arXiv subjects

K. Hara

Publications and source records attributed to K. Hara.

59 records · Page 4Linked to original sources

arXiv2000

Gamow-Teller Strengths of the Inverse-Beta Transition 176Yb --> 176Lu for Spectroscopy of Proton-Proton and other sub-MeV Solar Neutrinos

Discrete Gamow-Teller (GT) transitions, 176Yb-->176Lu at low excitation energies have been measured via the (3He,t) reaction at 450 MeV and at 0 degrees. For 176Yb, two low-lying states are observed, setting low thresholds Q(neutrino)=301 and 445 keV for neutrino capture. Capture rates estimated from the measured GT strengths, the simple two-state excitation structure, and the low Q(neutrino) in Yb--Lu indicate that Yb-based neutrino-detectors are well suited for a direct measurement of the complete sub-MeV solar electron-neutrino spectrum (including pp neutrinos) where definitive effects of flavor conversion are expected.

nucl-ex↗

arXiv1998

Triaxial projected shell model approach

The projected shell model analysis is carried out using the triaxial Nilsson+BCS basis. It is demonstrated that, for an accurate description of the moments of inertia in the transitional region, it is necessary to take the triaxiality into account and perform the three-dimensional angular-momentum projection from the triaxial Nilsson+BCS intrinsic wavefunction.

nucl-th↗

arXiv1997

Analysis of the superdefomed rotational bands

All available experimental data for the $ΔI=2$ transition energies in superdeformed bands are analyzed by using a new one-point formula. The existence of deviations from the smooth behavior is confirmed in many bands. However, we stress that one cannot necessarily speak about staggering patterns as they are mostly irregular. Simulations of the experimental data suggest that the irregularities may stem from the presence of irregular kinks in the rotational spectra. This could be a clue but, at the moment, where such kinks come from is an open question.

nucl-th↗

arXiv1997

Analysis of Molecular Rotational Spectra

Rotational spectra of diatomic molecules measured in the high-precision experiments are analyzed. Such a spectrum is usually fitted by an 8th order polynomial in spin. In fact, from the theoretical point of view, the rotational spectrum is expected to be a smooth function of spin. Thus, fitting the rotational spectrum in terms of a low order polynomial in spin seems to be justified. However, this is not what we found in the present work. We show that the measured spectrum is not necessarily a smooth function of the spin, which is quite surprising. Whether or not it indicates the presence of some hidden physics is an open question.

physics.atom-ph↗

arXiv1996

Analysis of Delta I =2 staggering in nuclear rotational spectra

A method is proposed and tested for the analysis of Delta I=2 staggering observed in nuclear rotational bands. We examine six super- and hyper-deformed bands, among which that of 149Gd and possibly of 147Gd seem to exhibit real staggering. However, we emphasize that the presence of staggering may not necessarily imply the occurrence of bifurcation. It is also shown that a similar staggering seen in normally deformed bands is a manifestation of band crossings. A more extensive analysis is planned.

nucl-th↗