Ian Shoemaker. Santa Fe Summer Workshop - INFO 2011 July 20, with Michael Graesser and Luca Vecchi

Transcription

1 Ian Shoemaker Santa Fe Summer Workshop - INFO 2011 July 20, 2011 with Michael Graesser and Luca Vecchi 1

2 Dark matter à la Occam lex parsimoniae Visible sector Dark sector χ 2 2

3 The WIMP miracle χχ ff =? Ω DM h 2 = 0.1 ( cm 3 s 1 σv ) 3 3

4 What do we really know about DM? 1. Cosmological abundance. 2. It s stable (or at least very long-lived). 4 4

5 [Larson, et al. (2010)] Clue #1: WMAP The amounts of dark and visible matter are comparable. WMAP 7 tells us: Ω DM h 2 = ± Ω B h 2 = DMB ratio: Ω DM Ω B 5 This could be 1. A remarkable coincidence. 2. An anthropic selection effect? [Freivogel (2008)] 3. An indication of an underlying origin. 5

6 Enter asymmetric dark matter Maybe DM carries an particle anti-particle asymmetry like baryons. Earliest attempts made use of EW sphalerons (Nussinov 1985; Barr, Chivukula, Farhi 1990; Kaplan 1992). Modern incarnation makes use of higher dimensional operators to transfer the asymmetry (Kaplan, Luty, Zurek 2009). ADM models prefer GeV scale masses, but can accommodate weak scale masses (Buckley, Randall 2010), or sub-gev masses (Falkowski, Ruderman, Volansky 2011). 6 6

7 Will the real model of nature please stand up? Darkogenesis? [J. Shelton, K. Zurek (2010)] Xogensis? [M. Buckley, L. Randall (2010)] Aidnogenesis? [Blennow, et al. (2010)] Hylogenesis? [H. Davoudiasal et al. (2010)] Cladogenesis? [R. Allahverdi, B. Dutta, K. Sinha (2011)] Pangenesis. [N. Bell, K. Petraki, I.M.S., R. Volkas (2011)] 7 7

8 Will the real model of nature please stand up? Darkogenesis? [J. Shelton, K. Zurek (2010)] Xogensis? [M. Buckley, L. Randall (2010)] Aidnogenesis? [Blennow, et al. (2010)] Hylogenesis? [H. Davoudiasal et al. (2010)] Cladogenesis? [R. Allahverdi, B. Dutta, K. Sinha (2011)] Pangenesis. [N. Bell, K. Petraki, I.M.S., R. Volkas (2011)] 8 8

9 BSM physics has a love/hate relationship with the proton Often predict an intriguing signal... For example, in SU(5): The only problem is

10 Super Kamiokande says: The proton is stable. 10

11 The proton is stable Why? L = L SM + L eff L eff QQQL Λ 2 Baryon number is an unreasonably good symmetry p e + π 0 τ p > yr Λ > GeV! 11 11

12 Think globally? Act locally. Promote U(1)B to a local gauge symmetry. New quarks to cancel anomalies. To avoid stable colored particles, introduce new particle X, to facilitate decay. X is automatically stable. Baryogenesis requires a DM asymmetry. Shared gauge interactions with baryons may facilitate its discovery

13 Gauging baryon number Ancient examples: Carone and Murayama 1998; Bailey and Davidson 1995; Aranda and Carone More recently: Dulaney, Fileviez-Perez and Wise (2010); Buckley, Fileviez-Perez, Hooper, and Neil (2011)

14 An anomaly-free model New chiral states N dark generations Spontaneously break U(1) B 14 14

15 Not your typical 4th generation Gauge symmetry forbids mass mixing. No tree-level flavor changing processes, decay modes not like conventional 4th gen. New quarks carry their own global U(1) Bq The lightest particle in Q -sector will be stable

16 Absence of stable colored particles Exotic quarks must decay... L u cd c d cx Λ q qqx Turning off gauged baryon number, we see three accidental symmetries Q e iθ q Q Q e iθ q Q S e iθ S S gauge B = B = B q + B q + B S 16 16

17 Absence of stable colored particles Exotic quarks must decay... ( X ± 1, 1, 0, ± ( 2 )) Introduce: 3 1 N L u cd c d cx Λ q qqx Decay operator asymmetry transfer operator 17 17

18 Spontaneous breaking B = B q + B q + B S U(1) B S B 0 U(1) Bq U(1) Bq proton stability DM stability 18 18

19 STABILITY OF MATTER What about proton/dm decay at the nonrenormalizable level? O bad XP δ S ɛ L ν O X δp + ɛs + νl + O worse pl α X β S γ O p αl + βx + γs + Simple example: m X > m p Proton stability: B(S) Z, B(S) > 1 DM stability: B(X) = fraction

20 Baryogenesis implies a DM asymmetry The only global symmetry is a non-anomalous U(1)D: D = B q + B q n B n B n X n X Unlike conventional ADM, the asymmetries are co-generated. Recent work by: Bell, Petraki, IMS, Volkas [ ]; Cheung and Zurek [ ]

21 Asymmetries are generic CP violation. A. Sakharov U(1) violation; gravity doesn t respect them. Out of equilibrium

22 Super example: Affleck-Dine Affleck-Dine simplified: n B = θ φ 2 Acquire a large VEV. Kick the field in the phase direction. Affleck, Dine (1985); Dine, Randall, Thomas (1995)

23 Symmetries chemical potentials Harvey & Turner (1992) Universe is EM neutral. EW Sphalerons are active above T EW. Transfer operator W and Higgs exchange. Solve for: µ u, µ d, µ l, µ ν, µ W, µ X, µ q 23 23

