arXiv subjects

P. B. Siegel

Publications and source records attributed to P. B. Siegel.

3 recordsLinked to original sources

arXiv2004

Nonstationary time series analysis of heart rate variability

An analysis of the RR-interval time series, $t_i$, is presented for the case in which the average time, $\bar{t}$, changes slowly. In particular, $\bar{t}$ and a short-time scale variability parameter, $V$, are simultaneously measured while $\bar{t}$ decreases for subjects in the reclined position. The initial decrease in $\bar{t}$ is usually linear with $V$ yielding parameters that can be related to physiological quantities.

q-bio.QM↗

arXiv1995

Chiral Dynamics and the $S_{11}(1535)$ Nucleon Resonance

The $SU(3)$ chiral effective lagrangian at next-to-leading order is applied to the S-wave meson-baryon interaction in the energy range around the $ηN$ threshold. Potentials are derived from this lagrangian and used in a coupled channel calculation of the $πN$, $ηN$, $K Λ$, $K Σ$ system in the isospin-$1/2$, $l=0$ partial wave. Using the same parameters as obtained from a fit to the low energy $\overline{K} N$ data it is found that a quasi-bound $K Σ$-state is formed, with properties remarkably similar to the $S_{11}(1535)$ nucleon resonance. In particular, we find a large partial decay width into $ηN$ consistent with the empirical data.

nucl-th↗

arXiv1995

Chiral Dynamics and the Low Energy Kaon-Nucleon Interaction

We examine the meson-baryon interaction in the strangeness S=-1 sector using an effective chiral Lagrangian. Potentials are derived from this Lagrangian and used in a coupled-channel calculation of the low energy observables. The potentials are constructed such that in the Born approximation the s-wave scattering amplitude is the same as that given by the effective chiral Lagrangian, up to order $q^2$. Comparison is made with the available low energy hadronic data of the coupled $K^-p, Σπ, Λπ$ system, which includes the $Λ(1405)$ resonance, $K^-p$ elastic and inelastic scattering, and the threshold branching ratios of the $K^-p$ decay. Good fits to the experimental data and estimates of previously unknown Lagrangian parameters are obtained.

nucl-th↗