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IDS Collaboration(Lica, R. et al), & Morales, A. I. (2018). Evolution of deformation in neutron-rich Ba isotopes up to A=150. Phys. Rev. C, 97(2), 024305–12pp.
Abstract: The occurrence of octupolar shapes in the Ba isotopic chain was recently established experimentally up to N = 90. To further extend the systematics, the evolution of shapes in the most neutron-rich members of the Z = 56 isotopic chain accessible at present, Ba-148,Ba-150, has been studied via beta decay at the ISOLDE Decay Station. This paper reports on the first measurement of the positive-and negative-parity low-spin excited states of 150Ba and presents an extension of the beta-decay scheme of Cs-148. Employing the fast timing technique, half-lives for the 2(1)(+) level in both nuclei have been determined, resulting in T-1/2 = 1.51(1) ns for Ba-148 and T-1/2 = 3.4(2) ns for Ba-150. The systematics of low-spin states, together with the experimental determination of the B(E2 : 2(+) -> 0(+)) transition probabilities, indicate an increasing collectivity in Ba148-150, towards prolate deformed shapes. The experimental data are compared to symmetry conserving configuration mixing (SCCM) calculations, confirming an evolution of increasingly quadrupole deformed shapes with a definite octupolar character.
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T2K Collaboration(Abe, K. et al), Cervera-Villanueva, A., Izmaylov, A., Novella, P., Sorel, M., & Stamoulis, P. (2018). Measurement of the single pi(0) production rate in neutral current neutrino interactions on water. Phys. Rev. D, 97(3), 032002–13pp.
Abstract: The single pi(0) production rate in neutral current neutrino interactions on water in a neutrino beam with a peak neutrino energy of 0.6 GeV has been measured using the empty set, one of the subdetectors of the T2K near detector. The production rate was measured for data taking periods when the Pempty setD contained water (2.64 x 10(20) protons-on-target) and also periods without water (3.49 x 10(20) protons-on-target). A measurement of the neutral current single pi(0) production rate on water is made using appropriate subtraction of the production rate with water in from the rate with water out of the target region. The subtraction analysis yields 106 +/- 41 +/- 69 signal events where the uncertainties are statistical (stat.) and systematic (sys.) respectively. This is consistent with the prediction of 157 events from the nominal simulation. The measured to expected ratio is 0.68 +/- 0.26(stat) +/- 0.44(sys) +/- 0.12(flux). The nominal simulation uses a flux integrated cross section of 7.63 x 10(-39) cm(2) per nucleon with an average neutrino interaction energy of 1.3 GeV.
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