We study the motion of neutral test particles in the gravitational field of two charged black holes described by the extreme Reissner-Nordstrøm dihole metric where the masses and charges of the black holes are chosen such that the gravitational attraction is compensated by the electrostatic repulsion. We investigate circular orbits in the equatorial plane between the two black holes with equal masses as well as the case of circular orbits outside this symmetry plane. We show that the first case reduces to an effective two-body problem with a behavior similar to a system described by the Reissner-Nordstrøm spacetime. The main focus is directed to the second case with circular orbits outside the equatorial plane.

We investigate the strong form factors and coupling constants of vertices containing the strange charmed mesons $D_{s0}^{*}$, $D_s$, $D_s^{*}$, and $D_{s1}$ with the vector mesons $\varphi$ and $J/\psi$ in the framework of the three point QCD sum rules. Taking into account the nonperturbative part contributions of the correlation functions, the condensate terms of dimension 3, 4 and 5 related to the contributions of the quark-quark, gluon-gluon, and quark-gluon condensate, respectively, are evaluated. The present work can give considerable information about the hadronic processes involving the strange charmed mesons.

We discuss phenomenology of the radiative seesaw model in which spontaneous breaking of the $\mathrm{U}(1{)}_{\mathrm{B}-\mathrm{L}}$ gauge symmetry at the TeV scale gives the common origin for masses of neutrinos and dark matter [S. Kanemura, T. Nabeshima, and H. Sugiyama, Phys. Rev. D 85, 033004 (2012).]. In this model, the stability of dark matter is realized by the global $\mathrm{U}(1{)}_{\mathrm{DM}}$ symmetry which arises by the $\mathrm{B}-\mathrm{L}$ charge assignment. Right-handed neutrinos obtain TeV scale Majorana masses at the tree level. Dirac masses of neutrinos are generated via one-loop diagrams. Consequently, tiny neutrino masses are generated at the two-loop level by the seesaw mechanism. This model gives characteristic predictions, such as light decayable right-handed neutrinos, Dirac fermion dark matter, and an extra heavy vector boson. These new particles would be accessible at collider experiments because their masses are at the TeV scale. The $\mathrm{U}(1{)}_{\mathrm{B}-\mathrm{L}}$ vector boson may be found at the LHC, while the other new particles could only be tested at future linear colliders. We find that the dark matter can be observed at a linear collider with $\sqrt{s}=500\mathrm{GeV}$ and that light right-handed neutrinos can also be probed with $\sqrt{s}=1\mathrm{TeV}$.

We determine the contribution to the $S$ and $T$ parameters coming from extensions of the standard model featuring a light nonstandard-like Higgs particle. We neatly separate, using the Landau gauge, the contribution from the purely nonstandard Higgs sector, from the one due to the interplay of this sector with the standard model. If the nonstandard Higgs sector derives from a new type of strong dynamics, the formalism allows one to precisely link the intrinsic underlying contribution with the experimentally relevant parameters.

We investigate the spectrum of supersymmetric grand unification models based on the gauge groups $SU(5)$, $SO(10)$ and $E_6$, paying particular attention to the first and second generation. We demonstrate how the measurement of the first or second generation sfermion spectrum may be used to constrain the underlying grand unification structure. The smallness of first and second generation Yukawa interactions allows us to perform an analytic analysis, deriving expressions for the high scale parameters in terms of the low scale sfermion masses. We also describe a sum rule that provides an $SO(10)$ mass prediction, distinct from $SU(5)$, and discuss $E_6$ models, both with and without extra exotic matter at low energies. The derived relations are compared with numerical results including two-loop running and the full Yukawa dependence.

