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SUMMARY:Double spin correlations  in the reaction dd→ pnpn  and  elastic
  proton-nucleon  scattering at large angles
DTSTART;VALUE=DATE-TIME:20241025T084500Z
DTEND;VALUE=DATE-TIME:20241025T090000Z
DTSTAMP;VALUE=DATE-TIME:20260305T211012Z
UID:indico-contribution-4307@cern.ch
DESCRIPTION:Speakers: Yuriy Uzikov (Joiny Institute for Nuclear Researches
 )\nElastic pp scattering  at the invariant mass of the pp-system $\\sqrt{s
 _{pp}}= 3 - 5$\nGeV  and large c.m.s. angles ($\\theta_{cm}=90^\\circ$)  d
 emonstrates  a\nvery large double-spin correlation [1]. These kinematical 
 region corresponds to very high momentum trasfer |t|\n where quark countin
 g rules are valid and color transparency is expected to be  observed. On t
 he other hand\,\n these energies correspond to the thresholds for strangen
 ess (~ 3 GeV)  and charm  (~5 GeV) production in pp collisions\, respectiv
 ely. As was shown in [2]\, the observed strong correlations (cross-section
  ratio of 4 : 1 for parallel and antiparallel spins of colliding protons) 
 are compatible with the assumption of the formation of uudss̄uud and uudc
 c̄uud octoquark resonances in the s channel. Moreover\, on the basis of t
 his assumption\, the authors of Ref. [2] also explained qualitatively an u
 nusual behavior of the color transparency in reactions of the A(p\, 2p)B t
 ype and oscillations in the differential cross section\n dσ/dt for elasti
 c pp scattering in the region of manifestation of quark counting rules. Ho
 wever\, the last two effects have a different explanation within the nucle
 ar-filtering model [3]. In this connection one should note that hard dynam
 ics in elastic pp and pn-scattering may be markedly different\, because  t
 he pn-scattering includes the isoscalar channel in addition to the isovect
 or one. In view of this\, it is of importance to study the doubly polarize
 d channel of elastic pn scattering in the same energy range of 3-5 GeV. In
  principle\, this may be done at the SPD in the dd collisions [4]. We stud
 ied [5] double spin correlation of the reaction  dd-> pnpn within the impu
 lse (double pole) approximation and found that at zero relative momenta of
  nucleons in both deuterons\, when the deuteron S-wave dominates\, the tra
 nsversal and longitudinal- correlation coincides with the similar double-s
 pin correlation in pp or pn- elastic large angle scattering. Effects of re
 scatterings and the D-wave contribution are under consideration.\n\n The r
 esearch is supported under  the Scientific Program JINR – Republic of Ka
 zakstan.\n\n[1] D. G. Crabb\, R. C. Fernow\, P. H. Hansen\, et al. Phys. R
 ev. Lett. 41\, 1257 (1978).\n\n[2] S. J. Brodsky and G. de Teramond\, Phys
 . Rev. Lett. 60\, 1924 (1988).\n\n[3] J. P. Ralston and B. Pire\, Phys. Re
 v. Lett. 49\, 1605 (1982).\n\n[4] V. Abramov et al. Phys. Part. Nucl. 52\,
  1044 (2021).\n\n[5] Yu. Uzikov\, A. Temerbayev\, Phys. Part. Nucl. 55\, N
 4\, 895 (2024).\n\nhttps://indico.particle.mephi.ru/event/436/contribution
 s/4307/
LOCATION: Moskvorechye 2
URL:https://indico.particle.mephi.ru/event/436/contributions/4307/
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