We investigate the relation between the physical pion pole and screening masses and the mesonic fluctuation scale in low-energy QCD, which relates to the curvature of the mesonic effective potential. This relation is important for the correct relative weight of quantum, thermal and density fluctuations. Hence, it governs the location of phase boundaries as well as the phase structure of QCD. The identification of the correct physics scales is also primarily important for the correct adjustment of the parameters of effective models for low-energy QCD. It is shown that subject to an appropriate definition of the latter, all these scales agree at vanishing temperature, while they deviate from each other at finite temperature.

We study the inclusive hadroproduction of $D^0$, $D^{+}$, $D^{\star +}$, and $D_s^{+}$ mesons at leading order in the parton Reggeization approach endowed with universal fragmentation functions fitted to $e^{+}{e}^{-}$ annihilation data from CERN LEP1. We have described $D$-meson transverse momentum distributions measured in the central region of rapidity by the CDF collaboration at Tevatron ($|y|<1$) and ALICE collaboration at the LHC ($|y|<0.5$) within uncertainties and without free parameters, using Kimber-Martin-Ryskin and Ciafaloni-Catani-Fiorani-Marchesini approaches to obtain unintegrated gluon distribution function in a proton.

Using $53{\mathrm{pb}}^{-1}$ of $e^{+}{e}^{-}$ annihilation data taken at $\sqrt{s}=3.686\mathrm{GeV}$, a comprehensive study has been made of the radiative decays of samples of 5.1 million $J/\psi$ and 24.5 million $\psi (2S)$ into pairs of pseudoscalar mesons, ${\pi }^{+}{\pi }^{-}$, ${\pi }^0{\pi }^0$, $K^{+}{K}^{-}$, $K_S^0{K}_S^0$, and $\eta \eta$. Product branching fractions for the radiative decays of $J/\psi$ and $\psi (2S)$ to scalar resonances $f_0$ (1370, 1500, 1710, 2100, and 2200), and tensor resonances $f_2$ (1270, 1525, and 2230) have been determined, and are discussed in relation to predicted glueballs. For $\psi (2S)$ radiative decays the search for glueballs has been extended to masses between 2.5 GeV and 3.3 GeV.

We establish the direct $d=2$ on-shell bosonization ${\psi }_L(x_{+})=e^{i\xi (x_{+})}$ and ${\psi }_R^{†}(x_{-})=e^{i\xi (x_{-})}$ in path integral formulation by deriving the off-shell relations ${\psi }_L(x){\psi }_R^{†}(x)=\exp [i\xi (x)]$ and ${\psi }_R(x){\psi }_L^{†}(x)=\exp [-i\xi (x)]$. Similarly, the on-shell bosonization of the bosonic commuting spinor, ${\varphi }_L(x_{+})=i{e}^{-i\xi (x_{+})}{\partial }^{+}{e}^{-i\chi (x_{+})}$, ${\varphi }_R^{†}(x_{-})=e^{-i\xi (x_{-})-i\chi (x_{-})}$ and ${\varphi }_R(x_{-})=i{e}^{i\xi (x_{-})}{\partial }^{-}{e}^{+i\chi (x_{-})}$, ${\varphi }_L^{†}(x_{+})=e^{i\xi (x_{+})+i\chi (x_{+})}$, is established in path integral formulation by deriving the off-shell relations ${\varphi }_L(x){\varphi }_R^{†}(x)=i{e}^{-i\xi (x)}{\partial }^{+}{e}^{-i\chi (x)}$ and ${\varphi }_R(x){\varphi }_L^{†}(x)=i{e}^{i\xi (x)}{\partial }^{-}{e}^{i\chi (x)}$.

We present two results in the treatment of self-force of accelerating bodies. If the total force on an extended rigid object is calculated from the change of momentum summed over planes of simultaneity of successive rest frames, then we show that an ideal fluid, moving rigidly, exerts a net force on its boundary that is independent of both pressure and orientation. Under this same definition of total force, we find the electromagnetic self-force for a spherical charged shell of proper radius $R$ accelerating with constant proper acceleration $g$ is $(2e^{2}g/R)[1/12-{\sum }_{n=0}^{\infty }(gR{)}^{2n}((2n-3)(2n-1)(2n+1{)}^2{)}^{-1}]$.

