Using data from the Sydney University Giant Air-Shower Recorder and the Akeno Giant Air-Shower Array experiments taken during a 10 yr period with nearly uniform exposure to the entire sky, we search for large-scale anisotropy patterns in the arrival directions of cosmic rays with energies $>{10}^{19.6}\mathrm{eV}.$ We determine the angular power spectrum from an expansion in spherical harmonics for modes out to $\mathcal{l}=5.\mathrm{}$ Based on available statistics, we find no significant deviation from isotropy. We compare the rather modest results which can be extracted from existing data samples with the results that should be forthcoming as new full-sky observatories begin operation.

Using improved Ge and Si detectors, better neutron shielding, and increased counting time, the Cryogenic Dark Matter Search (CDMS) experiment has obtained stricter limits on the cross section of weakly interacting massive particles (WIMPs) elastically scattering from nuclei. Increased discrimination against electromagnetic backgrounds and reduction of the neutron flux confirm WIMP-candidate events previously detected by CDMS were consistent with neutrons and give limits on spin-independent WIMP interactions which are $>2\mathrm{}\times$ lower than previous CDMS results for high WIMP mass, and which exclude new parameter space for WIMPs with mass between 8 and $20\mathrm{GeV}{/c}^2.$

We study the breakdown of CPT symmetry which can occur in the decay process $B\overline{B}\to l^{\pm }{X}^{\mp }f$ with f being a CP eigenstate. In this process, the standard model expectations for time-ordered semileptonic and hadronic events, i.e., which of the two decays takes place first, can be altered in the case that there is a violation of CPT symmetry. To illustrate this possibility, we identify and study several time-integrated observables. We find that an experiment with ${10}^{9}B\overline{B}$ pairs has the capability of improving the bound on the CPT violating parameter or perhaps observe CPT violation.

The Higgs boson production $pp\left(p\overline{p}\right)\to bh+X$ via $b\overrightarrow{g}\mathrm{bh}$ at hadron colliders, which may be an important channel for testing the bottom quark Yukawa coupling, is subject to large supersymmetric quantum corrections. In this work the one-loop supersymmetric (SUSY) QCD corrections to this process are evaluated and are found to be quite sizable in some parameter space. We also study the behavior of the corrections in the limit of heavy SUSY masses and find the remnant effects of SUSY QCD. These remnant effects, which are left over in the Higgs sector by the heavy sparticles, are found to be so sizable (for a light CP-odd Higgs boson and large $\tan \beta )$ that they might be observable in future experiments. The exploration of such remnant effects is important for probing SUSY, especially in the case that the sparticles are too heavy (above TeV) to be directly discovered in future experiments.

Lead perchlorate, part of the OMNIS supernova neutrino detector, contains two nuclei ${}^{208}\mathrm{Pb}$ and ${}^{35}\mathrm{Cl}$ that might be used to study nucleon decay. Both would produce signatures that will make them especially useful for studying less-well-studied neutron decay modes, e.g., those in which only neutrinos are emitted.

Two natural patterns of quark mass matrices are constructed at the electroweak scale, and their corresponding Yukawa coupling matrices are obtained at very high energy scales by use of the renormalization-group equations in the minimal supersymmetric standard model. It is found that the structural features of both patterns are essentially stable against renormalization effects. Some comments are also given on other possible ways to construct the stable textures of quark mass matrices.

In this Reply I present some arguments in favor of the stability of the topological defect composed by global and magnetic monopoles.

We point out a problem with the stability of composite (global-magnetic) monopoles recently proposed by J. Spinelly, U. de Freitas, and E.R. Bezerra de Mello [Phys. Rev. D 66, 024018 (2002)].

We show that the families of effective actions considered by Jacobson et al. to study Lorentz invariance violations contain a class of models that represent pure general relativity with a Euclidean signature. We also point out that some members of this family of actions preserve Lorentz invariance in a generalized sense.

We argue that the quartic fermionic potential of five-dimensional Chern-Simons supergravity induces spontaneous symmetry breaking, in a phenomenon bearing a close connection with the Nambu–Jona-Lasinio model.

The quark number susceptibility, associated with the conserved quark number density, is closely related to the baryon and charge fluctuations in the quark-gluon plasma, which might serve as signature for the quark-gluon plasma formation in ultrarelativistic heavy-ion collisions. In addition to QCD lattice simulations, the quark number susceptibility has been calculated recently using a resummed perturbation theory (hard thermal loop resummation). In the present work we show, based on general arguments, that the computation of this quantity neglecting hard thermal loop vertices contradicts the Ward identity and violates the thermodynamic sum rule following from quark number conservation. We further show that the hard thermal loop perturbation theory is consistent with the thermodynamic sum rule.

Topological charged black holes coupled with a cosmological constant in $R^2\times X^{D-2}$ spacetimes are studied, where $X^{D-2}$ is an Einstein space of the form ${}^{\left(D-2\right)}{R}_{\mathrm{AB}}=k(D-{3)h}_{\mathrm{AB}}.$ The global structure for the four-dimensional spacetimes with $k=0\mathrm{}$ is investigated systematically. The most general solutions that represent a type II fluid in such a high dimensional spacetime are found and show that topological charged black holes can be formed from the gravitational collapse of such a fluid. When the spacetime is (asymptotically) self-similar, the collapse always forms black holes for $k=0,$ $-1,$ in contrast with the case $k=1,$ where it can form either black holes or naked singularities.

