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Strangeness of the nucleon

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What we know about the nucleon strangeness. LEAR problems and polarized intrinsic strangeness ... PS 185 at LEAR. Polarized proton target. Dnn spin transfer ... – PowerPoint PPT presentation

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Title: Strangeness of the nucleon


1
Strangeness of the nucleon
  • M.G. Sapozhnikov
  • Joint Institute for Nuclear Research, Dubna
  • What we know about the nucleon strangeness
  • LEAR problems and polarized intrinsic strangeness
  • Is it polarized? Is it strangeness?
  • Exotic baryons and nucleon strangeness

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
  • Could not disappear (completely)
  • S.Brodsky
  • Extrinsic connected with gluons perturbative
  • q ? gluons ? s ?s
  • Intrinsic connected with valence quarks
    nonperturbative
  • generated by cf. instanton effects

4
  • 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

5
Strangeness of the nucleon small
  • Momentum fraction Ps 4 at Q220 GeV2
  • (CCFR)
  • Electric and magnetic form factors at Q20.48
    (GeV)2 (HAPPEX)
  • GE(s) 0.39 GM(s) 0.025 ?0.020 ? 0.014
  • Magnetic form factor at Q20.1(GeV)2 (SAMPLE)
  • GM(s) 0.37 ?0.20 ? 0.26 ? 0.07

6
The ?-term
  • Matrix element of the scalar current
  • No scalar probe to measure
  • Low-energy current algebra theorem
  • F2?92.4 MeV, ?s-u q,q momenta of
    scattering ?
  • ?(t) scalar formfactor
  • ??(0)/2m
  • R?? - the reminder (unknown)
  • Main idea to measure A(t,?) in a region where
    R?? is small
  • Cheng-Dashen point ?0, t2m?2 - R?? 0 (0, at
    the tree level)

7
How to measure the ?-term?
  • To measure A(t,?)
  • To extrapolate it at t2m?2 , ?0 - ??CD2 MeV
  • To extrapolate it at t0, ?0 - ??R 15 MeV
  • ? ? ??CD ??R
  • ? 64 8 MeV measured
  • ? 36 7 MeV ?- calculated
  • Small discrepance 64 8 ? 53 7 MeV

8
  • y0.2, ? (36 7)/0.8 45 9 MeV
  • ? ? ??CD ??R

9
Strangeness of the nucleon large
  • Old ?N data y0.2?0.2
  • Lattice y0.36 ?0.03
  • Recent ?N data y0.36-0.48
  • (Meissner U.-G., Smith G., hep-ph/0011277)

10
Strangeness of the nucleon axial-vector part
  • Inclusive DIS
  • Semi-inclusive DIS, positive polarization of the
    strange sea
  • HERMES, hep/ex-0307064
  • criticism of the procedure A.Kotzinian.
    Phys.Lett. B552 (2003) 172
  • E.Leader, D.Stamenov PRD67 (2003) 037503
  • non-negative polarization is almost impossible

11
The OZI rule
  • Processes with disconnected quark lines are
    suppressed
  • It is not possible to produce ?ss meson in the
    non-strange particle interactions.
  • The ? - meson production is only due to light
    quarks admixture
  • R(?/?)tg2(?-?I)4.2 10-3
  • Weighted average of all experimental data
  • ?N
  • R(?/?)(3.30?0.34)10-3
  • NN
  • R(?/?)(12.78?0.34)10-3
  • ?NN
  • R(?/?)(14.55?1.92)10-3

12
At LEAR experiments
  • Strong violation of the OZI rule was found in
  • ?pp???
  • ?pp???,
  • ?pp??? (3S1)
  • ?pd??n
  • Is it depends on
  • spin
  • orbital angular momentum
  • momentum transfer
  • isospin?

