XMASS Experiment Masaki Yamashita Kamioka Observatory, ICRR, Univ

XMASS experiment Masaki Yamashita Kamioka observatory, ICRR, Univ. Of Tokyo On behalf of XMASS collaboration CIPANP2015 , 19th/May/2015

• Introduction of XMASS • XMASS 800 kg detector and calibration • Recent Result of XMASS • 129Xe inelastic • Bosonic super-WIMP search • status of annual modulation search • Future XMASS1.5 • XMASS 1.5 (1ton fducial, 5 ton LXe) Masaki Yamashita XMASS Experiment Multi purpose low-background experiment with LXe.

Xenon MASSive detector for Solar neutrino (pp/7Be) Xenon neutrino MASS detector (double beta decay) Xenon detector for Weakly Interacting MASSive Particles (DM)

XMASS%I% XMASS%1.5% XMASS%II% FV:100kg FV:1ton5ton FV:10ton24Ton

Masaki Yamashita The XMASS collaboration: Kamioka%Observatory,%ICRR,%the%University%of%Tokyo:%K.%Abe,%K.%Hiraide,%K.%Ichimura,%Y.%Kishimoto,%K.%Kobayashi,% M.%Kobayashi,%S.%Moriyama,%M.%Nakahata,%T.%Norita,%H.%Ogawa,%H.%Sekiya,%O.%Takachio,%A.%Takeda,%M.%Yamashita,% B.%Yang% Kavli%IPMU,%the%University%of%Tokyo:%J.Liu,%K.Martens,%Y.%Suzuki,%X.%Benda% Kobe%University:%R.%Fujita,%K.%Hosokawa,%K.%Miuchi,%Y.%Ohnishi,%N.%Oka,%Y.%Takeuchi% Tokai%University:%K.%Nishijima% Gifu%University:%%S.%Tasaka% Yokohama%National%University:%S.%Nakamura% Miyagi%University%of%Education:%Y.%Fukuda% STEL,%Nagoya%University:%Y.%Itow,%R.%Kegasa,%K.%Kobayashi,%K.%Masuda,%H.%Takiya% Sejong%University:%N.%Y.%Kim,%Y.%D.%Kim% KRISS:%Y.%H.%Kim,%M.%K.%Lee,%K.%B.%Lee,%J.%S.%Lee% Tokushima%University:%K.Fushimi

11 institutes 41 researchers. Masaki Yamashita Physics%results%of%XMASSXI Published ● Light%WIMP%search,%%Phys.&Lett.&B&719&(2013)&78& ● Solar%axion%search,%%Phys.&Lett.&B&724&(2013)&46& ● Bosonic%SuperXWIMPs,%%Phys.&Rev.&Lett.&113&(2014)&121301& ● Inelastic%scattering%on%129Xe,%%PTEP&2014,&063C01&

coming%soon ● Double%electron%capture%of%124Xe% ●Seasonal%modulation%with%full%volume%of%LXe% ●Fiducial%volume%analysis%for%heavy%WIMPs

!' -4 :(;"!012.!!!<%'!34!=''>#(&!34"012.? 10

#<@56!!!AB D#('$!#"C&#)E$ aee o-Ps "C, g Light Mass WIMPAB C&# $ -5 #$@56!!! "C,D$(<&!#" )E AB C&" $ 10 !;@56!!! "C,D&(&&!#" )E Solar Axion !& -6 reactors beam 10 dump Axio%electric+eﬀect -7 10 !% 169 -8 Tm 10 g 18GeV -9 aee !$ 10 Si(Li)

)*+,-./012/34/35655 -10 10 Ge XMASS 12GeV solar neutrino -11 EDELWEISS 4 !# 10 DFSZ 7GeV -12 KSVZ 10 Red Giants !" -13 !" !"(' !# !#(' !$ 10 -2 -1 2 3 4 5 6 7 10 10 1 10 10 10 10 10 10 10 5,5742!8356559 mass (eV) Physics Letters B 719 (2013) 78-82 Figure 7: Simulated WIMP energy spectra in the XMASS detector assuming thePhysics maximum Letters B 724 (2013) 46 Masaki Yamashita cross section that provides a signal rate no larger than the observation in any bin above 0.3 keVee.

