Kara Hoffman

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					          Kara Hoffman
         The University of Chicago
            Enrico Fermi Institute

On behalf of the Muon Collaboration
Conventional Beams
                                                           measure


                                                           small ne contamination gives
                                                           same final state signatures


     Wouldn’t it be great if:
     •we had a high intensity, collimated neutrino beam of known flavor composition?
     •we had a clean source of electron neutrinos?
     •a reaction could be compared to it’s charge conjugate?

Muon Beams

                                                               measure (primarily)

                                                           unambiguous if you can
                                                           identify both lepton charge
                                                           and flavor
        2         2
For |Dm32| >> |Dm12|
and neglecting dCP:




  will be known to +/- 10%?
Could be built in stages, with interesting physics
 Could be built in stages, with interesting physics                      Proton driver
addressed at each stage
 addressed at each stage                                             neutrino oscillations



  Intense cold muon source
  muon magnetic moment
  muonium-antimuonium
  muon spin rotations rare
  decays
                                                       Neutrino Factory
                                                                     sin q13 < 10 -4
                                                                 2
                                                      sign of Dm 32 for sin q13 < 10 - 4
                                                                                    d CP

   Bowtie offers                                                Future Muon Collider
  opportunity to
 send beams to                                                Higgs pole physics energy
  different sites                                                       frontier machine
            Paper designs exist, and real experiments are being built to test
                   new technologies required (i.e. ionization cooling)
                                                                               2
                                                de ^ , N e dE b x ( .6MeV/c )
                                                                  13
                                                     = - 2N    +
                                                  dz    b E dz   2 b 3 Emm LR

                                                                   spectrometer
                                                                   selonoid
                                                                          fiber tracker
                                                                            particle ID
incoming
muon beam                         rf cavities
                       ionizing
                       material




    Muon Test Area is being built to test components…
   Muon Test Area at
   Fermilab under
   construction
Conceptual advances since Study II
              Ring Coolers                                                   Gas filled rf cavities

                                        Suppress
                                        breakdown in
                                        high gradient
                                        cavities while
                                        cooling beam

                                                            Paschen’s Law the breakdown voltage for
                                                             Paschen’s Law the breakdown voltage for
                                                                Gradient between for GH2 in
                                                                            Pressure           77K
                                                             aadischarge vsbetweenelectrodesat ingases is aa
                                                                discharge            electrodes gases is
                                                           function of the product of pressure and distance.
                                                            function of the product of pressure and distance.
                                                           60
                                                           50       H2 gas @77K
provides same transverse
                                         Gradient (MV/m)   40
                                                                    805 MHz
cooling as sFOFO linear
channel considered in                                      30
                                                                                         Muon Collaboration
neutrino factory Study II                                  20                            results (2003)
                                                           10                            Felici (1948)
  Both could offer better performance
  Both could offer better performance                      0
    and/or significant cost savings
     and/or significant cost savings                            0       50     100       150      200     250
                                                                              Pressure   (PSIA)
                                  Important if LSND
                                  is confirmed




For 50 kiloton detector
 For 50 kiloton detector




             E3
              m
N events   µ    N M (detector in kilotons )
             L2 m
                                              Mass Hierarchy
                                          Normal?           Inverted?



          +                 -
      m                 m
                    2
      2           dm<0
    dm<0
m

                                            Matter Effect
              +             -     has different effects on electron
          m         2
                        m           neutrinos and antineutrinos
          2
                                                         sin 2 2q
     dm>0         dm>0            2   m
                                sin 2q =                            2
                                           Ê 2 2GF N e En          ˆ
                                           Á
                                           Á              - cos 2q ˜ + sin 2 2q
                                                                   ˜
                                           Ë    dm 2               ¯


                                                 enhances dm2 > 0
                                                 supresses dm2 < 0
Need a long baseline and both m+ and m- beams
Measuring CP violating phase: d



                                  Possible if:
                                       Dm122, s12 large enough (LMA)
                                       q13 not too small
As we have seen, oscillation probabilities depend on several parameters
 As we have seen, oscillation probabilities depend on several parameters
 simultaneously (i.e. d, 13). Multiple independent measurements (different L, E,
simultaneously (i.e. d, qq13). Multiple independent measurements (different L, E,
channels) needed to resolve resulting degenerate solutions.
 channels) needed to resolve resulting degenerate solutions.
                                             real
                                             solution
                                                         golden
                                                        channel
Degeneracies we
                                                                        high statistics,
worry about:
                                                                      low background
                                                         silver
• d, q13
                                                         channel
• sign   of Dm13
• (q23, p-q23) – goes
away for current                                                      difficult to detect
best fit value q23=p/2                                               emulsion detector
                                                                                 needed
                                                                   also needed to place
                                                              limits on sterile neutrinos
  Neutrino Factories complement present and near term experiments

   •Measurements of oscillation parameters from other experiments will provide valuable input in
   choice of baseline
   •Accelerator (i. e. proton driver) and detector technologies developed will also be invaluable
   •Combinations of experiments may be helpful in resolving degeneracies
Neutrino Factories provide clean, high intensity beams which may be necessary in
probing some areas of parameter space

   • dCP if sin q13 is small
   • measurement of small q13
   • combination of m+ and m- beams definitively measures mass hierarchy
Staged program provides a unique tools for both oscillation and non-oscillation
physics
   • precision measurement of neutrino oscillation parameters, cold muon physics,
   Higgs pole physics
R&D and conceptual advances have the potential to decrease the cost and increase
the performance of the design
   • “engineering” experiments are going forward
Extra Plots