Expression of Interest for the Evolution of Mu2e – Mu2e-II D. Glenzinski (Fermilab) On behalf of Mu2e-II Signatories
Mu Mu2e-II II Defin finit itio ion • An upgrade to current Mu2e construction that − Uses ~100 kW of PIP-II protons − Leverages as much of Mu2e investment as reasonably possible − Achieves an order of magnitude improvement in sensitivity (ie. probes R µ e ~ 10 -18 level, extends L NP reach by x2) • Timescale − Assume 2y from End-Mu2e to Start-Mu2e-II − (3+1)y of data taking at full intensity − Could occur on 2030 timescale 17 July 2018 Mu2e-II Expression of Interest / Fermilab PAC 2
Ou Our goal We want Mu2e-II to be a serious part of the next P5 discussion. For that to occur we need to address the following: − Is there interest in the community? − Is the science compelling? − Is the experimental concept sound? − Is the scope understood? − Is the remaining R&D specified? In the remainder of this talk I’ll address each of these issues. 17 July 2018 Mu2e-II Expression of Interest / Fermilab PAC 3
Co Community y Interest 17 July 2018 Mu2e-II Expression of Interest / Fermilab PAC 4
Ex Expression of Interest – Mu Mu2e-II II • Submitted to PAC 09 February 2018 • arXiv:1802.02599, Fermilab-FN-1052 • 130 Signatories, 36 Institutions, 6 Countries 17 July 2018 Mu2e-II Expression of Interest / Fermilab PAC 5
Sc Scienc nce Moti tivati tion 17 July 2018 Mu2e-II Expression of Interest / Fermilab PAC 6
Sc Science M Moti tivati tion • CLFV is a deep & unique probe of New Physics (NP) parameter space − Next generation experiments planned in Europe, Asia, and Americas − Probes complementary regions of NP space relative to rest of HEP program − Measured rates provide model discrimination arXiv:1709.00294v2[hep-ph] from L. Calibbi and G. Signorelli, Riv. Nuovo Cimento, 41 (2018) 71 17 July 2018 Mu2e-II Expression of Interest / Fermilab PAC 7
Sc Science M Moti tivati tion • Direct µ à e conversion is the “Golden Channel” of CLFV − Provides best sensitivity to CLFV − Probes broad array of NP models − Can provide unique information regarding underlying NP operators Winner! µ - N à e - N 17 July 2018 Mu2e-II Expression of Interest / Fermilab PAC 8
Sc Science M Moti tivati tion • Direct µ à e conversion is the “Golden Channel” of CLFV − Provides best sensitivity to CLFV Process Current Limit Next Generation exp t à µ h BR < 6.5 E-8 10 -9 - 10 -10 (Belle II, LHCb) t à µ g BR < 4.4 E-8 t à µµµ BR < 2.1 E-8 t à eee BR < 2.7 E-8 K L à e µ BR < 4.7 E-12 NA62 K + à p + e - µ + BR < 1.3 E-11 B 0 à e µ BR < 2.8 E-9 LHCb, Belle II B + à K + e µ BR < 9.1 E-8 10 -14 (MEG-II) µ + à e + g BR < 4.2 E-13 10 -15 ( µ 3e Phase-I) µ + à e + e + e - BR < 1.0 E-12 10 -17 (Mu2e, COMET Phase-II) µ - N à e - N R µ e < 7.0 E-13 (Current Limits taken from the PDG) 17 July 2018 Mu2e-II Expression of Interest / Fermilab PAC 9
Sc Science M Moti tivati tion • Direct µ à e conversion is the “Golden Channel” of CLFV − Provides best sensitivity to CLFV Process Current Limit Next Generation exp t à µ h BR < 6.5 E-8 10 -9 - 10 -10 (Belle II, LHCb) t à µ g BR < 4.4 E-8 t à µµµ BR < 2.1 E-8 t à eee BR < 2.7 E-8 K L à e µ BR < 4.7 E-12 NA62 K + à p + e - µ + BR < 1.3 E-11 B 0 à e µ BR < 2.8 E-9 LHCb, Belle II B + à K + e µ BR < 9.1 E-8 10 -14 (MEG-II) µ + à e + g BR < 4.2 E-13 10 -15 ( µ 3e Phase-I) µ + à e + e + e - BR < 1.0 E-12 10 -17 (Mu2e, COMET Phase-II) µ - N à e - N R µ e < 7.0 E-13 (Current Limits taken from the PDG) 17 July 2018 Mu2e-II Expression of Interest / Fermilab PAC 10
Sc Science M Moti tivati tion • Direct µ à e conversion is the “Golden Channel” of CLFV − Mu2e-II would provide the best sensitivity to CLFV in foreseeable future Process Current Limit Next Generation exp t à µ h BR < 6.5 E-8 10 -9 - 10 -10 (Belle II, LHCb) t à µ g BR < 4.4 E-8 t à µµµ BR < 2.1 E-8 t à eee BR < 2.7 E-8 K L à e µ BR < 4.7 E-12 NA62 K + à p + e - µ + BR < 1.3 E-11 B 0 à e µ BR < 2.8 E-9 LHCb, Belle II B + à K + e µ BR < 9.1 E-8 10 -14 (MEG-II) µ + à e + g BR < 4.2 E-13 10 -15 ( µ 3e Phase-I) µ + à e + e + e - BR < 1.0 E-12 10 -18 Mu2e-II 10 -17 (Mu2e, COMET Phase-II) µ - N à e - N R µ e < 7.0 E-13 (Current Limits taken from the PDG) 17 July 2018 Mu2e-II Expression of Interest / Fermilab PAC 11
