Boson-conserving one-nucleon transfer operator in the interacting boson model

The boson-conserving one-nucleon transfer operator in the interacting boson model (IBA) is reanalyzed. Extra terms are added to the usual form used for that operator. These new terms change generalized seniority by one unit, as the ones considered up to now. The results obtained using the new form for the transfer operator are compared with those obtained with the traditional form in a simple case involving the pseudo-spin Bose-Fermi symmetry $U^{B}(6) \otimes U^F(12)$ in its $U^{BF}(5) \otimes U^F(2)$ limit. Sizeable differences are found. These results are of relevance in the study of transfer reactions to check nuclear supersymmetry and in the description of (\beta)-decay within IBA.Comment: 13 pages, 1 table, 0 figures. To be published in Phys. Rev.

β-decay rates of 121–131Cs in the microscopic interacting boson-fermion model

β -decay rates of 121–131 Cs have been calculated in the framework of the neutron-proton interacting boson- fermion model (IBFM-2). For odd- A nuclei, the decay operator can be written in a relatively simple form in terms of the one-nucleon transfer operator. Previous studies of β decay in IBFM-2 were based on a transfer operator obtained by using the number operator approximation (NOA). In this work a new form of the one-nucleon transfer operator, derived microscopically without the NOA approximation, is used. The results from both approaches are compared and show that the deviation from experimental data is reduced without using the NOA approximation. Indications about the renormalization of the Fermi and Gamow-Teller matrix elements are discussed. This is a further step toward a more complete description of low-lying states in medium and heavy nuclei which is necessary to compute reliable matrix elements in studies of current active interest such as double- β decay or neutrino absorption experimentsMinisterio de Economía y Competitividad (España) FIS2014-53448-C2-1-PConsejería de Economía, Innovación, Ciencia y Empleo de la Junta de Andalucía FQM-160 P11-FQM-763

Relationship between X(5)-models and the interacting boson model

The connections between the X(5)-models (the original X(5) using an infinite square well, X(5)-$\beta^8$, X(5)-$\beta^6$, X(5)-$\beta^4$, and X(5)-$\beta^2$), based on particular solutions of the geometrical Bohr Hamiltonian with harmonic potential in the $\gamma$ degree of freedom, and the interacting boson model (IBM) are explored. This work is the natural extension of the work presented in [1] for the E(5)-models. For that purpose, a quite general one- and two-body IBM Hamiltonian is used and a numerical fit to the different X(5)-models energies is performed, later on the obtained wave functions are used to calculate B(E2) transition rates. It is shown that within the IBM one can reproduce well the results for energies and B(E2) transition rates obtained with all these X(5)-models, although the agreement is not so impressive as for the E(5)-models. From the fitted IBM parameters the corresponding energy surface can be extracted and it is obtained that, surprisingly, only the X(5) case corresponds in the moderate large N limit to an energy surface very close to the one expected for a critical point, while the rest of models seat a little farther.Comment: Accepted in Physical Review

Data for the modelling of the future power system with a high share of variable renewable energy

Energy and power system models have become necessary tools that provide challenges and technical and economic solutions for integrating high shares of Variable Renewable Energy. Models are focused on analysing strategies of power systems to achieve their decarbonisation targets. The data presented in this paper includes the model algorithm, inputs, equations, modelling assumptions, supplementary materials, and results of the simulations supporting the research article titled “Facing the high share of variable renewable energy in the power system: flexibility and stability requirements”. The analysis is based on data from the system operator of one of the European Union member states (Spain). The developed model allows making projections and calculations to obtain the power generation of each technology, the international interconnections, inertia, emissions, system costs and flexibility requirements of new technologies. These data can be used for energy policy development or decision making on power capacity and the balancing needs of the future power system.Ministerio de Ciencia e Innovación PID2020-114725RA-I00Universidad de Sevilla VI PPIT-USPlan nacional I+D+I CTM2016-78089-RJunta de Andalucía P18-RT-451

Nuclear masses set bounds on quantum chaos

It has been suggested that chaotic motion inside the nucleus may significantly limit the accuracy with which nuclear masses can be calculated. Using a power spectrum analysis we show that the inclusion of additional physical contributions in mass calculations, through many-body interactions or local information, removes the chaotic signal in the discrepancies between calculated and measured masses. Furthermore, a systematic application of global mass formulas and of a set of relationships among neighboring nuclei to more than 2000 nuclear masses allows to set an unambiguous upper bound for the average errors in calculated masses which turn out to be almost an order of magnitude smaller than estimated chaotic components.Comment: 4 pages, Accepted for publication in Physical Review Letter

Immediate Effects of Upper Cervical Translatoric Mobilization on Cervical Mobility and Pressure Pain Threshold in Patients With Cervicogenic Headache: A Randomized Controlled Trial

Objective The purpose of this study was to evaluate the immediate effects of upper cervical translatoric spinal mobilization (UC-TSM) on cervical mobility and pressure pain threshold in subjects with cervicogenic headache (CEH). Methods Eighty-two volunteers (41.54 ± 15.29 years, 20 male and 62 female) with CEH participated in the study and were randomly divided into the control and treatment groups. The treatment group received UC-TSM and the control group remained in the same position for the same time as the UC-TSM group, but received no treatment. Cervical mobility (active cervical mobility and flexion-rotation test), pressure pain thresholds over upper trapezius muscles, C2-3 zygapophyseal joints and suboccipital muscles, and current headache intensity (visual analog scale) were measured before and immediately after the intervention by 2 blinded investigators. Results After the intervention, UC-TSM group exhibited significant increases in total cervical mobility (P =.002, d = 0.16) and the flexion–rotation test (P .05). Nevertheless, there was a significantly lower intensity of headache in the UC-TSM group (P =.039, d = 0.57). Conclusions Upper cervical translatoric spinal mobilization intervention increased upper, and exhibited a tendency to improve general, cervical range of motion and induce immediate headache relief in subjects with CEH

Investigation of double beta decay with the NEMO-3 detector

The double beta decay experiment NEMO~3 has been taking data since February 2003. The aim of this experiment is to search for neutrinoless ($0\nu\beta\beta$) decay and investigate two neutrino double beta decay in seven different isotopically enriched samples ($^{100}$Mo, $^{82}$Se, $^{48}$Ca, $^{96}$Zr, $^{116}$Cd, $^{130}$Te and $^{150}$Nd). After analysis of the data corresponding to 3.75 y, no evidence for $0\nu\beta\beta$ decay in the $^{100}$Mo and $^{82}$Se samples was found. The half-life limits at the 90% C.L. are $1.1\cdot 10^{24}$ y and $3.6\cdot 10^{23}$ y, respectively. Additionally for $0\nu\beta\beta$ decay the following limits at the 90% C.L. were obtained, $> 1.3 \cdot 10^{22}$ y for $^{48}$Ca, $> 9.2 \cdot 10^{21}$ y for $^{96}$Zr and $> 1.8 \cdot 10^{22}$ y for $^{150}$Nd. The $2\nu\beta\beta$ decay half-life values were precisely measured for all investigated isotopes.Comment: 12 pages, 4 figures, 5 tables; talk at conference on "Fundamental Interactions Physics" (ITEP, Moscow, November 23-27, 2009