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New Ideas for a Super B Factory

New Ideas for a Super B Factory. Steve Playfer University of Edinburgh ILC Forum, Cosener’s House, May 2006. /fb. The Current B factories. BELLE. BaBar. 10 9 B meson pairs in each experiment by Autumn 2008 (1/ab). Current CKM Status.

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New Ideas for a Super B Factory

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  1. New Ideas for a Super B Factory Steve Playfer University of Edinburgh ILC Forum, Cosener’s House, May 2006

  2. /fb The Current B factories BELLE BaBar 109 B meson pairs in each experiment by Autumn 2008 (1/ab)

  3. Current CKM Status Unitarity Triangle angles and sides are all measured: Vtd, Vcb, Vub,  by BaBar and BELLE Vts by CDF and D0

  4. The Standard Model triumphs again in the Heavy Flavour sector • So why do we want to produce yet more B mesons? • …and what has it got to do with a workshop on the International Linear Collider?

  5. We don’t understand Flavour Physics! • Why are there three generations? • Why are the lepton and quark couplings different? • Why are the Standard Model CKM parameters what they are? • What is the flavour structure of new Physics at the Electroweak scale? • Most studies assume Minimal Flavour Violation, but this has to be checked!

  6. Physics Topics at SuperB • Improve CKM constraints • angles  are statistics limited • Vub can also be improved • Discrepancies in rare bs transitions? • sin2 in bs penguins • AFB in bsl+l- • Forbidden processes •  • D0 mixing and CP Violation

  7. Comparison of Sin2 spectator diagrams penguin diagrams s b u,c,t _ d _ d Penguin results are consistently lower (but never by more than 2) “Naïve average” not reliable (different theory predictions for different decay modes)

  8. AFB in BK*l+l- BaBar Belle Low q2: AFB > 0.19 (95% C.L.) Standard Model: 0.03 Low q2: AFB > 0 Standard Model fit shown

  9. Recent activity • CERN workshops on Flavour in the LHC era (November, February, May) • Frascati workshops on Super B (November, March) • Daresbury Meeting (April) Things are evolving rapidly. No baseline design. No version control. I will do my best to summarize!

  10. LHCb and SuperB are complementary! , c and decays with only at SuperB?

  11. Super KEK-B Higher beam currents More RF cavities Smaller * and crab crossing Luminosity 2-5 x 1035 Integrate 20-50/ab by 2020 3-6 x 1010 B meson pairs Proposal submitted to KEK by BELLE last year.

  12. Linear Collider B factory • “An electron-positron linear collider as a B-anti B Meson factory” (Amaldi & Coignet 1986) • Idea resurrected at Hawaii Super B workshop (Pantaleo Raimondi, April 2005) • “Super B: a linear high luminosity B factory” (J.Albert et al, hep-physics/0512235) Benefits from all the Linear Collider R&D that has been going on in the last 20 years. Looks feasible to get luminosity of 1-2 x 1036 at Y(4S)

  13. 1.5 GeV Linac 2 GeV Linac 1.5 GeV Linac Damping Rings 2 GeV e- Gun e+ Gun Linac Linac First Linear Super B scheme with accelerationand energy recovery (to reduce power) 2 GeV e+ injection 4 GeV e- 2GeV e+ DR e- Gun IP • Use Superconducting Linacs to recover energy • Use low energy damping rings to reduce synchrotron radiation • Maybe no e- damping ring • Use bunch compression and final focus a la ILC • Energy and asymmetry tunable • Polarized beams possible 5GeV e+ SC Linac 4GeV e- SC Linac 7GeV e+ e- Dump

  14. Second design of Super B ILC damping rings ILC final focus ILC bunch compressor Colliding every 50 turns Acceleration optional Crossing angle optional Compressor Decompressor FF IP FF Optional Acceleration and deceleration Optional Acceleration and deceleration Compressor DeCompressor Latest design has no acceleration and a crossing angle

  15. Parameters of Super-B Designs John Seeman, FPCP 2006

  16. Single Pass Linear Collider Scheme • Collide each bunch once very hard and then recycle it • Vertical emittance blow up x300 • Use very small beta functions to achieve high luminosity • Re-inject disrupted bunch into damping ring for ~6 damping times • Need very short damping time (~1ms) • High power requirement for damping ring • Collision frequency 120Hz x 10000bunches is ~1MHz

