Diffuse supernova neutrinos at underground laboratories Cecilia Lunardini Arizona State University And RIKEN BNL Research Center INT workshop “Long-Baseline Neutrino Physics and Astrophysics”
Dec 20, 2015
Diffuse supernova neutrinos at underground
laboratoriesCecilia Lunardini
Arizona State University And RIKEN BNL Research Center
INT workshop “Long-Baseline Neutrino Physics and Astrophysics”
• Motivations • Current status• The future:
– Detection potential– What can we learn?
• Extras: what else?
C. Lunardini, arXiv:1007.3252 (review)
Diffuse neutrinos from all SNe
• Sum over the whole universe:
Supernovae
S. Ando and K. Sato, New J.Phys.6:170,2004.
Motivations
Clip art from M. Vagins
Sooner and more• Faster progress
– Alternative to a galactic SN! • ~20 events/yr/Mt everyday physics!
• New science– What’s typical ?– New/rare SN types– Cosmological Sne
• Physics in the 10-100 MeV window?
Current status
The “ingredients”
Cosmological rate of
supernovae
Cosmological rate of
supernovae
Neutrino flux at production
+Propagation
effects: Oscillations
Redshift….
Neutrino flux at production
+Propagation
effects: Oscillations
Redshift….
Cosmology
Cosmology
Supernova rate
RSN(z) ~RSN(0) (1+z)β , z<1
normalization uncertainThis work: β=3.28, RSN(0) = 10-4 Mpc-3 yr-
1
Beacom & Hopkins, astro-ph/0601463
From Star Formation Rate
From SN data
Original spectra
• Models: – Lawrence Livermore– Thompson, Burrows, Pinto (Arizona)– Keil, Raffelt, Janka (Garching)
• 3 1053 ergs , equipartitioned between 6 species
Keil,, Raffelt,Janka, 2003 Astrophys. J. 590 971
x=μ, τ
Flavor oscillations• Self-interaction + MSW (H) + MSW (L)
– Spectral swap
• Depend on θ13 and hierarchy– Normal (inverted): ∆m2
31>0 (∆m231<0)
Jumping probability, PH
Duan, Fuller, Quian, PRD 74, 2006
C.L. & A. Y. Smirnov, JCAP 0306, 2003
• p= 0 – 0.32 , p = 0 – 0.68
Chakraborty et al., hep-ph/08053131
Higher energy tail
Higher energy tail
DSNnF spectrumExponential decay with E
LL
TBP KRJ
Neutrinos, p=0.32 Neutrinos, p=0
C.L., in preparation
Upper limits and backgrounds
Energy window
SuperKamiokande (Malek et al., PRL, 2003):
Red dashed: HomestakeSolid, grey: Kamioka
anti-e flux: predictions
C.L., Astropart.Phys.26:190-201,2006
The future: detection potential
Detectiontechnology
mass Reaction Energy window
Events/(5 yrs)
Water Cherenkov
0.4 Mt Anti-nue, inverse beta,(90% eff.)
19 – 40 MeV
27 - 227
Water + Gadolinium(GADZOOKS)
0.0225 Mt Anti-nue, inverse beta(90% eff.)
11 – 40 MeV
4 - 17
Liquid Argon 0.1 Mt nue + Ar, CC(100% eff.)
19 – 40 MeV
6 – 28
Liquid Scintillator (LENA)
50 kt Anti-nue, inverse beta(100% eff.)
11 – 40 MeV
O(10)
Water Energy window Background/signal ~ 5
-6(at Kamioka)
Fogli et al., JCAP 0504, 002, 2005
Background/signal ~ 5 -6
(at Kamioka)Fogli et al., JCAP 0504, 002,
2005
Bulk of events missed
Bulk of events missed
Large statistics: ~ 1-2 events/MeV/yr Large statistics: ~ 1-2 events/MeV/yr
GADZOOKS Energy window Background/signal<1
Invisible muons reduced to 1/5
Beacom & Vagins, PRL93, 2004
Background/signal<1Invisible muons reduced
to 1/5Beacom & Vagins, PRL93, 2004
Larger energy window:
Bulk of events captured!
