Search for DM in the form of Axion-like particles ( ALPs ) and Hidden - PowerPoint PPT Presentation

Search for DM in the form of Axion-like particles ( ALPs ) and Hidden Photon ( HPs ) in the XMASS detector Kazufumi Sato (Nagoya Univ.) for the XMASS collaboration 10 Sep. 2019 @ TAUP2019 in Toyama contents • introduction • XMASS experiment • search for HPs and ALPs

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ALPs & HPs WISPs are candidate of cold DM Hidden Photon (HP) : gauge boson of hidden U(1) Axion-like particles (ALPs) : pseudo-Nambu-Goldstone boson • wide mass region is allowed for these bosons HP parameter space [P. Arias et al, JCAP06(2012)013] relatively weak limits around O(10)-100 keV/c 2 compared to 10 eV-10 keV = sensitive region for Direct DM search experiment log 10 (M HP [eV]) 3 1keV 100keV

principle of Direct DM search • Search for the interaction of DM with a scintillating target DM Main physics target is WIMP s DM WIMPs with nuclear recoil (NR) • DM + N Xe → DM + N Xe Plus, has a sensitivity for DMs causing electron recoil nucleus or e - various DM with e - recoil (ER) • DM + e - → e - (+ DM) HPs and ALPs are this type XMASS experiment target: 832 kg of liquid Xe = ~45 photon /keV ( ~ NaI) • surrounded by PMTs PMT 4

XMASS experiment 5

XMASS Direct DM search Experiment in Kamioka Observatory • 1000 m underground under Mt. Ikenoyama (= 2700 m.w.e) → shield cosmic rays 13 institutes, ~40 participants KamLAND Super-K CANDLES IBS • XMASS U of Tokyo, ICRR • KRISS • (Lab-C) Lab2/EGad U of Tokyo, IPMU Kavli • Kobe U. • Tohoku U. • Tokushima U. • Tokai U. • Yokohama National U. IPMU Lab1 • CLIO NEWAGE Miyagi U. of Education • Tsinghua U. • Nagoya U • Nihon U. • 6

Detector Outer Detector (Water Cherenkov detector) • veto & shield for external radiation Inner Detector • holds 832 kg liquid Xe • covered by 642 PMTs • High light yield ~ 15 p.e./keV 80cm 11m 10m Low RI PMT (HAMAMATSU R10789) 7

Self shielding BG : β / γ ’s from RIs in PMTs → shielded by LXe itself. • reconstruct the event vertex from PMT PMT holder surface hit pattern, and select R < 30 cm region Liquid Xe (att. L= 2.5 mm Event rate VS radius for 122 keV γ ) (E: 40-180 keV) 3 10 event rate [1/kg/day] Fiducial 2 10 Volume reject 10 R<30cm Evt rate: 1 RI in/on det. comp. ~5 × 10^-4 -1 10 /day/kg/keV -2 10 RI in Xe -3 10 inner region is kept in n-activated Xe 0 0.5 1 low BG environment! 3 3 R /(42.6 cm) 8

Status of XMASS 2010 2011 2012 2013 2014 ~ 2019.3 Nov. Dec. May commissio- refurbish- constr- continuous data taking ning run ment uction events [/day/keV/kg] Commissioning run identify run after refurbishment BG source Put Cu cover on the Al seal energy [keV] stable operation Al seal > 5 years 9

Status of XMASS 2010 2011 2012 2013 2014 ~ 2019.3 Nov. Dec. May commissio- refurbish- constr- continuous data taking ning run ment uction today’s topic previous result improved results ALPs and HPs search with stable 2.5 yeas data [ PLB 724 46 (2014) ] [ PLB 787 153 (2018) ] • commissioning data • data after refurbishment • = higher BG • 800 days × 327 kg • 132 days x 41 kg x 50 exposure 10

ALPs & HP search 11

HPs & ALPs signal HP ALPs A 0 HP kinetic mixing g Ae γ e � e � HP analogue of α σ pe ( ω = m ALP ) c = 3 m 2 σ abs v ALP g 2 σ pe ( w = m HP ) c = α 0 σ abs v Ae 16 πα m 2 e α expected E spectrum of ALPs cross-section of photoelectric effect 40 50 60 70 80 90 100 110 120 [M. Pospelov, et al., PRD 78, 115012 (2008)] [1/day/kg/keV] /kg/day] 10 -3 E [keV ] α ’/ α = 4 x 10^-26 a -3 10 m ALP =50 keV/c 2 a event rate [1/keV Both bosons couple with electrons 70 keV/c 2 90 keV/c 2 -> absorption analogous to 110 keV/c 2 10 -4 -4 10 photoelectric effect ➡ peak at the rest mass in E spectrum Event rate ∝ α ’/ α / m HP ∝ g Ae2 × m ALP 10 -5 -5 10 500 1000 1500 12 NPE cor

peak search make advance in our BG understanding → peak search by fitting the observed E spectrum with BG MC and signal MC • m = 40 - 120 keV/c 2 , fit range: 30 - 180 keV rate of… data BG MC signal MC E spectrum in Fiducial V. 40 60 80 100 120 140 160 180 � 2 � R i obs − R i BGtot − R i /kg/day] N bin HP ( m HP , κ ) E [keV ] a � χ 2 + χ 2 m HP , κ ≡ sys , σ 2 obs + σ 2 1 a dead 131m Xe BGtot /keV i tube for calibration signal -3 event rate [10 (90%CL) to deal sys. errors 125 I � R BGtot = p j R j -th BG , 0.5 j :RI types fit parameter BG rate from each RI RI in Xe scan mass and α ’/ α (or g Ae2 ) 0 • mass: every 2.5 keV, α ’/ α : 350 fine steps 500 1000 1500 2000 2500 NPE cor 13 I in Xe

