An eikonalized elastic proton-proton and proton-antiproton scattering amplitude $F(s,t)$, calculated from QCD as a finite sum of gluon ladders, is compared with the existing experimental data on the total cross section and the ratio $\rho (s,0)=\mathrm{Re}F(s,0)/\mathrm{Im}F(s,0)$ of the real part to the imaginary part of the forward amplitude. Predictions for the expected LHC energies are given.

We study the finite temperature behavior of light scalar and pseudoscalar meson properties in the context of a three-flavor nonlocal chiral quark model. The model includes mixing with active strangeness degrees of freedom, and takes care of the effect of gauge interactions by coupling the quarks with the Polyakov loop. We analyze the chiral restoration and deconfinement transitions, as well as the temperature dependence of meson masses, mixing angles and decay constants. The critical temperature is found to be $T_c\simeq 202\mathrm{MeV}$, in better agreement with lattice results than the value recently obtained in the local SU(3) PNJL model. It is seen that above $T_c$ pseudoscalar meson masses get increased, becoming degenerate with the masses of their chiral partners. The temperatures at which this matching occurs depend on the strange quark composition of the corresponding mesons. The topological susceptibility shows a sharp decrease after the chiral transition, signalling the vanishing of the $U(1{)}_A$ anomaly for large temperatures.

If the Higgs boson were the only particle within the LHC accessible range, precision measurement of the Higgs’s properties would play a unique role in studying electroweak symmetry breaking as well as possible new physics. We try to use low energy experiments such as rare $B$ decay to constrain a challenging decay mode of Higgs, in which a Higgs decays to a pair of light ($\approx 1\sim 2\mathrm{GeV}$) SM singlet $S$ and becomes invisible. By using the current experimental bound of rare decay $B\to K\nu \overline{\nu }$ and computing the contribution of $B\to KSS$ to (the) $B\to K+\mathrm{E̸}$, we obtain an upper bound on the Higgs coupling to such light singlet. It is interesting that the partial width of the invisible decay mode $h\to SS$ by taking the upper bound value of coupling is at a comparable level with $h\to WW/ZZ$ or $W{W}^{(*)}$ decay modes, making the Higgs identifiable but with a different predicted decay branching ratio from [the] standard model Higgs decay. It will then have an impact on precision measurement of the Higgs’s properties. We also study the implication for cosmology from such a light singlet and propose a solution to the potential problem.

We consider the vacuum energy for a configuration of a sphere in front of a plane, both obeying the conductor boundary condition, at small separation. For the separation becoming small we derive the first next-to-leading order of the asymptotic expansion in the separation-to-radius ratio $\epsilon$. This correction is of order $\epsilon$. Opposite to the scalar cases it contains also contributions proportional to logarithms in first and second order, $\epsilon \ln \epsilon$ and $\epsilon (\ln \epsilon {)}^2$. We compare this result with the available findings of numerical and experimental approaches.

The breaking of Lorentz symmetry via a dynamical mechanism, with a tensor field which takes on a nonzero expectation value in vacuum, has been a subject of significant research activity in recent years. In certain models of this type, the perturbations of the “Lorentz-violating field” about this background may be identified with known forces. I present the results of applying this interpretation to the “generalized bumblebee models” found in a prior work. In this model, the perturbations of a Lorentz-violating vector field can be interpreted as a photon field. However, the speed of propagation of this “bumblebee photon” is direction-dependent and differs from the limiting speed of conventional matter, leading to measurable physical effects. Bounds on the parameters of this theory can then be derived from resonator experiments, accelerator physics, and cosmic-ray observations.

We study how gravitational duality acts on rotating solutions, using the Kerr-NUT black hole as an example. After properly reconsidering how to take into account both electric (i.e. masslike) and magnetic (i.e. NUT-like) sources in the equations of general relativity, we propose a set of definitions for the dual Lorentz charges. We then show that the Kerr-NUT solution has nontrivial such charges. Further, we clarify in which respect Kerr’s source can be seen as a mass $M$ with a dipole of NUT charges.