We consider charged Higgs and $W^{\prime }$ gauge boson contributions to the quasielastic scattering ${\nu }_{\tau }+n\to {\tau }^{-}+p$ and ${\overline{\nu }}_{\tau }+p\to {\tau }^{+}+n$. These effects modify the standard model cross section for these processes and thus impact the extraction of the neutrino mixing angles ${\theta }_{23}$ and ${\theta }_{13}$. We include form factor effects in our calculations and find the deviation of the actual mixing angle from the measured one, assuming the standard model cross section, can be significant and can depend on the energy of the neutrino.

We search for possible symmetries present in the leptonic mixing data from $SU(3)$ subgroups of order up to 511. Theoretical results based on symmetry are compared with global fits of experimental data in a chi-squared analysis, yielding the following results. There is no longer a group that can produce all the mixing data without a free parameter, but a number of them can accommodate the first or the second column of the mixing matrix. The only group that fits the third column is $\Delta (150)$. It predicts ${sin}^{2}2{\theta }_{13}=0.11$ and ${sin}^{2}2{\theta }_{23}=0.94$, in good agreement with experimental results.

We present a measurement of $D^0\mathrm{\text{−}}{\overline{D}}^0$ mixing and $CP$ violation using the ratio of lifetimes simultaneously extracted from a sample of $D^0$ mesons produced through the flavor-tagged process $D^{*+}\to D^0{\pi }^{+}$, where $D^0$ decays to $K^{\mp }{\pi }^{\pm }$, $K^{-}{K}^{+}$, or ${\pi }^{-}{\pi }^{+}$, along with the untagged decays $D^0\to K^{\mp }{\pi }^{\pm }$ and $D^0\to K^{-}{K}^{+}$. The lifetimes of the $CP$-even, Cabibbo-suppressed modes $K^{-}{K}^{+}$ and ${\pi }^{-}{\pi }^{+}$ are compared to that of the $CP$-mixed mode $K^{\mp }{\pi }^{\pm }$ in order to measure $y_{CP}$ and $\Delta Y$. We obtain $y_{CP}=[0.72\pm 0.18(\mathrm{stat})\pm 0.12(\mathrm{syst})]\%$ and $\Delta Y=[0.09\pm 0.26(\mathrm{stat})\pm 0.06(\mathrm{syst})]\%$, where $\Delta Y$ constrains possible $CP$ violation. The $y_{CP}$ result excludes the null mixing hypothesis at $3.3\sigma$ significance. This analysis is based on an integrated luminosity of $468{\mathrm{fb}}^{-1}$ collected with the BABAR detector at the PEP-II asymmetric-energy $e^{+}{e}^{-}$ collider.

Using a data sample of $2.25\times {10}^8$ $J/\psi$ events collected with the BESIII detector, we present the first observation of the decays of ${\eta }_c$ mesons to ${\Sigma }^{+}{\overline{\Sigma }}^{-}$ and ${\Xi }^{-}{\overline{\Xi }}^{+}$. The branching fractions are measured to be $(2.11\pm {0.28}_{\mathrm{stat}}\pm {0.18}_{\mathrm{syst}}\pm {0.50}_{\mathrm{PDG}})\times {10}^{-3}$ and $(0.89\pm {0.16}_{\mathrm{stat}}\pm {0.08}_{\mathrm{syst}}\pm {0.21}_{\mathrm{PDG}})\times {10}^{-3}$ for ${\eta }_c\to {\Sigma }^{+}{\overline{\Sigma }}^{-}$ and ${\Xi }^{-}{\overline{\Xi }}^{+}$, respectively. These branching fractions provide important information on the helicity selection rule in charmonium-decay processes.

We develop a superfield approach to the effective potential in the supersymmetric Chern-Simons theory coupled to matter and, in the Landau gauge, calculate the one-loop Kählerian effective potential and give some qualitative prescriptions for the two-loop one.

We study the cosmological effect of the simple scalar-torsion ($0^{+}$) mode in the Poincaré gauge theory of gravity. We find that for the nonconstant (affine) curvature case the early evolution of the torsion density ${\rho }_T$ has a radiation-like asymptotic behavior of $a^{-4}$ with $a$ representing the scale factor, along with the stable point of the torsion pressure ($P_T$) and density ratio $P_T/{\rho }_T\to 1/3$ in the high redshift regime ($z\gg 0$), which is different from the previous result in the literature. We use the Laurent expansion to resolve the solution. We also illustrate our result by the execution of numerical computations.

