Neutrons!and Precision Tests of Supersymmetry

Sean Tulin  (TRIUMF)

The Standard ModelThe Standard ModelA A beautifulbeautiful theory that explains almost all of particle physics with theory that explains almost all of particle physics with only about 20 parameters.only about 20 parameters.

+

y py p

BUT…BUT…

1.1. Why 20 parameters?Why 20 parameters?

Dark Dark

2.2. Doesn’t explain Doesn’t explain observed cosmologyobserved cosmology

Dark Dark energyenergy

mattermatterMatterMatter

3. Hierarchy problem: why M3. Hierarchy problem: why MEWEW << << MMPlanckPlanck ??

Physical Higgs Physical Higgs y ggy ggboson mass:boson mass:

TreeTree--level level parameterparameter OneOne--looploop

Supersymmetry is super!Supersymmetry is super!The minimal The minimal supersymmetricsupersymmetric standard model (MSSM):standard model (MSSM):

+ +

Coupling unificationCoupling unificationHierarchy problemHierarchy problem

Dark Dark and visible matterand visible matter Stringy motivationStringy motivation

Outline:Outline:

1 Beta‐decay correlation coefficients1. Beta decay correlation coefficients

OneOne--loop SUSY contributions lead to fourloop SUSY contributions lead to four--ff l h (l h ( ) () ( ))fermionfermion couplings that are not (Vcouplings that are not (V--A)x(VA)x(V--A).A).

How do SUSYHow do SUSY--induced contributions manifest in induced contributions manifest in the betathe beta decay spectrum?decay spectrum?the betathe beta--decay spectrum?decay spectrum?

How large can they be?How large can they be?

Outline:Outline:

2 Baryogenesis and Electric Dipole Moments2. Baryogenesis and Electric Dipole Moments

b d db d dBaryon asymmetry can be produced in MSSM via Baryon asymmetry can be produced in MSSM via Electroweak Electroweak BaryogenesisBaryogenesis..

Same MSSM CPSame MSSM CP--violating violating phases give rise to both phases give rise to both baryogenesisbaryogenesis and EDMsand EDMsbaryogenesisbaryogenesis and EDMsand EDMs

How do EDMs constrain How do EDMs constrain b ib i ??

PospelovPospelov & Ritz, 2005& Ritz, 2005baryogenesisbaryogenesis??

Beta DecayBeta Decay

Can MSSM impact beta decay of neutron and other nuclei?

Beta‐decayBeta decay

• Correlation coefficients:Correlation coefficients:

Jackson, Jackson, TreimanTreiman, , WyldWyld (1957)(1957),, ,, yy ( )( )

Coefficients Coefficients parametrizeparametrize beta spectrum, can be computed e.g. beta spectrum, can be computed e.g.

In SMIn SM

Also studied by Gardner and Zhang (2000)Also studied by Gardner and Zhang (2000)

Beta‐decayBeta decay

• Beyond the SMBeyond the SMMost general fourMost general four--fermionfermion interaction, with arbitrary coefficientsinteraction, with arbitrary coefficients

Other combinations Other combinations of Dirac matricesof Dirac matrices

SScalarcalar VVectorector TTensorensor

In the SM:In the SM: , and all other parameters vanish., and all other parameters vanish.

In the MSSM:In the MSSM:Goes into Goes into VVudud

KurylovKurylov et al (2002)et al (2002)

Beta‐decayBeta decayCan relate beta decay parameters to nonCan relate beta decay parameters to non--(V(V--A)A)--coefficientscoefficients

SUSY contributionsSUSY contributions

Example of SUSY box graph that Example of SUSY box graph that contributes to betacontributes to beta--decaydecay

LLRR

xx

Consider e.g.Consider e.g.

LL

xx

LLRRRequires LR Requires LR squarksquark and and sleptonslepton mixingmixing

ProfumoProfumo, Ramsey, Ramsey--MusolfMusolf, S.T. (2006), S.T. (2006)

Usually people assumeUsually people assume

And thenAnd then

SUSY contributionsSUSY contributionsFierzFierz interference for interference for supersuper--allowed decaysallowed decayssupersuper--allowed decaysallowed decays

FierzFierz interference for interference for neutron decayneutron decay

(Assuming: real coefficients, (Assuming: real coefficients, VudVud = 1, form factors = 1, form factors gAgA = = gTgT = 1)= 1)

Neutron decay Neutron decay corelationcorelation between n spin and neutrino momentum between n spin and neutrino momentum

Also in MSSM only: we haveAlso in MSSM only: we have

SUSY contributionsSUSY contributionsConsidered large LR mixingConsidered large LR mixing

