In this paper, we propose a new approach to probe the quarkonium at the BES-III and the $B$ factories. In the two-photon process, $e^{+}{e}^{-}\to e^{+}{e}^{-}+\mathrm{\text{hadron}}$, the signals of the emitted hadron can be reconstructed through investigating the final leptons $e^{+}{e}^{-}$. Furthermore, by analyzing the distribution of the relative angle between the final $e^{+}$ and $e^{-}$, we can determine the quantum number of the final hadron. For those hadrons that are hard to detect directly, this may provide an effective way. We calculate the cross sections as well as the distributions of the ${\eta }_c(1S,2S)$ and ${\chi }_{cJ}(1P,2P)$ production at tree level and the next-to-leading order QCD radiative corrections. In addition, the cross sections of bottomonium production are considered at tree level. Unfortunately, they are too tiny to be detected.

The Higgs diphoton amplitude from gluon fusion at the LHC interferes with the continuum background induced by quark loops. I investigate the effect of this interference on the position of the diphoton invariant mass peak used to help determine the Higgs mass. At leading order, the interference shifts the peak towards lower mass by an amount of order 150 MeV or more, with the precise value dependent on the methods used to analyze and fit the data.

We discuss a 331 model with three scalar triplets and neutral fermion singlets. We show that in the 331 model with right-handed neutrinos, it is possible to obtain small active neutrino masses via the double and inverse seesaw mechanisms, without the use of scalar sextets or triplets with doubly charged Higgs. Two types of models are discussed. If we have a large Majorana mass matrix for the singlets, the spectrum of neutrinos presents light, heavy, and very heavy masses. The other possibility is a small (zero) Majorana mass matrix, which leads to pseudo-Dirac (Dirac) heavy neutrinos in the TeV scale, in addition to the active light neutrinos.

We report measurements of charmed-hadron $(D^0,D^{*})$ production cross sections at midrapidity in $p+p$ collisions at a center-of-mass energy of 200 GeV by the STAR experiment. Charmed hadrons were reconstructed via the hadronic decays $D^0\to K^{-}{\pi }^{+}$, $D^{*+}\to D^0{\pi }^{+}\to K^{-}{\pi }^{+}{\pi }^{+}$ and their charge conjugates, covering the $p_T$ range of $0.6–2.0$ and $2.0–6.0\mathrm{GeV}/c$ for $D^0$ and $D^{*+}$, respectively. From this analysis, the charm-pair production cross section at midrapidity is $d\sigma /dy{|}_{y=0}^{c\overline{c}}=170\pm 45(\mathrm{stat}{)}_{-59}^{+38}(\mathrm{sys})\mu \mathrm{b}$. The extracted charm-pair cross section is compared to perturbative QCD calculations. The transverse momentum differential cross section is found to be consistent with the upper bound of a fixed-order next-to-leading logarithm calculation.

An inclusive search for the standard model Higgs boson using the four-lepton final state in proton-antiproton collisions produced by the Tevatron at $\sqrt{s}=1.96\mathrm{TeV}$ is conducted. The data are recorded by the CDF II detector and correspond to an integrated luminosity of $9.7{\mathrm{fb}}^{-1}$. Three distinct Higgs decay modes, namely $ZZ$, $WW$, and $\tau \tau$, are simultaneously probed. Nine potential signal events are selected and found to be consistent with the background expectation. We set a 95% credibility limit on the production cross section times the branching ratio and subsequent decay to the four-lepton final state for hypothetical Higgs boson masses between $120\mathrm{GeV}/c^2$ and $300\mathrm{GeV}/c^2$.

The properties of noninteracting $\sigma$ and ${\pi }^0$ mesons are studied at finite temperature, chemical potential, and in the presence of a constant magnetic field. To do this, the energy dispersion relations of these particles, including nontrivial form factors, are derived using a derivative expansion of the effective action of a two-flavor, hot and magnetized Nambu—Jona-Lasinio model up to second order. The temperature dependence of the pole and screening masses as well as the directional refraction indices of magnetized neutral mesons are explored for fixed magnetic fields and chemical potentials. It is shown that, because of the explicit breaking of the Lorentz invariance by the magnetic field, the refraction index and the screening mass of neutral mesons exhibit a certain anisotropy in the transverse and longitudinal directions with respect to the direction of the external magnetic field. In contrast to their longitudinal refraction indices, the transverse indices of the neutral mesons are larger than unity.

After a brief review of the definition and properties of the quantum effective Hamiltonian action, we describe its renormalization flow by a functional renormalization group equation. This equation can be used for a nonperturbative quantization and study of theories with bare Hamiltonians that are not quadratic in the momenta. As an example, the vacuum energy and gap of quantum mechanical models are computed. Extensions of this framework to quantum field theories are discussed. In particular, one possible Lorentz-covariant approach for simple scalar field theories is developed. Fermionic degrees of freedom, being naturally described by a first order formulation, can easily be accommodated in this approach.