12 •1000m%under%a%mountain%=%%%%%%%%%%%% 2700m%water%equiv.% •360m%above%the%sea% Kamioka mine •Horizontal%access% Gifu, Hida city, Ikenoyama •Experiment% •SuperXK%% •KamLAND%(Tohoku%U.)% •KAGURA%for% interferometer%% Kamland •NEWAGE super Kamiokande

ICRR, UTokyo Masaki Yamashita Yamashita water puriﬁcation system Experimental Hall

Rn: ~ 1mBq/m3 5ton/hour Distillation Tower

LXe Tank Water Tank Xenon Buffer Tank

entrance (clean room)

MasakiMasaki Yamashita Yamashita Water Shield

10 m

- φ10m x 10m ultra pure water shield with

20 inch x 70 PMTs for muon veto Masaki Yamashita XMASS Detector R10789

Activity per 1PMT(mBq/

238U-chain 0.70+/-0.28

232Th-chain 1.51+/-0.31

40K <5.1

60Co 2.92+/-0.16

- 642 ultra low background 2 inch PMTs - Largest detector: 832 kg of LXe for sensitive volume. Masaki Yamashita

Detector calibration

26 2012/12/21

SUS 0.21 side) (KRISS 68 122 57 - Co (4)

SUS 0.17 485 59.5 241 -

•-Inner calibrationCalibration system isOFHC copperfor rod and energy source calibration. Am (3)

stepping motor

brass 5 800 88 25, 22, 109 - on the tank top Cd (2)

brass 5 350 5.9 55 - guide pipe Fe (1)

material Outer [mm] Dia. [Hz] Intensity ] keV OFHC copper rod [ energy

moved along z−axis

Flange for

source exchange

gate valve 5

0 3 0

Figure 5: Calibration system on top of the tank. Source placedontheedgeofthecopper 3 rod is inserted into the ID and can be moved along the z axis.

Gate

Am 241

~5m valve

13 φ

109 Co Table 7: Calibration sources and energies. The 8 keV (*1) in the Cd and 59.3 keV (*2) 57

57 in the Co source are Kα X-rays from the copper and tungsten, respectively, used for

source housing. KRISS by made were sources Theses 0.21mm

Isotopes Energy [keV] Shape

55Fe 5.9 cylinder Sources 3. 109Cd 8(*1), 22, 58, 88 cylinder 241Am 17.8, 59.5 thin cylinder 57Co 59.3(*2), 122 thin cylinder 137Cs 662 cylinder Masaki Yamashita

21 Detector calibration •-High Photoelectron Yield ~15 PE/keV •-Good agreement between data and.

1 real data 0.8 57Cosimulation (MC) 0.6 15PE/keV @122keV 0.4 Total PE

0.2

Events (normalized) @R=-30cm Events (normalized) 0 0 20 40 60 80 100 120 140 reconstructedReconstructed energy [keVee] energy [keVee]

0.8 0.7 real data 0.6 simulation (MC) 0.5 0.4 Position 0.3 Normalized 0.2 0.1 Events (normalized) 0 -40 -30 -20 -10 0 10 20 30 40 reconstructedReconstructed z [cm] position (z) [cm] Masaki Yamashita

Figure 9: Energy spectra reconstructed using the 57Co source at z = 0cm (upper) and ver- tex distributions reconstructed using the same source at z = −40, −30,...,40 cm (lower).

26 Comparison%of%background%rate

■ Background%rate%in%the% fiducial%volume before%separation%of% nuclear%recoils%from%e/γ

■ XMASS%achieved%O(10X4)% XMASS event/day/kg/keVee at%a%few%10’s%keV.

