We discuss a model in which the fundamental scale of gravity is restricted to ${10}^{-3}\mathrm{eV}.$ An observable modification of gravity occurs simultaneously at the Hubble distance and at around 0.1 mm. These predictions can be tested both by the table-top experiments and by cosmological measurements. The model is formulated as a brane-world theory embedded in a space with two or more infinite-volume extra dimensions. Gravity on the brane reproduces the four-dimensional laws at observable distances but turns to the high-dimensional behavior at larger scales. To determine the crossover distance we smooth out the singularities in the Green’s functions by taking into account softening of the graviton propagator due to the high-dimensional operators that are suppressed by the fundamental scale. We find that irrespective of the precise nature of microscopic gravity the ultraviolet and infrared scales of gravity modification are rigidly correlated. This fixes the fundamental scale of gravity at ${10}^{-3}\mathrm{eV}.$ The result persists for nonzero thickness branes.

The possibility that the energy density of the Universe is dominated by a network of low-tension domain walls provides an alternative to the commonly discussed cosmological constant and scalar-field quintessence models of dark energy. We quantify the lower bound on the number density of the domain walls that follows from the observed near isotropy of the cosmic microwave background radiation. This bound can be satisfied by a strongly frustrated domain wall network. No fine tuning of the parameters of the underlying field theory model is required. We briefly outline the observational consequences of this model.

We derive the deflection angle up to ${O(m}^{2}a)$ due to a Kerr gravitational lens with a mass m and specific angular momentum a. It is known that at the linear order in m and a the Kerr lens is observationally equivalent to the Schwarzschild one because of the invariance under the global translation of the center of the lens mass. We show, however, that nonlinear couplings break the degeneracy so that the rotational effect becomes in principle separable for multiple images of a single source. Furthermore, it is distinguishable also for each image of an extended source and/or a point source in orbital motion. In practice, the correction at ${O(m}^{2}a)$ becomes ${O(10\mathrm{}}^{-10})$ for the supermassive black hole in our galactic center. Hence, these nonlinear gravitational lensing effects are too small to detect by near-future observations.

We report a calculation of the expected rate of inclined air showers induced by ultra high-energy cosmic rays to be obtained by the Auger Southern Observatory assuming different mass compositions. We describe some features that can be used to distinguish photons at energies as high as ${10}^{20}\mathrm{eV}.$ The discrimination of photons at such energies will help to test some models of the origin of ultrahigh-energy cosmic rays.

The recently detected polarization of the cosmic microwave background (CMB) holds the potential for revealing the physics of inflation and gravitationally mapping the large-scale structure of the universe, if so called B-mode signals below ${10}^{-7},$ or tenths of a $\mu \mathrm{K},$ can be reliably detected. We provide a language for describing systematic effects which distort the observed CMB temperature and polarization fields and so contaminate the B modes. We identify 7 types of effects, described by 11 distortion fields, and show their association with known instrumental systematics such as common mode and differential gain fluctuations, line cross-coupling, pointing errors, and differential polarized beam effects. Because of aliasing from the small-scale structure in the CMB, even uncorrelated fluctuations in these effects can affect the large-scale B modes relevant to gravitational waves. Many of these problems are greatly reduced by having an instrumental beam that resolves the primary anisotropies (full width at half maximum $\ll {10}^{\prime }).\mathrm{}$ To reach the ultimate goal of an inflationary energy scale of $3\times {10}^{15}\mathrm{GeV},$ polarization distortion fluctuations must be controlled at the ${10}^{-2}–{10}^{-3}$ level and temperature leakage to the ${10}^{-4}–{10}^{-3}$ level depending on the effect. For example, pointing errors must be controlled to ${1.5}^{″}\mathrm{rms}$ for arcminute scale beams or a percent of the Gaussian beam width for larger beams; low spatial frequency differential gain fluctuations or line cross-coupling must be eliminated at the level of ${10}^{-4}\mathrm{rms}.$

We consider the problem of searching for gravitational waves emitted during the inspiral phase of binary systems when the orbital plane precesses due to relativistic spin-orbit coupling. This effect takes place when the spins of the binary members are misaligned with respect to the orbital angular momentum. As a first step we assess the importance of precession specifically for the first generation of Laser Interferometric Gravitational Wave Observatory (LIGO) detectors. We investigate the extent of the signal-to-noise ratio reduction and, hence, detection rate that occurs when precession effects are not accounted for in the template waveforms. We restrict our analysis to binary systems that undergo the so-called simple precession and have a total mass $\lesssim {10M}_{\odot }.$ We find that for binary systems with rather high mass ratios (e.g., a ${1.4M}_{\odot }$ neutron star and a ${10M}_{\odot }$ black hole) the detection rate can decrease by almost an order of magnitude. Current astrophysical estimates of the rate of binary inspiral events suggest that LIGO could detect at most a few events per year, and therefore the reduction of the detection rate even by a factor of a few is critical. In the second part of our analysis, we examine whether the effect of precession could be included in the templates by capturing the main features of the phase modulation through a small number of extra parameters. Specifically we examine and tested for the first time the 3-parameter family suggested by Apostolatos. We find that, even though these “mimic” templates improve the detection rate, they are still inadequate in recovering the signal-to-noise ratio at the desired level. We conclude that a more complex template family is needed in the near future, still maintaining the number of additional parameters as small as possible in order to reduce the computational costs.