There are indications from the study of quasar absorption spectra that the fine structure constant $\alpha$ may have been measurably smaller for redshifts $z>\mathrm{}2.\mathrm{}$ Analyses of other data ${(}^{149}\mathrm{Sm}$ fission rate for the Oklo natural reactor, variation of ${}^{187}\mathrm{Re}\beta$-decay rate in meteorite studies, atomic clock measurements) which probe variations of $\alpha$ in the more recent past imply much smaller deviations from its present value. In this work we tie the variation of $\alpha$ to the evolution of the quintessence field proposed by Albrecht and Skordis, and show that agreement with all these data, as well as consistency with Wilkinson Microwave Anisotropy Probe observations, can be achieved for a range of parameters. Some definite predictions follow for upcoming space missions searching for violations of the equivalence principle.

In this paper, by analyzing the instability against spatially homogeneous and anisotropic perturbations of the Kantowski-Sachs type during different cosmological epochs, we show that it is a theoretical consequence of general relativity that the KS universe must be open or flat if it underwent a matter-dominated and/or radiation-dominated era in its past evolution, which theoretically confirms the flatness of our observable Universe.

We describe an optical simulation program that models a complete, coupled-cavity interferometer such as those used by the Laser Interferometer Gravitational-Wave Observatory (LIGO) Project. A wide variety of interferometer deformations can be modeled, including general surface roughness and substrate inhomogeneities, with no a priori symmetry assumptions about the nature of interferometer imperfections. Several important interferometer parameters are optimized automatically to achieve the best possible sensitivity for each new set of perturbed mirrors. The simulation output dataset includes the circulating powers and electric fields at various points in the interferometer, both for the main carrier beam and for its signal-sideband auxiliary beams, allowing an explicit calculation of the shot-noise-limited gravitational-wave sensitivity of the interferometric detector to be performed. Here we present an overview of the physics simulated by the program, and demonstrate its use with a series of runs showing the degradation of LIGO performance caused by realistically deformed mirror profiles. We then estimate the effect of this performance degradation upon the detectability of astrophysical sources of gravitational waves. We conclude by describing applications of the simulation program to LIGO research and development efforts.

Recently it has been pointed out that no limits can be put on the scale of fermion mass generation (M) in technicolor models, because the relation between the fermion masses ${(m}_f)$ and M depends on the dimensionality of the interaction responsible for generating the fermion mass. Depending on this dimensionality it may happen that $m_f$ does not depend on M at all. We show that exactly in this case $m_f$ may reach its largest value, which is almost saturated by the top quark mass. We make a few comments on the question of how large a dynamically generated fermion mass can be.

We compute the low-energy mass spectrum of lattice QCD in the large $N_C$ limit. Expanding around a gauge-invariant ground state, which spontaneously breaks the discrete chiral symmetry, we derive an improved strong-coupling expansion and evaluate, for any value of $N_C,$ the masses of the low-lying states in the unflavored meson spectrum. We then take the ’t Hooft limit by rescaling $g^2{N}_C\to g^2;$ the ’t Hooft limit is smooth and no arbitrary parameters are needed. We find, already at the fourth order of the strong-coupling perturbation theory, a very good agreement between the results of our lattice computation and the known continuum values.

Various authors have noted that, in particular models, the upper bound on the axion decay constant may not hold. We point out that within supersymmetry this is a generic issue. For large decay constants, the cosmological problems associated with the axion’s scalar partner are far more severe than those of the axion. We survey a variety of models, both for the axion multiplet and for cosmology, and find that in many cases where the cosmological problems of the saxion are solved, the usual upper bound on the axion is significantly relaxed. We discuss, more generally, the cosmological issues raised by the pseudoscalar members of moduli multiplets, and find that they are potentially quite severe.

We study single charged Higgs boson production in photon-photon collisions as a probe of the new dynamics of Higgs interactions. This is particularly important when the mass ${(M}_{H^{\pm }})$ of charged Higgs bosons ${(H}^{\pm })$ is relatively heavy and above the kinematic limit of the pair production ${(M}_{H^{\pm }}>\sqrt{s}/2).\mathrm{}$ We analyze the cross sections of single charged Higgs boson production from the photon-photon fusion processes $\gamma \overrightarrow{\gamma }{\tau }^{-}\overline{\nu }{H}^{+}$ and $\gamma \overrightarrow{\gamma }b\overline{c}{H}^{+},$ as motivated by the minimal supersymmetric standard model and the dynamical top-color model. We find that the cross sections at such a $\gamma \gamma$ collider can be sufficiently large even for $M_{H^{\pm }}>\sqrt{s}/2,$ and is typically one to two orders of magnitude higher than that at its parent $e^{-}{e}^{+}$ collider. We further demonstrate that the polarized photon beams can provide an important means to determine the chirality structure of Higgs Yukawa interactions with the fermions.

We investigate higher twist contributions to the transverse momentum broadening of Drell-Yan pairs in proton nucleus collisions. We reexamine the contribution of matrix elements of twist 4 and generalize this to matrix elements of arbitrary twist. An estimate of the maximal nuclear broadening effect is derived. A model for nuclear enhanced matrix elements of arbitrary twist allows us to give the result of a resummation of all twists in closed form. Subleading corrections to the maximal broadening are discussed qualitatively.