Added%to%D.C.Malling%thesis%(2014)%Fig.1.5

Masaki Yamashita Search for 129Xe Inelastic scattering by WIMP ■ χ%+%129Xe%! χ%+%129Xe* not % 129Xe*%! 129Xe%+%γ%(39.6keV)% ■ Natural%abundance%of%129Xe:%26.4% X+N -> X* + N

(1)=%preXselection% (2)=%(1)%&%radius%cut% (3)=%(2)%&%timing%cut% Observed%data%(165.9%days) (4)=%(3)%&%band%cut

Signal%MC

Red:%XMASS%(90%%C.L.%stat.%only)% ✓ 40 keV+ nuclear recoil signal ~40keV mono- Pink%band:%XMASS%(w/%sys.%error)% energetic peak Black:%DAMA%LXe%2000%(90%%C.L.) ✓41 kg のfducial volume cut , 2010/12/24-2013/05/10 165.9 days data. ✓position information by PE and timing. ✓3pb at 100 GeV.(most stringent limit>80GeV） excitation cross section[pb] Masaki Yamashita Search for 129Xe Inelastic scattering by WIMP ■ χ%+%129Xe%! χ%+%129Xe* not % 129Xe*%! 129Xe%+%γ%(39.6keV)% ■ Natural%abundance%of%129Xe:%26.4% X+N -> X* + N

(1)=%preXselection% (2)=%(1)%&%radius%cut% (3)=%(2)%&%timing%cut% Observed%data%(165.9%days) (4)=%(3)%&%band%cut

Signal%MC

PTEP 2014,063C01 H.Uchidaetal.

-34 ]

2 10 ✓ 40 keV+ nuclear recoil signal ~40keV mono- energetic peak 10-35 CDMS ✓41 kg fducial volume cut , 2010/12/24-2013/05/10 10-36 165.9 days data. XMASS-I 10-37 ZEPLIN-III

✓position information by PE and timing. section [cm tron cross u 10-38 ✓3pb at 100 GeV.(most stringent limit>80GeV） XENON10 XENON100 ✓Form Factro(L.Baudis et al., PRD88,115014,2013) 10-39 SD WIMP–ne -40 Downloaded from a (V.D.Vergados et al., NPB 877,36(2013) 10 3 102 10 MasakiWIMP mass Yamashita [GeV]

Fig. 7. The thick line with its gray shaded systematic uncertainty band represents our limit using the form factors of Ref. [33], and the dots represent our limits following Ref. [34]forthatpaper’schoice of WIMP masses. The dashed, dotted, dash-dotted, and long dash-dotted lines represent experimental con- http://ptep.oxfordjournals.org/ straints on spin-dependent WIMP nucleon cross sections extracted from elastic scattering data as published in Refs. [38–41], respectively. Our own limit is the first derived exclusively from data on inelastic scattering. following Poisson statistics. This procedure was repeated to accumulate a histogram of the observed number of events for a fixed µ by sampling the signal efficiency within its systematic error. The 90% C.L. upper limit for µ is the one that results in a 10% probability of having five events or fewer.

Using Eq. 6, this is then translated to an inelastic WIMP nucleus cross section, and the variation at Kokusai Hoken Keikakugaku (UNIV OF TOKYO) on June 6, 2014 of our limit within our systematic uncertainties. Both are shown by the black line and gray band in Fig. 4,respectively. It should be noted that the constraint obtained by the DAMA group [12,13]wasderivedfrom a statistical evaluation of an excess above a large background of 2 10 2 keV 1 d 1 kg 1.We × − − − − achieved a lower background 3 10 4 keV 1 d 1 kg 1 using the cut discussed above. This low ∼ × − − − − background allowed us to avoid having to subtract background to obtain a competitive limit. Our limits that are based on the updated nuclear form factors given in Refs. [33,34]arealsousing the same data reduction and therewith event sample as those for the older form factors. The results shown in Fig. 7 are based on the inelastic structure factors for Sn(u) 1b+2b currents as shown in Fig. 1 of Ref. [33], and on the time-averaged differential scattering rate for inelastic scattering as shown in Fig. 4 of Ref. [34], the latter taken with a normalization of 17 fb2 for the total WIMP–nucleon cross section. Figure 7 also shows previous experimental limits for the spin-dependent WIMP–neutron cross section that were previously obtained by XENON10, CDMS, ZEPLIN-III, and XENON100 [38–41]. All of these existing limits are based on spin-dependent elastic scattering, while our analysis explicitly restricts itself to inelastic scattering on a nucleus.

