Download Many-body Physics in Neutrino Detection and Dark Matter Searches

Many-body Physics in Neutrino
Detection and DM Searches
Cheng-Pang Liu
National Dong Hwa University
May 19, 2017
PPP12, NCTU, Hsinchu
Collaborators
•
A collaboration consists of NP/HEP theorists, atomic
theorists, and experimentalists.
•
Core members: Jiunn-Wei Chen (NTU), Hsin-Chang
Chi (NDHU), CPL (NDHU), Lakhwinder Singh (AS),
Henry T. Wong (AS), Chih-Pan Wu (NTU)
•
Adjunct members: Keh-Ning Huang (Sichuan U.), ShinTed Lin (Sichuan U.), Qian Yue (Tsinghua, Beijing)
•
Supported in part by NCTS-ECP (2015-2018) and
MoST
Outline
•
Introduction
•
How Neutrino / DM Are Seen / Unseen
•
Why Low Energies?
•
Theory Basics
•
Selected Works
•
Summary
Introduction
1/, "Ê"9--9
/Ê ,Ê"1, 9Ê"Ê-
"6,9Ê /"Ê" Ê"Ê /1,½-Ê"-/Ê1-6Ê*,/
-
DNP/DPF/DAP/DPB
Joint Study on
the Future of Neutrino
Physics (2004)
Neutrino Physics
- An Interdisciplinary Study
DNP/DPF/DAP/DPB
Joint Study on
the Future of Neutrino
Physics (2004)
1/, "Ê"9--9
/Ê ,Ê"1, 9Ê"Ê-
"6,9Ê /"Ê" Ê"Ê /1,½-Ê"-/Ê1-6Ê*,/
-
+
+
Atomic Physics
…
Neutrino Physics
- An Interdisciplinary Study
3 Recommendations (APS 2004)
̣ A phased
program of sensitive searches for
neutrinoless nuclear double beta decay
̣ A comprehensive
U.S. program to complete our
understanding of neutrino mixing, to determine the
character of the neutrino mass spectrum and to search
for CP violation among neutrinos
•
Development of an experiment to make precise
measurements of the low-energy neutrinos from the
sun
How NP/AP Becomes Relevant?
•
As sources: beta decay, double beta decay, electron
capture …
•
As media: the Sun, supernovae, the Earth (atom. &
geo.) …
•
As detectors: neutrino-nucleus/atom scattering/capture
…
𝛘
+
+
Atomic Physics
…
Dark Matter Physics
- An Interdisciplinary Study, too!
WIMP Paradigm
PandaX-II (PRL 117, 121303, ’16)
LUX (PRL 118, 021303, ’17)
̣ Racing towards the “neutrino floor” !
How about “Light Dark Sector”?
•
•
Snowmass 2013 Rep. “Dark Sectors and New, Light,
Weakly-Coupled Particles” (arXiv:1311.0029), compelling cases:
•
Axions and Axion-Like Particles (<1eV)
•
Dark Photons (masses vary)
•
Light Dark Matter (sub-GeV, neutral/milli-charged)
Anomalies in X-ray (∼keV) and γ-ray (∼MeV–GeV) lines
indirectly point to potential LDM particles.
How NP/AP Becomes Relevant?
•
As detectors: DM-nucleus/atom scattering/capture …
•
As media: DM captured/boosted, decay/annihilate in
stellar environments …
•
As sources: dark bound states, mirror DM (dark nuclei,
atoms etc.) …
In this talk, focus on the
detector aspect in direct
detection
How They Are
Seen / Unseen?
For Neutrinos
Charged Current
Neutral Current
⌫e + (Z, A) ! e + . . .
⌫e + (Z, A) ! ⌫e + . . .
Depending on deposited E, final target states can be:
1. elastic (recoil)
2. excited (photon emission)
3. ionized (free e) / quasi-elastic (free p/n)
4. more complex configurations …
For Dark Matter
For Dark Matter
Similar to NC neutrino case
Direct Detector Classification
Important Issues
•
Can a scattering event be constructed as completely
as possible?
•
If not, how is a detector observable related to the
primary scattering event?
•
Is the primary event predicted by theory reliable?
Why Low Energies?
