Post on 26-Apr-2022
物理学院SCHOOL OF PHYSICS
Precision measurement and new physics searches by neutrino oscillation experiments
Jian Tang
tangjian5@mail.sysu.edu.cn
Seminar @ SJTU & TDLi Institute, Sept. 30
Collaborators:
Yong Du, Hao-Lin Li, Jiang-Hao Yu (CAS-ITP)
Zhuo-Jun Hu, Jia-Jie Ling,
Sampsa Vihonen, Tse-Chun Wang, Yi-Bing Zhang
Ref: JHEP01(2021)124, JHEP03(2021)019, arXiv: 2106.15800
2021/09/30 Jian Tang
Table of contents
• Motivations
• Non-unitarity(NU) v.s non-standard interactions(NSIs)
• Global fits of mixing parameters without unitarity
• Constraints of NSIs based on SMEFT
• Summary
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Three-generation neutrino oscillations
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• For 3 ν framework , we have 6+1 free parameters in neutrino oscillations:
P (θ12, θ13, θ23, δ, Δm212, Δm31
2) + ρ (in matter)√ √ √ √? √?
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Where are neutrinos from?
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Natural source
Artificial source
10-4 10-3 104103 105 106 107 1010109 1011108 1012
keV MeV GeV TeV
E [eV]
~Electron mass ~Proton mass ~LHC
???
???
??
??
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Working principles of neutrino oscillation experiments
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• Get the neutrino source as clean as possible. Muon decay v.s pion decay beams.
• Deploy the best detector to reconstruct the oscillated neutrino spectra: Gd-WC, LAr
TPC, scintillator detector with flavour&charge identifications…
• Data mining: precision measurement & discovery of new physics…
Neutrino source
Near detector(cancellation of
systematics in flux&X-section...)
Far detector
Baseline
L ~ E/m2
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An example: T2K
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K. McFarland, Neutrino InteractionUncertainties @ NNN2018
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Simulations of neutrino oscillations w/o new physics
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By GLoBES
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Lots of neutrino experiments to get a new horizon
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More are coming…
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WC detectors: KamiokandeSKHyperK
• Bigger than bigger! PMT technology revolutionized!
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3 kton WC 20% coverage
with 20’’ PMT
50 kton WC 40% coverage
with 20’’ PMT
260 kton WC 40% coverage
with 20’’+HQE PMT
• Construction started in 2020.
• Data taking from 2027.
• J-PARC neutrino beam will be upgraded from 0.7 to 1.3 MW
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LAr TPC: DUNE
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Courtesy: Guang Yang@NuFact2021
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LSc: DYB (20 t*8) JUNO (20 kt)
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• Daya Bay neutrino experiment: mission completed!
Credit: Miao He
Dec. 12, 2020
MCP-PMT
20’’+HQE
MH sensitivity:
∆χ2= 15.07
By GLoBES
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NuFACT2021: WG1 proposed questions
• What is the neutrino mass ordering?
• Are there CP violations in the lepton sector?
• How much precision shall we reach to tell new physics?
• What are the current and future systematic limitations on precision measurement and how to address them?
• Is the neutrino mixing matrix unitary?
• Are there non-standard neutrino interactions?
• Are there more than three-flavor neutrinos?
• How to deal with the reactor flux deficit?
• How consistent are results from NOvA and T2K?
• How to examine neutrino mass models based on flavor symmetries (A4, S4, Modular…)?
• What’s next even after neutrino mass ordering and Dirac CP phase?
• …
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Table of contents
• Motivations
• Non-unitarity(NU) v.s non-standard interactions(NSIs)
• Global fits of mixing parameters without unitarity
• Constraints of NSIs based on SMEFT
• Future prospects
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Non-unitary neutrino mixings (NU)
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Non-Standard Interactions (NSIs)
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NSI happens to neutrino propagation in matter NSI at neutrino productions
• New physics beyond SM: new particles, new couplings,
new phenomenon...
