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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

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.

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

- 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

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

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)

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

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

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)

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

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

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?

- 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

Polarization of nucleon strangeness

- Sz-1

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

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

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

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.

Spin transfer in ?p ppol ? ? ??

- PS 185 at LEAR
- Polarized proton target
- Dnn spin transfer from proton to ?
- Knn spin transfer from proton to ??

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

Polarization of nucleon strangeness

- Sz-1

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

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

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?

Polarized strangeness for the diquark

- Sz-1 and Sz0

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

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

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

Prediction of the chiral soliton model for the

nucleon-2

- Large scalar strangeness
- J. Donoghue, C. Nappi, Phys. Lett. B 168 (1986)

105

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.

Spectrum of Antidecuplet 27 Baryons

Using ? and ?-- masses

J.E., Karliner Praszalowicz hep-ph/0401127

Exotic Baryon Spectrum s Term

Implications for strangeness

Chiral soliton mass formula

numerically

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

Pentaquarks and polarized strangeness

- C10 0.197, C27 0.154

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

Polarized strangeness for the diquark

- Sz-1 and Sz0

- All problems solved

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!

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)

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. - .