Where Interests Are
•
Solar, supernova, reactor, geo-neutrinos (keV-MeV)
•
Sterile neutrinos (eV or keV)
•
Relic neutrinos (sub-eV)
•
Light DM (sub-GeV)
Fluxes Are Big
Potential Enhancement / Filter
Nuclei and atoms have rich structure, e.g., each energy
level has its own specific quantum numbers, it can
provide potential
•
enhancement (resonance scattering …)
•
filter (selection rules in angular momentum, parity,
isospin …)
to experimental observables.
Important Physical Scales
•
For reactor/solar/supernova neutrinos:
E𝛎 ~ 100 keV - 20 MeV
•
Max. energy deposition by m𝛎 to mA:
2E𝛎2/(mA+2E𝛎) < 10 keV (if elastic)
•
•
Atomic scales with effective charge Zeff (shell-dep.):
pe ~ Zeff me𝛂, E𝝌 ~ Zeff me𝛂2, me𝛂 = 3.7 keV
Current lowest detector thresholds:
Tmin ~ keV (nuclear), ~100 eV (electronic)
Atomic effects important for low-E neutrino detection!
Important Physical Scales
•
For NR (v/c ~ 10-3), LDM (m𝝌 ≤ 10 GeV):
p𝝌 ≤ 10 MeV, E𝝌 ≤ 5 keV
•
Max. energy deposition by m𝝌 to mA:
4m𝝌mA/(m𝝌+mA)2 E𝝌 < 2 keV (if elastic)
•
Atomic scales with effective charge Zeff (shell-dep.):
pe ~ Zeff me𝛂, E𝝌 ~ Zeff me𝛂2, me𝛂 = 3.7 keV
•
Current lowest detector thresholds:
Tmin ~ keV (nuclear), ~100 eV (electronic)
•
Atomic effects important for LDM detection!
Theory Basics
What Are Needed?
•
•
•
•
HEP: 𝝂/𝝌-matter interaction (model-driven / EFT) 𝓛int
HEP/NP/AP: Differential cross section d𝝈/dT
⃗)
AstroP: 𝝂/𝝌 energy / velocity spectrum 𝝓(v
Exp-Th: Energy loss of 𝝂/𝝌 in detectors
Neutrino EM Interactions
•
General EM current for spin-1/2 particles:
charge
ত
ƚ
Ѣ‫ܖ^ ܜ‬ভ ^‫ܜ‬ѣ
ƚ
ଓ
ଓ
ম
Ê
‫ ܜ
ܡ‬ഡ۹଒ ‫ ܝ‬তভ ˥ ‫ܕ‬۹ଓ ‫ ܝ‬঴ভম ‫ܝ‬
۹۴
ଓ
ଓ
ദ
‫ ܝ ܝ‬ত
anapole
•
anomalous mag. dipole
ଓ
ম
ഩ
‫ܝ‬ভ তଖ ۹۸ ‫ ܝ‬঴ভম ‫ ܝ‬তଖ ത‫ܜ
ܡ‬
ভ˥‫ܝ‬
For 𝛎’s and q2=0:
F1=mQ; F2=MM; FA=AM; FE=EDM
el. dipole
EFT DM-matter Lagrangian
•
Leading-Order
LO
ǿint
•
೎
‫ܚܜܒܓ‬
SI
‫ ܓ‬ƒ
ഭ‫ܐ‬଒ স স
‫ܓ‬ƒ ‫ܓ‬
‫ ܓ‬
ܑ଒ ଓ সƒ স
‫ܓ‬ƒ ‫ܓ‬
‫ܝ‬
Next-to-Leading-Order O(q)
NLO
ǿint
೎
‫ܚܜܒܓ‬
‫ ܓ‬ƒ
