neutrino physics n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Neutrino Physics PowerPoint Presentation
Download Presentation
Neutrino Physics

Loading in 2 Seconds...

play fullscreen
1 / 34

Neutrino Physics - PowerPoint PPT Presentation


  • 121 Views
  • Uploaded on

Neutrino Physics. Member Eriko kusunoki Kenji shu Takeshi saito Mesanori iwamoto Mitsutaka nakao. NISHIMURA Group. CONTENTS. ν - Source. Theory of Neutrino Physics Super Kamiokande (Super K) Measuring Cosmic Rays T2K Experiment Analyzing T2K data. ν - Oscillation.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Neutrino Physics' - gavril


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
neutrino physics

Neutrino Physics

Member

Eriko kusunoki

Kenji shu

Takeshi saito

Mesanoriiwamoto

Mitsutakanakao

NISHIMURA Group

contents
CONTENTS

ν- Source

  • Theory of Neutrino Physics
  • Super Kamiokande (Super K)
  • Measuring Cosmic Rays
  • T2K Experiment
  • Analyzing T2K data

ν- Oscillation

ν- Detector

what is neutrino
What is neutrino?

・Three Flavors

・Neutral (no charge)

・Only Weak Interaction

・Very Tiny Mass

very difficult for detecting…

the interesting point is
The interesting point is…

Neutrino Oscillation

neutrino oscillation two mixing case
Neutrino Oscillation(Two mixing case)

・The mass basis is different from the interaction basis.

The probability to change νμinto ντis…

flavour

Θ:mixing angle

L : Length [km]

E : energy[GeV]

Δm2 : mass square difference[eV2]

mass

but nature is more complex…

neutrino oscillation three mixing case
Neutrino Oscillation(Three mixing case)

~45°

~34°

Atmospheric Neutrinos

νμ→ντ

Solar Neutrinos

νe→νx

Accelerator

νμ→νe

What we want to know is …

T2K

Mixing Parameter

cp violation what is cp in pmns matrix
CP violation~What is δCP in PMNS matrix?~

This parameter leads to CP violation.

Leading Term

CP term

how can we detect neutrinos
How can we detect neutrinos?

The answer is…

Super K

slide10

Super-Kamiokande

Kamioka

1km

Inner tank

11,129 PMTs (50cm)

detect neutrinos.

1km Underground

We can block muonsthat originate from cosmic ray.

41.4m

outer tank

  • 1,885 PMTs (20cm)
  • distinguish neutrinos from muons coming from outside.

water

39.3m

50,000 t

slide11

Neutrino detection @Super-Kamiokande

inverse beta decay

Neutrinos interact with particle in water.

O

n

p

  • → SK detect Cherenkov light that is created when a charged particle travels faster than the speed of light in water.

Cherenkov light

H

neutrino

Blue : weak light

Vertex

Timing ofdetection

Vertex position

Finding Cherenkov ring

Neutrino traveling direction and energy

Red : strong light

Event display

slide12

Neutrino detectors

Super-Kamiokande

Next: Hyper-Kamiokande

Metal dynode

Improving performance

(Volume of tank) ×25

  • PMT (PhotoMultiplier-tube)
  • HPD (Hybrid-Photo‐Detector)

To measure the light energy, we use PMTs.

HK might uses HPDs instead of PMT.

Let’s use HPD !!!!

~2kV

Photon

photoelectric effect

Avalanche diode

HPD accomplish superior performance in low cost !!

~8kV

slide13

Testing PMTs and HPDs

ThesePMT are used in super-K

to measure the cosmic rays.

HPDs may be used in

Hyper-K .

We tested an HPD and a PMT

to measure the angular

Distribution of cosmic ray muons .

PMT

HPD

slide14

The Angular Distribution of Cosmic ray Muons

The flux is given by

J(x,θ) = J(x,0) (n =

Where λ is mean free path

The purpose of this

experiment was

finding the value of n.

slide15

μ

Scintillator(50cm×50cm)

Set up

We used two sets of two

detectors to measure

the angular distribution.

Scintillator(20cm×20cm)

HPD

PMT

PMT

First detector

Second detector

slide16

We made a coincident

circuit to count muons

which activated all

detectors.

slide17

Results

We corrected flux by a solid angle

slide18

fitting

We fitted a× and determined

n = 2.470.53 .

what is t2k
What is T2K?
  • Tokai(J-PARC) to Kamioka(SK)
  • Pure
  • SK can distinguish and
  • Observe appearing and disappearing

?

http://t2k-experiment.org/ja/

devices to discovery
Devices to discovery
  • Distance
  • Off axis

(on axis)

2.5

appearensae

in E = 0.6 GeV

disappearing in L =295 km

SK

L = 295 km

E ~ 0.6 GeV

enrichment signals
Enrichment signals
  • Selection one ring -like events
  • Reduce BG cuts using Monte Carlo calculations

377 events is first selected by timing

60

193

Number of rings

e -like evernts

cut NC,μ

cut BG

cut collapse π,μ

cut in beam

57 44 39 28

events
events

-like single ring events were found

  • Proton created in J-PARC :
  • expected BG : 4.92
  • So we calculate expectation and estimate

Was happened?

?

6.57

what we have
What we have
  • T2K result

number :

Proton number :

Very new :

Physical Review Letters, 2014 Feb

  • Theory
maximum likelihood method to find
Maximum Likelihood Method to find
  • Likelihood function : ← maximize L
  • ← minimize

Compare numbers obs. vs exp.

Poisson distribution

Restrict systematic parameters

f : systematic errors ← parameters

Expectation of numbers observed

: signal of oscillation depends on ←par

: background appeared as by M.C. simulation (depends on , , , function was given)

slide28
Get
  • Best fit

Change minimizing

That = experimental result!!!

get errors
Get errors
  • Error(1 sigma)

get at

get confidence level for
Get confidence level for

get at

Significance : 6.9s

actually exists and non-zero!!!

comparison with actual t2k
Comparison with actual T2K

Actual T2K

Our verification

C.L. :

  • C.L. :

Same value, same error

T2K was correct!!!

(C.L. is better by using energy likelihood function)

in actual t2k experiment
In actual T2K experiment…
  • Likelihood function

: oscillation parameter : systematic error parameter

f are more than 49!

future experiment
Future experiment
  • T2K is just in beginning
  • Continue to get 10 times more data
  • Check the sensitivity ()

(We did)

→ twice more precise

  • Anti-Neutrino experiment by Hyper-K

can measure

summary
Summary

Experiment

Analyzing

Theory