We show that in any invisible axion model due to the effects of effective nonrenormalizable interactions related to an energy scale near the Peccei-Quinn, grand unification or even the Planck scale, active neutrinos necessarily acquire masses in the sub-eV range. Moreover, if sterile neutrinos are also included and if appropriate cyclic $Z_N$ symmetries are imposed, it is possible that some of these neutrinos are heavy while others are light.

Recently we reported on the infrared behavior of the Landau gauge gluon and ghost dressing functions in $SU(3)$ Wilson lattice gluodynamics with special emphasis on the Gribov problem. Here we add an investigation of the spectral properties of the Faddeev-Popov operator at $\beta =5.8$ and $6.2$ for lattice sizes ${12}^4$, ${16}^4$ and ${24}^4$. The larger the volume the more of its eigenvalues are found accumulated close to zero. Using the eigenmodes for the spectral representation it turns out that for our smallest lattice $\mathcal{O}(200)$ eigenmodes are sufficient to saturate the ghost propagator at lowest momentum. We associate exceptionally large values of the ghost propagator to extraordinary contributions of low-lying eigenmodes.

The photoproduction rate of pentaquark ${\Theta }^{+}$ is calculated in a hot and dense medium. At high temperature and density, photoproduction energy threshold is increased, due to the restoration of chiral symmetry. Above the threshold, the production cross section is strongly enhanced.

We report measurements of diagonal susceptibilities for the baryon number, ${\chi }_B$, electrical charge, ${\chi }_Q$, third component of isospin, ${\chi }_I$, strangeness, ${\chi }_S$, and hypercharge, ${\chi }_Y$, as well as the off-diagonal ${\chi }_{BQ}$, ${\chi }_{BY}$, ${\chi }_{BS}$, etc. We show that the ratios of susceptibilities in the high-temperature phase are robust variables, independent of lattice spacing, and therefore give predictions for experiments. We also investigate strangeness production and flavor symmetry breaking matrix elements at finite temperature. Finally, we present evidence that in the high-temperature phase of QCD the different flavor quantum numbers are excited in linkages which are exactly the same as one expects from quarks. We present some investigations of these quarklike quasiparticles.

We report a new value of electron $g-2$, or $a_e$, from 891 Feynman diagrams of order ${\alpha }^4$. The FORTRAN codes of 373 diagrams containing closed electron loops have been verified by at least two independent formulations. For the remaining 518 diagrams, which have no closed lepton loop, verification by a second formulation is not yet attempted because of the enormous amount of additional work required. However, these integrals have structures that allow extensive cross-checking as well as detailed comparison with lower-order diagrams through the renormalization procedure. No algebraic error has been uncovered for them. The numerical evaluation of the entire ${\alpha }^4$ term by the integration routine VEGAS gives $-1.7283(35)(\alpha /\pi {)}^4$, where the uncertainty is obtained by careful examination of error estimates by VEGAS. This leads to $a_e=1159652175.86(0.10)(0.26)(8.48)\times {10}^{-12}$, where the uncertainties come from the ${\alpha }^4$ term, the estimated uncertainty of ${\alpha }^5$ term, and the inverse fine structure constant, ${\alpha }^{-1}=137.0360003(10)$, measured by atom interferometry combined with a frequency comb technique, respectively. The inverse fine structure constant ${\alpha }^{-1}(a_e)$ derived from the theory and the Seattle measurement of $a_e$ is $137.03599883(51)$.

We evaluate the impact of heavy-quark masses on transverse momentum ($q_T$) distributions of $W$, $Z$, and supersymmetric neutral Higgs bosons at the Tevatron and LHC. The masses of charm and bottom quarks act as non-negligible momentum scales at small $q_T$ and affect resummation of soft and collinear radiation. We point out inconsistencies in the treatment of heavy-flavor channels at small $q_T$ in massless and fixed-flavor number factorization schemes, and formulate small-$q_T$ resummation in a general-mass variable flavor number factorization scheme. The improved treatment of the quark-mass dependence leads to non-negligible effects in precision measurements of the $W$ boson mass at the LHC and may cause observable modifications in production of Higgs bosons and other particles in heavy-quark scattering.

The Cryogenic Dark Matter Search (CDMS) is an experiment to detect weakly interacting massive particles (WIMPs), which may constitute the universe’s dark matter, based on their interactions with Ge and Si nuclei. We report the results of an analysis of data from the first two runs of CDMS at the Soudan Underground Laboratory in terms of spin-dependent WIMP-nucleon interactions on ${}^{73}\mathrm{Ge}$ and ${}^{29}\mathrm{Si}$. These data exclude new regions of WIMP parameter space, including regions relevant to spin-dependent interpretations of the annual modulation signal reported by the DAMA/NaI experiment.

The Noether charge method for defining the Hamiltonian of a diffeomorphism-invariant field theory is applied to “Einstein-aether” theory, in which gravity couples to a dynamical, timelike, unit-norm vector field. Using the method, expressions are obtained for the total energy, momentum, and angular momentum of an Einstein-aether space-time. The method is also used to discuss the mechanics of Einstein-aether black holes. The derivation of Wald, and Iyer and Wald, of the first law of black hole thermodynamics fails for this theory because the unit-vector is necessarily singular at the bifurcation surface of the Killing horizon. A general identity relating variations of energy and angular momentum to a surface integral at the horizon is obtained, but a thermodynamic interpretation, including a definitive expression for the black hole entropy, is not found.