We use the recent results on dark matter searches of the 22-string IceCube detector to probe the remaining allowed window for strongly interacting dark matter in the mass range ${10}^4<m_X<{10}^{15}\mathrm{GeV}$. We calculate the expected signal in the 22-string IceCube detector from the annihilation of such particles captured in the Sun and compare it to the detected background. As a result, the remaining allowed region in the mass versus cross section parameter space is ruled out. We also show the expected sensitivity of the complete IceCube detector with 86 strings.

On the basis of the Gerlach-Sengupta theory of gauge-invariant perturbations, a formula of the integrated Sachs-Wolfe effect for a central observer is derived on general spherically symmetric spacetimes. It will be useful for comparative studies of theoretical and observational aspects of the integrated Sachs-Wolfe effect in the Lemaitre-Tolman-Bondi cosmological models which have been noticed by explaining the apparent acceleration without cosmological constant.

We study the parameter space of cold dark matter axions in two cosmological scenarios with nonstandard thermal histories before big bang nucleosynthesis: the low-temperature reheating (LTR) cosmology and the kination cosmology. If the Peccei-Quinn symmetry breaks during inflation, we find more allowed parameter space in the LTR cosmology than in the standard cosmology and less in the kination cosmology. On the contrary, if the Peccei-Quinn symmetry breaks after inflation, the Peccei-Quinn scale is orders of magnitude higher than standard in the LTR cosmology and lower in the kination cosmology. We show that the axion velocity dispersion may be used to distinguish some of these nonstandard cosmologies. Thus, axion cold dark matter may be a good probe of the history of the Universe before big bang nucleosynthesis.

In this paper, by use of the holographic principle together with the equipartition law of energy and the Unruh temperature, we derive the Friedmann equations of a Friedmann-Robertson-Walker universe.

We consider the possibility that the recently reported events at the CDMS-II direct dark matter detection experiment are the result of a coherent scattering of supersymmetric neutralinos. In such a scenario we argue that nonuniversal soft supersymmetry breaking gaugino masses are favored with a resulting lightest neutralino with significant Higgsino and wino components. We discuss the accompanying signals which must be seen at liquid-xenon direct detection experiments and indirect detection experiments if such a supersymmetric interpretation is to be maintained. We illustrate the possible consequences for early discovery channels at the LHC via a set of benchmark points designed to give rise to an observed event rate comparable to the reported CDMS-II data.

Nucleon properties are investigated in background electric fields. As the magnetic moments of baryons affect their relativistic propagation in constant electric fields, electric polarizabilities cannot be determined without knowledge of magnetic moments. This is analogous to the experimental situation, for which determination of polarizabilities from the Compton amplitude requires subtraction of Born terms. With the background field method, we devise combinations of nucleon correlation functions in constant electric fields that isolate magnetic moments and electric polarizabilities. Using an ensemble of anisotropic gauge configurations with dynamical clover fermions, we demonstrate how both observables can be determined from lattice QCD simulations in background electric fields. We obtain results for the neutron and proton, however, our study is currently limited to electrically neutral sea quarks. The value we extract for the nucleon isovector magnetic moment is comparable to those obtained from measuring lattice three-point functions at similar pion masses.

