Large asymmetry in the strongest β-transition for A=9

7 pages, 1 table, 4 figures.-- PACS nrs.: 23.40.Hc; 21.10.Hw; 27.20.+n.-- Printed version published Dec 4, 2003.A new measurement of the β-decay of Li-9 has clarified the feeding to the highest accessible states in Be-9. It is found that the β-decay mainly populates the 11.8 MeV state, whose spin is determined as 5/2(-). The extracted B-GT value of 5.3(0.9) is a factor 4.4(1.0) larger than that of the mirror transition from C-9. A theoretical explanation of such a pronounced β-decay asymmetry is presently lacking.One of us (Y.P.) thanks the Spanish Ministery of Science and Technology for the 4-year grant assigned to the project AEN1999-1046-C02-01. The work was supported by the European Union Fifth Framework Programme “Improving Human Potential, Access to Research Infrastructure”.Peer reviewe