(3He,t) reaction on the double β decay nucleus 48Ca and the importance of nuclear matrix elements

E.-W. Grewe, D. Frekers, S. Rakers, T. Adachi, C. Baumer, N.T. Botha, H. Dohmann, H. Fujita, Y. Fujita, K. Hatanaka, K. Nakanishi, A. Negret, R. Neveling, Lucia Popescu, Y. Sakemi, Y. Shimbara, Y. Shimizu, F.D. Smit, Y. Tameshinge, A. TamiiJ. Thies, P. von Brentano, M. Yosoi, R.G.T. Zegers, Jan Heyse

    Research outputpeer-review


    (3He, t) measurements on the double β-decay (ββ) nucleus 48Ca have been performed at RCNP (Osaka, Japan) to determine Gamow-Teller (GT−) transitions to the nucleus 48Sc, which represents the intermediate nucleus in the second-order perturbative description of the ββ decay. At a bombarding energy of E3He = 420 MeV an excitation energy resolution of 40 keV was achieved. The measurements were performed at two angle positions of the GR Spectrometer: 0◦ and 2.5◦. The results of both settings were combined to achieve angular distributions, by which the character of single transitions could be determined. To characterize the different multipoles, theoretical angular distributions for states with J π = 1+, 2+, 2−, and 3+ were calculated using the distorted-wave Born approximation Code DW81. The GT− strength was extracted up to Ex = 7MeV and combined with corresponding GT+ strength deduced from the 48Ti(d, 2He)48Sc data to calculate the low-energy part of the ββ-decay matrix element for the 48Ca 2νββ decay. We show that after applying trivial momentum corrections to the (3He, t) spectrum, the two reaction probes, (p, n) and (3He, t) reveal a spectral response to an impressively high degree of similarity in the region of low momentum transfer.
    Original languageEnglish
    Pages (from-to)54307-54307
    JournalPhysical Review C
    Issue number5
    StatePublished - 8 Nov 2007

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