Identification of excited states in the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi>T</mml:mi></mml:mrow><mml:mrow><mml:mi>z</mml:mi></mml:mrow></mml:msub></mml:mrow><mml:mo>=</mml:mo><mml:mo>+</mml:mo><mml:mfrac><mml:mrow><mml:mn>1</mml:mn></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:mfrac></mml:math>nucleus<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow /><mml:mrow><mml:mn

A new approach for the calculation of angular momentum projected potential energy surfaces (AMPPESs) is proposed which combines the projected shell model with a quadrupole constrained relativistic Hartree-Bogoliubov (RHB) theory in which the NL3 effective interaction is chosen for the relativistic mean-field effective Lagrangian and a separable Gogny D1S interaction for the pairing force (QCRHB-NL3 + separable Gogny D1S force theory). We apply this approach to compute the AMPPESs of 80,82,84 Zr nuclei up to high spins and investigate the spin-induced shape transitions and decay out of the superdeformed (SD) bands in these nuclei. We find that the shape transitions occur in 80 Zr and 84 Zr, which are driven by the rotational alignments of the nucleons in the 1g 9/2 orbitals, and a strong shape mixing happens in 82 Zr. Moreover, it is shown that the barrier separating the SD states and normal deformed (or spherical) states becomes lower and narrower for 82 Zr and 84 Zr at high spins, indicating that the decay out of the SD bands could occur at high spins. For 80 Zr, however, there is no decay out of the SD band because the barrier is so high and thick. Meanwhile, the QCRHB-NL3 + separable Gogny D1S force theory is employed to calculate the ground-state potential energy surfaces and the single-particle levels of these nuclei, which in turn are used to determine and analyze the equilibrium shapes and discuss the shape coexistence of these nuclei. In addition, this theory is compared with other state-of-the-art mean-field theories to justify its use to study the ground-state potential energy surfaces of 80,82,84 Zr.

show abstract

“…[18] as well as in the T z = 1/2 nuclei 75 Rb and 77 Sr analyzed in Ref. [70] supports this scenario.…”

Section: Amppess Shape Transitions and Decay Out Of The Sd Bandssupporting

confidence: 60%

Microscopic description of nuclear structure aroundZr80

Zou

Tian

et al. 2010

Phys. Rev. C

View full text Add to dashboard Cite

show abstract

“…The present paper also sheds light on the results of the recent analysis of high spin data in nuclei with T z = 1/2 and 1 [34,35] by means of the conventional mean-field approach that does not explicitly take into account the proton-neutron pairing. It is stated there that "the agreement between theory and experiment can be considered as very good..." These results are consistent with our suggestion that in nuclei with 70 < A < 80 there is strong t = 1 pairing and we want to point out once more our most important message: The fact that the mean-field theory without an explicit pn-pair field works well does by no means imply that there is no t = 1 pn-field.…”

Section: The Role Of T = 1 Proton-neutron Pair-correlationsmentioning

confidence: 78%

“…[32] and the deformations ε = 0.3, γ = 0 and ε 4 = 0 and the monopole pair-fields with ∆ p = ∆ n = 1.1M eV , corresponding to about 80% of the experimental even-odd mass differences, are used. Calculations of equilibrium deformations within the shell-correction method [33][34][35] show that the deformations at low-frequency are characterized by a coexistence of prolate and oblate shapes and softness with respect to the triaxiality parameter γ. At larger frequencies all nuclei tend to take on a near prolate shape with ε = 0.3 − 0.4.…”

Section: Cranked Shell Model Analysis Of Nuclei With a ≈ 72mentioning

confidence: 99%

Cranked shell model and isospin symmetry near N = Z

Frauendorf

Sheikh

1999

Nuclear Physics A

View full text Add to dashboard Cite

A cranked shell model approach for the description of rotational bands in N ≈ Z nuclei is formulated. The isovector neutron-proton pairing is taken into account explicitly. The concept of spontaneous breaking and subsequent restoration of the isospin symmetry turns out to be crucial. The general rules to construct the near yrast-spectra for rotating nuclei are presented. For the model case of particles in a j-shell, it is shown that excitation spectra and the alignment processes are well described as compared to the exact shell model calculation. Realistic cranked shell model calculations are able to describe the experimental spectra of 72,73 Kr and 74 Rb isotopes.

