|
|
n_TOF Collaboration(Lederer, C. et al), Domingo-Pardo, C., Giubrone, G., & Tain, J. L. (2013). Neutron Capture Cross Section of Unstable Ni-63: Implications for Stellar Nucleosynthesis. Phys. Rev. Lett., 110(2), 022501–5pp.
Abstract: The Ni-63(n, gamma) cross section has been measured for the first time at the neutron time-of-flight facility n_TOF at CERN from thermal neutron energies up to 200 keV. In total, capture kernels of 12 (new) resonances were determined. Maxwellian averaged cross sections were calculated for thermal energies from kT = 5-100 keV with uncertainties around 20%. Stellar model calculations for a 25M(circle dot) star show that the new data have a significant effect on the s-process production of Cu-63, Ni-64, and Zn-64 in massive stars, allowing stronger constraints on the Cu yields from explosive nucleosynthesis in the subsequent supernova.
|
|
|
|
Salvatelli, V., Marchini, A., Lopez-Honorez, L., & Mena, O. (2013). New constraints on coupled dark energy from the Planck satellite experiment. Phys. Rev. D, 88(2), 023531–9pp.
Abstract: We present new constraints on coupled dark energy from the recent measurements of the cosmic microwave background anisotropies from the Planck satellite mission. We found that a coupled dark energy model is fully compatible with the Planck measurements, deriving a weak bound on the dark matter-dark energy coupling parameter xi = -0.49(-0.31)(+0.19) at 68% C.L. Moreover if Planck data are fitted to a coupled dark energy scenario, the constraint on the Hubble constant is relaxed to H-0 = 72.1(-2.3)(+3.2) km/s/Mpc, solving the tension with the Hubble Space Telescope (HST) value. We show that a combined PLANCK + HST analysis provides significant evidence for coupled dark energy finding a nonzero value for the coupling parameter xi, with -0.90 < xi < -0.22 at 95% C.L. We also consider the combined constraints from the Planck data plus the baryon acoustic oscillation measurements of the 6dF Galaxy Survey, the Sloan Digital Sky Survey and the Baron Oscillation Spectroscopic Survey.
|
|
|
|
Gottardo, A. et al, Gadea, A., & Algora, A. (2013). New μs isomers in the neutron-rich Hg-210 nucleus. Phys. Lett. B, 725(4-5), 292–296.
Abstract: Neutron-rich nuclei in the lead region, beyond N = 126, have been studied at the FRS-RISING setup at GSI, exploiting the fragmentation of a primary uranium beam. Two isomeric states have been identified in Hg-210: the 8(+) isomer expected from the seniority scheme in the vg(9/2) shell and a second one at low spin and low excitation energy. The decay strength of the 8(+) isomer confirms the need of effective three-body forces in the case of neutron-rich lead isotopes. The other unexpected low-lying isomer has been tentatively assigned as a 3(-) state, although this is in contrast with theoretical expectations.
|
|
|
|
Chachamis, G., Hentschinski, M., Madrigal Martinez, J. D., & Sabio Vera, A. (2013). Next-to-leading order corrections to the gluon-induced forward jet vertex from the high energy effective action. Phys. Rev. D, 87(7), 076009–11pp.
Abstract: We determine both real and virtual next-to-leading order corrections to the gluon-induced forward jet vertex from the high energy effective action proposed by Lipatov. For these calculations we employ the same regularization and subtraction formalism developed in our previous work on the quark-initiated vertex. We find agreement with previous results in the literature.
|
|
|
|
Jantzen, B., & Ruiz-Femenia, P. (2013). Next-to-next-to-leading order nonresonant corrections to threshold top-pair production from e(+)e(-) collisions: Endpoint-singular terms. Phys. Rev. D, 88(5), 054011–20pp.
Abstract: We analyze the subleading nonresonant contributions to the e(+)e(-) -> W(+)W(-)b (b) over bar cross section at energies near the top-antitop threshold. These correspond to next-to-next-to-leading-order (NNLO) corrections with respect to the leading-order resonant result. We show that these corrections produce 1/epsilon endpoint singularities which precisely cancel the finite-width divergences arising in the resonant production of the W(+)W(-)b (b) over bar final state from on-shell decays of the top and antitop quarks at the same order. We also provide analytic results for the (m(t)/Lambda)(2), (m(t)/Lambda) and (m(t)/Lambda)(0) log Lambda terms that dominate the expansion in powers of (Lambda/m(t)) of the complete set of NNLO nonresonant corrections, where Lambda is a cut imposed on the invariant masses of the bW pairs that is neither too tight nor too loose (m(t)Gamma(t) << Lambda(2) << m(t)(2)).
|
|
