solution of heterotic supergravity.

It is shown that the gray-body factor for a one-dimensional elongated Bose-Einstein condensate (BEC) acoustic black hole with one horizon does not vanish in the low-frequency ($\omega \to 0$) limit. This implies that the analog Hawking radiation is dominated by the emission of an infinite number ($\frac{1}{\omega }$) of soft phonons in contrast with the case of a Schwarzschild black hole where the gray-body factor vanishes as $\omega \to 0$ and the spectrum is not dominated by low-energy particles. The infrared behaviors of certain correlation functions are also discussed.

We perform a covariant constraint analysis of massive gravity valid for its entire parameter space, demonstrating that the model generically propagates 5 degrees of freedom; this is also verified by a new and streamlined Hamiltonian description. The constraint’s covariant expression permits computation of the model’s caustics. Although new features such as the dynamical Riemann tensor appear in the characteristic matrix, the model still exhibits the pathologies uncovered in earlier work: superluminality and likely acausalities.

We present here a simple construction of a wavelet system for the three-dimensional ball, which we label radial 3D needlets. The construction envisages a data collection environment in which an observer located at the center of the ball is surrounded by concentric spheres with the same pixelization at different radial distances, for any given resolution. The system is then obtained by weighting the projector operator built on the corresponding set of eigenfunctions and performing a discretization step which turns out to be computationally very convenient. The resulting wavelets can be shown to have very good localization properties in the real and harmonic domain; their implementation is computationally very convenient, and they allow for exact reconstruction as they form a tight frame system. Our theoretical results are supported by an extensive numerical analysis.

Recently, BICEP2 measurements of the cosmic microwave background (CMB) $B$-mode polarization at degree angular scales has indicated the presence of tensor modes with a high tensor-to-scalar ratio of $r=0.2$ when assuming nearly scale-invariant tensor and scalar spectra, although the signal may be contaminated by dust emission, as implied by recent Planck polarization data. This result is in conflict with the Planck best-fit lambda cold dark model with $r<0.11$. Because the inflaton has to interact with other fields to convert its potential energy into radiation to reheat the Universe, the interacting inflaton may result in a suppression of the scalar spectrum at large scales. This suppression has been used to explain the observed low quadrupole in the CMB anisotropy. In this paper, we show that a combination of the tensor modes measured by BICEP2 and the large-scale suppressed scalar modes contributes to the CMB anisotropy in such a way that the resultant CMB anisotropy and polarization power spectra are consistent with both Planck and BICEP2 data. We also project our findings to cases in which $r$ may become reduced in future CMB polarization measurements.

We study the viscosity spectral function of a holographic $2+1$ dimensional fluid with Schrödinger symmetry. The model is based on a twisted compactification of ${\mathrm{AdS}}_5\times S_5$. We numerically compute the spectral function of the stress tensor correlator for all frequencies, and analytically study the limits of high and low frequency. We compute the shear viscosity, the viscous relaxation time, and the quasinormal mode spectrum in the shear channel. We find a number of unexpected results: The high frequency behavior is governed by a fractional $1/3$ power law, the viscous relaxation time is negative, and the quasinormal mode spectrum in the shear channel is not doubled.

The effect of the anomalous magnetic moment of quarks on thermodynamic properties of the chiral condensate is studied, using a two-flavor Nambu–Jona-Lasinio model at finite temperature $T$, chemical potential $\mu$, and in the presence of a uniform magnetic field $eB$. To this purpose, the Schwinger linear-in-$B$ ansatz for the anomalous magnetic moment of quarks is considered in terms of the nonperturbative Bohr magneton. In a two-dimensional flavor space, it leads to the correction ${\widehat{T}}_{Sch}=\widehat{\kappa }\widehat{Q}eB$ in the energy dispersion relation of quarks. Here, $\widehat{Q}$ is the quark charge matrix. We consider three different sets for $\widehat{\kappa }$, and numerically determine the dependence of the constituent quark mass on $T,\mu$, and $eB$ for fixed $\widehat{\kappa }$. By exploring the complete phase portrait of this model in $T-\mu$, $\mu -eB$, and $T-eB$ phase spaces for various fixed $eB$, $T$, $\mu$, and $\widehat{\kappa }$, we observe that inverse magnetic catalysis occurs for large enough $\widehat{\kappa }$. Moreover, in the regime of weak magnetic fields, the phenomenon of reentrance of chiral symmetry broken and restored phases occurs for $T\text{−}$, $\mu \text{−}$, and $eB$-dependent $\widehat{\kappa }$.

