In consistency with $\overline{B}\to D^{\left(*\right)}\pi ,$ $J/\psi \overline{K},$ and $J/\psi \pi$ decays, recently observed $B^0\to D_s^{+}{\pi }^{-}$ and $B^0\to D_s^{+}{K}^{-}$ decays are studied in a hybrid perspective in which their amplitude is given by a sum of factorizable and nonfactorizable ones.

The Bethe-Salpeter equation in noncommutative QED is considered for a three body bound state. We study the nonrelativistic limit of this equation in the instantaneous approximation and derive the corresponding Schrödinger equation in noncommutative space. It is shown that the experimental data for a helium atom put an upper bound on the magnitude of the parameter of noncommutativity, $\theta \sim {10}^{-9}{\lambda }_e^2.$

We present a method to measure the weak phase $\gamma$ in the three-body decay of charged $B^{\pm }$ mesons to the final states ${\mathrm{DK}}^{\pm }{\pi }^0.$ These decays are mediated by interfering amplitudes which are color allowed and hence relatively large. As a result, large CP violation effects that could be observed with high statistical significance are possible. In addition, the three-body decay helps resolve discrete ambiguities that are usually present in measurements of the weak phase. The experimental implications of conducting these measurements with three-body decays are discussed, and the sensitivity of the method is evaluated using a simulation.

Inspired by a large decay branching ratio (BR) of $B^{+}\to f_0{\mathrm{}\left(980\right)K}^{+}$ measured by Belle recently, we propose that significant evidence of the component of $n\mathrm{n̄}=(uū+d\overline{d})/\sqrt{2}$ in $f_0\mathrm{}\left(980\right)\mathrm{}$ could be demonstrated in exclusive $\overrightarrow{b}c$ decays by the observation of $f_0\mathrm{}\left(980\right)\mathrm{}$ in the final states $\overline{B}\to D^{0\left(*\right)}{\pi }^{+}{\pi }^{-}\mathrm{}\left(\mathrm{KK}\right)\mathrm{}$ and $\overline{B}\to J/\psi {\pi }^{+}{\pi }^{-}\mathrm{}\left(\mathrm{KK}\right).$ We predict the BRs of $\overline{B}\to D^{0\left(*\right)}(J/\psi {)f}_0\mathrm{}(980)\mathrm{}$ to be $\mathcal{O}{(10\mathrm{}}^{-4})$ $\left[\mathcal{O}{(10\mathrm{}}^{-5}\right)]$ while the unknown wave functions of $D^{\left(*\right)0\mathrm{}}$ $(J/\psi )$ are chosen to fit the observed decays of $\overline{B}\to D^{\left(*\right)0\mathrm{}}{\pi }^0$ $(J/\psi K^{0\left(*\right)}).\mathrm{}$

We analyze the matrix element of the electroweak current between $q\overline{q}$ vector meson states in the framework of a covariant extension of the light-front formalism. The light-front matrix element of a one-body current is naturally associated with zero modes, which affect some of the form factors that are necessary to represent the Lorentz structure of the light-front integral. The angular condition contains information on zero modes; i.e., only if the effect of zero modes is accounted for correctly is it satisfied. With plausible assumptions we derive from the angular condition several consistency conditions which can be used quite generally to determine the zero mode contribution of form factors. The correctness of this method is tested by the phenomenological success of the derived form factors. We compare the predictions of our formalism with those of the standard light-front approach and with available data. As examples we discuss the magnetic moment of the $\rho ,$ the coupling constant $g_{D^{*}D\pi },$ and the coupling constants of the pseudoscalar density, $g_{\pi }$ and $g_K,$ which provide a phenomenological link between constituent and current quark masses.

We study the semileptonic decay $\overrightarrow{B}\eta l\nu .$ The transition form factors for this decay are calculated by using light cone QCD sum rules. The branching ratio is estimated to be $B\left(\overrightarrow{B}\eta \nu \right)=(1.6\mathrm{}\pm 0.8)\times {10}^{-5}.$

