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MEG Experiment at PSI now constructing an experiment to measure the related

Jim Miller * Boston University.

crispin-holley
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MEG Experiment at PSI now constructing an experiment to measure the related

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  1. Jim Miller* Boston University Muon to Electron Conversion- Mu2eNeutrino-less, coherent conversion in the field of a nucleusAn example of Charged Lepton Flavor Violation (CLFV)Status: Rme= G(m- A->e-A)/G(m-A->nmA)<7x10-13(SINDRUM II)Proposed for Fermilab (or JPARC, or?):Rme<10-16 • SM prediction, from neutrino mixing, is far below experimental accessibility • --> no SM background • Discovery of CLFV: unambiguous evidence of physics beyond SM • Current limits on CLFV already provide severe constraints on models beyond SM • CLFV processes occur in nearly all scenarios for physics beyond the SM • In many cases the physics reach goes well beyond that of direct searches • MEG Experiment at PSI now constructing an experiment to measure the related • reaction: m->eg, with the goal BR=10-13. • Mu2e(at 10-16) will be ~ 3x more sensitive than MEG (at 10-13) for photon mediated • processes, and ~1000x more sensitive for most other types of non-SM contributions. Leptoquarks: ML=3000 (lmdled)1/2 TeV/c2 SUSY: predictions at 10-15 • mA->eA has a tremendous reach to Lc~3000 TeV (for Rme~10-16) and has the possibility to go further ( Rme~10-18 to ??) with upgrades in beam and detector • If m->eg is observed, then mA->eA is complementary, and is unique in its ability to help sort out the source of CLFV through inteference effects in different targets • If LHC sees SUSY, mA->eA is needed to sort out LFV MZ’=3000 TeV/c2 Compositeness: LC=3000 TeV • Representing the Mu2e Steering Group: Boston U, BNL, Fermilab, NYU, UC-Berkeley, UC-Irvine, Osaka, Syracuse, UMASS, UVA

  2. Experimental Approach • Stop m-in matter, form atom in 1s state in less than10-16 seconds • 3 main reactions: capture, m-A->nmA’, decay, m-->e-nn, conversion, m-A->e-A’ Case of aluminum: (nuclear capture rate) ~ (decay rate), lifetime ~0.9 ms • Conversion process is special: mA eA has big experimental advantages • monenergetic electron (105 MeV): energy far from most background • high rates are possible- no coincidence is required (contrast with m->eg) • Use pulsed muon beam, spacing ~1-2 ms, dictated by muonic atom lifetime • Toreach goal G(m- A->e-A) / G(m-A->nmA) < 10-16 need ~4x1020 protons, 1018 muons, ~2-4 years running with 10-20% of beam at FNAL • Following MECO: Develop high-flux muon source and a special detector arrangement to minimize background • Physics case, technical feasibility, design have successfully passed many reviews. • Conceptual designs and intial costing for MECO are done • Good beam concept at FNAL has been identified with minimal disruption of the planned neutrino program • Recent meeting at FNAL drew ~50 scientists. Physics case and interest is strong. • Not asking nuclear physics to support entire experiment: several nuclear groups have shown interest in the project- need nuclear support for these groups • Fermilab director encourages LOI in 2007, detailed design work on proton source • Ideas for a next version which could reach Rme~ 10-18 or betterwith higher muon fluxes- JPARC??

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  4. Muon to Electron ConversionAn example of Charged Lepton Flavor Violation (CLFV)Status:Rme= G(m- A->e-A)/G(m-A->nmA)<7x10-13Proposed for Fermilab (or JPARC, or?):Rme<10-16 • SM prediction, from neutrino mixing, is far below experimental accessibility • --> no SM background • Discovery of CLFV: unambiguous evidence of physics beyond SM • Current limits on CLFV already provide severe constraints on models beyond SM • CLFV processes occur in nearly all scenarios for physics beyond the SM • Related reaction: m->eg, BR~300-400 times more sensitive than mA->eA for • photon-mediated CLFV, but same sensitivity for most other intermediate states. • MEG (PSI) plans m->eg measurement to ~10-13. Phase II MEG: 2x10-14? • May be m->eg experimental limit. -> at 10-16 mA->eA is 3x more sensitive for photon- • mediated, 1000x for most other intermediate states • If MEG sees m->eg, then mA->eA unique in its ability to help sort out source of CLFV by changing • target nuclei and seeing interference • If LHC sees SUSY, mA->eA is needed to sort out LFV

  5. Leptoquarks: ML=3000 (lmdled)1/2 TeV/c2 SUSY: predictions at 10-15 Compositeness: LC=3000 TeV MZ’=3000 TeV/c2

  6. Jim Miller* Boston University Muon to Electron Conversion- Mu2eNeutrino-less, coherent conversion in the field of a nucleusAn example of Charged Lepton Flavor Violation (CLFV)Status: Rme= G(m- A->e-A)/G(m-A->nmA)<7x10-13(SINDRUM II)Proposed for Fermilab (or JPARC, or?):Rme<10-16 • SM prediction, from neutrino mixing, is far below experimental accessibility • --> no SM background • Discovery of CLFV: unambiguous evidence of physics beyond SM • Current limits on CLFV already provide severe constraints on models beyond SM • CLFV processes occur in nearly all scenarios for physics beyond the SM • In some cases the physics reach goes well beyond the reach of direct searches • Related reaction: m->eg, BR~300-400 times more sensitive than mA->eA for • photon-mediated CLFV, but same sensitivity for most other intermediate states. • MEG (PSI) plans m->eg measurement to ~10-13. Phase II MEG: ~2x10-14? • (This may be the best that m->eg experiment can ever do.) mA->eA at 10-16is • comparable to phase II for photon- mediated, 1000x for most other intermediate states Leptoquarks: ML=3000 (lmdled)1/2 TeV/c2 SUSY: predictions at 10-15 • If MEG sees m->eg, then mA->eA is complementary and unique in its ability to help sort out source of CLFV by changing target nuclei and seeing interference effects • If MEG does not see CLFV, then power of mA->eA needed to reach lc~3000 TeV (for Rme~10-16) and beyond(for Rme~10-18 to ??) • If LHC sees SUSY, mA->eA is needed to sort out LFV MZ’=3000 TeV/c2 Compositeness: LC=3000 TeV • Representing the Mu2e Steering Group: Boston U, BNL, Fermilab, NYU, UC-Berkeley, UC-Irvine, Osaka, Syracuse, UMASS, UVA

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