We provide, in a framework of vectorlike gauge theories, concrete models for conformal sequestering of dynamical supersymmetry (SUSY) breaking in the hidden sector. If the sequestering is sufficiently strong, anomaly mediation of the SUSY breaking may give dominant contributions to the mass spectrum of SUSY standard model particles, leading to negative slepton masses squared. Thus, we also consider a model with gravitational gauge mediation to circumvent the tachyonic slepton problem in pure anomaly-mediation models.

We study cosmology in a five-dimensional brane-world with a stabilizing effective potential for the radion and matter localized on the two branes. We consider the corrections induced by the Gauss-Bonnet contribution to the total action performing an expansion around the two possible static solutions up to second order in the ratio between brane matter energy density and brane tensions. The Friedmann and acceleration equations on the visible brane are obtained and discussed.

In the framework of zeta-function approach the Casimir energy for three simple model system: single delta potential, step function potential and three delta potentials are analyzed. It is shown that the energy contains contributions which are peculiar to the potentials. It is suggested to renormalize the energy using the condition that the energy of infinitely separated potentials is zero which corresponds to subtraction all terms of asymptotic expansion of zeta-function. The energy obtained in this way obeys all physically reasonable conditions. It is finite in the Dirichlet limit, and it may be attractive or repulsive depending on the strength of potential. The effective action is calculated, and it is shown that the surface contribution appears. The renormalization of the effective action is discussed.

In this work two different boundary conditions for first order gravity, corresponding to a null and a negative cosmological constant, respectively, are studied. Both boundary conditions allow one to obtain the standard black hole thermodynamics. Furthermore, both boundary conditions define a canonical ensemble. Additionally the quasilocal energy definition is obtained for the null cosmological constant case.

We identify 31 dimensionless physical constants required by particle physics and cosmology, and emphasize that both microphysical constraints and selection effects might help elucidate their origin. Axion cosmology provides an instructive example, in which these two kinds of arguments must both be taken into account, and work well together. If a Peccei-Quinn phase transition occurred before or during inflation, then the axion dark matter density will vary from place to place with a probability distribution. By calculating the net dark matter halo formation rate as a function of all four relevant cosmological parameters and assessing other constraints, we find that this probability distribution, computed at stable solar systems, is arguably peaked near the observed dark matter density. If cosmologically relevant weakly interacting massive particle (WIMP) dark matter is discovered, then one naturally expects comparable densities of WIMPs and axions, making it important to follow up with precision measurements to determine whether WIMPs account for all of the dark matter or merely part of it.

Inflation generically predicts a stochastic background of gravitational waves over a broad range of frequencies, from those accessible with cosmic microwave background (CMB) measurements, to those accessible directly with gravitational-wave detectors, like NASA’s Big-Bang Observer (BBO) or Japan’s Deci-Hertz Interferometer Gravitational-wave Observer (DECIGO), both currently under study. Here we investigate the detectability of the inflationary gravitational-wave background at BBO/DECIGO frequencies. To do so, we survey a range of slow-roll inflationary models consistent with constraints from the CMB and large-scale structure (LSS). We go beyond the usual assumption of power-law power spectra, which may break down given the 16 orders of magnitude in frequency between the CMB and direct detection, and solve instead the inflationary dynamics for four classes of inflaton potentials. Direct detection is possible in a variety of inflationary models, although probably not in any in which the gravitational-wave signal does not appear in the CMB polarization. However, direct detection by BBO/DECIGO can help discriminate between inflationary models that have the same slow-roll parameters at CMB/LSS scales.

In this work we investigate the effects of primordial magnetic fields on cosmic microwave background anisotropies (CMB). Based on cosmological magneto-hydro dynamic (MHD) simulations [R. Banerjee and K. Jedamzik, Phys. Rev. D 70, 123003 (2004).] we calculate the CMB anisotropy spectra and polarization induced by fluid fluctuations (Alfvén modes) generated by primordial magnetic fields. The strongest effect on the CMB spectra comes from the transition epoch from a turbulent regime to a viscous regime. The balance between magnetic and kinetic energy until the onset of the viscous regime provides a one to one relation between the comoving coherence length $L$ and the comoving magnetic field strength $B$, such as $L\sim 30(B/{10}^{-9}\mathrm{Gauss}{)}^3\mathrm{pc}$. The resulting CMB temperature and polarization anisotropies for the initial power law index of the magnetic fields $n>3/2$ are somewhat different from the ones previously obtained by using linear perturbation theory. In particular, differences can appear on intermediate scales $l<2000$ and small scales $l>20000$. On scales $l<2000$ the CMB anisotropy and polarization spectra are flat in the case of our nonlinear calculations whereas the spectra have a blue index calculated with linear perturbation theory if we assume the velocity fields of baryons induced by the magnetic fields achieved Alfvén velocity due to the turbulent motions on large scales in the early universe. Our calculation gives a constraint on the magnetic field strength in the intermediate scale of CMB observations. Upper limits are set by WMAP and BOOMERANG results for comoving magnetic field strength of $B<28\mathrm{nGauss}$ with a comoving coherence length of $L>0.7\mathrm{Mpc}$ for the most extreme case, or $B<30\mathrm{nGauss}$ and $L>0.8\mathrm{Mpc}$ for the most conservative case. We may also expect higher signals on large scales of the polarization spectra compared to linear calculations. The signal may even exceed the B-mode polarization from gravitational lensing depending on the strength of the primordial magnetic fields. On very small scales, the diffusion damping scale of nonlinear calculations turns out to be much smaller than the one of linear calculations if the comoving magnetic field strength $B>16\mathrm{nGauss}$. If the magnetic field strength is smaller, the diffusion scales become smaller too. Therefore we expect to have both, temperature and polarization anisotropies, even beyond $l>10000$ regardless of the strength of the magnetic fields. The peak values of the temperature anisotropy and the B-mode polarization spectra are approximately $40\mu \mathrm{K}$ and a few $\mu \mathrm{K}$, respectively.

