Resonant absorption of dark matter in molecules Ken Van Tilburg - PowerPoint PPT Presentation

Resonant absorption of dark matter in molecules Ken Van Tilburg (NYU & IAS) arXiv:1709.05354, Phys. Rev. X 8 , 041001 with Asimina Arvanitaki (Perimeter), Savas Dimopoulos (Stanford) Karl Berggren (MIT), Ilya Charaev (MIT), Jeff Chiles (NIST), Marco Colangelo (MIT), Andrew Dane (MIT), SaeWoo Nam (NIST), Varun Verma (NIST) in progress with Masha Baryakhtar (NYU), Junwu Huang (Perimeter), Robert Lasenby (Stanford) DOE QuantiSED grant, DE-SC0019129 Light Dark Matter Workshop, KICP/Fermilab, 2019/06/06

Outline (1) Dark matter fields can resonantly excite a molecular system bosonic DM couplings | two-level system dynamics | molecular levels (2) Experimental setup configurations | photon detection | backgrounds | discrimination (3) Dark matter sensitivity 0 . 2 eV < m < 20 eV hidden vectors | moduli | axions

Outline (1) Dark matter fields can resonantly excite a molecular system bosonic DM couplings | two-level system dynamics | molecular levels (2) Experimental setup configurations | photon detection | backgrounds | discrimination (3) Dark matter sensitivity 0 . 2 eV < m < 20 eV hidden vectors | moduli | axions Why is a molecular gas a good dark matter detector? energy resolution: ∆ ω / ω ⌧ 10 − 6 signal rate control variables: P, T, E, B discrimination calculable power selection rules backgrounds ∆ θ / θ . 10 − 6 directional focusing:

Outline (1) Dark matter fields can resonantly excite a molecular system bosonic DM couplings | two-level system dynamics | molecular levels (2) Experimental setup configurations | photon detection | backgrounds | discrimination (3) Dark matter sensitivity 0 . 2 eV < m < 20 eV hidden vectors | moduli | axions Why is a molecular gas a good dark matter detector? energy resolution: ∆ ω / ω ⌧ 10 − 6 signal rate control variables: P, T, E, B discrimination calculable power selection rules backgrounds ∆ θ / θ . 10 − 6 directional focusing:

Bosonic dark matter couplings EFT of DM bosons coupled to electrons, quarks, photons, gluons inflationary production spin-1 kinetic mixing B-L charge µ J µ ✏ A 0 µ J µ gA 0 EM B � L misalignment mechanism spin-0 parity-even parity-odd ( ∂ µ a )¯ e γ µ γ 5 e φ ¯ ee ( ∂ µ a )¯ q γ µ γ 5 q φ ¯ qq φ F 2 aF ˜ F φ G 2 aG ˜ G

DM-induced transitions

Resonant excitation of a two-level system | 1 i γ 0 ω 0 | 0 i h 1 | δ H | 0 i ⇠ Ω cos( ω t ) Ω ω

Resonant excitation of a two-level system | 1 i k = mv k = m γ 0 ω 0 ω = m DM photon | 0 i h 1 | δ H | 0 i ⇠ Ω cos( ω t ) Ω ω

Resonant excitation of a two-level system | 1 i k = mv k = m γ 0 ω 0 ω = m DM photon | 0 i h 1 | δ H | 0 i ⇠ Ω cos( ω t ) Ω ω Γ abs = nV | Ω | 2 | Ω | 2 1 γ = γ rad + 2 γ col + ∆ ω ∆ ω nV 2 γ col γ rad 1 + 4( ω 0 − ω ) 2 π γ X γ 2 γ rad ' ¯ r γ 0 + # molecules γ i } } i lineshape γ col = n σ col v mol on-resonance absorption rate per molecule ∆ ω Doppler negligible

Resonant excitation of a two-level system | 1 i k = mv k = m γ 0 ω 0 ω = m DM photon | 0 i 2 Ω e i ( ω 0 � ω ) t � 1 0 δ Hdt 0 | 0 0 i ' | 0 0 i � i R t | Ψ ( t ) 0 i = e � i h 1 | δ H | 0 i ⇠ Ω cos( ω t ) | 1 0 i Ω Ω ω i ( ω 0 � ω ) ω ω 0 Γ abs = nV | Ω | 2 | Ω | 2 1 γ = γ rad + 2 γ col + ∆ ω ∆ ω nV 2 γ col γ rad 1 + 4( ω 0 − ω ) 2 π γ X γ 2 γ rad ' ¯ r γ 0 + # molecules γ i } } i lineshape γ col = n σ col v mol on-resonance absorption rate per molecule ∆ ω Doppler negligible

Molecular levels and transitions diatomic molecule atom solid ⇣ m e ⌘ ω rot ∼ α 2 m e ω el ∼ α 2 m e M DM ⌘ 1 / 2 ⇣ m e ω vib ∼ α 2 m e M discretuum of transition energies = multimode resonator

DM absorption rate ��� � = � 〉 → � = � 〉 � hidden photon DM � = � → � � = � → � �� � �� � � = � → � �� � �� � ✏ = 10 − 12 �� - � �� - � � � � V = 300 cm 3 �� - � Γ ��� [ �� ] T = 100 K �� - � P = 5 bar �� - � �� - � �� - � ����� ����� ����� ����� ω [ �� ]

