neutrino shadow play - indico.ihep.ac.cnindico.ihep.ac.cn/event/7239/material/slides/0.pdf · 2...

Neutrino Shadow Play

Xianguo LU/ 卢显国 University of OxfordHEP Seminar, UCAS

Beijing, 7 September 2017

皮影 Shadow playSource: http://www.cnhubei.com/ztmjys-pyts

http://www.cnhubei.com/ztmjys-pyts

2

Outline

1. Understanding matter-antimatter asymmetry with neutrinos

2. Nuclear effects in neutrino-nucleus interactions

3. Measuring neutrino interactions

4. A neutrino shadow play

Act One: Neutrino energy independent measurement of nuclear effects

Act Two: Nuclear effect independent measurement of neutrino energy spectra

5. Summary

3

planetxnews.com

NASA /WMAP

Matter-antimatter symmetric

Cosmic Microwave

Early Universe

“Present”Time

4

Matter-antimatter asymmetric

Cosmic Microwave Background

Early Universe

“Present”Time

NASA /WMAP

planetxnews.com

5NASA-HQ-GRIN NGC 4414

Material World Antimaterial World

Matter-antimatter asymmetric

Early Universe

“Present”Time

planetxnews.com

6

Matter-antimatter asymmetricSakharov Conditions:Sakharov Conditions:Baryon number violationC- and CP-symmetry Violation (CPV)Interactions out of thermal equilibrium

Early Universe

Material World Antimaterial World“Present”

Time

NASA-HQ-GRIN NGC 4414

planetxnews.com

7

Matter-antimatter asymmetricSakharov Conditions:Baryon number violationC- and CP-symmetry Violation (CPV)Interactions out of thermal equilibrium

Early Universe

Material World

p

n

“Present”Time

NASA-HQ-GRIN NGC 4414

By Rainer Klute/Arpad Horvath/MissMJ FNAL

planetxnews.com

8

n

p


9

n

p

Quarkonic CPV insufficient

Leptonic CPV (LCPV) unknown


10

νµ ν

µ

νµ ν

µ

νµ ν

µ

νµ ν

e

νµ ν

e

νµ ν

µ

νµ ν

µ

νµ ν

µ

νµ ν

e

νµ ν

e

Leptonic CP Symmetry

νµ ν

µ

νµ ν

µ

νµ ν

µ

νµ ν

µ

νµ ν

e

νµ ν

µ

νµ ν

µ

νµ ν

e

νµ ν

e

νµ ν

e

LCPV


*no matter effect

11


Accelerator

Detector

Rev.Mod.Phys. 84 (2012) 1307

νµ ν

eν

µ ν

e

12

Neutrino Oscillations

PMNS matrixPontecorvo–Maki–Nakagawa–Sakata

13


PMNS matrix

θij ≠ 0, δ

CP-phase irreducible → leptonic CP violation

14


PMNS matrix

θij ≠ 0, δ


With a νµ beam

“CP-odd term” in appearance channels allow extraction of δCP

using

neutrino and anti-neutrino beams, up to ±30% effect at T2K – unique opportunities with accelerator neutrinos

Neutrino (flavor) oscillations depend on mixing angles, δCP

-phase and mass differences.

PMNS matrix

* neglecting matter effects

15


PMNS matrix

θij ≠ 0, δ


With a νµ beam



PMNS matrix

CP-odd term in appearance channels allow extraction of δCP

using neutrino

and anti-neutrino beams, up to ±30% effect at T2K – unique opportunities with accelerator neutrinos

by CPT symmetry

flip sign


16


PMNS matrix

θij ≠ 0, δ


With a νµ beam



PMNS matrix

flip sign

by CPT symmetry

CP-odd term in appearance channels allow extraction of δCP

using neutrino

and anti-neutrino beams, up to ±30% effect at T2K – unique opportunities for experiments with accelerator neutrinos

solar + KamLAND et al.


