An efficient algorithm is presented for the identification of short bursts of gravitational radiation in the data from broadband interferometric detectors. The algorithm consists of three steps: pixels of the time-frequency representation of the data that have power above a fixed threshold are first identified, clusters of such pixels that conform to a set of rules on their size and their proximity to other clusters are formed, and a final threshold is applied on the power integrated over all pixels in such clusters. Formal arguments are given to support the conjecture that this algorithm is very efficient for a wide class of signals. A precise model for the false alarm rate of this algorithm is presented, and it is shown using a number of representative numerical simulations to be accurate at the 1% level for most values of the parameters, with maximal error around 10%.

We derive and study optimal and nearly optimal strategies for the detection of sinusoidal signals hidden in additive (Gaussian and non-Gaussian) noise. Such strategies are an essential part of algorithms for the detection of the gravitational continuous wave (cw) signals produced by pulsars. Optimal strategies are derived for the case where the signal phase is not known and the product of the signal frequency and the observation time is nonintegral.

We investigate the decoupling properties of the Higgs-sector-induced one-loop corrections in the lightest Higgs-boson self-couplings, in the framework of the minimal supersymmetric standard model (MSSM). The renormalized n-point vertex functions with external Higgs particles in the $\mathrm{MSSM}$ and in the $\mathrm{SM}$ are derived to the one-loop level and compared in the $M_{A^0}\gg M_Z$ limit. The computation has been done in a general $R_{\xi }$ gauge and the on-shell renormalization scheme is chosen. By a comparison of the renormalized lightest Higgs-boson $h^0$ vertex functions with respect to the corresponding $\mathrm{SM}$ ones, we find that the differences between the predictions of both models are summarized in the lightest Higgs-boson mass correction $\Delta M_{h^0}.$ Consequently, the radiative corrections are absorbed in the Higgs-boson mass, and the trilinear and quartic $h^0$ self-couplings acquire the same structure as the couplings of the $\mathrm{SM}$ Higgs boson. Therefore, decoupling of the heavy $\mathrm{MSSM}$ Higgs bosons occurs and the MSSM $h^0$ self-interactions converge to the $\mathrm{SM}$ ones in the $M_{A^0}\gg M_Z$ limit.

We discuss the production of the composite Higgs boson in top-color models via the gluon fusion process. We consider the contribution of color-octet massive gauge bosons (colorons) strongly interacting with the top quark, in addition to nonstandard contributions of the top-Yukawa coupling and heavy colored fermions other than the top quark. In order to estimate the contribution of colorons, we derive the low-energy effective theory by eliminating colorons by using the equation of motion for colorons. We replace the composite operator $\left(q_L{t}_R\right)\left(t_R{q}_L\right)$ in the effective theory by the composite Higgs operator. We then obtain the effective gluon-gluon-Higgs $\mathrm{}\left(\mathrm{ggH}\right)\mathrm{}$ operator induced by colorons and find that its coefficient $\left({\mathcal{A}}_{\mathrm{col}}\right)$ is proportional to $m_{\mathrm{dyn}}^2{/M}^2,$ where M and $m_{\mathrm{dyn}}$ denote the coloron mass and the mass dynamically generated by colorons, respectively. The contribution of colorons ${\mathcal{A}}_{\mathrm{col}}$ becomes comparable to the top-loop effect ${\mathcal{A}}_{\mathrm{top}}$ for $M\sim \mathcal{O}\left(1\mathrm{}\mathrm{TeV}\right)$ and $m_{\mathrm{dyn}}\sim \mathcal{O}\left(0.6\mathrm{}\mathrm{TeV}\right).\mathrm{}$ Such a large dynamical mass can be realized in top-seesaw (TSS) models consistently with the experimental value of the top quark mass ${(m}_t^{\left(\exp \right)}),$ while the dynamical mass itself is adjusted to $m_t^{\left(\exp \right)}$ in top-color assisted technicolor models (TC2). We find that the coloron contribution ${\mathcal{A}}_{\mathrm{col}}$ can be sizable in a certain class of TSS models: the contribution of colorons (the top loop) is dominant in the real (imaginary) part of the $\overrightarrow{H}\mathrm{gg}$ amplitude for the Higgs boson mass $m_H$ of the order of 1 TeV. On the other hand, enhancement of the top-Yukawa coupling becomes important in TC2. We can observe signatures of the Higgs boson in TC2 with $m_H\sim 200\mathrm{GeV}$ even at the Fermilab Tevatron run II as well as at the CERN LHC. We estimate $S/\sqrt{B}=3\mathrm{}–6$ for an integrated luminosity of $2{\mathrm{fb}}^{-1}$ and $m_H=190\mathrm{}\mathrm{GeV}$ at the Tevatron run II.

