Using the method of QCD light-cone sum rules, we calculate the $B\to \pi \pi$ hadronic matrix elements with annihilation topology. We obtain a finite result, including the related strong phase. Numerically, the annihilation effects in $B\to \pi \pi$ turn out to be small with respect to the factorizable emission mechanism. Our predictions, together with the earlier sum rule estimates of emission and penguin contributions, are used for the phenomenological analysis of $B\to \pi \pi$ channels. We predict a $\Delta I=1/2$ transition amplitude which significantly differs from this amplitude extracted from the current data.

We have investigated the invariant mass spectrum of dimuons collected by the CDF experiment during the 1992–1995 run of the Fermilab Tevatron collider to improve the limit on the existence of narrow resonances set by the experiments at the SPEAR $e^{+}{e}^{-}$ collider. In the mass range $6.3-9.0\mathrm{GeV}/{\mathrm{c}}^2$, we derive 90% upper credible limits to the ratio of the production cross section times muonic branching fraction of possible narrow resonances to that of the ${\rm Y}(1S)$ meson. In this mass range, the average limit varies from 1.7 to 0.5%. This limit is much worse at the mass of $7.2\mathrm{GeV}/{\mathrm{c}}^2$ due to an excess of $250\pm 61$ events with a width consistent with the detector resolution.

Various recent studies proved that cosmological models with a significant contribution from cold dark matter isocurvature perturbations are still compatible with most recent data on cosmic microwave background anisotropies and on the shape of the galaxy power spectrum, provided that one allows for a very blue spectrum of primordial entropy fluctuations ($n_{\mathrm{iso}}>2$). However, such models predict an excess of matter fluctuations on small scales, typically below $40h^{-1}\mathrm{Mpc}$. We show that the proper inclusion of high-resolution high signal-to-noise Lyman-$\alpha$ forest data excludes most of these models. The upper bound on the isocurvature fraction $\alpha =f_{\mathrm{iso}}^2/(1+f_{\mathrm{iso}}^2)$, defined at the pivot scale $k_0=0.05{\mathrm{Mpc}}^{-1}$, is pushed down to $\alpha <0.4$, while $n_{\mathrm{iso}}=1.9\pm 1.0$ (95% confidence limits). We also study the bounds on curvaton models characterized by maximal correlation between curvature and isocurvature modes, and a unique spectral tilt for both. We find that $f_{\mathrm{iso}}<0.05$ (95% C.L.) in that case. For double-inflation models with two massive inflatons coupled only gravitationally, the mass ratio should obey $R<3$ (95% C.L.).

We show that $\mathrm{U}(1{)}^{\prime }$ models linked with the seesaw mechanism at the TeV scale can lead to a successful baryogenesis through soft leptogenesis with a resonant behavior in the $B$ parameter. Such a consideration constrains the $Z^{\prime }$ mass to be larger than 2–3 TeV depending on the seesaw scale and the spharelon rate. Together with multi-TeV $Z^{\prime }$, large sneutrino-antisneutrino mixing and $CP$ violating phenomena required by the TeV leptogenesis could be searched for in future colliders by observing distinct same-sign dilepton–dichargino as well as dislepton-diHiggs signatures.

We propose that the low energy behavior of a pure gauge theory can be studied by simply assuming violation of Lorentz invariance which is implemented through a deformation of the canonical Poisson brackets of the theory depending on an infrared scale. The resulting theory is equivalent to a pure gauge theory with a Chern-Simons like term. It is shown that at low energies this theory can be identified with three dimensional QCD where the mass of the fermion is related to the infrared scale.

We study the fluctuations of the stress tensor for a massless scalar field in two- and four-dimensional Minkowski spacetime in the vacuum state. Covariant expressions for the stress tensor correlation function are obtained as sums of derivatives of a scalar function. These expressions allow one to express spacetime averages of the correlation function as finite integrals. We also study the correlation between measurements of the energy density along a world line. We find that these measurements may be either positively correlated or anticorrelated. The anticorrelated measurements can be interpreted as telling us that, if one measurement yields one sign for the averaged energy density, a successive measurement with a suitable time delay is likely to yield a result with the opposite sign.

Formation of fermion bag solitons is an important paradigm in the theory of hadron structure. We study this phenomenon nonperturbatively in the $1+1$ dimensional Massive Gross-Neveu model, in the large $N$ limit. We find, applying inverse-scattering techniques, that the extremal static bag configurations are reflectionless, as in the massless Gross-Neveu model. This adds to existing results of variational calculations, which used reflectionless bag profiles as trial configurations. Only reflectionless trial configurations which support a single pair of charge-conjugate bound states of the associated Dirac equation were used in those calculations, whereas the results in the present paper hold for bag configurations which support an arbitrary number of such pairs. We compute the masses of these multibound state solitons, and prove that only bag configurations which bear a single pair of bound states are stable. Each one of these configurations gives rise to an $O(2N)$ antisymmetric tensor multiplet of soliton states, as in the massless Gross-Neveu model.