Density perturbations and their dynamic evolution from early to late times can be used for an improved understanding of interesting physical phenomena both in cosmology and in the context of heavy-ion collisions. We discuss the spectrum and bispectrum of these perturbations around a longitudinally expanding fireball after a heavy-ion collision. The time-evolution equations couple the spectrum and bispectrum to each other, as well as to higher-order correlation functions through nonlinear terms. A nontrivial bispectrum is thus always generated, even if absent initially. For initial conditions corresponding to a model of independent sources, we discuss the linear and nonlinear evolution in detail. We show that, if the initial conditions are sufficiently smooth for fluid dynamics to be applicable, the nonlinear effects are relatively small.

We consider the dynamics of a spherically symmetric massless scalar field coupled to general relativity in anti–de Sitter spacetime in the small-amplitude limit. Within the context of our previously developed two time framework (TTF) to study the leading self-gravitating effects, we demonstrate the existence of two new conserved quantities in addition to the known total energy $E$ of the modes: The particle number $N$ and Hamiltonian $H$ of our TTF system. Simultaneous conservation of $E$ and $N$ implies that weakly turbulent processes undergo dual cascades (direct cascade of $E$ and inverse cascade of $N$ or vice versa). This partially explains the observed dynamics of 2-mode initial data. In addition, conservation of $E$ and $N$ limits the region of phase space that can be explored within the TTF approximation and, in particular, rules out equipartition of energy among the modes for general initial data. Finally, we discuss the possible effects of conservation of $N$ and $E$ on late time dynamics.

We apply the recently derived constraintless Clairaut-type formalism to the Cho-Duan-Ge decomposition in $SU(2)$ QCD. We find nontrivial corrections to the physical equations of motion and that the contribution of the topological degrees of freedom is qualitatively different from that found by treating the monopole potential as though it were dynamic. We also find alterations to the field commutation relations that undermine the particle interpretation in the presence of the chromomonopole condensate.

Motivated by the Higgs Inflation scenario, we study static spherically symmetric solutions of the non-Abelian Higgs model coupled nonminimally to gravity. We find solutions for the self-gravitating sphaleron as well as monopolelike solutions and study the impact of the nonminimal coupling on their properties. Finally, we discuss briefly the possibility that these solutions interact gravitationally with starlike objects such as boson stars.

We study the instability of higher-dimensional rotating anti–de Sitter (AdS) black holes through fragmentation. Fragmentation occurs when black holes rotate too fast to sustain their horizon, and then the black holes are broken into small pieces. Using this process, we test the stability of AdS black holes and discover the dynamical upper bounds of the angular momentum and the cosmological constant. We show that AdS black holes can exist stably within limited parameter ranges in the general dimensions. The parameter ranges are obtained numerically in terms of angular momentum and cosmological constant.

It is shown that the extended teleparallel gravitational theories, known as $f(T)$ theories, inherit some on shell local Lorentz invariance associated with the tetrad field defining the spacetime structure. We discuss some enlightening examples, such as Minkowski spacetime and cosmological (Friedmann-Robertson-Walker and Bianchi type I) manifolds. In the first case, we show that the absence of gravity reveals itself as an incapability in the selection of a preferred parallelization at a local level, due to the fact that the infinitesimal local Lorentz subgroup acts as a symmetry group of the frame characterizing Minkowski spacetime. Finite transformations are also discussed in these examples and, contrary to the common lore on the subject, we conclude that the set of tetrads responsible for the parallelization of these manifolds is quite vast and that the remnant group of local Lorentz transformations includes one- and two-dimensional Abelian subgroups of the Lorentz group.

In this paper, we study the effects of high-order operators on the nonrelativistic Lifshitz holography in the framework of the Hořava-Lifshitz (HL) theory of gravity, which naturally contains high-order operators in order for the theory to be power-counting renormalizable, and provides an ideal place for such studies. In particular, we show that the Lifshitz spacetime is still a solution of the full theory of the HL gravity. The effects of the high-order operators on the spacetime itself is simply to shift the Lifshitz dynamical exponent. However, while in the infrared the asymptotic behavior of a (probe) scalar field near the boundary is similar to that studied in the literature, it gets dramatically modified in the UV limit, because of the presence of the high-order operators in this regime. Then, according to the gauge/gravity duality, this in turn affects the two-point correlation functions.

The cosmic background neutrino of temperature 1.9 K affects rates of radiative emission of neutrino pairs (RENP) from metastable excited atoms, since its presence blocks the pair emission by the Pauli exclusion principle. We quantitatively investigate how the Pauli blocking distorts the photon energy spectrum and calculate its sensitivity to cosmic parameters such as the neutrino temperature and its chemical potential. Important quantities for high sensitivities to these parameter measurements are found to be the level spacing of atomic deexcitation and the unknown mass value of the lightest neutrino, in particular, their relationship to one another.

