Phase Transitions, Gravitational Waves, and Composite Dark Matter - PowerPoint PPT Presentation

Phase Transitions, Gravitational Waves, and Composite Dark Matter Pedro Schwaller (DESY) Lattice for BSM Physics 2016 Argonne National Laboratory April 22, 2016

2 Outline • DM from confining SU(N) • First order Phase Transitions • PT dynamics from lattice? • Gravitational Waves from FOPT • Detection - Ground, Space, PTA

3 Composite DM • Alternative to elementary WIMP models • Phenomenologically viable, “generic” possibility in presence of hidden sectors • Some nice features: • DM stability, mass scale • Symmetric component annihilation for ADM • Self-interactions


 4 Dark QCD • Models I’m interested in here • Nonabelian SU(N) dark sector, confinement scale Λ d • light/massless flavours n f n f > 0 n f = 0 Glueball DM 
 Dark Baryons 
 or Dark Pions PT from center symmetry restoration Chiral Symmetry Breaking

The Dark Phase Transition

6 Phase Transition • SU(N) dark sectors well motivated • Confinement/chiral symmetry breaking phase transition at scale Λ d ‣ DM: (MeV - 100 TeV) Λ d ∼ M DM ‣ Naturalness: Λ d ∼ few × Λ QCD • First order PT in large class of models • Still possible if LHC finds no new physics

7 QCD Phase Diagram • Strong First Order W e a k C r SM m s o s s - o v e r Strong First Order 0 0 • m u , d

8 Phase Diagram II Glueball DM • Strong First Order W Fraternal e a k C r SM m s o Twin Higgs s s - o v e r Dark QCD SIMP models Strong First Order 0 0 • m u , d

9 SU(N) - PT • Consider with massless flavours SU ( N d ) n f • PT is first order for ‣ , n f = 0 Svetitsky, Yaffe, 1982 N d ≥ 3 M. Panero, 2009 ‣ , 3 ≤ n f < 4 N d N d ≥ 3 Pisarski, Wilczek, 1983 • Not for: ‣ (no global symmetry, no PT) n f = 1 ‣ (not yet known) n f = 2

10 SU(N) - PT 2 • One more parameter: angle Θ • Effect on PT not well studied M. Anber, 2013 Garcia-Garcia, Lasenby, March-Russell, 2015 • dependence of PT strength? N d , n f Panero, 2009 • Finite density/chemical potentials? 10 0 19 ‣ QCD FOPT? Current NANOGrav sensitivity 22 PTA 2020 10 4 0.01 1 100 10 4 Schwarz, Stuke, 2009 10 − 5 h 2 Ω (f) ‣ GW signal: LISA Caprini, Durrer, Siemens, 2009 10 − 10 10 − 15 10 − 10 10 − 8 10 − 6 10 − 4 10 − 2 f [Hz]

11 Questions for Lattice • Dynamics of PT known from lattice? • Latent heat • Bubble nucleation rate I’d be happy to collaborate! • Dependence on N d , n f • theta param, chem. potentials? • At least some of this is known AFAIK • For Cosmology: relevant T < T C

Gravitational Wave spectra from FOPT

13 Cosmological Phase Transitions • Early Universe in symmetric phase (e.g. unbroken electroweak symmetry) T > T c T < T c T < T c Second 
 First 
 order order

14 GWs from PTs First order PT ➞ Bubbles nucleate, expand Bubble collisions ➞ Gravitational Waves

15 Signal is Universal • PT characterised by few parameters: α ≈ Ω vacuum • Latent heat 
 Extensive numerical Ω rad simulations. Recently e.g. Hindmarsh et al: • Bubble wall velocity v Sound wave contributions β • Bubble nucleation rate T ∗ • PT temperature • Three physical contributions • Bubble wall collisions Phenomenological • Turbulence Parameterisations: • Sound waves Caprini et al, 1512.06239

16 GW signal Bubble Collisions Turbulence 10 - 6 r e l l a m s y l b a b o r p * 10 - 8 h 2 Ω GW 10 - 10 10 - 12 10 - 8 10 - 7 10 - 6 10 - 5 10 - 4 0.001 0.010 f [ Hz ]

