We investigate the weak nonleptonic decays of charm baryons emitting scalar mesons employing the factorization scheme and predict their branching ratios.

We compute corrections to precision electroweak observables in supersymmetry in the limit that scalar superpartners are very massive and decoupled. This leaves charginos and neutralinos and a standard model-like Higgs boson as the only states with unknown mass substantially affecting the analysis. We give complete formulas for the chargino and neutralino contributions, derive simple analytic results for the pure gaugino and Higgsino cases, and study the general case. We find that in all circumstances, the precision electroweak fit improves when the charginos and neutralinos are near the current direct limits. Larger Higgsino and gaugino masses worsen the fit as the theory predictions asymptotically approach those of the standard model. Since the standard model is considered by most to be an adequate fit to the precision electroweak data, an important corollary to our analysis is that all regions of parameter space allowed by direct collider constraints are also allowed by precision electroweak constraints in split supersymmetry.

This paper presents a strategy for measuring ${sin}^2{\theta }_W$ to $\sim 1\%$ at a reactor-based experiment, using $\overline{\nu }e$ elastic scattering. This error is comparable to the NuTeV, SLAC E158, and atomic parity violation results on ${sin}^2{\theta }_W$, but with substantially different systematic contributions. The measurement can be performed using the near detector of the presently proposed reactor-based oscillation experiments. We conclude that an absolute error of $\sim \delta ({\sin }^2{\theta }_W)=0.0019$ may be achieved.

We derive renormalization group equations for neutrino masses, leptonic mixing angles and $CP$-violating phases running at energies above the seesaw threshold, both in the standard model and in the minimal supersymmetric standard model extended with three right-handed neutrinos. With these equations, we carry out a systematic study of the radiative correction that may arise to neutrino parameters, via their renormalization group evolution from the electroweak scale ($M_Z$) to the scale of grand unified theories (${\Lambda }_{\mathrm{GUT}}$). We study in detail three typically interesting neutrino mass patterns: normal hierarchy, near degeneracy and inverted hierarchy. Magnitudes of possible corrections in each case are carefully investigated. We also emphasize the significance of $CP$-violating phases in controlling the evolution behavior of all neutrino parameters.

We report results of a search for the charmless two-body baryonic decays $B^0\to p\overline{p}$, $B^0\to \Lambda \overline{\Lambda }$, and $B^{+}\to p\overline{\Lambda }$ based on the analysis of a $140{\mathrm{fb}}^{-1}$ data sample. We set 90% confidence level upper limits on their branching fractions: $\mathcal{B}(B^0\to p\overline{p})<4.1\times {10}^{-7}$, $\mathcal{B}(B^0\to \Lambda \overline{\Lambda })<6.9\times {10}^{-7}$, and $\mathcal{B}(B^{+}\to p\overline{\Lambda })<4.9\times {10}^{-7}$.

We present data-analysis schemes and results of observations with the TAMA300 gravitational wave detector, targeting burst signals from stellar-core collapse events. In analyses for burst gravitational waves, the detection and fake-reduction schemes are different from well-investigated ones for a chirp wave analysis, because precise waveform templates are not available. We used an excess -power filter for the extraction of gravitational wave candidates, and developed two methods for the reduction of fake events caused by nonstationary noises of the detector. These analysis schemes were applied to real data from the TAMA300 interferometric gravitational wave detector. As a result, fake events were reduced by a factor of about 1000 in the best cases. In addition, in order to interpret the event candidates from an astronomical viewpoint, we performed a Monte-Carlo simulation with an assumed Galactic event distribution model and with burst waveforms obtained from numerical simulations of stellar-core collapses. We set an upper limit of $5.0\times {10}^3\mathrm{events}/\sec $ on the burst gravitational wave event rate in our Galaxy with a confidence level of 90%. This work shows prospects on the search for burst gravitational waves, by establishing an analysis scheme for the observation data from an interferometric gravitational wave detector.

