Correlations between Cumulative Particles and Heavy Flavor Production in Relativistic Nucleus-Nucleus Collisions

1. G.Feofilov, V.Kovalenko, V.Vechernin (St.Petersburg State University,RF) Reported by Grigory Feofilov28 June 2017 QFTHEP-2017, Yaroslavl This work is supported bytheRussianScienceFoundation, GRANT 16-12-10176 Future studies of correlations between cumulative particles and heavy flavor production in relativistic nucleus-nucleus collisions

2. Layout • Introduction. • Heavy-Flavour, cumulative effect and some theoretical approaches • What is new proposed for the fixed-target HEP experiment? • Study of correlations between cumulative particles and heavy flavour (strangeness and charm) production in widely separated rapidity intervals • First simulations in UrQMD of correlations between cumulative particles and charged particle yield in p+C collisions at 400 GeV (lab) • Summary and plans

3. Why heavy flavours? In pp collisions at high energies: to test pQCDcalculations ( see [1,2] etc.])based on a factorisationapproach, where the cross-sections are calculated as a convolution of three terms: • the parton distribution functions of the incoming protons; (2) the partonic hard scattering rate, and (3) a fragmentation function of the charm quark into a given charm hadron. In pPbcollisions at high energies: • to test “the cold nuclear matter” effects In Pb-Pb collisions • -- Study of early stages of heavy-ion collisions • Probe for study thermalizationof QGP __ C C [1] M. Cacciari, M. Greco and P. Nason, JHEP 9805 (1998) 007; M. Cacciari, S. Frixione and P. Nason, JHEP 0103 (2001) 006. -----NLO calculations---HF-pT spectra [2] M. Cacciari, P. Nason and Ramona Vogt, QCD Predictions for Charm and Bottom Production at RHIC, https://arxiv.org/pdf/hep-ph/0502203.

4. Why heavy flavours?Matter induced changes in the yield of quarkonia • 1986Charmonim suppression in AA collisions • (H.Satz and T.Matsui, Phys.Lett.B178(1986)416): • All charmonia are produced before QGP formation • Suppression takes place in QGP • Some charmonia may survive beyond Tc 2013 -- Mechanisms contributing to matter induced changes in the yield of quarkonia: Color screening (upper left); ionization by thermal gluons (lower left); and recombination (right) (Berndt Mu ̈ller,, arXiv:1309.7616)

5. Why heavy flavours? Some recent review of existing experimental data on charm and beauty yields in hadron collisions – see e.g. report by Shingo Sakai: “Heavy-flavourproductions in the relativistic heavy ion collisions in LHC “, EPJ Web of Conferences 137, 07020 (2017) DOI: 10.1051/epjconf/201713707020 XIIth Quark Confinement & the Hadron Spectrum __ C C • In this work we propose a study of rare type of heavy-flavourproduction that might be induced by the cumulative particle formation mechanism

6. Why cumulative particles? • Study of early stages of heavy-ion collisions • Study such rare process as formationof the “drops of the cold QGP” –multi quark configurations (or fluctons) prepared beforethe collision

7. Kinematics of cumulative production in pA for fixed target Cumulative processes - productionofparticleswithenergiesoutsidethekinematiclimitoffreenucleoncollisionsatrelativisticenergies. Kinematic boundary Masses Energy conservation Boundary conditions in the rest frame of the nucleus and at p>>m for x=1,2,3... nucleons merged to flucton: .

8. Kinematics of cumulative production in pA for fixed target /example for cumulative pions Kinematic boundaries for x=1, 2, 3 . Angles in backward hemisphere ~ 90-180 Ideal to measure in the fixed-target experiments

9. Cumulative effect • The 1st experimental observations [1,2]: • Collisions p+d (Ep=660 MeV), fixed target : • Observation of backwardprotons • Collisions p+A (Ep=675 MeV), Li, Be, C, and O • fixed target: • Observation of high yields of deutrons • The 1st explanation: the hypothesis of • nuclear fluctons (D. I. Blokhintsev [2]) • The production of high-energy fragments • from the collision of fast nucleons with nuclei • can be treated as the result of the collision • of the nucleon with fluctuations of nuclear matter. • SIZE OF FLUCTUATION << NUCLEON SIZEReferences • G. A. Leksinetal., ZhETF 32, 445 (1957). • L.S. Azhgirejetal., ZhETF 33, 1185 (1957). • D. I. Blokhintsev, ZhETF 33, 1295 (1957). Flucton .

