Coherent dissociation of relativistic 9 C nuclei

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MENTARY PARTICLES AND FIELDS Experiment

Coherent Dissociation of Relativistic 9 C Nuclei ´ 2), P. I. Zarubin1)* , D. O. Krivenkov1), D. A. Artemenkov1) , V. Bradnova1), S. Vokal 1) 1) 1) I. G. Zarubina , N. V. Kondratieva , A. I. Malakhov , A. A. Moiseenko3) , G. I. Orlova4), N. G. Peresadko4) , N. G. Polukhina4), P. A. Rukoyatkin1), V. V. Rusakova1), V. R. Sarkisyan3), R. Stanoeva1), M. Haiduc5), and S. P. Kharlamov4) Received February 10, 2010; in final form, June 2, 2010

Abstract—Results on the coherent dissociation of relativistic 9 C nuclei in a nuclear track emulsion are described. These results include the charge topology and kinematical features of final states. Events of 9 C → 33 Нe coherent dissociation are identified. DOI: 10.1134/S106377881012015X

INTRODUCTION The coherent dissociation of relativistic nuclei on heavy target nuclei is induced in electromagnetic and nuclear diffractive interactions not accompanied by the production of target fragments and mesons. Events of this type, which are referred to as “white” stars, are observed in a nuclear track emulsion with a unique reliability [1–3]. They constitute several percent of the total number of inelastic interactions. The use of nuclear track photoemulsions ensures the completeness of observation of relativistic fragments with an excellent angular resolution. The assumption of the equality of the momenta per nucleon (or velocities) of the relativistic nucleus under study and its fragments may be a seminal hypothesis in a kinematical analysis. The angular resolution and, hence, the spatial resolution, which underlies it and which has a record value of 0.5 μm in the method of nuclear track emulsions, are of crucial importance here. In the dissociation of light nuclei, statistical distributions over various configurations of relativistic fragments clearly show their cluster features as a consequence of the fact that the excitation transfer is 1)

Joint Institute for Nuclear Research, Dubna, Moscow oblast, 141980 Russia. 2) ˇ arik, ´ ˇ University of P.J. Saf Jesenna´ 5, SK041 54 Kosice, Slovak Republic. 3) Yerevan Physics Institute, ul. Brat’ev Alikhanian 2, Yerevan, 375036 Republic of Armenia. 4) Lebedev Institute of Physics, Russian Academy of Sciences, Leninskii pr. 53, Moscow, 117924 Russia. 5) Institute for Space Sciences, P.O.Box MG-23, Ro 077125, Bucharest-Magurele, Romania. * E-mail: [email protected]

minimal [4–9]. Investigation of neutron-deficient nuclei is particularly advantageous since the interpretation of respective experimental results is more certain. In a nuclear track emulsion irradiated with beams from the nuclotron of the Joint Institute for Nuclear Research (JINR, Dubna), the Becquerel Collaboration [10] has already studied the cluster structure of dissociation of the 7 Be [8] and 8 B [9] nuclei. This created preconditions for proceeding to study the next isotope at the drip line, 9 C. It can be hoped that the pattern already obtained for the 8 Be and 7 В nuclei must be reproduced, with an addition of one or two protons, in the coher