123803933
Nuclear charge radii of heavy and superheavy nuclei from the experimental alpha-decay energies and half-lives
The radius of a nucleus is one of the important quantities in nuclear physics. Although there are many researches on ground-state properties of superheavy nuclei, researches on charge radii of superheavy nuclei are rare. In this article, nuclear root-mean-square (rms) charge radii of heavy and superheavy nuclei are extracted from the experimental alpha-decay data. alpha-decay calculations are performed within the generalized density-dependent cluster model, where alpha-decay half-lives are evaluated using quasibound state wave functions. The charge distribution of daughter nuclei is determined in the double-folding model to reproduce the experimental alpha-decay half-lives. The rms charge radius is then calculated using the resulting charge distribution. In addition, a simple formula is also proposed to calculate nuclear charge radii with the experimental alpha-decay energies and half-lives. The formula is directly derived from the Wentzel-Kramers-Brillouin barrier penetration probability with some approximations. The two different methods show good agreement with the experimental data for even-even nuclei, and the deduced results are consistent with other theoretical models. Moreover, nuclear radii of heavy and superheavy nuclei with Z = 98-116 are extracted from the alpha-decay data, for which alpha decay is a unique tool to probe nuclear sizes at present. This is the first result on nuclear charge radii of superheavy nuclei based on the experimental alpha-decay data. DOI: 10.1103/PhysRevC.87.024310
54500815
Rotation and alignment of high-j orbitals in transfermium nuclei
The structure of nuclei with Z ~ 100 is investigated systematically by the Cranked Shell Model (CSM) with pairing correlations treated by a Particle-Number Conserving (PNC) method. In the PNC method, the particle number is conserved and the Pauli blocking effects are taken into account exactly. By fitting the experimental single-particle spectra in these nuclei, a new set of Nilsson parameters ( κ and µ ) is proposed. The experimental kinematic moments of inertia and the band-head energies are reproduced quite well by the PNC-CSM calculations. The band crossing, the effects of high- j intruder orbitals and deformation are discussed in detail.
121943751
Theoretical study of nuclear charge densities with elastic electron scattering
The calculated cross sections for elastic Coulomb electron scattering from the phase-shift analysis method and the eikonal approximation are compared. It is shown that the phase-shift analysis method can reproduce the experimental data very well for both light and heavy nuclei. Then the phase-shift analysis is used to investigate elastic electron scattering along the O and S isotopic chains, where the charge densities are obtained from relativistic mean-field theory. Results show that the minima of the differential cross section shift inward and upward with the increase of the neutron number.
121588345
Coupled-channels study of fine structure in the {alpha} decay of well deformed nuclei
We formulate a theoretical model for the {alpha} decay of well-deformed even-even nuclei based on the coupled-channel Schroedinger equation. The {alpha}-decay half-lives and fine structures observed in {alpha} decay are well described by the five-channel microscopic calculations. Since the branching ratios to high-spin states are hard to understand in the traditional {alpha}-decay theories, this success could be important to interpret future observations of heavier nuclei. It is also found that the {alpha} transition to high-spin states is a powerful tool to probe the energy spectrum and deformation of daughter nuclei.
120766429
Systematic calculations of the ground state properties of superheavy nuclei
We investigate the ground state properties of the nuclei with proton number $Z=94\char21{}110$ within the framework of deformed relativistic mean-field (RMF) theory. A systematic comparison between calculated binding energies and experimental data is made. The calculated binding energies are in good agreement with experimental ones. The reliability of the RMF model for superheavy nuclei has been tested by this comparison. The experimental data of alpha-decay energies and half-lives are reasonably reproduced by calculations. Calculated results further show that a prolate deformation is important for the ground state of these nuclei. The properties of some unknown nuclei are predicted and these are useful for future experimental researches of superheavy nuclei.
119699060
β-decay half-lives including first-forbidden contributions for neutron-rich Zn isotopes in the extended QRPA with neutron-proton pairing
The β decays of neutron-rich Zn isotopes are investigated within the extended quasiparticle random-phase approximation, where neutron-neutron, proton-proton, and neutron-proton pairing correlations are considered in the similar manner. The Bruckner G-matrix obtained with the charge-dependent Bonn nucleon-nucleon force is used for the residual particle-particle and particle-hole interactions in addition to the pairing interactions. Contributions from both allowed Gamow-Teller and first-forbidden transitions are considered, and β-decay half-lives together with β-delayed neutron emission probabilities are calculated. The calculated results are found to agree well with the available experimental data.