঴‫ܓ‬
ഭ‫ܐ‬଒଑ স স
‫ܓ‬ƒ ‫ܕ‬ǖ
‫ ܓ‬
ܑ଒଑ ଓ সƒ স
‫ܓ‬ƒ ‫ܕ‬ǖ
঴‫ܓ‬
‫ܝ‬
SD
‫ ܓ‬ƒ ǖ
‫ܐ‬କ স ‫܆‬স স
Θ ‫ܓ‬ƒ ‫܆‬ǖ‫ܓ ܓ‬
‫ ܓ‬
ܑକ ଓ সƒ ‫܆‬ǖস স
‫ܝ‬
Θǖ
‫ ܓܝ‬
Θǖ
‫ ܓܝ‬
‫ ܓ‬ƒ
‫ܐ‬଒଒ স ‫ܕ‬ǖ
঴স
‫ ܓ‬
ܑ଒଒ ଓ সƒ ‫ܕ‬ǖ
঴স
‫ܝ‬
Θ ‫ܓ‬ƒ ‫܆‬ǖ‫ܓ ܓ‬റ
SR
LR
Θǖ
‫ܝ‬স
‫ܓ‬ƒ ‫ܓ‬
Θǖ
‫ܝ‬স
‫ܓ‬ƒ ‫ܓ‬റ ς
Refs: Fan et. al., JCAP11(2010) 042; Fitzpatrick et. al., JCAP02(2013) 004
Reaction Channels
•
•
•
•
Elastic: 𝝂/𝝌 + A → 𝝂/𝝌 + A (2-body)
Discrete excitation: 𝝂/𝝌 + A → 𝝂/𝝌 + A* (2-body)
Ionization: 𝝂/𝝌 + A → 𝝂/𝝌 + e- + A+ (3-body, our focus)
Channel separation is not trivial
Differential Cross Section
Example: a c1(e) type interaction with NR DM
ܑ঴^‫ܒ
ܐ‬
ଜ
ଔ‫ܗ‬
঱
ܑ
‫ܒ‬
ଓ
ଓ
೎ ೎^ Ѣ۹^‫ܐ‬଒ ল
ǖ
‫ۼ^ܝ‬ѣ ^ থ
‫ ˥ ܇‬۸CM ˥ ۸۹ ˥ ۸‫ ۼ‬
‫ܢ‬স ۹ ‫ۼ‬
঱ଔ
•
All dynamical information in response functions
•
ECM for CM recoil, EF-EI for internal state change
•
Biggest challenge: many-body wave functions for the
initial and final states
Baseline:
Free Electron Approximation
‫܍‬
ܑ঴
ܑ঴
ഋ
೎ ঩
‫ ˥ ܇‬۵‫ ܕ‬
ܑ‫ ܇‬FEA ‫ܕ‬଒
ܑ‫܇‬
T>Bi atomic shell open
଑
free scat.
•
No atomic calculation needed (almost)
•
Validity at sub-keV regimes needs justification
Our MB Approach: MCRRPA
An ab initio method improved upon Hartree-Fock theory
•
MC [multi-configuration]: open-shell atoms have more
than one ground-state configuration. Eg. for Ge:
^‫ ۽‬ѣ ଓ
‫ܐ‬଒ ^=<P?‫ܜ‬଒ଓ ѣ
ଓ
‫ܐ‬ଓ ^=<P?‫ܜ‬ଔଓ ѣ
•
R [relativistic]: Zα~0.25(Ge) / 0.4(Xe)
•
RPA [random phase approximation]: residual 2e
correlation is important for atomic excited / ionized
states
Benchmark: Ge Photoionization
σγ (Mb)
10
10
10
Rel. Diff. (%)
10
(PLB 731, 159, ’14)
1
0
-1
-2
10
5
0
-5
-10 1
10
MCRRPA
Exp. Fit
10
2
10
T (eV)
3
10
4
Benchmark: Ge Photoionization
σγ (Mb)
10
10
10
Rel. Diff. (%)
10
(PLB 731, 159, ’14)
1
0
-1
-2
10
5
0
-5
-10 1
10
MCRRPA
Exp. Fit
5% agreement!
10
2
10
T (eV)
3
10
4
Benchmark: Ge Photoionization
σγ (Mb)
10
10
10
Rel. Diff. (%)
10
(PLB 731, 159, ’14)
1
0
-1
-2
10
5
0
-5
-10 1
10
solid vs. atom
MCRRPA
Exp. Fit
5% agreement!
