Study of azimuthal correlations in the target fragmentation region in p, d, He, C+C, Ta and C+Ne, Cu collisions at momenta of 4.2, 4.5 and 10 A GeV/c

L. Chkhaidze; G. Chlachidze; T. Djobava; A. Galoyan; L. Kharkhelauri; R. Togoo; V. Uzhinsky

doi:10.1140/epja/i2019-12674-9

EPJ

Study of azimuthal correlations in the target fragmentation region in p, d, He, C+C, Ta and C+Ne, Cu collisions at momenta of 4.2, 4.5 and 10 A GeV/c

L. Chkhaidze¹, G. Chlachidze², T. Djobava¹, A. Galoyan³^*, L. Kharkhelauri¹, R. Togoo⁴ and V. Uzhinsky⁵

¹ High Energy Physics Institute, I. Javakhishvili Tbilisi State University, Tbilisi, Georgia
² Fermi National Accelerator Laboratory, 60510, Batavia, Illinois, USA
³ Veksler and Baldin Laboratory of High Energy Physics, Joint Institute for Nuclear Research, Dubna, Russia
⁴ Institute of Physics and Technology of the Mongolian Acad. Sci., Ulan Bator, Mongolia
⁵ Laboratory of Information Technologies, Joint Institute for Nuclear Research, Dubna, Russia

Received: 12 August 2018
Accepted: 4 December 2018
Published online: 23 January 2019

Abstract

Azimuthal correlations between the same type of particles (protons or pions) in the target fragmentation region was studied in d, He, C+C, Ta (4.2A GeV/c, C+Ne, Cu (4.5A GeV/c) and p+C, Ta (10 GeV/c) interactions. The data were obtained from the SKM-200-GIBS streamer chamber and from the Propane Bubble Chamber (PBL-500) systems utilized at JINR. Study of multiparticle azimuthal correlations offers unique information about space-time evolution of the interactions. Azimuthal correlations were investigated by using correlation function $C(\Delta\phi) = \mathrm{d} N/\mathrm{d} (\Delta\phi)$ , where $\Delta\phi$ represents the angle between the sums of transverse momenta vectors for particles emitted in the forward and backward hemispheres. For protons “back-to-back” (“negative”) azimuthal correlations were observed in the above-mentioned interactions. The absolute values of the correlation coefficient $\vert\xi\vert$ --the slope parameter of $C(\Delta\phi)$ , strongly depend on the mass number of the target ( $A_{T}$ ) nuclei in the nucleon-nucleus and nucleus-nucleus collisions. Namely, $\vert\xi\vert$ decreases with increase of $ A_T$

in p+C and p+Ta collisions, while $\vert\xi\vert$ initially decreases from d+C to C+Ne and then almost does not change with increase of $ A_P$

in (d+He)Ta, C+Cu and C+Ta collisions. For pions “back-to-back” correlations were obtained for light targets (C, Ne), and “side-by-side” (“positive”) correlations for heavy targets (Cu, Ta). The $\vert\xi\vert$ insignificantly changes with increase of the momenta per nucleon and almost does not change with increase of $ A_P$

and

. Models used for description of the data, the Ultra relativistic Quantum Molecular Dynamic (UrQMD) and Quark-Gluon String Model (QGSM), satisfactorily describe the obtained experimental results.

15th European Conference on Atoms Molecules and Photons (ECAMP)
June 30 to July 4, 2025
Innsbruck, Austria

EPJ

Study of azimuthal correlations in the target fragmentation region in p, d, He, C+C, Ta and C+Ne, Cu collisions at momenta of 4.2, 4.5 and 10 A GeV/c

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