We investigate spectral functions extracted using the maximum entropy method from correlators measured in lattice simulations of the $\mathrm{}(2+1)\mathrm{}$-dimensional four-fermion model. This model is particularly interesting because it has both a chirally broken phase with a rich spectrum of mesonic bound states and a symmetric phase where there are only resonances. In the broken phase we study the elementary fermion, pion, sigma, and massive pseudoscalar meson; our results confirm the Goldstone nature of the $\pi$ and permit an estimate of the meson binding energy. We have, however, seen no signal of $\overrightarrow{\sigma }\pi \pi$ decay as the chiral limit is approached. In the symmetric phase we observe a resonance of nonzero width in qualitative agreement with analytic expectations; in addition the ultraviolet behavior of the spectral functions is consistent with the large nonperturbative anomalous dimension for fermion composite operators expected in this model.

We report the first investigation of the QCD transition temperature $T_c$ for two flavors of staggered quarks with unequal masses at lattice spacings of $1/4T.$ On changing the $u/d$ quark mass ratio in such a way that $m_{{\pi }^0}^2{/m}_{{\pi }^{\pm }}^2$ changes from 1 to 0.78, thus bracketing the physical value of this ratio, we find that $T_c$ remains unchanged in units of both $m_{\rho }$ and ${\Lambda }_{\overline{\mathrm{MS}}}.$

Using the infrared dispersion relation of the on-shell gluon, we calculate the renormalization of the anisotropy, χ, to one loop in perturbation theory for lattice Yang-Mills theories, including the Wilson action and actions with Symanzik and/or tadpole improvement. Using twisted boundary conditions as a gauge invariant infrared regulator, we show for an SU(3) gauge group in $D=3+1\mathrm{}$ dimensions that the one loop anisotropy is accurate to $O(3\%)\mathrm{}$ for a range of $g^2$ and $\chi$ covering current simulations. In doing so we also present Feynman rules for $\mathrm{SU}\mathrm{}\left(N\right)\mathrm{}$ gauge groups with generic anisotropy structure (including “3+1” and “2+2” cases) for both twisted and untwisted boundary conditions.

The two-dimensional $N=2\mathrm{}$ Wess-Zumino model is constructed on the lattice through Nicolai mapping with a Ginsparg-Wilson fermion. The Nicolai mapping requires a certain would-be surface term in the bosonic action which ensures the vacuum energy cancellation even on the lattice, but inevitably breaks chiral symmetry. With the Ginsparg-Wilson fermion, the holomorphic structure of the would-be surface term is maintained, leaving a discrete subgroup of the exact chiral symmetry intact for a monomial scalar potential. Through this feature both the boson and fermion can be kept massless on the lattice without any fine-tuning.

We extend to quenched QCD an earlier investigation of the chiral structure of the masses of the nucleon and the delta in lattice simulations of full QCD. Even after including the meson-loop self-energies which give rise to the leading and next-to-leading nonanalytic behavior (and hence the most rapid variation in the region of light quark mass), we find surprisingly little curvature in the quenched case. Replacing these meson-loop self-energies by the corresponding terms in full QCD yields a remarkable level of agreement with the results of the full QCD simulations. This comparison leads to a very good understanding of the origins of the mass splitting between these baryons.