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Discovery of CPV affected by NU/NSIs
16Phys.Rev.D 95 (2017) 3, 033005JHEP 10 (2016) 138 by Dr. Shao-Feng Ge
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Table of contents
• Motivations
• Non-unitarity(NU) v.s non-standard interactions(NSIs)
• Global fits of mixing parameters without unitarity
• Constraints of NSIs based on SMEFT
• Future prospects
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• Reduced constraints without the unitary assumption in the quark mixing.
• Let’s keep the democratic way in quark and lepton mixing?18
What if there is non-unitary mixing?
?
Lepton mixing
www.nu-fit.org
No unitarity assumption here!
Quark mixing
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Simple mathematics w/o unitarity assumption
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Unitarity
Non-unitarity(NU)
• Only 4 real parameters with unitarity.
• Now we have 13 real parameters after rephrasing fields for NU!
18 real parameters in linear algebra
-5 by rephrasing fields in physics
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What if there is non-unitary mixing?
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• Correlations between 3nu mixing matrix
elements without unitarity assumption.
• Octant degeneracies get worse for NU.
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What if there is non-unitary mixing?
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• Nice precision in the first and second row/column.
• Tau neutrino physics are to be improved for better constraints on 3rd row/column!
ClosureNormalizations
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Table of contents
• Motivations
• Non-unitarity(NU) v.s non-standard interactions(NSIs)
• Global fits of mixing parameters without unitarity
• Constraints of NSIs based on SMEFT
• Future prospects
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Working principle of effective field theory (EFT)
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EFT: connecting low-energy phenomenon to high-energy scale
Credit: Adam Falkowski
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• Start from a UV theory
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• Matching by covariant derivative expansion, EoM
• Solve for classical solution
An example for demonstration
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An example for demonstration
• Put the classical solution back to Lagrangian density
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• Fierz transformation to Warsaw basis
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An example for demonstration
• Run down from scale M to electroweak scale v
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• Probably generate non-zero Wilson coefficients other than Cle
• Matching at electroweak scale to LEFT
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Matching between QM and QFT NSIs
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• QM NSIs are fully independent without much info
about the underlying theory.
• QFT NSIs allow their correlations.
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EFT: connecting low-energy phenomenon to high-energy scale
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• Dimension-6 operators only
• Neutrino masses are generated by
dimension-5 Weinberg operators
Effective operators
Cut-off scale
Wilson coefficient
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SMEFT-NSIs by T2K and NOvA
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• T2K and NOvA are already sensitive to new physics around 20 TeV.
• Correlations among different dimension-6 operators play important roles.
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SMEFT-NSIs by reactor neutrino experiments
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• Reactor neutrino experiments are sensitive to new physics around 5 TeV.
• Complementarity between LBL and reactor expts due to different sets of operators
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Table of contents
• Motivations
• Non-unitarity(NU) v.s non-standard interactions(NSIs)
• Global fits of mixing parameters without unitarity
• Constraints of NSIs based on SMEFT
• Future prospects on SMEFT-NSIs
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Democratic treatment of CKM and PMNS mixing
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Smelli
Quark mixing v.s neutrino mixing/scattering
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SMEFT-NSIs by T2HK and DUNE
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NC-NSIs
CC-NSIs
• Cover 1635 SMEFT operators in dimention-6. ND is important to constraint SMEFT-NSIs.
• DUNE has better sensitivity than T2HK due to the longer baseline.
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SMEFT-NSIs by JUNO w/o TAO and COHERENT
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CC-NSIs
NC-NSIs
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Summary
• Neutrino oscillation is the first direct evidence BSM.
• Discovery of CPV & determination of MH is around the corner. Neutrino will be used for new physics searches.
• New physics might be hidden in the uncertainties.
• Unitary mixing should not be taken by default, as tau neutrino-related part is yet to be improved.
• We can have better knowledge of underlying theory by RGE running and matching in different scales to connect the low-energy neutrino oscillation experiments and the UV completion model in SMEFT.
• Let’s work together to discover new physics with neutrinos…
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Precision measurement and tau-neutrino physics?
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• Pushing precision to sub-percent level and probe new physics
arXiv:2108.11107
THANK YOU
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