We present a study of the $D^{*}\rho$ system made by using the method of QCD sum rules to determine the mass of possible resonances generated in the same system. Using isospin and spin projectors, we investigate the different configurations and obtain evidences for three $D^{*}$ mesons with isospin $I=1/2$, spin $S=0$, 1, 2 and with masses $2500\pm 67$, $2523\pm 60$, and $2439\pm 119\mathrm{MeV}$, respectively. The last state can be associated with $D_2^{*}(2460)$ (spin 2) listed by the Particle Data Group, while one of the first two might be related to $D^{*}(2640)$, with unknown spin parity. In the case of $I=3/2$ we also find evidences of three states with spin 0, 1, and 2, respectively, with masses $2467\pm 82$, $2420\pm 128$, and $2550\pm 56\mathrm{MeV}$. The results for the sector $I=1/2$ and $S=0$, 1, 2, are intriguingly similar to a previous study of the $D^{*}\rho$ system based on effective field theories, supporting in this way a molecular picture for the resonances $D^{*}(2640)$ and $D_2^{*}(2460)$, while the results for $I=3/2$ hint towards the existence of exotic mesons since a multiquark configuration is required to get the quantum numbers of the states found.

We introduce a hybrid variable flavor number scheme for heavy flavors, denoted H-VFNS, which incorporates the advantages of both the traditional variable flavor number scheme as well as the fixed flavor number scheme (FFNS). By including an explicit $N_F$ dependence in both the parton distribution functions (PDFs) and the strong coupling constant ${\alpha }_S$, we generate coexisting sets of PDFs and ${\alpha }_S$ for $N_F=\{3,4,5,6\}$ at any scale $\mu$ that are related analytically by the $\overline{\mathrm{MS}}$ matching conditions. The H-VFNS resums the heavy quark contributions and provides the freedom to choose the optimal $N_F$ for each particular data set. Thus, we can fit selected HERA data in a FFNS framework, while retaining the benefits of the VFNS to analyze LHC data at high scales. We illustrate how such a fit can be implemented for the case of both HERA and LHC data.

We investigate the production of the weak bosons $W^{+}$, $W^{-}$ and $Z$ at the LHC as a function of their rapidity, reconstructed experimentally from their leptonic decay. We show that the measurements provide a powerful tool for constraining the parton distribution functions, as was already the case for the lower energy $p\overline{p}$ collider data. We study the charge asymmetry determining the $u$ and $d$ distribution functions using the reconstructed $W^{+}$, $W^{-}$ rapidities. We also show how the ratio of the $W$ and $Z$ boson rapidity distributions directly probes the charm quark distribution function of the proton.

The $e^{+}{e}^{-}\to p\overline{p}$ cross section and the proton magnetic form factor have been measured in the center-of-mass energy range from 3.0 to 6.5 GeV using the initial-state radiation technique with an undetected photon. This is the first measurement of the form factor at energies higher than 4.5 GeV. The analysis is based on $469{\mathrm{fb}}^{-1}$ of integrated luminosity collected with the BABAR detector at the PEP-II collider at $e^{+}{e}^{-}$ center-of-mass energies near 10.6 GeV. The branching fractions for the decays $J/\psi \to p\overline{p}$ and $\psi (2S)\to p\overline{p}$ have also been measured.

In this paper we examine a small but detailed test of the emergent gravity picture with explicit solutions in gravity and gauge theory. We first derive symplectic $U(1)$ gauge fields starting from the Eguchi-Hanson metric in four-dimensional Euclidean gravity. The result precisely reproduces the $U(1)$ gauge fields of the Nekrasov-Schwarz instanton previously derived from the top-down approach. In order to clarify the role of noncommutative spacetime, we take the Braden-Nekrasov $U(1)$ instanton defined in ordinary commutative spacetime and derive a corresponding gravitational metric. We show that the Kähler manifold determined by the Braden-Nekrasov instanton exhibits a spacetime singularity while the Nekrasov-Schwarz instanton gives rise to a regular geometry—the Eguchi-Hanson space. This result implies that the noncommutativity of spacetime plays an important role for the resolution of spacetime singularities in general relativity. We also discuss how the topological invariants associated with noncommutative $U(1)$ instantons are related to those of emergent four-dimensional Riemannian manifolds according to the emergent gravity picture.

We construct a fermion system in a multi-kink-antikink soliton background, and present in an explicit form all its trapped configurations (bound state solutions) as well as scattering states. This is achieved by exploiting an exotic $N=4$ centrally extended nonlinear supersymmetry of completely isospectral pairs of reflectionless Schrödinger systems with potentials to be $n$-soliton solutions for the Korteweg–de Vries equation. The obtained reflectionless Dirac system with a position-dependent mass is shown to possess its own exotic nonlinear supersymmetry associated with the matrix Lax-Novikov operator being a Darboux-dressed momentum. In the process, we get an algebraic recursive representation for the multi-kink-antikink backgrounds, and establish their relation to the the modified Korteweg–de Vries equation. We also indicate how the results can be related to the physics of self-consistent condensates based on the Bogoliubov–de Gennes equations.

