53,331 research outputs found
Groundstate with Zero Eigenvalue for Generalized Sombrero-shaped Potential in -dimensional Space
Based on an iterative method for solving the goundstate of Schroedinger
equation, it is found that a kind of generalized Sombrero-shaped potentials in
N-dimensional space has groundstates with zero eigenvalue. The restrictions on
the parameters in the potential are discussed.Comment: 8 pages, 3 figure
Masses of the Bottom-Charm Hybrid States
QCD sum rules are used to study the mass spectrum of bottom-charm hybrid
systems. The correlation functions and the spectral densities are
calculated up to dimension six condensates at leading order of for
several quantum numbers. After performing the QCD sum rule analysis, we
predict the masses of the
bottom-charm hybrids. These mass predictions show a similar supermultiplet
structure as the bottomonium and charmonium hybrids. Using the QCD sum-rule
mass predictions we analyze the possible hadronic decay patterns of the , and hybrids including the open-flavour and
hidden-flavour mechanisms.Comment: 14 pages, 8 figures, 6 tables. Version to appear in Journal of
Physics
Exotic open-flavor , and , tetraquark states
We study the exotic , and
, systems by constructing the
corresponding tetraquark currents with and . After investigating
the two-point correlation functions and the spectral densities, we perform QCD
sum rule analysis and extract the masses of these open-flavor tetraquark
states. Our results indicate that the masses of both the scalar and axial
vector tetraquark states are about GeV for the
system and GeV for the system. For the
tetraquark states with and , their masses are
extracted to be around GeV. The masses for the scalar and axial vector
states are GeV and GeV, respectively. The
tetraquark states and lie below the
thresholds of and
respectively, but they can decay into plus a light meson. However, the
tetraquark states and lie below the
and thresholds,
suggesting dominantly weak decay mechanisms.Comment: 18 pages, 7 figures, 4 table
High efficiency transfection of thymic epithelial cell lines and primary thymic epithelial cells by Nucleofection
Thymic epithelial cells (TECs) are required for the development and differentiation of T cells and are sufficient for the positive and negative selection of developing T cells. Although TECs play a critical role in T cell biology, simple, efficient and readily scalable methods for the transfection of TEC lines and primary TECs have not been described. We tested the efficiency of Nucleofection for the transfection of 4 different mouse thymic epithelial cell lines that had been derived from cortical or medullary epithelium. We also tested primary mouse thymic epithelial cells isolated from fetal and postnatal stages. We found that Nucleofection was highly efficient for the transfection of thymic epithelial cells, with transfection efficiencies of 30-70% for the cell lines and 15-35% for primary TECs with low amounts of cell death. Efficient transfection by Nucleofection can be performed with established cortical and medullary thymic epithelial cell lines as well as primary TECs isolated from E15.5 day fetal thymus or postnatal day 3 or 30 thymus tissue. The high efficiency of Nucleofection for TEC transfection will enable the use of TEC lines in high throughput transfection studies and simplifies the transfection of primary TECs for in vitro or in vivo analysis
Relative entropy of entanglement for certain multipartite mixed states
We prove conjectures on the relative entropy of entanglement (REE) for two
families of multipartite qubit states. Thus, analytic expressions of REE for
these families of states can be given. The first family of states are composed
of mixture of some permutation-invariant multi-qubit states. The results
generalized to multi-qudit states are also shown to hold. The second family of
states contain D\"ur's bound entangled states. Along the way, we have discussed
the relation of REE to two other measures: robustness of entanglement and
geometric measure of entanglement, slightly extending previous results.Comment: Single column, 22 pages, 9 figures, comments welcom
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