Among the most stringent constraints on the dark matter annihilation cross section are those derived from observations of dwarf galaxies by the Fermi Gamma-Ray Space Telescope. As current (e.g., Dark Energy Survey, DES) and future (Large Synoptic Survey Telescope, LSST) optical imaging surveys discover more of the Milky Way’s ultrafaint satellite galaxies, they may increase Fermi’s sensitivity to dark matter annihilations. In this study, we use a semianalytic model of the Milky Way’s satellite population to predict the characteristics of the dwarfs likely to be discovered by DES and LSST, and project how these discoveries will impact Fermi’s sensitivity to dark matter. While we find that modest improvements are likely, the dwarf galaxies discovered by DES and LSST are unlikely to increase Fermi’s sensitivity by more than a factor of $\sim 2–4$. However, this outlook may be conservative, given that our model underpredicts the number of ultrafaint galaxies with large potential annihilation signals actually discovered in the Sloan Digital Sky Survey. Our simulation-based approach focusing on the Milky Way satellite population demographics complements existing empirically based estimates.

The formalism of stochastic inflation is a powerful tool for analyzing the backreaction of cosmological perturbations, and making precise predictions for inflationary observables. We demonstrate this with the simple $m^2{\varphi }^2$ model of inflation, wherein we obtain an effective field theory for IR modes of the inflaton, which remains coupled to UV modes through a classical noise. We compute slow-roll corrections to the evolution of UV modes (i.e. quantum fluctuations), and track this effect from the UV theory to the IR theory, where it manifests as a correction to the classical noise. We compute the stochastic correction to the spectral index of primordial perturbations, finding a small effect, and discuss models in which this effect can become large. We extend our analysis to tensor modes, and demonstrate that the stochastic approach allows us to recover the standard tensor tilt $n_T$, plus corrections.

We examine the relation between the dynamics of Lemaître–Tolman–Bondi (LTB) dust models (with and without $\mathrm{\Lambda }$) and the dynamics of dust perturbations in two of the more familiar formalisms used in cosmology: the metric based cosmological perturbation theory (CPT) and the covariant gauge invariant (GIC) perturbations. For this purpose we recast the evolution of LTB models in terms of a covariant and gauge invariant formalism of local and nonlocal “exact fluctuations” on a Friedmann–Lemaître–Robertson–Walker (FLRW) background defined by suitable averages of covariant scalars. We examine the properties of these fluctuations, which can be defined for a confined comoving domain or for an asymptotic domain extending to whole time slices. In particular, the nonlocal density fluctuation provides a covariant and precise definition for the notion of the “density contrast.” We show that in their linear regime these LTB exact fluctuations (local and nonlocal) are fully equivalent to the conventional cosmological perturbations in the synchronous-comoving gauge of CPT and to GIC perturbations. As an immediate consequence, we show the time-invariance of the spatial curvature perturbation in a simple form. The present work may provide important theoretical connections between the exact and perturbative (linear or nonlinear) approach to the dynamics of dust sources in general relativity.

The Gaussian kinematic formula (GKF) [R. J. Adler and J. E. Taylor, Random Fields and Geometry (Springer, New York, 2007).] is an extremely powerful tool allowing for explicit analytic predictions of expected values of Minkowski functionals under realistic experimental conditions for cosmological data collections. In this paper, we implement Minkowski functionals on multipoles and needlet components of CMB fields, thus allowing a better control of cosmic variance and extraction of information on both harmonic and real domains; we then exploit the GKF to provide their expected values on spherical maps, in the presence of arbitrary sky masks, and under non-Gaussian circumstances. All our results are validated by numerical experiments, which show a perfect agreement between theoretical predictions and Monte Carlo simulations.

We report a limit on the ultrahigh-energy neutrino flux based on a nondetection of radio pulses from neutrino-initiated particle cascades in the Moon, in observations with the Parkes radio telescope undertaken as part of the LUNASKA project. Because of the improved sensitivity of these observations, which had an effective duration of 127 hours and a frequency range of 1.2–1.5 GHz, this limit extends to lower neutrino energies than those from previous lunar radio experiments, with a detection threshold below ${10}^{20}\mathrm{eV}$. The calculation of our limit allows for the possibility of lunar-origin pulses being misidentified as local radio interference, and includes the effect of small-scale lunar surface roughness. The targeting strategy of the observations also allows us to place a directional limit on the neutrino flux from the nearby radio galaxy Centaurus A.