Detec%on prospects for the Cosmic Neutrino Background using laser - PowerPoint PPT Presentation

Detec%on prospects for the Cosmic Neutrino Background using laser interferometers Mar$n Spinrath Na$onal Center for Theore$cal Sciences The 3rd KAGRA Interna$onal Workshop - 21/05/2017 Based on collabora$on with Valerie Domcke, arXiv:1703.08629

CNB Introduc$on • Produced 1 s aXer Big Bang (CMB: 379k years) • Number density: 330 cm -3 • Temperature: 1.9 K • Energy: 0.16 meV • Velocity: 10 -3 - 1 c • CNB cross sec$on to neutrons: 10 -27 pb Mar$n Spinrath (NCTS) 21/05/17 - KIW3 CNB Detec$on Prospects 2

The Experiment [Domcke, MS '17] • Pendulum in neutrino wind 
 a ν � g Pendulum l d θ • LIGO-like interferometers 
 l CNB wind a ν � 10 − 16 ���� 2 Interferometer • Einstein telescope maybe d a ν � 3 · 10 − 18 ���� 2 Mar$n Spinrath (NCTS) 21/05/17 - KIW3 CNB Detec$on Prospects 3

Theory: Magne$c Torque [Domcke, MS ’17; see also Duda et al. '01] • Neutrino background splits electron energy levels (spin effect ➞ magne$c effect) √ 2 2 N AV γ � a R G F = ( n ν α − n ¯ ν α ) g α G F β ��� A ⊕ A m AV R π α = e,µ, τ • For one flavour ν µ − n ν µ G F ≈ 4 · 10 − 29 n ¯ ���� 2 a R 2 ¯ n ν • Caveats: • Experimentally difficult (magne$c effect) • Needs lepton asymmetry Mar$n Spinrath (NCTS) 21/05/17 - KIW3 CNB Detec$on Prospects 4

Theory: Scaeering I [Domcke, MS ’17; see also Duda et al. '01] • The basic formula N AV N c σ ν − A � ∆ p � a G 2 F = Φ ν A m AV • Incoming flux: Φ ν • #nuclei in 1g test material: N AV / ( Am A V ) • Neutrino-nucleus cross-sec$on: σ ν − A • Coherence factor: N c • Average momentum transfer: � ∆ p � Mar$n Spinrath (NCTS) 21/05/17 - KIW3 CNB Detec$on Prospects 5

Theory: Scaeering II [Domcke, MS ’17; see also Duda et al. '01] • Neutrinos can come in three kinema$cs • rela$vis$c (R) • non-rela$vis$c non-clustered (NR-NC) • non-rela$vis$c clustered (NR-C) • Two important numbers • The cross-sec$on: σ ν − A ≈ 10 − 27 �� = 10 − 63 �� 2 N AV • The coherence factor: ρ λ 3 ν ∼ 10 20 N c = A m AV Mar$n Spinrath (NCTS) 21/05/17 - KIW3 CNB Detec$on Prospects 6


 
 
 
 Theory: Scaeering III [Domcke, MS ’17; see also Duda et al. '01] • Results for the three kinema$cal cases: 
 3 · 10 − 33 ���� 2  ��� ��� ,  F = n ν  5 · 10 − 31 ( m ν / 0 . 1 ��� c 2 ) ���� 2 a G 2 ��� ������� , 2 ¯ n ν 2 · 10 − 27 (10 − 3 / β ��� ) ���� 2  ��� ������ ,  • Compare to experimental sensi$vity: a ν � 10 − 16 ���� 2 Mar$n Spinrath (NCTS) 21/05/17 - KIW3 CNB Detec$on Prospects 7

Other "Winds" [Domcke, MS ’17; see also Duda et al. '01] • Solar neutrinos a ����� − ν ≈ 3 · 10 − 26 ���� 2 • Cold WIMP Dark Maeer (m X > 1 GeV) � � ρ ����������� � � β X � 2 � ( A − Z ) 2 � � σ X − N ���� 2 a �� ≈ 4 · 10 − 30 10 − 46 �� 2 10 − 24 � / �� 3 10 − 3 76 A • Light WIMP Dark Maeer (m X = 3.3 keV) [See also Graham et al. '15] a ����� �� ≈ N c a �� ≈ 10 9 a �� Mar$n Spinrath (NCTS) 21/05/17 - KIW3 CNB Detec$on Prospects 8

Wind vs. Nudges I [Domcke, MS ’17] • The scaeering rate a G 2 F R = � ∆ p � • Numbers for the CNB R ��� ≈ 1 · 10 − 4 n ν � − 1 � − 1 2 ¯ n ν R ������� ≈ 0 . 02 n ν m ν 0 . 1 ��� c 2 � − 1 � − 1 2 ¯ n ν � 2 0 . 1 ��� c 2 � 10 − 3 R ������ ≈ 0 . 4 n ν � − 1 � − 1 β ��� 2 ¯ n ν m ν Mar$n Spinrath (NCTS) 21/05/17 - KIW3 CNB Detec$on Prospects 9


 Wind vs. Nudges II [Domcke, MS ’17] • Solar neutrinos R ����� − ν ≈ 2 · 10 − 9 � − 1 � − 1 • Cold WIMP Dark Maeer (m X > 1 GeV) � � ρ ����������� � � β X � 100 ���� c 2 � � � σ X − N R �� ≈ 8 · 10 − 3 � − 1 � − 1 10 − 33 �� 2 10 − 24 � / �� 3 10 − 3 m X • Light WIMP Dark Maeer (m X = 3.3 keV) 
 � � ρ ����������� � � β X � 4 � � 3 . 3 ���� c 2 � σ X − N R ����� �� ≈ 4 · 10 5 � − 1 � − 1 m X 10 − 42 �� 2 10 − 24 � / �� 3 10 − 3 Mar$n Spinrath (NCTS) 21/05/17 - KIW3 CNB Detec$on Prospects 10

Improvements and Alterna$ves [Domcke, MS '17] • Sensi$vity propor$onal to g factor • Suspension • Space • Give up on pendulum setup • free falling masses and wait • Alterna$ves to mechanical force experiment • Inverse beta decay (PTOLEMY) • … Mar$n Spinrath (NCTS) 21/05/17 - KIW3 CNB Detec$on Prospects 11

Summary and Conclusions • Cosmic Neutrino Background is interes$ng… • … but difficult • Laser interferometers cannot see the CNB… • … but maybe other cosmic winds • … or cosmic nudges Mar$n Spinrath (NCTS) 21/05/17 - KIW3 CNB Detec$on Prospects 12

Dream Big! (but whom am I telling…) Mar$n Spinrath (NCTS) 21/05/17 - KIW3 CNB Detec$on Prospects 13