Axion search with Dark Matter detector Paolo Beltrame Durham IPPP, 14th March 2016 1
Direct DM search Dark matter (DM) Milky Way s halo => flux on Earth ~ 10 5 cm -2 s -1 ρχ ~ 0.3 GeV/cm 3 and 100 GeV/c 2 Basic goal: search for nuclear recoil from DM elastic scattering. Simple dynamics: cross section (form-factor) 2 Spin-independent: nucleon form-factor gives rise to A 2 enhancement due to coherence. The dependence on q 2 is also contained in the form-factors. Spin-dependent: form-factor depends on nuclear spin. No coherence enhancement. 2
S1, S2 and CES Liquid xenon / dual-phase time projection chamber (TPC) (Ionisation) S2 1 μs (Scintillation) S1 100 ns 3
S1, S2 and CES Liquid xenon / dual-phase time projection chamber (TPC) (Ionisation) S2 100 ns 1 μs (Scintillation) S1 4 Combined Energy scale E = 1 S1 L(E) + S2 W g 1 g 2 W = 13.7 ev g1 = Light Collection g2 = Extraction + Light Eff. L(E) = Lindhard Factor Nuclear recoil enhancement of heat relative to electron recoils
Nuclear vs. Electron recoil Combination of Scintillation (S1) and Ionisation (S2) event-by-event particle identification Electron Recoil (ER) events Nuclear Recoil (NR) events 2.5 (a) Tritium ER Calibration ER calibration data log10log (S210 /S1) x,y,z corrected b (S2/S1) 2 1.5 1 0.4 kevee 0.8 1.3 1.8 2.4 2.9 3.5 4.1 4.6 2.5 (b) AmBe and Cf 252 NR Calibration NR calibration data 2 1.5 1 3 kevnr 0 6 9 10 12 15 18 21 20 30 S1 x,y,z corrected (phe) 24 40 27 50 S1 5 FIG. 3. Calibrations of detector response in the 118 kg fiducial
Spin-independent arxiv:1512.03506 10-38 cm 2 Z exchange 10 2 2 Z pb Higgs exchange 10 8 2 h pb Limit on Spin-Independent WIMP-nuclei at 6 x 6 10-46 cm 2 at 33 GeV/c 2
LZ = LUX + ZEPLIN Counts: 31 Institutions 200 Headcount Center for Underground Physics (Korea) LIP Coimbra (Portugal) MEPhI (Russia) Edinburgh University (UK) University of Liverpool (UK) Imperial College London (UK) University College London (UK) University of Oxford (UK) STFC Rutherford Appleton, and Daresbury, Laboratories (UK) University of Sheffield (UK) 7 University of Alabama University at Albany SUNY Berkeley Lab (LBNL) Brookhaven National Laboratory University of California Berkeley Brown University University of California, Davis Fermi National Accelerator Laboratory Lawrence Livermore National Laboratory University of Maryland Northwestern University University of Rochester University of California, Santa Barbara University of South Dakota South Dakota School of Mines & Technology South Dakota Science and Technology Authority SLAC National Accelerator Laboratory Texas A&M Washington University University of Wisconsin Yale University
The detector (LUX): world leading Generation-1 experiment, Sanford Underground Research Facility (SURF), 250 kg of active LXe target Cathode high voltage feedthrough LUX-ZEPLIN (LZ): Generation-2 flagship experiment for Direct Detection in US and UK, 7 tonnes of active LXe target arxiv:1509.02910 Existing water tank Outer Detector Gd-loaded liquid scintillator Outer Detector PMTs 7 tonne active LXe TPC PMTs: 488 Skin PMTs: (192) LXe heat exchanger 8
LZ timeline Year Month Activity 2012 March LZ (LUX-ZEPLIN) collaboration formed September DOE CD-0 for G2 dark matter experiments 2013 November LZ R&D report submitted 2014 July LZ Project selected in US and UK 2015 April DOE CD-1/3a approval, similar in UK Begin long-lead procurements (Xe, PMT, cryostat) 2016 April DOE CD-2/3b review 2017 February LUX removed from underground 2017 July Begin surface assembly prep @ SURF 2018 May Begin underground installation 2019 April Begin commissioning 2021 Q3FY21 CD-4 milestone (early finish July 2019) 2025 Planning on ~5 year of operations 9
