Transcript "Diffuse supernova neutrinos at underground laboratories"

Diffuse supernova neutrinos
at underground laboratories
Cecilia 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
Neutrino flux at
production
+
Propagation
effects:
Oscillations
Redshift
….
Cosmology
From Star Formation Rate
From SN data
Supernova rate
RSN(z) ~RSN(0) (1+z)β , z<1
normalization uncertain
This work: β=3.28, RSN(0) = 10-4 Mpc-3 yr-1
Beacom & Hopkins, astro-ph/0601463
Original spectra
• Models:
– Lawrence Livermore
– Thompson, Burrows, Pinto (Arizona)
– Keil, Raffelt, Janka (Garching)
Keil,, Raffelt,Janka, 2003
Astrophys. J. 590 971
x=μ, τ
• 3 1053 ergs , equipartitioned between 6 species
Flavor oscillations
• Self-interaction + MSW (H) + MSW (L)
– Spectral swap
Duan, Fuller, Quian, PRD 74, 2006
• Depend on θ13 and hierarchy
– Normal (inverted): ∆m231>0 (∆m231<0)
Jumping probability, PH
C.L. & A. Y. Smirnov,
JCAP 0306, 2003
Higher
energy tail
• p= 0 – 0.32 ,
p = 0 – 0.68
Chakraborty et al., hep-ph/08053131
DSNnF spectrum
Exponential decay with E
LL
TBP
KRJ
C.L., in preparation
Upper limits and backgrounds
SuperKamiokande (Malek et al., PRL, 2003):
Energy window
Red dashed: Homestake
Solid, grey: Kamioka
anti-e flux: predictions
C.L., Astropart.Phys.26:190-201,2006
The future: detection
potential
Detection
technology
mass
Reaction
Energy
window
Events/(
5 yrs)
Water
Cherenkov
0.4 Mt
Anti-nue,
19 – 40 MeV
inverse beta,
(90% eff.)
27 - 227
Water +
0.0225 Mt
Gadolinium
(GADZOOKS)
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
Bulk of
events
missed
Large statistics: ~ 12 events/MeV/yr
GADZOOKS
Energy window
Background/signal<1
Invisible muons reduced to
1/5
Beacom & Vagins, PRL93, 2004
Larger energy
window:
Bulk of events
captured!
Modest statistics…
Scaling to Mt??
LAr
Energy window
Background/signal ~ 0.20.3
Bulk of events may be
captured!
Statistics modest:
~0.2 events/yr/MeV
Scaling?
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
• 0.1 Mt yr :
– Tests part of
parameter space
– May not reach
SN1987A region
Yuksel, Ando and Beacom, Phys.Rev.C74:015803,2006
Chance to test b
Normalized to 150 events
r ~ 0.6 – 0.9
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)
Shen et al. (S) EoS
BH
NS
K. Nakazato et al.,
PRD78, 083014 (2008)
– Progenitor: M=40 Msun, from Woosley & Weaver, 1995
– “stiffer” eq. of state (EoS)  more energetic neutrinos
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
Total
Normal
Failed
J. Keehn & C.L., in preparation
Reducing uncertainties
• Precise SN rates coming soon from
astronomy
http://snap.lbl.gov/
http://www.jwst.nasa.gov/,
• Neutrino uncertainties more serious
– SN modeling?
– Galactic SN?
C.L., Astropart.Phys.26:190-201,2006
Extras
What else is there?
Miroshnichenko et al., Space Science Reviews 91: 615–715, 2000
Neutrinos from solar flares?
• LSD: 27 flares
examined in 3 years
Aglietta et al., 1990
Flare, best
Flare,conservative
• Mt-size advocated
for detection
Erofeeva et al., 1988; Bahcall PRL 1988
Kocharov et al., 1990, Fargion et al.,
2008
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
Palomares Ruiz & Pascoli, Phys.Rev.D77, 2008
Palomares Ruiz, Phys.Lett.B ,2008
Yuksel & Kistler, PRD, 2007
Gamma rays
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