We investigate the use of long distance regularization in $\mathrm{SU}\left(3\right)\mathrm{}$ baryon chiral perturbation theory with decuplet fields. The one-loop decuplet contributions to the octet baryon masses, axial-vector couplings, S-wave nonleptonic hyperon decays and magnetic moments are evaluated in a chirally consistent fashion by employing a cutoff to implement long distance regularization. The convergence of the chiral expansions of these quantities is improved compared to the dimensionally regularized version which indicates that the propagation of Goldstone bosons over distances smaller than a typical hadronic size, which is beyond the regime of chiral perturbation theory but included by dimensional regularization, is removed by use of a cutoff.

We present the perturbative and non-perturbative QCD structure of the dipole-dipole scattering amplitude in momentum space. The perturbative contribution is described by the two-gluon exchange and the non-perturbative contribution by the stochastic vacuum model which leads to confinement of the quark and antiquark in the dipole via a string of color fields. This QCD string gives important nonperturbative contributions to high-energy reactions. A new structure different from the perturbative dipole factors is found in the string-string scattering amplitude. The string can be represented as an integral over stringless dipoles with a given dipole number density. This decomposition of the QCD string into dipoles allows us to calculate the unintegrated gluon distribution of hadrons and photons from the dipole-hadron and dipole-photon cross section via $|k_{\perp }|$ factorization.

We study the exclusive decays of $\overrightarrow{B}{K}^{\left(*\right)}{\mathcal{l}}^{+}{\mathcal{l}}^{-}$ by results in perturbative QCD with the heavy quark effective theory and lattice calculations. We obtain the form factors for the $\overrightarrow{B}{K}^{\left(*\right)}$ transitions in the whole allowed region. Our predictions for the branching ratios of $\overrightarrow{B}K{\mathcal{l}}^{+}{\mathcal{l}}^{-},$ $\overrightarrow{B}{K}^{*}{e}^{+}{e}^{-},$ and $\overrightarrow{B}{K}^{*}{\mu }^{+}{\mu }^{-}$ are $0.53\pm {0.05}_{-0.07}^{+0.10\mathrm{}},$ $1.68\pm {0.17}_{-0.09}^{+0.14\mathrm{}},$ and $1.34\pm {0.13}_{-0.06}^{+0.11\mathrm{}}\times {10}^{-6},$ where the errors are from the quark mixing elements and hadronic effects, respectively. We also find that our definitions of the T-odd observable and the up-down asymmetry of the K meson in $\overrightarrow{B}{K}^{*}{\mathcal{l}}^{+}{\mathcal{l}}^{-}\to K\pi {\mathcal{l}}^{+}{\mathcal{l}}^{-}$ can be used to probe new physics.

The measurement of the mixing angle ${\theta }_{13},$ sign of $\Delta m_{13}^2,$ and the $\mathrm{CP}$ or T violating phase $\delta$ is fraught with ambiguities in neutrino oscillation. In this paper we give an analytic treatment of the paramater degeneracies associated with measuring the ${\nu }_{\mu }\to {\nu }_e$ probability and its $\mathrm{CP}$ and/or T conjugates. For $\mathrm{CP}$ violation, we give explicit solutions to allow us to obtain the regions where there exist twofold and fourfold degeneracies. We calculate the fractional differences, $(\Delta \theta /\overline{\theta }),$ between the allowed solutions which may be used to compare with the expected sensitivities of the experiments. For T violation we show that there is always a complete degeneracy between solutions with positive and negative $\Delta m_{13}^2$ which arises due to a symmetry and cannot be removed by observing one neutrino oscillation probability and its T conjugate. Thus there is always a fourfold parameter degeneracy apart from exceptional points. Explicit solutions are also given and the fractional differences are computed. The biprobability $CP/T$ trajectory diagrams are extensively used to illuminate the nature of the degeneracies.