Larger energy window:
Bulk of events captured!
Modest statistics… Scaling to Mt??
Modest statistics… Scaling to Mt??
LAr Energy window
Background/signal ~ 0.2-0.3
Background/signal ~ 0.2-0.3
Bulk of events may be captured!
Bulk of events may be captured!
Statistics modest: ~0.2
events/yr/MeVScaling?
Statistics modest: ~0.2
events/yr/MeVScaling?
New!
C.L., in preparation
What can we learn?
Water+Gd: effective spectrum
Normalized to 150 events, b=3.28
C.L., Phys.Rev.D75:073022,2007
A step beyond SN1987A!
• Test SN codes of spectra formation, some oscillation effects, etc.
• 0.1 Mt yr :– Tests part of
parameter space– May not reach
SN1987A region
0.1 Mt yr
Yuksel, Ando and Beacom, Phys.Rev.C74:015803,2006
Chance to test
r ~ 0.6 – 0.9
Normalized to 150 events
C.L., Phys.Rev.D75:073022,2007
New SN types: failed SNe• M > 40 Msun, 9-22% of all collapses
• Direct BH-forming collapse (no explosion):– Higher energies: E0 ~ 20 – 24 MeV
• For all flavors• Due to rapid contraction of protoneutron star
before BH formation
– Electron flavors especially luminous• (e- and e+ captures)
Liebendörfer et al., ApJS, 150, 263, K. Sumiyoshi et al., PRL97, 091101 (2006), T. Fischer et al., (2008), 0809.5129, K. Nakazato et al., PRD78, 083014 (2008)
– Progenitor: M=40 Msun, from Woosley & Weaver, 1995– “stiffer” eq. of state (EoS) more energetic neutrinos
Shen et al. (S) EoS
Anti-nue
nux
nue
BH
NS
K. Nakazato et al., PRD78, 083014 (2008)
Number of events: water..• Best case scenario: 22% failed, S EoS
Total
Normal
Failed
C.L., arXiv:0901.0568, Phys. Rev. Lett., 2009, J. G. Keehn and C.L., in preparation
LAr• Bulk of events from failed SNe captured• Failed SN at least a 10% effect in energy window
J. Keehn & C.L., in preparation
Failed
Normal
Total
Reducing uncertainties
• Precise SN rates coming soon from astronomy
• Neutrino uncertainties more serious– SN modeling?– Galactic SN?
http://snap.lbl.gov/ http://www.jwst.nasa.gov/,
C.L., Astropart.Phys.26:190-201,2006
Extras
What else is there?
Neutrinos from solar flares?
• LSD: 27 flares examined in 3 years
• Mt-size advocated for detectionR
elic SN, 1 year
Flare, best
Flare,conservativeErofeeva et al., 1988; Bahcall PRL 1988Kocharov et al., 1990, Fargion et al., 2008
Aglietta et al., 1990
Miro
shni
chen
ko e
t al
., S
pace
Sci
ence
Rev
iew
s 91
: 61
5–71
5, 2
000
Solar antineutrinos
• Spin-flavor oscillations– νe anti-νe
Rashba & Raffelt, Phys.Atom.Nucl.73:609-613,2010
Neutrinos from relic decay/annihilation
• χ ν + anti-ν• χ+ χ ν + anti-ν
Gamma rays
Yuksel & Kistler, PRD, 2007
Palomares Ruiz & Pascoli, Phys.Rev.D77, 2008Palomares Ruiz, Phys.Lett.B ,2008
MeV Dark Matter absorption
Kile and Soni, Phys.Rev.D80:115017,2009
Summary• DSNnF may be seen with few years running!
– 100 kt LAr : O(10) events– 0.4 Mt water : O(102) events
• New science:– Typical neutrino emission– Sensitive to failed Sne– Other physics in energy window?
• To advance further:– Resolve parameter degeneracies (theory)– reduce background at low E