6. Conclusion AsearchforinelasticscatteringofWIMPson129Xe was performed using data from our single- phase liquid-xenon detector XMASS. Events reconstructed in a spherical fiducial volume of 15 cm radius at the center of the detector containing 41 kg of LXe were used in this analysis. We observed no significant excess in 165.9 live days’ data and derived for e.g. a 50 GeV WIMP an upper limit of 3.2 pb at the 90% confidence level for its inelastic cross section on 129Xe nuclei using the form

2 This value was taken from Ref. [34]’s Ref. [46] and conﬁrmed with one of the authors of Ref. [34].

10/11 Search for Bosonic super-WIMPs

Phys.&Rev.&Lett.&113&(2014)&121301 v or a

• Candidate%Warm%Dark%Matter% • sterile%neutrino,%gravitino%…% • NO%SUSY%so%far.% Observed data + signal(MC) • Lighter%and%more%weekly%interacting%than% WIMPs% • It%can%be%pseudoscaler%or%vector%boson%and% in%this%case,%it%can%be%detected%by% absorption%of%the%particle, which%is%similar%to%the%photoelectric%effect.% • Search%for%monoXenergetic%peak%at%the% mass%of%the%particle% • same%data%set%as%inelastic%scattering%%%%%%%%%% 41%kg%%fiducial%volume%cut%,% 2010/12/24X2013/05/10%165.9%days%data.%

Masaki Yamashita week ending PRL 113, 121301 (2014) PHYSICAL REVIEW LETTERS 19 SEPTEMBER 2014