13
  • negative polarization of strange quarks
  • ?s s in nucleon - 0, not as ?
  • strangeonia production via rearrangement
  • both nucleons participated
  • From spin triplet initial states
  • L0 - ?
  • L1 f2(1525)
  • No additional ? from spin singlets

14
Polarization of nucleon strangeness
  • Sz-1

15
Polarized intrinsic strangeness model
  • J.Ellis, M.Karliner,D.Kharzeev, M.Sapozhnikov,
    Phys.Lett., 1995, v.B353 , p. 319 Nucl.Phys.
    A673 (2000) 256
  • antiproton annihilation at rest, predictions
    for NN
  • M.Alberg, J.Ellis, D.Kharzeev, Phys.Lett. 1995,
    B356, 113
  • Spin transfer Dnn in
  • J.Ellis, D.Kharzeev, A.Kotzinian, Z.Phys. 1995,
    C65, 189
  • J.Ellis, A.Kotzinian, D.Naumov , Eur.Phys.J. C25
    (2002) 603
  • Longitudinal polarization of ?-hyperons in DIS
  • For recent review V.P.Nomokonov,
    M.G.Sapozhnikov,
  • hep-ph/0204259, 2002,
  • Phys. of Elementary Particles and Atomic
    Nuclei, 34 (2003) 184

16
List of correct predictions
  • ?NN sector
  • ?pp???0, 3S11P1 15 CB,OX
  • ?pp?f2 ?0, P/S 10 OX, CB in flight
  • ? and ? production is different
  • ??0(1P1)lt7 ? ?0(1P1)37 OX
  • ? production energy dependence, OX ?np
  • ?pp ? ? ?, JPC2 dominance, JETSET
  • ?pp ? ???, suppression of spin singlet
  • Fs(0.1?7.3) 10-3 PS 185
  • Pontecorvo reactions ?pd ? ? n OX,CB
  • ?pp ?KK selection rule CB

17
List of correct predictions-2
  • NN sector
  • OZI violation in pp?pp?(?) at threshold, 14
    times DISTO
  • ? and ? angular distributions are different COSY
    TOF
  • Negative Dnn DISTO
  • OZI violation in pd?3He ?(?), 20 times SPES4
    Saturne
  • Negative longitudinal polarization of ? in ?DIS
    NOMAD

18
List of problems
  • Strong violation in ?pp???
  • Initial state spin singlet 1S0
  • M.Rekalos problem in ?pp???
  • M. Rekalo, J. Arvieux and E. Tomasi-Gustafsson,
    Z.Phys. A357
  • (1997) 133.
  • Spin transfer Dnn in ?p ppol ? ? ??
  • Dnn?0, Knn gt0
  • Spin of proton is transferred to ??, not to ?
  • CLAS,
  • The spins of s and ?s are anti-aligned.

19
Spin transfer in ?p ppol ? ? ??
  • PS 185 at LEAR
  • Polarized proton target
  • Dnn spin transfer from proton to ?
  • Knn spin transfer from proton to ??

20
M.Rekalos problem
  • ?pp??? from 3S1 is not possible without either
    spin flip of s-quark or positive polarization of
    strange quarks
  • ?p p? ? ?

S
ssbar
21
Polarization of nucleon strangeness
  • Sz-1

22
Two components of polarized strangeness
  • Sz-1 and Sz0
  • Seems to solve all the problems
  • ?pp???, spin singlet 1S0 rearrangement Sz-1
    and Sz0
  • M.Rekalos problem in ?pp??? - rearrangement two
    Sz0 components
  • CLAS, The spins of s and ?s are anti-aligned
  • shake-out of Sz0
  • But

23
Longitudinal polarization of ?-hyperons in DIS
  • J.Ellis, A.Kotzinian, D.Naumov , Eur.Phys.J. C25
    (2002) 603
  • Fit of all existing data on ?? production
  • Ps Csq Pq
  • Sz-1 ? Csq-1
  • Csq-0.350.05
  • If W(Sz-1 ) W(Sz0) ? Csq-1/3

24
New problems
  • Equal probabilities not 21, as expected
  • No dependence on spin of the initial state spin
    singlets and spin triplets are equal
  • Strange quarks polarization seems diluted
  • Spin-transfer for ? and?? should be different
  • more negative and large for ??
  • May be only Sz0 component exists?

