Spin physics experements at NICA ( Letter of Intent )

1. Spin physicsexperementsat NICA (Letter of Intent) O.Kouznetsov and I.Savin On behalf of the LoI drafting committee LHEP, JINR, Dubna QUARKS2014 2-8 June, Suzdal, Russia

2. List of LoI participants (>100) still is open for interested people R. Abramishvili1, V.V. Abramov6, F. Ahmadov1, R.R. Akhunzyanov1, V. A. Anosov1, N.V. Anfimov1, S. Anishchanka12, X. Artru15, A.A.Baldin1, V.G. Baryshevsky12, A. S. Belov5, D. A. Bliznyuk14, M.Bodlak8,A.V. Butenko1, A. P. Cheplakov1, I. E. Chirikov-Zorin1, G. Domanski10, S.V. Donskov6, V.V. Drugakov17, M. Dziewiecki10, A.V. Efremov1, Yu. N. Filatov1,3, V.V. Fimushkin1, M. Finger (jun.)7,1, M. Finger7,1, S.G. Gerassimov13, I.A. Golutvin1, A. L.Gongadze1, I. B. Gongadze1, M. I. Gostkin1, B.V. Grinyov14, A. Gurinovich12, A.V. Guskov1, A. N. Ilyichev17, Yu. I. Ivanshin1, A.V. Ivanov1, V. Jary8, A. Janata7,1,N. Javadov1, L. L. Jenkovszky4, V. D. Kekelidze1, D. V.Kharchenko1, A.P. Kobushkin4, B. Konarzewski10, A. M. Kondratenko2,M. A. Kondratenko2, I. Konorov13, A. D. Kovalenko1, O. M. Kouznetsov1, G. A. Kozlov1, A.D. Krisch16, U. G. Kruchonak1, Z.V. Krumshtein1, V.V. Kukhtin1, K. Kurek9, P. K. Kurilkin1, R. Kurjata10, L.V. Kutuzova1, N. K. Kuznetsov1, V. P. Ladygin1, R. Lednicky1, A. Lobko12, A.I. Malakhov1, J. Marzec10, J. Matousek7,G.V. Meshcheryakov1, V. A. Mikhaylov1, Yu.V. Mikhaylov6, P.V. Moissenz1, V.V. Myalkovskiy1, A. P. Nagaytsev1, J. Novy8,I. A.Orlov1, M. Pesek7, D.V. Peshekhonov1, V. D. Peshekhonov1,V. A. Polyakov6, Yu.V. Prokofichev1, A.V. Radyushkin1, V. K. Rodionov1, N. S. Rossiyskaya1, A. Rouba12,A. Rychter10, V. D. Samoylenko6, A. Sandacz9, I. A. Savin1, G. A.Shelkov1, N. M. Shumeiko17, O.Yu. Shevchenko1, S.S. Shimanskiy1, A.V. Sidorov1, M. Slunechka7,1, V. Slunechkova7,1, J. Soffer11, G.I. Smirnov1, N. B. Skachkov1, A.A. Solin17,A.V. Solin17, E. A. Strokovsky1, O. V. Teryaev1, M. Tomasek8,N.D.Topilin1, A.V.Turbabin5, Yu.N. Uzikov1, M.Virius8, V.Vrba8, M.V. Zavertyaev13, K. Zaremba10, E.V. Zemlyanichkina1, P.N. Zhmurin14, M. Ziembicki10, V. N. Zubets5, I. P.Yudin1 QUARKS2014

3. Affiliations • 17 National center of Particle and High Energy Physics, Belarusian State University, Minsk • 16University of Michigan, USA • 15CNRS, Lyon, France • 14Institute for Scintillation Materials, NAS, Kharkov, Ukraine • 13Lebedev Physics Institute, Moscow, Russia • 12Research Institute for Nuclear Problems, Minsk, Belarus • 11Temple University, Philadelphia, USA • 10Warsaw University of Technology, Institute of Radio electronics, Warsaw, Poland • 9National Center for Nuclear Research, Warsaw, Poland • 8Technical University, Faculty of Nuclear Science and Physics Engineering, Prague, Czech Rep. • 7Charles University, Faculty of Mathematics and Physics, Prague, Czech Republic • 6Institute for High Energy Physics, Protvino, Russia • 5Institute for Nuclear Research of Russian Academy of Sciences, Moscow, Russia • 4Bogolyubov Institute for Theoretical Physics, Kiev, Ukraine • 3Moscow Institute of Physics and Technology, Dolgoprudny, Russia • 2Science and Technique Laboratory Zaryad, Novosibirsk, Russia • 1Joint Institute for Nuclear Research, Dubna, Russia  Expressed of Interest: INFN Italy (Torino), Belorussia (Gomel States University), Moscow States University, St. Petersburg (Gatchina), ITEP Moscow QUARKS2014

