Unexpected show up of incomplete fusion at low projectile energies

¹ INFN - Laboratori Nazionali di Legnaro, I-35020 Legnaro, Italy
² Acc. Lab., Department of Physics, A. M. University, Aligarh - 202 002, India
³ Physics Department, S. V. College, Aligarh - 202 001, India
⁴ NP-Group, Inter-University Accelerator Center, New Delhi - 110 067, India

^a e-mail: pushpendrapsingh@gmail.com, present address: GSI Helmholtz Centre for Heavy Ion Research GmbH, Planckstraße 1, D-64291 Darmstadt, Germany

Abstract

In this paper, some of the important findings of recent measurements performed to study incomplete fusion at low bombarding energies (i.e., E_lab ≈ 4-7 MeV/nucleon) in ¹²C, ¹⁶O+¹⁶⁹Tm systems are briefly summarized. The spin-distributions of xn, pxn, αxn/2αxn- channels have been measured to probe entirely different γ-emission patterns (and feeding intensity profiles) during the de-excitation of complete and incomplete fusion objects. Incomplete fusion strength function has been deduced (from the analysis of experimental excitation functions in context of equilibrated compound nucleus decay) to achieve information of onset and strength of incomplete fusion in terms of various entrance channel parameters. Presence of incomplete fusion at slightly above barrier energies has been confirmed by the measurement of linear momentum distribution of heavy recoils. Present results conclusively demonstrate, the existence of incomplete fusion at low bombarding energies, its strong dependence on entrance channel parameters, and the possibility to populate high spin states.