Search results for "Fysiikka"

ISOL-method in studies of medium-heavy Z ~ N nuclei

2003

Single-particle states and parity doublets in odd-Z 221Ac and 225Pa from α-decay spectroscopy

2022

Low-lying states in the odd-Z isotopes 22189Ac132 and 22591Pa134 have been studied using α-particle and αγ-coincidence spectroscopy in the 225Pa→221Ac→217Fr decay chain. Ground-state spin and parity assignments of Iπ = 5/2− are proposed for both 221Ac and 225Pa, with the odd proton occupying the Ω = 5/2 orbital of the quadrupole-octupole deformed shell model in both nuclei. In 221Ac, excited states in the bands based on the Ω = 5/2 and Ω = 3/2 orbitals have been identified, including proposed parity-doublet states. The results suggest that reflection-asymmetric deformation of the ground state persists in the odd-A members of the isotope chains down to N = 132 for Ac and N = 134 for Pa, befo…

¹¹³Cd:n ja ¹¹⁵In:n perustilan beetahajoaminen MQPM-mallin avulla laskettuna

2005

Microscopic quasiparticle-phonon model in the study of the beta decay of Cd-115

2013

This master’s thesis concerns the use of the microscopic quasiparticle-phonon model in the study of the beta minus decay of Cd-115. The first part of this text concentrates on the theoretical description of nearly spherical open-shell odd-A nuclei by using the microscopic quasiparticle-phonon model. The treatment of the subject is far from exhaustive but all the necessary relations needed in the practical application of the formalism are provided in the text. The second part provides the theory that is needed for the study of beta minus decay. In addition to the general theory of forbidden beta minus decay, also the greatly simplified case of allowed transitions are discussed. Again rather …

Effective axial-vector coupling in beta decay of mass region A = 100 - 134 isotopes

2014

Tutkielmassa tarkastellaan massa-alueen A = 100 - 134 ytimien käyttäytymistä beetahajoamisessa käyttäen QRPA-formalismia. Tavoitteena oli tutkia heikon vuorovaikutuksen efektiivisen aksiaalivektorikytkentävakion gA käyttäytymistä massaluvun A funktiona. Tarkasteltavaksi valittiin kaikki mahdolliset ydintripletit, joissa on "keskellä" kaksoispariton (Z pariton, N pariton) ydin, jolla on 1+-perustila ja kokeellisesti havaittuja beetasiirtymiä kahden kaksoisparillisen naapuri-isobaarinsa kanssa. gA:n arvot kiinnitettiin laskemalla jokaisen kaksoisparittoman ytimen Gamow-Teller-matriisielementtien geometrinen keskiarvo ja sovittamalla se kokeelliseen dataan. Tuloksena saatiin lineaarinen malli …

K∗(892)0 and φ(1020) production in p-Pb collisions at √sNN = 8.16 TeV

2023

The production of K∗(892)0 and ϕ(1020)resonances has been measured in p-Pb collisions at √sNN = 8.16 TeV using the ALICE detector. Resonances are reconstructed via their hadronic decay channels in the rapidity interval −0.5 8 GeV/c), the RpPb values of all hadrons are consistent with unity within uncertainties. The RpPb of K∗(892)0and ϕ(1020)at √sNN = 8.16 and 5.02 TeV show no significant energy dependence. peerReviewed

Observation of flow angle and flow magnitude fluctuations in Pb-Pb collisions at √sNN = 5.02 TeV at the CERN Large Hadron Collider

2023

This Letter reports on the first measurements of transverse momentum dependent flow angle Ψn and flow magnitude vn fluctuations determined using new four-particle correlators. The measurements are performed for various centralities in Pb–Pb collisions at a center-of-mass energy per nucleon pair of √SNN = 5.02 TeV with ALICE at the CERN Large Hadron Collider. Both flow angle and flow magnitude fluctuations are observed in the presented centrality ranges and are strongest in the most central collisions and for a transverse momentum pT>2GeV/c. Comparison with theoretical models, including iEBE-VISHNU, MUSIC, and AMPT, show that the measurements exhibit unique sensitivities to the initial state…

Experimental evidence for transverse wobbling bands in 136Nd

2022

The nature of two high-spin bands in 136Nd built on the two-quasiparticle configuration πh211/2, predicted by the triaxial projected shell model as good candidates of transverse wobbling bands, are investigated experimentally. The mixing ratio of one ΔI=1 transition connecting the one-phonon and the zero-phonon wobbling bands is established from a high-statistics JuroGam II γ-ray spectroscopy experiment by using the combined angular correlation and linear polarization method. The resulting wobbling excitation energy and ratios of reduced electromagnetic transition probabilities are in good agreement with results of a new particle-rotor model which rigidly couples the total angular momentum …

High-precision mass measurement of 31S with the double Penning trap JYFLTRAP improves the mass value for 32Cl

2010

The science case of the FRS Ion Catcher for FAIR Phase-0

2019

The FRS Ion Catcher at GSI enables precision experiments with thermalized projectile and fission fragments. At the same time it serves as a test facility for the Low-Energy Branch of the Super-FRS at FAIR. The FRS Ion Catcher has been commissioned and its performance has been characterized in five experiments with 238U and 124Xe projectile and fission fragments produced at energies in the range from 300 to 1000 MeV/u. High and almost element-independent efficiencies for the thermalization of short-lived nuclides produced at relativistic energies have been obtained. High-accuracy mass measurements of more than 30 projectile and fission fragments have been performed with a multiple-reflection…