Nuclear Charge Radius of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mmultiscripts><mml:mrow><mml:mi>Al</mml:mi></mml:mrow><mml:mprescripts/><mml:none/><mml:mrow><mml:mn>26</mml:mn><mml:mi>m</mml:mi></mml:mrow></mml:mmultiscripts></mml:mrow></mml:math> and Its Implication for <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">V</mml:mi></mml:mrow><mml:mrow><mml:mi>u</mml:mi><mml:mi>d</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:math> in the Quark Mixing Matrix
P. Plattner, Edward J. Wood, L. Al Ayoubi, O. Beliuskina, M. L. Bissell, K. Blaum, P. Campbell, B. Cheal, R. P. de Groote, C. S. Devlin, T. Eronen, Livio Filippin, R. F. García Ruíz, Z. W. Ge, S. Geldhof, W. Gins, Michel Godefroid, H. Heylen, M. Hukkanen, Phillip Imgram, A. Jaries, A. Jokinen, A. Kanellakopoulos, A. Kankainen, S. Kaufmann, Kristian König, Á. Koszorús, S. Kujanpää, S. Lechner, S. Malbrunot-Ettenauer, Patrick Müller, R. Mathieson, I. D. Moore, W. Nörtershäuser, D. A. Nesterenko, R. Neugart, G. Neyens, A. Ortiz-Cortes, H. Penttilä, I. Pohjalainen, A. Raggio, M. Reponen, S. Rinta-Antila, L. V. Rodríguez, J. Romero, R. Sánchez, F. Sommer, M. Stryjczyk, V. Virtanen, Liang Xie, Z. Y. Xu, X. F. Yang, D. T. Yordanov
Abstract
Collinear laser spectroscopy was performed on the isomer of the aluminium isotope ^{26m}Al. The measured isotope shift to ^{27}Al in the 3s^{2}3p ^{2}P_{3/2}^{○}→3s^{2}4s ^{2}S_{1/2} atomic transition enabled the first experimental determination of the nuclear charge radius of ^{26m}Al, resulting in R_{c}=3.130(15) fm. This differs by 4.5 standard deviations from the extrapolated value used to calculate the isospin-symmetry breaking corrections in the superallowed β decay of ^{26m}Al. Its corrected Ft value, important for the estimation of V_{ud} in the Cabibbo-Kobayashi-Maskawa matrix, is thus shifted by 1 standard deviation to 3071.4(1.0) s.