The effect of mass and energy loading on the efficiency at which energy can be extracted magnetically from a Kerr black hole is explored, using a semianalytic, ideal magnetohydrodynamics model that incorporates plasma injection on magnetic field lines. We find a critical load below which the specific energy of the plasma inflowing into the black hole is negative, and above which it is positive, and identify two types of flows with distinct properties; at subcritical loads a magnetic outflow is launched from the ergosphere, owing to extraction of the black hole spin energy, as originally proposed by Blandford and Znajek. At supercritical loads the structure of the flow depends on the details of the injection process. In cases where the injected plasma is relativistically hot, a pressure-driven, double transmagnetosonic flow is launched from a stagnation point located outside the ergosphere, between the inner and outer light cylinders. Some fraction of the energy deposited in the magnetosphere is then absorbed by the black hole and the rest emerges at infinity in the form of a relativistic outflow. When the injected plasma is cold an outflow may not form at all. We discuss the implications of our results to gamma ray bursts and active galactic nuclei.

In this paper, we consider the solutions of Einstein gravity in the presence of a generalized Maxwell theory, namely power Maxwell invariant. First, we investigate the analogy of nonlinear charged black hole solutions with the Van der Waals liquid–gas system in the extended phase space where the cosmological constant appear as pressure. Then, we plot isotherm $P-V$ diagram and study the thermodynamics of AdS black hole in the (grand canonical) canonical ensemble in which (potential) charge is fixed at infinity. Interestingly, we find the phase transition occurs in the both of canonical and grand canonical ensembles in contrast to Reissner-Nordström black hole in Maxwell theory which only admits canonical ensemble phase transition. Moreover, we calculate the critical exponents and find their values are the same as those in mean field theory. Besides, we find in the grand canonical ensembles universal ratio $\frac{P_c{v}_c}{T_c}$ is independent of spacetime dimensions.

The study of compact binary inspirals and mergers with gravitational wave observatories amounts to optimizing a theoretical description of the data to best reproduce the true detector output. While most of the research effort in gravitational wave data modeling focuses on the gravitational waveforms themselves, here we will begin to improve our model of the instrument noise by introducing parameters that allow us to determine the background instrumental power spectrum while simultaneously characterizing the astrophysical signal. We use data from the fifth LIGO science run and simulated gravitational wave signals to demonstrate how the introduction of noise parameters results in the resilience of the signal characterization to variations in an initial estimation of the noise power spectral density. We find substantial improvement in the consistency of Bayes factor calculations when we are able to marginalize over uncertainty in the instrument noise level.

The Hamiltonian constraint is the key element of the canonical formulation of loop quantum gravity (LQG) coding its dynamics. In Ashtekar-Barbero variables it naturally splits into the so-called Euclidean and Lorentzian parts. However, due to the high complexity of this operator, only the matrix elements of the Euclidean part have been considered so far. Here we evaluate the action of the full constraint, including the Lorentzian part. The computation requires heavy use of $SU(2)$ recoupling theory and several tricky identities among $n\mathrm{\text{−}}j$ symbols are used to find the final result: these identities, together with the graphical calculus used to derive them, also simplify the Euclidean constraint and are of general interest in LQG computations.

We discuss conformal issues of pure and extended teleparallel gravity. In particular, we present formulations of conformal transformation in teleparallel gravity. Furthermore, we propose conformal scalar and gauge field theories in teleparallel gravity and study conformal torsion gravity. We explicitly demonstrate that a power-law acceleration (including the $\Lambda \mathrm{CDM}$ universe) as well as the de Sitter expansion of the Universe can be realized in extended teleparallel gravity with a conformal scalar field, and that pure teleparallel gravity with a conformal scalar field can lead to the $\Lambda \mathrm{CDM}$ model. It is also shown that the de Sitter solution can exist in conformal torsion gravity.

A general scheme of constructing scalar-tensor equivalents to modified gravitational actions are studied using the algebra of exterior differential forms and the first order formalism that allows an independent connection and coframe. By introducing appropriate constraints on the connection, pseudo-Riemannian cases as well as non-Riemannian cases are discussed for various gravitational models. The issue of the dynamical degree of freedom for the resulting scalar fields is discussed at the level of the field equations. Explicit scalar-tensor equivalents for gravitational models based on $f(R)$ models, the quadratic curvature Lagrangians and the models involving the gradients of the scalar curvature are presented. In particular, explicit scalar-tensor equivalence for gravitational Lagrangians popular in some cosmological models are constructed.

