Johannes Gutenberg-Universität Mainz Institut für Kernphysik Probing the Dark Sector by Electromagnetic Interactions T. Beranek 1 , A. Denig 1 , M. Vanderhaeghen 1 1 Institut für Kernphysik, Johannes Gutenberg-Universität Mainz, Deutschland EMG Annual Retreat, Bingen, 27.09. - 29.09.2010 Tobias Beranek Probing the Dark Sector by Electromagnetic Interactions
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Probing the Dark Sector by Electromagnetic Interactions · Probing the Dark Sector by Electromagnetic Interactions T. Beranek1, A. Denig1, M. Vanderhaeghen1 1Institut für Kernphysik,
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Johannes Gutenberg-Universität MainzInstitut für Kernphysik
Probing the Dark Sector byElectromagnetic Interactions
T. Beranek1, A. Denig1, M. Vanderhaeghen1
1Institut für Kernphysik, Johannes Gutenberg-Universität Mainz, Deutschland
EMG Annual Retreat,Bingen, 27.09. - 29.09.2010
Tobias Beranek Probing the Dark Sector by Electromagnetic Interactions
Johannes Gutenberg-Universität MainzInstitut für Kernphysik
Implications from Indirect Dark Matter Detection
χ
χ
SM
SM PAMELASharp upturn in positron fraction from10− 100 GeV;in contraction to expectation frominteractions of high-energy cosmic rayswith ISM
Possible explanation DM→ e+e−, butunnaturally large cross section andsuppressed p production required⇒ Contradiction to WIMP DM
DM charged under new gaugesymmetry automatically has correctthermal relic abundance like WIMP DMand can explain observations⇒ new massive gauge boson A′ atmass scale 50 MeV to 1 GeV!
O. Adriani et al. [PAMELA Collaboration], Nature 458 (2009) 607 [arXiv:0810.4995 [astro-ph]]N. Arkani-Hamed, D. P. Finkbeiner, T. R. Slatyer and N. Weiner, Phys. Rev. D 79 (2009) 015014
Tobias Beranek Probing the Dark Sector by Electromagnetic Interactions
Johannes Gutenberg-Universität MainzInstitut für Kernphysik
Motivation for New Physics at the GeV ScaleThe GeV-scale of the A′ mass can be motivated from
SUSYLow-energy SUSY allows to determine the A′ mass from same physicsgenerating W± and Z 0 massesElectroweak symmetry breaking generates a mass term for the A′, thus
mA′ ∼ MeV − GeV
ObservationsCalculations for DM annihilationswith O(GeV) A′ andSommerfeld enhancementreconcile PAMELA data
p production kinematicallysuppressed
0.01
0.1
1
10 100
φ e+ /
(φe+
+ φ
e- )
Energy (GeV)
e+e- Channel
mχ = 850 GeV, BF = 450
mχ = 300 GeV, BF = 64
mχ = 100 GeV, BF = 8.1
Background
PAMELA Data
I. Cholis, G. Dobler, D. P. Finkbeiner, L. Goodenough and N. Weiner, Phys. Rev. D 80 (2009) 123518R. Essig, J. Kaplan, P. Schuster and N. Toro, arXiv:1004.0691 [hep-ph].
Tobias Beranek Probing the Dark Sector by Electromagnetic Interactions
Johannes Gutenberg-Universität MainzInstitut für Kernphysik
Motivation for New Physics at the GeV Scale
l
l′
χ
χ
γ A′
Standard Model ExtensionsInteraction with SM particles:L = g′ A′µψγµψ
Kinetic mixing between two U(1)gauge symmetry force carriers, e.gγ and A′, i.e. Lmix = ε
2 FµνY F ′µν withnaturally ε . 10−1 − 10−9 is a possibleSM extension
Consequence: A′ opens window to ahidden sector, that can be studied withfixed target experiment at moderateenergies (Bjorken et al.) and probe e.g.supersymmetry at relatively lowenergies
B. Holdom, Phys. Lett. B 166 (1986) 196.J. D. Bjorken, R. Essig, P. Schuster and N. Toro, Phys. Rev. D 80, 075018 (2009)
Tobias Beranek Probing the Dark Sector by Electromagnetic Interactions
Johannes Gutenberg-Universität MainzInstitut für Kernphysik
Motivation for New Physics at the GeV Scale
l
l′A′ǫ
Standard Model ExtensionsInteraction with SM particles:L = ε e A′µψγµψ
Kinetic mixing between two U(1)gauge symmetry force carriers, e.gγ and A′, i.e. Lmix = ε
2 FµνY F ′µν withnaturally ε . 10−1 − 10−9 is a possibleSM extension
Consequence: A′ opens window to ahidden sector, that can be studied withfixed target experiment at moderateenergies (Bjorken et al.) and probe e.g.supersymmetry at relatively lowenergies
B. Holdom, Phys. Lett. B 166 (1986) 196.J. D. Bjorken, R. Essig, P. Schuster and N. Toro, Phys. Rev. D 80, 075018 (2009)
Tobias Beranek Probing the Dark Sector by Electromagnetic Interactions
Johannes Gutenberg-Universität MainzInstitut für Kernphysik
A New Dark Gauge Bosonχ
χ
A′
A′
l+
l−
l+
l−
Production at Accelerators(a) + (b): Production at e+e− colliders:⇒ powerful tool at larger masses andε, but limited by luminosity andbackground(c): Production from fixed nucleontarget:⇒ much larger luminosities can beachieved, existing experiments provideadequate setups for search
e−
e+
X
X
A′∗
(a)
e−
e+
γ
A′(b)
e− e−
γ∗
A′
N N(c)
Tobias Beranek Probing the Dark Sector by Electromagnetic Interactions