4. JINR in Spin Studies Historical remarque Started in early 50-th from: - experiments at Laboratory of Nuclear Problems with polarized beamsand targets at Synchrocyclotron, -pioneering Development of super-frozen polarized targets (next slide), -experiments at Serpukhov 70 GeV proton Synchrotron, -experiments at Synchrophasotron with movable polarized target and other fixed target experiments. Continued with JINR participation in Nucleon Spin structure experiments: SMC, COMPASS-I, COMPASS-II (SPS CERN), HERMES (DESY), STAR (BNL). Accompanied by theoretical developments (Lapidus, Ryndin, Kopeliovich, Efremov, Teryaev, Sidorov, Goloskokov…) and Organization of biannual International Spin Workshops DSPIN (1981-2013), SPIN2012 conference, DSPIN 2013: http://theor.jinr.ru/~spin/2013/ QUARKS2014

5. Historical remarque Made in JINR: polarized targets • Pioneering development of frozen targets • by group of B.Neganov at Dubna in 1965 • has reached the required super low temperature of ~20 mK. • Based on his idea of dilution of He3 in He4 • (the dilution refrigerator) • B.Neganov, N.Borisov and M.Liburg, Sov.Phys. JETP23 (1966)959 B.S.Neganov 1928-2012 • The first frozen polarized target in the experiments at the Synchrocyclotron QUARKS2014

6. 2. Physics motivations • 2.1 Twist-2 PDFs of the nucleon • 2.2. Nucleon spin structure studies using the Drell-Yan mechanism • 2.3. New nucleon PDFs and J/Ψ production mechanisms. • 2.4. Direct photons. • 2.5. Spin-dependent high-pTreactions. • 2.6. Spin-dependent effects in elastic pp and dd scattering. • 2.7. Spin-dependent reactions in heavy ion collisions. • 3. Requirements to the NUCLOTRON-NICA complex • 4. Requirements to the Spin Physics Detector (SPD) • 4.1. Event topologies. • 4.2. Possible layout of SPD. • 4.3. Trigger system. • 4.4. Local polarimeters and luminosity monitors. • 4.5. Engineering infrastructure. • 4.6. DAQ. • 4.7. SPD reconstruction software. • 4.8. Monte Carlo simulations. • 4.9. Slow control. • 4.10. Data accumulation, storing and distribution. Outline(LoI) • 5. Proposed measurements with SPD • 5.1. Estimations of DY and J/Ψ production rates. • 5.2. Estimations of direct photon production rates. • 5.3. Rates in high-pTreactions. • 5.4. Rates in elastic pp and dd scattering. • 5.5. Feasibility of the spin-dependent reaction studies in heavy ion collisions. • 6. Time scale of the Project • 7. Conclusion QUARKS2014

7. 2. Physics motivations QUARKS2014

8. Basic twist-2 PDFs of the nucleon • Taking taking into account the quark intrinsic transverse momentum kT, • at LO 8 PDFs are needed for a full description of the nucleon structure • Vanish upon integration over kTexcept f1 , g1 , and h1 aka Sivers Boer– Mulders Transversity chiral -odd T -odd Pretzelosity QUARKS2014

9. Definitions of twist-2 PDFs of the nucleon f1 - density of partons in non-polarized nucleon, (x, Q2); g1-helicity , longitudinal polarization of quarks in longitudinally polarized nucleon; h1 -- transversity, transverse polarization of quarks in transversely polarized nucleon ; f┴1T- Sivers, correlation between the transverse polarization of nucleon (transverse spin) and the transverse momentum of non-polarized quarks; g┴1T- worm-gear-T, correlation between the transverse spin and the longitudinal quark polarization ; h┴ 1 - Boer-Mulders, distribution of the quark transverse momentum in the non-polarized nucleon ; h┴1L - worm-gear-L, correlation between the longitudinal polarization of the nucleon (longitudinal spin) and the transverse momentum of quarks ; h┴1T - pretzelosity, distribution of the transverse momentum of quarks in the transversely polarized nucleon QUARKS2014