pseudoscalar case. For the vector super-WIMPs search, this where the subscript ee refers to the customary electron is the first direct detection experiment. The mass range equivalent energy deposit. This large photoelectron yield is of this study is restricted to 40–120 keV. At the low mass realized since the photocathode area coversweek ending> 62% of the PRLend,113, we are121301 limited (2014) by increasing background,PHYSICAL and at REVIEW high inner LETTERS wall with a large quantum19 efficiency SEPTEMBER of ∼ 201430% [5]. masses, the calculations in Ref. [1] are limited to the mass Data acquisition is triggered if 10 or more PMTs have pseudoscalarof the boson case. less For than the 100 vector keV. super-WIMPs search, this wheresignals the subscript larger thanee 0.2refers p.e. towithin the customary200 ns. Each electron PMT signal is the first direct detection experiment. The mass range equivalent energy deposit. This large photoelectron yield is The absorption of a vector boson is very similar to is digitized with charge and timing resolution of 0.05 p.e. of this study is restricted to 40 120 keV. At the low mass realized since the photocathode area covers > 62% of the the photoelectric effect when– the photon energy ω is and 0.4 ns, respectively [7]. The liquid-xenon detector is end, we are limited by increasing background, and at high inner wall with a large quantum efficiency of ∼30% [5]. masses,replaced the by calculations the vector in boson Ref. [1] massare limitedmV and to the the couplingmass Datalocated acquisition at the is center triggered of a if water 10 or Cherenkov more PMTs veto have counter, ofconstant the boson is lessscaled than appropriately. 100 keV. The cross section, there-signalswhich larger is than 11 m 0.2 high p.e. withinand has 200 a ns. 10 Each m diameter. PMT signal The veto fore,The becomes absorption[1] of a vector boson is very similar to is digitizedcounter with is equipped charge and with timing seventy-two resolution 50 of cm 0.05 PMTs. p.e. Data the photoelectric effect when the photon energy ω is andacquisition 0.4 ns, respectively for the veto[7]. counter The liquid-xenon is triggered detector if eight is or more replaced by the vector bosonσabsv mass m αand0 the coupling locatedof its at PMTs the center register of a signal water withinCherenkov 200 ns. veto XMASS-I counter, is the ≈V ; 1 constant is scaled appropriately.σphoto ω m TheV c crossα section, there- ð Þ whichfirst is direct 11 m detection high and dark hasa matter 10 m experiment diameter. The equipped veto with fore, becomes [1] ð ¼ Þ countersuch is an equipped active water with seventy-two Cherenkov 50shield. cm PMTs. Data acquisition for the veto counter is triggered if eight or more where σabs is the absorption cross section of the vector For both, vector and pseudoscalar type super-WIMPs, σabsv α0 of itsMonte PMTs register Carlo (MC)a signal signals within 200 are ns. generated XMASS-I by is the injecting bosons on an atom, v is the velocity≈ of; the incoming vector1 σ ω m c α ð Þ firstgamma direct detection rays uniformly dark matter over experiment the entire equipped active volume with with boson, σphoto is thephoto crossð ¼ sectionVÞ for the photoelectric effect, α is the fine structureBosonic constant, and α issuper-WIMPs the vector boson sucha an gamma active Search waterenergy Cherenkov corresponding shield.Results to the rest mass of the 0 For both, vector and pseudoscalar type super-WIMPs, whereanalogueσabs tois the the fine absorption structure cross constant. section For of a the single vector atomic boson [8]. This procedure exploits the experimentally bosons on an atom, v is the velocity of the incoming vector Monterelevant Carlo aspect (MC) that signals all the are energy generated of aby boson injecting including species of atomic mass A, the counting rate Sv in the gamma rays uniformly over the entire active volume with eventboson, σratephoto is the cross section for the photoelectric effect, its mass given to an electron is identical to that for gamma detector becomes [1] a gamma energy corresponding to the rest mass of the • α For%vector%boson%caseis the fine structure constant, and α%0 is the vector boson rays at these low energies, albeit with different coupling analogue to the fine structure constant. For a single atomic boson [8]. This procedure exploits the experimentally 23 σ constants in Eqs. (1) and (3). species of atomic4 × 10 massα0 keVA, the countingphoto rate1 S in1 the relevant aspect that all the energy of a boson including Sv ≈ kg− dayv − ; 2 In the present analysis, we scale the observed number of detectorvector becomes bosonA [1]α casemV barn ð Þ its mass given to an electron is identical to that for gamma raysphotoelectrons at these low energies, by 1=13 albeit.9 to withobtain different an event coupling energy E in where the standard23 local dark matter density of constantskeVee in, without Eqs. (1) and applying(3). the nonlinearity correction of 4 × 10 α0 keV σphoto 1 1 0.3SGeVv ≈ =cm3 [4] is used. Valid rangeskg− day for− the; couplings2 Inscintillation the present analysis, light efficiency. we scale The the observed MC simulation number ofincludes A α mV barn ð Þ and masses of thermally produced super-WIMPs are photoelectronsthis nonlinearity by 1=13 of.9 theto obtain scintillation an event response energy [5]E inas well wherecalculated the in standard Refs. [1,2] local. dark matter density of keVeeas, corrections without applying derived the from nonlinearity the detector correction calibrations. of The •0.3the%first%direct%search%in%the%40–120%keV%GeVThe= crosscm3 [4] sectionis used. of Valid the ranges axioelectric for the effect couplings for the scintillationabsolute light energy efficiency. scale of The the MC MC simulation simulation includes is adjusted at andpseudoscalarrange.