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Oleg Teryaev BLTP, JINR

Oleg Teryaev BLTP, JINR. Chiral magnetic effect for heavy and strange quarks Physics at NICA ( iVth roundtable workshop) Dubna , JINR, September 9, 2009. Outline. Strange quarks as heavy ones: Vacuum and (multiscale) hadrons Axial anomaly and Heavy quarks polarization in nucleon

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Oleg Teryaev BLTP, JINR

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  1. Oleg Teryaev BLTP, JINR Chiral magnetic effect for heavy and strange quarksPhysics at NICA(iVth roundtable workshop)Dubna, JINR, September 9, 2009

  2. Outline • Strange quarks as heavy ones: Vacuum and (multiscale) hadrons • Axial anomaly and Heavy quarks polarization in nucleon • Chiral magnetic effect for strangeness in Heavy Ions collisions • Transition to massless quarks • Local C, P and CP violation: signals in decays • Conclusions

  3. Can s REALLY be heavy?! In nucleon (no valence “heavy” quarks) rather than in vacuum - may be considered heavy in comparison to small genuine higher twist – multiscale nucleon picture In vacuum Strange quark mass close to matching scale of heavy and light quarks – relation between quark and gluon vacuum condensates (cancellation of classical and quantum symmetry breaking – for trace anomaly). The same – for axial anomaly

  4. Cancellation of explicit and anomalous symmetry breaking for Massive quarks • One way of calculation – finite limit of regulator fermion contribution (to TRIANGLE diagram) in the infinite mass limit • The same (up to a sign) as contribution of REAL quarks • For HEAVY quarks – cancellation! • Anomaly – violates classical symmetry for massless quarks but restores it for heavy quarks

  5. Heavy quarks polarisation Non-complete cancellation of mass and anomaly terms (97) Gluons correlation with nucleon spin – twist 4 operator NOT directly related to twist 2 gluons helicity BUT related by QCD EOM to singlet twist 4 correction (colour polarisability) f2 to g1 “Anomaly mediated” polarisation of heavy quarks

  6. Numerics Small (intrinsic) charm polarisation Consider STRANGE as heavy! – CURRENT strange mass squared is ~100 times smaller – -5% - reasonable compatibility to the data! (But problem with DIS and SIDIS) Current data on f2 – somewhat larger

  7. Comparison : Gluon Anomaly for massless and massive quarks • Mass independent • Massless (Efremov, OT ’88) – naturally (but NOT uniquely) interpreted as (on-shell) gluon circular polarization • Small gluon polarization – no anomaly?! • Massive quarks – acquire “anomaly polarization” • May be interpreted as a kind of circular polarization of OFF-SHELL (CS projection -> GI) gluons • Very small numerically • Small strange mass – partially compensates this smallness and leads to % effect

  8. Charm/Strangeness universality • Universal behaviour of heavy quarks distributions - from non-local (C-even) operators • c(x)/s(x) = (ms /mc)2 ~ 0.01 • Delta c(x)/Delta s(x)= (ms /mc)2 ~ 0.01 • Delta c(x)/c(x) = Delta s(x)/s(x) • Experimental tests – comparison of strange/charmed hadrons asymmetries

  9. Heavy unpolarized Strangeness: vector current • Follows from Heisenberg-Euler effective lagrangian (confirmed: A. Moiseeva, M. Polyakov, Y. Silverding) • FFFF -> (Color = combinatoric) FGGG -> Describes strangeness contribution to nucleon magnetic moment and pion mean square radius • FFFF->FFGG -> perturbative description of chiral magnetic effect for heavy (strange) quarks in Heavy Ion collisions – induced current of strange quarks

  10. Chiral magnetic effect for (heavy) strange quarks • Effective Lagrangian • Current and charge density from c-term (multiscale medium!) • Light quarks -> matching with D. Kharzeev et al’ -> correlation of density of electric charge with a gradient of topological one (Lattice ?)

  11. Properties of perturbative charge separation • Current carriers are obvious - strange quarks -> matching -> light quarks? • NO obvious relation to chirality – contribution to axial current starts from pentagon diagram • Effect for strange quarks is of the same order as for the light ones if topological charge is localized on the distances ~ 1/ms , strongly (4th power!) depends on the numerical factor • Universality of strange and charm quarks separation - charm separation suppressed as (ms /mc)4 ~ 0.0001 (But charm production is also suppressed – relative may be comparable at moderate energies – NICA?)

  12. Other signals for local symmetry violations? • Some other signals (CP-violating decays?? – question of V.I. Zakharov) • Topological charge: P-Violated, C-conserved; not sufficient for forbidden K decays • Other possibility – C - violating decays due to chemical potential

  13. Forbidden decays in vacuum – allowed in medium • C-violation -> (Weldon ’92) • (OT’96; Radzhabov, Volkov, Yudichev ’05,06 - NJL) • However: Short time of medium existence – EM part should be outside!)

  14. Two-stage forbidden decays - I

  15. Two-stage forbidden decays -II

  16. Relating forbidden and allowed decays • In the case of complete mass degeneracy (OT’05, unpublished): • Tests and corrections – Bannikov,OT, in progress

  17. Conclusions • Strange quarks may be considered as heavy sometimes • Chiral magnetic effect for stange quarks – straightforward modification of Heisenberg-Euler lagrangian • Strange-light transition; strange mass against topological charge correlation length • Multiscale hadron/medium • Local C-violation in medium – decays forbidden in vacuum with predictable ratios

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