BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//CERN//INDICO//EN
BEGIN:VEVENT
SUMMARY:PROBING OF STRONG INTERACTIONS AND HADRON MATTER IN HADRON AND HEA
 VY ION COLLISIONS
DTSTART;VALUE=DATE-TIME:20201005T164500Z
DTEND;VALUE=DATE-TIME:20201005T170000Z
DTSTAMP;VALUE=DATE-TIME:20261014T230134Z
UID:indico-contribution-2338@cern.ch
DESCRIPTION:Speakers: Mikhail Barabanov (JINR)\nThe spectroscopy of charmo
 nium-like mesons with masses above the 2_mD open charm threshold has been 
 full of surprises and remains poorly understood [1]. The currently most co
 mpelling theoretical descriptions of the mysterious XYZ mesons attribute t
 hem to hybrid structure with a tightly bound cc\\bar diquark [2] or cq(cq)
 \\bar tetraquark core [3 - 5] that strongly couples to S-wave DD\\bar mole
 cular like structures. In this picture\, the production of a XYZ states in
  high energy hadron collisions and its decays into light hadron plus charm
 onum final states proceed via the core component of the meson\, while deca
 ys to pairs of open-charmed mesons proceed via the DD\\bar component.\nThe
 se ideas have been applied with some success to the XYZ states [2]\, where
  a detailed calculation finds a cc\\bar core component that is only above 
 5% of the time with the DD\\bar component (mostly D0D0\\bar) accounting fo
 r the rest. In this picture these states are compose of three rather dispa
 rate components: a small charmonium-like cc\\bar core with r_rms  9 fm spa
 tial extent. Here µ+(µ0) and B+(B0) denote the reduced mass for the D+D-
  (D0D0\\bar) system and the relevant binding energy |m_D + m_D - M_X(3872)
 | (B+ = 8.2 MeV\, B0  150 fm [8].\nThe experiments with proton-proton and 
 proton-nuclei collisions with √S_pN up to 26 Gev and luminosity up to 10
 ^32 cm^-2s^-1 planned at NICA may be well suited to test this picture for 
 the X(3872) and other XYZ mesons. In near threshold production experiments
  in the √S_pN ≈ 8 GeV energy range\, XYZ mesons can be produced with t
 ypical kinetic energies of a few hundred MeV (i.e. with γβ ≈ 0.3). In 
 the case of X(3872)\, its decay length will be greater than 50 fm while th
 e distance scale for the cc\\bar → D0D*0 transition would be 2 ~ 3 fm. S
 ince the survival probability of an r_rms ~ 9 fm “molecular” inside nu
 clear matter should be very small\, XYZ meson production on a nuclear targ
 et with r_rms ~ 5 fm or more (A ~ 60 or larger) should be strongly quenche
 d. Thus\, if the hybrid picture is correct\, the atomic number de-pendence
  of XYZ production at fixed √S_pN should have a dramatically different b
 ehavior than that of the ψ'\, which is long lived compact charmonium stat
 e.\nThe current experimental status of XYZ mesons together with hidden cha
 rm tetraquark can-didates and present simulations what we might expect fro
 m A-dependence of XYZ mesons in proton-proton and proton-nuclei collisions
  are summarized.\nReferences\n[1] S. Olsen\, Front. Phys. 10 101401 (2015)
 \n[2] S. Takeuchi\, K. Shimizu\, M. Takizawa\, Progr. Theor. Exp. Phys. 20
 15\, 079203 (2015)\n[3] A. Esposito\, A. Pilloni\, A.D. Poloza\, arXiv:160
 3.07667[hep-ph]\n[4] M.Y.Barabanov\, A.S.Vodopyanov\, S.L.Olsen\, A.I.Zinc
 henko\, Phys. Atom. Nuc. 79\, 1\, 126 (2016)\n[5] M.Yu. Barabanov\, A.S. V
 odopyanov\, S.L. Olsen\, Phys. Scripta 166 014019 (2015)\n[6] N. Isgur\, P
 hys. Rev. D 32\, 189 (1985)\n[7] K. Olive et al. (PDG)\, Chin. Phys. C 38\
 , 090001 (2014)\n[8] The width of X(3872) is experimentally constrained to
  be Г X(3872) \n\nhttps://indico.particle.mephi.ru/event/35/contributions
 /2338/
LOCATION:Discord Poster Server
URL:https://indico.particle.mephi.ru/event/35/contributions/2338/
END:VEVENT
END:VCALENDAR