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
8
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].