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10 18 eV Neutrinos associated with UHECR (>10 19 eV) sources Zhuo Li ( 黎黎 ) Peking University, Beijing Collaborators: Eli Waxman & Liming Song Li & Waxman, arXiv:0711.4969

10 18 eV Neutrinos associated with UHECR (>10 19 eV) sources Zhuo Li ( 黎卓 ) Peking University, Beijing Collaborators: Eli Waxman & Liming Song Li & Waxman,

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Page 1: 10 18 eV Neutrinos associated with UHECR (>10 19 eV) sources Zhuo Li ( 黎卓 ) Peking University, Beijing Collaborators: Eli Waxman & Liming Song Li & Waxman,

1018eV Neutrinos associated with UHECR (>1019eV) sources

Zhuo Li (黎卓 )Peking University, Beijing

Collaborators: Eli Waxman & Liming Song

Li & Waxman, arXiv:0711.4969

Page 2: 10 18 eV Neutrinos associated with UHECR (>10 19 eV) sources Zhuo Li ( 黎卓 ) Peking University, Beijing Collaborators: Eli Waxman & Liming Song Li & Waxman,

Why EeV neutrino

• To directly identify CR sources

• Neutrino– Pointing to the source– Avoiding absorption

• 1018eV– Primary >1019eV

Page 3: 10 18 eV Neutrinos associated with UHECR (>10 19 eV) sources Zhuo Li ( 黎卓 ) Peking University, Beijing Collaborators: Eli Waxman & Liming Song Li & Waxman,

HE Neutrinos from CR accelerators

-production in accelerators:– acc. p’s; acc. e’s : synchrotron/IC photons

• If all p energy converted to (in the source)

• Waxman-Bahcall Bound for sources optically thin to p:

GZK

0/

2

1

2

1

Hc

j

j

p

Waxman & Bahcall 1999

eeNpp ;)(

sr scm

GeV10

d

d2

82

j

Page 4: 10 18 eV Neutrinos associated with UHECR (>10 19 eV) sources Zhuo Li ( 黎卓 ) Peking University, Beijing Collaborators: Eli Waxman & Liming Song Li & Waxman,

UHECR source: acceleration

Page 5: 10 18 eV Neutrinos associated with UHECR (>10 19 eV) sources Zhuo Li ( 黎卓 ) Peking University, Beijing Collaborators: Eli Waxman & Liming Song Li & Waxman,

GRB HE ’s: p interaction

→(~10-8s)

→ee (~10-6s)

-resonance: 1 MeV 1014eV.

pp=0.2GeV=0.2GeV2222

pp

Page 6: 10 18 eV Neutrinos associated with UHECR (>10 19 eV) sources Zhuo Li ( 黎卓 ) Peking University, Beijing Collaborators: Eli Waxman & Liming Song Li & Waxman,

Spectral cutoff: EM cooling

100TeV ~1PeV

f

Neutrino energy

n• For >10PeV protons, the

fraction of total energy loss

• Suppressed by pi+/mu+ EM energy loss

life, tcool1/

[Kashiti & Waxman 2005;Rachen & Meszaros 1998]

[Waxman & Bahcall 1997]

No UHE neutrinos, how to identify UHECR sources?

Page 7: 10 18 eV Neutrinos associated with UHECR (>10 19 eV) sources Zhuo Li ( 黎卓 ) Peking University, Beijing Collaborators: Eli Waxman & Liming Song Li & Waxman,

EeV neutrinos: 0-induced

100TeV 1PeV

f

WB bound: f

Prompt~10sec

No cooling suppression;3% WB bound

1EeV

Page 8: 10 18 eV Neutrinos associated with UHECR (>10 19 eV) sources Zhuo Li ( 黎卓 ) Peking University, Beijing Collaborators: Eli Waxman & Liming Song Li & Waxman,

HE ’s from neutral 0 production

• Processes

e

e

e

pp

e

np

cmb

0

0

[Li & Waxman 2007b]

EM cooling suppression

no cooling suppression

eV1

10

)(

)( 19

cmb

22

zzT

cm

CMB

Page 9: 10 18 eV Neutrinos associated with UHECR (>10 19 eV) sources Zhuo Li ( 黎卓 ) Peking University, Beijing Collaborators: Eli Waxman & Liming Song Li & Waxman,

• Q1: suppressed by e+- production?

• Q2: deflected by IGM field (hence delayed)?

[Li & Waxman 2007b]

eecmb

cross section -1, similar above threshold

n+2

CMB peak

e+- thr. +- thr.=1019-20eV, /e=(3-10)%

ms )cm10/()G10/(1

/

degree )G10/(10

)s102( /

2729

2

98

6

B

ct

B

tcmeBt

B

Page 10: 10 18 eV Neutrinos associated with UHECR (>10 19 eV) sources Zhuo Li ( 黎卓 ) Peking University, Beijing Collaborators: Eli Waxman & Liming Song Li & Waxman,

Q3: HE ’s escape from source?

• Attenuated by e+- production in source – low energy break

– KN suppression of cross section

• Strong synchrotron absorption below keV

• Conclusion: >10PeV photons don’t suffer attenuation

[Li & Waxman 2007b]

[Li & Waxman 2007a]

[Li & Song 2004]

dn/d

~1keV ~1MeV

Page 11: 10 18 eV Neutrinos associated with UHECR (>10 19 eV) sources Zhuo Li ( 黎卓 ) Peking University, Beijing Collaborators: Eli Waxman & Liming Song Li & Waxman,

EeV neutrinos: a new channel

0.03

100TeV 1PeV

0.2

WB bound

1EeV

[Li & Waxman 2007b]

1

20/km2yr1km2 experiment

association (time/direction): directly identify sources

Page 12: 10 18 eV Neutrinos associated with UHECR (>10 19 eV) sources Zhuo Li ( 黎卓 ) Peking University, Beijing Collaborators: Eli Waxman & Liming Song Li & Waxman,

• Coherence radio Cerenkov:

• ANITA (balloon)• ARIANNA (array)

– ~1/yr expected

[Barwick 2007]