17

The T2K Experiment

Diagram by Kirsty Duffy

Japan Proton Accelerator Research

Complex (J-PARC)

18

The T2K Experiment

Charge selection on neutrino parents → ν or ν mode

Phys.Rev.Lett. 116 (2016) no.18, 181801



Complex (J-PARC)

19

BEAM

Crossed arrays of 9-ton iron-scintillator detectors ➔ Monitor neutrino beam stability and beam spatial

profile➔ estimate beam flux uncertainty➔ stand-alone cross-section measurements

The T2K Experiment

BEAM



Complex (J-PARC)

20

The T2K Experiment



Complex (J-PARC)

Off-axis (OA) 2.5º

BEAMOff-axis neutrino beams:Reduce dependence on pion energy → narrow-band

Spectrum peak at maximum disappearance @SK

Phys.Rev. D87 (2013) no.1, 012001

21

Off-axisbeam

Dipole magnet (0.2T)

T2K off-axis near detector (ND280)

22

TPC

TPC

TPC

FGD1

FGD2

Tracker:● FGD: Fine-Grained Detector

1. plastic scintillator C8H

8

target 2. C

8H

8 + H

2O target

● Time Projection Chamber (TPC)

● constrain beam flux and cross

section for oscillation analysis● stand-alone neutrino

interaction measurements

T2K off-axis near detector (ND280)

23

Source: http://www-sk.icrr.u-tokyo.ac.jp/sk/detector/image-e.html

T2K far detector:Super-Kamiokande

● 50 kt water-Cherenkov● 11129 20-inch PMTs in inner

detector; 1885 8-inch PMTs in outer veto detector→ time and amplitude of Cherenkov light

µ, e identification→ detect propagated ν from J-PARC→ E

ν rec. from µ/e kinematics

http://www-sk.icrr.u-tokyo.ac.jp/sk/detector/image-e.html

24

Source: http://www.ps.uci.edu/~tomba/sk/tscan/th

e±µ±

● 50 kt water-Cherenkov● 11129 20-inch PMTs in inner

detector; 1885 8-inch PMTs in outer veto detector

T2K far detector:Super-Kamiokande

µ, e identification→ detect propagated ν from J-PARC via time and amplitude of Cher. light→ E

ν rec. from µ/e kinematics

N N'

µ-/µ+/e/e+νµ/ν

µ/ν

e/ν

e

W

Charged-Current Quasi-Elastic(CCQE)

http://www.ps.uci.edu/~tomba/sk/tscan/th

25

SK event reconstruction

NEW since 2016 summer:New reconstruction algorithm: fiTQun (likelihood-based)Re-optimizing fiducial volume: ~30% increase in effective statistics

26


Minimum distance to wall

Distance to wall alongparticle trajectory


27


Old FV

New FV

● Larger Towall = finer sampling of ring = better reconstruction● Optimize cuts accounting for statistical and systematic errors


28

Data collection history(Protons-On-Target)

29

Data collection history

start of ν-mode

(Protons-On-Target)

30


start of ν-mode

Published resultsPhys. Rev. Lett. 118 (2017) no.15, 151801POT: 7.5×1020 ν, 7.5×1020 ν

(Protons-On-Target)

31


start of ν-mode

Published resultsPhys. Rev. Lett. 118 (2017) no.15, 151801POT: 7.5×1020 ν, 7.5×1020 ν

Stable beam power at 470 kW, doubling ν POT in 1 year (NEW)This talk: 14.7×1020 ν, 7.6×1020 ν, totaling 29% of approved

(Protons-On-Target)

32

ν-mode FGD1 pµ

Near Detector Samples

µ− CC0π µ− CCNπµ− CC1π

µ+ 1-track

µ− 1-track µ− N-track

µ+ N-track

ν-mode FGD1 pµ

● Data➔ 6 ν-mode samples (FGD1,2)➔ 8 ν-mode samples (FGD1,2)

● Model➔ Flux prediction: beamline

MC tuned with ext. data (NA61) + beam monitor, INGRID

➔ Cross-section models tuned to ext. measurements.

33

ν-mode FGD1 pµ

Near Detector Fit – post-fitν-mode FGD1 pµ

● Data➔ 6 ν-mode samples (FGD1,2)➔ 8 ν-mode samples (FGD1,2)

● Simultaneous fit of pµ, θ

µ➔ Data well reproduced:

p-value 0.47➔ Fitted flux parameters near

nominal, most within 1σ prior uncertainty

➔ Nucleon correlations (NEW): 2p2h, RPA effects significantly adjusted

➔ flux × cross section at SK sys. error 13% → 3 %.

