Mu2e, August 15, 2007 E Prebys 1 The Steering Group and mu2e Eric Prebys

Mu2e, August 15, 2007 E Prebys 2 General The Fermilab Steering group has presented its report Priorities (post-collider):  LHC Support  ILC R&D  R&D for a new facility to enhance the lab’s “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->  (KOPIO) at 8 GeV (uses Debuncher) Charged K->  (KTeV-II) at 120 GeV (uses TeV as stretcher)  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

Mu2e, August 15, 2007 E Prebys 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 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.

Mu2e, August 15, 2007 E Prebys 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 beta=1 ILC cavities .5-2MW total 8 GeV proton capacity  Problems: Integrated charge/pulse about 3 times higher than ILC -> 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

Mu2e, August 15, 2007 E Prebys 5 Project X and mu2e Availability of up to four linac 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 don’t !!!) Given the current enthusiasm for Project X, we can’t ignore it, but it shouldn’t become too much of a distraction:  Boiler plate in LOI  More detailed discussion of detector and target upgrades in proposal Must transfer batches to Accumulator and handle more or less as we handle Booster batches  Increased intensity has implications for target and detector

Mu2e, August 15, 2007 E Prebys 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->  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

Mu2e, August 15, 2007 E Prebys 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