1. /home/vkoch/Desktop/INT2010/parity_ta lk.odp 1 Have we seen Local Parity Violation at RHIC? ● Introduction ● What the present data tell us ● Alternative observable Based on: Adam Bzdak, VK and Jinfeng Liao, PRC81 031901(R) (2010), [arXiv:0912.5050] J. Liao, VK, and Adam Bzdak, in preparation

2. /home/vkoch/Desktop/INT2010/parity_ta lk.odp 2 CPT is in good shape C P T onjecture ress Release hink

3. /home/vkoch/Desktop/INT2010/parity_ta lk.odp 3 J. Liao, BNL workshop, April 2010

4. /home/vkoch/Desktop/INT2010/parity_ta lk.odp 4 The basic observable X (in-plane) Y (out-of-plane) P y (out-of-plane) Charge Separation or Electric Dipole in Pt Space (along out-of-plane direction) Complications: hard to identify direction of magnetic field (reaction plane)P. E-by-E Direction of dipole either parallel OR anti-parallel to magnetic field P x (in-plane) Momentum space Coordinate space B curren t → only variance of parity-odd operator can be observed

5. /home/vkoch/Desktop/INT2010/parity_ta lk.odp 5 The STAR measurement (which everybody discusses)

6. /home/vkoch/Desktop/INT2010/parity_ta lk.odp 6 The STAR measurement (a closer look) P y (out-of- plane) P x (in- plane) + Concentrate on same sign pairs for the moment + Set P y (out-of- plane) P x (in- plane) ++ for both configurations How to distinguish?

7. /home/vkoch/Desktop/INT2010/parity_ta lk.odp 7 The STAR measurement (which not so many discuss) P y (out-of- plane) P x (in- plane) + + P y (out-of- plane) P x (in- plane) ++ Data favor in-plane back-to-back correlation Addto the mix same sign opp. sign.

8. /home/vkoch/Desktop/INT2010/parity_ta lk.odp 8 J. Liao

9. /home/vkoch/Desktop/INT2010/parity_ta lk.odp 9 The bottom line

10. /home/vkoch/Desktop/INT2010/parity_ta lk.odp 10 Using simple math STAR measures for same sign pairs in Au+Au: Therefore: No out-of-plane correlation for same charge pairs Opposite charge: in- plane out-of- plane Same Charge opp. Charge

11. /home/vkoch/Desktop/INT2010/parity_ta lk.odp 11 Saving the chiral magnetic effect...

12. /home/vkoch/Desktop/INT2010/parity_ta lk.odp 12 The argument in the STAR papers: B out, B in = Background (in and out of plane) P = Parity violating signal Thus: The data show Thus existence of CME would require: ● “Juuuuust right scenario” a.k.a fine tuning !!! ● We need to understand the background ● We need differential information on

13. /home/vkoch/Desktop/INT2010/parity_ta lk.odp 13 Do we understand the background NO!

14. /home/vkoch/Desktop/INT2010/parity_ta lk.odp 14 How realistic is the assumption ? Two particle density: Prominent example: HBT with respect to the reaction plane Implies: “background” correlations are independent of reaction plane Reaction plane dependence always enters via v 2 ! P t – and eta dependence of v 2 needs to be taken into account Sources discussed in context of CME: Clusters (STAR, F. Wang), Resonances (STAR),.Anomaly (Asakawa et al)...

15. /home/vkoch/Desktop/INT2010/parity_ta lk.odp 15 P t -dependence Correlated pairs are only moderately harder than thermal pairs

16. /home/vkoch/Desktop/INT2010/parity_ta lk.odp 16 Alternative observable Quadrupol e moment Reaction plane angle Charged dipole moment Charged dipole angle

17. /home/vkoch/Desktop/INT2010/parity_ta lk.odp 17 Extract dipole moment and angle

18. /home/vkoch/Desktop/INT2010/parity_ta lk.odp 18 J. Liao

19. /home/vkoch/Desktop/INT2010/parity_ta lk.odp 19 J. Liao

20. /home/vkoch/Desktop/INT2010/parity_ta lk.odp 20 Correlations can lead to similar dipole angel; but reduce magnitude

21. /home/vkoch/Desktop/INT2010/parity_ta lk.odp 21 Summary P y (out-of- plane) P x (in- plane) ++ ● Data favor in-plane back-to-back correlation for same charge – CME predicts out of plane ● Presence of CME requires fine-tunining: Background = - CME ? ● Need differential information on – Be aware that p t - and eta dependencemay be differernt ● Alternative observable: measure charge dipole (orientation and magnitude) ● How about proton-proton????

22. /home/vkoch/Desktop/INT2010/parity_ta lk.odp 22 Conclusion NO definitive evidence for local parity violation! Yet !?