We provide details of the study of $\psi (3770)$ non-$D\overline{D}$ decays into $VP$, where $V$ and $P$ denote light vector meson and pseudoscalar meson, respectively. We find that the electromagnetic interaction plays little role in these processes, while the strong interaction dominates. The strong interaction can be separated into two parts, i.e., the short-distance part probing the wave function at origin and the long-distance part reflecting the soft gluon exchanged dynamics. The long-distance part is thus described by the intermediate charmed meson loops. We show that the transition of $\psi (3770)\to VP$ can be related to $\psi (3686)\to VP$ such that the parameters in our model can be constrained by comparing the different parts in $\psi (3770)\to VP$ to those in $\psi (3686)\to VP$. Our quantitative results confirm the findings of Zhang et al. [Phys. Rev. Lett. 102, 172001 (2009)] that the OZI-rule-evading long-distance strong interaction via the intermediate meson loops plays an important role in $\psi (3770)$ decays and could be a key towards a full understanding of the mysterious $\psi (3770)$ non-$D\overline{D}$ decay mechanism.

The analysis of the recent charged-current neutrino-nucleus scattering cross sections measured by the ArgoNeuT Collaboration requires relativistic theoretical descriptions also accounting for the role of final-state interactions. In this work, we evaluate differential neutrino-nucleus cross sections with the relativistic Green’s function model, where final-state interactions are described in the inclusive scattering consistently with the exclusive scattering using a complex optical potential. The sensitivity to the parametrization adopted for the phenomenological optical potential is discussed. The predictions of the relativistic Green’s function model are compared with the results of different descriptions of final-state interactions.

We argue that a generic instability afflicts vacua that arise in theories whose moduli space has large dimension. Specifically, by studying theories with multiple scalar fields we provide numerical evidence that for a generic local minimum of the potential the usual semiclassical bubble nucleation rate, $\Gamma =A{e}^{-B}$, increases rapidly as function of the number of fields in the theory. As a consequence, the fraction of vacua with tunneling rates low enough to maintain metastability appears to fall exponentially as a function of the moduli space dimension. We discuss possible implications for the landscape of string theory. Notably, if our results prove applicable to string theory, the landscape of metastable vacua may not contain sufficient diversity to offer a natural explanation of dark energy.

The autocorrelation of density fluctuations for thermally relativistic fluids is formulated on the basis of the relativistic Navier-Stokes-Fourier equation under the static equilibrium state. The autocorrelation of density fluctuations for thermally relativistic fluids, obtained theoretically, is compared with the autocorrelation of density fluctuations for thermally relativistic fluids, calculated using the stochastic relativistic Boltzmann equation on the basis of the direct simulation Monte Carlo method. The theoretical result of the autocorrelation of density fluctuations for thermally relativistic fluids on the basis of the relativistic Navier-Stokes-Fourier equation gives good agreement with the numerical result of the autocorrelation of density fluctuations for thermally relativistic fluids in the lowest wave number, because we calculated the autocorrelation of density fluctuations for thermally relativistic fluids under the transition regime between the rarefied and continuum regimes.

Using a representative set of parameters, we numerically calculate the low-energy Lagrangian on the world sheet of the Abrikosov-Nielsen-Olesen string in a model in which it acquires rotational (quasi)moduli. The bulk model is deformed by a spin-orbit interaction, generating a number of “entangled” terms on the string world sheet.

By means of simple models in a flat spacetime manifold we examine some of the issues that arise when quantizing interacting quantum fields in multimetric backgrounds. In particular we investigate the maintenance of a causal structure in the models. In this context we introduce and explain the relevance of an interpolating metric that is a superposition of the individual metrics in the models. We study the renormalization of a model with quartic interactions and elucidate the structure of the renormalization group and its implications for Lorentz symmetry breakdown.

