1
Lecture VIII: Cosmic Frontier Connections
ACFI NLDBD School 10/31-11/3 2017!
M.J. Ramsey-Musolf U Mass Amherst
http://www.physics.umass.edu/acfi/
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Lecture VIII Goals
• Provide some background on leptogenesis in the broader context of baryogenesis
• Discuss some implications of 0νββ-decay searches for leptogenesis
• Provide some background on cosmological probes of neutrino mass**
• Invite questions !
** Disclaimer: not my primary area of expertise
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Lecture VIII Outline
I. Origin of Matter: Leptogenesis
II. Neutrino Mass from Cosmology
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I. Origin of Matter: Leptogenesis
Symmetries & Cosmic History
Standard Model Universe
EW Symmetry Breaking: Higgs
QCD: n+p! nuclei
QCD: q+g! n,p…
Astro: stars, galaxies,..
10-35 s
10-11 s 10-5 s
~ 1 m
380k yr
Symmetries & Cosmic History
Standard Model Universe
EW Symmetry Breaking: Higgs
BSM Physics?
QCD: n+p! nuclei
QCD: q+g! n,p…
Astro: stars, galaxies,..
10-35 s
10-11 s 10-5 s
~ 1 m
380k yr
The Origin of Matter
Explaining the origin, identity, and relative fractions of the cosmic energy budget is one of the most compelling motivations for physics beyond the Standard Model
Cosmic Energy Budget
Dark Matter
Dark Energy
68 %
27 %
5 %
Baryons Baryons
The Origin of Matter
Explaining the origin, identity, and relative fractions of the cosmic energy budget is one of the most compelling motivations for physics beyond the Standard Model
Cosmic Energy Budget
Dark Matter
Dark Energy
68 %
27 %
5 %
Baryons Baryons
Cosmic Baryon Asymmetry
Big Bang Nucleosynthesis:
Light element abundances depend on YB
Cosmic Microwave Bcknd:
Shape of anisotropies depends on YB
uILi = (Su)ij umass
Lj (49)
uIRi = (Tu)ij umass
Rj (50)
dILi = (Sd)ij dmass
Lj (51)
dIRi = (Td)ij dmass
Rj (52)
VCKM
= S†uSd (53)
V LCKM
= S†uSd (54)
(55)
V RCKM
= T †uTd (56)
V RCKM
= T †uTd (57)
H1�body
=GFp
2
⌘
2mN
~� · ~r ⇢(~r) (58)
⌘ / GF sin � sin ✓1
sin ✓2
sin ✓3
(59)
dA(199Hg) = S S
(60)
= 2.8⇥ 10�4 fm�2
(61)
S = �1.4⇥ 10�8 e� fm3
YB =nB
s= (8.59 ± 0.11)⇥ 10�11
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Symmetries & Cosmic History
Standard Model Universe
EW Symmetry Breaking: Higgs
QCD: n+p! nuclei
QCD: q+g! n,p…
Astro: stars, galaxies,..
10-35 s
10-11 s 10-5 s
~ 1 m
380k yr
How did we go from nothing to something ?
BSM Physics?
Ingredients for Baryogenesis
• B violation (sphalerons)
• C & CP violation
• Out-of-equilibrium or CPT violation
Ingredients for Baryogenesis
• B violation (sphalerons)
• C & CP violation
• Out-of-equilibrium or CPT violation
Standard Model BSM
✔
✖
✖
✔
✔
✔
Ingredients for Baryogenesis
• B violation (sphalerons)
• C & CP violation
• Out-of-equilibrium or CPT violation
Standard Model BSM
✔
✖
✖
✔
✔
✔
Scenarios: leptogenesis, EW baryogenesis, Afflek-Dine, asymmetric DM, cold baryogenesis, post-sphaleron baryogenesis…
Symmetries & Cosmic History
Standard Model Universe
EW Symmetry Breaking: Higgs
QCD: n+p! nuclei
QCD: q+g! n,p…
Astro: stars, galaxies,..
