The two body charmless decays of $B_s$ mesons to light vector mesons are analyzed within the framework of QCD factorization. This approach implies that the nonfactorizable corrections to different helicity amplitudes are not the same. The effective parameters $a_i^h$ for helicity $h=0,+,-$ states receive different nonfactorizable contributions and hence are helicity dependent, contrary to the naive factorization approach where $a_i^h$ are universal and polarization independent. The branching ratios for $B_s\to \mathrm{VV}$ decays are calculated and we find that the branching ratios of some channels are of the order of ${10}^{-5},$ which are measurable at future experiments. The transverse to total decay rate ${\Gamma }_T/\Gamma$ is also evaluated and found to be very small for most decay modes; so, in charmless $B_s\to \mathrm{VV}$ decays, both light vector mesons tend to have zero helicity.

We calculate next-to-next-to-leading order soft-gluon corrections to top quark total and differential cross sections in hadron colliders. We increase the accuracy of our previous estimates by including additional subleading terms, including next-to-next-to-next-to-leading-logarithmic and some virtual terms. We show that the kinematics dependence of the cross section vanishes near threshold and is reduced away from it. The factorization and renormalization scale dependence of the cross section is also greatly reduced. We present results for the top quark total cross sections and transverse momentum distributions at the Fermilab Tevatron and the CERN LHC.

We study the one-loop effects of charginos and neutralinos on the helicity amplitudes for $e^{+}{e}^{-}\to W^{+}{W}^{-}$ in the minimal supersymmetric standard model. The calculation is tested by using two methods. First, the sum rule for the form factors between $e^{+}{e}^{-}\to W^{+}{W}^{-}$ and the process where the external $W^{\pm }$ bosons are replaced by the corresponding Goldstone bosons ${\omega }^{\pm }$ is employed to test the analytic expression and the accuracy of the numerical program. Second, the decoupling property in the large mass limit is used to test the overall normalization of the amplitudes. These two tests are most effectively carried out when the amplitudes are expanded in terms of the modified minimal subtraction $\left(\overline{\mathrm{MS}}\right)$ couplings of the standard model. The resulting perturbation expansion is valid at collider energies below and around the threshold of the light supersymmetric particles. We find that the corrections to the cross section of the longitudinally polarized W-pair production can be as large as $-1.4\%$ at the threshold of the light chargino-pair production for large scattering angles. We also study the effects of the CP-violating phase in the chargino and neutralino sectors on the helicity amplitudes. We find that the resulting CP-violating asymmetries can be at most 0.1%.

We perform a global analysis of neutrino oscillation data in the framework of three neutrinos, including the recent improved measurement of the neutral current events at the Sudbury Neutrino Observatory. In addition to all current solar neutrino data, we take into account the reactor neutrino data from KamLAND and CHOOZ, the atmospheric neutrino data from Super-Kamiokande and MACRO, as well as the first spectral data from the K2K long baseline accelerator experiment. The up-to-date best-fit values and allowed ranges of the three-flavor oscillation parameters are determined from these data. Furthermore, we discuss in detail the status of the small parameters $\alpha \equiv \Delta m_{\mathrm{sol}}^2/\Delta m_{\mathrm{atm}}^2$ and ${\sin }^2{\theta }_{13},$ which fix the possible strength of CP-violating effects in neutrino oscillations.

We investigate the initial progenitor mass dependence of the early-phase neutrino signal from supernovae taking neutrino oscillations into account. The early-phase analysis has advantages in that it is not affected by the time evolution of the density structure of the star due to shock propagation or whether the remnant is a neutron star or a black hole. The initial mass affects the evolution of the massive star and its presupernova structure, which is important for two reasons when considering the neutrino signal. First, the density profile of the mantle affects the dynamics of neutrino oscillation in supernova. Second, the final iron core structure determines the features of the neutrino burst, i.e., the luminosity and the average energy. We find that both effects are rather small. This is desirable when we try to extract information on neutrino parameters from future supernova-neutrino observations. Although the uncertainty due to the progenitor mass is not small for intermediate ${\theta }_{13}$ ${(10\mathrm{}}^{-5}\lesssim {\sin }^{2}2{\theta }_{13}\lesssim {10}^{-3}),$ we can, nevertheless, extract information on the character of the mass hierarchy and whether ${\theta }_{13}$ is very large or very small.

We calculate the lepton electric dipole moments in a class of supersymmetric seesaw models and explore the possibility that they may provide a way to probe some of the CP violating phases responsible for the origin of matter via leptogenesis. We show that in models where the right handed neutrino masses $M_R$ arise from the breaking of local $B-L$ by a Higgs field with $B-L=2,$ some of the leptogenesis phases can lead to enhancement of the lepton dipole moments compared to the prediction of models where $M_R$ is either directly put in by hand or is a consequence of a higher dimensional operator.