show abstract

“…As for 75 Rb, its measured hyperfine structure permitted an unambiguous groundstate spin assignment. Previously, the ground-state spin for this isotope had only been tentatively assigned as either I = 3/2 or I = 5/2 based on beta and gamma decay studies [15,16]. A comparison of the χ 2 between the two assumptions confirms the I = 3/2 assignment.…”

mentioning

confidence: 87%

First Experimental Determination of the Charge Radius ofRb74and Its Application in Tests of the Unitarity of the Cabibbo-Kobayashi-Maskawa Matrix

et al. 2011

View full text Add to dashboard Cite

Collinear-laser spectroscopy with bunched-beams technique was used for the study of neutron deficient Rb isotopes, out to 74 Rb (N = Z = 37) at TRIUMF. The measured hyperfine coupling constants of 76,78m Rb were in agreement with literature values. The nuclear spin of 75 Rb was confirmed to be I = 3/2, and its hyperfine coupling constants were measured for the first time. The mean-square charge radius of 74 Rb was determined for the first time. This result has improved the isospin symmetry breaking correction term used to calculate the Ft value, with implications for tests of the unitarity of the Cabibbo-Kobayashi-Maskawa matrix.The unitarity of the Cabibbo-Kobayashi-Maskawa (CKM) matrix is one of the cornerstones of the Standard Model of particles and fields. Therefore, the value of all its matrix elements should be measured as accurately and as precisely as possible for the search of new physics phenomena, such as the existence of right-handed currents, extra Z bosons or another quark generation [1]. Indeed, over the years, the value of these matrix elements have been independently determined from different experiments. Superallowed Fermi transitions of nuclear beta decays (0 + → 0 + ) provide the most competitive method to determine the up-down quark matrix element V ud [2]. Assuming the Conserved Vector Current (CVC) hypothesis, which states that the vector coupling constant of semileptonic weak interactions G V remains unchanged in all superallowed beta transitions, this matrix element can be obtained from V ud = G V /G F , where G F is the weak interaction constant for leptonic muon decay, and G V is defined in terms of the corrected F t value of the beta decay [3],.The f t value is related to the measured half-lives, branching ratios and the Q value of the beta decay. The terms δ ′ R and δ N S are transition-dependent theoretical corrections, and δ C is the isospin symmetry breaking term [4]. The latter is purely nuclear structure dependent, the error of which normally dominates the uncertainty on the F t value. The term ∆ V R is transition-independent and K is a constant. Evaluations of the isospin symmetry breaking correction involve the 13 most precisely measured superallowed beta emitters which span a wide Z range (6 ≤ Z ≤ 37) [4]. Within the existing theoretical approaches used to determine δ C [5] the leading source of uncertainty stems from the incomplete knowledge of the radial extension of the charge distribution of the parent and daughter isotopes. Where experimental data are unavailable, the nuclear structure input is based on extrapolations of the existing models. For the lighter elements, shell model calculations with a Saxon-Woods potential provide a more consistent framework from which this information can be reliably extracted. However, with higher Z, the orbitals of the f p shell are filled and shell model calculations become computationally difficult, due to the larger model space required. In addition, effective interactions become less reliable [6]. There have been many theoretical ef...

show abstract

Identification of excited states in theTz=+12nucleus

Cited by 19 publications

References 23 publications

Microscopic description of nuclear structure aroundZr80

Microscopic description of nuclear structure aroundZr80

Cranked shell model and isospin symmetry near N = Z

First Experimental Determination of the Charge Radius ofRb74and Its Application in Tests of the Unitarity of the Cabibbo-Kobayashi-Maskawa Matrix

Contact Info

Product

Resources

About