Поляризованная странность нуклона М.Г.Сапожников Объединенный институт ядерных исследований, Дубна Вклад странных кварков в электрический и магнитный формфактор. - презентация

1 Поляризованная странность нуклона М.Г.Сапожников Объединенный институт ядерных исследований, Дубна Вклад странных кварков в электрический и магнитный формфактор нуклона не равен нулю (A4, G0) Поляризация глюонов – мала (СOMPASS) Пентакварков (антидекуплета)– нет !? (JLAB) Пентакварки в нуклоне– есть ! (Дьяконов, Петров) Cтранность в аннигиляции нуклонов (LEAR) Итоги и перспективы

2 Strangeness of the vacuum The vacuum strange quark condensate is as large as the light quark condensate: Ioffe B.L., Nucl.Phys. 1981, B188, 317, erratum 1981, B191, 591. Reinders L.J., Rubinstein H.R., Phys.Lett., 1984, B145, 108.

3 Strangeness of the nucleon S.Brodsky: Extrinsic – connected with gluons – perturbative gluons s s gluons Intrinsic – nonperturbative

4 Extrinsic strangeness Could provide s(x) / s(x) asymmetry (small, at three loops level) M. Glück, E. Reya, A. Vogt, Eur. Phys. J. C 5 (1998) 461–470.

5 The strange quarks contribution in the nucleon could be small or large, depending on the matrix element Ioffe B.L., Karliner M., Phys.Lett., 1990, B247, 387 Small – vector, tensor Large – scalar, pseudoscalar, axial vector

6 Strangeness of the nucleon: scalar channel Old N data: y= Lattice: y= Recent N data: y= ( Meissner U.-G., Smith G., hep-ph/ )

7 Strangeness of the nucleon: small Momentum fraction P s = 3% at Q 2 =5 GeV 2 (NuTEV)

8 G0 collaboration, nucl- exp/

9 s(r) ??

10 Is the nucleon strangeness polarized? Inclusive DIS Semi-inclusive DIS, positive polarization of the strange sea HERMES collaboration criticism of the procedure: A.Kotzinian. Phys.Lett. B552 (2003) 172 E.Leader, D.Stamenov PRD67 (2003) non-negative polarization is almost impossible

11 At LEAR experiments Strong violation of the OZI rule was found in pp pp, pp ( 3 S 1 ) pd n Is it depends on –spin –orbital angular momentum –momentum transfer –isospin?

12 negative polarization of strange quarks s s in nucleon , not as strangeonia production – via rearrangement both nucleons participated From spin triplet initial states: – L=0 - – L=1 – f 2 (1525) No additional from spin singlets

13 Квантовые числа s s пары в нуклоне EKKS original is better (phenomenological analysis) Chiral soliton model Из нуклона должны вылетать не, а - мезоны Должен возникнуть direct coupling (s s NN)

14 + p + p CLAS, hep-ex/ tensor polarization of 0 00 =0, if SCHC holds Anomalously large g NN | g NN /g NN | = 0.2 Direct NN coupling – the reasons?

15 Deeply bound kaon states T.Suzuki et al., nucl-ex/ He(K - stop, N) S 0 (3115),

16 production in DIS, target fragmentation Polarized strangeness model J.Ellis, D.Kharzeev, A.Kotzinian, Z.Phys. 1995, C65, 189; Large negative longitudinal polarization was predicted

17 production in DIS, target fragmentation NOMAD Collaboration Nucl. Phys. B588 (2000) 3 Nucl. Phys. B605 (2001) 3

18 S.Forte, SPIN-04

19 Strangeness of the nucleon: asymmetric? F. Olness et al., hep-ph/

20 Продольная поляризация (uds) Какой кварк(и) несет спин ? Два источника и две составные части поляризации гиперонов: + p + + X –Поляризованный мюон –Поляризованный кварк

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22 Measurements of longitudinal spin transfer to and at DIS P = S P b D(y)

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24 International research facility at GSI Rare isotope beams Antiproton storage ring Heavy ion collisions Plasma Physics Antiprotons – at

25 p + p + p p s s s s If it was normal quark reaction ( ) exp ~ 4 b why it so large? ( ( ) not measured)

26 pp JETSET (PS 202) Non-magnetic spectrometer, events is definitely different from KK or 4K Main contributions: –J P = 2 +, L( )=2, S( )=2 –J P = 2 +, L( )=0, S( )=2 –J P = 2 +, L( )=2, S( )=0 (resonance-like, m= MeV, =70 10 MeV) A.Palano, Workshop on Hadron Spectroscopy, Frascati, 1999, p.363

27 pp at PANDA Luminosity of HESR – L = cm -2 s -1 Cross section = 4 b at 1.4 GeV/c BR of charged mode =0.25 Registration efficiency = 0.25 N = L = = 50 s -1 The best world statistics will be overcome after 5 minutes of the running time

28 Polarized strangeness for PANDA opulent production of 0 ++ s s- meson. f 0 (1710) production due to shake-out R( / ) should increase with momentum transfer

29 Conclusions Strange degrees of freedom in the nucleon are not (all) small. Experimental data from COMPASS and NIS (now) and PANDA (in future) will help to determine the properties of the nucleon intrinsic strangeness. Everybody are welcome!