1. Opportunities for Experiments Based on Stored Muon Beams at Fermilab Milorad Popovic Jean-Francois Ostiguy Fermilab August, 2014

2. Motivation Measure neutrino cross-section with better than 10% precision Take advantage of the existing accelerator complex configuration providing beam to the New Muon g-2 Experiment Utilize existing detectors (MicroBooNE, ICARUS) Minimize initial investment. Providing a suitable building to house the detector would be the only investment required Describe possible improvements in collecting and storing muons that would allow cross-section measurements with a precision of a few percent with a modest additional investment. Provide a suitable test facility for future NF August 15, 2014 2

3. The Context We revisit the idea of using the Debuncher as a storage ring for muons the g-2 Experiment expects 6x10-6 stored muons per 8 GeV proton on target August 15, 2014 3

4. g-2 Experiment Booster pulse(5x10 12 Protons@ 8 GeV) is separated in 4 bunches (~100 ns long) in the Recycler The Booster is a 15 Hz machine (not all cycles are used) Target Station is AP0 (Antiproton production target station) and was run with beam power up to 72 kW ( 120 GeV beam from Main Injector) 3.1 GeV/c Pions/Muons are collected using Lithium Lens ( this lens was used for collection of 8.9 GeV/c Antiprotons with ~0.5 Hz) Debuncher is used as delay line for muons (beam is stored for 3 turns). Muons go to g-2 storage ring for experiment. August 15, 2014 4

5. 5 Concept: g-2 Experiment 6x10 -6 stored muons in the Debuncher per 8 GeV proton on target

6. 6 Mu2e g-2 p/m n

7. G4BeamLine simulations of g-2 August 15, 2014 7 In simulation 1.4x10 10 protons on AP0 target  p after Li lens  p at end of transfer line  p after one turn Debuncher

8. g-2 simulations August 15, 2014 8 6x10 -6 stored muons in the Debuncher per one 8 GeV proton on target  m after Li lens  m at the end of transfer line  m after one turn in Debuncher

9. Proton Beam Like for g-2, but with g-2 off August 15, 2014 9 5x10 12 protons in a Booster pulse 3 Hz, 8 GeV Booster Muons are stored for ~100 turns Running time 10 7 Sec (1 year) 100 ton detector, 10 meters downstream from ring ~ 400 CC neutrino events This is for about the cost of moving an existing detector (mBooNE??, 60T) and building a new detector housing (about 3M$)

10. Looking in the near future ( cost~$0.0) August 15, 2014 10 1x10 13 protons from MI (two Booster pulses slip stacked) 1 Hz, 120 GeV MI Muons are stored for ~100 turns Running time 10 7 Sec 100 ton detector, 10 meters downstream from ring ~ 5x400 CC neutrino events

11. Looking Into the Future ( cost~$??) August 15, 2014 11 1x10 13 protons from MI (two Booster pulses, slip stacked) 1 Hz, 120 GeV MI New Li lens r = 2 cm to increase collection of pi’s ( x1.5) Make ring to be racetrack (x 1.5) Running time 10 7 Sec Larger detector, ~500 ton detector( x5) ~ 1.5x1.5x5x5x400 CC neutrino events

12. Questions ? August 15, 2014 12 The End

13. Questions ? August 15, 2014 13

14. SBN Program August 15, 2014 14

15. Experimental CC Inclusive Cross Section Data Reference: PDG Handbook (2013)

16. G-2 simulations Hi Milorad, Please find attached the momentum distributions of pions and muons at three different locations in the g-2 beamline: START - after the Li lens VD5 - at injection into the Debuncher Ring STOP - after one revolution around the Debuncher Ring. For normalization, the number of incident 8-GeV-energy protons in this simulations was 1.47e10. The simulations were conducted using the so-called "default" parameters of the proton beam spot size on the target (sigma_x=sigma_y=0.5 mm) and the Li-lens. With an additional optimization of the proton beam parameters (reducing the spot size on the pion production target) and optimization of the Li-lens position relative to the target at given field strength, the yield of the muons can be increased by may be additional... 30%(?) -- I don't have a precise number for this. The "magic momentum" is 3.094 GeV/c. Hopefully this helps. If you have any questions, please don't hesitate to contact me. Best regards, Volodya August 15, 2014 16