We examine the total cross section of virtual photons on protons, ${\sigma }_{{\gamma }^{*}p}{(W}^2{,Q}^2),$ at low $x\cong Q^2{/W}^2\ll 1$ and its connection with “elastic” diffractive production ${\gamma }_{T,L}^{*}\overrightarrow{p}{X}_{T,L}^{J=1\mathrm{}}p$ in the two-gluon exchange dynamics for the virtual forward Compton scattering amplitude. Solely based on the generic structure of two-gluon exchange, we establish that the cross section is described by the (imaginary part of the) amplitude for forward scattering of $q\overline{q}$ vector states, $\left(q\overline{q}{)}_{T,L}^{J=1\mathrm{}}\overrightarrow{p}\right(q\overline{q}{)}_{T,L}^{J=1\mathrm{}}p.\mathrm{}$ The generalized vector dominance picture is accordingly established to only rest on the two-gluon-exchange generic structure. This is explicitly seen by the sum rules that allow one to directly relate the total cross section to the cross section for elastic diffractive forward production, ${\gamma }_{T,L}^{*}\overrightarrow{p}(q\overline{q}{)}_{T,L}^{J=1\mathrm{}}p,$ of vector states.

We present a study of the decays $B^0\to D_s^{\left(*\right)+}{D}^{*-},$ using $20.8\hspace{0.5em}{\mathrm{fb}}^{-1}$ of $e^{+}{e}^{-}$ annihilation data recorded with the BABAR detector. The analysis is conducted with a partial reconstruction technique, in which only the $D_s^{\left(*\right)+}$ and the soft pion from the $D^{*-}$ decay are reconstructed. We measure the branching fractions $\mathcal{B}{(B}^0\to D_s^{+}{D}^{*-})=(1.03\mathrm{}\pm 0.14\pm 0.13\pm 0.26)\%$ and $\mathcal{B}{(B}^0\to D_s^{*+}{D}^{*-})=(1.97\mathrm{}\pm 0.15\pm 0.30\pm 0.49)\%,$ where the first error is statistical, the second is systematic, and the third is the error due to the $D_s^{+}\to \phi {\pi }^{+}$ branching fraction uncertainty. From the $B^0\to D_s^{*+}{D}^{*-}$ angular distributions, we measure the fraction of longitudinal polarization ${\Gamma }_L/\Gamma =(51.9\mathrm{}\pm 5.0\pm 2.8)\%,$ which is consistent with theoretical predictions based on factorization.

We calculate the electroweak and finite width corrections to the decay of an unpolarized top quark into a bottom quark and a W-gauge boson where the helicities of the W are specified as longitudinal, transverse plus and transverse minus. Together with the $O\left({\alpha }_s\right)$ corrections these corrections may become relevant for the determination of the mass of the top quark through angular decay measurements.

Searching for a signal depending on unknown parameters in a noisy background with matched filtering techniques always requires an analysis of the data with several templates in parallel in order to ensure a proper match between the filter and the real waveform. The key feature of such an implementation is the design of the filter bank which must be small to limit the computational cost while keeping the detection efficiency as high as possible. This paper presents a geometrical method that allows one to cover the corresponding physical parameter space by a set of ellipses, each of them being associated with a given template. After the description of the main characteristics of the algorithm, the method is applied in the field of gravitational wave (GW) data analysis, for the search of damped sine signals. Such waveforms are expected to be produced during the deexcitation phase of black holes—the so-called “ringdown” signals—and are also encountered in some numerically computed supernova signals. First, the number of templates $\mathfrak{N}$ computed by the method is similar to its analytical estimation, despite the overlaps between neighbor templates and the border effects. Moreover, $\mathfrak{N}$ is small enough to test for the first time the performances of the set of templates for different choices of the minimal match $MM,$ the parameter used to define the maximal allowed loss of signal-to-noise ratio (SNR) due to the mismatch between real signals and templates. The main result of this analysis is that the fraction of SNR recovered is on average much higher than $MM,$ which dramatically decreases the mean percentage of false dismissals. Indeed, it goes well below its estimated value of $1-{\mathrm{MM}}^3$ used as input of the algorithm. Thus, as this feature should be common to any tiling algorithm, it seems possible to reduce the constraint on the value of $\mathrm{MM}$—and indeed the number of templates and the computing power—without losing as many events as expected on average. This should be of great interest for the inspiraling binaries case where the number of templates can reach some hundreds of thousands for the whole parameter space.

The lowest stationary quantum state of neutrons in the Earth’s gravitational field is identified in the measurement of neutron transmission between a horizontal mirror on the bottom and an absorber/scatterer on top. Such an assembly is not transparent for neutrons if the absorber height is smaller than the “height” of the lowest quantum state.