We calculate the $P^0\to \gamma \gamma ,$ $V^0\to P^0\gamma ,$ and $V^0\to V^{\prime 0}\gamma \gamma$ decays in the framework of a $\mathrm{U}\mathrm{}\left(3\right)\mathrm{}\otimes \mathrm{U}\mathrm{}\left(3\right)\mathrm{}$ linear sigma model which includes constituent quarks. For the first two decays this approach improves results based on the anomalous Wess-Zumino term, with contributions due to $\mathrm{SU}\mathrm{}\left(3\right)\mathrm{}$ symmetry breaking and vector mixing. The $\overrightarrow{\phi }(\omega ,\rho )\gamma \gamma$ decays are dominated by resonant ${\eta }^{\prime }$ exchange. Our calculation for the latter decays improves and updates similar calculations in the—closely related—framework of vector meson dominance. We obtain $\mathrm{BR}\left(\overrightarrow{\phi }\rho \gamma \gamma \right)=2.5\mathrm{}\times {10}^{-5}$ and $\mathrm{BR}\left(\overrightarrow{\phi }\omega \gamma \gamma \right)=2.8\mathrm{}\times {10}^{-6}$ within the scope of the high-luminosity $\phi$ factories.

We analyze the singlet P-wave charmonium production at $e^{+}{e}^{-}$ colliders within the framework of unconstrained supersymmetry. We show that the $\mathrm{CP}$-violating transitions, dominated by the gluino exchange, are typically four orders of magnitude larger than the $\mathrm{CP}$-conserving ones, and the former are generated by the electric dipole moment of the charm quark. Our results can be directly tested via the charmonium searches at the $\mathrm{CLEO}-\mathrm{C}$ experiment.

The CP-violating phases associated with Majorana neutrinos can give rise to CP-violating effects even in processes that conserve total lepton number, such as $\overrightarrow{\mu }\mathrm{ee}ē,$ $\mu \overrightarrow{e}ee,$ and others. After explaining the reasons that make this happen, we consider the calculation of the rates for a process of the form ${\mathcal{l}}_a{\mathcal{l}}_b\to {\mathcal{l}}_a{\mathcal{l}}_c$ and its conjugate ${\overline{\mathcal{l}}}_a{\overline{\mathcal{l}}}_b\to {\overline{\mathcal{l}}}_a{\overline{\mathcal{l}}}_c,$ where ${\mathcal{l}}_a,{\mathcal{l}}_b,{\mathcal{l}}_c$ denote charged leptons of different flavors. In the context of the standard model with Majorana neutrinos, we show that the difference in the rates depends on such phases. Our calculations illustrate in detail the mechanics that operate behind the scene, and set the stage for carrying out the analogous, more complicated (as we explain) calculations for other processes such as $\overrightarrow{\mu }\mathrm{ee}ē$ and its conjugate.

The constraints on the value of the Cabibbo-Kobayashi-Maskawa phase $\gamma$ that may be achieved by prospective measurements of $\sin 2\beta$ and $\sin (2\mathrm{}\beta +\gamma )$ are discussed. Significant constraints require quite small errors, and may depend on assumptions about strong phases. The measurement of $\sin (2\mathrm{}\beta +\gamma )$ combined with other experiments could provide valuable limits on new physics in $B_d-$ mixing.

We examine the potential for detecting and studying Higgs bosons at a photon-photon collider facility associated with a future linear collider. Our study incorporates realistic $\gamma \gamma$ luminosity spectra based on the most probable available laser technology. Results include detector simulations. We study the cases of (a) a standard-model-like Higgs boson, (b) the heavy minimal supersymmetric standard model Higgs bosons, and (c) a Higgs boson with no $WW/ZZ$ couplings from a general two Higgs doublet model.