24 Similar asymmetries yield similar masses Generically: η B η X = O(1) For the model introduced above: η B η X 6 m X m p ( n+ n n + + n ) = η B η X Ω DM Ω B m X 30 GeV Light DM is generic in ADM models

25 Abundance via annihilation Minimal assumption: X q annihilation dominantly Z B from s-channel ZB X q σ ann v = f N c 2π m2 X N f 3π m2 X ( g 2 B m 2 B ( q X g 2 B m 2 B q X 3 ) 2 (2 + m2 f ( 1 4m2 X m 2 B ) 2 [ ( 1 4m2 X m 2 B m 2 X ) ) 2 + Γ 2 B m 2 B ) 2 + Γ2 B m 2 B ] 1 1 m2 f m 2 X 25

26 Asymmetry impact on abundance from M. Graesser, I.MS., L. Vecchi, arxiv:1103:2771 XX ff As long as an asymmetry exists prior to FO, must solve coupled Boltzmann eqs. for abundances. Large σv Small σv Ω DM η Ω DM σv 1 More generally: Ω DM = f(η, σv, m) σv cm 3 s 1 ADM can have WIMP sized cross sections! 26

27 DIRECT DETECTION BOUNDS 012''!'*-3425%(-6. /%75216&84'*9%32%5:-8*25; <=!?C <=!?B <=!?A <=!>= <=!>< CRESST (2001) CDMS low threshold (2010) XENON100 (April 2011) <= = <= <!"#$%#&''%()*+,-. / 27

28 RECOIL SPECTRUM dr de R = N T ρ m X astrophysics/n-body d 3 v vf( v, v ) dσ v >v de min R kinematics particle physics Velocity distribution must be consistent with NFW: f(v) [ exp ( v 2 esc v 2 kv 2 0 ) ] k [Lisanti, Strigari, Wacker, 1 Wechsler (2010)] Non-trivial velocity/momentum dependence in cross section in some models. 28

29 RECOIL SPECTRUM VECTOR CASE: D µ X = µ ( 0 X + ig B qv + q A γ 5) Z µ B X dσ = m NA 2 de R 2πv 2 ( qv g 2 B m 2 B ) 2 F 2 (E R ) DD imposes: m X few GeV AXIAL CASE: D µ X = µ X + ig B ( qv + q A γ 5) Z µ B X 0 dσ = m N A 2 de R 8πv 2 ( qa g 2 B m 2 B ) 2 [ Av 2 + Bq 2] F 2 (E R ) Always 2 below DD bounds. 29

30 BARYONIC DARK FORCES AND COLLIDERS 30

31 A TRIFECTA OF EXPERIMENTS LEP q Z Z B q BaBar: invisible/hadronic upsilon decays. LEP: hadronic width of the Z boson. Tevatron: monojets + missing energy. 31

32 B-FACTORY CONSTRAINTS If m X m Υ /2, the upsilon can decay to DM. Υ(1S) Z B XX BaBar constrains: BR(Υ(1S) invisible ) < BR(Υ(1S) invisible ) BR(Υ(1S) µ + µ ) = ( qv 2 + qa 2 ) [ gb 2 e 2 m 2 Υ m 2 B m2 Υ ] 2 <

33 BOUNDING A BARYONIC GAUGE BOSON WITH LEPTONS q Kinetic mixing: Z Z B L kin = 1 4 (Zµν B Zµν B 2c Zs W Z µν B Zµν + 2c γ c W Z µν B Aµν ) q Γ had Γ had g B 4π c Z (m Z ) m 2 Z m 2 Z m2 B ±

34 Experimental constraints: LEP + B-factories m X m Υ /2 0.6 invisible upsilon width decay Z hadronic width m X m Υ /2 hadronic upsilon width g B m B GeV 34

35 Monojets at the Tevatron 1fb 1 analyzed data E T > 80 GeV p T (j 1 ) > 80 GeV p T (j 2 ) < 30 GeV p T (j 3 ) < 20 GeV pp E T + j 8449 events seen See also: Bai, Fox, and Harnik (2010); Goodman et al. (2010) 35 35

36 DARK FORCES AT THE TEVATRON D µ X = µ ( 0 X + ig B qv + q A γ 5) Z µ B X 8449 events w/ 1fb -1 SM: 8662 ± C.L. S < 330 events L = 1 fb GeV -Madgraph/Madevent to simulate parton-level signal. g B m X 1 GeV 5 GeV 0.1 -Pythia for ISR/FSR/ hadronization and analysis B 36

37 DARK FORCES AT THE TEVATRON 8449 events w/ 1fb -1 SM: 8662 ± C.L. S < 330 events L = 10 fb 1 Tevatron projection -Madgraph/Madevent to simulate parton-level signal. g B m X 1 GeV 5 GeV 10 GeV 0.1 -Pythia for ISR/FSR/ hadronization and analysis B 37

38 DARK FORCES AT THE TEVATRON off-shell ZB production σ g 4 B on-shell ZB production σ g 2 B 0.7 g B GeV 10 GeV g B Tevatron 0.2 m X 1 GeV 0.04 Tevatron projection B m B GeV 38

39 Combined constraints: vector case D µ X = µ ( 0 X + ig B qv + q A γ 5) Z µ B X g B 0.06 Tevatron decay m DM = 1 GeV 0.04 DM h Tevatron proj m B GeV 39

40 Combined constraints: axial case D µ X = µ ( 0 X + ig B qv + q A γ 5) Z µ B X g B decay Tevatron m DM = 10 GeV DM h m B GeV 40

41 CONCLUSIONS Gauged baryon number saves the proton + automatic DM candidate. Co-generation of dark and visible asymmetries via Affleck- Dine. Consistent with bounds from B-factories, LEP, mono-jet Tevatron searches, and direct detection for: GeV-scale DM with a GeV-scale mediator. 41