1,003 research outputs found
Observation of the Y(1(3)D(J)) bottomonium state through decays to pi(+)pi Y-(1S)
No full textBased on 122 X 10(6)Y(3S) events collected with the BABAR detector, we have observed the Y(1(3)D(J)) bottomonium state through the Y(3S) -> gamma gamma Y(1(3)D(J)) -> gamma gamma pi(+)pi Y-(1S) decay chain. The significance for the J = 2 member of the Y(1(3)D(J)) triplet is 5.8 standard deviations including systematic uncertainties. The mass of the J = 2 state is determined to be 10 164.5 +/- 0.8(stat) +/- 0.5(syst) MeV/c(2). We use the pi(+)pi(-) invariant mass distribution to confirm the consistency of the observed state with the orbital angular momentum assignment of the Y(1(3)D(J))
Magnetic metasurfaces properties in the near field regions
No full textIn this paper, we present a general equivalent-circuit interpretation of finite magnetic metasurfaces interacting with an arbitrary arrangement of RF coils operating in near-field regime. The developed model allows to derive a physical interpretation of the interactions between the metasurface and the surrounding RF coils, both transmitting and receiving. Indeed, especially for near-field applications, the metasurface presence modifies the behavior of each RF coil differently, due to the specific reciprocal interactions. Hence, the proposed approach introduces a source-related complex magnetic permeability matrix, overcoming the traditional bulk definition. To prove the model validity against full-wave simulations, we present two significant test cases, commonly used in practical applications. The former is represented by the simple metasurface-coil arrangement from which important and fundamental considerations can be drawn. The latter system is composed by a transmitting and a receiving coil with a metasurface in between; detailed explanations on the metasurface interactions with both the RF coils are developed. Finally, we also achieved an excellent agreement between the numerical results and the measurements obtained through fabricated prototypes. In summary, the circuit interpretation herein presented, in addition to the rigorous electromagnetic theoretical approaches already appeared in the open literature, reveals useful in providing quantitative, practical, and easy-to-handle guidelines for the design and physical understanding of finite magnetic metasurfaces interacting with arbitrary RF coils arrangements in the near-field regime
An analytical approach for the arbitrary control of magnetic metasurfaces frequency response
No full textIn this letter, we develop an accurate and effective analytical framework to arbitrarily manipulate the frequency response of magnetic metasurfaces. In particular, we demonstrate the possibility to homogenize the response of the unit cells constituting a finite slab, avoiding undesired truncation effects and, consequently, performance degradation. In addition, we also show that the control over the current flowing in each array element can be arbitrary, thus allowing exotic properties accomplishment. For instance, we prove that the magnetic field distribution reconfigurability can be easily achieved. We finally demonstrate the reliability of the procedure based on the theoretical circuit model through full-wave simulations performed over meaningful test cases. The possibility to accurately control the response of magnetic metasurfaces can be extremely important for enhancing performance in numerous applications, as for instance wireless power transfer and magnetic resonance imaging
On the Arbitrary Control of Passive Magnetic Metasurfaces Response
No full textIn this paper, an analytic circuital approach to manipulate the response of magnetic metasurfaces is introduced. In particular, we show that the control over the current flowing in each array element can be arbitrary, thus allowing exotic properties accomplishment. For instance, we prove that beam-steering capability can be easily achieved. The reliability of the proposed analytical model is proved performing full-wave simulations over a test-case configuration. The accurate control on the overall metasurface response can be extremely significant in a number of applications, such as resonant inductive Wireless Power Transfer, reconfigurable antennas and Magnetic Resonance Imaging
Exclusive Initial-State-Radiation Production of the D-bar D, D-bar D*, and D*-bar D* Systems
No full textErratum: Exclusive initial-state-radiation production of the DD̄, D*D̄, and D*D̄* systems (Physical Review D - Particles, Fields, Gravitation and Cosmology (2009) 79 (092001))
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Measurement of the Semileptonic Decays B --> D tau- nubar_tau and B --> D* tau- nubar_tau
No full textA Highly Selective Rasorber With Ultraminiaturized Unit Based on Interdigitated 2.5-D Parallel Resonator
No full textA high selectivity frequency selective rasorber (FSR) with an ultraminiaturized unit based on 2.5 dimensional (2.5-D) parallel resonator (PR), exhibiting low insertion loss passband between two absorption bands, is investigated. The lossy unit is realized by inserting a 2.5-D strip-type PR structure into the center of each side of the metal square ring and loaded with resistors connected at the four corners. The novel 2.5-D PR consists of interdigitated capacitors and strip metal wire connecting the other side of the lossy layer obtained by using metallized vias. The 2.5-D PR can effectively alleviate the congestion of the single-sided structures and achieve a high degree of miniaturization by means of tortuous extension inductance structure; as an additional feature, the values of L and C can be independently adjusted to determine the passband frequency allowing to provide additional degree of freedom to the design. An equivalent circuit model is proposed to analyze its operating principle. The dimensions of the miniaturized unit are (being the free space wavelength at the passband). A transmission window with low insertion loss of 0.125 dB is obtained at 4.65 GHz under normal incidence. The fractional bandwidth for -10 dB reflection is about 96%. The miniaturized FSR satisfies the characteristic of polarization insensitivity (TE and TM) and angular insensitivity (up to 45 degrees). A prototype of miniaturized FSR has been manufactured and measured, showing a reasonable agreement with simulations
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