10. Status of f1 and g1 PDFs f1 measured from Deep Inelastic lepton Scattering (DIS) l + N l’ +X, nucleoncan be polarized . R(x,Q2) and F2(x,Q2) have been measured by the collaborations SLAC, EMC, BCDMS, NMC, ZEUS, H1 and others. In QCD: F2 (x, Q2) = x∑qe2 q [q(x, Q2) + anti-q(x, Q2)], q=u, d, s. f1 PDFs for each parton are determined from the QCD analysis of all DIS data. Parton (density) distributions in non-polarized nucleons at Q2=10 GeV2 vs. x. QUARKS2014

11. Status of f1 and g1 PDFs g1 measured from  pol separated off  tot in so-called asymmetries. The cross sections difference, //, for two opposite longitudinal target polarizations is given by the expression: . . connected with the longitudinal asymmetry, A// ,defined as which, in the first approximation, related to g1: • A// /D ≈ A1 ≈ (g1 –γ2 g2)/F1 ≈ g1 /F1, The QPM expression for virtual photon asymmetry A1: QUARKS2014

12. g1(x,Q2) F2(x,Q2) QUARKS2014

13. Status of PDFs: global analyses Parton helicity distributions in longitudinally polarized nucleon at Q2=10 GeV2vs x Parton density distributions in non-polarized nucleons at Q2=10 GeV2vs x. QUARKS2014

14. The knowledge about the transversity & Sivers PDFs is rather limited QUARKS2014

15. transversity PDF Collins asymmetry Collins FF COMPASS & HERMES results QUARKS2014

16. Siversasymmetry Sivers PDF COMPAS &HERMES results QUARKS2014

17. Transversity PDF Global fit result: COMPASS & HERMES & BELL Sivers PDF Global fit result: COMPASS & HERMES &unpol. FF QUARKS2014

18. No data : Pretzelosity PDF h┴1T Worm-gear-L h┴1L Worm-gear-T g┴1T Boer-Mulders h┴ 1 • Concluding, one can summarize that precision measurement at NICA the collinear and TMD PDFs can be the main subject of the NICA SPD spin program. N.B.Thepretzelosity PDF would give new information on possible role of the constituent’s orbital momentain resolution of the nucleon spin crisis. It should be noted that Sivers PDF sensitive to orbital angular momentum also. QUARKS2014

19. 2.2. Nucleon structure studies using the Drell-Yan mechanism The parton model diagrams of the di-lepton production in collisions of hadrons Ha (Pa ,Sa) with hadrons Hb (Pb,Sb) . The constituent quark (anti-quark) of the hadron Ha annihilates with constituent anti-quark (quark) of the hadronHbproducing the virtual photon which decays into a pair of leptons l± (electron-positron or µ±). The hadron spectator systems Xa and Xb are usually not detected. Both diagrams have to be taken into account. where Pa(Pb) and Sa(Sb) are the momentum and spin of the hadronHa(Hb), while l(l’) and λ(λ’) are the momentum and spin of the lepton, respectively. QUARKS2014

20. The kinematics of the Drell-Yan process is considered usually in the Collins-Soper (CS) reference frame [ J.C. Collins, D.E. Soper, and G. Sterman, Nucl. Phys. B250, 199 (1985).] Collins-Soper plane Polarization plane Lepton plane Results of the most complete theoretical analysis of this process [S. Arnold, A. Metz and M. Schlegel, Phys.Rev. D79 (2009) 034005 [arXiv:hep-ph/0809.2262] are used . QUARKS2014

21. The X-section of the DY pair’s production in the QPMvia LOPDFs isrewritten by us in the more convenient variables with a change of notations of the azimuthalanglescorresp.to CS rf. . are the SFs, depend on four variables Pa·q, Pb·q, qT and q2or on qT , q2and the Bjorken variables of colliding hadrons, xa, xb , , y is the cm rapidity. QUARKS2014