17 Peak Frequency • Redshift: ⇣ g ∗ ⌘ 1 ✓ ◆ f = a ∗ f ∗ T ∗ ⇥ f ∗ = 1 . 59 ⇥ 10 − 7 Hz ⇥ 6 ⇥ H ∗ a 0 H ∗ 80 1 GeV H ∗ PT Temperature q ~ DM Mass • Peak regions: k/ β ≈ (1 − 10) H ◆ ✓ β ⇣ g ∗ ⌘ 1 ✓ ◆ T ∗ peak = 3 . 33 ⇥ 10 − 8 Hz ⇥ f ( B ) 6 80 1 GeV H ∗

18 Experiments Satellite based NANOGrav 10 - 1 eLISA: 2028/2032 Ground based eLISA old 10 - 4 EPTA SKA LIGO 2016 10 - 7 Ω GW h 2 LIGO 2022 IPTA 10 - 10 * eLISA best case BBO 10 - 13 10 - 9 10 - 7 10 - 5 0.001 0.100 10 f [ Hz ] Pulsar timing arrays Data already available * From A. Petiteau

19 Composite ADM Composite B-L DM SIMP breaking, Twin Higgs WIMP-y Unitarity Hidden Sectors 0.001 EPTA 10 - 5 SKA IPTA ELISA 10 - 7 ALIA LIGO h 2 W GW LISA 10 - 9 T * = 0.1 GeV 10 - 11 V T * = 300 GeV e DECIGO G 3 T * = 10 TeV 10 - 13 = T * BBO 10 - 15 0.01 1 10 - 10 10 - 8 10 - 6 10 - 4 f @ Hz D

20 Summary • Symmetry breaking with first order PT ➞ 
 Gravitational Waves! • Signal from composite DM sector could be observable • Interesting tasks for numerical (lattice) simulations • PT dynamics for strongly coupled models • PT non-perturbative sometimes even for weakly coupled models • Simulation of GW signal from PT

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22 GWs as window to dark matter sector • Motivation for (non-abelian) Dark Sectors • Phase Transition of SU(N) Theories • GW Signals from PTRs to ELISA Based on PRL 115 (2015) 18, 181101

23 Dark Matter We#have#seen#DM#in#the#sky:# But#no#direct#observa7on## LUX# − 44 10 6 8 10 12 − 40 10 − 45 10 − 42 10 − 44 10 1 2 3 10 10 10 m WIMP (GeV/c 2 ) Maybe#DM#is#just#part#of#a#larger#dark#sector## • Example:#Proton#is#massive,#stable,#composite#state# • DM#self#interac7ons#solve#structure#forma7on#problems# • New#signals,#new#search#strategies!#

24 Composite DM • SU(N) dark sector QCD dark QCD with neutral 
 X d “dark quarks” TeV • Confinement scale asymmetry Λ darkQCD sharing p D , . . . • DM is composite annihilation “dark proton” π D , . . . GeV p , n decay Bai, PS, PRD 89, 2014 π , K , . . . PS, Stolarski, Weiler, JHEP 2015 many other works! Similar setup e.g.: Blennow et al; Cohen et al; Frandsen et al; Reviews: Petraki & Volkas, 2013; Zurek, 2013;

25 DM Motivation • New mechanisms for relic density, extend mass range: ‣ Asymmetric DM - GeV-TeV scale ‣ Strong Annihilation - 100 TeV scale ‣ SIMP - MeV scale Hochberg, Kuflik, Volansky, Wacker, 2014; + Murayama, 2015 • Advantages of Composite ‣ DM mass scale and stability ‣ Fast annihilation for ADM ‣ Self-interactions for structure formation

26 GW spectra • Lot of work on GW from 1st order PT See talks by Hindmarsh, Weir • Still difficult to simulate or model for more details • Here in addition: • Transition is non-perturbative • Parameters not known - take an optimistic guess β /H ∗ = 1 − 100 v = 1 κα 1 + α = 0 . 1