% masses of on thermally the other produced hand is super-WIMPs are this122 nonlinearity keV. The of systematic the scintillation difference response of[5] theas energy well scale calculated in Refs. [1,2]. as correctionsbetween data derived and fromMC simulation the detector due calibrations. to imperfect The model- The cross section of the axioelectric2 effect for the absolute energy scale of the MC simulation is adjusted at • The%limit%excludes%the%possibility%that%such%σabsv 3ma ing of the nonlinearity in MC simulation is estimated as pseudoscalar on the other hand is ≈ ; 3 122 keV. The systematic difference of the energy scale σ ω m c 4παf2 ð Þ 3.5% by comparing 241Am data to MC simulation. The particles%constitute%all%of%dark%matter.%photoð ¼ aÞ a between data and MC simulation due to imperfect model- 2 decay constants of scintillation light and the timing σabsv 3ma ing of the nonlinearity in MC simulation is estimated as • whereFor%pseudoscaler%casema is the mass of the pseudoscalar≈ % 2 ; particle, and3 fa response of PMTs241 are modeled to reproduce the time σphoto ω ma c 4παfa ð Þ 3.5% by comparing Am data to57 MC simulation. The241 is a dimensionful couplingð ¼ Þ constant. The counting rate Sa decaydistribution constants observed of scintillation with the lightCo and (122 the keV) timing and Am now becomes [1] (60 keV) gamma ray sources [9]. The group velocity of the wherepseudoscalerma is the mass of thecase pseudoscalar particle, and fa response of PMTs are modeled to reproduce the time is a dimensionful coupling constant. The counting rate S distributionscintillation observed light with in liquid the 57Co xenon (122 is keV) calculated and 241Am from the 19 σ a now becomes1.2 ×[1]10 2 ma photo 1 1 (60 keV)refractive gamma index ray sources (∼11 cm[9]=ns. The for group 175 nm) velocity[10] of. the Sa ≈ gaee kg− day− ; 4 A keV barn ð Þ scintillationData taken light in in theliquid commission xenon is calculatedphase between from December the 19 σ 1.2 × 10 2 ma photo 1 1 refractive24, 2010 index and (∼11 Maycm= 10,ns for 2012 175 were nm) [10] used. for the present Sa ≈ gaee kg− day− ; 4 where gaeeA 2me=fa,keV with mbarne being the electron mass. Dataanalysis. taken inWe the selected commission the periods phase between of operation December under what ¼ ð Þ • The%most%stringent%direct%constraint%on%XMASS-I is a large single-phase liquid-xenon detector 24,we 2010 designate and May normal 10, 2012 data were taking used conditions for the presentwith a stable where[5] locatedgaee underground2me=fa, with (2700me being m water the electron equivalent) mass. at the analysis.temperature We selected (174 the1 periods.2 K) and of pressure operation (0.160 under what0.164 MPa gaee.¼ – KamiokaXMASS-I Observatory is a large single-phase in Japan. An liquid-xenon active target detector of 835 kg we designateabsolute). normal We have dataÆ further taking removed conditions the with periods a stable of oper- [5]oflocated liquidxenon underground is held (2700 inside m of water a pentakis-dodecahedral equivalent) at the temperatureation with (174 excessive1.2 K) PMT and noise,pressure unstable (0.160– pedestal0.164 MPa levels, or Æ Kamiokacopper Observatorystructure that in Japan. holds An 642 active inward-looking target of 835 photo- kg absolute).abnormal We triggerhave further rates. removed Total live the time periods is 165.9 of oper- day. ofmultiplier liquid xenon tubes is held (PMTs) inside on of its a pentakis-dodecahedral approximately sphericalation withEvent excessive selection PMT proceeds noise, unstable in four stages pedestal thatMasaki levels, we refer or Yamashita to as copperinner structure surface. Thethat holds detector 642 is inward-looking calibrated regularly photo- by abnormalcut-1 triggerthrough rates. cut-4. Total Cut-1 live requires time is 165.9 that no day. outer detector multiplier tubes (PMTs) on its approximately spherical inserting 57Co and 241Am sources along the central vertical Eventtrigger selection is associated proceeds with in four the events, stages that that we they refer are to separated as inner surface. The detector is calibrated regularly by cut-1 through cut-4. Cut-1 requires that no outer detector axis of the detector. Measuring with the 57Co source from from the nearest event in time by at least 10 ms, and that the inserting 57Co and 241Am sources along the central vertical trigger is associated with the events, that they are separated axisthe of center the detector. of the detector Measuring volume with the the57 photoelectronCo source from yieldfromrms the spread nearest of event the in inner time detector by at least hit 10 timings ms, and contributing that the to is determined to be 13.9 photoelectrons p:e: =keV [6], the trigger is less than 100 ns. These criteria eliminate the center of the detector volume the photoelectronð Þ yieldee rms spread of the inner detector hit timings contributing to is determined to be 13.9 photoelectrons p:e: =keV [6], the trigger is less than 100 ns. These criteria eliminate ð Þ ee 121301-2 121301-2 Modulation analysis data set

