1,249 research outputs found
L1599B: Cloud Envelope and C+ Emission in a Region of Moderately Enhanced Radiation Field
We study the effects of an asymmetric radiation field on the properties of a
molecular cloud envelope. We employ observations of carbon monoxide (12CO and
13CO), atomic carbon, ionized carbon, and atomic hydrogen to analyze the
chemical and physical properties of the core and envelope of L1599B, a
molecular cloud forming a portion of the ring at approximately 27 pc from the
star Lambda Ori. The O III star provides an asymmetric radiation field that
produces a moderate enhancement of the external radiation field. Observations
of the [CII] fine structure line with the GREAT instrument on SOFIA indicate a
significant enhanced emission on the side of the cloud facing the star, while
the [Ci], 12CO and 13CO J = 1-0 and 2-1, and 12CO J = 3-2 data from the PMO and
APEX telescopes suggest a relatively typical cloud interior. The atomic, ionic,
and molecular line centroid velocities track each other very closely, and
indicate that the cloud may be undergoing differential radial motion. The HI
data from the Arecibo GALFA survey and the SOFIA/GREAT [CII] data do not
suggest any systematic motion of the halo gas, relative to the dense central
portion of the cloud traced by 12CO and 13CO.Comment: 9 Figure
Crescimento e incremento de Sequoia sempervirens (D. Don) Endl., São Joaquim, SC.
O presente trabalho teve como objetivo estudar a forma de crescimento e calcular o incremento médio e corrente anual das variáveis dendrométricas de Sequoia sempervirens, de mudas originárias dos EUA e cultivadas no campo experimental da EPAGRI em São Joaquim, SC. Para isso, ajustou-se e selecionou-se um entre modelos lineares e não lineares que se mostraram eficientes, permitindo identificar as formas do crescimento de acordo com a idade. Os resultados obtidos demonstram que aos 18 anos o incremento médio anual em altura foi de 0,55 m/árvore/ano e o incremento médio em volume foi de 0,76 m3/árvore/ano, indicando um ótimo potencial de crescimento. Para volume e diâmetro a equação selecionada foi de Schumacker com R2aj. de 0,9558 e Syx de 0,7 cm para diâmetro, e para volume R2aj. de 0,9421 e Syx de 0,8694 m3, para a variável altura o modelo selecionado foi de Chapman-Richards com R2aj. de 0,98 e Syx de 0,5364 m. Os resultados demonstraram que a espécie teve um incremento médio em diâmetro de 2,5 cm na região, semelhante aos plantios comerciais de pinus, com ponto de rotação técnica em volume aos 70 anos, podendo ser cultivada comercialmente
Quark-antiquark composite systems: the Bethe-Salpeter equation in the spectral-integration technique
The Bethe-Salpeter equations for the light-quark composite systems, q q-bar,
are written in terms of spectral integrals. For the q q-bar -mesons
characterized by the mass M, spin J and radial quantum number n, the equations
are presented for the following (n,M^2)-trajectories: pi_J, eta_J, a_J, f_J,
rho_J, omega_J, h_J and b_J.Comment: 42 pages, 5 figures, typos correcte
Splitting of the pi - rho spectrum in a renormalized light-cone QCD-inspired model
We show that the splitting between the light pseudo-scalar and vector meson
states is due to the strong short-range attraction in the ^1S_0 sector which
makes the pion and the kaon light particles. We use a light-cone QCD-inspired
model of the mass squared operator with harmonic confinement and a Dirac-delta
interaction. We apply a renormalization method to define the model, in which
the pseudo-scalar ground state mass fixes the renormalized strength of the
Dirac-delta interaction.Comment: 9 pages, 2 figures, revtex, accepted by Phys. Rev. D; Corrected typo
Baryon spectra with instanton induced forces
Except the vibrational excitations of and mesons, the main features
of spectra of mesons composed of quarks , , and can be quite well
described by a semirelativistic potential model including instanton induced
forces. The spectra of baryons composed of the same quarks is studied using the
same model. The results and the limitations of this approach are described.
Some possible improvements are suggested.Comment: 5 figure
Measurement of ultrashort bi-photon correlation times with an integrated two-colour broadband SU(1,1)-interferometer
The bi-photon correlation time, a measure for the conditional uncertainty in
the temporal arrival of two photons from a photon pair source, is a key
performance identifier for many quantum spectroscopy applications, with shorter
correlation times typically yielding better performance. Furthermore, it
provides fundamental insight into the effects of dispersion on the bi-photon
state. Here, we retrieve ultrashort bi-photon correlation times of around
by measuring simultaneously spectral and temporal
interferograms at the output of an SU(1,1) interferometer based on an
integrated broadband parametric down-conversion source in a
waveguideComment: 8 pages, 5 figure
Highly multimode memory in a crystal
We experimentally demonstrate the storage of 1060 temporal modes onto a
thulium-doped crystal using an atomic frequency comb (AFC). The comb covers
0.93 GHz defining the storage bandwidth. As compared to previous AFC
preparation methods (pulse sequences i.e. amplitude modulation), we only use
frequency modulation to produce the desired optical pumping spectrum. To ensure
an accurate spectrally selective optical pumping, the frequency modulated laser
is self-locked on the atomic comb. Our approach is general and should be
applicable to a wide range of rare-earth doped material in the context of
multimode quantum memory
FMNH2-dependent monooxygenases initiate catabolism of sulfonamides in Microbacterium sp. strain BR1 subsisting on sulfonamide antibiotics
Quark--antiquark states and their radiative transitions in terms of the spectral integral equation. {\Huge III.} Light mesons
We continue the investigation of mesons in terms of the spectral integral
equation initiated before [hep-ph/0510410, hep-ph/0511005] for the
and systems: in this paper we consider the light-quark ()
mesons with masses GeV. The calculations have been performed for the
mesons lying on linear trajectories in the -planes, where is the
radial quantum number. Our consideration relates to the states with
one component in the flavor space, with the quark and antiquark masses equal to
each other, such as , , ,
, , , , ,
, , , ,
, at . We obtained the wave functions
and mass values of mesons lying on these trajectories. The corresponding
trajectories are linear, in agreement with data. We have calculated the
two-photon decays , ,
, , and radiative transitions ,
, that agree qualitatively with the experiment. On this
basis, we extract the singular part of the interaction amplitude, which
corresponds to the so-called "confinement interaction". The description of the
data requires the presence of the strong -channel singularities for both
scalar and vector exchanges.Comment: 48 pages, 24 figure
Quark--antiquark states and their radiative transitions in terms of the spectral integral equation. {\Huge II.} Charmonia
In the precedent paper of the authors (hep-ph/0510410), the states
were treated in the framework of the spectral integral equation, together with
simultaneous calculations of radiative decays of the considered bottomonia. In
the present paper, such a study is carried out for the charmonium
states. We reconstruct the interaction in the -sector on the basis of
data for the charmonium levels with , , ,
, , and radiative transitions
, , ,
and , ,
. The levels and their wave functions
are calculated for the radial excitations with . Also, we determine the
component of the photon wave function using the annihilation
data: , , , , , and perform the calculations of the partial widths of
the two-photon decays for the states: , ,
, and states:
, , . We discuss the status of the recently observed states
X(3872) and Y(3941): according to our results, the X(3872) can be either
or , while Y(3941) is .Comment: 24 pages, 9 figure
- …