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Doubly-charged scalars at high-energy and high-precision experiments - - PowerPoint PPT Presentation
Doubly-charged scalars at high-energy and high-precision experiments - - PowerPoint PPT Presentation
Doubly-charged scalars at high-energy and high-precision experiments B HUPAL D EV Washington University in St. Louis with M. J. Ramsey-Musolf (UMass) and Y. Zhang (WashU), arXiv:1805.0xxxx PHENO 2018 University of Pittsburgh May 8, 2018
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Two Frontiers: Energy versus Precision
[Le Dall, Pospelov, Ritz (PRD ’15)]
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Two Frontiers: Energy versus Precision
Complementary and intertwined. Need input from both to probe new physics.
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Two Frontiers: Energy versus Precision
28 m
liquid hydrogen target upstream toroid hybrid toroid detector systems electron beam
Example: LHC versus MOLLER
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MOLLER Experiment
Measurement Of a Lepton Lepton Electroweak Reaction
2 8 m
liquid hydrogen target upstream toroid hybrid toroid detector systems electron beam
Scattering of longitudinally polarized electrons off unpolarized electrons. Upgraded 11 GeV electron beam in Hall A at JLab.
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Parity-Violating Asymmetry
APV = σR − σL σR + σL
e- e- p1 p2 p1
- p2
- e-
e-
- p1
p2 e- e- p1
- p2
- Z
e- e- e- e- Z e- e- e- e-
- ASM
PV = mE
GF √ 2πα 2y(1 − y) 1 + y4 + (1 − y)4 Qe
W
For the MOLLER design, ASM
PV ≈ 33 ppb (including 1-loop effect).
Goal: δAPV = 0.7 ppb. [J. Benesch et al. [MOLLER Collaboration], arXiv:1411.4088 [nucl-ex]] Achieve a 2.4% precision in the measurement of Qe
W.
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Sensitive to New Physics
e− e− e− e−
Λ
- |g2
RR − g2 LL|
= 1 √ 2GF|∆Qe
W|
≃ 7.5 TeV
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Case Study: Doubly Charged Scalar
e− e− fee fee H−− e− e−
MPV ∼ |(fL)ee|2 2(M±±
L
)2 (¯ eLγµeL)(¯ eLγµeL) + (L ↔ R) . MOLLER Sensitivity : MH±±
L,R
|(fL,R)ee| 5.3 TeV .
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Case Study: Doubly Charged Scalar
100 1000 104 10-3 10-2 0.1 1 10
MHL
±± [GeV]
δAPV [ppb]
MOLLER prospect | ( f
L
)
ee
| = 1 | ( f
L
)
ee
| = . 1 | ( f
L
)
ee
| = . 1
[BD, Ramsey-Musolf, Zhang ’18]
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Why Doubly Charged Scalar?
Neutrino Mass via Type-II Seesaw LY = − (fL)ij ψT
L, iCiσ2∆LψL, j + H.c.
mν = √ 2 fLv∆ = U mνUT .
[Schechter, Valle (PRD ’80); Mohapatra, Senjanovi´ c (PRD ’81); Lazarides, Shafi, Wetterich (NPB ’81)]
Fixes the elements of fL (up to an overall scale)
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LFV Constraints
Process Experimental limit
- n BR
Constraint on Bound ×
- MHL
100 GeV 2 µ → eγ < 4.2 × 10−13 |(f †
L fL)eµ|
< 2.4 × 10−6 µ → 3e < 1.0 × 10−12 |(fL)µe||(fL)ee| < 2.3 × 10−7 τ → eγ < 3.3 × 10−8 |(f †
L fL)eτ|
< 1.6 × 10−3 τ → µγ < 4.4 × 10−8 |(f †
L fL)µτ|
< 1.9 × 10−3 τ → e+e−e− < 2.7 × 10−8 |(fL)τe||(fL)ee| < 9.2 × 10−5 τ → µ+µ−e− < 2.7 × 10−8 |(fL)τµ||(fL)µe| < 6.5 × 10−5 τ → e+µ−µ− < 1.7 × 10−8 |(fL)τe||(fL)µµ| < 7.3 × 10−5 τ → e+e−µ− < 1.8 × 10−8 |(fL)τe||(fL)µe| < 5.3 × 10−5 τ → µ+e−e− < 1.5 × 10−8 |(fL)τµ||(fL)ee| < 6.9 × 10−5 τ → µ+µ−µ− < 2.1 × 10−8 |(fL)τµ||(fL)µµ| < 8.1 × 10−5
[BD, Rodejohann, Vila (NPB ’17)]
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MOLLER versus LFV
10-2 0.1 1 10 10-3 10-2 0.1 1 10
vΔ [eV] |(fL)ee|
NH, MHL
±± = 1 TeV
excluded by μ → eee excluded by μ → eγ M O L L E R p r
- s
p e c t
[BD, Ramsey-Musolf, Zhang ’18]
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MOLLER versus LFV
10-2 0.1 1 10 10-2 0.1 1 10
vΔ [eV] |(fL)ee|
IH, MHL
±± = 1 TeV
e x c l u d e d b y μ → e e e e x c l u d e d b y μ → e γ M O L L E R p r
- s
p e c t
[BD, Ramsey-Musolf, Zhang ’18]
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Parity-Violating Left-Right Model
LY ⊃ − (fR)ij ψT
R, iCiσ2∆RψR, j + H.c..
Could have fR = fL at low scale. [Chang, Mohapatra, Parida (PRL ’84)] fR is not related to the neutrino oscillation data. LFV constraints do not restrict (fR)ee anymore. Other relevant constraints:
Neutrinoless double beta decay Bhabha scattering at LEP: e+e− → e+e−. Drell-Yan process at LHC: pp → γ∗/Z∗ → H++H−−.
Future prospects at ILC/CLIC: e+e− → e±e±H∓∓
R
and e±γ → e∓H±±
R
.
[BD, Mohapatra, Zhang ’18]
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Parity-Violating Left-Right Model
0.5 1 5 10 10-3 10-2 0.1 1 10
MHR
±± [TeV]
|(fR)ee|
parity-violating case
ee → ee
MOLLER
dilepton limits
0νββ [NH] [IH]
ILC CLIC perturbative limit
[BD, Ramsey-Musolf, Zhang ’18]
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