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from di ra tive s attering and leading baryon produ tion D. Reyna for the H1 and ZEUS ollaborations DESY, 22603 Hamburg (Email: reyna mail.desy.de) Abstra t We present preliminary results from both the H1 and ZEUS experiments at HERA for four di erent hadroni nal state analyses in the area of leading baryon and di ra tive pro esses. These measurements are used to aid our understanding of the intera tions through olor singlet ex hange. 1. Introdu tion Sin e the early days of hadron-hadron s attering, a signi ant part of the ross se tion has been seen to ome from soft, olor-singlet ex hange. A phenomenologi al des ription was reated in whi h the ross se tion ould be des ribed in terms of two asymptoti Regge traje tories known as the Reggeon (IR) and the Pomeron (IP). When HERA rst turned on, it was quite striking to learn that approximately 10% of the total ross se tion was made up again of a olor singlet ex hange pro ess. This implied that HERA ould provide an environment for areful study of this pro ess. In this paper, four di erent pro esses are presented whi h have been re ently analyzed at the H1 and ZEUS experiments in an attempt to better understand the nature of these olor-singlet ex hanges. 2. Di-Jets Events with Leading Neutrons This rst measurement deals mainly in the kinemati al region in whi h the reggeon traje tory is dominant. To test our expe tation that the Regge phenomenology implies a single ex hanged parti le, the tagged di-jet nal state o ers a good environment. A tagged neutron provides a lean forward signature of the proton system, while the di-jet provides a hard s ale in the nal state. The 1995 data from ZEUS[1℄ support the expe tation of fa torization in su h a pro ess, by looking at the ratio of events with a tagged neutron to those without (Fig. 1). This ratio remains onstant, independent of the transverse energy of the jets. In addition, the neutron energy spe trum is independent of the ex hanged photon momentum. ZEUS 1995 Preliminary 0 0.02 0.04 0.06 0.08 0.1 0.12 6 8 10 12 14 16 18 20 22 24