4,700 research outputs found

    Status of ψ\psi (3686), ψ\psi (4040), ψ\psi (4160), Y (4260), ψ\psi (4415) and X (4630) charmonia like states

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    We examine the status of charmonia like states by looking into the behaviour of the energy level differences and regularity in the behaviour of the leptonic decay widths of the excited charmonia states. The spectroscopic states are studied using a phenomenological Martin-like confinement potential and their radial wave functions are employed to compute the di-leptonic decay widths. Their deviations from the expected behaviour provide a clue to consider them as admixtures of the nearby S and D states. The present analysis strongly favour \\backslash$psi \$ (3686) as admixture of $c \bar{c}$ (2S) and $c \bar{c}$g (4.1 GeV) hybrid, \\backslashpsi$(4040)and$psi \$ (4040) and \$\backslashpsi$(4160)asadmixturestatesofcharmonia(3S,3D)stateswithmixingangle$psi \$ (4160) as admixture states of charmonia (3S, 3D) states with mixing angle \$\backslashtheta$=11theta \$ = 11^\circand45 and 45^\circrespectively.WeidentifyY(4260)asapure respectively. We identify Y (4260) as a pure c \bar{c}(4S)statewhoseleptonicdecayispredictedas0.65keV.WhileX(4630)isclosertothe (4S) state whose leptonic decay is predicted as 0.65 keV. While X(4630) is closer to the c \bar{c}(6S)state.Thestatusof$ (6S) state. The status of \$\backslash$psi \$ (4415) is still not clear as it does not fit to be pure or admixture state

    Characterization of Hydride-Based Silica and Diamond Hydride Stationary Phases

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    Aqueous normal phase chromatography possesses characteristics of both normal phase (NP) and also reverse phase (RP) chromatography. It can retain polar as well as non-polar compounds by carefully selecting the concentration ratio of organic solvent to water in the mobile phase. Silica hydride columns contain only a small percentage of silanol groups which are polar in nature and have an effect on the separation process. Diamond hydride columns consist of a small amount (~2%) of carbon chemically bonded to a silica hydride surface. This research work characterized both hydride-based silica and diamond hydride stationary phases under isocratic and gradient conditions. Both columns were compared using the same conditions, and their efficiencies and symmetries were calculated. Diamond hydride showed different selectivity than the silica hydride column because of the 2% carbon on the silica hydride surface. This research work shows that both the silica hydride and diamond hydride columns can be used in aqueous normal phase conditions

    Young stars and dust in AFGL437: NICMOS/HST polarimetric imaging of an outflow source

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    We present near infrared broad band and polarimetric images of the compact star forming cluster AFGL437 obtained with the NICMOS instrument aboard HST. Our high resolution images reveal a well collimated bipolar reflection nebulosity in the cluster and allow us to identify WK34 as the illuminating source. The scattered light in the bipolar nebulosity centered on this source is very highly polarized (up to 79%). Such high levels of polarization implies a distribution of dust grains lacking large grains, contrary to the usual dust models of dark clouds. We discuss the geometry of the dust distribution giving rise to the bipolar reflection nebulosity and make mass estimates for the underlying scattering material. We find that the most likely inclination of the bipolar nebulosity, south lobe inclined towards Earth, is consistent with the inclination of the large scale CO molecular outflow associated with the cluster, strengthening the identification of WK34 as the source powering it.Comment: 26 pages, 10 figues. Accepted for publication in the Astrophysical Journa

    High magnetic field pulsars and magnetars: a unified picture

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    We propose a unified picture of high magnetic field radio pulsars and magnetars by arguing that they are all rotating high-field neutron stars, but have different orientations of their magnetic axes with respective to their rotation axes. In strong magnetic fields where photon splitting suppresses pair creation near the surface, the high-field pulsars can have active inner accelerators while the anomalous X-ray pulsars cannot. This can account for the very different observed emission characteristics of the anomalous X-ray pulsar 1E 2259+586 and the high field radio pulsar PSR J1814-1744. A predicted consequence of this picture is that radio pulsars having surface magnetic field greater than about 2×10142\times 10^{14} G should not exist.Comment: 5 pages, emulateapj style, accepted for publication in the ApJ Letter
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