No reason to prefer large LR mixing, but it is a valid (and often ignored) No reason to prefer large LR mixing, but it is a valid (and often ignored) region of MSSM parameter spaceregion of MSSM parameter space

ProfumoProfumo, Ramsey, Ramsey--MusolfMusolf, S.T. (2006), S.T. (2006)

Experimental boundsExperimental boundsCurrent:Current:

Hardy & Towner (2004)Hardy & Towner (2004)

Agrees with SM. See e.g. Marciano & Agrees with SM. See e.g. Marciano & SirlinSirlin (1993), (1993), CiriglianoCirigliano & & RosellRosell (2007(2007))

Prospective:Prospective:Prospective:Prospective:

See Kevin See Kevin Hickerson’sHickerson’s talktalk

MSSM lives in blue boxMSSM lives in blue box

Fantasy boundsFantasy bounds

Decreasing all Decreasing all Decreasing all Decreasing all experimental experimental limits by order limits by order of magnitudeof magnitude

Implications of large LR‐mixingImplications of large LR mixing

Is there a constraint on LR‐mixing?

Absence of spontaneous Absence of spontaneous breaking of color/EM (along Dbreaking of color/EM (along D--breaking of color/EM (along Dbreaking of color/EM (along Dflat directions) requiresflat directions) requires

f = u, d, ef = u, d, ex3x3

Requires heavy Higgs sectorRequires heavy Higgs sector

Higgs sector reviewHiggs sector review SM: 1 Higgs MSSM: 5 HiggsSM: 1 Higgs MSSM: 5 Higgs

Requires heavy Higgs sectorRequires heavy Higgs sector

ConclusionsConclusions

1. 10‐3 SUSY contributions to beta‐decay correlation1. 10 SUSY contributions to beta decay correlation coefficients possible‐ Requires heavy Higgs sector (still have one light SM‐

like Higgs)

‐ Why?  Why not?

2. If O(10‐3) deviations found, interesting implications for MSSMfor MSSM

Electric Dipole MomentsElectric Dipole Moments 

Implications for baryon asymmetry of the universe

Baryogenesis at Electroweak ScaleBaryogenesis at Electroweak Scale

We want to explainPDG

kl lp

Dunkley et al [WMAP5]

95% C.L.

based on dynamics during the electroweak phase transition.

Timeline of universeTimeline of universe

NucleosynthesisNucleosynthesis

1 min1 minElectroweak scaleElectroweak scale

NowNow

13.7 13.7 GyrGyrRecombinationRecombination

380,000 yr380,000 yr1 min1 min

1010--1010 ss

Era of electroweak symmetry breaking:Era of electroweak symmetry breaking:

Higgs field acquires a vacuum expectation value (Higgs field acquires a vacuum expectation value (vevvev))

Fermions and W,Z bosons get massiveFermions and W,Z bosons get massive

Electroweak Phase TransitionElectroweak Phase Transition

First order electroweak phase transition during the early universe

Higgs potentialHiggs potentialV( )

T > Tc T = Tc

T =0

High T: EW symmetry restored from thermal corrections to Higgs potential

Low T: EW symmetry broken

At critical temp T degenerate minima Just below T quantum At critical temp Tc, degenerate minima. Just below Tc, quantum tunneling from to bubble nucleation!

Electroweak Baryogenesis PictureElectroweak Baryogenesis Picture

Three Steps:Three Steps:

Cohen, Kaplan, Nelson, 1992-1994; Huet, Nelson, 1996

pp

1. Nucleation and expansion of 1. Nucleation and expansion of bubbles of broken EW symmetrybubbles of broken EW symmetry

2 CP2 CP violating interactions at violating interactions at moving bubble 2. CP2. CP--violating interactions at violating interactions at

bubble wall induces charge bubble wall induces charge density, diffusing outside bubbledensity, diffusing outside bubble

3 Sphalerons convert LH 3 Sphalerons convert LH

bubble wall

electroweak

3. Sphalerons convert LH 3. Sphalerons convert LH asymmetry into B asymmetryasymmetry into B asymmetry

diffusionCPCP

y electroweak sphaleron

um

ber

den

sity

Quar

k nu

Electroweak Baryogenesis Picture

Three Steps:Three Steps:

Cohen, Kaplan, Nelson, 1992-1994; Huet, Nelson, 1996

Electroweak Baryogenesis Picture

pp

1. Nucleation and expansion of 1. Nucleation and expansion of bubbles of broken EW symmetrybubbles of broken EW symmetry

2 CP2 CP violating interactions at violating interactions at moving bubble 2. CP2. CP--violating interactions at violating interactions at

bubble wall induces charge bubble wall induces charge density, diffusing outside bubbledensity, diffusing outside bubble