The measurement of the invisible Z-boson decay width at $e^{+}{e}^{-}$ colliders can be done “indirectly,” by subtracting the Z-boson visible partial widths from the Z-boson total width, or “directly,” from the process $e^{+}{e}^{-}\to \gamma \nu \overline{\nu }.$ Both procedures are sensitive to different types of new physics and provide information about the couplings of the neutrinos to the Z boson. At present, measurements at CERN LEP and CHARM II are capable of constraining the left-handed $Z\nu \overline{\nu }$ coupling, $0.45\lesssim g_L\lesssim 0.5,$ while the right-handed one is only mildly bounded, $|g_R|<~\mathrm{0.2.}$ We show that measurements at a future $e^{+}{e}^{-}$ linear collider at different center-of-mass energies, $\sqrt{s}{=m}_Z$ and $\sqrt{s}\approx 170\mathrm{GeV},$ would translate into a markedly more precise measurement of the $Z\nu \overline{\nu }$ couplings. A statistically significant deviation from standard model predictions will point toward different new physics mechanisms, depending on whether the discrepancy appears in the direct or the indirect measurement of the invisible Z width. We discuss some scenarios which illustrate the ability of different invisible Z-boson decay measurements to constrain new physics beyond the standard model.

We discuss the physics potential of intermediate $L\sim 20–30\mathrm{km}$ baseline experiments at reactor facilities. Assuming that the solar neutrino oscillation parameters $\Delta m_{\odot }^2$ and ${\theta }_{\odot }$ lie in the high LMA solution region, we show that such an intermediate baseline reactor experiment can determine both $\Delta m_{\odot }^2$ and ${\theta }_{\odot }$ with a remarkably high precision. We perform also a detailed study of the sensitivity of the indicated experiment to $\Delta m_{\mathrm{atm}}^2,$ which drives the dominant atmospheric ${\nu }_{\mu }$ $\left({\overline{\nu }}_{\mu }\right)$ oscillations, and to θ—the neutrino mixing angle limited by the data from the CHOOZ and Palo Verde experiments. Irrespective of the actual values of $\Delta m_{\odot }^2,$ we find that this experiment can improve the bounds on ${\sin }^2\theta ,$ and, if the value of ${\sin }^2\theta$ is large enough, ${\sin }^2\theta \gtrsim 0.02,$ the energy resolution of the detector is sufficiently good and if the statistics is relatively high, it can determine with extremely high precision the value of $\Delta m_{\mathrm{atm}}^2.$ We also explore the potential of the intermediate baseline reactor neutrino experiment for determining the type of the neutrino mass spectrum, which can be with normal or inverted hierarchy, assuming $\Delta m_{\odot }^2$ to lie in the high LMA solution region. We show that the conditions under which the type of neutrino mass hierarchy can be determined are quite challenging, but are within the reach of the experiment under discussion.

We present fits to charmless hadronic B decay data from the BaBar, Belle and CLEO experiments using two theoretical models: (i) the QCD factorization model of Beneke et al. and (ii) QCD factorization complemented with the so-called charming penguin contributions of Ciuchini et al. When we include the data from pseudoscalar-vector decays the results favor the incorporation of the charming penguin terms. We also present fit results for the unitarity triangle parameters and the CP-violating asymmetries.

We report the results of a search for the decay $B^0\to e^{+}{e}^{-},$ ${\mu }^{+}{\mu }^{-}$ and $e^{\pm }{\mu }^{\mp }$ based on an analysis of $78{\mathrm{fb}}^{-1}$ of data collected by the Belle detector at KEKB. No candidate events have been found. Upper limits on the branching fractions are calculated at the 90% confidence level: $\mathcal{B}{(B}^0\to e^{+}{e}^{-})<\mathrm{}1.9\mathrm{}\times {10}^{-7},$ $\mathcal{B}{(B}^0\to {\mu }^{+}{\mu }^{-})<\mathrm{}1.6\mathrm{}\times {10}^{-7},$ and $\mathcal{B}{(B}^0\to e^{\pm }{\mu }^{\mp })<\mathrm{}1.7\mathrm{}\times {10}^{-7}.$ A limit on the Pati-Salam leptoquark mass $M_{\mathrm{LQ}}>46\mathrm{}\mathrm{TeV}{/c}^2$ is obtained at the 90% confidence level.

