39,632 research outputs found
Comment on "Mass and K Lambda coupling of N*(1535)"
It is argued in [1] that when the strong coupling to the K Lambda channel is
considered, Breit-Wigner mass of the lightest orbital excitation of the nucleon
N(1535) shifts to a lower value. The new value turned out to be smaller than
the mass of the lightest radial excitation N(1440), which effectively solved
the long-standing problem of conventional constituent quark models. In this
Comment we show that it is not the Breit-Wigner mass of N(1535) that is
decreased, but its bare mass.
[1] B. C. Liu and B. S. Zou, Phys. Rev. Lett. 96, 042002 (2006).Comment: 3 pages, comment on "Mass and K Lambda coupling of N*(1535)", B. C.
Liu and B. S. Zou, Phys. Rev. Lett. 96, 042002 (2006
Effects of interorbital hopping on orbital fluctuations and metal-insulator transitions: Extended linearized dynamical mean-field theory
We study the effects of interorbital hopping on orbital fluctuations and
Mott-Hubbard metal-insulator transition (MIT) in the two-orbital Hubbard model
within the extended linearized dynamical mean-field theory. By mapping the
model onto an effective model with different bandwidths through the canonical
transformation, we find that at half-filling, the increases of the interorbital
Coulomb interaction and the Hund's coupling drive the MIT, and
the critical for MIT increases with the lift of the inter-orbital
hopping integral . Meanwhile at quarter filling and in the strong
correlation regime, the system without exhibits MIT with the
decreasing of , and favors the orbital liquid ground state. However, the
system transits from metal to insulator with the increasing of t,
accompanied with the rising of the orbital order parameter. These results show
the important role of the interorbital hopping in the orbital fluctuation and
orbital ordering.Comment: 7 pages, 6 figure
Subthreshold rho contribution in J/psi decay to omega pion pion and Kaon anti-Kaon pion
We carry out a theoretical and Monte Carlo study on the decays into
and through intermediate subthreshold meson
by using SU(3)-symmetric Lagrangian approach. It is found that the subthreshold
contribution is not negligible and may have significant influence on
partial wave analysis of resonances in these channels, especially near the
and thresholds.Comment: 12 pages, 5 figure
Confined Multilamellae Prefer Cylindrical Morphology
By evaporating a drop of lipid dispersion we generate the myelin morphology
often seen in dissolving surfactant powders. We explain these puzzling
nonequilibrium structures using a geometric argument: The bilayer repeat
spacing increases and thus the repulsion between bilayers decreases when a
multilamellar disk is converted into a myelin without gain or loss of material
and with number of bilayers unchanged. Sufficient reduction in bilayer
repulsion can compensate for the cost in curvature energy, leading to a net
stability of the myelin structure. A numerical estimate predicts the degree of
dehydration required to favor myelin structures over flat lamellae.Comment: 6 pages, 3 figures, submitted to Euro. Phys. J.
Catalytic RNA and synthesis of the peptide bond
We are studying whether the L-19 IVS ribozyme from Tetrahymena thermophila can catalyze the formation of the peptide bond when it is supplied with synthetic aminoacyl oligonucleotides. If this reaction works, it could give us some insight into the mechanism of peptide bond formation and the origin of coded protein synthesis. Two short oligoribonucleotides, CCCCC and a protected form of CCCCU were prepared; the former was made by the controlled hydrolysis of Poly(C), and the later by multistep chemical synthesis from the protected monomers. The homopentamer was then aminocylated using C-14 labelled Boc-protected glycine imidazolide. This aminoacylated oligo-nucleotide has now been shown to enter the active site of the L-19 IVS, and aminoacyl transfer, and peptide bond formation reactions are being sought. Our synthesis of CCCCU made us aware of the inadequacy of many of the 2'- hydroxyl protecting groups that are in use today and we therefore designed a new 2'- protecting group that is presently being tested
Double pion production in and collisions
With an effective Lagrangian approach, we give a full analysis on the and reactions by exploring the roles of
various resonances with mass up to 1.72 GeV. We find large contributions from
, , and resonances. Our
calculations also indicate sizeable contributions from nucleon poles for the
energies close to the threshold. A good description to the existing data of
different isospin channels of and
for beam energies up to 2.2 GeV is reached. Our results provide important
implications to the ABC effect and guildlines to the future experimental
projects at COSY, HADES and HIRFL-CSR. We point out that the \={P}ANDA at FAIR
could be an essential place for studying the properties of baryon resonances
and the data with baryon and anti-baryon in final states are worth analyzing.Comment: Invited plenary talk at the 11th International Workshop on Meson
Production, Properties and Interaction (MESON2010), 10-15 June, 2010, Krakow,
Polan
- …