1,525 research outputs found
Nuclear dependence of azimuthal asymmetry in semi-inclusive deep inelastic scattering
Within the framework of a generalized factorization, semi-inclusive deeply
inelastic scattering (SIDIS) cross sections can be expressed as a series of
products of collinear hard parts and transverse-momentum-dependent (TMD) parton
distributions and correlations. The azimuthal asymmetry $ is studied. It is shown that the azimuthal
asymmetry is suppressed by multiple parton scattering and the transverse
momentum dependence of the suppression depends on the relative shape of the
twist-2 and 3 quark distributions in the nucleon. A Gaussian ansatz for TMD
twist-2 and 3 quark distributions in nucleon is used to demonstrate the nuclear
dependence of the azimuthal asymmetry and to estimate the smearing effect due
to fragmentation.Comment: 9 pages in RevTex with 2 figure
Filament L1482 in the California molecular cloud
Aims. The process of gravitational fragmentation in the L1482 molecular
filament of the California molecular cloud is studied by combining several
complementary observations and physical estimates. We investigate the kinematic
and dynamical states of this molecular filament and physical properties of
several dozens of dense molecular clumps embedded therein.
Methods. We present and compare molecular line emission observations of the
J=2--1 and J=3--2 transitions of 12CO in this molecular complex, using the
KOSMA 3-meter telescope. These observations are complemented with archival data
observations and analyses of the 13CO J=1--0 emission obtained at the Purple
Mountain Observatory 13.7-meter radio telescope at Delingha Station in QingHai
Province of west China, as well as infrared emission maps from the Herschel
Space Telescope online archive, obtained with the SPIRE and PACS cameras.
Comparison of these complementary datasets allow for a comprehensive
multi-wavelength analysis of the L1482 molecular filament.
Results. We have identified 23 clumps along the molecular filament L1482 in
the California molecular cloud. All these molecular clumps show supersonic
non-thermal gas motions. While surprisingly similar in mass and size to the
much better known Orion molecular cloud, the formation rate of high-mass stars
appears to be suppressed in the California molecular cloud relative to that in
the Orion molecular cloud based on the mass-radius threshold derived from the
static Bonnor Ebert sphere. Our analysis suggests that these molecular
filaments are thermally supercritical and molecular clumps may form by
gravitational fragmentation along the filament. Instead of being static, these
molecular clumps are most likely in processes of dynamic evolution.Comment: 10 pages, 9 figures, 2 tables, accepted to Astronomy and Astrophysic
Remote information concentration and multipartite entanglement in multilevel systems
Remote information concentration (RIC) in -level systems (qudits) is
studied. It is shown that the quantum information initially distributed in
three spatially separated qudits can be remotely and deterministically
concentrated to a single qudit via an entangled channel without performing any
global operations. The entangled channel can be different types of genuine
multipartite pure entangled states which are inequivalent under local
operations and classical communication. The entangled channel can also be a
mixed entangled state, even a bound entangled state which has a similar form to
the Smolin state, but has different features from the Smolin state. A common
feature of all these pure and mixed entangled states is found, i.e., they have
common commuting stabilizers. The differences of qudit-RIC and qubit-RIC
() are also analyzed.Comment: 10 pages, 3 figure
Status epilepticus alters hippocampal PKAβ and PKAγ expression in mice
AbstractObjectivesTo investigate the localization and progressive changes of cyclic-AMP dependent protein kinase (cPKA) in the mouse hippocampus at acute stages during and after pilocarpine induced status epilepticus.MethodsPilocarpine induced status epilepticus mice were sacrificed 30min, 2h or 1 day after the start of a ∼7h lasting status as assessed by video-electroencephalography. Brains were processed for quantitative immunohistochemistry of hippocampal cPKAβ and cPKAγ, and immunohistochemical co-localization of cPKAβ and cPKAγ with calbindin (CB), calretinin (CR), and parvalbumin (PV).ResultsBased on anatomical and morphological assessment, cPKAβ was primarily expressed by principal cells and cPKAγ by interneurons. In CA1, cPKAβ co-localized with 76% of CB, 41% of CR, and 95% of PV-immunopositive cells, while cPKAγ co-localized with 50% of CB, 29% of CR, and 80% of PV-immunopositive cells. Upon induction of status epilepticus, cPKAβ expression was transiently reduced in CA1, whereas cPKAγ expression was sustainably reduced.ConclusioncPKA may play an important role in neuronal hyperexcitability, death and epileptogenesis during and after pilocarpine induced status epilepticus
Twist-4 contributions to the azimuthal asymmetry in SIDIS
We calculate the differential cross section for the unpolarized
semi-inclusive deeply inelastic scattering (SIDIS) process
in leading order (LO) of perturbative QCD and up to twist-4 in power
corrections and study in particular the azimuthal asymmetry . The
final results are expressed in terms of transverse momentum dependent (TMD)
parton matrix elements of the target nucleon up to twist-4. %Under the maximal
two-gluon correlation approximation, these TMD parton matrix elements in a
nucleus %can be expressed terms of a Gaussian convolution of that in a nucleon
with the width given by the jet transport %parameter inside cold nuclei. We
also apply it to $e^-+A \to e^-+q+X$ and illustrate numerically the nuclear
dependence of the azimuthal asymmetry by using a Gaussian ansatz
for the TMD parton matrix elements.Comment: 9 pages, afigur
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