Sc Science M Moti tivati tion • Direct µ à e conversion is the “Golden Channel” of CLFV − Sensitive to broad array of New Physics models Loops Supersymmetry Heavy Neutrinos Extended higgs models Contact Terms Compositeness Leptoquarks New Heavy Bosons / Anomalous Couplings 17 July 2018 Mu2e-II Expression of Interest / Fermilab PAC 12
Sc Science M Moti tivati tion V. Cirigliano et al., phys. Rev. D80 013002 (2009) aluminum titanium gold lead • Direct µ à e conversion is the “Golden 4 Channel” of CLFV V 2 − Once an observation is made, can R µ e (Z) / R µ e (Al) 3 change stopping target to probe underlying NP operator 2 V 1 S V 1 D V 2 1 D S y = nuclear scalar form factor, r n = nuclear neutron density 0 20 40 60 80 Z of stopping target 17 July 2018 Mu2e-II Expression of Interest / Fermilab PAC 13
Sc Science M Moti tivati tion SUSY Seesaw Mirror Leptons L. Calibbi, G. Signorelli Riv. Nuov. Cim 41 (2018) 71. P.Q. Hung, et al arXiv:1701.01761[hep-ph] Composite Higgs C. Hagedorn, M Serone JHEP 10 (2011) 83. Z Prime A. Falkowski, M. Nardeccia, R. Ziegler, JHEP 11 (2015) 173. LeptoQuarks A. Crivellin, et al., PRD 97 (2018) 015019. • Mu2e-II will have discovery sensitivity in broad array of New Physics models 17 July 2018 Mu2e-II Expression of Interest / Fermilab PAC 14
Mu Mu2e-II II Motiv ivatio ion Does Mu2e observe a signal? No Yes Celebrate discovery of CLFV! Celebrate successful Mu2e! Change target to study Increase rates, reduce bckgnds underlying New Physics to reach R µ e ~ 10 -18 Upgrade proton source & Upgrade proton source & detector to achieve precision detector to improve sensitivity • At conclusion of Mu2e there’s a strong motivation to upgrade proton source and detector to further pursue New Physics – Mu2e-II 17 July 2018 Mu2e-II Expression of Interest / Fermilab PAC 15
Exp Experimental Co Concept 17 July 2018 Mu2e-II Expression of Interest / Fermilab PAC 16
Fe Feasibility of Mu2e-II II Experim rimental l Concept • Mu2e-II Experimental concept is straightforward extension of Mu2e • White Paper arXiv:1307.1168 arXiv:1307.1168[hep-ex] − Associated workshops (April-2013, July-2013) − Follow-up workshops (July-2015, March-2016, June-2017) • Used Mu2e simulation & reconstruction framework to estimate backgrounds at Mu2e-II rates − Includes all sources of background: from, µ , p , beam e, & cosmic ray 17 July 2018 Mu2e-II Expression of Interest / Fermilab PAC 17
Fe Feasibility of Mu2e-II II Ex Experimental Co Concept Mu2e-II studies utilized full sophistication of Mu2e simulations and reconstruction software. Stopping Target Straw Tracker Crystal Calorimeter • A signal electron, together with all the other “stuff” occurring simultaneously (e.g. beam backgrounds, products from muon nuclear capture, DIOs), integrated over 500-1695 ns window − On average Mu2e (Mu2e-II) ~2500 (7500) hits in tracker during this time period • Capture products : 50% | Beam flash : 40% | other muon stops : 9% | DIO : 1% • On average a signal track leaves ~45 hits in tracker April 2018 D. Glenzinski | Fermilab 18
Feasibility of Mu2e-II Fe II Experim rimental l Concept 0.16 POT pulse - arrival/decay time ( 3M ) π × 0.14 arbitrary units - arrival time ( 1600 ) µ × - Al : decay/capture time ( 1600 ) 0.12 µ × - Ti : µ decay/capture time ( × 1600 ) 0.1 - Au : µ decay/capture time ( × 1600 ) Normalized per muon stop 0.08 Al 0.06 Ti 0.04 Delayed Live Window 0.02 0 0 200 400 600 800 1000 1200 1400 1600 1800 K. Knoepfel, et al ., arXiv:1307:1168 (2013). Time (ns) A. Czarnecki, X. Garcia I Tormo, & W.J. Marciano, PRD 84 (2011) 013006. • Aluminum & Titanium stopping targets investigated − Accounted for differences in density, decay fraction, end-point energy, DIO spectrum • Total background can be kept ~1 event − Discovery sensitivity continues to scale linearly with single-event-sensitivity 17 July 2018 Mu2e-II Expression of Interest / Fermilab PAC 19
Up Upgrade Scop ope an and R Req equired ed R& R&D Proton Beam 17 July 2018 Mu2e-II Expression of Interest / Fermilab PAC 20
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