The Disastrous Situation… Experiments over the last year have verified our standard model, and confirmed the earlier indirect indications of no new physics to better than 5 sigma
The Disastrous Situation… just terrible…!
The String Soundscape …or, what gravity wave detectors can tell us about BSM physics John March-Russell Oxford University Isabel Garcia Garcia, Sven Krippendorf, JMR — arXiv:1607.06813
Gravitational Waves • GW have been directly observed by LIGO, and many new detectors will be built • The astrophysical potential Black�Holes Neutron�stars of GW detectors has been pulsars extensively studied supernovae e.g. see Lasky et al. arXiv:1511.05994 • Can we use GW experiments to learn about BSM?
GW detectors for BSM There are a few examples: • Inflation • Strong 1st order EW (& QCD) phase perfect�for�eLISA� transitions (if�they�existed!) Review: Caprini et al. arXiv:1512.06239 • Probing the existence of a QCD axion due to BH super-radiance with�aLIGO Arvanitaki et al. arXiv: 1411.2263 & 1604.03958
GW detectors for BSM There are a few examples: • Inflation • Strong 1st order EW (& QCD) phase perfect�for�eLISA� transitions (if�they�existed!) Review: Caprini et al. arXiv:1512.06239 • Probing the existence of a QCD axion due to BH super-radiance with�aLIGO +�GW�signals�from�vacuum�decay�in� Arvanitaki et al. arXiv: String�Theory�motivated�scenarios 1411.2263 & 1604.03958
Since here in Trieste the seafood is so good I'm sure that you'll vividly be able to picture the type-IIB string flux compactification landscape
the string polyfaucibus D-branes for moduli stabilisation warped unwarped KS throat H 3 D3 D3 Standard Model F 3
String Flux Compactifications A typical stringy set-up: a�lot�of�highly�warped� (the�6�compactified� regions:�throats� dimensions) (think�RS!) SM�??? many�hidden� sectors!
String Flux Compactifications Throats are due to back-reaction from fluxes (need many pairs of integer fluxes K, M for the landscape) �warp�factor�at�throat� tip
String Flux Compactifications a�lot�of�these�throats�have� anti-D3�branes�(it�is�a�severe� restriction�otherwise)
String Flux Compactifications these�p�anti-D3's�lead�to�either�a� classically�unstable�configuration� or�a�metastable�one�
String Flux Compactifications A typical throat features a metastable, SUSY-breaking, false vacuum, as well as a true (locally) SUSY-preserving one Kachru, Pearson, Verlinde: hep-th/0112197 physics�described�by�effective� angular�scalar�field V eff ( ψ ) false� vacuum true�vacuum ρ vac ψ ψ fv π
String Flux Compactifications leading�effective� Lagrangian V eff ( ψ ) false� vacuum true�vacuum ρ vac ψ ψ fv π
String Flux Compactifications non-standard�DBI-like�kinetic�terms�(makes�a�difference� to�critical�bubble�profile,�and�later�evolution) (here�I've�set�M str =1�and�am�working�in�red-shifted�units�so�tip� warp�factor�w IR �is�hidden)
String Flux Compactifications as�ratio�p/M=r�reaches�a�critical�value �barrier�disappears,�so�define
String Flux Compactifications as����������false�vacuum�decay�becomes�fast δ → 0 V eff ( ψ ) GW�from� false� vacuum�decay vacuum true�vacuum ρ vac ψ ψ fv π
String Flux Compactifications For this talk some simplifying assumptions: • After inflation , throat in its metastable vacuum • Visible sector reheated at but T rh & 4 MeV hidden throat sector left at T th ≈ 0 so�decay�occurs�via�quantum�tunnelling • Universe radiation dominated throughout (may�be�relaxed�to�include�a�phase�of�matter�domination) ρ vac ρ total ( T ) = ρ rad ( T ) + ρ vac with α ( T ) ≡ ρ rad ( T ) ≤ 1
Vacuum decay Bubbles�of�the�true�vacuum�are� nucleated�in�the�early�Universe Bubbles�form expand collide! … … The�Universe� is�in�a� new�phase They�quickly�start� Bubbles�collide,�emitting� expanding�at�the� gravity�waves�(and�maybe� speed�of�light forming�some�pBHs�too…)
Vacuum decay T vis Nucleation probability increases as T vis falls false� decay�rate�per�unit� Γ vacuum! volume�(T�independent) ∼ H ( T ) 4 decreases�as�the T n temperature�drops true� vacuum! Γ when the transition starts H ( T n ) 4 ≈ 1 T ∼ 1 MeV
