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Claudia FrugiueleCarleton University

MMRSSMLepton number as R symmetry,Sneutrino as down type Higgs

Edinburgh 13/04/2011

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in collaboration with Thomas Grégoire

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Outline1. SUSY, MSSM, Rp

2. Continuous R symmetry, MRSSM

3. Our model: MoreMinimalRSSM4. Experimental constraints5. MMRSSM features, and pheno

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SUPERSYMMETRY

• Most popular solution to the hierarchy problem.

• Symmetry between fermions, and bosons

With same mass and quantum number

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SUPERFIELD contains Fermion/Boson and its SUSY partner Boson/

Fermion

SM fermion bosonic, spin 0, superpartner, sfermions.

SM boson spin ½ fermiongauge boson, gaugino. Higgs, higgsino

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MSSM (Minimal Supersymmetric extension of the SM)

Each SM field is promoted to a superfield.

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1) We do not see scalar electrons or fermionic gluons! Supersymmetry should be broken.

2) Still solution to hierarchy problem as long as SUSY-breaking operators are “soft” (d<4).

SUSY BREAKING

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1)Mass and mixing term for sleptons, squarksand higgses.

2) Majorana mass for the gauginos

3) Trilinear couplings

SOFT TERMS

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SUSY HIGGS SECTOR

Hu mass to the up type fermions Hd mass to the down type fermions.

MSSM Higgs sector two higgs doublets model

Yukawa interactions contained in the superpotential, holomorphic function of the superfields

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SUSY HIGGS SECTORHd same gauge numbers of a lepton field, but the sneutrino can’t be a Higgs field.

Is it possible Hd L ?

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1) Hd is necessary to cancel the Hu anomalies.

2) Sneutrino VeV violates lepton number, constraints on the neutrino mass impose the VeV to be very small.

No it is not.

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MSSM SUPERPOTENTIAL

to give mass to the Higgsino

But Lepton and baryon number are not accidental symmetries

ex. fast proton decay

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Proton decay

Majorana neutrino mass

Strong bounds on these couplings!

fig. hep-ph/0406039v2

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R parity• Typical solution: impose a discrete symmetry called R parity

Fermionic and bosonic component of a superfield have different R parity!

• SM particle even under R parity • SUSY partners odd under it

Distinctive pheno at the LHC!

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Model with R parity violation

We introduce these terms in the superpotential

Couplings are highly constrained from the experimental bounds ( neutrino mass)

Interesting and different pheno at the LHC.

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U(1)R continuous R symmetry

R parity contained in U(1) R continuous symmetry.

U(1)R acts differently on the fermionic andbosonic component of a field:

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U(1)R symmetry

Gauge superfield, fixed R chargeR gauge boson=0

R gauginos=1

SU

Gauginos Majorana mass are forbidden by R symmetry MSSM is not R symmetry invariant

Gauginos should be Dirac fermions!

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Dirac Gauginos

New Adjoints superfields for each SM gauge group to give Dirac mass to the gauginos

Supersoft SUSY breaking operator,Fox, Nelson, Weiner, 2002

D term spurion

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MRSSM

Enlarged Higgs sector, two new doublets Ru Rd

New Adjoints superfields for each SM gauge group to give Dirac mass to the gauginos

arXiv::0712.2039 [hep-ph]

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MRSSM Higgs sector

Forbidden by R symmetry

Necessary to give mass to the higgsino

W superpotential R charge 2

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MRSSM features1)Dirac gauginos2)No left/right mixing as trilinear soft couplings are forbidden by R symmetry3)Enlarged Higgs sector, inert doublets4) Large flavor violation compatible with bounds

Is this the Minimal R symmetric SSM?

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MMRSSM More Minimal MRSSM

R symmetry as Lepton number,sneutrino as down type Higgs

Hd La a=e or μ or τ

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We economized the particle content of the model respect the MRSSM!

One of the sneutrino plays the role of the down type Higgs Hd

Necessary to cancel anomalies and to give mass to the Higgsino

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U(1)R lepton number, ex. here electron number

SM particle don’t carry R charge beside electron and its neutrino.SUSY partners carry all R charge besides the slectron,and the electronic sneutrino

Ex:Qi R charge 1, fermion R charge 1-1=0

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OUR MODEL:

The electronic sneutrino does not carry R charge/lepton number

A sneutrino VeV does not induce a neutrino mass!

