1,257 research outputs found
Pseudogap, Superconducting Energy Scale, and Fermi Arcs in Underdoped Cuprate Superconductors
Through the measurements of magnetic field dependence of specific heat in
in zero temperature limit, we determined the nodal slope
of the quasiparticle gap. It is found that has a very
similar doping dependence of the pseudogap temperature or value
. Meanwhile the virtual maximum gap at () derived from
is found to follow the simple relation upon
changing the doping concentration. This strongly suggests a close relationship
between the pseudogap and superconductivity. It is further found that the
superconducting transition temperature is determined by both the residual
density of states of the pseudogap phase and the nodal gap slope in the zero
temperature limit, namely, , where
is the extracted zero temperature value of the normal state
specific heat coefficient which is proportional to the size of the residual
Fermi arc . This manifests that the superconductivity may be formed by
forming a new gap on the Fermi arcs near nodes below . These observations
mimic the key predictions of the SU(2) slave boson theory based on the general
resonating-valence-bond (RVB) picture.Comment: 6 pages, 6 figures, to be published in Phys. Rev.
Topcolor assisted technicolor models and muon anomalous magnetic moment
We discuss and estimate the contributions of the new particles predicted by
topcolor assisted technicolor(TC2) models to the muon anomalous magnetic moment
. Our results show that the contributions of Pseudo Goldstone bosons
are very small which can be safely ignored. The main contributions come from
the ETC gauge boson and topcolor gauge boson . If we
demand that the mass of is consistent with other experimental
constrains, its contributions are smaller than that of . With
reasonable values of the parameters in TC2 models, the observed BNL results for
could be explained.Comment: latex file, 11 pages, several figures and references adde
Probing Topcolor-Assisted Technicolor from Top-Charm Associated Production at LHC
We propose to probe the topcolor-assisted technicolor (TC2) model from the
top-charm associated productions at the LHC, which are highly suppressed in the
Standard Model. Due to the flavor-changing couplings of the top quark with the
scalars (top-pions and top-Higgs) in TC2 model, the top-charm associated
productions can occur via both the s-channel and t-channel parton processes by
exchanging a scalar field at the LHC. We examined these processes through Monte
Carlo simulation and found that they can reach the observable level at the LHC
in quite a large part of the parameter space of the TC2 model.Comment: Version to appear in PRD (Rapid Communication
Two-loop Barr-Zee type Contributions to in the MSSM
We consider the contribution of a two-loop Barr-Zee type diagram to
in the minimal supersymmetric standard model (MSSM). At relatively
large , we show that the contribution of light third generation
scalar fermions and neutral CP-even Higgs, , can easily explain the
very recent BNL experimental data. In our analysis prefers negative
and positive . It is more sensitive to the chirality flipping
h^0(H^0)\wt{f}_R^*\wt{f}_L rather than chirality conserving couplings.Comment: 10 pages, 5 figures, references adde
Optimiranje podloge za proizvodnju 5\u27-fosfodiesteraze iz plijesni Penicillium citrinum primjenom metode odzivnih površina
Medium optimization for 5’-phosphodiesterase production from Penicillium citrinum was studied by applying one-factor-at-a-time method, orthogonal array method and response surface methodology in this paper. The one-factor-at-a-time method was used to study the effects of carbon, nitrogen, phosphorus and metal ion sources on 5’-phosphodiesterase production. Among various carbon and nitrogen sources used, glucose and peptone were the most suitable substances for 5’-phosphodiesterase production, respectively. Subsequently, the concentrations of glucose, peptone, groundnut meal, Zn2+ and KH2PO4 were optimized using the orthogonal array method. Response surface methodology was also applied for medium optimization. Glucose concentration (X1), peptone concentration (X2) and groundnut meal (X3) were selected as the independent variables. Results showed that the regression models adequately explained the data variation and represented the actual relationships between the parameters and responses. The optimum conditions were glucose at a fraction of 6.5 %, peptone at a fraction of 0.45 % and groundnut meal at a fraction of 1.0 %. Maximum enzyme activity was 353 U/mL under the optimum conditions. Maximum 5’-phosphodiesterase activity in media optimized by orthogonal method and response surface methodology was about 1.286 and 1.456 times, respectively, greater than in the medium optimized by one-factor-at-a-time method.U ovom je radu provedeno optimiranje podloge za proizvodnju 5\u27-fosfodiesteraze iz plijesni Penicillium citrinum trima metodama: jednofaktorskom, ortogononalnom i metodom odzivnih površina. Primjenom jednofaktorske metode istražen je utjecaj izvora ugljika, dušika, fosfora i iona metala na proizvodnju 5\u27-fosfodiesteraze. Upotrijebljeni su razni izvori ugljika i dušika, među kojima su glukoza i pepton bili najprikladniji za proizvodnju 5\u27-fosfodiesteraze. Nakon toga su, primjenom ortogonalne metode, optimirane koncentracije glukoze, peptona, sačme od neoljuštena orašca, Zn2+ iona i KH2PO4. Optimiranje podloge provedeno je i metodom odzivnih površina. Kao nezavisne varijable određene su koncentracija glukoze (X1), peptona (X2) i sačme orašca (X3). Pokazalo se da su regresijski modeli bili najprikladniji za objašnjenje rezultata i prikazivanje stvarnog odnosa parametara i odziva. Optimalni su uvjeti postignuti s udjelom glukoze od 6,5 %, peptona 0,45 % i sačme orašca 1,0 %. Maksimalna aktivnost enzima 5\u27-fosfodiesteraze u optimalnim uvjetima iznosila je 353 U/mL, te je u podlozi optimiranoj ortogonalnom metodom bila 1,286 puta veća, a metodom odzivnih površina 1,456 puta veća nego u podlozi optimiranoj jednofaktorskom metodom
Conformal Affine Toda Soliton and Moduli of IIB Superstring on
In this paper we interpret the hidden symmetry of the moduli space of IIB
superstring on in terms of the chiral embedding in
, which turns to be the conformal affine Toda model.
We review how the position of poles in the Riemann-Hilbert formulation
of dressing transformation and how the value of loop parameters in the
vertex operator of affine algebra determines the moduli space of the soliton
solutions, which describes the moduli space of the Green-Schwarz superstring.
We show also how this affine SU(4) symmetry affinize the conformal symmetry in
the twistor space, and how a soliton string corresponds to a Robinson
congruence with twist and dilation spin coefficients of twistor.Comment: Final version, Misprints corrected, Note adde
Detecting quantitative trait loci for water use efficiency in rice using a recombinant inbred line population
Study on the rare radiative decay in the standard model and multiscale walking technicolor model
Applying the perturbative QCD ( PQCD ) method, we study the decay
in the standard model and multiscale walking
technicolor model. In the SM, we find that the contribution of weak
annihilation is more important than that of the electromagnetic penguin. The
presence of Pseudo-Goldstone-Bosons in the MWTCM leads to a large enhancement
in the rate of , but this model is in conflict with
the branching ratio of ( ) and the CLEO data
on the branching ratio BR ( ). If topcolor is further
introduced, the calculated results in the topcolor assisted MWTCM can be
suppressed and be in agreement with the CLEO data for a certain range of the
parameters.Comment: 16 pages, Latex, no macros, 1 figure(in Latex), hard copy is
available upon request. to appear in Phys. Rev.
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