Progress in Neutrino-Nuclear Scattering much ado about ν-A things

28 Pages·2016·1.86 MB·English

Progress in Neutrino-Nuclear Scattering!
much ado about ν-A things
Image from recent
workshop on neutrino
scattering (NuInt2014)
Kendall Mahn!
Michigan State University
Outline
Talks in this session:
Theoretical status Results from MINERvA
Results from MicroBooNE
Future experiments
What is neutrino scattering?!
Why is neutrino nuclear (ν-A) scattering important to oscillation expt’s?!
What is the current state of knowledge about ν-A?
2
Processes in Neutrino Scattering!
merely players
Energy transfer!
figure from Ref 1
• Charged Current Quasi Elastic (CCQE) and multinucleon processes (2p2h)
Observable
2p2h
CCQE
µ(cid:1)" ν µ(cid:1)"
ν
neutrino (anti) µ"
µ" "
"
W"
W"
• muon or electron (+)
N,"N" N’,N’"
N" N’"
• proton (neutron)
3
Processes in Neutrino Scattering!
merely players
Energy transfer!
figure from Ref 1
Production of pions, CC1π+/0/- and NC1π+/0/-
•
CCπ" CCπ"
" µ(cid:1)" " µ(cid:1)"
ν
ν
µ"
" µ"
" "
"
π+"
resonant coherent
W" W"
π"
A" A"
N"
Δ"
N’"
4
Neutrino Sources and Nuclear Effects!

)
.
b 0.8
r
T2K off-axis flux
a [Ref 2]
(
0.7

T2K on-axis flux
x
u
l MiniBooNE flux
0.6
f

µ NOνA near detector flux
ν
0.5
MINERνA flux
0.4
DUNE ~1-10 GeV
0.3
0.2
0.1
0.0
0 1 2 3 4 5 6
E (GeV)
ν
Neutrinos probe the V-A nature of the weak interaction
•
But, neutrino decay-in-flight beams are not mono-energetic
•
Spread of beam is larger than nuclear effects
•
5
Nuclear Effects Example!

Multiple processes contribute to each observable topology
•
CCQE-like observable topology: muon, proton, no pions
•
Includes true CCQE, 2p2h, CC1π (pion absorbed in nucleus)
•
"
CCπ
2p2h
CCQE
µ(cid:1)" µ(cid:1)" ν " µ(cid:1)"
ν
ν
µ"
µ"
µ" " "
" "
W" W"
W"
N,"N" N’,N’" π"
N" N’"
N"
Δ"
N’"
6
Why is ν-A important for oscillation expts?!
Oscillation depends on energy
•
Estimate from hadronic and/or leptonic information
•
2
2 2
m m m + 2m E
� �n µ
p n µ
QE E = E + E
E = � �
⌫ µ hadronic
�
2(m E + p cos � )
�n µ µ µ
�
X
s
t CCQE
Nuclear effects bias i
•
n
[Ref 3]
U ×
Nieves multinucleon ( 5)

true and estimated y
r ∆ ×
pionless -decay ( 5)
a
r
neutrino energy
t
i
b
r
A
muon
Neutrino
-1 -0.5 0 0.5
QE
E - E (GeV)

hadronic reco true
Why is ν-A important for oscillation expts?!
Multinucleon Feed-down, ND280 Flux Multinucleon Feed-down on Oscillated Flux
×109 ×103
140
ν ν
E 1000 E
Near detector ! Far detector!
* *
x x
120
u u
l E - E QE l E - E QE
F 800 F
ν ν ν ν
100
smearing for smearing for
600
80
E =0.8 GeV E =0.8 GeV
ν ν
400 60
40
200
20
0
0 0.5 1 1.5 2
0
0 0.5 1 1.5 2
E (GeV)
ν
E (GeV)
ν
N D(⌫ ) =�( E ) �(E , A) ✏
µ ⌫ ⌫ ND
⇥ ⇥
F D(⌫ ) =�( E ) �(E , A) ✏ P (⌫ ⌫ )
µ ⌫ ⌫ F D µ e
⇥ ⇥ ⇥ !
Even with a near detector, critical reliance on model !
•
2p2h feed-down to oscillation peak from [Ref 4]
•
8
Summary of ν-A issues!
there is nothing either good or bad, but
thinking makes it so
• Current and future long and short baseline oscillation rely on
modeling of neutrino interaction physics even with near
detectors. Need:
• Predicted signal, background efficiency, energy estimate for
• Muon and electron neutrinos, and antineutrinos
• But, outstanding QE, 1π puzzles indicate our understanding is
incomplete
Path forward: test modern models for processes of interest
with a variety of experimental probes
9
Recent Progress, Effort in ν-A !
The undiscovered country
Unprecedented experimental information! ArgoNEUT, MicroBooNE,
•
MINERvA, NOvA, T2K
Range of beam energies, target materials, with neutrinos and
•
antineutrino sources
Coming soon: new information from neutrons (ANNIE, CAPTAIN)
•
Impressive model development in neutrino interaction software
•
programs (GENIE [Ref 5], GiBUU, NEUT, NuWro)
New alliance between theorists and experimentalists (NuSTEC)
•
Next School will be in October 2017
•
See
posters on
Subscribe [email protected] (see backup)
•
interaction
models
10