10. Theoretical approachesto mechanisms of cumulative particle production • Fireball • G.M. Zinovjev M.I. Gorenstein. In: Phys. Lett. B 67 (1977), p. 100. • V.P.Shelest M.I. Gorenstein G.M. Zinovjev. In: Yad. Fiz. 26 (1977), p. 788. • Yu.M. Sinyukov M.I. Gorenstein G.M. Zinovjev. In: Pis’maZhETF 28 (1978), p. 371. • G.M. Zinovjev D.V. Anchishkin M.I. Gorenstein. In: Phys. Lett. B 108 (1982), p. 47. • Resonance  M.I. Gorenstein A. Motornenko. In: arXiv:1604.04308 [hep-ph] (2016). • Rescattering • V.B. Kopeliovich. In: JETP Lett. 23 (1976), p. 313. • V.B. Kopeliovich. In: Phys. Rep. 139 (1982), p. 51. • M.A. Braun, V. V. Vechernin. In: Sov.J.Nucl.Phys 25 (1977), p. 676. • M.A. Braun, V. V. Vechernin In: Sov. J. Nucl. Phys. 43 (1986), p. 1016. • M.A. Braun, V. V. Vechernin. In: Sov. J. Nucl. Phys. 40 (1984), p. 1008. • M.A. Braun, V. V. Vechernin. In: J.Phys. G 19 (1993), p. 517. • Flucton • D. I. Blokhintsev, ZhETF 33, 1295 (1957). • V. Efremov. In: Phys.Part.Nuclei 13 (1982), p. 613. • R. Blankenbecler I.A. Shcmidt. In: Phys. Rev. D 16 (1988), p. 1318. • ….continued on the next page 

11. Theoretical approachesto mechanisms of cumulative particle production • Flucton and formation of cumulative particles from flucton • M.A. Braun, V. V. Vechernin. In: Nucl. Phys. B 427 (1994), p. 614. • M.A. Braun, V. V. Vechernin. . In: Phys. Atom. Nucl. 60 (1997), p. 432. • M.A. Braun, V. V. Vechernin. In: Phys. Atom. Nucl. 63 (2000), p. 1831. • M.A. Braun, V. V. Vechernin. In: Nucl. Phys. B (Proc. Suppl.) 92 (2001), p. 156. • M.A. Braun, V. V. Vechernin. In: Theor. and Math. Phys 139 (2004), p. 766. • V.V. Vechernin. In: AIP Conference Proceedings. Vol. 1701. 060020 (2016).

12. Short-Range Nucleon-Nucleon Correlations L.L. Frankfurt, M.I. Strikmann, Phys. Rep. 76, 215 (1981); ibid 160, 235 (1988). States of strongly overlapping nucleon wave functions in nuclei are commonly referred to as nucleon-nucleon short-range correlations .

13. 3-Nucleon Short Range Correlations (SRC) in DIS experiments/following Frankfurt-Strikman idea The DIS experiments [1] demonstrate in the A(e,e′) inclusive electron scattering the intrinsicpresence of SRC in the normal cold nuclear matter The ratios of inclusive 4.461- 4.471 GeV e+4He, e+12C and e+56Fe to e+3He scattering cross sections have been measured at 1 < xB < 3 in [1]. This is the first measurement of 3-nucleon SRC probabilities in nuclei. [1] K.S. Egiyan, etal., The CLAS Collaboration, Phys.Rev.Lett.96:082501,2006, [arXiv: nucl-ex/0508026] 23.2.17 13

14. Transverse momentum dependence of spectra of cumulative particles produced in pA 10GeV/c collisions and the Coherent Quark Coalescence Model [1] • Theobserveddependence of transverse • momentumspectraofcumulative • particlesproducedfrom“droplets”ofdense • nuclearmatter(cold QGP)isdifferentfor • protonsandpions • Experimentiswellreproduced • by the Coherent Quark Coalescence Model [1] • -- theconstituentquarkmassis taken • tobeequal300 MeV , see [1] • This succesfulCoherent Quark • Coalescence Model [1] could be also used • for the new predictions see further [1] V.V. Vechernin. In: AIP Conference Proceedings. Vol. 1701. 060020. 2016. [2] Experiment: see S.V. Boyarinov et al., Sov.J.Nucl.Phys. 46, 871 (1987) ;S.V. Boyarinov et al., Physics of Atomic Nuclei 57, 1379 (1994);S.V. Boyarinov et al., Sov.J.Nucl.Phys. 55, 917 (1992). 14