?
Baryogenesis: When? CPV? SUSY? Neutrinos?
10-35 s
10-11 s 10-5 s
~ 1 m
380k yr
Symmetries & Cosmic History
Standard Model Universe
EW Symmetry Breaking: Higgs
QCD: n+p! nuclei
QCD: q+g! n,p…
Astro: stars, galaxies,..
?
Baryogenesis: When? CPV? SUSY? Neutrinos?
EW Baryogenesis: testable w/ EDMs + colliders
10-35 s
10-11 s 10-5 s
~ 1 m
380k yr
Leptogenesis: look for ingred’s w/ νs: DBD, ν osc
Baryogenesis Scenarios E
nerg
y S
cale
(GeV
)
1012
Affleck Dine 109
10 2 10-1
Standard thermal lepto
Electroweak, resonant lepto, WIMPY baryo, ARS lepto…
Post-sphaleron, cold…
16
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What Questions Does It Address ?
• Is the neutrino its own antiparticle ?
• Why is there more matter than antimatter ?
• Why are neutrino masses so small?
New heavy neutrino-like particle = its own anti-particle
“See saw mechanism” “Leptogenesis”
Heavy neutrino decays in early universe generate baryon asym
ν = ν
Neutrinos and the Origin of Matter
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m2 ⇡MN (37)
�(N ! `H) 6= �(N ! ¯`H⇤) (38)
4
• Heavy neutrinos decay out of equilibrium in early universe
• Majorana neutrinos can decay to particles and antiparticles
• Rates can be slightly different (CP violation)
• Resulting excess of leptons over anti-leptons partially converted into excess of quarks over anti-quarks by Standard Model sphalerons
Neutrinos and the Origin of Matter
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m2 ⇡MN (37)
�(N ! `H) 6= �(N ! ¯`H⇤) (38)
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• Heavy neutrinos decay out of equilibrium in early universe
• Majorana neutrinos can decay to particles and antiparticles
• Rates can be slightly different (CP violation)
• Resulting excess of leptons over anti-leptons partially converted into excess of quarks over anti-quarks by Standard Model sphalerons
Neutrinos and the Origin of Matter
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• Heavy neutrinos decay out of equilibrium in early universe
✓MX
�M
◆>> 1 (79)
gX << 1 (80)
U↵N ⇠ mD
MN
(81)
U↵N ⇠r
vL
vR
� m⌫
MN
(82)
+⇣NR, NR
⌘(83)
�L =
✓�+
p2 �+
�0 ��+
p2
◆(84)
mL ⇠ ghL h�0
Li (85)
mN ⇠ ghR h�0
Ri (86)
�N ⌘ �(NR ! `H) + �(NR ! ¯H⇤) =|h|28⇡
MN (87)
�N(z) =K
1
(z)
K2
(z)�N (88)
H(T ) ⇠ 1.66 g⇤T 2
MP
(89)
�(`H ! NR)
MN
(90)
H(T )
MN
(91)
7
NR
H
l h
Hubble rate
✓MX
�M
◆>> 1 (79)
gX << 1 (80)
U↵N ⇠ mD
MN
(81)
U↵N ⇠r
vL
vR
� m⌫
MN
(82)
+⇣NR, NR
⌘(83)
�L =
✓�+
p2 �+
�0 ��+
p2
◆(84)
mL ⇠ ghL h�0
Li (85)
mN ⇠ ghR h�0
Ri (86)
�N ⌘ �(NR ! `H) + �(NR ! ¯H⇤) =|h|28⇡
MN (87)
�N(z) =K
1
(z)
K2
(z)�N (88)
H(T ) ⇠ 1.66 g⇤T 2
MP
(89)
�(`H ! NR)
MN
(90)
H(T )
MN
(91)
7
+ NR
H*
l h
_
Neutrinos and the Origin of Matter
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• Heavy neutrinos decay out of equilibrium in early universe
