543 research outputs found
A consistent analysis of (e,e'p) and (d,3He) experiments
The apparent discrepancy between spectroscopic factors obtained in (e,e'p)
and (d,3He) experiments is investigated. This is performed first for
48Ca(e,e'p) and 48Ca(d,3He) experiments and then for other nuclei. It is shown
that the discrepancy disappears if the (d,3He) experiments are re-analyzed with
a non-local finite range DWBA analysis with a bound-state wave function that is
obtained from (e,e'p) experiments.Comment: 23 pages, 7 figure
The Zero-Removing Property and Lagrange-Type Interpolation Series
The classical Kramer sampling theorem, which provides a method for obtaining orthogonal sampling formulas, can be formulated in a more general nonorthogonal setting. In this setting, a challenging problem is to characterize the situations when the obtained nonorthogonal sampling formulas can be expressed as Lagrange-type interpolation series. In this article a necessary and sufficient condition is given in terms of the zero removing property. Roughly speaking, this property concerns the stability of the sampled functions on removing a finite number of their zeros
Dynamics of cholesteric structures in an electric field
Motivated by Lehmann-like rotation phenomena in cholesteric drops we study
the transverse drift of two types of cholesteric fingers, which form rotating
spirals in thin layers of cholesteric liquid crystal in an ac or dc electric
field. We show that electrohydrodynamic effects induced by Carr-Helfrich charge
separation or flexoelectric charge generation can describe the drift of
cholesteric fingers. We argue that the observed Lehmann-like phenomena can be
understood on the same basis.Comment: 4 pages, 4 figures, submitted to PR
On the speed of convergence to stationarity of the Erlang loss system
We consider the Erlang loss system, characterized by servers, Poisson arrivals and exponential service times, and allow the arrival rate to be a function of We discuss representations and bounds for the rate of convergence to stationarity of the number of customers in the system, and display some bounds for the total variation distance between the time-dependent and stationary distributions. We also pay attention to time-dependent rates
Higgs-Boson Production Associated with a Single Bottom Quark in Supersymmetric QCD
Due to the enhancement of the couplings between Higgs boson and bottom quarks
in the minimal sypersymmetric standard model (MSSM), the cross section of the
process pp(p\bar{p}) \to h^0b(h^0\bar{b})+X at hadron colliders can be
considerably enhanced. We investigated the production of Higgs boson associated
with a single high-p_T bottom quark via subprocess bg(\bar{b}g) \to
h^0b(h^0\bar{b}) at hadron colliders including the next-to-leading order (NLO)
QCD corrections in MSSM. We find that the NLO QCD correction in the MSSM
reaches 50%-70% at the LHC and 60%-85% at the Fermilab Tevatron in our chosen
parameter space.Comment: accepted by Phys. Rev.
Spectroscopic Factors in Ca and Pb from : Fully Relativistic Analysis
We present results for spectroscopic factors of the outermost shells in
Ca and Pb, which have been derived from the comparison between
the available quasielastic () data from NIKHEF-K and the corresponding
calculated cross-sections obtained within a fully relativistic formalism. We
include exactly the effect of Coulomb distortion on the electron wave functions
and discuss its role in the extraction of the spectroscopic factors from
experiment. Without any adjustable parameter, we find spectroscopic factors of
about 70\%, consistent with theoretical predictions. We compare our results
with previous relativistic and nonrelativistic analyses of () data. In
addition to Coulomb distortion effects we discuss different choices of the
nucleon current operator and also analyze the effects due to the relativistic
treatment of the outgoing-distorted and bound nucleon wave functions.Comment: 9 pages RevTeX, 5 figures can be obtained from the author
Emergent global oscillations in heterogeneous excitable media: The example of pancreatic beta cells
Using the standard van der Pol-FitzHugh-Nagumo excitable medium model I
demonstrate a novel generic mechanism, diversity, that provokes the emergence
of global oscillations from individually quiescent elements in heterogeneous
excitable media. This mechanism may be operating in the mammalian pancreas,
where excitable beta cells, quiescent when isolated, are found to oscillate
when coupled despite the absence of a pacemaker region.Comment: See home page http://lec.ugr.es/~julya
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