In two previous works [K. Dusling, T. Epelbaum, F. Gelis, and R. Venugopalan, Nucl. Phys. A850, 69 (2011); T. Epelbaum and F. Gelis, Nucl. Phys. A872, 210 (2011)], we studied the time evolution of a system of real scalar fields with quartic coupling that shares important features with the color glass condensate description of heavy-ion collisions. Our primary objective was to understand how such a system, when initialized with a nonperturbatively large classical field configuration, reaches thermal equilibrium. An essential goal of these works was to highlight the role played by the quantum fluctuations. However, these studies considered only a system confined within a box of fixed volume. In the present paper, we extend this work to a system that expands in the longitudinal direction, thereby, more closely mimicking a heavy-ion collision. We conclude that the microscopic processes that drive the system toward equilibrium are able to keep up with the expansion of the system; the pressure tensor becomes isotropic despite the anisotropic expansion.

Despite the fact that the integral form of the equations of classical electrodynamics is well known, the same is not true for non-Abelian gauge theories. The aim of the present paper is threefold. First, we present the integral form of the classical Yang-Mills equations in the presence of sources and then use it to solve the long-standing problem of constructing conserved charges, for any field configuration, which are invariant under general gauge transformations and not only under transformations that go to a constant at spatial infinity. The construction is based on concepts in loop spaces and on a generalization of the non-Abelian Stokes theorem for two-form connections. The third goal of the paper is to present the integral form of the self-dual Yang-Mills equations and calculate the conserved charges associated with them. The charges are explicitly evaluated for the cases of monopoles, dyons, instantons and merons, and we show that in many cases those charges must be quantized. Our results are important in the understanding of global properties of non-Abelian gauge theories.

Detecting cosmic rays, in particular, gamma rays, coming from dark matter annihilation or decay is an indirect way to survey the nature of dark matter. In commutative space-time, the annihilation of dark matter candidates (weakly interacting massive particles) to photons proceeds through loop corrections. However, it is possible for weakly interacting massive particles as well as other standard model singlet particles to couple with photons directly in noncommutative space-time. In this paper, we study two-photon annihilation of singlet weakly interacting massive particles in noncommutative space-time. If noncommutative interactions are relevant to the relic abundance, one can exclude some dark matter masses by using Fermi-Lat data.

We study ghosts in multimetric gravity by combining the minisuperspace and the Hamiltonian constraint analysis. We first revisit bimetric gravity and explain why it is ghost-free. Then, we apply our method to trimetric gravity and clarify when the model contains a ghost. More precisely, we prove trimetric gravity generically contains a ghost. However, if we cut the interaction of a pair of metrics, trimetric gravity becomes ghost-free. We further extend the Hamiltonian analysis to general multimetric gravity and calculate the number of ghosts in various models. Thus, we find multimetric gravity with loop type interactions never becomes ghost-free.

Tendex and vortex fields, defined by the eigenvectors and eigenvalues of the electric and magnetic parts of the Weyl curvature tensor, form the basis of a recently developed approach to visualizing spacetime curvature. In particular, this method has been proposed as a tool for interpreting results from numerical binary black hole simulations, providing a deeper insight into the physical processes governing the merger of black holes and the emission of gravitational radiation. Here we apply this approach to approximate but analytical initial data for both single boosted and binary black holes. These perturbative data become exact in the limit of small boost or large binary separation. We hope that these calculations will provide additional insight into the properties of tendex and vortex fields and will form a useful test for future numerical calculations.

The Eisenhart-Duval lift allows embedding nonrelativistic theories into a Lorentzian geometrical setting. In this paper we study the lift from the point of view of the Dirac equation and its hidden symmetries. We show that dimensional reduction of the Dirac equation for the Eisenhart-Duval metric in general gives rise to the nonrelativistic Lévy-Leblond equation in lower dimension. We study in detail in which specific cases the lower dimensional limit is given by the Dirac equation, with scalar and vector flux, and the relation between lift, reduction, and the hidden symmetries of the Dirac equation. While there is a precise correspondence in the case of the lower dimensional massive Dirac equation with no flux, we find that for generic fluxes it is not possible to lift or reduce all solutions and hidden symmetries. As a by-product of this analysis, we construct new Lorentzian metrics with special tensors by lifting Killing-Yano and closed conformal Killing-Yano tensors and describe the general conformal Killing-Yano tensor of the Eisenhart-Duval lift metrics in terms of lower dimensional forms. Last, we show how, by dimensionally reducing the higher dimensional operators of the massless Dirac equation that are associated with shared hidden symmetries, it is possible to recover hidden symmetry operators for the Dirac equation with flux.