Two-step dissipation is studied in supersymmetric models in which the field in motion couples to bulk fields in the higher-dimensional space. Since the Kaluza-Klein tower of the intermediate field changes its mass spectrum during the evolution, there could be back reaction from the tower. Then the system may eventually cause significant dissipation of the kinetic energy if the tower is coupled to light fields in the thermal bath. To see what happens in the higher-dimensional theory, we consider three models for the scenario, which are carefully prepared. In these models the extension is obvious but it does not disturb the original setups. The third model suggests that the evolution of the volume moduli may feel significant friction from the Kaluza-Klein tower.

We argue that the observed UV finiteness of the 3-loop extended supergravities may be a manifestation of a hidden local superconformal symmetry of supergravity. We focus on the $SU(2,2|4)$ dimensionless superconformal model. In the Poincaré gauge where the compensators are fixed to ${\varphi }^2=6M_P^2$ this model becomes a pure classical $N=4$ Einstein supergravity. We argue that in $N=4$ the higher-derivative superconformal invariants like ${\varphi }^{-4}{W}^2{\overline{W}}^2$ and the consistent local anomaly $\delta (\ln \varphi W^2)$ are not available. This conjecture on hidden local $N=4$ superconformal symmetry of Poincaré supergravity may be supported by subsequent loop computations.

We discuss the event rate in the DeepCore array due to neutrino flux produced by annihilations and decays of Galactic dark matter. This event rate is calculated with a 10 GeV threshold energy, which is smaller than the threshold energy taken in previous works. Taking into account the background event rate due to the atmospheric neutrino flux, we evaluate the sensitivity of the DeepCore array for probing the dark matter annihilation cross section and decay time. The sensitivity studies include the annihilation modes $\chi \chi \to b\overline{b}$, ${\tau }^{+}{\tau }^{-}$, ${\mu }^{+}{\mu }^{-}$, and $\nu \overline{\nu }$, and decay modes $\chi \to b\overline{b}$, ${\tau }^{+}{\tau }^{-}$, ${\mu }^{+}{\mu }^{-}$, and $\nu \overline{\nu }$. We compare our results with corresponding constraints derived from observations of WMAP, ACT, and Fermi-LAT.

Since future, precise theory of neutrino oscillations should include the understanding of the neutrino mass generation and a precise, relativistic description of hadrons, and observing that such a future theory may require Dirac’s front form of Hamiltonian dynamics, we provide a preliminary front form description of neutrino oscillations using the Feynman–Gell-Mann–Levy version of an effective theory in which leptons interact directly with whole nucleons and pions, instead of with quarks via intermediate bosons. The interactions are treated in the lowest-order perturbative expansion in the coupling constants $G_F$ and $F_{\pi }$ in the effective theory, including a perturbative solution of the coupled constraint equations. Despite missing quarks and their binding mechanism, the effective Hamiltonian description is sufficiently precise for showing that the standard oscillation formula results from the interference of amplitudes with different neutrinos in virtual intermediate states. This holds provided that the inherent experimental uncertainties of preparing beams of incoming and measuring rates of production of outgoing particles are large enough for all of the different neutrino intermediate states to contribute as alternative virtual paths through which the long-baseline scattering process can manifest itself. The result that an approximate, effective front form theory reproduces the standard oscillation formula at the level of transition rates for currently considered long-baseline experiments—even though the space-time development of scattering is traced differently and the relevant interaction Hamiltonians are constructed differently than in the commonly used instant form of dynamics—has two implications. It shows that the common interpretation of experimental results is not the only one, and it opens the possibility of considering more precise theories taking advantage of the features of the front form that are not available in the instant form.