We study the propagation of neutrinos in gravitational fields using wave functions that are exact to first order in the metric deviation. For illustrative purposes, the geometrical background is represented by the Lense-Thirring metric. We derive explicit expressions for neutrino deflection, helicity transitions, flavor oscillations, and oscillation Hamiltonian.

The ultraviolet asymptotic behavior of the gluon propagator is evaluated in the maximal Abelian gauge in the $SU(2)$ gauge theory on the basis of the renormalization-group improved perturbation theory at the one-loop level. Square-root singularities obtained in the Euclidean domain are attributed to artifacts of the one-loop approximation in the maximal Abelian gauge and the standard normalization condition for the propagator used in our study. It is argued that this gauge is essentially nonperturbative.

Using post-Newtonian equations of motion for fluid bodies that include radiation-reaction terms at 2.5 and 3.5 post-Newtonian (PN) order ($O[(v/c{)}^5]$ and $O[(v/c{)}^7]$ beyond Newtonian order), we derive the equations of motion for binary systems with spinning bodies. In particular we determine the effects of radiation reaction coupled to spin-orbit effects on the two-body equations of motion, and on the evolution of the spins. For a suitable definition of spin, we reproduce the standard equations of motion and spin-precession at the first post-Newtonian order. At 3.5 PN order, we determine the spin-orbit induced reaction effects on the orbital motion, but we find that radiation damping has no effect on either the magnitude or the direction of the spins. Using the equations of motion, we find that the loss of total energy and total angular momentum induced by spin-orbit effects precisely balances the radiative flux of those quantities calculated by Kidder et al. The equations of motion may be useful for evolving inspiraling orbits of compact spinning binaries.

We discuss a Randall-Sundrum-type two D-braneworld model in which D-branes possess different values of the tensions from those of the charges, and derive an effective gravitational equation on the branes. As a consequence, the Einstein-Maxwell theory is realized together with the nonzero cosmological constant. Here an interesting point is that the effective gravitational constant is proportional to the cosmological constant. If the distance between two D-branes is appropriately tuned, the cosmological constant can have a consistent value with the current observations. From this result we see that, in our model, the presence of the cosmological constant is naturally explained by the presence of the effective gravitational coupling of the Maxwell field on the D-brane.

Optimizing the major next-generation cosmological surveys (such as SNAP, KAOS, etc.) is a key problem given our ignorance of the physics underlying cosmic acceleration and the plethora of surveys planned. We propose a Bayesian design framework which (1) maximizes the discrimination power of a survey without assuming any underlying dark-energy model, (2) finds the best niche survey geometry given current data and future competing experiments, (3) maximizes the cross section for serendipitous discoveries and (4) can be adapted to answer specific questions (such as “is dark energy dynamical?”). Integrated parameter-space optimization (IPSO) is a design framework that integrates projected parameter errors over an entire dark energy parameter space and then extremizes a figure of merit (such as Shannon entropy gain which we show is stable to off-diagonal covariance matrix perturbations) as a function of survey parameters using analytical, grid or MCMC techniques. We discuss examples where the optimization can be performed analytically. IPSO is thus a general, model-independent and scalable framework that allows us to appropriately use prior information to design the best possible surveys.

The fluxes of light antinuclei $A\le 4$ induced near Earth by cosmic ray interactions with the interstellar matter in the Galaxy and with the Earth’s atmosphere are calculated in a phenomenological framework. The hadronic production cross section for antinucleons is based on a recent parametrization of a wide set of accelerator data. The production of light nuclei is calculated using coalescence models. For the standard coalescence model, the coalescence radius is fitted to the available experimental data. The nonannihilating inelastic scattering process for the antideuterons is discussed and taken into account for the first time via a more realistic procedure than used so far for antiprotons.

We discuss the fermion couplings in a four dimensional SU(2) linear moose model by allowing for direct couplings between the left-handed fermions on the boundary and the gauge fields in the internal sites. This is realized by means of a product of nonlinear $\sigma$-model scalar fields which, in the continuum limit, is equivalent to a Wilson line. The effect of these new nonlocal couplings is a contribution to the ${ϵ}_3$ parameter which can be of opposite sign with respect to the one coming from the gauge fields along the string. Therefore, with some fine-tuning, it is possible to satisfy the constraints from the electroweak data.