Simple estimation
2 4 6 8 10
0.2
0.4
0.6
0.8
✓MX
�M
◆>> 1 (79)
gX << 1 (80)
U↵N ⇠ mD
MN
(81)
U↵N ⇠r
vL
vR
� m⌫
MN
(82)
+⇣NR, NR
⌘(83)
�L =
✓�+
p2 �+
�0 ��+
p2
◆(84)
mL ⇠ ghL h�0
Li (85)
mN ⇠ ghR h�0
Ri (86)
�N ⌘ �(NR ! `H) + �(NR ! ¯H⇤) =|h|28⇡
MN (87)
�N(z) =K
1
(z)
K2
(z)�N (88)
H(T ) ⇠ 1.66 g⇤T 2
MP
(89)
�(`H ! NR)
MN
(90)
H(T )
MN
(91)
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ΓN (z
) / Γ
N
z = MN / T
ΓN < H(T=MN )~
Neutrinos and the Origin of Matter
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• Heavy neutrinos decay out of equilibrium in early universe
Simple estimation
Lmass
=�
⌫L NCR
� ✓0 mD
mD MN
◆ ✓⌫L
NR
◆(37)
m1
⇡ m2
D
MN
(38)
m2
⇡ MN (39)
Lmass
=�
⌫L NCR
� ✓0 mD
mD MN
◆ ✓⌫L
NR
◆+ mL⌫C
L ⌫L (40)
Lmass
=�
⌫L NR NCS
�0
@0 mL
D 0mL
D 0 MRD
0 MRD µ
1
A
0
@⌫L
NR
NS
1
A (41)
m⌫ ⇠ mLD
�MR
D
��1
µ�MR
D
��1
mLD (42)
�(N ! `H) 6= �(N ! ¯H⇤) (43)
Lmass
= yLHNR + h.c. + MNNCR NR (44)
Lmass
=y
⇤LcHHT L + h.c. (45)
�(NR ! `H) 6= �(NR ! ¯H⇤) (46)
m⌫ =m2
D
MR
(47)
hp0| JEM
µ |pi = U(p0)
F
1
�µ +iF
2
2M�µ⌫q
⌫ +iF
3
2M�µ⌫�5
q⌫ +FA
M2
(q2�µ � 6qqµ)�5
�U(p) (48)
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m⇤ = 8⇡ ⇤ (1.66g⇤)v2
MP
(92)
8
~ few x 10-3 eV
m⇤ = 8⇡ ⇤ (1.66g⇤)v2
MP
(92)
m1
⇡ m⇤ (93)
8
ΓN < H(T=MN )~
Neutrinos and the Origin of Matter
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• Heavy neutrinos decay out of equilibrium in early universe
Washout processes
NR
H * H
l l _
ΔL = 2
Neutrinos and the Origin of Matter
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• Heavy neutrinos decay out of equilibrium in early universe
Complete calculation: Boltzmann equations
di Bari ‘12
Non-Eq: T < mN
Eq: T > mN
Neutrinos and the Origin of Matter
25
m2 ⇡MN (37)
�(N ! `H) 6= �(N ! ¯`H⇤) (38)
4
• Heavy neutrinos decay out of equilibrium in early universe
• Majorana neutrinos can decay to particles and antiparticles
• Rates can be slightly different (CP violation)
• Resulting excess of leptons over anti-leptons partially converted into excess of quarks over anti-quarks by Standard Model sphalerons
Neutrinos and the Origin of Matter
26
m2 ⇡MN (37)
�(N ! `H) 6= �(N ! ¯`H⇤) (38)
4
• Heavy neutrinos decay out of equilibrium in early universe
• Majorana neutrinos can decay to particles and antiparticles
• Rates can be slightly different (CP violation)
• Resulting excess of leptons over anti-leptons partially converted into excess of quarks over anti-quarks by Standard Model sphalerons
Neutrinos and the Origin of Matter
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CPV Asymmetry
Tree-level CPV One-loop “absoprtive part” X
Buchmuller, Peccei, Yanagida ‘05
Neutrinos and the Origin of Matter
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CPV Asymmetry
Tree-level CPV One-loop “absoprtive part” X
Buchmuller, Peccei, Yanagida ‘05