A gluino in the mass range 12–16 GeV combined with a light (2–5.5 GeV) bottom squark, as has been proposed recently to explain an excess of b quark hadroproduction, would affect the momentum-scale dependence (“running”) of the strong coupling constant ${\alpha }_s$ in such a way as to raise its value at $M_Z$ by about $0.014\pm \mathrm{0.001.}$ If one combines sources of uncertainty at low ${(m}_b)$ and high ${(M}_Z)$ mass scales, one cannot exclude such a possibility. Prospects for improvement in this situation, which include better lattice QCD simulations and better measurements at $M_Z,$ are discussed.

In this paper we develop a systematic quantum field theory based approach to the vacuum replica recently found to exist in effective low-energy models in hadronic physics. A local operator creating the replica state is constructed explicitly. We show that a new effective quark-quark force arises as a result of the replica existence. The phenomenological implications of such a force are also briefly discussed.

The general formalism for the two-component description of inelastic lepton-nucleon scattering in the diffractive region is proposed. The nonperturbative contribution to electromagnetic structure functions of a nucleon is described by a modified generalized vector dominance model containing special cutoff factors restricting the phase volume of the initial $q\overline{q}$ pairs of the virtual photon’s fluctuations. The perturbative QCD contribution is described by the phenomenological model suggested (in nonunitarized form) by Forshaw, Kerley, and Shaw. The formulas needed for a numerical calculation of the photonuclear cross sections integrated over $Q^2$ are presented. It is argued that in the case of photonuclear cross sections at superhigh energies of leptons $\left(E\gtrsim {10}^5\mathrm{GeV}\right),$ integrated over $Q^2,$ the following two-component scheme is good enough: the nonperturbative contribution is approximated by the old parametrization of Bezrukov and Bugaev, and the perturbative one is described by the model of Forshaw, Kerley, and Shaw with the parameters determined from DESY data. The corresponding results of numerical calculations for the perturbative part are given, for the cases of $\mu A$ and $\tau A$ scattering at superhigh energies.

The transverse momentum $Q_T$ distribution is computed for inclusive Higgs boson production at the energy of the CERN Large Hadron Collider. We focus on the dominant gluon-gluon subprocess in perturbative quantum chromodynamics and incorporate contributions from the quark-gluon and quark-antiquark channels. Using an impact-parameter b-space formalism, we include all-orders resummation of large logarithms associated with emission of soft gluons. Our resummed results merge smoothly at large $Q_T$ with the fixed-order expectations in perturbative quantum chromodynamics, as they should, with no need for a matching procedure. They show a high degree of stability with respect to variation of parameters associated with the nonperturbative input at low $Q_T.$ We provide distributions $d\sigma {/dydQ}_T$ for Higgs boson masses from $M_Z$ to 200 GeV. The average transverse momentum at zero rapidity y grows approximately linearly with mass of the Higgs boson over the range $M_Z<m_h<200\mathrm{}\mathrm{GeV},$ $〈Q_T〉\simeq {0.18m}_h+18\mathrm{}\mathrm{GeV}.$ We provide analogous results for Z boson production, for which we compute $〈Q_T〉\simeq 25\mathrm{GeV}.$ The harder transverse momentum distribution for the Higgs boson arises because there is more soft gluon radiation in Higgs boson production than in Z production.

We review the theory of meson decays to two lepton pairs, including the cases of identical as well as nonidentical leptons, as well as CP-conserving and CP-violating couplings. A complete lowest-order calculation of QED radiative corrections to these decays is discussed, and comparisons of predicted rates and kinematic distributions between tree-level and one-loop-corrected calculations are presented for both ${\pi }^0$ and $K^0$ decays.

We derive a reduction formula that expresses the survival rate for the three-flavor neutrino oscillation using the two-flavor one to next-to-leading order when there is one resonance due to the matter effect. We numerically find that the next-to-leading reduction formula is extremely accurate and the improvement is relevant for the precision test of solar neutrino oscillation and the indirect measurment of $\mathrm{CP}$ violation in the leptonic sector. We also derive a reduction formula, which is slightly different from that previously obtained, in the case when there are two resonances. We numerically verify that this reduction formula is quite accurate and is valid for a wider parameter region than are those previously obtained.

We study a new mechanism for the electromagnetic gauging of chiral bosons showing that new possibilities emerge for the interacting theory of chiral scalars. We introduce a chirally coupled gauge field necessary to mod out the degree of freedom that obstructs gauge invariance in a system of two opposite chiral bosons soldering them together.

In this Brief Report we give the proof that the solution of any static test charge distribution in Schwarzschild space is unique. In order to give the proof we derive the first Green’s identity written with p-forms on (pseudo) Riemannian manifolds. Moreover, the proof of uniqueness can be shown for either any purely electric or purely magnetic field configuration. The spacetime geometry is not crucial for the proof.