FERMILAB-SLIDES-18-140-AE -E Doping liquid xenon with light elements Hugh Lippincott, Fermilab COFI November 29, 2018 This manuscript has been authored by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics. 1
SuperCDMS Soudan Low Threshold XENON 10 S2 (2013) 10 � 39 10 � 3 CDMS-II Ge Low Threshold (2011) PICO250-C3F8 CDMSlite CoGeNT (2012) 10 � 40 10 � 4 (2013) CDMS Si (2013) SIMPLE (2012) 10 � 41 10 � 5 WIMP � nucleon cross section � cm 2 � COUPP (2012) WIMP � nucleon cross section � pb � DAMA ) 2 1 0 2 ( I I I - N I 10 � 42 C L 10 � 6 CDMS II Ge (2009) P E R Z E S S S T u Xenon100 (2012) p e EDELWEISS (2011) r C 10 � 43 D 10 � 7 M S S N ) 3 O 1 L N A B 0 SuperCDMS Soudan 2 E U ( X U 0 L 5 T e d 10 � 44 10 � 8 R I N S i k r a I 3 D F C O C - 0 5 7 Be y 2 C A T a T E O O H d - C S 0 E R T R I 0 P E N 3 I SuperCDMS SNOLAB X Neutrinos U N 8 B L 10 � 45 10 � 9 G T 1 n o Neutrinos DEAP3600 n e 2 X G e d S i k r a D LZ 10 � 46 10 � 10 10 � 47 10 � 11 G I N R E T T A C Atmospheric and DSNB Neutrinos T S 10 � 48 RE N 10 � 12 H E O C O I N R U T E N 10 � 49 10 � 13 10 � 50 10 � 14 1 10 100 1000 10 4 WIMP Mass � GeV � c 2 � • Limited at low mass by detector threshold • Limited at high mass by density • Eventually limited by neutrinos
So where are we? (LZ edition) Ge, NaI no discrimination C. Amole et al ., arXiv:1702.07666 Ge, w/discrim. C. Amole et al ., arXiv:1702.07666 CDMS w ZEPLIN-III Darkside SCDMS LXe, w/discrim. DEAP LUX XENON 1T LZ <3×10 -48 cm 2 (XENON nT) 3
annihilation cross section �� collider f < σ v > ann ≈ 3 × 10 − 26 cm 3 sec − 1 time � α 2 ≈ � (200GeV) 2 ? direct � Coupling e.g. to light time quarks �� f time ⌅ Indirect ⌅ Z ⇒ G 2 f µ 2 ∼ 10 − 39 cm 2 ⇤ 0 ≈ 2 ⇥
Z-exchange ⌅ excluded SuperCDMS Soudan Low Threshold ⌅ XENON 10 S2 (2013) 10 � 39 CDMS-II Ge Low Threshold (2011) 10 � 3 PICO250-C3F8 CDMSlite Z CoGeNT (2012) 10 � 40 10 � 4 (2013) CDMS Si (2013) SIMPLE (2012) 10 � 41 10 � 5 WIMP � nucleon cross section � cm 2 � COUPP (2012) WIMP � nucleon cross section � pb � DAMA ) 2 1 0 2 ( I I I - N I 10 � 42 CRESST L 10 � 6 CDMS II Ge (2009) P E Z S u Xenon100 (2012) p e EDELWEISS (2011) r C 10 � 43 D 10 � 7 M S S N ) N O 3 L 1 A B 0 n 2 a EU d ( u X o U 0 S L 5 T S e M d 10 � 44 R 10 � 8 i D S C k I r r a N e 3 I p D u F O S C - 0 7 Be 5 C y T 2 C A T E a O OH d T S - C 0 E R I 0 P R N E 3 X B Neutrinos I N A U L 8 B L O 10 � 45 10 � 9 N G S T S 1 M n o D Neutrinos 0 n C 0 e 2 6 r X e G 3 p P u e A S d E i D S k r a D LZ 10 � 46 10 � 10 10 � 47 10 � 11 C AT TERI N G T S s 10 � 48 N o 10 � 12 R E n i r t H E u e N O C B N O S I N D R U T d N E n a c i r e h p s 10 � 49 o 10 � 13 m t A 10 � 50 10 � 14 1 10 100 1000 10 4 WIMP Mass � GeV � c 2 �
annihilation cross section �� collider f < σ v > ann ≈ 3 × 10 − 26 cm 3 sec − 1 time � α 2 � ≈ (200GeV) 2 ? direct � Coupling proportional to time HIGGS MEDIATED mass (e.g. via higgs) �� f time ⌅ Indirect ⌅ h 1 m p g ∼ 1 ⇒ y p ∼ few v ⇤ 0 ∼ 10 − 39 cm 2 × 10 − 6 ∼ 10 − 45 cm 2
Z-exchange ⌅ excluded SuperCDMS Soudan Low Threshold ⌅ XENON 10 S2 (2013) 10 � 39 CDMS-II Ge Low Threshold (2011) 10 � 3 PICO250-C3F8 CDMSlite CoGeNT Z (2012) 10 � 40 10 � 4 (2013) CDMS Si (2013) SIMPLE (2012) 10 � 41 10 � 5 WIMP � nucleon cross section � cm 2 � COUPP (2012) WIMP � nucleon cross section � pb � DAMA ) 2 1 0 2 ( I I I - N I 10 � 42 CRESST L 10 � 6 CDMS II Ge (2009) P HIGGS MEDIATED E Z S u p Xenon100 (2012) e EDELWEISS (2011) r C 10 � 43 D 10 � 7 M S S N ) N O 3 L 1 A B n 0 a 2 EU d ( Higgs exchange ⌅ u X o U 0 S L 5 T S e M d 10 � 44 R 10 � 8 D i S C k I r r e a I N 3 p D F u C O S - 0 5 7 Be C y 2 T C A T E a O OH d C T S - 0 E R I 0 P R N E 3 X B Neutrinos ⌅ I N U A 8 B L L O 10 � 45 10 � 9 N G S T S 1 M n o Neutrinos D 0 n C 0 e r 2 6 X e G 3 p h P u e A S d E S i D k r a D LZ 10 � 46 10 � 10 10 � 47 10 � 11 C AT TERI N G T S s o 10 � 48 N 10 � 12 n R E i r t H E u e N O C B N O S I N D R U T d N E n a c i r e h p s 10 � 49 o 10 � 13 m t A 10 � 50 10 � 14 1 10 100 1000 10 4 WIMP Mass � GeV � c 2 � “This era will answer the question: does the dark matter couple at O(0.1) to the Higgs boson” N. Weiner, CIPANP 2015