CPV phases but not same as φPMNS
Neutrinos and the Origin of Matter
29
Putting pieces together: B-L asymmetry
Buchmuller, Peccei, Yanagida ‘05
Neutrinos and the Origin of Matter
30
m2 ⇡MN (37)
�(N ! `H) 6= �(N ! ¯`H⇤) (38)
4
• Heavy neutrinos decay out of equilibrium in early universe
• Majorana neutrinos can decay to particles and antiparticles
• Rates can be slightly different (CP violation)
• Resulting excess of leptons over anti-leptons partially converted into excess of quarks over anti-quarks by Standard Model sphalerons
Electroweak Sphalerons
31
Aλ
Sphaleron Configuration
Electroweak Sphalerons
32
Aλ
Sphaleron Configuration Δ (B+L) / NFAnomaly
Electroweak Sphalerons
33
Aλ
Sphaleron Configuration Δ (B+L) / NFAnomaly
EW sphalerons convert B-L asymmetry to YB
Davidson-Ibarra Bound
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m⇤ = 8⇡ ⇤ (1.66g⇤)v2
MP
(92)
m1
⇡ m⇤ (93)
1
T1/2
= G0⌫(E,Z) |M0⌫ | |hm��i|2 (94)
Lfs
/ m�1/2
⌫ (95)
|✏1
| <⇠3
8⇡
MN1
m⌫3
hH0i2 (96)
8
MN1 > 109 GeV ~
Davidson, Ibarra ‘02
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TeV Scale LNV ?
€
e−
€
e−
€
A Z,N( )
€
A Z − 2,N + 2( )
TeV LNV Mechanism
Dirac Majorana
O5 =
��H
⇤
�� H†H (25)
M⌃± �M⌃0 ⇠ ↵
4⇡MW (26)
L =
g
2
hij
⇥¯LCi"�LLj
⇤+ (L$ R) + h.c. (27)
�����Qe
W
QeW
���� = 0.14
|hee|2(M�/1 TeV)
2 (28)
|Vud|2 + |Vus|2 = |Vud|21 +
|Vus|2|Vud|2
�(29)
Lmass = y ¯L ˜H⌫R + h.c. (30)
Lmass =
y
⇤
¯Lc˜H ˜HT L + h.c. (31)
3
O5 =
��H
⇤
�� H†H (25)
M⌃± �M⌃0 ⇠ ↵
4⇡MW (26)
L =
g
2
hij
⇥¯LCi"�LLj
⇤+ (L$ R) + h.c. (27)
�����Qe
W
QeW
���� = 0.14
|hee|2(M�/1 TeV)
2 (28)
|Vud|2 + |Vus|2 = |Vud|21 +
|Vus|2|Vud|2
�(29)
Lmass = y ¯L ˜H⌫R + h.c. (30)
Lmass =
y
⇤
¯LcHHT L + h.c. (31)
�(⌫R ! `H) 6= �(⌫R ! ¯`H⇤) (32)
m⌫ =
m2D
MR
(33)
3
33
F
B B
O(1) for Λ ~ 1 TeV
Implications
TeV LNV & Leptogenesis E
nerg
y S
cale
(GeV
)
1012
10 3
10 2 10-1
Standard thermal lepto
Fast ΔL = 2 int: erase L
36
Deppisch et al ‘14, ‘15
TeV LNV & Leptogenesis E
nerg
y S
cale
(GeV
)
1012
10 3
10 2 10-1
Standard thermal lepto
Electroweak, resonant lepto, WIMPY baryo, ARS lepto…
Post-sphaleron, cold…
Baryogenesis alternatives 37
Fast ΔL = 2 int: erase L Deppisch et al ‘14, ‘15
38
Low Scale “ARS” Leptogenesis
Akhmedov, Rubakov, Smirmov ‘98
1. 3 Singlet RH neutrinos: NA , NB , NC
2. LTOT = LSM + LA + LB + LC
3. Nk oscillations + CPV ! LA = 0, LA = 0, LA = 0 but LTOT =0
4. Yukawa interactions: Lk , H + lk in equilibrium above TEW for k=A,B but not for k=C
5. Lepton number for lA,B converted to nB by EW sphalerons
6. Conditions 4 ! MNk can be ~ O( GeV )
/ / /
39
Low Scale “ARS” Leptogenesis
M. Drewes
40
II. Neutrino Mass from Cosmology
41
ACFI Workshop
December 2015
42
0νββ-Decay: Standard MechanismThree active light neutrinos
Effe
ctiv
e D
BD
neu
trino
mas
s (e
V)
Inverted Normal
Lightest neutrino mass (eV) !
