1 / 17

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

judith
Download Presentation

Oleg Teryaev BLTP, JINR

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  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

More Related