4,605 research outputs found
Geodesic properties in terms of multipole moments in scalar-tensor theories of gravity
The formalism for describing a metric and the corresponding scalar in terms
of multipole moments has recently been developed for scalar-tensor theories. We
take advantage of this formalism in order to obtain expressions for the
observables that characterise geodesics in terms of the moments. These
expressions provide some insight into how the structure of a scalarized compact
object affects observables. They can also be used to understand how deviations
from general relativity are imprinted on the observables.Comment: 16 page
Dynamic load management and optimum sizing of stand-alone hybrid PV/Wind system.
Simulation algorithms for the sizing of stand-alone hybrid PV/Wind systems are a powerful tool in evaluating the optimum configuration that would cover the energy demand with a predefined reliability level at the lowest cost. Several parameters such as the interval of the simulation (day, day-night, hourly) and the consumption profile may significantly affect the optimum configuration. This paper examines the effect of these parameters within an optimum sizing simulation algorithm developed. The effect of these parameters was particularly evident at low battery capacities, which involve optimum configurations resulting in minimum cost. Furthermore, shift-able loads in the hourly-based weekly profile assumed in this study were identified, and a dynamic load management functionality was developed. In this approach, loads that could be shifted through time were dynamically allocated during periods of excess energy production by the hybrid PV/Wind system. The results showed an increase in system reliability from 95% to 97% when load shifting was introduced. Finally, sizing the system for only the static (non-shift-able loads) proved to withstand the addition of the extra shift-able loads while retaining the 95% reliability level when the load management functionality was introduced. Thus, a smaller installation with lower cost is achieved
Matching of analytical and numerical solutions for neutron stars of arbitrary rotation
We demonstrate the results of an attempt to match the two-soliton analytical
solution with the numerically produced solutions of the Einstein field
equations, that describe the spacetime exterior of rotating neutron stars, for
arbitrary rotation. The matching procedure is performed by equating the first
four multipole moments of the analytical solution to the multipole moments of
the numerical one. We then argue that in order to check the effectiveness of
the matching of the analytical with the numerical solution we should compare
the metric components, the radius of the innermost stable circular orbit
(), the rotation frequency and the
epicyclic frequencies . Finally we present some
results of the comparison.Comment: Contribution at the 13th Conference on Recent Developments in Gravity
(NEB XIII), corrected typo in of eq. 5 of the published versio
Observation of B_s Production at the Y(5S) Resonance
Using the CLEO detector at the Cornell Electron Storage Ring, we have observed the B_s meson in e^+e^- annihilation at the Υ(5S) resonance. We find 14 candidates consistent with B_s decays into final states with a J/ψ or a D_s^((*)-). The probability that we have observed a background fluctuation is less than 8×10^(-10). We have established that at the energy of the Υ(5S) resonance B_s production proceeds predominantly through the creation of B_s^*B̅ _s^* pairs. We find σ(e^+e^-→B^s^*B̅ ^*)=[0.11_(-0.03)^(+0.04)(stat)±0.02(syst)] nb, and set the following limits: σ(e^+e^-→B_sB̅ _s)/σ(e^+e^-→B_s^*B̅ _s^*)<0.16 and [σ(e^+e^-→B_sB̅ _s^*)+σ(e^+e^-→B_s*B̅ _s)]/σ(e^+e^-→B_s*B̅ _s^*)<0.16 (90% C.L.). The mass of the B_s^* meson is measured to be M_(B_s^*=[5.414±0.001(stat)±0.003(syst)] GeV/c^2
Two-photon width of the charmonium state X_(c2)
The two-photon width of X_(c2)^3P_2 state of charmonium has been measured using 14.4 fb^(-1) of e^+e^-data taken at √s
=9.46–11.30 GeV with the CLEO III detector. The yy-fusion reaction studied is e^+e^- → e^+e^-yy, → yy X_(c2) → yJ/Ψ → ye^+e^-(µ^+µ^-). We measure Г_(yy) (X_(c2))B(X_(c2)) → y
J/Ψ)B(J/Ψ → e^+e^- + µ^+µ^-)= 13.2 ± 1.4(stat)± 1.1(syst) eV, and obtain Г yy(Xc2)= 559 ± 57(stat) ± 48(syst) ± 36(br) eV. This result is in excellent agreement with the result of -fusion measurement by Belle and is consistent with that of the pp → X_(c2) → yy measurement, when they are both reevaluated using the recent CLEO result for the radiative decay X_(c2) → J/Ψ
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