123815311
Systematic study of charge form factors of elastic electron-nucleus scattering with the relativistic eikonal approximation
We systematically investigate the elastic electron scattering on both stable and unstable nuclei with the relativistic eikonal approximation, where the charge density distributions of nuclei are from the self-consistent relativistic mean field model. Calculations show that the relativistic eikonal approximation can reproduce the experimental data of electron scattering on nuclei ranging from the light region, such as {sup 12}C, to the heavy region, such as {sup 208}Pb. This is the systematic test of the relativistic eikonal approximation for elastic electron scattering for both light and heavy nuclei. With this method, further studies are made of the variation of charge form factors along isotopic chains and the sensitivity of charge form factors to the changes of charge distribution. For isotopic chains with Z = 20 and 28, we find that the charge form factors vary significantly with neutron number. The charge form factors shift outward and downward when the target nucleus moves from the neutron-rich region to the proton-rich region along the isotopic chain. The significant shift shows that the charge form factor is very sensitive to a change of neutron number. If the isotopic shifts of the charge form factor are measured on the next-generation electron-nucleus collider (at RIKEN and more » GSI), the charge size and charge distribution can be determined for unstable nuclei. The calculations will provide a reference for future experiments. « less
126298012
New Geiger-Nuttall law for alpha decay of heavy nuclei
122795101
Relativistic eikonal approaches to parity violating electron-nucleus scattering
The Coulomb electron scattering on even-even nuclei and the magnetic electron scattering on odd-$A$ nuclei have been investigated in the relativistic eikonal approximation and in the plane wave Born approximation, respectively. In this article, we generalize the relativistic eikonal approximation to the parity violating electron scattering on even-even nuclei. The parity violating asymmetries at electron energy of 850 MeV are calculated for three typical cases: Ca isotopes, $N=50$ isotones, and $N=Z$ doubly magic nuclei. In calculations the proton and neutron densities are obtained from the relativistic mean-field theory. The parity violating asymmetries are analyzed by comparing both the form factors and the densities of neutrons and protons. It is found that the parity violating asymmetries are sensitive to the differences between neutron and proton densities. Our results provide useful references for the parity violating electron-nucleus scattering experiments in the future.
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.
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.
209869998
Observation of the decay psi(2S) ---> K*(892)anti-K + c.c.
209521027
Measurement of upsilon production in 7 TeV pp collisions at ATLAS
Using 1.8  fb-1 of pp collisions at a center-of-mass energy of 7 TeV recorded by the ATLAS detector at the Large Hadron Collider, we present measurements of the production cross sections of Υ(1S,2S,3S) mesons. Υ mesons are reconstructed using the dimuon decay mode. Total production cross sections for pT<70  GeV and in the rapidity interval |yΥ|<2.25 are measured to be, 8.01±0.02±0.36±0.31  nb, 2.05±0.01±0.12±0.08  nb, and 0.92±0.01±0.07±0.04  nb, respectively, with uncertainties separated into statistical, systematic, and luminosity measurement effects. In addition, differential cross section times dimuon branching fractions for Υ(1S), Υ(2S), and Υ(3S) as a function of Υ transverse momentum pT and rapidity are presented. These cross sections are obtained assuming unpolarized production. If the production polarization is fully transverse or longitudinal with no azimuthal dependence in the helicity frame, the cross section may vary by approximately ±20%. If a nontrivial azimuthal dependence is considered, integrated cross sections may be significantly enhanced by a factor of 2 or more. We compare our results to several theoretical models of Υ meson production, finding that none provide an accurate description of our data over the full range of Υ transverse momenta accessible with this data set.
53982386
Measurement of charged current deep inelastic scattering cross sections with a longitudinally polarised electron beam at HERA
Measurements of the cross sections for charged current deep inelastic scattering in e−p collisions with longitudinally polarised electron beams are presented. The measurements are based on a data sample with an integrated luminosity of 175 pb−1 collected with the ZEUS detector at HERA at a centre-of-mass energy of 318 GeV. The total cross section is given for positively and negatively polarised electron beams. The differential cross-sections dσ/dQ2, dσ/dx and dσ/dy are presented for Q2>200 GeV2. The double-differential cross-section d2σ/dxdQ2 is presented in the kinematic range 280<Q2<30 000 GeV2 and 0.015<x<0.65. The measured cross sections are compared with the predictions of the Standard Model.
119852910
Measurement of the mass difference between top and anti-top quarks in pp collisions at √s = 7 TeV using the ATLAS detector
A measurement of the mass difference between top and anti-top quarks is presented. In a 4.7 fb(-1) data sample of proton-proton collisions at root s = 7 TeV recorded with the ATLAS detector at the ...
119256577
Measurement of high-Q2 neutral current deep inelastic e−p scattering cross sections with a longitudinally polarised electron beam at HERA
AbstractMeasurements of the neutral current cross sections for deep inelastic scattering in e−p collisions at HERA with a longitudinally polarised electron beam are presented. The single-differential cross-sections dσ/dQ2, dσ/dx and dσ/dy and the double-differential cross sections in Q2 and x are measured in the kinematic region y<0.9 and Q2>185 GeV2 for both positively and negatively polarised electron beams and for each polarisation state separately. The measurements are based on an integrated luminosity of 169.9 pb−1 taken with the ZEUS detector in 2005 and 2006 at a centre-of-mass energy of 318 GeV. The structure functions 
$x\tilde{F_{3}}$ 
and xF3γZ are determined by combining the e−p results presented in this paper with previously measured e+p neutral current data. The asymmetry parameter A− is used to demonstrate the parity violating effects of electroweak interactions at large spacelike photon virtuality. The measurements agree well with the predictions of the Standard Model.