We investigate the exclusive rare $B_c\to D_{(s)}{\nu }_{\ell }{\overline{\nu }}_{\ell }$ and $B\to D_{(s)}{\ell }^{+}{\ell }^{-}$ ($\ell =e$, $\mu$, $\tau$) decays within the standard model and the light-front quark model constrained by the variational principle for the QCD-motivated effective Hamiltonian. The form factors $f_{\pm }(q^2)$ and $f_T(q^2)$ are obtained from the analytic continuation method in the $q^{+}=0$ frame. While the form factors $f_{+}(q^2)$ and $f_T(q^2)$ are free from the zero mode, the form factor $f_{-}(q^2)$ is not free from the zero mode in the $q^{+}=0$ frame. We discuss the covariance (i.e. frame independence) of our model calculation and quantify the zero-mode contributions to $f_{-}(q^2)$ for $B_c\to D_{(s)}$ decays. The branching ratios and the longitudinal lepton polarization asymmetries are calculated with and without the long-distance contributions. Our numerical results for the nonresonant branching ratios for $B_c\to D(D_s)\sum _{}^{}{\nu }_{\ell }{\overline{\nu }}_{\ell }$ and $B_c\to D(D_s){\ell }^{+}{\ell }^{-}$ are in the order of ${10}^{-8}$ (${10}^{-7}$) and ${10}^{-9}$ (${10}^{-8}$), respectively. The averaged values of the lepton polarization asymmetries obtained from the linear (harmonic oscillator) potential parameters are found to be $-0.99$ ($-0.99$) for $B_c\to D{\mu }^{+}{\mu }^{-}$ and $-0.16$ ($-0.15$) for $B_c\to D{\tau }^{+}{\tau }^{-}$, and $-0.98$ ($-0.98$) for $B_c\to D_s{\mu }^{+}{\mu }^{-}$ and $-0.14$ ($-0.12$) for $B_c\to D_s{\tau }^{+}{\tau }^{-}$, respectively.

We use the conventional $F$ and $D$ octet and decimet generator matrices to reformulate chiral properties of local (nonderivative) and one-derivative nonlocal fields of baryons consisting of three quarks with flavor $SU(3)$ symmetry that were expressed in $SU(3)$ tensor form by Chen et al. [Phys. Rev. D 78, 054021 (2008)]. We show explicitly the chiral transformations of the $[(6,3)\oplus (3,6)]$ chiral multiplet in the “$SU(3)$ particle basis,” for the first time to our knowledge, as well as those of the $(3,\overline{3})\oplus (\overline{3},3)$, $(8,1)\oplus (1,8)$ multiplets, which have been recorded before by Bardeen and Lee [Phys. Rev. 177, 2389 (1969)] and Lee [Phys. Rev. 170, 1359 (1968)]. We derive the vector and axial-vector Noether currents, and show explicitly that their zeroth (chargelike) components close the $S{U}_L(3)\times S{U}_R(3)$ chiral algebra. We use these results to study the effects of mixing of (three-quark) chiral multiplets on the axial current matrix elements of hyperons and nucleons. We show, in particular, that there is a strong correlation, indeed a definite relation between the flavor-singlet (i.e. the zeroth), the isovector (the third), and the eighth flavor component of the axial current, which is in decent agreement with the measured ones.

We argue that the $A_4$ symmetry as required by three flavors of fermions may well-embed in the $\mathrm{SU}(3{)}_C\otimes \mathrm{SU}(3{)}_L\otimes \mathrm{U}(1{)}_X$ gauge model. The new neutral fermion singlets as introduced in a canonical seesaw mechanism can be combined with the standard model lepton doublets to perform $\mathrm{SU}(3{)}_L$ triplets. Various leptoscalar multiplets such as singlets, doublets, and triplets as played in the models of $A_4$ are unified in single $\mathrm{SU}(3{)}_L$ antisextets. As a result, naturally light neutrinos with various kinds of mass hierarchies are obtained as a combination of type I and type II seesaw contributions. The observed neutrino mixing pattern in terms of the Harrison-Perkins-Scott proposal is obtained by enforcing the $A_4$ group. The quark masses and Cabibbo-Kobayashi-Maskawa mixing matrix are also discussed. By virtue of very heavy antisextets, the nature of the vacuum alignments of scalar fields can be given.

By means of solving the Bethe-Salpeter equation with the minimal perturbative kernel (ladder approximation) in the arbitrary covariant gauge, there was found a series of intercepts of meson Regge trajectories associated with colorless singularities of the four-quark Green function in $\mathrm{SU}(N_c)$ quantum chromodynamics with massless quarks. The gauge and renorm-invariance of the result is grounded.