3 Sphalerons convert LH 3 Sphalerons convert LH

bubble wall

4. Baryon asymmetry 4. Baryon asymmetry d b d b bbld b d b bbl

electroweak

3. Sphalerons convert LH 3. Sphalerons convert LH asymmetry into B asymmetryasymmetry into B asymmetry

diffusionCPCP

y

captured by expanding bubblecaptured by expanding bubble

electroweak sphaleron

um

ber

den

sity

Quar

k nu

Electroweak baryogenesis in the d d d lStandard Model

M i f M i f S kh S kh di idi iMust satisfy Must satisfy Sakharov Sakharov conditionsconditions::

1.1. Baryon number Baryon number violation:violation:

P id d b SM P id d b SM l t k l t k h lh lProvided by SM Provided by SM electroweak electroweak sphaleronssphalerons::

-- active in early universe for T > 100 active in early universe for T > 100 GeVGeV

2.2. CC-- and and CPCP--violation: violation:

CKM phase insufficient for CKM phase insufficient for baryogenesisbaryogenesisCKM phase insufficient for CKM phase insufficient for baryogenesisbaryogenesis

3. Departure from thermal equilibrium:3. Departure from thermal equilibrium:

mmhh > 114 > 114 GeVGeV means no firstmeans no first--order phase transitionorder phase transitionhh pp

Electroweak baryogenesis in the Standard Model

M i f M i f S kh S kh di idi iMust satisfy Must satisfy Sakharov Sakharov conditionsconditions::

1.1. Baryon number Baryon number violation:violation:

P id d b SM P id d b SM l t k l t k h lh lProvided by SM Provided by SM electroweak electroweak sphaleronssphalerons::

-- active in early universe for T > 100 active in early universe for T > 100 GeVGeV

2.2. CC-- and and CPCP--violation: violation:

CKM phase insufficient for CKM phase insufficient for baryogenesisbaryogenesis

New CPNew CP--violating violating phases in MSSM!phases in MSSM!

CKM phase insufficient for CKM phase insufficient for baryogenesisbaryogenesis

3. Departure from thermal equilibrium:3. Departure from thermal equilibrium:

mmhh > 114 > 114 GeVGeV means no firstmeans no first--order phase transitionorder phase transitionhh ppFirstFirst--order phase transition in MSSM! (as long as order phase transition in MSSM! (as long as rightright--handed top handed top squarksquark is lighter than 125 is lighter than 125 GeVGeV))

Carena et al (2008)

Electric Dipole MomentsElectric Dipole MomentsSame CPSame CP--violating phases that produce baryon asymmetry also violating phases that produce baryon asymmetry also give rise to EDMsgive rise to EDMsgive rise to EDMsgive rise to EDMs

If EDM measured, then If EDM measured, then can “predict” baryon can “predict” baryon asymmetryasymmetry

If limit set on EDM, then If limit set on EDM, then limit on MSSM parameter limit on MSSM parameter spacespaceasymmetryasymmetry spacespace

Computing the Baryon AsymmetryComputing the Baryon AsymmetryComputing the Baryon AsymmetryComputing the Baryon AsymmetrySolve Boltzmann equations for Solve Boltzmann equations for particle particle species in the species in the plasma, with plasma, with

background of expanding bubble of broken background of expanding bubble of broken EW symmetryEW symmetry

diffusiondiffusion collisionscollisions CPCP--violating violating sourcesource

nnii = number density for = number density for particles particles —— antiparticlesantiparticles

1. Want to solve for charge densities n1. Want to solve for charge densities nii

(particle number density) (particle number density) (anti(anti particle number density)particle number density)(particle number density) (particle number density) –– (anti(anti--particle number density)particle number density)

2. LH 2. LH fermionfermion charge density generates baryon numbercharge density generates baryon number

Computing the Baryon AsymmetryComputing the Baryon AsymmetryComputing the Baryon AsymmetryComputing the Baryon AsymmetrySolve Boltzmann equations for Solve Boltzmann equations for particle particle species in the species in the plasma, with plasma, with

background of expanding bubble of broken background of expanding bubble of broken EW symmetryEW symmetry

diffusiondiffusion collisionscollisions CPCP--violating violating sourcesource

nnii = number density for = number density for particles particles —— antiparticlesantiparticles