We study particle acceleration in the strong gravitational field of a rotating black hole in a Randall-Sundrum brane with a nonvanishing effective cosmological constant. The strong dependence of the collision energy of the accelerating particles on the parameters, such as the radius of the innermost stable circular orbits $r_{\mathrm{ISCO}}$ and the value of the dimensionless parameter $\xi =(r_{\mathrm{ISCO}}-r_{\mathrm{h}})/r_{\mathrm{h}}$ of the particles moving around the rotating black hole in a Randall-Sundrum brane space-time, has been found. It is shown that the contribution of the parameter $\xi$ decreases the rate of acceleration and imposes a limitation on the energy of the accelerating particles, preventing them from having an infinite value. Finally, we study the ejected particles’ energy from a collision of two accelerating particles around a rotating black hole in the brane.

Motivated by the search for new observables in nonperturbative quantum gravity, we consider causal dynamical triangulations in $2+1$ dimensions with the spatial topology of a torus. This system is of particular interest, because one can study not only the global scale factor, but also global shape variables in the presence of arbitrary quantum fluctuations of the geometry. Our initial investigation focuses on the dynamics of the scale factor and uncovers a qualitatively new behavior, which leads us to investigate a novel type of boundary conditions for the path integral. Comparing large-scale features of the emergent quantum geometry in numerical simulations with a classical minisuperspace formulation, we find partial agreement. By measuring the correlation matrix of volume fluctuations we succeed in reconstructing the effective action for the scale factor directly from the simulation data. Apart from setting the stage for the analysis of shape dynamics on the torus, the new setup highlights the role of nontrivial boundaries and topology.

Quantization prescriptions that realize generalized uncertainty relations are motivated by quantum gravity arguments that incorporate a fundamental length scale. We apply two such methods, polymer and deformed Heisenberg quantization, to scalar field theory in Fourier space. These alternative quantizations modify the oscillator spectrum for each mode, which in turn affects the blackbody distribution. We find that for a large class of modifications, the equation of state relating pressure $P$ and energy density $\rho$ interpolates between $P=\rho /3$ at low $T$ and $P=2\rho /3$ at high $T$, where $T$ is the temperature. Furthermore, the Stefan-Boltzman law gets modified from $\rho \propto T^4$ to $\rho \propto T^{5/2}$ at high temperature. This suggests an effective reduction to 2.5 spacetime dimensions at high energy.

We present new constraints on the relativistic neutrino effective number $N_{\mathrm{eff}}$ and on the cosmic microwave background power spectrum lensing amplitude $A_{\mathrm{L}}$ from the recent Planck 2013 data release. Including observations of the cosmic microwave background large angular scale polarization from the Wilkinson microwave anisotropy probe (WMAP) satellite, we obtain the bounds $N_{\mathrm{eff}}=3.71\pm 0.40$ and $A_{\mathrm{L}}=1.25\pm 0.13$ at 68% C.L. We discuss the agreement of these results with the previous constraints obtained from the Atacama Cosmology Telescope (ACT) and the South Pole Telescope (SPT). Considering the constraints on the cosmological parameters, we found a very good agreement with the previous $\mathrm{WMAP}+\mathrm{SPT}$ analysis but a tension with the $\mathrm{WMAP}+\mathrm{ACT}$ results, with the only exception of the lensing amplitude.

In this paper we provide a prescription for obtaining a small non-Gaussianity and the observed dipole asymmetry in the cosmic microwave background radiation. The observations inevitably lead to multifield inflationary dynamics, where each field can create positive or negative large non-Gaussianity, resulting in a fine cancellation but with an observable imprint on the hemispherical asymmetry. We discuss this possibility within a simple slow-roll scenario and find that it is hard to explain the observed dipole asymmetry. We briefly discuss some speculative scenarios where one can explain dipole asymmetry.

The Planck and WMAP9 satellites, as well as the ATACAMA and South Pole telescopes, have recently presented results on the angular power spectrum of the comic microwave background. Data tentatively point to the existence of an extra radiation component in the early Universe. Here, we show that this extra component can be mimicked by ordinary weakly interacting massive particle dark matter particles whose majority is cold, but with a small fraction being nonthermally produced in a relativistic state. We present a few example theories where this scenario is explicitly realized and explore the relevant parameter space consistent with big bang nucleosynthesis, cosmic microwave background, and structure formation bounds.

