Search results for "Branch"
showing 10 items of 1278 documents
New interpretation of shape coexistence in99Zr
1997
Levels in ${}^{99}\mathrm{Zr}$ populated by $\ensuremath{\beta}$ decay of on-line mass separated ${}^{99}$Y have been studied by $\ensuremath{\gamma}$-ray spectroscopic methods, including $\ensuremath{\gamma}$-$\ensuremath{\gamma}$ coincidences recorded with an array of ten Ge detectors and level-lifetime measurements. The formerly reported strongly collective character of the 53-keV transition turns out to be questionable. This implies a revision of the experimental evidence for shape coexistence in ${}^{99}\mathrm{Zr}.$ Transition rates and $\ensuremath{\gamma}$-ray branching ratios make a new level at 679 keV with ${t}_{1/2}=9$ ns another candidate for a deformed state.
Isomeric and ground-state properties of78171Pt,76167Os, and74163W
2010
Decay paths, half-lives, and excitation energies of the i(13/2) bandheads of the neutron-deficient nuclei Pt-171, Os-167, and W-163 have been established for the first time. Gamma-ray transitions, ...
Measurements of the branching fractions forJ/ψandψ′→ΛΛ¯π0andΛΛ¯η
2013
We report on a study of the isospin-violating and isospin-conserving decays of the J/psi and psi' charmonium state to Lambda(Lambda) over bar pi(0) and Lambda(Lambda) over bar eta, respectively. The data are based on 225 million J/psi and 106 million psi' events that were collected with the BESIII detector. The most accurate measurement of the branching fraction of the isospin-violating process J/psi -> Lambda(Lambda) over bar pi(0) is obtained, and the isospin-conserving processes J/psi -> Lambda(Lambda) over bar eta and psi' -> Lambda(Lambda) over bar eta are observed for the first time. The branching fractions are measured to be B(J/psi -> Lambda(Lambda) over bar pi(0)) = (3.78 +/- 0.27(…
Observation of the decay KLO→ e+e−ep+e−
1991
Abstract Two events with the characteristic of the decay K L O → e + e − e − have been observed with a negligible expected background from which a branching ratio of (4±3)×10 −8 is derived. This result is consistent with values estimated from theoretical models based on the double internal conventional of the decay K L O → γγ .
Measurement ofη′→π+π−e+e−andη′→π+π−μ+μ−
2013
Based on a sample of 225.3 million $J/\ensuremath{\psi}$ events accumulated with the BESIII detector at the BEPCII, the decays of ${\ensuremath{\eta}}^{\ensuremath{'}}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}{l}^{+}{l}^{\ensuremath{-}}$ are studied via $J/\ensuremath{\psi}\ensuremath{\rightarrow}\ensuremath{\gamma}{\ensuremath{\eta}}^{\ensuremath{'}}$. A clear ${\ensuremath{\eta}}^{\ensuremath{'}}$ signal is observed in the ${\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}{e}^{+}{e}^{\ensuremath{-}}$ mass spectrum, and the branching fraction is measured to be $\mathcal{B}({\ensuremath{\eta}}^{\ensuremath{'}}\ensuremath{\rightarrow}{\ensuremat…
Beta decay of 108Mo and of neighbouring even Mo-isotopes
1995
Abstract A combination of the proton-induced fission of 238 U and the on-line mass separation based on the ion-guide technique has been applied in the study of neutron-rich Mo-isotopes. The decays of 106,108 Mo have been studied by using gamma-, beta-, X-ray and conversion-electron spectroscopy. The decay scheme of 106 Mo has been revised and a beta-decay half-life of 8.73(12) s has been measured for this nucleus. A beta-decay half-life of 1.09(2) s and a decay energy of 5120(40) keV have been measured for 108 Mo. The decay scheme of 108 Mo has been constructed and altogether 29 new transitions have been placed in the decay scheme. The beta-decay strengths of 102,104,106,108 Mo have been de…
Is the single-state dominance realized in double-β-decay transitions?
1998
In the single-state-dominance hypothesis (SSDH) the decay rate of the two-neutrino double-\ensuremath{\beta} decay to the final ground state is solely determined by virtual single-\ensuremath{\beta}-decay transitions via the ${1}^{+}$ ground state of the intermediate nucleus. A very important consequence the SSDH will be that some of nonaccelerator measurements of double-\ensuremath{\beta}-decay observables could be circumvented by single-\ensuremath{\beta}-decay measurements. To assess the validity of the SSDH, we have carried out a theoretical analysis of all double-\ensuremath{\beta}-decay transitions where the spin-parity of the ground-state of the intermediate nucleus is ${1}^{+}$. The…
Characterizing the atomic mass surface beyond the proton drip line viaα-decay measurements of theπs1/2ground state of165Re and theπh11/2isomer in161Ta
2012
The α-decay chains originating from the πs1/2 and πh11/2 states in 173Au have been investigated following fusion-evaporation reactions. Four generations of α radioactivities have been correlated with 173Aum leading to a measurement of the α decay of 161Tam. It has been found that the known α decay of 161Ta, which was previously associated with the decay of the ground state, is in fact the decay of an isomeric state. This work also reports on the first observation of prompt γ rays feeding the ground state of 173Au. This prompt γ radiation was used to aid the study of the α-decay chain originating from the πs1/2 state in 173Au. Three generations of α decays have been correlated with this stat…
Chromomagnetic dipole-operator corrections inB¯→XsγatO(β0αs2)
2010
We calculate the fermionic corrections to the photon-energy spectrum of $\overline{B}\ensuremath{\rightarrow}{X}_{s}\ensuremath{\gamma}$ which arise from the self-interference of the chromomagnetic dipole operator ${Q}_{8}$ at next-to-next-to-leading order by applying naive non-Abelianization. The resulting $\mathcal{O}({\ensuremath{\beta}}_{0}{\ensuremath{\alpha}}_{s}^{2})$ correction to the $\overline{B}\ensuremath{\rightarrow}{X}_{s}\ensuremath{\gamma}$ branching ratio amounts to a relative shift of $+0.12%$ ($+0.27%$) for a photon-energy cut of 1.6 GeV (1.0 GeV). We also comment on the potential size of resummation and nonperturbative effects related to ${Q}_{8}$.
Three-body hadronic molecules
2010
In this talk, I discuss our recent studies of three-hadron systems and the resonances found therein. The studies consist of solving Faddeev equations with the input two body interactions obtained from the chiral Lagrangians. The systems which we study are either made of two mesons and a baryon or of three mesons. The motivation for these studies comes from the data on many baryon resonances, especially the ones with Jπ = 1/2+, which show a large branching ratio to the two meson-one baryon decay channels. In addition to this, several new studies at BES, BELLE, BABAR etc., claim the existence of new meson resonances which seem to couple strongly to three-meson systems, where mostly two out of…