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Study of OZI Rule Violation in Meson Production Reactions at PANDA Facility - First FRRCFellows Seminar

Explore violations of the OZI rule in meson production reactions at the PANDA Facility during the First FRRCFellows Seminar in Moscow, June 2009. Understanding the complexities of meson mixing and production processes in hadronic interactions.

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Study of OZI Rule Violation in Meson Production Reactions at PANDA Facility - First FRRCFellows Seminar

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  1. pdn, ωn, K+-, K0  reactions at PANDA facility Yu. Rogov, First seminar of FRRCFellows FAIR – Russia Research Center, Moscow June, 9 - 10, 2009

  2. OZI rule* • NN→φπ is forbidden, NN→ωπ is allowed • φ production is possible only via mixing, because φ and ω are mixture of ω0 and ω8: = cos8 - sin0 = sin8 + cos0 *Okubo S. // Phys. Rev. 1977. V.16. P.2336

  3. OZI rule • Introducing ideal mixing angle Θi, cosΘi=(2/3)1/2, sinΘi=(1/3)1/2, Θi=35.5° • Θ(mφ,mω,mω8), mω8=m(K*,ρ), Θ=39° • If Z=0, then • R(φ/ω)=tan2(Θ-Θi)f = 4.2·10-3

  4. OZI rule • Okubo: production of ss states in the non-strange hadrons interactions is forbidden •  - production in pp (pp) interaction is possible either due to admixture of light quarks in the  wave function or due to strange quarks admixture in the nucleon.  = -i =3.70

  5. OZI rule predicitions • Universal, does not depend on energy or other properties of the initial state. • Depends on the masses of the meson in the nonet

  6. Comparison with experiment • 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

  7. The OZI rule is always correct, its violation is only apparent Violation indicates on non-trivial physics: • Strange degrees of freedom in the nucleon • Role of gluon degrees of freedom

  8. About hydrogen target • Proton annihilation at rest • Slow antiproton capture on an orbit of ppbar atom with large principal quantum number n~30. • Low pressure gas (~mbar): cascade to lower level, annihilation from P levels with n=2 • Liquid H: Stark mixing between various angular momentum states, annihilation from large n and L=0, i.e. S states.

  9.  • Crystal Barrel, 1995, LQ hydrogen target • p + p →  +  • p + p →  +  • R() = (29497)  10-3 • R()OZI = 4.2  10-3 • L=0, S=0  1S0 spin singlet

  10.  • OBELIX, 1995, LQ, NTP, 5 mb • p + p →  +  • p + p →  +  • R() = (11410)  10-3 • R()OZI = 4.2  10-3 • L=0, S=1  3S1 • spin triplet

  11.  • Different situation for annihilation from S- and P-waves • R() = (12012)  10-3 3S1 • R() < 7.2 10-3 1 P1 • spin triplet – enhanced • spin singlet – suppressed

  12. f2’(1525)/f2(1270) • Tensor mesons: • L=1, S=1, J=2 • f2(1270)  normal qq • f2’(1525)  ss • R(f2’f2) = (4714)  10-3 3S1 • R(f2’f2) = (14920)  10-3 1 P1 • spin triplet – suppressed • spin singlet – enhanced

  13.  • OBELIX, 1995, NTP, 5 mb • p + p →  + + + - • p + p →  + + + - For all events: • R() = (5-6)  10-3 • R()OZI = 4.2  10-3 For events with M=300-500 MeV • R() = (16-30)  10-3

  14. nn • OBELIX, Crystal Barrel • p + d →  + n • p + d →  + n B.Pontecorvo, 1956 One-meson annihilation • R() = (15629)  10-3 • R()OZI = 4.2  10-3

  15. / • If it were a normal quark reaction • ()exp~ 4 b • why is it so large? • () was not measured s p s p s s

  16. Strong violation of the OZI rule was found in • pp • pp, • pp (3S1) • pdn • Does it depend on • spin • orbital angular momentum • momentum transfer • isospin? At LEAR experiemts

  17. Pontecorvo reactions • Largest momentum transfer:q2=-0.782 GeV2/c2 inpdn, compared toq2=-0.360 GeV2/c2 inpp0 • Interesting physics*:two-step modelpp0, nnR() = (15629)  10-3Rth() = (9227)  10-3R() decreases with energy *Kondratyuk L.A., Sapozhnikov M.G., Phys.Lett., 1989, B220, 333. *Kondratyuk L.A. et al., Yad.Fiz., 1998, 61, 1670.

  18. Pontecorvo reactions • Reactions p + d+K0, 0+K0R=Y(K)/Y(K) = 0.920.15two-step model R=0.012 because σ(KNX) > σ(KN X) • Is two-step model correct?

  19. Pontecorvo reactions at PANDA • Energy region never measured before • High statistics expected • Noone really knows why OZI rule is violated in such selective manner • Assuming that OZI rule is precisely correct, we have a hint to non-trivial physics

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