DM absorption rate ��� � = � 〉 → � = � 〉 ��� � = � 〉 → � = � 〉 � � hidden photon DM � = � → � � = � → � � = � → � � = � → � �� � �� � �� � �� � � = � → � � = � → � �� � �� � �� � �� � ✏ = 10 − 12 �� - � �� - � �� - � �� - � � � � � � � V = 300 cm 3 �� - � �� - � Γ ��� [ �� ] Γ ��� [ �� ] T = 100 K �� - � �� - � P = 5 bar P = 0 . 05 bar �� - � �� - � �� - � �� - � �� - � �� - � ����� ����� ����� ����� ����� ����� ����� ����� ω [ �� ] ω [ �� ]

Outline (1) Dark matter fields can resonantly excite a molecular system bosonic DM couplings | two-level system dynamics | molecular levels (2) Experimental setup configurations | photon detection | backgrounds | discrimination (3) Dark matter sensitivity 0 . 2 eV < m < 20 eV hidden vectors | moduli | axions Why is a molecular gas a good dark matter detector? energy resolution: ∆ ω / ω ⌧ 10 − 6 signal rate control variables: P, T, E, B discrimination calculable power selection rules backgrounds ∆ θ / θ . 10 − 6 directional focusing:

Bulk configuration Phase I V = (0 . 3 m) 3 T = 300 K DCR = 1 Hz Phase II V = (2 m) 3 T = 100 K DCR = 10 − 3 Hz

Bulk configuration photodetector molecules Phase I V = (0 . 3 m) 3 T = 300 K DCR = 1 Hz Phase II V = (2 m) 3 T = 100 K DCR = 10 − 3 Hz absorption event fluorescence photon reflective coating

Cooperative radiation 2 coherence length: λ coh = mv 0 − ( v − v lab ) 2  � 2 π f ( v ) ∝ exp typical deBroglie wavelength: λ dB ∼ v 2 mv lab 0 λ γ = 2 π photon wavelength: m λ γ λ coh | 0 i + ε e − i [ mt + ϕ ( x )] | 1 i

Cooperative radiation 2 coherence length: λ coh = mv 0 − ( v − v lab ) 2  � 2 π f ( v ) ∝ exp typical deBroglie wavelength: λ dB ∼ v 2 mv lab 0 λ γ = 2 π photon wavelength: m λ γ λ coh | 0 i + ε e − i [ mt + ϕ ( x )] | 1 i

Cooperative radiation 2 coherence length: λ coh = mv 0 − ( v − v lab ) 2  � 2 π f ( v ) ∝ exp typical deBroglie wavelength: λ dB ∼ v 2 mv lab 0 λ γ = 2 π photon wavelength: m λ γ λ coh | 0 i + ε e − i [ mt + ϕ ( x )] | 1 i

Cooperative radiation 2 coherence length: λ coh = mv 0 − ( v − v lab ) 2  � 2 π f ( v ) ∝ exp typical deBroglie wavelength: λ dB ∼ v 2 mv lab 0 λ γ = 2 π photon wavelength: m λ γ λ coh | 0 i + ε e − i [ mt + ϕ ( x )] | 1 i r ' 1 + 8 π n ¯ m 4 R z ◆ 3 ✓ n ⇡ 1 + 5 ⇥ 10 6 ✓ 1 eV ◆ mR z m n 0

Stack configuration Phase I A = π (0 . 3 m) 3 D = 1 mm DCR = 10 − 5 Hz Phase II A = π (2 m) 3 D = 100 mm DCR = 10 − 7 Hz λ γ T = 100 K

Stack configuration Phase I A = π (0 . 3 m) 3 D = 1 mm DCR = 10 − 5 Hz Phase II A = π (2 m) 3 D = 100 mm DCR = 10 − 7 Hz λ γ molecules T = 100 K transparent dielectric

Stack configuration photodetector Phase I A = π (0 . 3 m) 3 D = 1 mm DCR = 10 − 5 Hz lens Phase II cooperatively A = π (2 m) 3 emitted D = 100 mm photon DCR = 10 − 7 Hz λ γ molecules T = 100 K transparent dielectric

Stack configuration photodetector η coh ' (¯ r � 1) γ 0 Phase I r γ 0 + 2 γ col ¯ A = π (0 . 3 m) 3 D = 1 mm DCR = 10 − 5 Hz lens Phase II cooperatively A = π (2 m) 3 emitted D = 100 mm photon DCR = 10 − 7 Hz λ γ molecules T = 100 K transparent dielectric

Absorption + Cooperative emission ��� � = � 〉 → � = � 〉 @ � = � ���� � = ��� � �� �� � hidden photon DM � = � → � � = � → � �� � �� � � = � → � �� � �� � ✏ = 10 − 12 �� - � �� - � � � � �� - � Γ [ �� ] �� - � Γ ��� �� - � � = � ← � �� - � � Γ ��� V = π (30 cm) 2 (1 mm) �� - � ����� ����� ����� ����� ω [ �� ]

Key considerations frequency coverage radiative efficiency ���� fluorescence collisional broadening Bulk: before ������ ���� quenching molecular species or isotope shift ������ ���� Zeeman tuning cooperative emission (magnetic field) ������ ���� Stack: before decoherence Stark tuning (electric field) ������

Backgrounds dark count rate (DCR): high-reflectivity coatings cryogenic photodetectors: SNSPD, MKID, TES nV e − ω 0 thermal occupation / BBR: T ⌧ 1 natural/cosmogenic radioactivity: high-purity shield + components Γ RD ∼ 10 − 2 Hz 10 -12 mass fraction 238 U for meter-scale volume many, high- E particles { veto trigger: ionized electrons timing + fast relaxation Stack configuration: 84% of signal in 10 -7 solid angle cosmic rays: underground and/or muon scintillator (99.9%)