We show that by introducing appropriate local $Z_N(N>~13)$ symmetries in electroweak models it is possible to implement an automatic Peccei-Quinn symmetry, at the same time keeping the axion protected against gravitational effects. Although we consider here only an extension of the standard model and a particular 3-3-1 model, the strategy can be used in any kind of electroweak model. An interesting feature of this 3-3-1 model is that if we add (i) right-handed neutrinos, (ii) the conservation of the total lepton number, and (iii) a $Z_2$ symmetry, the $Z_{13}$ and the chiral Peccei-Quinn ${U\left(1\right)\mathrm{}}_{\mathrm{PQ}}$ symmetries are both accidental symmetries in the sense that they are not imposed on the Lagrangian but are just a consequence of the particle content of the model, its gauge invariance, renormalizability, and Lorentz invariance. In addition, this model has no domain wall problem.

We propose new production mechanisms for light fermiophobic Higgs bosons ${(h}_f)$ with suppressed couplings to vector bosons (V) at the Fermilab Tevatron. These mechanisms (e.g. ${\mathrm{qq}}^{\prime }\to H^{\pm }{h}_f)$ are complementary to the conventional process ${\mathrm{qq}}^{\prime }\to {\mathrm{Vh}}_f,$ which suffers from a strong suppression of $1/{\tan }^2\beta$ in realistic models with a $h_f.$ The new mechanisms extend the coverage at the Tevatron run II to the larger $\tan \beta$ region, and offer the possibility of observing new event topologies with up to four photons.

Cabibbo-allowed charmed meson decays into a pseudoscalar meson and an axial-vector meson are studied. The charm to axial-vector meson transition form factors are evaluated in the Isgur-Scora-Grinstein-Wise quark model. The dipole momentum dependence of the $\overrightarrow{D}K$ transition form factor and the presence of a sizable long-distance W exchange are the two key ingredients for understanding the data of $\overrightarrow{D}\overline{K}{a}_1.$ The $K_{1A}-K_{1B}$ mixing angle of the strange axial-vector mesons is found to be $\approx \pm 37°$ or $\pm 58°$ from $\overrightarrow{\tau }{K}_1{\nu }_{\tau }$ decays. The study of $\overrightarrow{D}{K}_1\mathrm{}\left(1270\right)\mathrm{}\pi ,$ $K_1\mathrm{}\left(1400\right)\mathrm{}\pi$ decays excludes the positive mixing-angle solutions. It is pointed out that an observation of the decay $D^0\to K_1^{-}\mathrm{}\left(1400\right)\mathrm{}{\pi }^{+}$ at the level of $5\times {10}^{-4}$ will rule out $\theta \approx -37°$ and favor the solution $\theta \approx -58°.$ Though the decays $D^0\to K_1^0{\pi }^0$ are color suppressed, they are comparable to and even larger than the color-allowed counterparts $K_1^0\mathrm{}\left(1270\right)\mathrm{}{\pi }^0\sim K_1^{-}\mathrm{}\left(1270\right)\mathrm{}{\pi }^{+}$ and $K_1^0\mathrm{}\left(1400\right)\mathrm{}{\pi }^0>K_1^{-}\mathrm{}\left(1400\right)\mathrm{}{\pi }^{+}.$ The finite width effect of the axial-vector resonance is examined. It becomes important for $a_1\mathrm{}\left(1260\right)\mathrm{}$ in particular when its width is near 600 MeV.

In this paper, we calculate the $\overrightarrow{B}\pi$ transition form factor $f_{B\pi }^{+}{(q}^2)$ by including perturbative $O\left({\alpha }_s\right)$ corrections to the twist-2 terms with chiral current in the light-cone QCD sum rule approach. The corrections to the product $f_B{f}_{B\pi }^{+}{(q}^2)$ in the leading twist approximation are found to be about $30\%,$ while a similar magnitude corresponding to $O\left({\alpha }_s\right)$ corrections for $f_B{(q}^2)$ in the two-point sum rule cancels them and results in small net corrections for $f_{B\pi }^{+}{(q}^2).\mathrm{}$ Our results confirm the observations made in previous light-cone QCD sum rule studies.