10
2
10
T (eV)
3
10
4
Benchmark: Xe Photoionization
Pr
el
im
in
ar
y
(arXiv:1610.04177)
Selected Works
Neutrino EM Moments
(PLB 731, 159, ’14; PRD 90, 011301(R), ’14; PRD 91, 013005, ’15)
•
Basic properties of elementary particles
•
Potential new physics
•
Implication for astrophysics & cosmology
Beauty of Low-T Detectors
•
•
Neutrinos scatter off free electron with energy
doposition T:
ܑ঴
ܑ‫܇‬
଑
W,CR
˰ ‫ ܇‬଑
Low threshold detectors:
MM
‫˥ ܇‬଒ mQ
‫˥ ܇‬ଓ
GEMMA: Ge @ 1.5 keV; TEXONO: Ge @ sub keV
•
Price to pay:
Atomic binding effects!
Ge AI by MM
MM: 2.9×10-11𝝁B
FEA overshoots
typical for reactor 𝛎’s
FEA works o.k.
Ge AI by mQ
typical for reactor
𝛎’s
-12
mQ = 1.0×10 e
FEA under!
EPA works o.k.
FEA overshoots
FEA works o.k.FEA better
Current Direct Limits
From PDG 2016
•
MM: 2.9×10-11𝝁B (GEMMA ’13); 7.4×10-11𝝁B (TEXONO ’07)
•
mQ: [1.5×10-12e (from GEMMA); 2.1×10-12e (from TEXONO)]
•
CR: 3.3×10-32cm2 (TEXONO ’10)
•
All with reactor anti-𝛎 sources
Current Direct Limits
From PDG 2016
•
MM: 2.9×10-11𝝁B (GEMMA ’13); 7.4×10-11𝝁B (TEXONO ’07)
•
mQ: [1.5×10-12e (from GEMMA); 2.1×10-12e (from TEXONO)]
•
CR: 3.3×10-32cm2 (TEXONO ’10)
•
All with reactor anti-𝛎 sources
Low-E Solar Neutrinos (arXiv:1610.04177)
More News from the Sun’s Core?
•
If yes, reporters are neutrinos. Photons are historians.
•
Low-E pp and 7Be neutrinos not precisely measured.
•
Standard Solar Model reaches 1% precision for PP
chain, will be nice to check experimentally.
•
Multi-ton-scale liquid xenon detectors are capable!
LUX-ZEPLIN Experiment
LUX-ZEPLIN Experiment
DARWIN Project
(European) Multi-purpose DM & neutrino experiments
with multi-ton scale liquid xenon
Solar Neutrino-Xenon Scattering
under revision !
Low-E Solar Neutrino Rate
Assume 1-ton liquid xenon & 1-year exposure
under revision !
FE overestimate!
Summary
Conclusions
•
Neutrino & DM physics is interdisciplinary.
•
Many-body physics is essential for sub-keV detectors
of neutrinos and dark matter.
•
High-quality many-body calculations can substantially
reduce theoretical errors.
•
Energy loss mechanism still needs better
understanding.
Thanks!
keV Sterile Neutrino (PRD 93, 093012, ’16)
Motivated by the 3.5 keV X-ray anomaly (Bulbul et al. & Boyarsky et al., ’14)
We consider:
trans. M1
rad. decay
ǿ ম‫ ܟ‬ম܎ ত non-standard int.
ভমsa ‫ ܒ‬
‫ ܒܙ‬
মÊ ܎ ঴ভম ম‫ܟ‬
ভম
۹
Interesting Kinematics
•
For active neutrino scattering (ma≈ma’≈0), Q2 < 0
•
For sterile-to-active transition (ms>0; ma≈0), Q2 can be
time-like (T→ms), and there is a cross over the real
photon point, Q2 = 0, when T ≈ ms/2
•
EM interaction ∝ 1/Q4, so d𝛔/dT enhanced near real
photon regime
𝛎s + Ge → 𝛎a +
ms=7.1keV, v/c=10-3
e
+
+
Ge
ms=20keV,v/c=10-3
Peak hight ∝ ms2; peak width ~ msv
Data Analysis w. TEXONO Data
139.3 kg-days, 500g Ge detector
Exclusion Plot of DM 𝛎s
10-13
Excluded Region
10-14
̣We got 2.5x10-14 𝝁B
sa
µν ( µB )
10-12
10-15
̣X-ray bound: 2.9x10-21 𝝁B
won w. huge detection volume
10-16 3
10
104
ms ( eV )
105