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DirectDetec(onofDarkPhoton
HaipengAn(Caltech)
UCLADarkMa;er2016
Whatisdarkphoton?
• Lagrangian
•
•
L = �14V µ⌫Vµ⌫ +
1
2m2V V
µVµ �1
2V µ⌫Fµ⌫
mV < 1 MeVV ! 3�
The dark photon can easily be cosmologically stable, and play the roll of dark matter. mV > 1 MeV
V ! e+e�
�V /2↵4m9V
m8e
The dark photon plays the roll of the mediator of the force of dark matter self interaction.
X
Sourcesofdarkphoton
• Natural sources – The Sun – Dark matter surround us if it composes the dark matter
• Man-made sources – From laser beam (LSW) – From antennas (CROWS) – Various colliders (for heavy dark photon)
• Signal rate
– Total absorption rate; – Solar flux; – Branching ratio to desired signals.
Branchingra(otothedesiredsignal.
Totalabsorp(onrate
FluxfromtheSun
Solardarkphoton
Sun Earth
Darkphoton,V
Solardarkphoton
• Resonant production conditions – Transverse mode: – Longitudinal mode:
• Inside the Sun
Solardarkphoton
mV = !p! = !p
!p : plasma frequency
! : energy of dark photon
mV : mass of dark photon
1 eV < !p < 300 eV
HA,M.Pospelov,J.Pradler1302.3884&PLB
�L dominates if mV . 10 eV�T dominates if 10 eV . mV . 300 eV
Solardarkphoton
! ⇡ !p , 1 eV < !p < 300 eV
The detector should be able to detect ~ 100 eV energy deposition.
HA,M.Pospelov,J.Pradler1309.6599
300eV
Solardarkphoton
PMT PMT PMT PMT
PMT PMT PMT PMT
E
E
V
X A(*)
Xenonliquid
Xenongas
e-
Xenonatom
photons
• We are looking at electron recoils.
• Up to now only XENON10 collaboration has published the result in this energy region.
Solardarkphoton
• XENON10 S2 only analysis
•
Numberofelectrons
300eV~25electrons
Photo-ionization dominates.
XENON101104.3088
XENON10constraint
HA,M.Pospelov,J.Pradler1304.3461&PRL
ConstraintfromB8neutrinofromthecenteroftheSun.
HA,M.Pospelov,J.Pradler1302.3884&PLB
• Coherent oscillation
• Generated during inflation – Transverse modes cannot be generated due to conformal
invariance – Longitudinal mode, OK
Darkphotondarkma;er
1
2m2V V
2
Graham,Mardon,Rajendran1504.02102
Darkphotondarkma;er
PMT PMT PMT PMT
PMT PMT PMT PMT
E
E
V
X A(*)
Xenonliquid
Xenongas
e-
Xenonatom
photons
• Nonrelativistic
• Can be detected by XENON detector if .
• Use S2 only analysis
• Use S1 + S2 analysis
v ⇠ 10�3 ! ⇡ mV
mV > 12 eV
if mV < 1 keV
if mV > 1 keV
S1photons
Darkphotondarkma;er
HA,M.Pospelov,J.Pradler,A.Ritz1412.8378HA,M.Pospelov,J.Pradler,A.Ritz,K.Ni1510.04530
Heavydarkphotonasadarkforce
• How to know the dark photon is the mediator of dark matter self interaction?
• If the self interaction is strong enough, the dark matter can form a bound state.
• We propose to use the high luminosity B factories to search for dark bound states.
HeavydarkphotonasadarkforceHA,B.Echenard,M.Pospelov,Y.Zhang1510.05020
Hg- 2Le
E744
E141
Orsay
U70
CHARM
Hg - 2Lm Dark photonûBABARNA48 ê 2
hD and UDûBABAR
future B factory
nobound
states
Hcurrent limit, aD=0.25L
Hcurrent limit, aD=0.5LHfuture limit, aD=0.25L
Hfuture limit, aD=0.5L
0.005 0.01 0.02 0.05 0.1 0.2 0.5 1. 210-6
10-5
10-4
0.001
0.01
mV HGeVL
k
mD = 3.5 GeV
Summaryandoutlook
• mV < 1 MeV – Dark matter detectors (sensitive to electron recoils) can be used
to detect both solar dark photon and dark photon dark matter. – To detect sub-keV energy dark photon, we need to further
understand the S2 background of the detectors. – In principle, all the detectors designed for detecting axion dark
matter can be used to detect dark photon dark matter • Microwave cavity (ADMX PRL 105,171801) • LC circuit (proposed by Chaudhuri, Graham, Irwin 1411.7382) • NMR • …
Summaryandoutlook
• mV > 1 MeV – If the dark matter can form bound state, we can use high
luminosity colliders to study the property of dark matter bound state. • Belle II • SeaQuest • SHiP
Backup
Solardarkphoton
• Scalingwiththemass
– Produc(onrate
– Absorp(onrate
mV ⌧ !p
�T / (mV /!p)4 , �L / (mV /!p)2 ,
m2V ⌧ |(✏r � 1)!2|
�T / [m2V /|(✏r � 1)!2|]2 , �L / m2V /|(✏r � 1)!2| ,