22. The equation on previous slide include 24 leading twist SFs. Each of them is expressed through a weighted convolution, C, of corresponding leading twist TMD PDF in the transverse momentum space: where kaT(kbT) is the transverse momentum of quark in the hadronHa (Hb) and f1 (f2) is a TMD PDF of the corresponding hadron. Expressions for all leading twist SFs of quarks and antiquarks are given in the text of LoI. f.e. in the unpolarized case: where h┴ 1 is the Boer-Mulders PDF for quarks & anti-quarks. QUARKS2014

23. 8 asymmetries to be measured: ALU, AUL, ATU , AUT, ALL, ATL, ALT, ATT QUARKS2014

24. In above expressions: cross section σpqwith superscripts: horizontal arrows - for positive (negative) longitudinal beam polarizations, vertical arrows - for transvers beam polarization , 0 - for the non-polarized hadr . --amplitude of SF modulation Applying the Fourier analysis to the measured asymmetries, one can separate each of all ratios . Extraction of different TMD PDFs from these ratios is a task of the global analysis since each of the SFsis a result of convolutions of different TMD PDFs in the quark transverse momentum space. For this purpose one needs either to assume a factorization of the transverse momentum dependence for each TMD PDFs, or to transfer them to impact parameter representation and to use the Bessel weighted TMD PDFs. QUARKS2014

25. The large number of independent SFs to be determined from the polarized DY processes at NICA (24 for identical hadrons in the initial state) is sufficient to map out all eight leading twist TMD PDFs for quarksand anti-quarks. This fact indicates the high potential of the polarized DYprocess for studying new PDFs. This process has also a certain advantage over SIDIS which also capable of mapping out theleading twist TMD PDFsbut requires knowledgeof fragmentation functions. The transverse single spin asymmetries depending on the Structure Functions are of the particular interests. The both SFs contain the Sivers PDFwhich was predicted to have the opposite sign in DY as compared to SIDIS. As the sign reversal is at the core of our presentunderstanding of transverse single spin asymmetries in hard scattering processes, the experimental check of this prediction is of the utmost importance. QUARKS2014

26. A number of conclusions can be drawn comparing some asymmetries to be measured. Let us compare the measured asymmetries ALUand AUL and assume that during these measurements the beam polarizations are equal, i.e. |SaL|=|SbL| and hadrons a,b are identical. Then one can intuitively expect that the integrated over xa and xb asymmetries ALU = AUL. Similarly, comparing the asymmetries ATUand AUTor ATLand ALT one can expect that FTU = FUT and F TL= FLT . Tests of these expectations would be a good check of the parton model approximations. QUARKS2014

27. Future DY experiments in the world QUARKS2014

28. 2.4. Direct photons. Direct photon productions in the non-polarized and polarized pp (pd) reactions provide information on the gluon distributions in nucleons VertexHcorrespondsto q +qbar →γ+Xorg+q→γ+Xhardprocesses. One can show that the polarized gluon distribution (Sivers gluon function)can be extractedfrom measurement of the transverse single spin asymmetry AN of order few %. Via double spin asymmetry ALL a gluon polarization in the nucleon: QUARKS2014

29. 2.7. Spin-dependent reactions in heavy ion collisions The hyperons & vector mesons polarization have asignificantsize (?) From a theoretical point of view the origin of sizable hyperon polarization in p+A and A1+A2 collisions represents a significant problem since in the perturbative QCD it is expected to be small Transverse polarization PN vs. xF of Λ from the reaction Au+Au→ Λ↑ +X at RHIC Au+Au Cu+Cu S+S Chromo-Magnetic Polarization of Quarks (CMPQ) model Predictions for PN vs. η for the reaction A1+A2→ Λ↑ +X at √s=7 and 9 GeV Systematic studies of inclusive transverse polarizations of hyperons and vector mesons vs. kinematic variables, energy and atomic weight of colliding beam can be performed at SPD. QUARKS2014

