Rocket experiment for Neutrino Decay Search

Overview

Yuji Takeuchi (Univ. of Tsukuba)Oct. 24, 2013

Neutrino Decay collaboration meeting

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Collaboration Members (Japan-US collab.: Search for Neutrino Decay)

• As of Oct. 2013

Japan Group Shin-Hong Kim, Yuji Takeuchi, Kenji Kiuchi, Kanai, Kazuki Nagata, Kota Kasahara, Ryuuya Ichimura, Takuya Okudaira, Kouya Moriuchi, Ren Senzaki (University of Tsukuba) , Hirokazu Ikeda, Shuji Matsuura, Takehiko Wada (JAXA/ISAS) , Hirokazu Ishino, Atsuko Kibayashi, Yasuki Yuasa(Okayama University) , Takuo Yoshida, Shota Komura, Ryuta Hirose(Fukui University) , Satoshi Mima (RIKEN), Yukihiro Kato (Kinki University) , Masashi Hazumi, Yasuo Arai (KEK)

US Group Erik Ramberg, Mark Kozlovsky, Paul Rubinov, Dmitri Sergatskov, Jonghee Yoo (Fermilab)

Korea Group Soo-Bong Kim (Seoul National University) 2

Cosmic neutrino background (CB)

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CMB𝑘𝑇

1MeV

CB

Motivation• Search for in cosmic neutrino background (CB)

– Direct detection of CB– Direct detection of neutrino magnetic moment– Direct measurement of neutrino mass:

• Aiming at sensitivity of detecting from decay for – Current experimental lower limit – SM expectation – L-R symmetric model (for Dirac neutrino) predicts

LRS: SU(2)L ｘ SU(2)R ｘ U(1)B-L

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𝑊 𝐿𝜈𝑖𝐿

γℓ 𝐿=𝑒𝐿 ,𝜇𝐿 ,𝜏 𝐿

𝜈 𝑗𝐿

𝜈𝑖𝑅𝑚𝜈𝑖

𝑊 1 𝜈𝑖𝑅

𝜈 𝑗𝐿ℓ 𝐿γℓ 𝑅𝑚𝜏

≃𝑊 𝐿+𝜁𝑊 𝑅

SM: SU(2)L ｘ U(1)Y

Suppressed by , GIM𝚪 (𝟏𝟎𝟒𝟑𝒚𝒓 )−𝟏 𝚪 (𝟏𝟎𝟏𝟕 𝒚𝒓 )−𝟏

Suppressed only by

1026 enhancemen

t to SM

Neutrino magnetic

moment term

PRL 38,(1977)1252, PRD 17(1978)1395

(𝑊 1

𝑊 2)=(c os 𝜁 −sin𝜁

sin𝜁 cos𝜁 )(𝑊 𝐿

𝑊 𝑅)

𝜈𝑖𝑅

𝜈 𝑗𝐿γ

Photon Energy in Neutrino Decay

m3=50meV

m1=1meV

m2=8.7meVE =4.4meV

ν3→𝜈1,2+𝛾 𝐸𝛾=𝑚3

2−𝑚1,22

2𝑚3

E =24meV

𝜈3

𝐸𝛾𝛾

𝜈2

Sharp Edge with 1.9K smearing

Red Shift effectd

N/d

E(A

.U.)

distribution in

meV]

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• From neutrino oscillation

• From CMB fit (Plank+WP+highL+BAO)

50meV<<87meV, 14~24meV51~89m

𝑚3=50meV

Feasibility of photon detection from CB decay

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Zodiacal LightZodiacal Emission

Su

rface b

rig

htn

ess

Galactic dust emission

Wavelength[m]

Integrated flux from galaxy counts

Galaxy evolution model

CIB measurements( AKARI, COBE)

Astrophys. J. 737 (2011) 2

Sharp edge with 1.9K smearing and energy resolution of a detector(0%-5%)

Red shift effect

Expected spectrum: and

CIB (fit from COBE data)

Differential photon energy spectrum from CB decay + CIB (w/ 2% energy resolution)Statistical uncertainties in are taken into account in the error bars

(eV)

CB decay

6.7 away from flat

Simulation(JPSJ 81 (2012) 024101)• If we assumed

– and r– No zodiacal foreground emission – 10 hour measurement– 20cm diameter and 0.1o viewing angle

telescope– A photon detector with 2% energy

resolution

We can detect photon from CB decay photon at 6.7 significance

𝒅𝑵𝜸

𝒅𝑬𝜸

−𝒅

𝒅𝑬𝜸( 𝒅𝑵𝜸

𝒅 𝑬𝜸)