µ− CC0π µ− CCNπµ− CC1π

µ+ 1-track

µ− 1-track µ− N-track

µ+ N-track

34

240 νµ

74 νe

15 νe

68 νµ

7 νe

Event distributions and oscillation fit

CC1π+ sampleCCQE-like sample

● Reconstructed neutrino energy distributions at Super-Kamiokande➢ Dotted: data; histogram: oscillation fit results, p-value 0.42

N ∆

eνe

W

CC1π+ via ∆ production

(No CC1π– sample due to π– absorption)

35

240 νµ

74 νe

15 νe

68 νµ

7 νe



● νµ rate lower than fit, consistent with uncertainties.

N ∆

eνe

W



36

240 νµ

74 νe

15 νe

68 νµ

7 νe



● CC1π νe rate: 15 events observed vs. 6.92 maximum prediction

● P-value 0.12 for upward or downward fluctuation in at least 1 of 5 samples

N ∆

eνe

W



37

Atmospheric parameter constraints

● Fit normal and inverted hierarchies separately● Final systematics pending, possible additional contribution from interaction

models (no significant impact on δCP

)

Final systematics pendingT2K + reactor (PDG16)

38

T2K only T2K + reactor (PDG16)

scale

● Left: T2K best-fit result and confidence intervals compared to PDG 2016: consistent➢ ν data bring in δ

CP-sensitivity

● Right: T2K results with reactor constraint (PDG 2016), contour range much reduced.

Appearance parameter constraints

39

Measurement of δCP

CCQE-like νe and ν

e rate compared to δ

CP=0 predictions:

➢ Excess in neutrino (top)➢ Deficit in antineutrino (bottom)

74 νe

7 νe

40

Measurement of δCP

SK detector

SK FSI+SI+PN

ND280 constrained flux & xsec

σ(νe)/σ(ν

e) NC1γ NC

otherOscillationparameter variation

Total systematic

error

1.60 1.57 2.50 3.03 1.49 0.18 0.79 4.85

Percentage errors on predicted event rate ratio between νe and ν

e samples:

relevant for δCP

extraction

41

Measurement of δCP

SK detector

SK FSI+SI+PN


σ(νe)/σ(ν

e) NC1γ NC


Total systematic

error

1.60 1.57 2.50 3.03 1.49 0.18 0.79 4.85


e samples:

relevant for δCP

extraction

ND280 constraint on flux & cross section, reducing error from 13% to 3%.

42

Measurement of δCP

SK detector

SK FSI+SI+PN


σ(νe)/σ(ν

e) NC1γ NC


Total systematic

error

1.60 1.57 2.50 3.03 1.49 0.18 0.79 4.85


e samples:

relevant for δCP

extraction


Don’t precisely measure σ(νe) and σ(ν

e) in ND280. Apply a theoretically motivated

error based on Phys.Rev. D86 (2012) 053003.

43

Measurement of δCP

SK detector

SK FSI+SI+PN


σ(νe)/σ(ν

e) NC1γ NC


Total systematic

error

1.60 1.57 2.50 3.03 1.49 0.18 0.79 4.85


e samples:

relevant for δCP

extraction





Neutral current (NC) interactions not constrained by ND280. Theoretical models constrained by external measurements.

44

Measurement of δCP

SK detector

SK FSI+SI+PN


σ(νe)/σ(ν

e) NC1γ NC


Total systematic

error

1.60 1.57 2.50 3.03 1.49 0.18 0.79 4.85





Neutral current (NC) interactions not constrained by ND280. Theoretical models constrained by external measurements.