30. 3. Requirements to the NUCLOTRON-NICA complex Beams.The following beams will be needed, polarized and non-polarized: pp, pd, dd, pp, pd , pp, pd , dd. Beam polarizations both at MPD and SPD: longitudinal and transversal. Absolute values of polarizations should be (90-50)%.The life time of the beam polarization should be long enough ≥24h. Measurements of Single Spin and Double Spin asymmetries in DY require running in different beam polarization modes: UU, LU, UL,TU, UT,LL ,LT and TL (spin flipping for every bunch or group of bunches should be considered). Beam energies: pp(spp) = 12 ÷ ≥ 27 GeV (5 ÷ ≥12.6 GeV kinetic energy), dd(sNN) = 4 ÷ ≥13.8 GeV (2 ÷ ≥5.9 GeV/u ion kinetic energy). Asymmetric beam energies should be considered also. Beam luminosities: in the pp mode: Laverage 1·1032 cm-2s-1 (at spp = 27 GeV), in the dd mode: Laverage 1·1030 cm-2s-1 (at sNN = 14 GeV). QUARKS2014

31. The NICA Complex QUARKS2014

32. Possible NICA structure for polarized proton and deuteron beams The novel scheme of the polarization control at NICA, suitable for protons and deuterons, is based on the idea of manipulating polarizedbeams in the vicinity of the zero spin tune. This approach is actively developed at JLAB for the 8-shaped ring accelerator project. The zero spin tune is a natural regime for the mentioned case. To provide zero spin tune regime at the collider of the racetrack symmetry, it is necessary to install two identical Siberiansnakes in the opposite straight sections QUARKS2014

33. NICA pp-collisions peak luminosity 29 November 2012 (I.N.Meshkov) The number of particles reaches a value about 2.2∙1013 in each ring and the peak luminosity reaches Lpeack = 2∙1032 cm-2s-1 at 12.7 GeV QUARKS2014

34. 4. Requirements to the spin physics detector (SPD) Possible layout of SPD includesmore or less standard detectors. To minimize the time and the cost of the Project the versions of already developed and produced detectors for another experiments as COMPASS, PANDA, MPD-NICA etc. should be used as much as possible QUARKS2014

35. Magnet toroid HADRON & MUON DETECRORS solenoid ECAL VERTEX DETECTOR,SILICON TRACKIG, STRAW & DC The “almost 4π geometry” requested by DY and direct photons can be realized in the solenoid version of SPD if it has overall length and diameter of about 6 m. QUARKS2014 Fig. 5.13: possible view of SPD with the solenoid magnet.

36. Vertex detector The most obvious version of vertex detector (VD) is a silicon one. Several layers of double ­sided silicon strips can provide a precise vertex reconstruction and tracking of the particles before they reach the general SPD tracking system. The design should use a small number of silicon layers to minimize the radiation length of the material. With a pitch of 50-100 µm it is possible to reach a spatial resolution of 20-30 µm. Such a spatial resolution would provide 50-80 µm for precision of the vertex reconstruction. This permits to reject the secondary decay vertexes. Tominimizeabackgroundinthe DY dimuonsamplefromπ- µ decays, thefirstdetectionplaneof VD shouldbeasclosetothebeamaspossible. QUARKS2014

37. Tracking There are several candidates for a tracking system: conventional drift chambers (DC) and their modification – thin wall drift tubes (straw chambers). The DCs are the good candidates for tracking detectors in the end cup parts of SPD, while straw chambers are the best for the barrel part. Two groups have developed the technology of straw chamber production at JINR with two-coordinate reed out. The radial coordinate determination is organized via the electron drift time measurement while the measurement of the coordinate along the wire (z-coordinate) uses the cathode surface of the straw. Both technologies provide a radialcoordinateresolutionof 150-200 µmperplane. QUARKS2014

38. DVCS+BH ECAL1&2 New large-angle electromagnetic calorimeter for COMPASS is a good candidate for SPD also Requirements - Photon energy range 0.2- 30 GeV - Size: 360cm x 360cm ; - Granularity 4x4 – 6x6cm2 - Energy resolution<10.0%/√E (GeV)    - Thickness < 50 cm, - AMPD readout, Insensitive to the magnetic field. new shashlyk modules for tests in 2011 109 plates made of Sc 0.8 mm /Pb 1.5 mm AMPD, Avalanche Micropixel Photo Diodes, 3 x 3 mm2,densityof pixels 40 000/mm2 251mm or 15 radiation length Total length 470mm withelectronics 342 mm QUARKS2014