We investigate the possibility that the universal Yukawa coupling (democratic mass matrix) with small violations of Dirac and Majorana neutrinos can induce the large mixing of neutrinos through the seesaw mechanism. The possibility can be produced by the condition that the violation parameters of Majorana neutrinos are sufficiently smaller than the violation parameters of Dirac neutrinos. The allowed regions of the violation parameters producing the observed neutrino mass hierarchy and large neutrino mixing are not so restricted at present in contrast with the violation parameters for the quark sector. In order to obtain the distinctive features in the violation parameters for the neutrino sector as a quark sector, one should take more precise data concerned with the neutrino, for example, mass values, mixing parameters of $U_{\mathrm{MNS}},$ and $\mathrm{CP}$ violation phases.

Assuming that neutrinos are Majorana particles, in a three-generation framework, current and future neutrino oscillation experiments can determine six out of the nine parameters which fully describe the structure of the neutrino mass matrix. We try to clarify the interplay among the remaining parameters, the absolute neutrino mass scale and two $\mathrm{CP}$ violating Majorana phases, and how they can be accessed by future neutrinoless double beta $\left(0\mathrm{}\nu \beta \beta \right)$ decay experiments, for the normal as well as for the inverted order of the neutrino mass spectrum. Assuming the oscillation parameters to be in the range presently allowed by atmospheric, solar, reactor, and accelerator neutrino experiments, we quantitatively estimate the bounds on $m_0,$ the lightest neutrino mass, that can be inferred if the next generation $0\nu \beta \beta$ decay experiments can probe the effective Majorana mass ${(m}_{\mathrm{ee}})$ down to $\sim 1\mathrm{meV}.$ In this context we conclude that in the case that neutrinos are Majorana particles, (a) if $m_0\gtrsim 300\mathrm{meV},$ i.e., within the range directly attainable by future laboratory experiments as well as astrophysical observations, then $m_{\mathrm{ee}}\gtrsim 30\mathrm{meV}$ must be observed, (b) if $m_0<300\mathrm{}\mathrm{meV},$ results from future $0\nu \beta \beta$ decay experiments combined with stringent bounds on the neutrino oscillation parameters, especially the solar ones, will place much stronger limits on the allowed values of $m_0$ than these direct experiments. For instance, if a positive signal is observed around $m_{\mathrm{ee}}=10\mathrm{}\mathrm{meV},$ we estimate $3\lesssim m_0/\mathrm{meV}\lesssim 65$ at $95\%$ C.L.; on the other hand, if no signal is observed down to $m_{\mathrm{ee}}=10\mathrm{}\mathrm{meV},$ then $m_0\lesssim 55\mathrm{meV}$ at $95\%$ C.L.

A global analysis of spin flavor precession (SFP) solutions to the solar neutrino problem is given, taking into account the impact of the full set of latest solar neutrino data, including the recent SNO data and the 1496-day Super-Kamiokande data. These are characterized by three effective parameters: $\Delta m_{\mathrm{SOL}}^2\equiv \Delta m^2,$ the neutrino mixing angle ${\theta }_{\mathrm{SOL}}\equiv \theta ,$ and the magnetic field parameter $\mu B_{\perp }.$ For the last we adopt a self-consistent magnetohydrodynamics field profile in the convective zone and identify an optimum $B_{\perp }\sim 80\mathrm{kG}$ strength for $\mu {=10\mathrm{}}^{-11}{\mu }_B.$ We find that no low mass (LOW) quasivacuum or vacuum solutions are present at $3\sigma .$ In addition to the standard large mixing angle (LMA) oscillation solution, there are two SFP solutions, in the resonant (RSFP) and nonresonant (NRSFP) regimes. These two SFP solutions have a goodness of fit of 84% (RSFP) and 83% (NRSFP), slightly better than the LMA oscillation solution (78%). We discuss the role of solar antineutrino searches in the fit and present a table of best-fit parameters and ${\chi }_{\min }^2$ values. Should the KamLAND experiment confirm the LMA solution, the SFP solutions may at best be present at a subleading level, leading to a constraint on $\mu B_{\perp }.$ In the event the LMA is not the solution realized in nature, then experiments such as Borexino can help in distinguishing the LMA solution from the NRSFP solution and the simplest RSFP solution with no mixing.