1. CPV source induces 1. CPV source induces HiggsinoHiggsinodensity inside bubble walldensity inside bubble wall

Distance from bubble wallDistance from bubble wall

Cirigliano, Lee, Ramsey-Musolf, S.T. (2006)

Computing the Baryon AsymmetryComputing the Baryon AsymmetryComputing the Baryon AsymmetryComputing the Baryon AsymmetrySolve Boltzmann equations for Solve Boltzmann equations for particle particle species in the species in the plasma, with plasma, with

background of expanding bubble of broken background of expanding bubble of broken EW symmetryEW symmetry

diffusiondiffusion collisionscollisions CPCP--violating violating sourcesource

nnii = number density for = number density for particles particles —— antiparticlesantiparticles

1. CPV source induces 1. CPV source induces HiggsinoHiggsinodensity inside bubble walldensity inside bubble wall

2. 2. HiggsinoHiggsino density diffusesdensity diffuses

Distance from bubble wallDistance from bubble wall

Cirigliano, Lee, Ramsey-Musolf, S.T. (2006)

Computing the Baryon AsymmetryComputing the Baryon AsymmetryComputing the Baryon AsymmetryComputing the Baryon AsymmetrySolve Boltzmann equations for Solve Boltzmann equations for particle particle species in the species in the plasma, with plasma, with

background of expanding bubble of broken background of expanding bubble of broken EW symmetryEW symmetry

diffusiondiffusion collisionscollisions CPCP--violating violating sourcesource

nnii = number density for = number density for particles particles —— antiparticlesantiparticles

1. CPV source induces 1. CPV source induces HiggsinoHiggsinodensity inside bubble walldensity inside bubble wall

2. 2. HiggsinoHiggsino density diffusesdensity diffuses

3. Inelastic scattering produces 3. Inelastic scattering produces leftleft--handed fermionshanded fermions

Distance from bubble wallDistance from bubble wallttLLttLL

Cirigliano, Lee, Ramsey-Musolf, S.T. (2006)ttRR ttRR~~

from from Bjorn Bjorn GarbrechtGarbrechtChung, Garbrecht, Ramsey-Musolf, S.T. (2009, 2009)

Comparison of different groupsComparison of different groupsComparison of different groupsComparison of different groupsVarious results:Various results:

CarenaCarena, , QuirosQuiros, , SecoSeco, Wagner (2000), Wagner (2000)Following Following RiottoRiotto (1997); Lee(1997); Lee, , CiriglianoCirigliano, Ramsey, Ramsey--MusolfMusolf (2004)(2004)

plotted vs. plotted vs. ,,for Mfor M = 200 GeV= 200 GeV CiriglianoCirigliano, Ramsey, Ramsey MusolfMusolf (2004)(2004)for Mfor M22 = 200 GeV= 200 GeV

andand

Factor of 10 Factor of 10 discrepencydiscrepency

BalazsBalazs, , CarenaCarena, , MenonMenon, Morrissey, , Morrissey, Wagner (2004)Wagner (2004)

KonstandinKonstandin, , ProkopecProkopec, Schmidt, , Schmidt, SecoSeco(2005)(2005)

discrepencydiscrepency

EDMs from MSSM phasesEDMs from MSSM phases

TeVTeV--scalescale

New CPNew CP--violating phases in SUSY violating phases in SUSY sector contribute to onesector contribute to one--loop graphsloop graphssector contribute to onesector contribute to one--loop graphsloop graphs

Below the Below the TeVTeV--scalescale

Integrating out SUSY particles Integrating out SUSY particles leaves higher dim EDM operators for leaves higher dim EDM operators for leaves higher dim EDM operators for leaves higher dim EDM operators for SM particlesSM particles

EDMEDM ChromoChromo--EDMEDM

EDMs from MSSM phasesEDMs from MSSM phases

PospelovPospelov & Ritz (2005)& Ritz (2005)

Complicated problem to relate observable EDMs to Complicated problem to relate observable EDMs to the underlying CPthe underlying CP--violating phasesviolating phases

Electric Dipole MomentsElectric Dipole Moments

Three most restrictive EDMs:

R t l (2002)R t l (2002)

Baker et al. (2006)Baker et al. (2006)

Regan et al. (2002)Regan et al. (2002)

RomalisRomalis et al. (2001)et al. (2001)

PospelovPospelov & Ritz (2005), Falk et al (1999)& Ritz (2005), Falk et al (1999)

EDMs in the MSSMEDMs in the MSSM

One‐loop EDMs in MSSM are generally big!“SUSY CP Problem”

