12,970 research outputs found
Constraints on the Formation of the Planet Around HD188753A
The claimed discovery of a Jupiter-mass planet in the close triple star
system HD 188753 poses a problem for planet formation theory. A circumstellar
disk around the planet's parent star would be truncated close to the star,
leaving little material available for planet formation. In this paper, we
attempt to model a protoplanetary disk around HD 188753A using a fairly simple
alpha-disk model, exploring a range of parameters constrained by observations
of T Tauri-type stars. The disk is truncated to within 1.5 to 2.7 AU, depending
on model parameters. We find that the in situ formation of the planet around HD
188753A is implausible.Comment: Accepted version, to appear in ApJ. 23 pages, 5 figures (3 in color
Isometric Representations of Totally Ordered Semigroups
Let S be a subsemigroup of an abelian torsion-free group G. If S is a
positive cone of G, then all C*-algebras generated by faithful isometrical
non-unitary representations of S are canonically isomorphic. Proved by Murphy,
this statement generalized the well-known theorems of Coburn and Douglas. In
this note we prove the reverse. If all C*-algebras generated by faithful
isometrical non-unitary representations of S are canonically isomorphic, then S
is a positive cone of G. Also we consider G = Z\times Z and prove that if S
induces total order on G, then there exist at least two unitarily not
equivalent irreducible isometrical representation of S. And if the order is
lexicographical-product order, then all such representations are unitarily
equivalent.Comment: February 21, 2012. Kazan, Russi
Nonlinear refractive index and three-photon absorption coefficient of poly(9,9-dioctylfluorence)
We investigate the optical Kerr effect and third harmonic generation (THG) arising from chi((3)) of poly(9,9-dioctylfluorence), which is an emerging organic pi-conjugated polymer from the perspective of diverse optoelectronic applications. The measured nonlinear refractive index, obtained with closed-aperture Z-scan, is n(2)=(2.04 +/- 0.10)x10(-12) esu at lambda=1540 nm. Open-aperture Z-scan yields the three-photon absorption coefficient of gamma=(1.88 +/- 0.26)x10(-3) cm(3)/GW(2) at lambda=1064 nm, arising from chi((5)) response. The wavelength-dependent THG indicates that this semiconducting polymer can be a potentially useful polymer system for nonlinear-optics applications involving high-order optical processes in the mid-IR range. (C) 2009 American Institute of Physics. (doi:10.1063/1.3269588
Production and optical properties of liquid scintillator for the JSNS experiment
The JSNS (J-PARC Sterile Neutrino Search at J-PARC Spallation Neutron
Source) experiment will search for neutrino oscillations over a 24 m short
baseline at J-PARC. The JSNS inner detector will be filled with 17 tons
of gadolinium-loaded liquid scintillator (LS) with an additional 31 tons of
unloaded LS in the intermediate -catcher and outer veto volumes.
JSNS has chosen Linear Alkyl Benzene (LAB) as an organic solvent because
of its chemical properties. The unloaded LS was produced at a refurbished
facility, originally used for scintillator production by the RENO experiment.
JSNS plans to use ISO tanks for the storage and transportation of the LS.
In this paper, we describe the LS production, and present measurements of its
optical properties and long term stability. Our measurements show that storing
the LS in ISO tanks does not result in degradation of its optical properties.Comment: 7 pages, 4 figures
B -> Xs l_i^+ l_j^+ Decays with R-parity Violation
We derive the upper bounds on certain products of R-parity- and
lepton-flavor-violating couplings from B \ra X_s {l_i}^+ {l_j}^- decays.
These modes of B-meson decays can constrain the product combinations of the
couplings with one or more heavy generation indices which are comparable with
or stronger than the present bounds. From the studies of the invariant dilepton
mass spectrum and the forward backward asymmetry of the emitted leptons we note
the possibility of detecting R-parity-violating signals even when the total
decay rate due to R-parity violating couplings is comparable with that in the
standard model and discriminating two types of R-parity-violating signals. The
general expectation of the enhancement of the forward backward asymmetry of the
emitted leptons in the minimal supersymmetric standard model with R-parity may
be corrupted by R-parity violation.Comment: 10 pages, Revtex, 1 table and 2 figure
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