In this paper, we quantify the ability of a future measurement of the Sandage-Loeb test signal from the Cosmic Dynamic Experiment-like spectrograph to constrain some popular modified gravity theories, including the Dvali-Gabadadze-Porrati braneworld scenario, $f(R)$ modified gravity, and $f(T)$ gravity theory. We find that the Sandage-Loeb test measurements are able to markedly break degeneracies between model parameters and thus greatly improve cosmological constraints for all concerned modified gravity theories when combined with the latest observations of the cosmic microwave background shift parameter. However, they yield almost the same degeneracy directions between model parameters as that from the distance ratio data derived from the latest observations of the cosmic microwave background and baryon acoustic oscillations. Moreover, for $f(R)$ modified gravity, the Sandage-Loeb test could provide completely different bounded regions in model-parameter space as compared to cosmic microwave background and baryon acoustic oscillations and thus supplement strong complementary constraints.

In 1676 Olaus Rømer presented the first observational evidence for a finite light velocity $c_{\mathrm{em}}$. He formed his estimate by attributing the periodically varying discrepancy between the observed and expected occultation times of the Galilean satellite Io by its planetary host Jupiter to the time it takes light to cross Earth’s orbital diameter. Given a stable celestial clock that can be observed in gravitational waves the same principle can be used to measure the propagation speed $c_{\mathrm{gw}}$ of gravitational radiation. Space-based “LISA”-like detectors will, and terrestrial LIGO-like detectors may, observe such clocks and thus be capable of directly measuring the propagation velocity of gravitational waves. In the case of space-based detectors the clocks will be galactic close white-dwarf binary systems; in the case of terrestrial detectors, the most likely candidate clock is the periodic gravitational radiation from a rapidly rotating nonaxisymmetric neutron star. Here we evaluate the accuracy that may be expected of such a Rømer-type measurement of $c_{\mathrm{gw}}$ by foreseeable future space-based and terrestrial detectors. For space-based, LISA-like detectors, periodic sources are plentiful: by the end of the first year of scientific operations a LISA-like detector will have measured $c_{\mathrm{gw}}$ to better than a part in a thousand. Periodic sources may not be accessible in terrestrial detectors available to us in the foreseeable future; however, if such a source is detected then with a year of observations we could measure $c_{\mathrm{gw}}$ to better than a part in a million.

We perform the first general relativistic force-free simulations of neutron star magnetospheres in orbit about spinning and nonspinning black holes. We find promising precursor electromagnetic emission: typical Poynting luminosities at, e.g., an orbital separation of $r=6.6R_{\mathrm{NS}}$ are $L_{\mathrm{EM}}\sim 6\times {10}^{42}(B_{\mathrm{NS},\mathrm{p}}/{10}^{13}\mathrm{G}{)}^2({\mathrm{M}}_{\mathrm{NS}}/1.4{\mathrm{M}}_{\odot }{)}^2\mathrm{erg}/\mathrm{s}$. The Poynting flux peaks within a broad beam of $\sim 40°$ in the azimuthal direction and within $\sim 60°$ from the orbital plane, establishing a possible lighthouse effect. Our calculations, though preliminary, preview more detailed simulations of these systems that we plan to perform in the future.

The monodromy transform and corresponding integral equation method described here give rise to a general systematic approach for solving integrable reductions of field equations for gravity coupled bosonic dynamics in string gravity and supergravity as well as for pure vacuum gravity in four and higher dimensions. For physically different types of fields in space-times of $D\ge 4$ dimensions with $d=D-2$ commuting isometries—stationary fields with spatial symmetries, interacting waves or evolution of partially inhomogeneous cosmological models—the string gravity equations govern the dynamics of interacting gravitational, dilaton, antisymmetric tensor, and any number $n\ge 0$ of Abelian vector gauge fields (all depending only on two coordinates). The equivalent spectral problem constructed earlier allows one to parametrize the entire infinite-dimensional space of (normalized) local solutions of these equations by two pairs of arbitrary coordinate-independent holomorphic $d\times d$- and $d\times n$- matrix functions $\{{\mathbf{u}}_{\pm }(w),{\mathbf{v}}_{\pm }(w)\}$ of a spectral parameter $w$ which constitute a complete set of monodromy data for a normalized fundamental solution of this spectral problem. The “direct” and “inverse” problems of such monodromy transform—calculating the monodromy data for any local solution and constructing the field configurations for any chosen monodromy data—always admit unique solutions. We construct the linear singular integral equations which solve this inverse problem. For any rational and analytically matched [i.e. ${\mathbf{u}}_{+}(w)\equiv {\mathbf{u}}_{-}(w)$ and ${\mathbf{v}}_{+}(w)\equiv {\mathbf{v}}_{-}(w)$] monodromy data the solution of these integral equations and corresponding solution for string gravity equations can be found explicitly. Simple reductions of the space of monodromy data leads to the similar constructions for solving of other integrable symmetry reduced gravity models, e.g. 5D minimal supergravity or vacuum gravity in $D\ge 4$ dimensions.