209521249
Search for long-lived, heavy particles in final states with a muon and multi-track displaced vertex in proton-proton collisions at √s=7 TeV with the ATLAS detector
Many extensions of the Standard Model posit the existence of heavy particles with long lifetimes. In this Letter, results are presented of a search for events containing one or more such particles, which decay at a significant distance from their production point, using a final state containing charged hadrons and an associated muon. This analysis uses a data sample of proton-proton collisions at root s = 7 TeV corresponding to an integrated luminosity of 4.4 fb(-1) collected in 2011 by the ATLAS detector operating at the Large Hadron Collider. Results are interpreted in the context of R-parity violating supersymmetric scenarios. No events in the signal region are observed and limits are set on the production cross section for pair production of supersymmetric particles, multiplied by the square of the branching fraction for a neutralino to decay to charged hadrons and a muon, based on the scenario where both of the produced supersymmetric particles give rise to neutralinos that decay in this way. However, since the search strategy is based on triggering on and reconstructing the decay products of individual long-lived particles, irrespective of the rest of the event, these limits can easily be reinterpreted in scenarios with different numbers of long-lived particles per event. The limits are presented as a function of neutralino lifetime, and for a range of squark and neutralino masses.
5839313
Measurement of D± and D0 production in deep inelastic scattering using a lifetime tag at HERA
AbstractThe production of D±- and D0-mesons has been measured with the ZEUS detector at HERA using an integrated luminosity of 133.6 pb−1. The measurements cover the kinematic range 5<Q2<1000 GeV2, 0.02<y<0.7, 1.5<pTD<15 GeV and |ηD|<1.6. Combinatorial background to the D-meson signals is reduced by using the ZEUS microvertex detector to reconstruct displaced secondary vertices. Production cross sections are compared with the predictions of next-to-leading-order QCD, which is found to describe the data well. Measurements are extrapolated to the full kinematic phase space in order to obtain the open-charm contribution, 
$F_{2}^{c\bar{c}}$
, to the proton structure function, F2.
16324397
An NLO QCD analysis of inclusive cross-section and jet-production data from the ZEUS experiment
The ZEUS inclusive differential cross-section data from HERA, for charged and neutral current processes taken with e(+) and e(-) beams, together with differential cross-section data on inclusive jet production in e+ p scattering and dijet production in gamma p scattering, have been used in a new NLO QCD analysis to extract the parton distribution functions of the proton. The input of jet-production data constrains the gluon and allows an accurate extraction of alpha(s)( M-Z) at NLO;alpha(s)( M-Z) = 0.1183 +/- 0.0028( exp.) +/- 0.0008( model).An additional uncertainty from the choice of scales is estimated as +/- 0.005. This is the first extraction of as( M-Z) from HERA data alone.
119163803
Inclusive-jet photoproduction at HERA and determination of alpha(s)
Abstract Inclusive-jet cross sections have been measured in the reaction e p → e + jet + X for photon virtuality Q 2 1 GeV 2 and γp centre-of-mass energies in the region 142 W γ p 293 GeV with the ZEUS detector at HERA using an integrated luminosity of 300 pb − 1 . Jets were identified using the k T , anti- k T or SIScone jet algorithms in the laboratory frame. Single-differential cross sections are presented as functions of the jet transverse energy, E T jet , and pseudorapidity, η jet , for jets with E T jet > 17 GeV and − 1 η jet 2.5 . In addition, measurements of double-differential inclusive-jet cross sections are presented as functions of E T jet in different regions of η jet . Next-to-leading-order QCD calculations give a good description of the measurements, except for jets with low E T jet and high η jet . The influence of non-perturbative effects not related to hadronisation was studied. Measurements of the ratios of cross sections using different jet algorithms are also presented; the measured ratios are well described by calculations including up to O ( α s 2 ) terms. Values of α s ( M Z ) were extracted from the measurements and the energy-scale dependence of the coupling was determined. The value of α s ( M Z ) extracted from the measurements based on the k T jet algorithm is α s ( M Z ) = 0.1206 − 0.0022 + 0.0023 ( exp . ) − 0.0035 + 0.0042 ( th . ) ; the results from the anti- k T and SIScone algorithms are compatible with this value and have a similar precision.
119232865
Diffractive photoproduction of dijets in ep collisions at HERA
Diffractive photoproduction of dijets was measured with the ZEUS detector at the ep collider HERA using an integrated luminosity of 77.2 pb-1. The measurements were made in the kinematic range Q2 < 1 GeV2, 0.20<y<0.85 and xIP<0.025, where Q2 is the photon virtuality, y is the inelasticity and xIP is the fraction of the proton momentum taken by the diffractive exchange. The two jets with the highest transverse energy, ETjet, were required to satisfy ETjet>7.5 and 6.5 GeV, respectively, and to lie in the pseudorapidity range -1.5<ηjet<1.5. Differential cross sections were compared to perturbative QCD calculations using available parameterisations of diffractive parton distributions of the proton. 