The case for dark matter ,*&31)#$,";?(1?$ • We know it interacts co A sam pling of gravitationally available dark matter candidates co It’s • It is “dark” - should not d probably interact with light or electromagnetism WIMPs, right? • Nearly collision less • Slow must be composite must be bosonic m P l ∼ 10 − 20 eV ∼ 100 M � ∼ 10 19 GeV ∼ 100 eV m DM 8
42 − 10 Low Mass Dark Matter (<10 GeV) LZ sensitivity (1000 live days) LUX (2017) Projected limit (90% CL one-sided) XENON1T (2017) 43 − ] 10 2 1 expected ± σ SI WIMP-nucleon cross section [cm PandaX-II (2017) +2 expected σ 44 − 10 45 − 10 pMSSM11 (MasterCode, 2017) 46 − 10 47 − 10 1 neutrino event NS) 48 − ν Neutrino discovery limit (CE 10 − 49 10 10 100 1000 2 WIMP mass [GeV/c ] 9
�� - �� �� � ���� ������ - ������� σ �� [ �� � ] ���� ������ - ������� σ �� [ �� ] �� - �� �� � �� - �� �� - � �� - �� �� - � NEWS-G �� - �� �� - � �� - �� �� - � Much less CRESST-II �� - �� �� - � constrained! CDMSLite �� - �� �� - � 42 DS-50 − 10 S2-only LZ sensitivity (1000 live days) LUX (2017) �� - �� �� - � Projected limit (90% CL one-sided) XENON1T (2017) 43 − ] 10 2 1 expected ± σ SI WIMP-nucleon cross section [cm PandaX-II (2017) +2 expected σ �� - �� �� - � 44 − 10 Fake neutrino floor �� - �� 45 − 10 ���� ���� ���� � � �� �� pMSSM11 (MasterCode, 2017) 46 − 10 ���� ������ ���� [ ��� / � � ] 47 − 10 1 neutrino event NS) 48 − ν Neutrino discovery limit (CE 10 49 − 10 10 100 1000 2 WIMP mass [GeV/c ] 10
DM Prognosis? DM Prognosis? Bad news: DM-SM interactions are not obligatory If nature is unkind, we may never know the right scale must be composite must be bosonic m P l ∼ 10 − 20 eV ∼ 100 M � ∼ 10 19 GeV ∼ 100 eV m DM Good news: most discoverable DM candidates are in thermal equilibrium with us in the early universe Why is this good news? 11 Courtesy G. Krnjaic
DM Prognosis? DM Prognosis? Bad news: DM-SM interactions are not obligatory If nature is unkind, we may never know the right scale must be composite must be bosonic m P l ∼ 10 − 20 eV ∼ 100 M � ∼ 10 19 GeV ∼ 100 eV m DM Good news: most discoverable DM candidates are in thermal equilibrium with us in the early universe Why is this good news? 12 Courtesy G. Krnjaic
Thermal dark matter • “Most discoverable DM candidates are in thermal equilibrium” - G. Krnjaic • If we can detect it, it’s likely that it was in equilibrium (e.g. interacted enough) • Thermal dark matter has minimum annihilation rate (to set relic density) • Doesn’t care about initial conditions (washed out by thermal bath) - makes modeling easier • Limited viable mass range (to a range that is basically within reach) m DM nonthermal nonthermal ∼ 10 − 20 eV ∼ 100 M � m P l ∼ 10 19 GeV < 10 keV < MeV > 100 TeV GeV m Z MeV { too much { too hot Neff / BBN “WIMPs” Light DM 13 Direct Detection (Alan Robinson)
Thermal dark matter m DM nonthermal nonthermal ∼ 10 − 20 eV ∼ 100 M � m P l ∼ 10 19 GeV < 10 keV > 100 TeV < MeV GeV m Z MeV { too much { too hot Neff / BBN Light DM “WIMPs” Direct Detection (Alan Robinson) LZ, LAr, PICO, LHC, etc Wide open Mature >5 GeV program 18 14
Are there actual candidates? • Annihilation cross section needed for the relic abundance annihilation cross section < σ v > ann ≈ 3 × 10 − 26 cm 3 sec − 1 • New weak scale particle has to be heavier than ~a few GeV • Lee and Weinberg, PRL 39 (1977) 165-168 χ f σ v ∼ α 2 m 2 ∼ 10 − 29 cm 3 s − 1 ⇣ m χ ⌘ 2 W, Z χ m 4 GeV Z χ f 15
Are there actual candidates? • Light dark matter needs new forces (although we might already be there in canonical WIMP dark matter anyway) • Asymmetric DM US Cosmic Visions: New Ideas in Dark Matter 2017 : • Secluded DM Community Report • Forbidden DM Yes! • SIMP • ELDER • Freeze in models 1707.04591 16
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