We study the implications of adopting hyperbolic-driver coordinate conditions motivated by geometrical considerations. In particular, conditions that minimize the rate of change of the metric variables. We analyze the properties of the resulting system of equations and their effect when implementing excision techniques. We find that commonly used coordinate conditions lead to a characteristic structure at the excision surface where some modes are not of outflow type with respect to any excision boundary chosen inside the horizon. Thus, boundary conditions are required for these modes. Unfortunately, the specification of these conditions is a delicate issue as the outflow modes involve both gauge and main variables. As an alternative to these driver equations, we examine conditions derived from extremizing a scalar constructed from Killing’s equation and present specific numerical examples.

Precision measurements of the acoustic peaks of the cosmic microwave background indicate that neutrinos must be freely streaming at the photon decoupling epoch when $T\approx 0.3$ eV. This requirement implies restrictive limits on “secret neutrino interactions,” notably on neutrino Yukawa couplings with hypothetical low-mass (pseudo)scalars $\varphi$. For diagonal couplings in the neutrino mass basis we find $g\lesssim 1\times {10}^{-7}$, comparable to limits from supernova 1987A. For the off-diagonal couplings and assuming hierarchical neutrino masses we find $g\lesssim 1\times {10}^{-11}(0.05\mathrm{eV}/m{)}^2$ where $m$ is the heavier mass of a given neutrino pair connected by $g$. This stringent limit excludes that the flavor content of high-energy neutrinos from cosmic-ray sources is modified by $\nu \to {\nu }^{\prime }+\varphi$ decays on their way to Earth.

Inspiraling compact-object binary systems are promising gravitational wave sources for ground and space-based detectors. The time-dependent signature of these sources is a well-characterized function of a relatively small number of parameters; thus, the favored analysis technique makes use of matched filtering and maximum likelihood methods. As the parameters that characterize the source model vary, so do the templates against which the detector data are compared in the matched filter. For small variations in the parameters, the filter responses are closely correlated. Current analysis methodology samples a bank of filters whose parameter values are chosen so that the correlation between successive samples from successive filters in the bank is 97%. Correspondingly, the additional information available with each successive template evaluation is, in a real sense, only 3% of that already provided by the nearby templates. The reason for such a dense coverage of parameter space is to minimize the chance that a real signal, near the detection threshold, will be missed by the parameter space sampling. Here we investigate the use of Chebyshev interpolation for reducing the number of templates that must be evaluated to obtain the same analysis sensitivity. Additionally, rather than focus on the “loss” of signal-to-noise associated with the finite number of filters in the template bank, we evaluate the receiver operating characteristic (ROC) as a measure of the effectiveness of an analysis technique. The ROC relates the false alarm probability to the false dismissal probability of an analysis, which are the quantities that bear most directly on the effectiveness of an analysis scheme. As a demonstration, we compare the present “dense sampling” analysis methodology with the “interpolation” methodology using Chebyshev polynomials, restricted to one dimension of the multidimensional analysis problem by plotting the ROC curves. We find that the interpolated search can be arranged to have the same false alarm and false dismissal probabilities as the dense sampling strategy using 25% fewer templates. Generalized to the two-dimensional space used in the computationally limited current analyses, this suggests a factor of 2 increase in computational efficiency; generalized to the full seven-dimensional parameter space that characterizes the signal associated with an eccentric binary system of spinning neutron stars or black holes, it suggests an order of magnitude increase in computational efficiency. Since the computational cost of the analysis is driven almost exclusively by the matched filter evaluations, a reduction in the number of template evaluations translates directly into an increase in computational efficiency; additionally, since the computational cost of the analysis is large, the increased efficiency translates also into an increase in the size of the parameter space that can be analyzed and, thus, the science that can be accomplished with the data.

We give a detailed description of the differences between the factorization and results derived from SCET and QCDF for decays $B\to M_1{M}_2$. This serves as a reply to the preceding Comment. We disagree with their criticisms.

We show that the factorization formula for nonleptonic $B$ decays to two light flavor-nonsinglet mesons derived by Bauer et al. in the context of soft-collinear effective theory is equivalent to the corresponding formula in the QCD factorization approach. The apparent numerical differences in the analysis of $B\to \pi \pi$ data performed by these authors, as compared to previous QCD factorization analyses, can largely be attributed to the neglect of known perturbative and power corrections.

