MICE: The First Cooling Frontier

1. MICE: The First Cooling Frontier V. Blackmore 18th May, 2010

2. Summary • Physics at a NF • Benefits of a Muon Collider • Creating and Cooling Muons • MICE • Future 2/20

3. Physics at a NF • Neutrino flavours are a superposition of mass eigenstates: • Measure sin22q13, even if q13 is small. • Determine mass hierarchy. • Search for CP violation in the lepton sector. m3 m2 m1 or 3/20

4. NF Physics Sensitivity • Search for “wrong sign” muons: • An initial beam of m+, produces 50% ne and 50% nm • Clean experimental signature and extremely low backgrounds • Can measure values of sin22q13 down to O(10-4) No oscillation With oscillation nm m- 4/20 Hadron Shower N Figure from FNAL-TM-2259

5. NeutrinoFactory MuonCollider NF and Muon Collider Components • Bright, intense neutrino beams and step towards a muon collider… 5/20 Image from M. Zisman, Muon Collider Physics Workshop 2009

6. Muons suffer little synchrotron radiation loss. Smaller energy spread at Interaction Point for precision energy scans RF (expensive!) used efficiently, giving a compact footprint. ratio makes the Higgs coupling 40’000 larger. Benefits of a Muon Collider 6/20 Image from M. Zisman, Muon Collider Physics Workshop 2009

7. m m m m m m Creating Muons nm nm ne m p To Accelerator p p p p p nm Target Decay Channel nm Resulting muon beam has a large spread in energy and momentum. This is difficult to accelerate! (Plus, they don’t live long...) 7/20

8. Liouville’s Theorem Emittance = area of phase space ellipse 8/20

9. Liouville’s Theorem Emittance = constant “The particle density in phase space is constant unless acted on by non-conservative force.” 9/20

10. Cooling Cooling is a reduction in emittance. We must violateLiouville’s Theorem! 10/20 ...not that it hasn’t been done before.

11. Transverse Pickup Amplifier Transverse Kicker Traditional Cooling Electrons in a damping ring Muons are too heavy. Stochastic cooling Ions cooled by pre-cooled electron beam cooling 11/20 Muon is short lived.

12. RF RF Ionisation Cooling Small(er) emittance Large emittance Absorber Absorber 12/20

13. MuonIonisation Cooling Experiment • Aim: • Build a section of cooling channel • Master engineering and operation • Measure cooling with high precision • Experience feeds back into NF and collider design 13/20

14. MICE Hall at RAL 14/20

15. COOLING vs. HEATING • Cooling is balanced by multiple Coulomb scattering • Equilibrium emittance = minimum emittance a material can provide: • Low b^ (strong focusing), large X0 and dE/dz (H2 is best) Cooling Heating 15/20

16. The Cooling Channel Liquid Hydrogen Absorber RF Focus Coils 16/20

17. Muons produced with large emittance Need to contain beam and provide tight focussing at absorbers SFoFo lattice Magnetic field reverses at absorbers to prevent build-up of canonical angular momentum. MICE Magnetic Field matched in tracker babs= 42cm 17/20 Image from M. Rayner, MICE Collaboration Meeting, March 2010

18. Images from M. Rayner, MICE Collaboration Meeting, March 2010 The current MICE muon beam. Characterised using the TOFs by M. Rayner (Oxford) Preliminary! THE REAL MICE BEAM 18/20 3s fit 3s fit

19. Images from M. Rayner, MICE Collaboration Meeting, March 2010 Absorber Absorber Absorber RF Diffuser RF Real beam simulations Beam inflated by diffuser Emittance reduced in absorbers. Energy replaced by RF Preliminary! Cooling in MICE MICE should work! TOF 19/20

20. The Future Image from B. Palmer, Muon Collider Physics Workshop 2009 20/20

21. The Future 20/20

23. EXTRA

25. Liouville’s Theorem

26. Neutrino Oscillations • Suppose neutrinos {n1, n2, n3} have different masses {m1, m2, m3}. Each neutrino flavour is a mix of these. • E.g. in a two flavour system: • Probability for a nm to oscillate to ne is: 4/22