Brans-Dicke Wormhole Revisited

A basic constraint to be satisfied by Brans class I solution for being a traversible wormhole is derived. It is argued that the solution could be a wormhole analogue of the Horowitz-Ross naked black hole. It is further demonstrated that the wormhole is traversible only "in principle", but not in practice. Using a recently proposed measure of total gravitational energy inside a static wormhole configuration, it is shown that the wormhole contains repulsive gravity required for the defocussing of orbits at the throat.Comment: 13 pages, 6 figures, accepted for publication in Class. Quant. Gra

Non-factorizable long distance contributions in color suppressed decays of B mesons

$\bar B \to D\pi$, $D^*\pi$, $J/\psi\bar K$ and $J/\psi\pi$ decays are studied. Their amplitude is given by a sum of factorized and non-factorizable ones. The latter which is estimated by using a hard pion approximation is rather small in color favored $\bar B \to D\pi$ and $D^*\pi$ decays but still can efficiently interfere with the main amplitude given by the factorization. In the color suppressed $\bar B \to J/\psi\bar K$ and $J/\psi\pi$ decays, the non-factorizable contribution is very important. The sum of the factorized and non-factorizable amplitudes can reproduce well the existing experimental data on the branching ratios for the color favored $\bar B \to D\pi$ and $D^*\pi$ and the color suppressed $\bar B \to J/\psi \bar K$ and $J/\psi\pi$ decays by taking reasonable values of unknown parameters involved.Comment: 19 pages, Revte

Performance of combined tillage equipment and it’s effect on soil properties

An experiment was conducted to evaluate the performance of a locally manufactured combined tillage implement (moldboard plow + ripper) in one of the fields of the kufa university faculty of agriculture. The experiment was included two factors , the first factor is combing the ripper to mold board plow in five level these are fixing the combined ripper shanks while the shanks points oriented in two different levels with and opposite to the plowing direction , two levels of different ripper depths the same depth and 5 cm above the depth of mold board plow share and the fifth level is control treatment ( mold board plow alone ) .The second factor was the plowing operation speed at five levels (1.4, 2.0 , 3.6 and 4.7) Km.hr ̵ ¹ . the experiment was conducted as a factorial experiment with RCBD , the LSD test at 5 % was used to compare between means .The results of the research were showed that combining the locally manufactured ripper implement to mold board plow resulted in significant increase in the number of soil clods with the desired diameter (5-10 cm ) very low number of soil block with diameter larger than 10 cm , more even soil roughness and the actual productivity has not decreased to the extent that it affects the efficient performance of the tillage process compared to the use at the mold board plow alone

A Nonsingular Brans Wormhole: An Analogue to Naked Black Holes

In a recent paper, we showed the Jordan frame vacuum Brans Class I solution provided a wormhole analogue to Horowitz-Ross naked black hole in the wormhole range -3/2<{\omega}<-4/3. Thereafter, the solution has been criticized by some authors that, because of the presence of singularity in that solution within this range, a wormhole interpretation of it is untenable. While the criticism is correct, we show here that (i) a singularity-free wormhole can actually be obtained from Class I solution by performing a kind of Wick rotation on it, resulting into what Brans listed as his independent Class II solution (ii) the Class II solution has all the necessary properties of a regular wormhole in a revised range -2<{\omega}<-3/2 and finally, (iii) naked black holes, as described by Horowitz and Ross, are spacetimes where the tidal forces attain their maxima above the black hole horizon. We show that in the non-singular Class II spacetime this maxima is attained above the throat and thus can be treated as a wormhole analogue. Some related issues are also addressed.Comment: 20 pages, 4 figure

Resonant Two-body D Decays

The contribution of a $K^*(1430)$ $0^+$ resonance to $D^0\to K^-\pi^+$ is calculated by applying the soft pion theorem to $D^+ \to K^* \pi^+$, and is found to be about 30% of the measured amplitude and to be larger than the $\Delta I=3/2$ component of this amplitude. We estimate a 70% contribution to the total amplitude from a higher $K^*(1950)$ resonance. This implies large deviations from factorization in D decay amplitudes, a lifetime difference between D^0 and D^+, and an enhancement of $D^0-\bar D^0$ mixing due to SU(3) breaking.Comment: To be published in Physical Review Letters, some corrections, references update

Bound States of String Networks and D-branes

We show the existence of non-threshold bound states of (p, q) string networks and D3-branes, preserving 1/4 of the full type IIB supersymmetry, interpreted as string networks dissolved in D3-branes. We also write down the expression for the mass density of the system and discuss the extension of the construction to other Dp-branes. Differences in our construction of string networks with the ones interpreted as dyons in N=4 gauge theories are also pointed out.Comment: 11 pages, latex, minor modifications (version to appear in Phys. Rev. Lett.

Weak radiative hyperon decays, Hara's theorem and the diquark

Weak radiative hyperon decays are discussed in the diquark-level approach. It is pointed out that in the general diquark formalism one may reproduce the experimentally suggested pattern of asymmetries, while maintaining Hara's theorem in the SU(3) limit. At present, however, no detailed quark-based model of parity-violating diquark-photon coupling exists that would have the necessary properties.Comment: 10 pages, LaTe

Quantum dynamics of local phase differences between reservoirs of driven interacting bosons separated by simple aperture arrays

We present a derivation of the effective action for the relative phase of driven, aperture-coupled reservoirs of weakly-interacting condensed bosons from a (3+1)-D microscopic model with local U(1) gauge symmetry. We show that inclusion of local chemical potential and driving velocity fields as a gauge field allows derivation of the hydrodynamic equations of motion for the driven macroscopic phase differences across simple aperture arrays. For a single aperture, the current-phase equation for driven flow contains sinusoidal, linear, and current-bias contributions. We compute the renormalization group (RG) beta function of the periodic potential in the effective action for small tunneling amplitudes and use this to analyze the temperature dependence of the low-energy current-phase relation, with application to the transition from linear to sinusoidal current-phase behavior observed in experiments by Hoskinson et al. \cite{packard} for liquid $^{4}$He driven through nanoaperture arrays. Extension of the microscopic theory to a two-aperture array shows that interference between the microscopic tunneling contributions for individual apertures leads to an effective coupling between apertures which amplifies the Josephson oscillations in the array. The resulting multi-aperture current-phase equations are found to be equivalent to a set of equations for coupled pendula, with microscopically derived couplings.Comment: 16 pages, 5 figures v2: typos corrected, RG phase diagram correcte

CeCoIn5 - a quantum critical superfluid

We have made the first complete measurements of the London penetration depth $\lambda(T)$ of CeCoIn5, a quantum-critical metal where superconductivity arises from a non-Fermi-liquid normal state. Using a novel tunnel diode oscillator designed to avoid spurious contributions to $\lambda(T)$, we have established the existence of intrinsic and anomalous power-law behaviour at low temperature. A systematic analysis raises the possibility that the unusual observations are due to an extension of quantum criticality into the superconducting state.Comment: 5 pages, 3 figure