Using $29.1{\mathrm{fb}}^{-1}$ of data accumulated at the ${\rm Y}\mathrm{}\left(4S\right)\mathrm{}$ with the Belle detector at KEKB, we have studied the decay modes $B^0\to {\Lambda }_c^{+}\overline{p}{\pi }^{+}{\pi }^{-},$ $B^{-}\to {\Lambda }_c^{+}\overline{p}{\pi }^{-},$ and $B^0\to {\Lambda }_c^{+}\overline{p}.$ We report branching fractions of exclusive B decays to charmed baryons with four-, three- and two-body final states, including intermediate ${\Sigma }_c^{++}$ and ${\Sigma }_c^0$ states. We observed $B^0\to {\Sigma }_c{\mathrm{}\left(2455\right)\mathrm{}}^{++}\overline{p}{\pi }^{-}$ for the first time with a branching fraction of ${(2.38\mathrm{}}_{-0.55}^{+0.63\mathrm{}}\pm 0.41\pm 0.62)\times {10}^{-4}$ and observed evidence for the two-body decay $B^{-}\to {\Sigma }_c{\mathrm{}\left(2455\right)\mathrm{}}^0\overline{p}$ with a branching fraction of ${(0.45\mathrm{}}_{-0.19}^{+0.26\mathrm{}}\pm 0.07\pm 0.12)\times {10}^{-4}.$ We also set improved upper limits for the two-body decays $B^0\to {\Lambda }_c^{+}\overline{p}$ and $B^{-}\to {\Sigma }_c{\mathrm{}\left(2520\right)\mathrm{}}^0\overline{p}.$

Using data collected by the CLEO detector in the ${\rm Y}\mathrm{}\left(4S\right)\mathrm{}$ region, we report new measurements of the exclusive decays of B mesons into final states of the type ${\Lambda }_c^{+}\overline{p}n\left(\pi \right),$ where $n=0,1,2,3.\mathrm{}$ We find signals in modes with one, two and three pions and an upper limit for the two-body decay ${\Lambda }_c^{+}\overline{p}.$ We also make the first measurements of exclusive decays of B mesons to ${\Sigma }_c\overline{p}n\left(\pi \right),$ where $n=0,1,2.\mathrm{}$ We find signals in modes with one and two pions and an upper limit for the two-body decay ${\Sigma }_c\overline{p}.$ Measurements of these modes shed light on the mechanisms involved in B decays to baryons.

Monte Carlo simulations of a system whose action has an imaginary part are considered to be extremely difficult. We propose a new approach to this “complex-action problem,” which utilizes a factorization property of distribution functions. The basic idea is quite general, and it removes the so-called overlap problem completely. Here we apply the method to a nonperturbative study of superstring theory using its matrix formulation. In this particular example, the distribution function turns out to be positive definite, which allows us to reduce the problem even further. Our numerical results suggest an intuitive explanation for the dynamical generation of 4D space-time.

We study the superalgebra of the M theory on a fully supersymmetric pp wave. We identify the algebra as the special unitary Lie superalgebra, $\mathrm{su}(2\mathrm{}|4;2,0)$ or $\mathrm{su}(2\mathrm{}|4;2,4),$ and analyze its root structure. We discuss the typical and atypical representations deriving the typicality condition explicitly in terms of the energy and other four quantum numbers. We classify the BPS multiplets preserving 4, 8, 12, 16 real supercharges and obtain the corresponding spectrum. We show that in the BPS multiplet either the lowest energy floor is an $\mathrm{su}\mathrm{}\left(2\right)\mathrm{}$ singlet or the highest energy floor is an $\mathrm{su}\mathrm{}\left(4\right)\mathrm{}$ singlet.