25
Polarized strangeness for the diquark
  • Sz-1 and Sz0

26
Baryons in Chiral Soliton Model (from
J.Ellis talk at Gernoble, 2004)
  • Baryons clouds of p, K, ?8 mesons
  • ? many ssbar pairs
  • Baryon spin due to rotation of meson cloud
  • ? Spin orbital angular momentum
  • ? no ?0 coupling
  • ? ssbar pairs polarized
  • Exotic baryons ? excitations of meson cloud

27
Models of Nucleon Structure (from J.Ellis
talk at Gernoble, 2004)
  • Naïve quark model
  • MQ 300 MeV
  • Wave function QQQ
  • Sea of extra qqbar pairs generated perturbatively
  • Usual SU(3) multiplets
  • Explains OZI rule
  • Proton spin Sum of valence quark spins
  • Sum of quark spins ½
  • Few intrinsic ssbar
  • Chiral soliton model
  • MU,D few MeV,
  • MS 100 MeV
  • Intrinsic qqbar pairs in nucleon wave function
  • Exotic SU(3) multiplets
  • Evasions of OZI rule
  • Proton spin Orbital angular momentum
  • Sum of quark spins 0
  • Many polarized ssbar

28
Prediction of the chiral soliton model for the
nucleon
  • At 1/N? ??, mq 0, leading order
  • ?? ?u ?d ?s 0
  • At the real world - ?? ?0.2
  • ?u ?d gt0, ?s lt 0,
  • Inclusion gluons - ?G 0
  • S.Brodsky, J.Ellis, M.Karliner, Phys.Lett. B206
    (1988) 309
  • J.Ellis, M.Karliner, Phys.Lett. B213 (1988) 73

29
Prediction of the chiral soliton model for the
nucleon-2
  • Large scalar strangeness
  • J. Donoghue, C. Nappi, Phys. Lett. B 168 (1986)
    105

30
Prediction of the chiral soliton model for the
nucleon-3
  • From masses ?(1530) and ??? (1860) one could
    found the value of sigma-term ?73 ???
  • J.Ellis, M.Karliner, M.Praszalowicz,
    hep-ph/0401127
  • A lot of exotic baryons.

31
Spectrum of Antidecuplet 27 Baryons
Using ? and ?-- masses
J.E., Karliner Praszalowicz hep-ph/0401127
32
Exotic Baryon Spectrum s Term
Implications for strangeness
Chiral soliton mass formula
numerically
33
Pentaquarks or exotic baryons?
  • NQM 4 q ?q in S-wave negative parity
  • Chiral solitons positive parity
  • Jaffe-Wilzcek
  • (qq)-(qq)- ?q
  • flavor diquark
  • Lipkin-Karliner
  • (qq)- (qqq)
  • No explanation of narrow width

M.Polyakov, COMPASS Workshop, 2004
34
Pentaquarks and polarized strangeness
  • C10 0.197, C27 0.154

35
  • Jaffe-Wilczek model
  • ltPsgt0, ltPsbargt-0.0086
  • Karliner-Lipkin
  • ltPsgt-2/27, ltPsbargt2/27
  • (A.Kotzinian)

36
Polarized strangeness for the diquark
  • Sz-1 and Sz0

37
  • All problems solved

 
38
Conclusions
  • New exotic baryons open new era of hadron
    spectroscopy
  • It is not merely a prediction of 37 new states.
  • It is new look on the nature of baryon.
  • All these states could be produced at JINR
    Nuclotron and detected at the NIS spectrometer.
  • Everybody are welcome!

39
The ?-term
  • Measure of the QCD chiral symmetry breaking
  • mq0, ?0
  • Mp ? M0 ? Ms
  • M0 (767 ?110) ???
  • ? (45 ?8) ???
  • Ms 130 ??? (B.Borasoy,
    U.Meissner, Ann.Phys. 254 (1997) 192)

40
NIS at JINR Nuclotron
  • To measure pp?pp? and pp?pp? at 30-100 MeV above
    the thresholds
  • If R(?/ ?) gtgt R(OZI),
  • Opulent ? production is not pure annihilation
    phenomenon intrinsic strangeness exists.
  • If R(?/ ?) R(OZI),
  • Opulent ? production is pure annihilation
    phenomenon effect of gluons.
  • .
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