We study two-body $D\to PP$ decays, assuming that each decay process go through the bare amplitude followed by elastic SU(3) rescattering, where the bare amplitude consists of (i) the color-allowed and color-suppressed factorization amplitudes and (ii) the short-distance weak annihilation amplitudes. We have performed the ${\chi }^2$ fit on 14 branching ratios of $D\to PP$ decays in the formalism of the above mentioned model. The final state interactions can be well accounted for by the short-distance annihilation topologies and SU(3) rescatterings. The two SU(3) rescattering phase differences are $\delta \equiv {\delta }_{27}-{\delta }_8\simeq -46°$ and $\sigma \equiv {\delta }_{27}-{\delta }_1\simeq -21°$, where ${\delta }_{27},{\delta }_8$, and ${\delta }_1$ are the rescattering phases of final states corresponding to the representations $\mathbf{27},\mathbf{8}$, and $\mathbf{1}$, respectively. We find that the $D^0\to K^0{\overline{K}}^0$ decay occurs mainly due to the nonzero short-distance weak annihilation effects, originating from SU(3) symmetry-breaking corrections to the distribution amplitudes of the final-state kaons, but receives tiny effects from other modes via SU(3) rescattering. Our results are in remarkable accordance with the current data.

We investigate three different axial-vector form factors of the nucleon, $G_A^0$, $G_A^3$, $G_A^8$, within the framework of the SU(3) chiral quark-soliton model, emphasizing their strangeness content. We take into account the rotational $1/N_c$ and linear strange quark ($m_s$) contributions using the symmetry-conserving SU(3) quantization and assuming isospin symmetry. The strange axial-vector form factor is also obtained and they all are discussed in the context of the parity-violating scattering of polarized electrons off the nucleon and its relevance to the strange vector form factors.

Taking account of new physics and astronomy developments I give a revised high-energy neutrino flux for the active galactic nuclei core model of Stecker, Done, Salamon and Sommers.

Using results from the theory of nondegenerate conducting polymers like cis-polyacetylene, we generalize our previous work on dense baryonic matter and the soliton crystal in the massless Gross-Neveu model to finite bare fermion mass. In the large $N$ limit, the exact crystal ground state can be constructed analytically, in close analogy to the bipolaron lattice in polymers. These findings are contrasted to the standard scenario with homogeneous phases only and a first order phase transition at a critical chemical potential.

Diagnosing the core of supernova requires favor-dependent reconstruction of three species of neutrino spectra, ${\nu }_e$, ${\overline{\nu }}_e$, and ${\nu }_x$ (a collective notation for ${\nu }_{\mu }$, ${\overline{\nu }}_{\mu }$, ${\nu }_{\tau }$, and ${\overline{\nu }}_{\tau }$). We point out that, assuming the information is available, CPT symmetry can be tested with supernova neutrinos. We classify all possible level crossing patterns of neutrinos and antineutrinos into six cases and show that half of them contains only the CPT-violating mass and mixing patterns. We discuss how additional information from terrestrial experiments helps in identifying CPT violation by narrowing down the possible flux patterns. Although the method may not be a good precision test, it is particularly suited for uncovering gross violation of CPT such as different mass patterns of neutrinos and antineutrinos. The power of the method is due to the nature of the level crossing in supernova which results in the sensitivity to neutrino mass hierarchy and to the unique characteristics of in situ preparation of both $\nu$ and $\overline{\nu }$ beams. Implications of our discussion to the conventional analyses with CPT invariance are also briefly mentioned.

We study two classes of static uniform black string solutions in a $(4+1)$-dimensional SU(2) Einstein-Yang-Mills model. These configurations possess a regular event horizon and correspond in a four-dimensional picture to axially symmetric black hole solutions in an Einstein-Yang-Mills-Higgs-U(1)-dilaton theory. In this approach, one set of solutions possesses a nonzero magnetic charge, while the other solutions represent black holes located in between a monopole-antimonopole pair. A detailed analysis of the solutions’ properties is presented, the domain of existence of the black strings being determined. New four-dimensional solutions are found by boosting the five-dimensional configurations. We also present an argument for the nonexistence of finite mass hyperspherically symmetric black holes in SU(2) Einstein-Yang-Mills theory.

An identity is derived from the Einstein equation for any hypersurface $\mathcal{H}$ which can be foliated by spacelike two-dimensional surfaces. In the case where the hypersurface is null, this identity coincides with the two-dimensional Navier-Stokes-like equation obtained by Damour in the membrane approach to a black hole event horizon. In the case where $\mathcal{H}$ is spacelike or null and the 2-surfaces are marginally trapped, this identity applies to Hayward’s trapping horizons and to the related dynamical horizons recently introduced by Ashtekar and Krishnan. The identity involves a normal fundamental form (normal connection 1-form) of the 2-surface, which can be viewed as a generalization to non-null hypersurfaces of the Hajicek 1-form used by Damour. This 1-form is also used to define the angular momentum of the horizon. The generalized Damour-Navier-Stokes equation leads then to a simple evolution equation for the angular momentum.

We study the island universe model, in which initially the universe is in a cosmological constant sea, then the local quantum fluctuations violating the null energy condition create the islands of matter, some of which might correspond to our observable universe. We examine the possibility that the island universe model is regarded as an alternative scenario of the origin of observable universe.