Projected sensitivity Simulated LZ experiment (1000 days, 5.6 tonnes fiducial) (arxiv:1509.02910) Baseline σsi = 2.2 x 10-48 cm 2 B-8 = 7 ATM ν = 0.4 Goal σsi = 1.2 x 10-48 cm 2 B-8 = 220 ATM ν = 3 10
Projected sensitivity Simulated LZ experiment (1000 days, 5.6 tonnes fiducial) (arxiv:1509.02910) Baseline σsi = 2.2 x 10-48 cm 2 B-8 = 7 ATM ν = 0.4 Goal σsi = 1.2 x 10-48 cm 2 B-8 = 220 ATM ν = 3 New sensitivity study performed with updated low E LXe response and with PLR instead of Feldman-Cousins 10
Direct detection timeline Ge, NaI no discrimination Ge, w/discrim. ZEPLIN-III LXe, w/discrim. LUX CDMS Darkside SCDMS DEAP XENON 1T LZ 2 10-48 cm 2 (XENON nt) 11
Axion with DM direct search experiment 12
Publications K. Arisaka, P. Beltrame et al., Astroparticle Physics 44 (2013) 59 67 M. Pospelov et al., Phys. Rev. D 78 (2008), 115012 E. Aprile et al. (XENON100), Phys. Rev. D90 (2014), 062009 13
Theory Experimental detection with Invisible axion could be the QCD axion solving the CP violation problem xenon Axions and axion-like particles can couple with electron (gae) Axion-Like Particle, introduced by several extension of the SM, are good Dark Matter candidates Sources: - Solar Axion from Sun - Axion-Like particle slowly moving within our galaxy 14
Axio-electric effect Axion-Like particles Experimentally detectable in the Xe exploiting the axion-electric effect (proportional to the photoelectric effect) Ae = pe (E A ) g Ae 2 A 3E A 2 16 em m e 2 1 2/3 A 3! A Z +,e- g Ae e- Z +,e- A.V. Assuming Galactic 15
Axio-electric effect (solar) Production from Sun J. Redondo, JCAP12 (2013) 008 Solar flux (gae = 1 x 10-10 ) Detection within the detector photo-electric cross section for xenon Valid up to 1 kev Ae = pe (E A ) g Ae 2 A 3E A 2 16 em m e 2 1 2/3 A 3! 16
17 Astroparticle Physics 44 (2013) 59 67
Solar Axion 0 kev mass S2 AXION pdf 3 200 10 axioneventdensity 10 Entries 592648 7 180 160 140 0 kev mass Mean x 11.21 Mean y 1.393e+04 RMS x 8.142 6 RMS y 5636 5 6 120 100 4 Ae = pe (E A ) g Ae 2 A 3E A 2 16 em m e 2 1 2/3 A 3! 80 60 40 20 3 2 1 0 0 20 40 60 80 100 120 140 160 180 200 S1 0 18
Solar Axion Preliminary 19
Galactic ALPs S2 S2 AXION pdf 3 200 10 axioneventdensity 10 Entries 997557 45 180 Mean x 12.46 Mean y 1.533e+04 RMS x 4.006 40 160 RMS y 2034 35 140 120 100 80 60 40 20 0 0 20 40 60 80 100 120 140 160 180 200 S1 3 200 10 axioneventdensity 10 Entries 1000000 180 Mean x 74.64 0.5 Mean y 6.098e+04 RMS x 12.29 160 RMS y 1.038e+04 140 0.4 120 100 80 60 AXION pdf 30 25 20 15 10 5 0 0.3 0.2 6 6 S2 AXION pdf 3 200 10 axioneventdensity 10 Entries 1000000 2.2 Mean x 44.68 180 Mean y 2 3.673e+04 RMS x 8.641 160 1.8 RMS y 6294 5 kev mass 15 kev mass 140 120 100 80 60 40 20 0 0 20 40 60 80 100 120 140 160 180 200 S1 AXION pdf 3 200 10 axioneventdensity 10 Entries 1000000 0.9 Mean x 105.1 180 Mean y 8.469e+04 0.8 RMS x 15.73 160 RMS y 1.436e+04 0.7 140 25 kev mass 35 kev mass S2 120 100 80 60 1.6 1.4 1.2 1 0.8 0.6 0.4 0.2 0 0.6 0.5 0.4 0.3 6 6 40 0.1 40 0.2 20 20 0.1 0 0 20 40 60 80 100 120 140 160 180 200 S1 0 20 0 0 20 40 60 80 100 120 140 160 180 200 S1 0
Galactic ALPs Preliminary 21
Summary Dual-phase Xe DM direct detector are suitable for axion searches Proven by XENON100 (E. Aprile et al. (XENON100), Phys. Rev. D90 (2014), 062009) Sensitivity to gae Issue: signal sitting exactly where the dominant background is (ER events) 22