The ’t Hooft and Corrigan-Ramond limits of massless one-flavor QCD consider the two Weyl fermions to be, respectively, in the fundamental representation and the two index antisymmetric representation of the gauge group. We introduce a limit in which one of the two Weyl fermions is in the fundamental representation and the other in the two index antisymmetric representation of a generic $\mathrm{SU}(N)$ gauge group. This theory is chiral and to avoid gauge anomalies a more involved chiral theory is needed. This is the generalized Georgi-Glashow model with one vectorlike fermion. We show that there is an interesting phase in which the considered chiral gauge theory, for any $N$, Higgses via a bilinear condensate: The gauge interactions break spontaneously to ordinary massless one-flavor SU(3) QCD. The additional elementary fermionic matter is uncharged under this SU(3) gauge theory. It is also seen that when the number of colors reduce to three it is exactly this hidden QCD which is revealed.

Reanalyses of LEP data have shown preference to two light $CP$-even Higgs bosons. We discuss implications of such a Higgs boson spectrum for the minimal supersymmetric model extended by a standard model singlet chiral superfield and an additional Abelian gauge invariance [the $\mathrm{U}(1{)}^{\prime }$ model]. We, in particular, determine parameter regions that lead to two light $CP$-even Higgs bosons while satisfying existing bounds on the mass and mixings of the extra vector boson. In these parameter regions, the pseudoscalar Higgs is found to be nearly degenerate in mass with either the lightest or next-to-lightest Higgs boson. Certain parameters of the $\mathrm{U}(1{)}^{\prime }$ model such as the effective $\mu$ parameter are found to be significantly bounded by the LEP two light Higgs signal.

We discuss the determination of deep-inelastic hadron structure in lattice QCD. By using a fictitious heavy-quark, direct calculations of the Compton scattering tensor can be performed in Euclidean space that allow the extraction of the moments of structure functions. This overcomes issues of operator mixing and renormalization that have so far prohibited lattice computations of higher moments. This approach is especially suitable for the study of the twist-two contributions to isovector quark distributions, which is practical with current computing resources. While we focus on the isovector unpolarized distribution, our method is equally applicable to other quark distributions and to generalized parton distributions. By looking at matrix elements such as $⟨{\pi }^{\pm }|T[V^{\mu }(x)A^{\nu }(0)]|0⟩$ (where $V^{\mu }$ and $A^{\nu }$ are vector and axial-vector heavy-light currents) within the same formalism, moments of meson distribution amplitudes can also be extracted.

We calculate the kaon $B$ parameter, $B_K$, to next-to-leading order in staggered chiral perturbation theory. We find expressions for partially quenched QCD with three sea quarks, quenched QCD, and full QCD with $m_u=m_d\ne m_s$. We extend the usual power counting to include the effects of using perturbative (rather than nonperturbative) matching factors. Taste breaking enters through the $O(a^2)$ terms in the effective action, through $\mathcal{O}(a^2)$ terms from the discretization of operators, and through the truncation of matching factors. These effects cause mixing with several additional operators, complicating the chiral and continuum extrapolations. In addition to the staggered expressions, we present $B_K$ at next-to-leading order in continuum $\mathrm{PQ}\chi \mathrm{PT}$ for $N_f=3$ sea quarks with $m_u=m_d\ne m_s$.

Very small mean curvature is a robust prediction of inflation worth rigorous checking. Since current constraints are derived from determinations of the angular-diameter distance to the CMB last-scattering surface, which is also affected by dark energy, they are limited by our understanding of the dark energy. Measurements of luminosity or angular-diameter distances to redshifts in the matter-dominated era can greatly reduce this uncertainty. With a 1% measurement of the distance to $z=3$, combined with the CMB data expected from Planck, one can achieve $\sigma ({\Omega }_k{h}^2)\sim {10}^{-3}$. A nonzero detection at this level would be evidence against inflation or for unusually large curvature fluctuations on super-Hubble scales.