We propose a novel scheme to classify the different options for resolution of the black hole loss of information problem that is independent of the details of the underlying theory of quantum gravity. We distinguish first between radical options, which require a quantum theory of gravity which has large deviations from semiclassical physics on macroscopic scales, such as nonlocality or endowing horizons with special properties not seen in the semiclassical approximation, and conservative options, which do not need such help. Among the conservative options, we conclude that restoring unitary evolution relies on elimination of singularities. We argue that this should hold also in the anti-de Sitter/conformal field theories correspondence.

We calculate how strongly one can put constraints on alternative theories of gravity such as Brans-Dicke and massive graviton theories with LISA. We consider inspiral gravitational waves from a compact binary composed of a neutron star and an intermediate mass black hole in Brans-Dicke (BD) theory and that composed of a super massive black hole in massive graviton theories. We use the restricted second post-Newtonian waveforms including the effects of spins. We also take both precession and eccentricity of the orbit into account. For simplicity, we set the fiducial value for the spin of one of the binary constituents to zero so that we can apply the approximation called simple precession. We perform the Monte Carlo simulations of ${10}^4$ binaries, estimating the determination accuracy of binary parameters including the BD parameter ${\omega }_{\mathrm{BD}}$ and the Compton wavelength of graviton ${\lambda }_g$ for each binary using the Fisher matrix method. We find that including both the spin-spin coupling $\sigma$ and the eccentricity $e$ into the binary parameters reduces the determination accuracy by an order of magnitude for the Brans-Dicke case, while it has less influence on massive graviton theories. On the other hand, including precession enhances the constraint on ${\omega }_{\mathrm{BD}}$ only 20% but it increases the constraint on ${\lambda }_g$ by several factors. Using a $(1.4+1000)M_{\odot }$ neutron star/black hole binary of $\mathrm{SNR}=\sqrt{200}$, one can put a constraint ${\omega }_{\mathrm{BD}}>6944$, while using a $({10}^7+{10}^6)M_{\odot }$ black hole/black hole binary at 3 Gpc, one can put ${\lambda }_g>3.10\times {10}^{21}\mathrm{cm}$, on average. The latter is 4 orders of magnitude stronger than the one obtained from the solar system experiment. These results are consistent with previous results within uncontrolled errors and indicate that the effects of precession and eccentricity must be taken carefully in the parameter estimation analysis.

We show that the linearization of all exact solutions of classical chiral gravity around the ${\mathrm{AdS}}_3$ vacuum have positive energy. Nonchiral and negative-energy solutions of the linearized equations are infrared divergent at second order, and so are removed from the spectrum. In other words, chirality is confined and the equations of motion have linearization instabilities. We prove that the only stationary, axially symmetric solutions of chiral gravity are BTZ black holes, which have positive energy. It is further shown that classical log gravity—the theory with logarithmically relaxed boundary conditions—has finite asymptotic symmetry generators but is not chiral and hence may be dual at the quantum level to a logarithmic conformal field theories (CFT). Moreover we show that log gravity contains chiral gravity within it as a decoupled charge superselection sector. We formally evaluate the Euclidean sum over geometries of chiral gravity and show that it gives precisely the holomorphic extremal CFT partition function. The modular invariance and integrality of the expansion coefficients of this partition function are consistent with the existence of an exact quantum theory of chiral gravity. We argue that the problem of quantizing chiral gravity is the holographic dual of the problem of constructing an extremal CFT, while quantizing log gravity is dual to the problem of constructing a logarithmic extremal CFT.

We study massive graviton propagations of scalar, vector, and tensor modes in the deformed Hořava-Lifshitz gravity by introducing the Lorentz-violating mass term. It turns out that vector and tensor modes are massively propagating on the Minkowski spacetime background. However, adding the mass term does not cure a ghost instability in the Hořava scalar.