39. Hadron (muon) detectors • A system of mini-drift chambers interleaved with layers of iron and called the Range System (RS) is developed at JINR for FAIR/PANDA .It can be used in the barrel part of SPD as a hadron and (or) muon detector The hadron and muon detectors in the end caps part of SPD are to be identified. As candidates for these detectors, the COMPASS muon wall can be considered. It consists of two layers of mini-drift chambers with a block of absorber between them. QUARKS2014

40. 5. Proposed measurements • with SPD. Typical di-lepton invariant mass spectrum We propose to perform measurements of asymmetries of the DY pairs production in collisions of polarized protons and deuterons which provide an access to all collinear and TMD PDFs of quarks and anti-quarks in nucleons. The measurements of asymmetries in production of J/Ψ and direct photons will be performed simultaneously with DY using dedicated triggers. The set of these measurements will supply complete information for tests of the QPM of nucleons at the twist-two level with minimal systematic errors. QUARKS2014

41. 5.1. Estimations of DY production rates To estimate the precision of measurements, the set of original software packages for MC simulations, including generators for Sivers , Boer-Mulders and transversity PDFs were developed. With these packages we have generated a sample of 100K D­Y events (~ 1 year of data taking) for comparison with expected asymmetries. Cross section (left) and number of DY events (right) versus the minimal invariant mass of lepton pair for various proton beam energies. QUARKS2014

42. 5.1. DY, J/ and total pp X-sections In the energy range of NICA the total cross section of pp interactions is almost constant, about 40 mb. The expected event rates at the luminosity1032 sm-2 s-1 will be 4·106 per second. • Cross section of pp interaction versus QUARKS2014

43. 5.1. Projections for Sivers & Boer-Mulders asymmetries Estimations of Boer-Mulders asymmetry Estimated Sivers asymmetry The solid and dotted curves correspond to the first and second versions of the evolution model, respectively.. Numbers I, II, III denotecorresponding fits. =26 GeV and Q2 = 15 GeV2. Points show the expected errors obtained with 100K of events. QUARKS2014

44. 5.2. Estimations of direct photon production rates ANandALL could be measured at SPD with statistical accuracy ~0.11% and ~0.18%, respectively, in each of 18 xF bins (-0.9< xF< +0.9). Large statistics of events provide opportunities to measure the asymmetries as a function of xFand pT. QUARKS2014

45. CONCLUSION 1. The comprehensive program of the nucleon structure study is suggested. It can be realized at NICA using the polarized proton and deuteron beams. The text of LoI is almost complete. • 2. The participants of the LoI have submitted the document for an extensive discussions at JINR • EU-Russia-JINR @ Dubna Round Table, Dubna, 3-5 March LHEP Seminar, 7 March & LHEP NTS, 20 March & LNP Seminar, 23 April & LIT Seminar, 24 April & LTPH Seminar, 22 May & NTS JINR, 23 May 3. Presentation of LoI at the JINR PAC on particle physics is foreseen for 25 June 2014. 4. The list of participants still is open for interested people. 5. The draft of LoI is available on request (Igor.Savin@cern.ch) QUARKS2014

46. New collaborators, welcome! NICA accelerator complex FT experiment area Collider New Linac Nuclotron Booster Lu 20 QUARKS2014

47. QUARKS2014

48. NICA construction works looks feasible. QUARKS2014

49. Back up slides QUARKS2014

50. New spin physics facility at JINR. JINR developing the new accelerator facility “NICA Complex” providing intensive beams of relativistic ions uptoAu with max energy up to √SNN= 11 GeV (Au79+)and polarized protons and deuterons. Main targets of “NICA Complex”studies: - hot and dense baryonic matter, - nucleon spin structure, - polarization phenomena in heavy ion collisions in fixed target and collider experiments. For last ones: • ppspp = 12 ÷ 27 GeV (5 ÷ 12.6 GeV kinetic energy ) • dd sNN = 4 ÷ 13.8GeV (2 ÷ 5.9 GeV/u ion kinetic energy ) • Laverage1·1032cm-2s-1(at spp = 27 GeV) QUARKS2014