A simple expression for calculating the interparticle potential energy concerning $D$-dimensional electromagnetic models is obtained via Feynman path integral. This prescription converts the hard task of computing this potential into a trivial algebraic exercise. Since this method is equivalent to that based on the merging of quantum mechanics (to leading order, i.e., in the first Born approximation) with the nonrelativistic limit of quantum field theory, and keeping in mind that the latter relies basically on the computation of the nonrelativistic Feynman amplitude (${\mathcal{M}}_{\mathrm{NR}}$), a trivial expression for calculating ${\mathcal{M}}_{\mathrm{NR}}$ is obtained from the alluded prescription as an added bonus. To test the efficacy and simplicity of the method, $D$-dimensional interparticle potential energy is found for a well-known extension of the standard model in which the massless electrodynamics $\mathrm{U}(1{)}_{\mathrm{QED}}$ is coupled to a hidden sector $\mathrm{U}(1{)}_{\mathrm{h}}$, as well as Lee-Wick electrodynamics.

Inspired by the Wald-Kodama entropy $S=A/(4G_{\text{eff}})$ where $A$ is the horizon area and $G_{\mathrm{eff}}$ is the effective gravitational coupling strength in modified gravity with field equation $R_{\mu \nu }-R{g}_{\mu \nu }/2=8\pi G_{\mathrm{eff}}{T}_{\mu \nu }^{(\text{eff})}$, we develop a unified and compact formulation in which the Friedmann equations can be derived from thermodynamics of the Universe. The Hawking and Misner-Sharp masses are generalized by replacing Newton’s constant $G$ with $G_{\mathrm{eff}}$, and the unified first law of equilibrium thermodynamics is supplemented by a nonequilibrium energy dissipation term $\mathcal{E}$ which arises from the revised continuity equation of the perfect-fluid effective matter content and is related to the evolution of $G_{\mathrm{eff}}$. By identifying the mass as the total internal energy, the unified first law for the interior and its smooth transit to the apparent horizon yield both Friedmann equations, while the nonequilibrium Clausius relation with entropy production for an isochoric process provides an alternative derivation on the horizon. We also analyze the equilibrium situation $G_{\mathrm{eff}}=G=\text{constant}$, provide a viability test of the generalized geometric masses, and discuss the continuity/conservation equation. Finally, the general formulation is applied to the Friedmann-Robertson-Walker cosmology of minimally coupled $f(R)$, generalized Brans-Dicke, scalar-tensor-chameleon, quadratic, $f(R,\mathcal{G})$ generalized Gauss-Bonnet and dynamical Chern-Simons gravity. In these theories we also analyze the $f(R)$-Brans-Dicke equivalence, find that the chameleon effect causes extra energy dissipation and entropy production, geometrically reconstruct the mass ${\rho }_{m}V$ for the physical matter content, and show the self-inconsistency of $f(R,\mathcal{G})$ gravity in problems involving $G_{\mathrm{eff}}$.

We discuss the dynamics of extended test bodies for a large class of scalar-tensor theories of gravitation. A covariant multipolar Mathisson—Papapetrou—Dixon type of approach is used to derive the equations of motion in a systematic way for both Jordan and Einstein formulations of these theories. The results obtained provide the framework to experimentally test scalar-tensor theories by means of extended test bodies.