We give an effective field theory derivation, based on the running of Planck brane gauge correlators, of the large logarithms that arise in the predictions for low energy gauge couplings in compactified ${\mathrm{AdS}}_5$ backgrounds, including the one-loop effects of bulk scalars, fermions, and gauge bosons. In contrast with the case of charged scalars coupled to Abelian gauge fields that has been considered previously in the literature, the one-loop corrections are not dominated by a single 4D Kaluza-Klein mode. Nevertheless, in the case of gauge field loops, the amplitudes can be reorganized into a leading logarithmic contribution that is identical to the running in 4D non-Abelian gauge theory, and a term which is not logarithmically enhanced and is analogous to a two-loop effect in 4D. In a warped grand unified theory (GUT) model broken by the Higgs mechanism in the bulk, we show that the matching scale that appears in the large logarithms induced by the non-Abelian gauge fields is $m_{\mathrm{XY}}^2/k$ where $m_{\mathrm{XY}}$ is the bulk mass of the XY bosons and k is the AdS curvature. This is in contrast with the UV scale in the logarithmic contributions of scalars, which is simply the bulk mass m. Our results are summarized in a set of simple rules that can be applied to compute the leading logarithmic predictions for coupling constant relations within a given warped GUT model. We present results for both boundary breaking of the GUT gauge group and bulk breaking through the Higgs mechanism.

This work is an extension of our previous work [Phys. Rev. Lett. 89, 131601 (2002)] which showed how to systematically calculate the high energy evolution of gauge couplings in compact ${\mathrm{AdS}}_5$ (five dimensional anti–de Sitter) backgrounds. We first directly compute the one-loop effects of massive charged scalar fields on the low energy couplings of a gauge theory propagating in the AdS background. It is found that scalar bulk masses (which generically are of the order of the Planck scale) enter only logarithmically in the corrections to the tree-level gauge couplings. As we pointed out previously, we show that the large logarithms that appear in the AdS one-loop calculation can be obtained within the confines of an effective field theory, by running the Planck brane correlator from a high UV matching scale down to the TeV scale. This result exactly reproduces our previous calculation, which was based on AdS–conformal field theory duality. We also calculate the effects of scalar fields satisfying nontrivial boundary conditions (relevant for orbifold breaking of bulk symmetries) on the running of gauge couplings.

We study both analytically and numerically a coupled system of spherically symmetric SU(2) Yang-Mills-dilaton equations in 3+1 Minkowski space-time. It has been found that the system admits a hidden scale invariance which becomes transparent if a special ansatz for the dilaton field is used. This choice corresponds to a transition to a frame rotated in the $\ln r-t$ plane at a definite angle. We find an infinite countable family of self-similar solutions which can be parametrized by the N—the number of zeros of the relevant Yang-Mills (YM) function. According to the performed linear perturbation analysis, the lowest solution with $N=0\mathrm{}$ only occurred to be stable. The Cauchy problem has been solved numerically for a wide range of smooth finite-energy initial data. It has been found that if the initial data exceed some threshold, the resulting solutions in a compact region shrinking to the origin attain the lowest $N=0\mathrm{}$ stable self-similar profile, which can pretend to be a global stable attractor in the Cauchy problem. The solutions reside a finite time in a self-similar regime and then the unbounded growth of the second derivative of the YM function at the origin indicates a singularity formation, which is in agreement with the general expectations for the supercritical systems.

We examine the global structure of scalar field critical collapse spacetimes using a characteristic double-null code. It can integrate past the horizon without any coordinate problems, due to the careful choice of constraint equations used in the evolution. The limiting sequence of sub- and supercritical spacetimes presents an apparent paradox in the expected Penrose diagrams, which we address in this paper. We argue that the limiting spacetime converges pointwise to a unique limit for all $r>\mathrm{}0,$ but not uniformly. The $r=0\mathrm{}$ line is different in the two limits. We interpret that the two different Penrose diagrams differ by a discontinuous gauge transformation. We conclude that the limiting spacetime possesses a singular event, with a future removable naked singularity.

The Lorentzian Hamiltonian constraint is solved for isotropic loop quantum cosmology coupled to a massless scalar field. As in the Euclidean case, the discreteness of quantum geometry removes the classical singularity from the quantum Friedmann models. In spite of the absence of the classical singularity, a modified DeWitt initial condition is incompatible with a late-time smooth behavior. Further, the smooth behavior is recovered only for positive or negatives times but not both. An important feature, which is shared with the Euclidean case, is a minimal initial energy of the order of the Planck energy required for the system to evolve dynamically. By forming wave packets of the matter field, an explicit evolution in terms of an internal time is obtained.