When one splits spacetime into space plus time, the Weyl curvature tensor (which equals the Riemann tensor in vacuum) splits into two spatial, symmetric, traceless tensors: the tidal field $\mathcal{E}$, which produces tidal forces, and the frame-drag field $\mathcal{B}$, which produces differential frame dragging. In recent papers, we and colleagues have introduced ways to visualize these two fields: tidal tendex lines (integral curves of the three eigenvector fields of $\mathcal{E}$) and their tendicities (eigenvalues of these eigenvector fields); and the corresponding entities for the frame-drag field: frame-drag vortex lines and their vorticities. These entities fully characterize the vacuum Riemann tensor. In this paper, we compute and depict the tendex and vortex lines, and their tendicities and vorticities, outside the horizons of stationary (Schwarzschild and Kerr) black holes; and we introduce and depict the black holes’ horizon tendicity and vorticity (the normal-normal components of $\mathcal{E}$ and $\mathcal{B}$ on the horizon). For Schwarzschild and Kerr black holes, the horizon tendicity is proportional to the horizon’s intrinsic scalar curvature, and the horizon vorticity is proportional to an extrinsic scalar curvature. We show that, for horizon-penetrating time slices, all these entities ($\mathcal{E}$, $\mathcal{B}$, the tendex lines and vortex lines, the lines’ tendicities and vorticities, and the horizon tendicities and vorticities) are affected only weakly by changes of slicing and changes of spatial coordinates, within those slicing and coordinate choices that are commonly used for black holes. We also explore how the tendex and vortex lines change as the spin of a black hole is increased, and we find, for example, that as a black hole is spun up through a dimensionless spin $a/M=\sqrt{3}/2$, the horizon tendicity at its poles changes sign, and an observer hovering or falling inward there switches from being stretched radially to being squeezed. At this spin, the tendex lines that stick out from the horizon’s poles switch from reaching radially outward toward infinity to emerging from one pole, swinging poloidally around the hole and descending into the other pole.

We study a model of a scalar field minimally coupled to gravity, with a specific potential energy for the scalar field, and include curvature and radiation as two additional parameters. Our goal is to obtain analytically the complete set of configurations of a homogeneous and isotropic universe as a function of time. This leads to a geodesically complete description of the Universe, including the passage through the cosmological singularities, at the classical level. We give all the solutions analytically without any restrictions on the parameter space of the model or initial values of the fields. We find that for generic solutions the Universe goes through a singular (zero-size) bounce by entering a period of antigravity at each big crunch and exiting from it at the following big bang. This happens cyclically again and again without violating the null-energy condition. There is a special subset of geodesically complete nongeneric solutions which perform zero-size bounces without ever entering the antigravity regime in all cycles. For these, initial values of the fields are synchronized and quantized but the parameters of the model are not restricted. There is also a subset of spatial curvature-induced solutions that have finite-size bounces in the gravity regime and never enter the antigravity phase. These exist only within a small continuous domain of parameter space without fine-tuning the initial conditions. To obtain these results, we identified 25 regions of a 6-parameter space in which the complete set of analytic solutions are explicitly obtained.

During inflation in the early universe, the Higgs field continuously acquires long-wave quantum fluctuations. They accumulate to yield a nonvanishing value with an exponentially large correlation length. We study consequences of such Higgs condensations to show that, in inflation models where the Universe is reheated through gravitational particle production at the transition to the kination regime, they not only contribute to reheat the Universe but also act as a curvaton. Unfortunately, however, for parameters of the Standard Model Higgs field, this curvaton produces density fluctuations too large, so the inflation models followed by a long kination regime are ruled out.

We study the production of prompt photons in strongly coupled out-of-equilibrium super Yang-Mills plasma using the AdS/CFT correspondence. Our goal is to determine the photon emission spectrum at different stages of a thermalization process, which is modeled via the gravitational collapse of a thin spherical shell in ${\mathrm{AdS}}_5$ space. Particular emphasis is placed on the limit of large frequencies, which we are able to treat analytically.

Conversions and semiannihilations of dark matter (DM) particles in addition to the standard DM annihilations are considered in a three-component DM system. We find that the relic abundance of DM can be very sensitive to these nonstandard DM annihilation processes, which has been recently found for two-component DM systems. To consider a concrete model of a three-component DM system, we extend the radiative seesaw model of Ma by adding a Majorana fermion $\chi$ and a real scalar boson $\varphi$, to obtain a $Z_2\times Z_2^{\prime }$ DM stabilizing symmetry, where we assume that the DM particles are the inert Higgs boson, $\chi$ and $\varphi$. It is shown how the allowed parameter space, obtained previously in the absence of $\chi$ and $\varphi$, changes. The semiannihilation process in this model produces monochromatic neutrinos. The observation rate of these monochromatic neutrinos from the Sun at IceCube is estimated. Observations of high-energy monochromatic neutrinos from the Sun may indicate a multicomponent DM system.

The nonrelativistic annihilation of Majorana dark matter in the Sun to a pair of light fermions is chirality suppressed. Annihilation to 3-body final states ${\ell }^{+}{f}^{-}V$, where $V=W$, $Z$, $\gamma$, and $\ell$ and $f$ are light fermions (that may be the same), becomes dominant since bremsstrahlung relaxes the chirality suppression. We evaluate the neutrino spectra at the source, including spin and helicity dependent effects, and assess the detectability of each significant bremsstrahlung channel at IceCube/DeepCore. We also show how to combine the sensitivities to the dark matter—nucleon scattering cross section in individual channels, since typically several channels contribute in models.