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

supernovaeNeutrino flux at

production +

Propagation effects:

OscillationsRedshift

….

Cosmology

Supernova rateRSN(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

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

Bulk of events missed

Large statistics: ~ 1-2 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 ~ 0.2-0.3

Bulk of events may be captured!

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 b

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

nueBH

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 detectionRelic 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.,

Spa

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cien

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91: 6

15–7

15, 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