non-standard neutrino interaction search with icecube …...1.0 0.5 0.0 0.5 1.0 p nsi p si | | e...
TRANSCRIPT
Non-standard neutrino interaction search with IceCube DeepCoreElisa Lohfink and Thomas Ehrhardt for the IceCube Collaboration
Institut fur Physik, Universitat Mainz
Non-standard neutrino interactions (NSI)
I NC scattering on first-generation charged fermions relevant forneutrino propagation (coherent forward scattering)
I NSI emerge from wide variety of neutrino mass models
I described by effective 4-fermion Lagrangian:
L NCNSI =−2
√2GF ∑
f =e,u,d
[ναγ
µLνβ
][f γµ
(εfLαβ
L+ εfRαβ
R)f]
NSI imprint on oscillation probabilities
I Hamiltonian for propagation in Earth matter:
Hν(Eν,x) =1
2Eν
Udiag(
0,∆m221,∆m2
31
)U†︸ ︷︷ ︸+Ve(x)
diag (1,0,0)︸ ︷︷ ︸+
ε⊕ee− ε⊕µµ ε⊕eµ ε⊕eτ
ε⊕∗eµ 0 ε⊕µτ
ε⊕∗eτ ε⊕∗µτ ε⊕ττ− ε⊕µµ
︸ ︷︷ ︸
cos
ϑ =
-1
cos
ϑ = -0.84
cos
ϑ =
-0.
98 coreinner
atmo
sphe
re
crust
mantle
upgoingdowngoing
outer core
1 5 10 50 100 500E (GeV)
1.00
0.75
0.50
0.25
0.00
cos
1.0
0.5
0.0
0.5
1.0
PNSI
PSI
e = 0.14| |
I atmospheric neutrinos atbaselines between 20 km andEarth diameter encounterdifferent matter density profiles
I difference in νµ survivalprobabilities for flavor-changingNSI ε⊕eµ of given strength
IceCube and DeepCore
I 1 km3 Cherenkov detector atGeographic South Pole
I 5160 optical modules equipped withdownward-looking PMTs in 1.5 km–2.5 km deepglacial ice, distributed across 86 vertical strings
I DeepCore sub-array with low energy threshold(∼ 5GeV)
I νµ, νµ CC identification capabilities(track-like events)
New results for 3 years of data
I one-by-one NSI constraints obtained for:· flavor violation: ε⊕αβ
=∣∣∣ε⊕
αβ
∣∣∣e iδαβ (α 6= β )· flavor non-universality: ε⊕ee(ττ)− ε⊕µµ (∈ R)
ε⊕ee−ε⊕µµ
ε⊕ττ− ε⊕µµ
−100
−10−1
−10−2
0
10−2
10−1
100
90%
allo
wed
regi
on
SI/universal NSI
IceCube preliminary
ε⊕eµ ε⊕eτ ε⊕µτ
−10−1−10−2
010−210−1
SI
δeµ δeτ δµτ0◦
90◦180◦270◦360◦
δαβ = 0◦, 180◦
Super-K 2011 (2d)
MINOS 2013IC 2017 (public)
global 2018 (w/ correl.)
IC DC 2018
IC DC 2020 (public)
IC DC 2020
I + 3D matter potential fit: strength & flavor structure· overall strength: ε⊕ ∈ [−1.2,−0.3]∪ [0.2,1.4]· rotation angles: ϕ12 ∈ [−9◦,8◦], ϕ13 ∈ [−14◦,9◦]
New high-statistics sample: 8 years of data
Enhanced event statistics in relevant regions of energy and zenith
I energy range extended up to 300 GeV, increasing sensitivity toflavor-violating NSI couplings (and control over systematics)
I binned χ2 fit in energy, event type (track-like/cascade-like) andcos(zenith) with nuisance parameters s
χ2mod =
bins
∑i
(µdatai −µMC
i
)2
µMCi + (σMC
i )2+
Nprior
∑j
(sj− scentralj )2
σ 2sj
8-year discovery potential and sensitivity
How well can SI be excluded at a given NSI truth hypothesis?
I discovery potential for eachfitted NSI parameter
I ε⊕eµ and ε⊕µτ: 3σ discoverypotential for 8y sample within 3ysample’s observed 90% exclusionlimit
0.000 0.007 0.014 0.020| |
0°
80°
160°
240°
320° IceCube preliminary
3 , 8y discoverypotential3y 90% observed
0
10
20
30
40
50
60
2 mod
0.000 0.035 0.071 0.106| e |
0°
80°
160°
240°
320°
e
IceCube preliminary
3 , 8y discoverypotential3y 90% observed
0
5
10
15
20
25
30
2 mod
4 2 0 2ee
0
4
8
12
16
2 mod
IceCube preliminary
8y discoverypotential3y observed
0.050 0.025 0.000 0.025 0.0500
4
8
12
16
2 mod
IceCube preliminary
8y discoverypotential3y observed
8y sensitivity: MC-based NSI exclusion power in absence of NSI
I assume complexparameters
I expect strongestmodel-independentbounds on flavor-violation and non-universality NSI strengthsfor Earth matter so far
IceCube preliminary
References[1] P. S. Bhupal Dev et al., SciPost Phys. Proc. 2, 001 (2019), [2] M. G. Aartsen et al. (IceCube
Collaboration), JINST 12 (03), P03012, [3] G. Mitsuka et al. (Super-Kamiokande Collaboration), Phys.
Rev. D 84, 113008 (2011), [4] P. Adamson et al. (MINOS Collaboration), Phys. Rev. D 88, 072011 (2013),
[5] J. Salvado et al., J. High Energy Phys. 2017 (1), 141, [6] I. Esteban et al., J. High Energy Phys. 2018
(8), 180, [7] M. G. Aartsen et al. (IceCube Collaboration), Phys. Rev. D 97, 072009 (2018), [8] S. V.
Demidov, J. High Energy Phys. 2020 (3), 105
background image credit: Bill Spindler (www.southpolestation.com)
[email protected], [email protected]
vacuum SI
NSI
ε⊕αβ≈ εeV
αβ+ 3(
εuVαβ
+ εdVαβ
)(vector couplings)
see poster ofE. Bourbeau
}90% CL
here: flavor violation
constrained to real
plane
to be published soon
see posters of K.Leonard, T. Stuttard