Total error 4.85% on event rate ratio νe / ν

e (10% by design).


e samples:

relevant for δCP

extraction

45

Measurement of δCP

T2K + reactor (PDG16)

2σ CLIntervals

Best fit point: -1.83 radians in Normal Hierarchy2σ CL interval:

Normal Hierarchy: [-2.98, -0.60] radiansInverted Hierarchy: [-1.54, -1.19] radians

CP conserving values 0, π both fall outside 2σ CL intervals

46

arXiv:1609.04111

sys. imprtNormal MH: unknown

δCP

= -π/2

arXiv:1609.04111

Normal MH: unknown

● Extension of T2K run to 20×1021 POT (~2026)● Currently approved for 7.8×1021 POT (~2021) ● Accelerator and beam-line upgrades to 1.3 MW

3-σ sensitivity for CP violation for favorable parameters, if✔ Full T2K-II exposure 20×1021 POT ✔ 50% improvement in effective statistics: horn

current, SK event reconstruction ✔ Systematic uncertainties down to 2/3 of current

size: ND upgrade

arXiv:1609.04111

T2K-II

47

Outline







5. Summary

48

static nucleon target

49

Quasi-elastic scattering (QE)

charged current (CC) ν → l'

quasi-elastic (QE) N → N'

static nucleon target

N N'

µ-/µ+/e/e+νµ/ν

µ/ν

e/ν

e

W

Charged-Current Quasi-Elastic(CCQE)

50

nuclear target(bound nucleon)

Fermi motion (FM) biases Eν reconstruction

51


Multinucleon correlations: cross section unknown, strong bias to all final-state kinematics

Science 320 (2008) 1476-1478

initial correlation large relative motion

52

Science 320 (2008) 1476-1478

initial correlation large relative motion

nuclear target(bound nucleons)


Multinucleon correlations: cross section unknown, strong bias to all final-state kinematics

● Impulse approximation: independent particles● In particle-hole excitation:

➔ RPA (random phase approximation): sum of 1p1h excitation (over all pairs) ~ ground state correlations (long range)

➔ npnh (n≥2): sub-leading terms in ph expansion ~ multinucleon correlations (short range)

53

Resonance production (RES)

nuclear target


QE-like N → N'including resonance production (RES) ∆ → N'π followed by π absorption


Multinucleon correlations: cross section unknown, strong bias to all final-state kinematicsQE-like: π absorbed in nucleus ← final-state interaction (FSI)

N ∆

eνe

W


54

nuclear emission

nuclear target



Multinucleon correlations: cross section unknown, strong bias to all final-state kinematicsQE-like: π absorbed in nucleus ← final-state interaction (FSI)FSI → energy-momentum transferred in nucleus, possible nuclear emission

QE-like N → N'including resonance production (RES) ∆ → N'π followed by π absorption

55nuclear effects

quasielastic– binding energy

– Fermi motion

– Final-state interactions

– multinucleon correlations

Neutrino energy

56

interaction dynamics

nuclear effects

– quasielastic

– resonant

– DIS– binding energy

– Fermi motion



Neutrino energy

57


nuclear effects

nuclear targets

– quasielastic

– resonant


– Fermi motion


– C

– O

– Fe

– Pb

– Ar


Neutrino energy

58


nuclear effects

nuclear targets

– quasielastic

– resonant


– Fermi motion


– C

– O

– Fe

– Pb

– Ar


Neutrino energy

T2K, arXiv:1701.00432

59


nuclear effects

nuclear targets

– quasielastic

– resonant


– Fermi motion


– C

– O

– Fe

– Pb

– Ar


Neutrino energy

T2K, arXiv:1701.00432

60


nuclear effects

nuclear targets

– quasielastic

– resonant


– Fermi motion


– C

– O

– Fe

– Pb

– Ar


Neutrino energy

T2K, arXiv:1701.00432

61

Outline







5. Summary

62Source: http://vmsstreamer1.fnal.gov/VMS_Site_03/VMSFlash/090924Minerva/index.htm

MINERvA

http://vmsstreamer1.fnal.gov/VMS_Site_03/VMSFlash/090924Minerva/index.htm

63

Nucl.Instrum.Meth. A743 (2014) 130-159

Scintillator trackerCharged lepton: seenProton: track

MINERvA

64

Nucl.Instrum.Meth. 676 (2012) 44-49, Nucl.Instrum.Meth. A743 (2014) 130-159

Scintillator tracker:Charged lepton: full kinematicsProton: full kinematics (full acceptance)

