Search for neutrinos from diffuse dark matter annihilation at Super-Kamiokande

Piotr MijakowskiWarsaw University / A.Soltan Institute For Nuclear Studies

DIFFUSE ANALYSIS

2

Moment. [GeV]cosreconstr.

M = 5.6 GeV

M = 5.6 GeV

EXAMPLE: illustration of 5.6 GeV WIMP annihilation signal in SK

DM signal shapeenhanced for illustration

DATASK1,2,3

ATM MC with oscillationsSK 2 flavor best fit

signal shown only in 2 samples

(out from 16)

signal is before FIT

» Search for diffuse DM annihilationsignal:

Monoenergetic E = M

Isotropic

assume 100% BR

€

+ → +

» Search for such a signal in Search for such a signal in atmospheric neutrino data of Super-atmospheric neutrino data of Super-Kamiokande-I, -II & –III Kamiokande-I, -II & –III livetime:livetime: FC/PC 2806 days, UPMU 3109 daysFC/PC 2806 days, UPMU 3109 days

» FIT: for each tested WIMP mass, find the best configuration of ATM MC + DM signal that would match DATA the best

» Simulate Simulate signalsignal & detector & detector responseresponse

‘golden channel’» Distinctive signatures:

» using all using all SKSK samples: samples: e-like + mu-like FC+PC+UPMU e-like + mu-like FC+PC+UPMU (wide energy range)(wide energy range)

» Conservative upper limit on WIMP total self-annihilation cross section <V>

» No allowed excess of DM-induced ’s for M in range 3GeV – 3 TeV

» FIT based on FIT based on EEvisvis & & coscos distr., distr.,

systematics included systematics included (120 sys. terms (120 sys. terms fitted)fitted)

» Focus on signal arising from Milky Way halo (diffuse flux)

Limit on <v>

FIT results

above is excluded

MW Halo Average (*)

JJ is is integrated intensity over all sky integrated intensity over all sky =2=2, ,

depends on DM halo density profile depends on DM halo density profile

Details on JJ calculation and motivation for this analysis:

(*) H.Yuksel et al., Phys. Rev. D76, 123506 (2007), arxiv: 0707.0196 [astro-ph]

€

dφΔΩdE

=σ A ⋅V

2JΔΩ

Rscρ sc2

4π ⋅mχ2

dN

dE

(*)(*)

ILLUSTRATIONS

5

Piotr MijakowskiInstytut Problemów Jądrowych, Warszawska Grupa

Neutrinowa

Piotr MijakowskiInstytut Problemów Jądrowych im. Andrzeja Sołtana,

Warszawska Grupa Neutrinowa

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Super-Kamiokande

• 50kton water, 22.5kton fiducial volume

• 12k inner PMTs /2k outer PMTs

detect light; possible reconstruction of energy and direction of neutrinos

• SK investigates atmopsheric/cosmic,

solar & accelerator • detect SN1987 ’s

• neutrino oscilation discovery (1998)

Water Cerenkov detector in Kamioka, Japan

• in operation since 1996

40m

40m

How neutrinos interact?

Charged Current

Neutral Current

Elastic Scattering

+ N->e+p+… + N->+n+…

+ e-->+e-

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SUPPLEMENTARY

10

DM signal illustrationDM signal illustration

cos

FC

PC

UPMU

Assuming Assuming ((ee)=)=((==((

for WIMP signal for WIMP signal P.Mijakowski

plot for atm. ’s

DM signal shapeenhanced for illustration

DATASK1,2,3

ATM MC with oscill.SK 2flavor best fit

M = 5.6 GeV

DM signal illustrationDM signal illustration M = 5.6 GeV

DM signal shapeenhanced for illustration

DATASK1,2,3

ATM MC with oscill.SK 2flavor best fit

Momentum [GeV].