Vacuum decay Nucleation probability given by Coleman's bounce solution We find for our system always a thick-walled bounce
Vacuum decay Nucleation probability given by Coleman's bounce solution We find for our system always a thick-walled bounce
Gravity Wave Spectrum Putting everything together we find a stochastic gravity wave spectrum with approximate peak frequency visible�temperature� at�bubble�collision duration�of�transition� in�Hubble�times
Gravity Wave Spectrum Putting everything together we find a stochastic gravity wave spectrum with approximate peak frequency visible�temperature� at�bubble�collision duration�of�transition� in�Hubble�times nucleation�temperature�T n �is�exponentially�sensitive�to� underlying�throat�parameters�so�f 0� scans
GW peak frequency 10 7 10 14 d= 10 - 3 10 4 10 11 V = 10 2 10 10 8 V = 10 10 V = 10 18 10 - 2 10 5 f 0 T c Hz GeV 10 - 5 10 2 10 - 8 10 - 1 d= 10 - 2 10 - 11 10 - 4 10 - 15 10 - 12 10 - 9 10 - 6 10 - 3 w IR (here�have�fixed�M=10 2� and�g s =0.03)
GW peak frequency 10 7 10 14 d= 10 - 3 10 4 10 11 V = 10 2 10 10 8 V = 10 10 V = 10 18 10 - 2 10 5 f 0 T c Hz GeV 10 - 5 10 2 10 - 8 10 - 1 d= 10 - 2 10 - 11 10 - 4 10 - 15 10 - 12 10 - 9 10 - 6 10 - 3 w IR warp�factor�at�the� tip�of�the�throat
GW peak frequency 10 7 10 14 d= 10 - 3 10 4 10 11 V = 10 2 10 10 8 V = 10 10 V = 10 18 10 - 2 10 5 f 0 T c Hz GeV 10 - 5 10 2 decreasing δ 10 - 8 10 - 1 d= 10 - 2 10 - 11 10 - 4 10 - 15 10 - 12 10 - 9 10 - 6 10 - 3 w IR
GW peak frequency 10 7 10 14 d= 10 - 3 10 4 10 11 V = 10 2 volume�of�compactification� 10 10 8 V = 10 10 increasing� V = 10 18 10 - 2 10 5 f 0 T c Hz GeV 10 - 5 10 2 10 - 8 10 - 1 d= 10 - 2 10 - 11 10 - 4 10 - 15 10 - 12 10 - 9 10 - 6 10 - 3 w IR
GW peak frequency 10 7 10 14 d= 10 - 3 10 4 10 11 V = 10 2 10 10 8 V = 10 10 V = 10 18 10 - 2 10 5 f 0 T c Hz GeV 10 - 5 10 2 10 - 8 10 - 1 d= 10 - 2 10 - 11 10 - 4 10 - 15 10 - 12 10 - 9 10 - 6 10 - 3 w IR The�frequency�can�span�the�entire�range�being/to-be�probed� by�gravity-wave�detectors
GW peak frequency 10 7 10 14 d= 10 - 3 10 4 10 11 V = 10 2 10 10 8 V = 10 10 V = 10 18 10 - 2 10 5 f 0 T c Hz GeV 10 - 5 10 2 10 - 8 10 - 1 d= 10 - 2 10 - 11 10 - 4 10 - 15 10 - 12 10 - 9 10 - 6 10 - 3 w IR requires�that�at�least�one�of�the�many�throats�in�a�typical� flux�compactification�has����in�suitable�range δ
GW peak frequency 10 7 10 14 d= 10 - 3 10 4 10 11 V = 10 2 10 10 8 V = 10 10 V = 10 18 10 - 2 10 5 f 0 T c Hz GeV 10 - 5 10 2 10 - 8 10 - 1 d= 10 - 2 not�guaranteed�of�course� 10 - 11 10 - 4 but�not�unreasonable�either� 10 - 15 10 - 12 10 - 9 10 - 6 10 - 3 w IR requires�that�at�least�one�of�the�many�throats�in�a�typical� flux�compactification�has����in�suitable�range δ
GW signal strength Signal�strength�is�large�due�to: •long�duration�of�transition�(nucleation�rate�does�not� increase�with�falling�T�unlike�thermal�case)� •ultra-relativistic�expansion�of�bubbles�(no�thermal� plasma�to�impede�expansion)��
GW signal strength 10 - 3 EPTA aLIGO SKA 10 - 6 false�vacuum�energy� eLISA a c = 10 - 1 decreasing� 10 - 9 Ω GW h 2 ρ vac a c = 10 - 2 LISA α c ≡ ρ rad ( T c ) a c = 10 - 3 10 - 12 BBO 10 - 15 10 - 7 10 - 10 10 - 4 10 - 1 10 2 10 5 f 0 / Hz
GW signal strength 10 - 3 EPTA aLIGO SKA NOT�the�actual�high- 10 - 6 eLISA frequency�behaviour�of� a c = 10 - 1 spectrum�-�just�the� 10 - 9 Ω GW h 2 usual�one�for�guidance� a c = 10 - 2 LISA a c = 10 - 3 10 - 12 BBO 10 - 15 10 - 7 10 - 10 10 - 4 10 - 1 10 2 10 5 f 0 / Hz
GW signal strength 10 - 3 Different�because� EPTA aLIGO SKA • �����has�unusual�T-dep� Γ /H 4 10 - 6 •Bubbles�are�thick-wall� eLISA a c = 10 - 1 •DBI�kinetic-term�leads� to�new�features� 10 - 9 Ω GW h 2 a c = 10 - 2 LISA (work�in�progress) a c = 10 - 3 10 - 12 BBO 10 - 15 10 - 7 10 - 10 10 - 4 10 - 1 10 2 10 5 f 0 / Hz
GW signal strength 10 - 3 EPTA aLIGO SKA 10 - 6 eLISA a c = 10 - 1 high-frequency� 10 - 9 Ω GW h 2 a c = 10 - 2 LISA part�of�spectrum� a c = 10 - 3 sensitive�to� 10 - 12 underlying� BBO (string)�model! 10 - 15 10 - 7 10 - 10 10 - 4 10 - 1 10 2 10 5 f 0 / Hz
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