Neutrino lifetime lower limit from AKARI data

𝑚3=50meV

𝑚3=50meV 150meV

x1012 yr

Fit CIB data to spectrum expected from decay assuming all contribution to CIB is only from decay

lifetime lower limit as a function of

Published in Jan. 2012

AKARI CIB data after subtracting foregrounds

Best fit spectrum from CB decay

Detector requirements• Requirements for detector

– Energy measurement for single photon with better than 2% resolution for (, far infrared photon)

– Rocket and satellite experiment with this detector

• Superconducting Tunneling Junction (STJ) detectors in development– Array of 50 Nb/Al-STJ pixels with diffraction grating covering

• For rocket experiment aimed at launching in 2016 in earliest, aiming at improvement of lower limit for by 2 order

– STJ using Hafnium: Hf-STJ for satellite experiment (after 2020)• : Superconducting gap energy for Hafnium• for 25meV photon: if Fano-factor is less than 0.3

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Zodiacal Light Zodiacal Emission

Su

rface b

rig

htn

ess

Galactic dust emission

Wavelength[m]

Integrated flux from galaxy counts

Galaxy evolution model

CIB measurements( AKARI, COBE)

Astrophys. J. 737 (2011) 2

FIR photon spectroscopy withdiffraction grating + Nb/Al-STJ array

Diffraction grating covering (16-31meV) Array of Nb/Al-STJ pixels: 50()x8()

We use each Nb/Al-STJ cell as a single-photon counting detector with extremely good S/N for FIR photon of

for Nb: if consider factor 10 by back-tunneling Expected average rate of photon detection is about 12KHz for 50pixels

Need to develop ultra-low temperature (2K) preamplifier In collaboration with Fermilab Milli-Kelvin Facility group (Japan-US

collaboration: Search for Neutrino Decay)

Nb/Al-STJ array

𝐸𝛾=16 31meVΔ𝜃

Assuming for STJ response time, requirements for STJ• Leak current <0.1nA

10Δ 𝜆

赤外線観測ロケットによる宇宙背景ニュートリノ崩壊探索

JAXA の CIBER 実験 ロケットで高度 200km~300km まで上昇．

約 5 分の観測 検出器，光学系，冷凍機の R&D 完了か

ら 2 年程度で打ち上げ可能 (2016 年~)

(16-31meV) の範囲で連続スペクトラムを測定 ( 回折格子で 50 分割 )

R&D 分光素子・光学系の設計 ロケット搭載クライオスタットの設計

(<0.9K) 3He sorption, or ADR

検出器，読み出し系， DAQ Nb/Al-STJ array 　 (leakage <0.1nA) 極低温アンプ (noise <16e, gain>1V/fC)

LHe 減圧 1.6K

分光・光学系

DAQ3He 減圧 <0.9K

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Backup

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Energy/Wavelength/Frequency

𝐸𝛾=25meV

𝜈=6THz𝜆=50𝜇𝑚

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Feasibility of FIR single photon detection

• Assume typical time constant from STJ response to pulsed light is ~1μs

• Assume leak current is 0.1nA

Fluctuation due to electron statistics in 1μs is

While expected signal charge for 25meV are

(Assume back tunneling gain x10)More than 3sigma away from leakage

fluctuation

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Feasibility of VIS/NIR single photon detection

• Assume typical time constant from STJ response to pulsed light is ~1μs

• Assume leakage is 160nA

Fluctuation from electron statistics in 1μs is

While expected signal for 1eV are (Assume back tunneling gain x10)

More than 3sigma away from leakage fluctuation

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CIB Experiment for Neutrino Decay Search with JAXA Rocket

Rate Calculation and Expected Lifetime Limit

• Rate/pixel = 　 0.7kHz at λ ＝ 40μm

• Measurements for 200 s → 　 140 k events /pixel 8 row　　 =1120k events/photon energy

黄道光（前景放射）

系外銀河 第一世代の星 ?

背景放射

CMB

DGL

FIR-rocketPhoton 数の統計エラーのみだとするとでの測定が可能

(CIB の寄与～ ) 先の論文よりもニュートリノ寿命の下限値をオーダー以上改善可能

λ ＝ 40 ～ 80μm