For very large values of $\tan \beta$, the charged Higgs boson pair production via $b\overline{b}$ annihilation can proceed dominantly at the large hadron collider (LHC). We calculated the cross sections of the charged Higgs boson pair production via subprocess $b\overline{b}\to H^{+}{H}^{-}$ at the LHC including the next-to-leading order (NLO) QCD corrections in the minimal supersymmetric standard model (MSSM). We find that the NLO QCD corrections can significantly reduce the dependence of the cross sections on the renormalization and factorization scales.

The confining and topological properties of the compact Abelian Higgs model with doubly-charged Higgs field in three space-time dimensions are studied. We consider the London limit of the model. We show that the monopoles are forming chainlike structures (kept together by Abrikosov-Nielsen-Olesen vortices), the presence of which is essential for getting simultaneously permanent confinement of singly-charged particles and breaking of the string spanned between doubly-charged particles. In the confinement phase, the chains are forming percolating clusters, while in the deconfinement (Higgs) phase, the chains are of finite size. The described picture is in close analogy with the synthesis of the Abelian monopole and the center vortex pictures in confining non-Abelian gauge models. The screening properties of the vacuum are studied by means of the photon propagator in the Landau gauge.

We investigate the phase diagram of strange quark matter in beta equilibrium where the lighter up and down quarks form the two flavor superconducting matter whereas the strange quark remains unpaired. This is studied wihin a Nambu-Jona-Lasinio model. The variational method as used here allows us to investigate simultaneous formation of condensates in quark-antiquark as well as in diquark channels. Color and electric charge neutrality conditions are imposed in the calculation of the thermodynamic potential. Medium dependence of strange quark mass plays a sensitive role in maintaining charge neutrality conditions. At zero temperature the system goes from the gapless phase to the usual BCS phase through an intermediate normal phase as density is increased. However, at higher temperature the gapless to BCS transition becomes a smooth transition. The gapless modes show a smooth behavior with respect to temperature vanishing above a critical temperature which is larger than the BCS transition temperature.

The equations describing the adiabatic, small radial oscillations of general relativistic stars are generalized to include the effects of a cosmological constant. The generalized eigenvalue equation for the normal modes is used to study the changes in the stability of the homogeneous sphere induced by the presence of the cosmological constant. The variation of the critical adiabatic index as a function of the central pressure is studied numerically for different trial functions. The presence of a large cosmological constant significantly increases the value of the critical adiabatic index. The dynamical stability condition of the homogeneous star in the Schwarzschild–de Sitter geometry is obtained and several bounds on the maximum allowable value for a cosmological constant are derived from stability considerations.

Electroweak corrections associated with the instability of the top quark to the next-to-next-to-leading logarithmic (NNLL) total top pair threshold cross section in $e^{+}{e}^{-}$ annihilation are determined. Our method is based on absorptive parts in electroweak matching conditions of the operators of nonrelativistic QCD and the optical theorem. The corrections lead to ultraviolet phase space divergences that have to be renormalized and lead to NLL mixing effects. Numerically, the corrections can amount to several percent and are comparable to the known NNLL QCD corrections.

We examine backreaction of quantum massive fields on multiply-degenerate (ultraextremal) horizons. It is shown that, under influence of the quantum backreaction, the horizon of such a kind moves to a new position near which the metric does not change its asymptotics, so the ultraextremal black holes and cosmological spacetimes do exist as self-consistent solutions of the semiclassical field equations.

In this note, we discuss a formula obtained recently in order to compute transient effects for photon production by a short-lived quark-gluon plasma. This discussion is based on a variation of the standard $S$-matrix approach, and allows us to point out the unrealistic assumptions needed in order to obtain this formula. We conclude that the large transient effects predicted within this framework are unphysical.