Search results for "Functional analysis"
showing 10 items of 1059 documents
Relativistic Coulomb excitation of Kr 88
2016
International audience; To investigate the systematics of mixed-symmetry states in N=52 isotones, a relativistic Coulomb excitation experiment was performed during the PreSPEC campaign at the GSI Helmholtzzentrum für Schwerionenforschung to determine E2 transition strengths to 2+ states of the radioactive nucleus $^{88}$Kr. Absolute transition rates could be measured towards the first and third 2+ states. For the latter a mixed-symmetry character is suggested on the basis of the indication for a strong M1 transition to the fully symmetric 21+ state, extending the knowledge of the N=52 isotones below Z=40. A comparison with the proton-neutron interacting boson model and shell-model predictio…
Lifetime measurement of the first excited2+state in108Te
2011
The lifetime of the first excited 2(+) state in the neutron deficient nuclide (108)Te has been measured for the first time, using a combined recoil decay tagging and recoil distance Doppler shift t ...
The KK¯π decay of the f1(1285) and its nature as a K⁎K¯−cc molecule
2015
Abstract We investigate the decay of f 1 ( 1285 ) → π K K ¯ with the assumption that the f 1 ( 1285 ) is dynamically generated from the K ⁎ K ¯ − c c interaction. In addition to the tree level diagrams that proceed via f 1 ( 1285 ) → K ⁎ K ¯ − c c → π K K ¯ , we take into account also the final state interactions of K K ¯ → K K ¯ and π K → π K . The partial decay width and mass distributions of f 1 ( 1285 ) → π K K ¯ are evaluated. We get a value for the partial decay width which, within errors, is in fair agreement with the experimental result. The contribution from the tree level diagrams is dominant, but the final state interactions have effects in the mass distributions. The predicted m…
On the decay of theJπ= 11/2−,T1/2= 38.9 h isomer in133Ba: search for the E5 transition and verification of the EC branch
2010
International audience; This paper presents a search for the competing 11/2 − → 1/2 + E5 branch to the main 11/2 − → 3/2 + M4 transition from the T 1/2 = 39 h, J π = 11/2 − isomeric state in 133 Ba. An upper limit of 1.8 * 10 −5 could be established for the E5/M4 intensity ratio. In addition a long-standing controversy in the EC-decay of the same isomer was resolved: only one EC branch to the 11/2 + state in 133 Cs was observed. The shell-model structures of the involved states in 133 Ba and 133 Cs were studied with the microscopic quasiparticle-phonon model (MQPM). Good agreement with the decay rates B(λ) was obtained. In particular, the B(M4) value is well reproduced and further only one …
Properties of the 13/2+ isomeric decay in201Hg
1990
The isomeric decay of theT1/2=94 us isomeric state in201Hg was studied in beam via the reaction198Pt(α, n). Gamma-ray and conversion-electron spectra were recorded. From the conversion coefficients, the multipolarities of the two depopulating transitions were determined to beM 2 + 10%E 3 andE 2, respectively. These assignments give the depopulating transitions to be 13/2+ → 9/2− and 9/2− → 5/2−, and these thus substantiate the previous suggestion that the isomeric state hasJπ=13/2+. For the 13/2+ → 9/2−M 2 transition a detailed study ofE 3 andM 4 admixed amplitudes was done. The microscopic properties of the 13/2+ and 9/2− states are discussed, and a comparison to the corresponding ones in1…
Microscopic description ofα+40Caquasimolecular resonances
2001
A multistep microscopic approach describing the dynamics of quasimolecular resonances is applied to the $\ensuremath{\alpha}{+}^{40}\mathrm{Ca}$ system. The lowest collective two-particle eigenmodes are used as building blocks of the four-particle states. The pair states are built on mean-field single-particle orbitals including also sharp resonances in continuum. The structure of ${}^{44}\mathrm{Ti}$ is analyzed and strong high-lying $\ensuremath{\alpha}$-like resonances are found in good agreement with the experimentally observed quasimolecular spectrum. The resonances turn out to be very collective and contain mostly proton-neutron pairs where the lowest proton single-particle resonance,…
K-isomeric state in even-even100Sr
1995
A t1/2=85 ns isomer has been identified at 1619 keV in100Sr. The halflife is attributed to a ΔK=4 hindered decay. The configuration is proposed to be built on the [411]3/2 and the [532]5/2 neutron quasiparticle orbitals.
The β2p decay mechanism of Ar
2000
We have measured the beta-decay of Ar-31 with a high granularity setup sensitive to multiparticle decay branches. Two-proton emission is observed from the isobaric analog state in Cl-31 to the four lowest states in P-29 and furthermore from a large number of states fed in Gamow-Teller transitions. The mechanism of two-proton emission is studied via energy and angular correlations between the two protons. In all cases the mechanism is found to be sequential yielding information about states in S-30 up to 8 MeV excitation energy. Improved data on the beta-delayed one-proton branches together with the two-proton data provide precise information about the beta-strength distribution up to 15 MeV…
Linear confinement in momentum space: singularity-free bound-state equations
2014
Relativistic equations of Bethe-Salpeter type for hadron structure are most conveniently formulated in momentum space. The presence of confining interactions causes complications because the corresponding kernels are singular. This occurs not only in the relativistic case but also in the nonrelativistic Schr\"odinger equation where this problem can be studied more easily. For the linear confining interaction the singularity reduces to one of Cauchy principal value form. Although this singularity is integrable, it still makes accurate numerical solutions difficult. We show that this principal value singularity can be eliminated by means of a subtraction method. The resulting equation is much…
On the chiral covariant approach to ρρ scattering
2017
We examine in detail a recent work (D.~G\"ulmez, U.-G.~Mei\ss ner and J.~A.~Oller, Eur. Phys. J. C 77:460 (2017)), where improvements to make $\rho\rho$ scattering relativistically covariant are made. The paper has the remarkable conclusion that the $J=2$ state disappears with a potential which is much more attractive than for $J=0$, where a bound state is found. We trace this abnormal conclusion to the fact that an "on-shell" factorization of the potential is done in a region where this potential is singular and develops a large discontinuous and unphysical imaginary part. A method is developed, evaluating the loops with full $\rho$ propagators, and we show that they do not develop singula…