We construct operators that describe power corrections in mixed collinear-ultrasoft processes in QCD. We treat the ultrasoft-collinear Lagrangian to $\mathcal{O}\left({\lambda }^2\right)$ and heavy-to-light currents involving collinear quarks to $\mathcal{O}\left(\lambda \right),$ including new three body currents. A complete gauge invariant basis is derived which has a full reduction in Dirac structures and is valid for matching at any order in ${\alpha }_s.$ The full set of reparametrization invariance (RPI) constraints is included, and is found to restrict the number of parameters appearing in Wilson coefficients and to rule out some classes of operators. The QCD ultrasoft-collinear Lagrangian has two $\mathcal{O}\left({\lambda }^2\right)$ operators in its gauge invariant form. For the $\mathcal{O}\left(\lambda \right)$ heavy-to-light currents there are $\mathrm{}(4,4,14,14,21)\mathrm{}$ subleading (scalar, pseudoscalar, vector, axial-vector, tensor) currents, where $\mathrm{}(1,1,4,4,7)\mathrm{}$ have coefficients that are not determined by RPI. In a frame where $v_{\perp }=0\mathrm{}$ and $n\cdot v=1\mathrm{}$ the total number of currents reduces to $\mathrm{}(2,2,8,8,13),$ but the number of undetermined coefficients is the same. The role of these operators and universality of jet functions in the factorization theorem for heavy-to-light form factors is discussed.

Recent experimental determinations of the Nachtmann moments of the inelastic structure function of the proton, $F_2^p{(x,Q}^2),$ obtained at Jefferson Lab, are analyzed for values of the squared four-momentum transfer $Q^2$ ranging from $\approx 0.1$ to $\approx 2(\mathrm{GeV}{/c)}^2.$ It is shown that such inelastic proton data exhibit a new type of scaling behavior and that the resulting scaling function can be interpreted as a constituent form factor consistent with the elastic nucleon data. These findings suggest that at low momentum transfer the inclusive proton structure function originates mainly from the elastic coupling with extended objects inside the proton. We obtain a constituent size of $\approx 0.2–0.3\mathrm{fm}.$

A correlation and probability analysis of the distribution of arrival directions for a sample of AGASA events reported to have energies above $4\times {10}^{19}\mathrm{eV}$ shows the small scale clustering to remain significant at the 99.5–99.9% C.L. and to be consistent with previous results. For the sample taken as a whole, there are no departures from either homogeneity or isotropy on angular scales greater than $5°.$ The sample of events with $E>~6\times {10}^{19}\mathrm{eV}$ contains no pairs with separations $<4\mathrm{}°.$ Cross correlating subsamples partitioned by energy reveal three uncorrelated distributions in the intervals $(4\mathrm{}–5)\times {10}^{19}\mathrm{eV},$ $(5\mathrm{}–8)\times {10}^{19}\mathrm{eV},$ and greater than $8\times {10}^{19}\mathrm{eV}.$ The partition with $5<~E<\mathrm{}8\mathrm{}\times {10}^{19}\mathrm{eV}$ is correlated with the supergalactic equatorial plane while the other two groups are statistically consistent with isotropic distributions. The presence of three distinct energy-partitioned groups of events could reflect possible changes in primary composition, different source distributions, differing levels of GZK losses, or deflection effects of magnetic fields.

We measured the inclusive electron-proton cross section in the nucleon resonance region $(W<\mathrm{}2.5\mathrm{}\mathrm{GeV})$ at momentum transfers $Q^2$ below $4.5(\mathrm{GeV}{/c)}^2$ with the CLAS detector. The large acceptance of CLAS allowed the measurement of the cross section in a large, contiguous two-dimensional range of $Q^2$ and x, making it possible to perform an integration of the data at fixed $Q^2$ over the significant x interval. From these data we extracted the structure function $F_2$ and, by including other world data, we studied the $Q^2$ evolution of its moments, $M_n{(Q}^2),$ in order to estimate higher twist contributions. The small statistical and systematic uncertainties of the CLAS data allow a precise extraction of the higher twists and will require significant improvements in theoretical predictions if a meaningful comparison with these new experimental results is to be made.

We show that noncommuting electric fields occur naturally in $\theta$-expanded noncommutative gauge theories. Using this noncommutativity, which is field dependent, and a Hamiltonian generalization of the Seiberg-Witten map, the algebraic consistency in the Lagrangian and Hamiltonian formulations of these theories is established. A comparison of results in different descriptions shows that this generalized map acts as a canonical transformation in the physical subspace only. Finally, we apply the Hamiltonian formulation to derive the gauge symmetries of the action.