15. What is new proposed?

16. Hypotheses to be tested for Cumulative particles and Heavy flavourproduction mechanisms • A: Result of interactions of projectile with nuclear media (Rescattering? Resonances?Formation of “a fireball”?)… • B: Intrinsic presenceof rare configurations (few nucleon short-range correlations or fluctons) in the wave function of nucleus (“Drops of cold QGP”)? • C: Additional type of production of heavy flavour(and, in particular, of D0-meson) related to formation of cumulative particle from flucton • in string-fusion like mechanism 23.2.17 16

17. Study of correlations between cumulative particles and strangeness and/or charm forward production - thecumulativeprotonproductioninbackwardhemisphere - ssbarorccbarformationinforwardhemisphere Flucton fragmentation Theanalysisofthediagramsshowsthatalldonorquarks havea largevirtualityandmustinteractwiththeprojectile:M. A. Braun, V. V. Vechernin, Nucl. Phys. B 427, 614 (1994);Phys.Atom.Nucl. 60, 432 (1997); Theor.Math.Phys. 139, 766 (2004). Soonecanexpectanenhancedyieldofstrangeandcharmparticlesintheprocessoftheirhadronization.

18. Flucton cumulative fragmentation Formation of the donor strings (alldonorsinteractwiththeprojectile) [M.A. Braun, V.V. Vechernin, Phys.Atom.Nucl. 60, 432 (1997))]

19. Flucton cumulative fragmentation Cumulative particlemomentumneedstobecompensatedbylongitudinalmomentaofthedonors=>Donorstringsareshiftedtopositiverapidities 2) Cumulative fragmentationoffluctonneedsshrunkfluctonconfigurationin transverse plane[M.A. Braun, V.V. Vechernin, Theor.Math.Phys. 139, 766 (2004)] => Overlappingofdonorstrings - the donor strings - general valence quark strings Rapidity distribution of the donor strings (in laboratory frame) Transverse planedistributionofthedonorstrings Overlappingofdonorstrings String fusion  Enhanced productionofheavyflavors is expected due to Schwinger mechanism! e.g. strange production: [E.G. Ferreiro,C. Pajares, J.Phys.G23:1961-1968, (1997)]

20. UrQMD [1] brief overview • The Ultra Relativistic Quantum Molecular Dynamics (UrQMD) model is a transport model for simulating heavy ion collisions in the energy range from SIS to RHIC • - Strongly conserve quantum numbers and energy-momentum • - Can be run standalone or as afterburner • - Basic charm support • Some dependence on the reference frame (we used anti-lab for calculation and lab – for presenting results) • [1] S. A. Bass, et al, Prog. Part. Nucl. Phys. 41 (1998) 225-370; M. Bleicher, et al, J. Phys. G: Nucl. Part. Phys. 25 (1999) 1859-1896 20

21. UrQMD simulation of cumulative particles and D mesons p-C at plab=400 GeV/c UrQMD default

22. UrQMD: Cumulative spectra without and with D meson in the event • shows no correlations in UrQMD (except the energy conservation)

23. Summary and PLANS Summary • In spite of rather large wealth of experimental data the mechanism of cumulative particle production is still needed to be clarified • Two following directions of studies in pA collisions can be usefull (prospective):  -- The study of collision energy dependence of pT spectra of cumulative pions and protons in pA collisions at SPS and -- The study of correlations between the cumulative particle and strangeness or charm production Plans : • To continue theoretical studies of cumulative phenomena in the framework of Coherent Quark Coalescence Model and String Fusion Model. Compare the results with the available experimental data. • To evaluate the correlation strength between yields of cumulative particles and those relevant to heavy flavors production. • To continue model simulations (UrQMD,PHSD) for kinematics of possible correlations between the cumulative particle (in backward) and strangeness or charm yield

24. BACK-UP SLIDES

25. Why heavy flavours? In Pb-Pbcollisions: • Study of early stages of heavy-ion collisions • Probe for study thermalizationof QGP __ C C [1] T. Matsui and H. Satz, Phys. Lett. B 178 (1986) 416. [2] Helmut Satz, Calibrating the In-Medium Behavior of Quarkonia, arXiv: 1303.3493, 12 April 2013 [3] 2013 -- Berndt Mu ̈ller, arXiv:1309.7616

26. UrQMD simulation of cumulative particles and D mesons Details: p+Ccollisions at plab=400 GeV/c Anti-lab frame for calculation → boost to the lab frame for plots UrQMD default - enough to have cumulative particles Impact parameter b=0..3.5fm ~50% of empty events Statistics2·109after exclusion of empty events 26