We study the inflation with a Gauss-Bonnet term which is nonminimally coupled to a Dirac-Born-Infeld (DBI) field. We study the spectrum of primordial perturbations in this setup in detail. The non-Gaussianity of perturbations is considered and the amplitude of the non-Gaussianity is studied in both the equilateral and orthogonal configurations. By adopting various functions of the DBI field, the inflaton potential, and the Gauss-Bonnet coupling term, we test the model with recent observational data and find some constraints on the Gauss-Bonnet coupling parameter.

We study, both analytically and numerically, an Abelian Higgs vortex in the spacetime of a stationary axisymmetric black hole being the solution of the low-energy limit of the heterotic string theory, acting as hair on the black hole background. Taking into account the gravitational backreaction of the vortex, we show that its influence is far more subtle than causing only a conical defect. As a consequence of its existence, we find that the ergosphere is shifted, and the event horizon angular velocity is affected by its presence. Numerical simulations reveal the strong dependence of the vortex behavior on the black hole charge and mass of the Higgs boson. For large masses of the Higgs boson and large values of the charge, the black hole is always pierced by an Abelian Higgs vortex, while small values of the charge and Higgs boson mass lead to the expulsion of the Higgs field.

We consider conserved currents in an interacting network of one-dimensional objects (or strings). Singular currents localized on a single string are considered in general, and a formal procedure for coarse graining over many strings is developed. This procedure is applied to strings described by the Nambu-Goto action, such as cosmic strings. In addition to conserved currents corresponding to the energy-momentum tensor, we consider an antisymmetric tensor of conserved currents related to the string tangent vector. Under the assumption of local equilibrium we derive a complete set of hydrodynamic equations for strings.

In this work we study the evolution of matter-density perturbations for an arbitrary $\Lambda (t)$ model and specialize our analysis to the particular phenomenological law $\Lambda ={\Lambda }_0+3\beta H^2$. We study the evolution of the cosmic star formation rate in this particular dark energy scenario and, by constraining the $\beta$ parameter using both the age of the Universe and the cosmic star formation rate curve, we show that it leads to a reasonable physical model for $\beta \lesssim 0.1$.

Using the geometry of a double-layered torus, we investigate the deconfining phase transition of pure SU(3) lattice gauge theory by Markov chain Monte Carlo simulations. In one layer, called “outside,” the temperature is set below the deconfining temperature and in the other, called “inside,” it is iterated to a pseudotransition temperature. Lattice sizes are chosen in a range suggested by the physical volumes achieved in relativistic heavy ion collisions, and both temperatures are kept close enough to stay in the SU(3) scaling region, which is required for approaching a quantum continuum limit. Properties of the transition are studied as a function of the volume for three outside temperatures. When compared with infinite volume extrapolations, small volume corrections of the deconfining temperature and width compete with those found by including quarks. Effective finite-size scaling exponents of the specific heat and Polyakov loop susceptibilities are also calculated.

We use QCD light-cone sum rules with holographic anti–de Sitter/chromodynamics distribution amplitudes for the $\rho$ meson to predict the form factors that govern the leading amplitudes of the rare radiative $B\to \rho \gamma$ decay and the semileptonic decay $B\to \rho l\nu$. We test the Isgur-Wise relation between the radiative and semileptonic form factors. We also compute the total width (in units of $|V_{ub}{|}^2$) for the semileptonic decay $B\to \rho l\nu$ as well as ratios of partial decay widths which are independent of $|V_{ub}|$.

At large number of colors, $N_c$ quarks in baryons are in a mean field of definite space and flavor symmetry. We write down the general Lorentz and flavor structure of the mean field, and derive the Dirac equation for quarks in that field. The resulting baryon resonances exhibit a hierarchy of scales: the crude mass is $\mathcal{O}(N_c)$, the intrinsic quark excitations are $\mathcal{O}(1)$, and each intrinsic quark state entails a finite band of collective excitations that are split as $\mathcal{O}(1/N_c)$. We build a (new) theory of these collective excitations, where the full dynamics is represented by only a few constants. In a limiting (but unrealistic) case when the mean field is spherically and flavor symmetric, our classification of resonances reduces to the SU(6) classification of the old nonrelativistic quark model. Although in the real world $N_c$ is only three, we obtain a good accordance with the observed resonance spectrum up to 2 GeV.

Medium-baseline reactor experiments (Double Chooz, Daya Bay and RENO) provide a unique opportunity to test the presence of light sterile neutrinos. We analyze the data of these experiments in the search of sterile neutrinos and also test the robustness of ${\theta }_{13}$ determination in the presence of sterile neutrinos. We show that existence of a light sterile neutrino state improves the fit to these data moderately. We also show that the measured value of ${\theta }_{13}$ by these experiments is reliable even in the presence of sterile neutrinos, and the reliability owes significantly to the Daya Bay and RENO data. From the combined analysis of the data of these experiments, we constrain the mixing of a sterile neutrino with $\Delta m_{41}^2\sim ({10}^{-3}–{10}^{-1}){\mathrm{eV}}^2$ to ${sin}^{2}2{\theta }_{14}\lesssim 0.1$ at 95% C.L.