dark matters and neutrino projects at the center for underground physics
DESCRIPTION
Yeongduk Kim Center for Underground Physics, IBS Sejong University. Dark MAtters and Neutrino Projects at the Center for Underground Physics. AKPA. 2014. 5 . 9 . Center for Underground Physics (CUP ). CUP began on July 2013 as a headquarter center. - PowerPoint PPT PresentationTRANSCRIPT
DARK MATTERS AND NEUTRINO PROJECTS AT THE CENTER FOR
UNDERGROUND PHYSICS.
AKPA
Yeongduk KimCenter for Underground Physics, IBS
Sejong University
2014. 5. 9.
2Center for Underground Physics (CUP)
CUP began on July 2013 as a headquarter center.
Now, 17 Ph.Ds, 15 students, 3 technicians, 2 administrations.
Research Area : Dark Matter, Double Beta Decay, Sterile neutrino
search, Low temperature Detector Development.
3Evidences for Dark Matter Existence
4More quantitative evidence : cosmic microwave background
5Particle candidates
Many particle candidatesare proposed with many orders of magnitude of mass.
Who will be the hero ? Or None of them.
K.Y. Choi, JKPS 63, 1685(2013)
6Weakly Interacting Massive Particle (WIMP)
WIMP is a massive new particle having a right <sv> value for the current dark matter density. So it is a good candidate for dark matter particles.
increasing
7WIMP DETECTION
c c
q q
Annihilation
(Indirect Search)
WIMP scattering(Direct Search)
Pro
duct
ion
(Acc
eler
ator
Sea
rch)
WIMP
Nucleus Nucleusc c
8Detection Principle of Direct Search
Detector
WIMP
Nucleus
0 , ,W DM
WIMP-Nucleus elastic scattering Event rate : ExperimentMeasure this
SUSY models
Limit of R Limit of s
9What is the direct signal for WIMPs ?
1. Recoil energy spectrum as expected at low energy.2. Annual modulation.3. Directional asymmetry.4. A2 dependence (Spin-independent)
Earth velocity (30km/s)
Yearly revolution annual modulation Daily rotation direction change
10
250 kg NaI(Tl) crystals coupled with PMTs.Observed clear annual modulation for 13 years.
PMT+HV divider
DAMA/LIBRA experiment
11Status of WIMP searches
YangYang Pumped Storage Power Plant
YangYang(Y2L) Underground Laboratory
Minimum depth : 700 m / Access to the lab by car (~2km)
(Upper Dam)
(Lower Dam)
(Power Plant)
KIMS (Dark Matter Search)AMoRE (Double Beta Decay Experiment)
SeoulY2L
700m
1000m
RENO
13KIMS-NaI Experiment @ CUP
• To verify the DAMA result using same NaI(Tl) crystals.• Our strategy : Achieve lower background level and lower energy threshold than DAMA by factor 2.• We can clarify the origin of the annual modulation unambiguously.
NaI(Tl) Crystal
CsI Detector
14Background rates – We are getting there.
• Low threshold down to 1 keV is possible.• Background reduction expected by further purification.
Search for Neutrinoless Double Beta Decays
Ettore Majorana (1906 – 1938 ?)
16Neutrino mixing & oscillation
16
If neutrinos are massive and mixed, then they oscillate.
12
3
1 ?m
m
0
12
3
m
0
17Neutrino mixing & oscillation
17
2
2 2 2 2 2 2 22 1
( )1 sin 2 sin 1.27 ( ) , ( )
tP
L kmm eV m m mE GeV
Survival Probability
PRL100, 221803 (2008)
18
Search for Neutrinoless double beta decay (0bb)
Observation of 0bb will prove
0bb eventb b
19
Neutrino mass from 0bb experiment
Half-lifves of 0bb inversely proportional to mass2
Half-lifeMeasured
Neutrino Mass
Moore’s law for 0bb ?Elliott & Vogel, Ann, Phys. (2002)
76Ge, Gerda (0.3) 2013.9136Xe, EXO (0.26) 2012.7
136Xe, KAMLAND-ZEN (0.19) 2013.2
21Overview of AMoRE-200kg
Scintillating Bolometer : 40Ca100MoO4 + MMC
CaMoO4
Light sensorMMC
MMC phonon sensor
<10-50 mK>
AMoRE-200 is the most massive experiment with enriched isotope having Q value > 3MeV.
216 g<Now, 2013>
<2018>
22
MMC (Metallic Magnetic Calorimeter)
paramagnetic sensor: Au:Er
23
Energy resolution data
CaMoO4(natural) with a phonon sensor only.
<2013 KRISS>
FWHM = 9 keV, Goal = 5 keV
24Crystal Growing Facility
Motivation : difficulty to find a reliable and economical company.Will develop chemical purification and crystallization ourself in-side the center. (4 furnaces)
25
Races for 0bb
Thank you !
27
Dark M
atter Group
New
Detector G
roup
Low
Temp. D
etector Group
Double B
eta Decay G
roup
Nuclear A
strophysics Group
Director
Y2L
KT1 LAB
Simulation Team
SBL Team
KIMS-NaI Team
Advisory Committee
Underground Lab Preparation Team
Administration
KRISS
Samcheok City
KIMS Collaboration
New Physics Team
Adjunct group
AMoRE Collaboration
Organization of CUP
28
Weakly Interacting Massive Particles (WIMP)이휘소 , 와인버거 박사의 1977 논문 “Cosmological Lower Bound on Heavy-Neu-trino Mass” ( 무거운 중성미자 질량에 대한 우주론적인 하한값 )암흑물질의 후보로서의 약하게 상호작용하는 윔프와 같은 무거운 입자의 가능성을 거론 .
빅뱅이후 약하게 상호작용하는 안정적인 입자가 생성되어 Freeze out 되어 남게 되면 Dark Matter 가 될수 있다 .M(wimp)>2GeV
29
2 Jun.
Time
Back
grou
nd L
evel
KIMS-CsI annual modulation data
• 12 crystals (104.4kg).• 2.5 year data (Sep. 2009–Feb. 2012)• Background Level : 2~3 cpd/kg/keV The mean amplitude from 3 keV to 6 keV is
0.0008±0.0068 cpd/kg/keV
31Comparison with Direct Search
32PMT noise reduction in background data.
DAMA/LIBRA reported PMT noise reduction by introducing charge ratio parameters. KIMS-NaI obtained the same results as DAMA.
X1X2
X1X2
DAMA, E=2-4 keV KIMS-NaI, E=2-4 keV
PMT noise
Real signals
33Q|fermion> = |boson>particle super particleR parity = 1 for ordinary particles = -1 for SUSY partners
If R parity is conserved, LSP ( Lightest SUSY Partner) will be stable and a strong candidate of WIMP.
2 3( 1) j B LR
Supersymmetric particles
AMoRE 10
AMoRE 200
Effec
tive
Neu
trin
o m
ass
(eV
)
Lightest neutrino mass (eV)
Toward low
er neutrino mass
35
Pulse Shape Discrimination
Muon
Gamma
Alpha
and b events show different pulse shapes in phonon signals.
Beta-Alpha
36
Phonon sensor for AMoRE
Gold film
We measure both thermal and athermal
phonons.
Phonon collec-torPatterned gold film
Gold wires(thermal connec-
tion)
MMC
rise-time: ~ 0.5ms
<Heat flow optimization>
216 g CaMoO4