119964168
Examining the energy dependence of symmetry potential in asymmetric nuclear matter
By using the Hugenholtz-Van Hove (HVH) theorem, the symmetry potential in asymmetric nuclear matter is found to be closely related to symmetry energy E-sym(rho) and its density slope L(rho). The energy dependence of symmetry potential at saturation density rho(0) is extracted by using recent constraints on both E-sym (rho(0)) and L(rho(0)) from different methods not only in nuclear structures and reactions but also in astrophysics. The extracted symmetry potentials from different methods are found to be generally consistent with each other. By averaging all extracted symmetry potentials, an energy-dependent form of symmetry potential at the saturation density is obtained, which could be useful to calibrate the single-particle potentials in mean-field models of structures and transport models of reactions. (C) 2013 Elsevier B.V. All rights reserved.
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.
126298012
New Geiger-Nuttall law for alpha decay of heavy nuclei
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.
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.
117483857
Search for quark contact interactions in dijet angular distributions in pp collisions at s=7 TeV measured with the ATLAS detector
Dijet angular distributions from the first LHC pp collisions at center-of-mass energy sqrt(s) = 7 TeV have been measured with the ATLAS detector. The dataset used for this analysis represents an integrated luminosity of 3.1 pb-1. Dijet $\chi$ distributions and centrality ratios have been measured up to dijet masses of 2.8 TeV, and found to be in good agreement with Standard Model predictions. Analysis of the $\chi$ distributions excludes quark contact interactions with a compositeness scale $\Lambda$ below 3.4 TeV, at 95% confidence level, significantly exceeding previous limits.
118924957
Measurement of neutral current cross sections at high Bjorken-x with the ZEUS detector at HERA
A new method is employed to measure the neutral current cross section up to Bjorken-x values of one with the ZEUS detector at HERA using an integrated luminosity of 65.1 pb-1 for e+p collisions and 16.7 pb-1 for e-p collisions at $\sqrt{s}=318\,\mathrm{GeV}$ and 38.6 pb-1 for e+p collisions at $\sqrt{s}=300\,\mathrm{GeV}$. Cross sections have been extracted for Q2≥648 GeV2 and are compared to predictions using different parton density functions. For the highest x bins, the data have a tendency to lie above the expectations using recent parton density function parametrizations.
17317939
Inclusive jet cross sections in the Breit frame in neutral current deep inelastic scattering at HERA and determination of alpha s
Inclusive jet differential cross sections have been measured in neutral current deep inelastic e(+)p scattering for boson virtualities Q(2) > 125 GeV2. The data were taken using the ZEUS detector at HERA and correspond to an integrated luminosity of 38.6 pb(-1). Jets were identified in the Breit frame using the longitudinally invariant k(T) cluster algorithm. Measurements of differential inclusive jet cross sections a-re presented as functions of jet transverse energy (E-T.jet(B)), jet pseudorapidity and Q(2), for jets with E-T.jet(B) > 8 GeV. Next-to-leading-order QCD calculations agree well with the measurements both at high Q(2) and high E-T.jet(B). The value of alpha(s) (M-Z), determined from an analysis of dsigma/dQ(2) for Q(2) > GeV2, is alphas (M-Z) = 0.1212 +/- 0.0017(stat.)(-0.0031)(+0.0023)(syst.)(-0.0027)(+0.0028)(th.). (C) 2002 Elsevier Science B.V. All rights reserved.
122100793
Search for the $X_b$ and other hidden-beauty states in the $\pi^+ \pi^- \Upsilon(1 \rm S)$ channel at ATLAS
This Letter presents a search for a hidden-beauty counterpart of the X(3872) in the mass ranges of 10.05–10.31 GeV and 10.40–11.00 GeV, in the channel Xb→π+π−ϒ(1S)(→μ+μ−) , using 16.2 fb −1 of s=8 TeV pp collision data collected by the ATLAS detector at the LHC. No evidence for new narrow states is found, and upper limits are set on the product of the Xb cross section and branching fraction, relative to those of the ϒ(2S) , at the 95% confidence level using the CLS approach. These limits range from 0.8% to 4.0%, depending on mass. For masses above 10.1 GeV, the expected upper limits from this analysis are the most restrictive to date. Searches for production of the ϒ(13DJ) , ϒ(10860) , and ϒ(11020) states also reveal no significant signals.
118293635
Measurement of inelastic J/PSI production in deep inelastic scattering at HERA
The inelastic production of J/psi mesons in ep collisions has been studied with the ZEUS detector at HERA using an integrated luminosity of 109 pb(-1). The J/psi mesons were identified using the decay channel J/psi -> mu(+)mu(-). The measurements were performed in the kinematic range 2 < Q(2) < 80 GeV2, 50 < W < 250 GeV, 0.2 < z < 0.9 and -1.6 < Y-lab < 1.3, where Q(2) is the virtuality of the exchanged photon, W is the photon-proton centre-of-mass energy, z is the fraction of the photon energy carried by the J/psi meson in the proton rest frame and Ylab is the rapidity of the J/psi in the laboratory frame. The measured cross sections are compared to theoretical predictions within the non-relativistic QCD framework including colour-singlet and colour-octet contributions, as well as to predictions based on the k(T)-factorisation approach. Calculations of the colour-singlet process generally agree with the data, whereas inclusion of colour-octet terms spoils this agreement.