Search for solar axions by Primakoff effect in NaI crystals

The results of a search for possible signal due to Primakoff coherent conve rsion of solar axions into photons in NaI(Tl) are presented. The experiment has been carried out at the Gran Sasso National Laboratory of INFN; the us ed statistics is 53437 kg day. The presently most stringent experimental li mit on g(a gamma gamma) from this process is obtained: g(a gamma gamma) < 1 .7 x 10(-9) GeV-1 (90% C.L.). In particular, the axion mass window m(a) gre ater than or similar to 0.03 eV, not accessible by other direct methods, is explored and KSVZ axions with mass larger than 4.6 eV are excluded at 90% C.L. (C) 2001 Elsevier Science B.V. All rights reserved.