  17. Single pass Super B collider Nbunches=12000 in two 6km damping rings E(e+) = 7GeV E(e-) = 4 GeV sx=30mm sy=10nm sz=100mm sz=4mm in DR se=100MeV se/e=2*10-2se/e=5*10-4 in DR se_Luminosity=7MeV ex=0.8nm ex_norm=8mm ey=0.002nm ey_norm=20pm ez=2.0mm Stored time between collision = 1msec = 50turns Luminosity (50 turns) = 0.9*1036 Luminosity better with single turn = 1.5*1036

  18. Colliding every turn with Bunch Compression • Install ILC like final focus in the damping rings • Room for long enough straight section or use an arc inside the ring • Choose a much lower disruption to avoid blowing up the bunch too much • Use bunch compression/decompression to shorten bunches for the final focus • Use monochromator scheme to compensate the energy spread at the IP to match the Y(4S) resonance

  19. Comparison of Rings (Andy Wolski)

  20. Contradictory requirements at IP • Disruption • Luminosity • Energy spread - important at Y(4S)! Decrease number of bunches Decrease bunch length Increase spot size Increase number of bunches Decrease spot size Decrease number of bunches Increase bunch length Increase spot size

  21. Most recent Ideas • Optimum is to collide every turn • Use bunch compression/decompression • Use double rings • First ring for damping • Second ring for compression and final focus • Use crossing angle (2x25mrad) • Compensate disruption at IP using a travelling focus Some of these ideas are also relevant to ILC Some tests are planned at Frascati (DAFNE)

  22. Large Crossing Angle Scheme • Collide with 2x25mrad crossing angle • Only small longitudinal part of bunch gives luminosity, but various solutions possible: • Compensate with very small vertical beta function using an ILC type final focus • Use travelling focus in horizontal plane • Crab cavities • In this scheme the disruption is small and strong damping is not needed.

  23. SYNERGY BETWEEN ILC and SuperB? “Synergy …is frequently described as the 2 + 2 = 5 effect to denote the fact that the combined performance is greater than the sum of its parts.” Corporate Strategy, H.I.Ansoff (1965)

  24. Synergy between PEP-II and KEK-B

  25. Synergy between SuperB and ILCshould also be a win/win situation • The SuperB factory will be a better machine because of the ILC AND • The Linear Collider will be a better machine because of SuperB If only the first of these statements is true the SuperB factory is parasitic to the ILC The second statement is what sells SuperB to the ILC community!

  26. Damping RingsILC 5 GeV SuperB 4-7 GeV Electron rings almost identical Positron rings somewhat different Same lattice Similar damping times Different sizes (3km - 6km) Different currents Different RF frequencies Similar bunch patterns Final focus inserted into rings (SuperB)

  27. Final Focus Same bunch compression Similar IP geometry Different beam energies! CM energy resolution (SuperB) Different sources of backgrounds Different crossing angles (2-25 mrad) Different bunch trains (ILC) Different disruption parameters Different currents Final focus inserted into rings (SuperB)

  28. Comments on Timescales • ILC construction assumed to begin somewhere between 2010 and 2020 • SuperB construction assumed to begin somewhere between 2010 and 2014 • They may be operating in sequence and/or in parallel: • SuperB may precede the ILC • SuperB is unlikely to be after ILC Does it help more to have SuperB before ILC, or is it the same if they are in parallel?

  29. Comments on Sites • SuperB and ILC at different sites • Large difference in location of damping rings? • Differences in detailed design parameters • Both need the full currents of the damping rings for luminosity • Frascati’s idea, and Italy is keen to host. • Need new tunnel • There are existing 2-6 km rings • PEP, KEK, Tevatron, HERA • ILC have plans for new damping ring test facilities

  30. Searching for New Physics • Method I - Go to higher energies (LHC, ILC) • Produce new particles. • Measure masses and main decay modes. • Method II - Go to higher precision (LEP, B, ILC) • Produce lots of known particles. • Make accurate measurements of couplings • Measure rare decays. • Method III - Look for “forbidden” things ( …) • Neutrino masses, mixing and CP violation. • Lepton flavour violation. • Electric dipole moments. To get a complete picture we should do all of these

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