5,059 research outputs found
Status of (3686), (4040), (4160), Y (4260), (4415) and X (4630) charmonia like states
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, \\backslash\backslash\backslash^\circ^\circc \bar{c}c \bar{c}\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
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
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
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 G should not exist.Comment: 5 pages, emulateapj style, accepted for publication in the ApJ
Letter
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