117752223
Decays of the Y-97 isomers to the single neutron nucleus Zr-97
The decays of the 9/2(+) and of the three-quasiparticle high spin isomer in Y-97 have been investigated following on-line mass separation with the ion-guide technique. Spins and parities for several of the lowest-lying levels in the daughter nucleus Zr-97 are revised and configurations are proposed. In particular, the 2264 keV level is identified as the h(11/2) single-neutron level. The population of a cascade on top of the h(11/2) level provides evidence for Gamow-Teller beta decay of the high-spin Y-97 isomer. Levels and transition rates are qualitatively well reproduced by regarding Zr-97 as a single-neutron nucleus with respect to the doubly closed Zr-96 core.
1861803
Gamma-ray spectroscopy at the limits: first observation of rotational bands in 255Lr.
The rotational band structure of 255Lr has been investigated using advanced in-beam gamma-ray spectroscopic techniques. To date, 255Lr is the heaviest nucleus to be studied in this manner. One rotational band has been unambiguously observed and strong evidence for a second rotational structure was found. The structures are tentatively assigned to be based on the 1/2-[521] and 7/2-[514] Nilsson states, consistent with assignments from recently obtained alpha decay data. The experimental rotational band dynamic moment of inertia is used to test self-consistent mean-field calculations using the Skyrme SLy4 interaction and a density-dependent pairing force.
115613705
Identification of the Kpi=8- rotational band in 138Gd
120743809
Spectroscopy of Ho-144 using recoil-isomer tagging
Excited states in the proton-unbound odd-odd nucleus {sup 144}Ho have been populated using the {sup 92}Mo({sup 54}Fe,pn){sup 144}Ho reaction and studied using the recoil-isomer-tagging technique. The alignment properties and signature splitting of the rotational band above the I{sup p}i=(8{sup +}){sup 144m}Ho isomer have been analyzed and the isomer confirmed to have a pih{sub 11/2} x nuh{sub 11/2} two-quasiparticle configuration. The configuration-constrained blocking method has been used to calculate the shapes of the ground and isomeric states, which are both predicted to have triaxial nuclear shapes with |gamma|approx =24 deg.
117103201
alpha decay of Re159 and proton emission from Ta155
121158687
High-K four-quasiparticle states in Gd-138
States above the known K(pi) = 8(-) 6 mu s isomer in (138)Gd have been populated with the (106)Cd((36)Ar,2p2n) reaction at a beam energy of 180 MeV at the University of Jyvaskyla, Finland. The recoil-isomer tagging technique was utilized to correlate delayed gamma-ray decays, detected in the GREAT focal plane spectrometer, with prompt decays measured in the JUROGAM II spectrometer at the target position. The lifetime of the K(pi) = 8(-) isomeric state has been remeasured as 6.2(2) mu s. Two high-lying strongly coupled bands have been established with K(pi) >= 12(-). Potential-energy surface calculations, in conjunction with g factor measurements, reveal that they are built upon four-quasiparticle structures comprising two-quasineutron plus two-quasiproton configurations. The short half-life or lack of hindrance for the decays from these four-quasiparticle band-head states is reasoned to be a consequence of increased triaxial deformation and mixing due to the high density of states relative to the lower two-quasiparticle 6-mu s isomeric state.
7991709
Measurement of inelastic, single- and double-diffraction cross sections in proton–proton collisions at the LHC with ALICE
Measurements of cross sections of inelastic and diffractive processes in proton–proton collisions at LHC energies were carried out with the ALICE detector. The fractions of diffractive processes in inelastic collisions were determined from a study of gaps in charged particle pseudorapidity distributions: for single diffraction (diffractive mass MX<200 GeV/c2) $\sigma_{\mathrm{SD}}/\sigma_{\mathrm {INEL}} = 0.21 \pm 0.03, 0.20^{+0.07}_{-0.08}$, and $0.20^{+0.04}_{-0.07}$, respectively at centre-of-mass energies $\sqrt{s} = 0.9, 2.76\mbox{, and }7~\mbox{TeV}$; for double diffraction (for a pseudorapidity gap Δη>3) σDD/σINEL=0.11±0.03,0.12±0.05, and $0.12^{+0.05}_{-0.04}$, respectively at $\sqrt{s} = 0.9, 2.76\mbox{, and }7~\mbox{TeV}$. To measure the inelastic cross section, beam properties were determined with van der Meer scans, and, using a simulation of diffraction adjusted to data, the following values were obtained: $\sigma_{\mathrm{INEL}} = 62.8^{+2.4}_{-4.0} (\mathrm{model}) \pm1.2 (\mathrm{lumi})$ mb at $\sqrt{s} = 2.76\ \mbox{TeV}$ and $73.2^{+2.0}_{-4.6} (\mathrm{model}) \pm2.6 (\mathrm{lumi})~\mbox{mb}$ at $\sqrt{s} = 7\ \mbox{TeV}$. The single- and double-diffractive cross sections were calculated combining relative rates of diffraction with inelastic cross sections. The results are compared to previous measurements at proton–antiproton and proton–proton colliders at lower energies, to measurements by other experiments at the LHC, and to theoretical models.