ID Trig : Nhit>= 4, ID only WIMP signal dT(pre)>10ms: veto 10ms after the event efﬁciency T-RMS : timing RMS of event (<100ns) Cherenkov cut: nhit in ﬁrst 20nsec < 60% Max/PE cut : maxpt/total pe cut NO PARTICLE ID (both nuclear/electronic recoil)

keVee(scaled@122keV)

live time 359.20 days x 832 = 298854.40 kg days 103

ID Trig :(34751119, 1.000, 1.000) dT(pre)>10 ms:(30348199, 0.873, 0.873) 2 T-RMS<100ns:(29049563, 0.836, 0.957) 10 Cherenkov cut :(1902854, 0.055, 0.066) 0.82 ton・year exposure Max/PE cut :( 370250, 0.011, 0.195) 10

1 rate [counts/day/kg/keVee] rate

10-1

10-2

10-3 0 2 4 6 8 10 2013 2015 energy [keVee] Masaki Yamashita Detector Performance Energy Calibration and its physical parameters. After power cut at 2014/8, the PE yield dropped ~5%. This change effect on the efﬁciency for the cuts due to the position dependency in whole detector. Those uncertainty of detector response is taken into account as systematic error by Monte Carlo.

PE/keV (calibration data, R=30cm) Light Yield of LXe

~5% power cut accident Yield LIght

1.1

Absorption length in LXe 1.05

0.95

relativeefﬁciency uncertainty 0.9

0.85 AbsorptionLength 15 15.2 15.4 15.6 15.8 pe yield [pe/keV] Masaki Yamashita Annual modulation analysis

0.5-1.0 keV 1.0-1.5 keV 1.5 0.5-1.0 keVee (-> 4.8-8.0 keVr) 0.7 1.0-1.5 keVee (->8-10.5 keVr) 0.65 1.45

-40 2 0.6 1.4 8GeV, 3x10 cm 0.55 1.35 0.5 1.3 Rate [counts/day/kg/keV] Rate [counts/day/kg/keV] 0.45 1.25 0.4 1.2 cpd/kg/keVee

XMASS data cpd/kg/keVee 0.35 XMASS data 1.15 w/ow/o systematic systematic w/o systematic 0.3 0 100 200 300 400 500 1.1 0 100 200 300 400 500 Day from 2014.Jan.1 Day from 2014.Jan.1

-World’s largest mass 1%year%data%of%XMASS%(0.82%ton*year)%%%vs.%%14%years% data%of%DAMA/LIBRA%(1.33%ton*year)% →%%Current%staosocs%is%already%half%of%DAMA/LIBRA% data.% XLow energy threshold: 0.5 keVee by 122keV (-> s4.8keVr, 1keVee true energy) -Achieving without particle ID (DM, axion like particle, mirror dm etc ). This threshold will be lower down to 3keVr in the future. The results for 1 year data will come soon. Masaki Yamashita annual modulation analysis

0.5-1.0 keVee(= 4.8-8.0 keVr) 1 2.2 0.9 1.0-1.5 keVee (= 8-10.5 keVr) 2 0.8 -40 2 1.8 10GeV, 3x10 cm 0.7 1.6 0.6 1.4 0.5 1.2 Rate [counts/day/kg/keV] 0.4 1 0.3 0.8 cpd/kg/keVee

XMASS data cpd/kg/keVee 0.2 XMASS data 0.6 w/o systematic w/o systematic 0.1 0.4 0 0 100 200 300 400 500 0 100 200 300 400 500 Day from 2014.Jan.1

- to improve sensitivity for next phase, dome shape PMT has been developed to solve the problem of surface events. - 180° ﬁeld view - pure Al seal (> 3 order magnitude lower U) R10789%5.6nsec%→R13111%<3.5nsec% - - goal%is%1/10%of%%R10789 radioactivity - Test in LXe is going on. -1ton ﬁducial, 5 ton total PMT -46 2 - <10 cm at 100 GeV. -Inherit current water shield -XMASS 1.5 design study is on going. Masaki Yamashita Summary • Recent Result from XMASS • Inelastic 129Xe • 3pb at 100 GeV.(>80GeV, most stringent limit） • bosonic Super WIMP • vector-boson warm dark matter was ruled out in the 40-80 keV. • status Annual modulation • final result coming soon • XMASS1.5 design is on going. • 3inch dome shape PMT Masaki Yamashita