43
0νββ-Decay: Standard Mechanism Three active light neutrinos
Effe
ctiv
e D
BD
neu
trino
mas
s (e
V)
Inverted Normal
Current generation Current generation
Ton Scale
Lightest neutrino mass (eV) !
44
0νββ-Decay: Standard Mechanism Three active light neutrinos
Effe
ctiv
e D
BD
neu
trino
mas
s (e
V)
Inverted Normal
Ton Scale
Full implications require information on lightest mass & hierarchy
Lightest neutrino mass (eV) !
Current generation Current generation
45
Interpreting a Positive Result Three active light neutrinos
Effe
ctiv
e D
BD
neu
trino
mas
s (e
V)
Inverted Normal
Ton Scale
Positive result would be consistent with 3 light active ν’s & IH or quasi-deg regime, but not definitive as to mechanism
Lightest neutrino mass (eV) !
Current generation Current generation
46
Interpreting a Null Result: St’d Mechanism Three active light neutrinos
Effe
ctiv
e D
BD
neu
trino
mas
s (e
V)
Inverted Normal
Ton Scale
Full implications require information on lightest mass & hierarchy
Lightest neutrino mass (eV) !
Current generation Current generation
47
Kinematic Neutrino Mass Measurements
KATRIN 3H ! 3He e- ν _
48
St’d Mech: What Would a Null Result Imply ? Three active light neutrinos
Effe
ctiv
e D
BD
neu
trino
mas
s (e
V)
Inverted Normal
Ton Scale
3H decay cur gen
Null result in NLDBD & non-zero mν from 3H decay ! Neutrinos are (pseudo) Dirac
Lightest neutrino mass (eV) !
Current generation Current generation
49
St’d Mech: What Would a Null Result Imply ? Three active light neutrinos
Lightest neutrino mass (eV) !
Effe
ctiv
e D
BD
neu
trino
mas
s (e
V)
Inverted
Ton Scale
3H decay cur gen
Normal
3H decay next gen
Current generation Current generation
Null result in NLDBD & non-zero mν from 3H decay ! Neutrinos are (pseudo) Dirac
50
St’d Mech: What Would a Null Result Imply ? Three active light neutrinos
Lightest neutrino mass (eV) !