MINERvA

65

Outline







5. Summary

66


nuclear effects

nuclear targets

– quasielastic

– resonant


– Fermi motion


– C

– O

– Fe

– Pb

– Ar


Neutrino energy X

References: Phys.Rev. C94 (2016) no.1, 015503arXiv:1602.06730arXiv:1606.04403

67

Transverse kinematic imbalances– a neutrino shadow play

68

Source: http://zhejiangpiying.sokutu.com/tupian.html

To make Neutrino Shadow Play, we need ✔ beam of light✔ screen


69

To make Neutrino Shadow Play, we need ✔ beam of light → accelerator✔ screen



70

To make Neutrino Shadow Play, we need ✔ beam of light → accelerator✔ screen → transverse plane



71


Static nucleon target



72



Nuclear target


73


Nuclear target



74

Nuclear targetStatic nucleon target


75

● In given acceptance, overall spectral shapes not sensitive to FSIs.● Nuclear effects difficult to observe on top of neutrino-nucleon kinematics.

[arXiv:1608.04655]

MINERvA measurement of single-transverse kinematic imbalances

76

Total Solar eclipse 1999 in FranceBy Luc Viatour

77

● More sensitive to FSIs due to cancellation of nucleon level physics using kinematic imbalances

● Sensitivity achieved by dedicated momentum cuts and corrections.

[arXiv:1608.04655]

MINERvA measurement of single-transverse kinematic imbalances

78

Transverse Fermi motion

(transverse projected) momentum transfer in● initial-state multinucleon correlation, and● final-state interaction

T2K measurement of single-transverse kinematic imbalancesPreliminary, Progress reports:

arXiv:1605.00179, 1610.05077

79

Transverse Fermi motion

(transverse projected) momentum transfer in● initial-state multinucleon correlation, and● final-state interaction

Preliminary, Progress reports: arXiv:1605.00179, 1610.05077

T2K measurement of single-transverse kinematic imbalances

80

Fermi motion: flat



81

Transversely “accelerated” or “decelerated”

“acceleration”

FSI dynamics



82

“deceleration”“acceleration”


FSI dynamics



83

√


FSI dynamics

“deceleration”



84

● Large discrepancy between NEUT and GENIE➢ not seen in single-particle kinematics.

● Highlighted GENIE features (“collinear

enhancement”) all originate from its FSI model, see discussions in [Phys.Rev. C94 (2016) no.1, 015503]:

“the GENIE Collaboration suggested to investigate the effect of the elastic interaction of the hA FSI model.”



85

Outline







5. Summary

86


nuclear effects

nuclear targets

– quasielastic

– resonant


– Fermi motion


– C

– O

– Fe

– Pb

– Ar


Neutrino energy

X

87


nuclear effects

nuclear targets

– quasielastic

– resonant


– Fermi motion


– C

– O

– Fe

– Pb

– Ar


Neutrino energy

References: Phys.Rev. D92 (2015) no.5, 051302arXiv:1512.09042arXiv:1606.04403

H

With target,

Eν ∑ final-state energy.

A problem of .

=≠

Hnuclear

detector resolutionnuclear phy. + d.r.

88

● Pure hydrogen

– Technical requirement:

● bubble chamber (historical: 73, 79, 78, 82, 86)

– Safety issue: explosive

● “Since the use of a liquid H2 bubble chamber is excluded in the ND hall due to safety concerns, ...” [FERMILAB-PUB-14-022]

● In the last ~30 years there has been no new measurement of neutrino interactions on pure hydrogen.

Chin. Phys. C 38, 090001 (2014)

H2

89

Lepton-proton interaction → 3 charged particles: l p → l' X Y– Leading order realization in standard model:

Double-Transverse kinematic imbalance

90



91



92



93

Double-transverse momentum imbalance δpTT

● H: 0 ● Heavier nuclei: irreducible symmetric broadening

● by Fermi motion O(200 MeV)● further by FSI

● Hydrogen shape is only detector smearing. ● With good detector resolution, hydrogen yield can be extracted. ● With very good res., event-by-event selection of ν-H interaction is possible.

