Search arXivSearch

arXiv · 0902.0267

Branching ratios of $α$-decay to excited states of even-even nuclei

Abstract

Branching ratios of $α$-decay to members of the ground state rotational band and excited 0$^{+}$ states of even-even nuclei are calculated in the framework of the generalized liquid drop model (GLDM) by taking into account the angular momentum of the $α$-particle and the excitation probability of the daughter nucleus. The calculation covers isotopic chains from Hg to Fm in the mass regions $180< A <202$ and A$\geq 224$. The calculated branching ratios of the $α$-transitions are in good agreement with the experimental data and some useful predictions are provided for future experiments.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Y. Z. Wang, H. F. Zhang, J. M. Dong, G. Royer. 2009-02-02. Branching ratios of $α$-decay to excited states of even-even nuclei. https://doi.org/10.1103/physrevc.79.014316

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

Centrality dependence of charged-particle pseudorapidity density at midrapidity in Pb-Pb collisions at $\mathbf{\sqrt{\textit{s}_{\rm NN}} = 5.36}$ TeV

The ALICE Collaboration reports its first LHC Run 3 measurements of charged-particle pseudorapidity density at midrapidity in Pb-Pb collisions at a centre-of-mass energy per nucleon pair of $\sqrt{s_{\mathrm{NN}}}=5.36$ TeV. Particle multiplicity in high-energy collisions characterises the system geometry, constrains particle-production mechanisms, and is used to estimate initial energy density. Multiplicity also acts as a reference for subsequent measurements as a function of centrality. In this letter, for the first time, charged particles are reconstructed using the upgraded ALICE Inner Tracking System and Time Projection Chamber, while the collision centrality is determined by measuring charged-particle multiplicities with the Fast Interaction Trigger system. Pseudorapidity density, ${\rm d}N_{\rm ch}/{\rm d}η$, is presented, averaged over events, for various centrality classes. Results are shown as a function of pseudorapidity and the average number of participating nucleons ($\langle N_{\mathrm{part}}\rangle$) in the collision. The average charged-particle pseudorapidity density ($\langle {\rm d}N_{\rm ch}/{\rm d}η\rangle$) at midrapidity ($|η|<0.5$) is 2010 $\pm$ 53 for the 5% most central collisions. The value of $\langle {\rm d}N_{\rm ch}/{\rm d}η\rangle$ normalised to $\langle N_{\mathrm{part}}\rangle/2$ as a function of $\sqrt{s_{\mathrm{NN}}}$ follows the trend established in previous measurements in heavy-ion collisions. Theoretical models based on mechanisms for particle production in nuclear collisions that involve the formation of quark-gluon plasma medium and models based on individual nucleon-nucleon interactions are compared to the data.

nucl-ex

Observation of a magnetic shift in neutron whispering-gallery states

We developed experimental and theoretical methods to create and describe high-resolution whispering-gallery interference patterns and show the feasibility of measuring their small shifts by external interactions. Such experiments can be used to search for extra fundamental interactions, time parity violations, nonzero electric charges, precisely measuring the gravitational properties of (anti)matter, parity violations, neutron polarizability, quantum reflection, surface state effects, etc. Here, we measure a magnetic shift of such a neutron pattern $δg/g\sim (6.5 \pm 0.8_{st} \pm 1.2_{sys}) \cdot 10^{-4}$, and our sensitivity to spin-dependent differences between the scattering lengths was $δb_n/b_n \sim 10^{-4}$.

nucl-ex

Photoneutron reactions on $^{165}$Ho and $^{169}$Tm in the giant dipole resonance region

Photoneutron reactions were investigated for the deformed $^{165}$Ho and $^{169}$Tm nuclei from the vicinity of the neutron emission threshold up to $\sim$40~MeV, well above the giant dipole resonance (GDR) region, using quasimonochromatic laser Compton scattering $γ$-ray beams provided at the NewSUBARU facility, Japan. A high-and-flat efficiency moderated array of $^3$He counters was used for the neutron detection and an associated neutron multiplicity sorting method for extracting the $(γ,\,1nX)$, $(γ,\,2nX)$, $(γ,\,3nX)$ and $(γ,\,4nX)$ reaction cross sections and average neutron emission energies. The present $^{165}$Ho cross sections were compared to existing data, revealing discrepancies with the Saclay multiplicity sorting results and an overall 10$\%$ strength difference with the Livermore ones. There are no other data for $^{169}$Tm. GDR parameters based on phenomenological Lorentzian models were extracted by fitting the present $σ(γ,\,Sn)$ data with adjustments for the missing contribution of charged-particle-only reactions not observed experimentally. For both nuclei we observed high energy structures at 20-25~MeV, matching giant quadrupole resonance KMFR predictions. Based on the present centroid energies of the first and second GDR peaks, hydrodynamic model predictions gave intrinsic electric quadrupole moments of +7.00(34)~b and +7.38(28)~b for the ground states of $^{165}$Ho and $^{169}$Tm, respectively. The present experimental excitation functions and photoneutron energies were compared to statistical model calculations. Using the EMPIRE code, we performed a sensitivity test to phenomenological models of photon strength functions and nuclear level densities. The TALYS code was used to reproduce the present experimental $(γ,\,inX)$ cross sections and average neutron energies using microscopic nuclear level density models.

nucl-ex