2,347 research outputs found
Collins effect in semi-inclusive deep inelastic scattering process with a He target
We re-examine our previous calculation on the Collins effect in
semi-inclusive deeply inelastic scattering (SIDIS) process with a He
target, and find that our previous treatment on the dilution factors may cause
the results larger than the realistic situation. We thus modify our calculation
in an improved treatment with an updated prediction on the
asymmetry for the JLab 12 GeV under the transverse
momentum dependent (TMD) factorization framework. Meanwhile, we also provide
the prediction of such asymmetry for the JLab 6 GeV and the prediction of the
asymmetry related to pretzelosity.Comment: 10 pages, 4 figures, figures 3 and 4 replaced as Erratu
The azimuthal asymmetry in single longitudinally polarized Drell-Yan process
We study the azimuthal asymmetry in the Drell-Yan
process, when the nucleon is longitudinally polarized. The asymmetry is
contributed by the combination of the Boer-Mulders function and the
longitudinal transversity distribution function. We consider the Drell-Yan
processes by beams colliding on the proton and deuteron targets,
respectively. We calculate the azimuthal asymmetries in these
processes using the Boer-Mulders function and the longitudinal transversity
from spectator models. We show that the study on single polarized
Drell-Yan processes can not only give the information on the new 3-dimensional
parton distribution functions in momentum space, but also shed light on the
chiral-odd structure of the longitudinally polarized nucleon.Comment: 7 pages, 3 figures. Final version for publication in PR
Transversity from two pion interference fragmentation
We present calculation on the azimuthal spin asymmetries for pion pair
production in semi-inclusive deep inelastic scattering (SIDIS) process at both
HERMES and COMPASS kinematics, with transversely polarized proton, deuteron and
neutron targets. We calculate the asymmetry by adopting a set of
parametrization of the interference fragmentation functions and two different
models for the transversity. We find that the result for the proton target is
insensitive to the approaches of the transversity but more helpful to
understand the interference fragmentation functions. However, for the neutron
target, which can be obtained through using deuteron and {He} targets, we
find different predictions for different approaches to the transversity. Thus
probing the two pion interference fragmentation from the neutron can provide us
more interesting information on the transversity.Comment: 15 latex pages, 6 figures, to appear in PR
Pretzelosity and quark orbital angular momentum
We calculate the pretzelosity distribution (), which is one
of the eight leading twist transverse momentum dependent parton distributions
(TMDs), in the light-cone formalism. We find that this quantity has a simple
relation with the quark orbital angular momentum distribution, thus it may
provide a new possibility to access the quark orbital angular momentum inside
the nucleon. The pretzelosity distribution can manifest itself through the
asymmetry in semi-inclusive deep inelastic scattering
process. We calculate the asymmetry at HERMES, COMPASS
and JLab kinematics, and present our prediction on different targets including
the proton, deuteron and neutron targets. Inclusion of transverse momentum cut
in data analysis could significantly enhance the
asymmetry for future measurements.Comment: 20 latex pages, 7 figures, to appear in PR
Device modeling of superconductor transition edge sensors based on the two-fluid theory
In order to support the design and study of sophisticated large scale
transition edge sensor (TES) circuits, we use basic SPICE elements to develop
device models for TESs based on the superfluid-normal fluid theory. In contrast
to previous studies, our device model is not limited to small signal
simulation, and it relies only on device parameters that have clear physical
meaning and can be easily measured. We integrate the device models in design
kits based on powerful EDA tools such as CADENCE and OrCAD, and use them for
versatile simulations of TES circuits. Comparing our simulation results with
published experimental data, we find good agreement which suggests that device
models based on the two-fluid theory can be used to predict the behavior of TES
circuits reliably and hence they are valuable for assisting the design of
sophisticated TES circuits.Comment: 10pages,11figures. Accepted to IEEE Trans. Appl. Supercon
Realization of Zero-Refractive-Index Lens with Ultralow Spherical Aberration
Optical complex materials offer unprecedented opportunity to engineer
fundamental band dispersion which enables novel optoelectronic functionality
and devices. Exploration of photonic Dirac cone at the center of momentum space
has inspired an exceptional characteristic of zero-index, which is similar to
zero effective mass in fermionic Dirac systems. Such all-dielectric zero-index
photonic crystals provide an in-plane mechanism such that the energy of the
propagating waves can be well confined along the chip direction. A
straightforward example is to achieve the anomalous focusing effect without
longitudinal spherical aberration, when the size of zero-index lens is large
enough. Here, we designed and fabricated a prototype of zero-refractive-index
lens by comprising large-area silicon nanopillar array with plane-concave
profile. Near-zero refractive index was quantitatively measured near 1.55 um
through anomalous focusing effect, predictable by effective medium theory. The
zero-index lens was also demonstrated to perform ultralow longitudinal
spherical aberration. Such IC compatible device provides a new route to
integrate all-silicon zero-index materials into optical communication, sensing,
and modulation, and to study fundamental physics on the emergent fields of
topological photonics and valley photonics.Comment: 14 pages, 4 figure
Elevated Levels of Polychlorinated Biphenyls in Plants, Air, and Soils at an E-Waste Site in Southern China and Enantioselective Biotransformation of Chiral PCBs in Plants
- …