The breather is a vibrating multifermion bound state of the massless Gross-Neveu model, originally found by Dashen, Hasslacher, and Neveu in the large $N$ limit. We exhibit the salient features of this state and confirm that it solves the relativistic time-dependent Hartree-Fock equations. We then solve the scattering problem of two breathers with arbitrary internal parameters and velocities, generalizing an ansatz recently developed for the baryon-baryon scattering problem in the same model. The exact analytical solution is given and illustrated with a few examples.

We analyze the late-time evolution of the Universe in the framework of the self-consistent model, in which dark matter is influenced by the Archimedean-type force proportional to the four-gradient of the dark energy pressure. Dark energy is considered as a fluid with the equation of state of the relaxation type, which takes into account a retardation of the dark energy response to the Universe’s accelerated expansion. Dark matter is guided by the Archimedean-type force, which redistributes the total energy of the dark fluid between its two constituents, dark energy and dark matter, in the course of the Universe’s accelerated expansion. We focus on the constraints for the dark energy relaxation time parameter, for the dark energy equation of state parameter, and for the Archimedean-type coupling constants, which guarantee big rip avoidance. In particular, we show that the Archimedean-type coupling protects the Universe from the big rip scenario with asymptotically infinite negative dark energy pressure, and that the little rip is the fate of the Universe with the Archimedean-type interaction inside the dark fluid.

The gauge-gravity duality can be used to relate connected multipoint graviton functions to connected multipoint correlation functions of the stress tensor of a strongly coupled fluid. Here, we show how to construct the connected graviton functions for a particular kinematic regime that is ideal for discriminating between different gravitational theories, in particular between Einstein theory and its leading-order string theory correction. Our analysis begins with the one-particle irreducible graviton amplitudes in an anti-de Sitter black brane background. We show how these can be used to calculate the connected graviton functions and demonstrate that the two types of amplitudes agree in some cases. It is then asserted on physical grounds that this agreement persists in all cases for both Einstein gravity and its leading-order correction. This outcome implies that the corresponding field-theory correlation functions can be read off directly from the bulk Lagrangian, just as can be done for the ratio of the shear viscosity to the entropy density.

Inspiralling black hole-neutron star binaries emit a complicated gravitational wave signature, produced by multiple harmonics sourced by their strong local gravitational field and further modulated by the orbital plane’s precession. Some features of this complex signal are easily accessible to ground-based interferometers (e.g., the rate of change of frequency), others less so (e.g., the polarization content), and others still are unavailable (e.g., features of the signal out of band). For this reason, an ambiguity function (a diagnostic of dissimilarity) between two such signals varies on many parameter scales and ranges. In this paper, we present a method for computing an approximate, effective Fisher matrix from variations in the ambiguity function on physically pertinent scales which depend on the relevant signal-to-noise ratio. As a concrete example, we explore how higher harmonics improve parameter measurement accuracy. As previous studies suggest, for our fiducial black hole-neutron star binaries and for plausible signal amplitudes, we see that higher harmonics at best marginally improve our ability to measure parameters. For nonprecessing binaries, these Fisher matrices separate into intrinsic (mass, spin) and extrinsic (geometrical) parameters; higher harmonics principally improve our knowledge about the line of sight. For the precessing binaries, the extra information provided by higher harmonics is distributed across several parameters. We provide concrete estimates for measurement accuracy, using coordinates adapted to the precession cone in the detector’s sensitive band.

We study a nonlocally modified gravity model proposed by Deser and Woodard [Phys. Rev. Lett. 99, 111301 (2007)] which gives an explanation for current cosmic acceleration. By deriving and solving the equations governing the evolution of the structure in the Universe, we show that this model predicts a pattern of growth that differs from standard general relativity ($+\mathrm{\text{dark energy}}$) at the 10%–30% level. These differences will be easily probed by the next generation of galaxy surveys, so the model should be tested shortly.