Phys.Rev. D92 (2015) no.5, 051302

94

● Aim at first neutrino-pure hydrogen cross section measurement since 1986✔ Signal shape well known from detector simulation. ✔ Background can be further constrained by single-transverse kinematic imbalances

and measurements w/ pure nuclear target, e.g. graphite.● Precise probe of nuclear effects in pion production via H/C cross section ratio: detector

systemic uncertainties largely canceled (as C, H in same molecule).

Work in progress, Progress reports: arXiv:1605.00154, 1610.06244

T2K measurement of double-transverse kinematic imbalances

95

arXiv:1512.09042

2× better tracking res.

✔ Requirement on nuclear physics decreases as resolution improves! Only need to look at |δp

TT|<O(10 MeV) region.

T2K performance projection

96

Ideal acceptance w/ ideal tracking+PID

3-particle final state: µ, p, π+

Eν reconstructed as sum of final-state energy

H excl. pπ+ signal ➢ Fraction: ~ 20% (blue-shifted peak) – 10% (tail)

Recipe for nuclear-free neutrino energy spectra

97




H excl. pπ+ signal ➢ Fraction: ~ 20% (blue-shifted peak) – 10% (tail)➢ No (nuclear) bias in reconstructed E

ν


98





ν➢ Can be extracted (statistically in realistic case)


99





ν➢ Can be extracted (statistically in realistic case)➢ σ only nucleon cross section, Φ=N/(σ ∆Ε

ν)

➔ both Φ and Eν nuclear-free

➔ require tracking, PID (only needed for Εν

calculation), νH excl. pπ+ x-sec


100






ν)





Same procedure for differential cross s

ections on W, Q

2 , etc.

101






ν)





Clean room for different exclusiv

e µpπ processes!

102

Outline







5. Summary

103

Summary (1)● NEW since 2016 summer:

– Doubled neutrino-mode statistics

– New reconstruction and event selection at SK: effective improvement in statistics by ~30%

– Improvements to neutrino interaction model

● Updated oscillation parameter estimates

– CP conserving values of δCP

are disfavored at 2σ level.

● T2K upgrade to collect 20×1021 POT and achieve 3σ (in case of favorable true values of δ

CP ) sensitivity to

exclude CP conserving values.

104

Summary (2)● It is important to understand nuclear properties in neutrino

interactions

– Future experiment requires total systematic errors better than few %.

● New technique to study nuclear and nucleon properties– Transverse kinematic imbalances

● correlation between final-state lepton and hadrons● Principle of solar eclipse: in the transverse plane, lepton kinematics is

used to cancel out nucleon level hadron kinematics; the rest is nuclear effects

– Single transverse kinematic imbalances: separate initial- and final-state nuclear effects

– Double transverse kinematic imbalance: modern measurement of ν-nucleon fundamental interaction

105

Source: http://www.cnhubei.com/ztmjys-pyts

谢谢 !

http://www.cnhubei.com/ztmjys-pyts

106

BACKUP

107

Impact of data-driven variation on sensitivity:

Will be addressed in future by 4π sample, hadronic recoil, ND upgrade

variation = pre-fit/model prediction difference at ND280

108

Quasi-elastic scattering (QE):

ω: energy transfer

109

Resonance production (RES):

ω: energy transfer

110

Deep inelastic scattering (DIS): nucleon breaks up

ω: energy transfer

111

ω: energy transfer

For QE and RES (nucleon not breaking up), ω “saturates” when E

ν > 0.5 GeV

[Phys.Rev. C94 (2016) no.1, 015503]

112

In QE and RES ● Lepton retains most of the increase of E

ν

● Leptonic kinematics much more Eν-dependent than

hadronic ones

Source: http://www.wikihow.com/Pump-a-Spalding-Neverflat-Basketball

ν

N

l'

For QE and RES (nucleon not breaking up), ω “saturates” when E

ν > 0.5 GeV

[Phys.Rev. C94 (2016) no.1, 015503]

ω: energy transfer

http://www.wikihow.com/Pump-a-Spalding-Neverflat-Basketball

113

END

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