Nuclear Physics A 780 (2006) 206–221 Some observations related to intermittency and multifractality in 28 Si and 12 C-nucleus collisions at 4.5 A GeV Shafiq Ahmad ∗ , M. Ayaz Ahmad Physics Department, Aligarh Muslim University, Aligarh 202002, India Received 16 June 2006; received in revised form 1 September 2006; accepted 19 September 2006 Available online 19 October 2006 Abstract An attempt is made to study the existence of dynamical fluctuations of relativistic particles using the methods of modified multifractal moments, G q , and scaled factorial moments, F q , in terms of new scaled variable X(η) suggested by Bialas and Gazdzicki. For this purpose analyses of experimental and UrQMD data involving interactions of 28 Si and 12 C nuclei at 4.5 A GeV/c with nuclear emulsion are used. The variation of ln〈G q 〉 and ln〈F q 〉 with ln M in pseudorapidity (η) phase space reveals power law behaviour. The values of slopes, τ q and φ q determined from the analyses of G q and F q moments are discussed. The generalized fractal dimensions, D q , determined from the above methods are found to decrease with the order of the moments, q , indicating multifractality in multiparticle production. It is also observed that the spectral function f (α q ) for heavier projectile is much broader than for lighter beam due to larger number of participating nucleons present in heavier projectile.  2006 Elsevier B.V. All rights reserved. PACS: 25.70.Pq; 13.85.Hd Keywords: NUCLEAR REACTIONS H, C, N, O, Ag, Br( 12 C, X), ( 28 Si, X), E at 4.5 GeV per nucleon; measured fragments multiplicity, pseudorapidity, density distributions; deduced multifractal moments, scaled factorial moments, spectral functions. * Corresponding author. E-mail address: sahmad2004amu@yahoo.co.in (S. Ahmad). 0375-9474/$ – see front matter  2006 Elsevier B.V. All rights reserved. doi:10.1016/j.nuclphysa.2006.09.009