In this work we establish the correspondence between solutions to the Friedmann-Robertson-Walker cosmologies for perfect fluid and scalar field sources, where both satisfy state equations of the form $p+\rho =\gamma f\left(\rho \right),$ not necessarily linear ones. Such state equations are of common use in the case of matter fluids; nevertheless, for a scalar field, they introduce relationships on the potential and kinetic scalar field energies which restrict the set of solutions. A theorem in this respect is demonstrated: From any given $3+1$ cosmological solution, obeying the quoted state equations, one can derive its $2+1$ cosmological counterpart or vice versa. Some applications are given.

Quintessence models based on a scalar field $\phi$ with an inverse power law potential display simple tracking behavior at early times, when the quintessence energy density ${\rho }_{\phi }$ is subdominant. At late times, when ${\rho }_{\phi }$ becomes comparable to the matter density ${\rho }_m,$ the evolution of $\phi$ diverges from its scaling behavior. We calculate the first-order departure of $\phi$ from its tracker solution at low redshift. Our results for the evolution of $\phi ,$ ${\rho }_{\phi },$ ${\Omega }_{\phi },$ and w are surprisingly accurate even down to $z=0.\mathrm{}$ We find that w and ${\Omega }_{\phi }$ are related linearly to first order, and derive a semianalytic expression for $w\left(z\right)\mathrm{}$ which is accurate to within a few percent. Our analytic techniques are potentially applicable to any quintessence model in which the quintessence component comes to dominate at late times.

We perform an independent foreground analysis of the Wilkinson Microwave Anisotropy Probe (WMAP) maps to produce a cleaned cosmic microwave background (CMB) map (available online) useful for cross-correlation with, e.g., galaxy and x-ray maps. We use a variant of the Tegmark-Efstathiou technique that assumes that the CMB has a blackbody spectrum, but is otherwise completely blind, making no assumptions about the CMB power spectrum, the foregrounds, WMAP detector noise or external templates. Compared with the foreground-cleaned internal linear combination map produced by the WMAP team, our map has the advantage of containing less non-CMB power (from foregrounds and detector noise) outside the Galactic plane. The difference is most important on the angular scale of the first acoustic peak and below, since our cleaned map is at the highest ${(12.6\mathrm{}}^{\prime })$ rather than lowest ${(49.2\mathrm{}}^{\prime })$ WMAP resolution. We also produce a Wiener filtered CMB map, representing our best guess as to what the CMB sky actually looks like, as well as CMB-free maps at the five WMAP frequencies useful for foreground studies. We argue that our CMB map is clean enough that the lowest multipoles can be measured without any galaxy cut, and obtain a quadrupole value that is slightly less low than that from the cut-sky WMAP team analysis. This can be understood from a map of the CMB quadrupole, which shows much of its power falling within the Galaxy cut region, seemingly coincidentally. Intriguingly, both the quadrupole and the octopole are seen to have power suppressed along a particular spatial axis, which lines up between the two, roughly towards $\mathrm{}(l,b)\mathrm{}\sim (-110°,60\mathrm{}°)$ in Virgo.

We consider the influence of the dark energy dynamics at the onset of cosmic acceleration on the cosmic microwave background (CMB) bispectrum, through the weak lensing effect induced by structure formation. We study the line of sight behavior of the contribution to the bispectrum signal at a given angular multipole l: we show that it is nonzero in a narrow interval centered at a redshift z satisfying the relation $l/r\left(z\right)\mathrm{}\simeq k_{\mathrm{NL}}\mathrm{}\left(z\right),$ where the wave number corresponds to the scale entering the nonlinear phase and r is the cosmological comoving distance. The relevant redshift interval is in the range $0.1\lesssim z\lesssim 2$ for multipoles $1000\gtrsim l\gtrsim 100;$ the signal amplitude, reflecting the perturbation dynamics, is a function of the cosmological expansion rate at those epochs, probing the dark energy equation of state redshift dependence independent of its present value. We provide a working example by considering tracking inverse power law and supergravity quintessence scenarios, having sensibly different redshift dynamics and respecting all the present observational constraints. For scenarios having the same present equation of state, we find that the effect described above induces a projection feature which makes the bispectra shifted by several tens of multipoles, about ten times more than the corresponding effect on the ordinary CMB angular power spectrum.

We provide a Wilsonian proof for the renormalizability of four-dimensional quantum field theories with $\mathcal{N}=1/2\mathrm{}$ supersymmetry. We argue that the non-Hermiticity inherent to these theories permits assigning a noncanonical scaling dimension both for the Grassman coordinates and superfields. This reassignment can be done in such a way that the non(anti)commutativity parameter is dimensionless, and then the rest of the proof amounts to power counting. The renormalizability is also stable against adding standard four-dimensional soft-breaking terms to the theory. However, with the new scaling dimension assignments, some of these terms are not just relevant deformations of the theory but become marginal.