We propose a simple model of baryogenesis comprised of the standard model coupled to a singlet $X$ via higher dimension operators $\mathcal{O}$. In the early universe, $X$ is thermalized by $\mathcal{O}$ mediated scattering processes before it decouples relativistically and evolves into a sizable fraction of the total energy density. Eventually, $X$ decays via $\mathcal{O}$ in an out of equilibrium, baryon number and $CP$ violating process that releases entropy and achieves baryogenesis for a broad range of parameters. The decay can also produce a primordial abundance of dark matter. Because $X$ may be as light as a TeV, viable regions of parameter space lie within reach of experimental probes of $n\mathrm{\text{−}}\overline{n}$ oscillation, flavor physics, and proton decay.

Perhaps the most important question in particle physics today is whether the boson with mass near 125 GeV discovered at the Large Hadron Collider (LHC) is the Higgs Boson of the Standard Model. Since a particularly important property of the Standard Model Higgs is its role in unitarizing $W_{\mathrm{L}}{W}_{\mathrm{L}}$ scattering, we study the ability of the LHC to probe this process in the case of same-sign $W$ pair production. We find that the use of the matrix element method increases the significance with which the Higgs sector can be probed in this channel. In particular, it allows one to distinguish between a light and heavy Standard Model Higgs in this channel alone with a high degree of significance, as well as to set important limits in the parameter space of the two-Higgs doublet model and the strongly interacting light Higgs model with less than $200{\mathrm{fb}}^{-1}$ at the 14 TeV LHC, thus providing crucial information about the putative Higgs boson’s role in electroweak symmetry breaking.

In order for neutralino dark matter to avoid being overproduced in the early Universe, these particles must annihilate (or coannihilate) rather efficiently. Neutralinos with sufficiently large couplings to annihilate at such high a rate (such as those resulting from gaugino-Higgsino mixing, as in “well-tempered” or “focus point” scenarios), however, have become increasingly disfavored by the null results of XENON100 and other direct detection experiments. One of the few remaining ways that neutralinos could potentially evade such constraints is if they annihilate through a resonance, as can occur if $2m_{{\chi }^0}$ falls within about $\sim 10\%$ of either $m_{A/H}$, $m_h$, or $m_Z$. If no signal is observed from upcoming direct detection experiments, the degree to which such a resonance must be tuned will increase significantly. In this paper, we quantify the degree to which such a resonance must be tuned in order to evade current and projected constraints from direct detection experiments. Assuming a future rate of progress among direct detection experiments that is similar to that obtained over the past decade, we project that within 7 years the light Higgs and $Z$ pole regions will be entirely closed, while the remaining parameter space near the $A/H$ resonance will require that $2m_{{\chi }^0}$ be matched to the central value (near $m_A$) to within less than 4%. At this rate of progress, it will be a little over a decade before multiton direct detection experiments will be able to close the remaining, highly tuned, regions of the $A/H$ resonance parameter space.

The susceptibilities of the real and imaginary parts, as well as of the modulus, of the Polyakov loop, are computed in SU(3) lattice gauge theory. We show that the ratios of these susceptibilities are excellent probes of the deconfinement transition, independent of the renormalization of the Polyakov loop and only weakly dependent on the system size. The ratios are almost temperature independent above and below the transition and exhibit a discontinuity at the transition temperature. This characteristic behavior can be understood in terms of the global ${\mathcal{Z}}_3$ symmetry of the Yang-Mills Lagrangian and the general properties of the Polyakov loop probability distribution.