MMSUSYSUSY = 500 = 500 GeVGeV

ee

Taking common Taking common susysusy mass, mass, O(1) h l ibl f O(1) h l ibl f ep

ton

epto

nphas

ephas

e

O(1) phases only possible for O(1) phases only possible for MMSUSYSUSY > > TeVTeV

Squar

kSquar

k//sl

esl

e

GauginoGaugino//HiggsinoHiggsino phasephaseLoophole: Assume 1st/2nd generation Loophole: Assume 1st/2nd generation sleptonssleptons//squarkssquarks are heavy are heavy

“Irreducible” two‐loop EDMsIrreducible  two loop EDMs

Even if one‐loop EDMs suppressed, have two‐loop contributionsp pp , p

FirstFirst--order order phase transition phase transition phase transition phase transition + LEP bound on + LEP bound on Higgs massHiggs mass

Gives EDM sensitive to Gives EDM sensitive to squarksquark//sleptonslepton phasephase

Gives EDM sensitive to Gives EDM sensitive to gauginogaugino//HiggsinoHiggsino phasephase

Li, Profumo, Ramsey-Musolf (2008) Pilaftsis (1999); Chang, Chang, Keung (1999)f = u, d, ef = u, d, e

squarksquark//sleptonslepton phasephasegauginogaugino//HiggsinoHiggsino phasephase

Suppressed in MSSM Suppressed in MSSM baryogenesisbaryogenesis

MSSM BaryogenesisMSSM Baryogenesisee oo

//Hig

gsi

no

Hig

gsi

no

ddTlTl ddnn ddHgHg

esis

esis

epto

nep

ton

phas

ephas

e

Gau

gin

Gau

gin

phas

ephas

e

l l bar

yogen

ebar

yogen

e

Squar

kSquar

k//sl

esl

e

Succ

essf

uSucc

essf

u

GauginoGaugino (Wino) mass(Wino) mass

GauginoGaugino//HiggsinoHiggsino phasephase

GauginoGaugino (Wino) mass(Wino) mass

Li, Profumo, Ramsey-Musolf (2008)

Baryogenesis in f hExtensions of the MSSM

Several possibilities:Several possibilities:Several possibilities:Several possibilities:

1. Add new degrees of freedom: Singlet extension of MSSM 1. Add new degrees of freedom: Singlet extension of MSSM e.g. NMSSM, e.g. NMSSM, nMSSMnMSSM, U(1)’MSSM , U(1)’MSSM

Kang, Langacker, Li, Liu (2004)

Balasz, Carena, Menon, Morrissey, Wagner (2004)

Huber and Schmidt (2000)

2. Add new higher2. Add new higher--dimensional operatorsdimensional operators

“Beyond“Beyond--thethe--MSSM” modelMSSM” model Dine, Seiberg, Thomas (2007)

Add dimAdd dim--5 operators to MSSM5 operators to MSSM

For For baryogenesisbaryogenesis: can have light stops/: can have light stops/sbottomssbottoms and still obey and still obey Higgs mass LEP boundHiggs mass LEP bound Blum Nir (2008) Higgs mass LEP boundHiggs mass LEP bound Blum, Nir (2008)

“Irreducible” two‐loop EDMsIrreducible  two loop EDMs

In extensions of the MSSM, both diagrams can be relevant.

“Beyond‐the‐MSSM” scenario: include dim‐5 operators in MSSM

Li, Profumo, Ramsey-Musolf (2008) Pilaftsis (1999); Chang, Chang, Keung (1999)f = u, d, ef = u, d, e

Gives EDM sensitive to Gives EDM sensitive to squarksquark//sleptonslepton phasephase

Gives EDM sensitive to Gives EDM sensitive to gauginogaugino//HiggsinoHiggsino phasephase

Baryogenesis Beyond‐the‐MSSMa yoge es s eyo d t e SS

dd dd dd

has

ehas

e

ddTlTl ddnn ddHgHg

ase

ase

//sle

pto

nsl

epto

nph

ph

slep

ton

slep

ton

pha

pha

Squar

kSquar

k//

Squar

kSquar

k//

GauginoGaugino//HiggsinoHiggsino phasephase GauginoGaugino//HiggsinoHiggsino phasephase

Blum, Delaunay, Losada, Nir, S.T. (in prep)Preliminary results (may change)Preliminary results (may change)

ConclusionsConclusions

• EDMs provide powerful probes of electroweakEDMs provide powerful probes of electroweak baryogenesis in the MSSM

• Future directions:• Future directions:– Experiments will improve sensitivities by orders of magnitudemagnitude

– Theorists will try to find new ways for electroweak baryogenesis to be viablebaryogenesis to be viable