1982882
Evidence from d+Au measurements for final-state suppression of high-p(T) hadrons in Au+Au collisions at RHIC.
We report measurements of single-particle inclusive spectra and two-particle azimuthal distributions of charged hadrons at high transverse momentum (high p(T)) in minimum bias and central d+Au collisions at sqrt[s(NN)]=200 GeV. The inclusive yield is enhanced in d+Au collisions relative to binary-scaled p+p collisions, while the two-particle azimuthal distributions are very similar to those observed in p+p collisions. These results demonstrate that the strong suppression of the inclusive yield and back-to-back correlations at high p(T) previously observed in central Au+Au collisions are due to final-state interactions with the dense medium generated in such collisions.
208859933
Incident Energy Dependence of pt Correlations at RHIC
We present results for two-particle transverse momentum correlations, ({Delta}p{sub t,i}{Delta}p{sub t,j}), as a function of event centrality for Au+Au collisions at {radical}s{sub NN} = 20, 62, 130, and 200 GeV at the Relativistic Heavy Ion Collider. We observe correlations decreasing with centrality that are similar at all four incident energies. The correlations multiplied by the multiplicity density increase with incident energy and the centrality dependence may show evidence of processes such as thermalization, jet production, or the saturation of transverse flow. The square root of the correlations divided by the event-wise average transverse momentum per event shows little or no beam energy dependence and generally agrees with previous measurements at the Super Proton Synchrotron.
123238985
Testing models of hadron production with strange hadrons in the intermediate pT region using the STAR detector
We report on the transverse momentum dependence of strangeness production measured with the STAR detector. Identified particle spectra are used to provide a test of models of hadron production in the intermediate transverse momentum region, 2 < pT < 6 GeV/c. Further insight into hadron production is obtained from the nuclear modification factor, Rcp, in Au+Au collisions, which shows that there is a different pT dependence of hadron suppression in central collisions for baryons and mesons, consistent with quark coalescence. Evidence for a similar baryon–meson difference is also found in d+Au collisions.
28575636
Charged-particle multiplicity measurement in proton–proton collisions at $\sqrt{s}=0.9$ and 2.36 TeV with ALICE at LHC
Charged-particle production was studied in proton–proton collisions collected at the LHC with the ALICE detector at centre-of-mass energies 0.9 TeV and 2.36 TeV in the pseudorapidity range |η|<1.4. In the central region (|η|<0.5), at 0.9 TeV, we measure charged-particle pseudorapidity density $\mathrm{d}N_{\mathrm{ch}}/\mathrm{d}\eta=3.02\pm 0.01(\mathit{stat.})^{+0.08}_{-0.05}(\mathit{syst.})$ for inelastic interactions, and $\mathrm{d}N_{\mathrm{ch}}/\mathrm{d}\eta=3.58\pm0.01(\mathit{stat.})^{+0.12}_{-0.12}(\mathit{syst.})$ for non-single-diffractive interactions. At 2.36 TeV, we find $\mathrm{d}N_{\mathrm{ch}}/\mathrm{d}\eta=3.77\pm0.01(\mathit{stat.})^{+0.25}_{-0.12}(\mathit{syst.})$ for inelastic, and $\mathrm{d}N_{\mathrm{ch}}/\mathrm{d}\eta=4.43\pm0.01(\mathit{stat.})^{+0.17}_{-0.12}(\mathit{syst.})$ for non-single-diffractive collisions. The relative increase in charged-particle multiplicity from the lower to higher energy is $24.7\%\pm0.5\%(\mathit{stat.})^{+5.7}_{-2.8}\%(\mathit{syst.})$ for inelastic and $23.7\%\pm0.5\%(\mathit{stat.})^{+4.6}_{-1.1}\%(\mathit{syst.})$ for non-single-diffractive interactions. This increase is consistent with that reported by the CMS collaboration for non-single-diffractive events and larger than that found by a number of commonly used models. The multiplicity distribution was measured in different pseudorapidity intervals and studied in terms of KNO variables at both energies. The results are compared to proton–antiproton data and to model predictions.