what can we really learn from positron flux 'anomalies'? boaz katz, kfir blum, eli waxman...
TRANSCRIPT
What can we really learn from positron flux 'Anomalies?'
Boaz Katz, Kfir Blum, Eli Waxman
arXiv:0907.1686
…Our results clearly show an increase in the positron abundance at high energy that cannot be understood by standard models describing
the secondary production of cosmic-rays .
PAMELA
• e+ ~ pbar / radiative losses
• pbar understood
• Measure e+ measure losses
• 10Be agrees secondary!
• e+/pbar theoretically clean
Plan:
• e+ `anomaly’ ???
• Propagation models fit grammage.
e+ lose energy radiatively( -ordinarily )steep spectrum, loss suppresses flux.
Ignore energy loss upper bound on flux.
e+ produced in pp and spallation interactions
– similar to , B, Sc, Li,…
e+ ~ pbar / radiative losses
Pbar understood: Stable secondaries, no loss
In general
…If*:
• Propagation only depends on magnetic rigidity
• Rigidity fixed on propagation
• Homogenous composition*Also used the fact that spallation secondary inherits rigidity of primary
Pbar understood: Stable secondaries, with loss
nP,out
n’A,out nA,in
nP,in
n’’A,out
nP,out
nA,in
nP,in
nA,out
Equivalently:
Homogenous composition :
Qeff works just the same!
Why does it work so well??
Summary & Outlook
• Interpreting e+ data
e+ ~ pbar / radiative losses; pbar understood
Measure e+ measure losses
• `Anomaly’ ? Doesn’t seem so right now10Be agrees secondary!
No tension with model independent estimates
Wait for further data release. PAMELA reach Ee+< 270 GeV
• e+/pbar theoretically clean
define model independent tests for exotics
• Propagation models fit grammage
what does it mean to be conservative?
?