systematic errors p j , Δ C m : fit parameters 1 σ uncertainty for MC paramters j � 14 C , 39 Ar � 2 � 2 � 1 − p j � ∆ C m • non-linearity of Xe light yield � � χ 2 sys = + , δ p j δ C m m j :RI types non-lineartiy from source calibration ) a (relative to 122.1 keV 1 σ uncertainty of RI amount 1 57Co Data/MC of NPE RI in the detector materials 0.9 • • screening by Ge detector 0.8 • analysis for the data 241Am 0.7 spectrum including high-E 0.6 events in full volume 85 Kr, daughter of 222 Rn 0.5 • 50 100 • delayed coincident energy of ray [keV] a • Energy resolution eg) 214 Bi - 214 Po in Rn chain • • position resolution • RI induced by thermal neutron • mis-reconstruction events • measurement for thermal due to dead PMTs neutron flux in the mine 14

☜ ☜ Result didn’t find any finite peak -11 10 Ae g Ae (ALPs) . o m g e D a -> set 90%CL upper limit n a r o j a M XENON100 10 -12 -12 10 prev. work LUX • cover higher mass region 10 -13 PandaX-II -13 10 than LUX, PandaX this work -14 10 2 10 -22 10 Majorana Demo. α ’/ α _ • cover a region where the (HP) ’/ 2 ALPs mass [keV/c ] _ -23 10 XENON100 limits from indirect searches 10 -24 -24 10 is relatively weak. HB diffuse ! prev. work 10 -25 -25 10 • The limit improves by factor 10 -26 -26 10 10~50 from our previous 10 -27 G -27 this work 10 R work -28 10 best limit in 40-120 keV/c 2 2 10 2 HP / ALPs mass [keV/c ] [light blue: H. An et al., PLB 747 331(2015)] 15

Summary • XMASS : direct DM search using ~800 kg liquid Xe • low BG environment including ER events. • sensitive for electron-scattering DM like HPs and ALPs • >5 years stable operation • search for Axion-like particles and Hidden Photons • direct detection through absorption analogue to photoelectric effect • several improvement from the previous measurement • increase in exposure by × 50 • improved BG understanding → enable to fit the observed E spectrum by MC • set upper limit on α ’/ α of HP and g Ae of ALPs • present the best limits in 40 < mass < 120 keV/c 2 16

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Detector Outer Detector (Water Cherenkov detector) • 10-m Φ × 11 m height • 72 20-inch PMTs • Active veto for cosmi. μ • Passive shield for external neutrons & γ ’s OFHC Copper vessel 80cm • hold liquid xenon • vacuum insulation 11m • keep at ~100 ℃ Inner Detector 10m 18

cont. Inner Detector (Liquid Xenon detector) • 832 kg LXe sensitive volume 80 cm • sphere of 80 cm in dia. HAMAMATSU spread over the • 642 2-inch PMTs R10789 inner surface • high QE: 28~39% • photo. coverage > 62% • High light yield: • ~15 p.e / keV • low RI 238 U chain 1.2 232 Th chain < 0.78 [mBq/PMT] 40 K 9.1 60 Co 2.8 19

physics results other DM with ER WIMPs with NR other physics 2010 2011 2012 2013 2014 2015 2016 Dec. May Nov. continuous data taking commissio- refurbish- constr- limits on WIMP cross section 10 -39 ning run ment WIMP-nucleon cross section [cm 2 ] uction DAMA/LIBRA (Na) 10 -40 CoGeNT (2013) XMASS (2013) CDMS-Si (2014) 10 -41 XMASS mod. XMASS mod. 10 -42 (2017) XMASS FV (2018) This work 10 -43 ) 8 1 0 2 ( 0 5 e - d low mass WIMP i S k r LUX (2017) a 0 D 10 -44 S 0 u 6 3 p P e WIMP search in A r E C D D M 7 ) S 1 PLB 719 78 (2013) 0 2 ( 10 -45 I - I X a d n a fiducial volume P XENON1T (2017) 10 -46 Inelastic WIMP arXiv:1804.02180(2018) 10 -47 10 1 10 2 10 3 10 4 scattering WIMP mass [GeV/c 2 ] PTEP 063C01 (2014) WIMP annual modulation PLB 759 64 (2016) bosonic super WIMPs ALPs and HPs PRD 97 102006 (2018) PLB 724 46 (2014) PLB 787 153 (2018) 2 ν ECEC Inelastic WIMP scattering 2 ν ECEC PLB 759 272 (2016) XXXXXX (2019) PTEP 053D03 (2018) solar axion Solar KK axion sub-GeV DM PLB 724 46 (2013) PTEP 103C01 (2017) XXXXXX (2019) 20

low BG environment Event rate VS radius event rate including ER events (40-180 keV E deposit) event rate [1/day/kg/keV] 3 10 event rate [1/kg/day] 10 2 10 1 reject 10 10 -2 1 RI in/on det. comp. -1 10 -4 10 XMASS%I -2 LUX-ZEPLIN (Xe 5.6 Tonne Fid.) ! 10 RI in Xe pp solar dominates 10 -6 -3 10 n-activated Xe 10 100 1000 E[keV] 0 0.5 1 avid Malling, Brown, for preparing slide Original figure taken from 3 3 R /(42.6 cm) D.C. Malling, Ph.D(2014) Fig1.5 R<30cm event rate is ~5 × 10^-4 /day/kg/keV ( inside fiducial volume, at E = 10s ~ 100 keV ) 21