The Steering Group and mu2e

1
The Steering Group and mu2e

• Eric Prebys

2
General

• The Fermilab Steering group has presented its
  report
• Priorities (post-collider)
• LHC Support
• ILC RD
• RD for a new facility to enhance the labs
  intensity frontier capabilities at 8, 120, and
  800 GeV, primarily for neutrino physics
• An 8 GeV linear accelerator based on ILC
  technology, currently referred to as Project X
• Could be running as early as 2015
• Consider other opportunities to exploit existing
  facilities in the near term (no priorities
  given)
• Mu2e
• Neutral K-gtpnn (KOPIO) at 8 GeV (uses Debuncher)
• Charged K-gtpnn (KTeV-II) at 120 GeV (uses TeV as
  stretcher)
• n scattering at 800 GeV (NUSONG), resurrent TeV
  fixed target
• Physics with antiprotons
• Possibly SNuMI (if ILC only slightly delayed
  and/or built offshore)
• Alternative to Project X !!

Main thrust of report
3
Specific Mentions of mu2e (talking points)

• Discussed under 3.2 (Precision Physics)
• An intense 8 GeV proton beam and the Accumulator
  and Debuncher rings, available after the end of
  antiproton production for the Tevatron Collider
  program, would make possible an LFV search
  experiment that would make, by far, the single
  most sensitive search for any LFV process.
• In appendix D (under Precision Physics
  Experiments with Muons)
• The MECO design has been reviewed for cost and
  technical feasibility in detail, and a new
  experiment based on MECO could be developed into
  a reviewable project at Fermilab with about one
  year of effort. Physics results at sensitivity
  below 10-16 would follow 4-5 years of
  construction and 2-3 years of running. Upgrades
  to use a more intense beam following the SNuMI or
  Project-X construction would be studied and then
  implemented following the first physics running
  period.

4
Proton Driver vs Project X

• Proton Driver
• 8 GeV H- linac feeding directly into Main
  Injector
• Tailored for 2MW at 120 GeV
• 1.5E14 protons per pulse
• High energy end uses beta1 ILC cavities
• .5-2MW total 8 GeV proton capacity
• Problems
• Integrated charge/pulse about 3 times higher than
  ILC -gt very different beast.
• Excess proton capacity (long pulses of H- ions)
  difficult to transport and use.
• Project X
• Highest 6 GeV exactly like the ILC
• 9 mA x 1ms
• 5 Hz
• Strip/inject into Recycler
• Inject 3 pulses worth (1.7E14 protons) into the
  Main Injector ever 1.4 second cycle
• Leaves up to 4 pulses (200 kW) for other uses
• This batches are stripped and stored in the
  Recycler, where they can be rebunched as needed

LAB
2015
5
Project X and mu2e

• Availability of up to four linac pulses _at_50kW
  each
• Compare to max 35kW with base line scheme
• Probably cannot slow spill from Recycler
• Cannot design around Project X, even if we wanted
  to (which we dont !!!)

• Must transfer batches to Accumulator and handle
  more or less as we handle Booster batches
• Increased intensity has implications for target
  and detector

• Given the current enthusiasm for Project X, we
  cant ignore it, but it shouldnt become too much
  of a distraction
• Boiler plate in LOI
• More detailed discussion of detector and target
  upgrades in proposal

6
Important Mistakes in Report (wrt mu2e)

• Some confusion about 8 GeV proton availability in
  NOvA era
• Section 4.3 incorrectly states that a program
  protons debunched and extracted proton beam would
  take protons away from the 120 GeV program. In
  fact, that would only be true in the SNuMI
  scenario .
• First paragraph of the "Upgrade to the Fermilab
  Proton Facility" section (p. 32) incorrectly
  states that an 8 GeV physics program cannot be
  supported without compromising the NOvA physics
  program. Again, this will not be true except
  under the SNuMI scenario.
• Discussion of neutral K-gtpnn experiment (KOPIO)
  very confusing
• Neglects to mention that this experiment would
  also require the Debuncher
• Bundling it with KTeV-II in Appendix D gives
  casual reader the impression it somehow uses the
  TeV stretcher

communicated to Young-Kee Kim
7
Significant Omissions in Report

• Report generally states the impact of the near
  term proposals on NOvA, but make no mention
  whatsoever about how they compete with each
  other, specifically
• Mu2e and KOPIO would not affect NOvA, but would
  have to share protons and the Debuncher with each
  other (a la RSVP)
• Either of these and/or SNuMI are completely
  incompatible with continued operation of the
  antiproton source.
• NuSONG (800 GeV protons) and KTeV-II/SY120
  compete directly with each other for use of the
  the Tevatrons, and make some small impact on
  NOvA, but do not compete directly with Mu2e
  and/or KOPIO