Effe
ctiv
e D
BD
neu
trino
mas
s (e
V)
Inverted
Ton Scale
Normal
Current generation Current generation
Null result in NLDBD & non-zero mν from 3H decay ! Neutrinos are (pseudo) Dirac
3H decay cur gen
3H decay next gen
P. Vogel
51
Neutrino Mass & Cosmology
Matter Power Spectrum
Transition to non-rel ν matter
Massive neutrinos suppress power (relative to large scale power) at scales below free streaming scale K. Abazajian ACFI neutrino mass workshop
Σ mv < 0.12 eV
52
Neutrino Mass & Cosmology
Matter Power Spectrum
K. Abazajian ACFI neutrino mass workshop
J. Brau, U. Oregon
Later Earlier
53
Neutrino Mass & Cosmology
Matter Power Spectrum
K. Abazajian ACFI neutrino mass workshop
Later Earlier
Neutrino Free Streaming
ΩM = Ων + ΩDM + ΩB δρν δρDM
Free Streaming Scale
m⇤ = 8⇡ ⇤ (1.66g⇤)v2
MP
(92)
m1
⇡ m⇤ (93)
1
T1/2
= G0⌫(E,Z) |M0⌫ | |hm��i|2 (94)
Lfs
/ m�1/2
⌫ (95)
8
54
Neutrino Mass & Cosmology
Matter Power Spectrum
K. Abazajian ACFI neutrino mass workshop
Later Earlier
Neutrino Free Streaming
ΩM = Ων + ΩDM + ΩB δρν δρDM
Free Streaming Scale
m⇤ = 8⇡ ⇤ (1.66g⇤)v2
MP
(92)
m1
⇡ m⇤ (93)
1
T1/2
= G0⌫(E,Z) |M0⌫ | |hm��i|2 (94)
Lfs
/ m�1/2
⌫ (95)
8
δρν (power) suppressed for L < Lfs
55
Neutrino Mass & Cosmology
Matter Power Spectrum
K. Abazajian ACFI neutrino mass workshop
Later Earlier
Neutrino Free Streaming
ΩM = Ων + ΩDM + ΩB δρν δρDM
Free Streaming Scale
m⇤ = 8⇡ ⇤ (1.66g⇤)v2
MP
(92)
m1
⇡ m⇤ (93)
1
T1/2
= G0⌫(E,Z) |M0⌫ | |hm��i|2 (94)
Lfs
/ m�1/2
⌫ (95)
8
δρν (power) suppressed for L < Lfs
Suppression moves to smaller scales ! Larger k
Increase mν
56
Neutrino Mass & Cosmology
Matter Power Spectrum
K. Abazajian ACFI neutrino mass workshop
Neutrino Free Streaming
ΩM = Ων + ΩDM + ΩB δρν δρDM
Free Streaming Scale
m⇤ = 8⇡ ⇤ (1.66g⇤)v2
MP
(92)
m1
⇡ m⇤ (93)
1
T1/2
= G0⌫(E,Z) |M0⌫ | |hm��i|2 (94)
Lfs
/ m�1/2
⌫ (95)
8
δρν (power) suppressed for L < Lfs
Suppression moves to smaller scales ! Larger k
Increase mν
Later Earlier
Increase mν
Σ mv < 0.12 eV Palanque-Dalabrouille ‘15
57
St’d Mech: What Would a Null Result Imply ? Three active light neutrinos
Lightest neutrino mass (eV) !
Effe
ctiv
e D
BD
neu
trino
mas
s (e
V)
Inverted
Ton Scale
3H decay cur gen
Null result in NLDBD & non-zero mν from cosmology ! Conclusion depends on mlightest & hierarchy
Normal
3H decay next gen
Cosmo current
Current generation Current generation
58
St’d Mech: What Would a Null Result Imply ? Three active light neutrinos
Lightest neutrino mass (eV) !
Effe
ctiv
e D
BD
neu
trino
mas
s (e
V)
Inverted
Ton Scale
3H decay cur gen
Null result in NLDBD & non-zero mν from cosmology ! Conclusion depends on mlightest & hierarchy
Normal
Current generation Current generation
Cosmo current
3H decay next gen
P. Vogel
59
Lecture VIII Summary • Simplest type I see-saw mechanism with Majorana 3 NR + CPV
provides ingredients for baryogenesis via thermal leptogenesis
• “Standard leptogenesis” ! MN1 > 109 GeV
• Observation of 0νββ-decay consistent with “standard mechanism” would demonstrate existence of one key ingredient for thermal leptogenesis
• Discovery of TeV scale (and below) LNV (0νββ-decay + LHC…) would preclude high scale leptogenesis & point to alternate, low-scale scenarios (ARS lepto, EW baryo…)
• Precision cosmology (large scale structure, CMB) places tight constraints on Σmν for the three light active neutrinos, squeezing the viability of the IH region for mββ
• Challenge for theory: are there any well-motivated loopholes to cosmological constraints ?
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