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More minimal particle content of the model respect the MRSSM!

Just two Higgs doublets as in the MSSM, one is inert as the lepton field gives mass to the down type fermions

Need just to add the adjoints superfields to the MSSM spectrum

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OUR MODEL:

MMRSSM superpotential

Down type Yukawa couplings= Rp violating couplings

SU

is nulll. Yukawa coupling for the electron is generated by SUSY breaking

Higgsino mass

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Rp parity and our symmetry

Rp violating couplings

Standard Rp parity is violated as our R symmetry is not the usual R symmetry (ex:MRSSM), but it is one of the lepton number

SU

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MMRSSM EXPERIMENTAL CONSTRAINTS

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MMRSSM Experimental constraints:

No constraints from neutrino mass, but..

1) Neutrino and electron mixes with adjoints fermions.2) Other Rp violating couplings bounds3) R symmetry breaking by anomaly mediation4) Cosmological bounds

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Leptons mixing

va sneutrino VeV

a=e or μ or τ

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• Constraints from the gauge bosons couplings

• Lepton universality violation

Leptons mixing

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Leptons mixing• Strongest bounds from the Z0 coupling

GeV

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Sneutrino VeV bounds

Heavy gauginos, large sneutrino VeV

a=e

a=μ,τ

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Bounds from Rp violation

Down type Yukawa couplings = Rp violating couplings,

EWPM bounds, no neutrino bounds!

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Trilinear Rp violating couplings induce neutrino mass, in our case they don’t. Majorana neutrino mass forbidden by R symmetry

Less strong bounds! fig. hep-ph/0406039v2

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Indirect bounds from EWPM

Contribution to GF

Semileptonic Meson decay

fig. hep-ph/0406039v2

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Lower bound on sneutrino VeV

Tau Yukawa

Bottom quark Yukawa

Very high tanβ region excluded

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• Less stringent bounds!ex bottom quark yukawa

Our case

Neutrino bounds

can have a sizeable branching ratio!

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R symmetry broken by Anomaly mediation

Majorana mass for gauginos

Trilinear scalar coupling

Majorana mass for the neutrino.

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Neutrino mass generated by Left/Right mixing generated by anomaly mediation

fig. hep-ph/0406039v2

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R symmetry broken by Anomaly mediation

Bounds on SUSY breakingScale, F <1016 (GeV) 2

Gauge mediation

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Low scale SUSY breaking:Gauge mediation

Low scale SUSY breaking

No gravity mediation.

R-symmetric gauge mediation

Several models (J. Amigo et al., JHEP 0901 (2009) 018, K.Benakli,M.GoodsellNucl.Phys. B816 (2009) 185–203,L.M Carpenter arXiv:1007.0017.)

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• Unstable• Possible Dark matter candidateBUT…

Gravitino LSP

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The relic density should be very small

Gravitino LSP

Very low reheating temperature required!

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Gravitino LSP

TR below the SUSY threshold

GeV

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Summary:

1) The sneutrino VeV can be quite large for fairly heavy gauginos,

2) Stronger Rp violation than in the usual scenario, expect phenomenological consequence,

3) Low scale SUSY breaking 4) Gravitino is not dark matter

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The Model

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Outline• Mu Bmu problem• Yukawa coupling for the

Higgs/Lepton• Electroweak symmetry breaking • LHC Phenomenology

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Mu/Bmu problem

Naturalness

X spurion field

Higgsino mass Mixing term

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Mu/Bmu problem

One loop

One loop

Gauge mediation

Fine tuning!

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Mu/Bmu problem

One loop

Two loops

Gauge mediation

No fine tuning

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Mu/Bmu problemOne loop

Two loops

Different operators.

EASYterm

term

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Mu/Bmu problem

One loop

One loop

Fine tuning!

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Mu/Bmu problem

Solution inspired bymodel by Giudice,Dvali,Pomarol (1998)

Messenger field

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Yukawa coupling:

More link fields to add

For

very low scale SUSY breaking

Null, Yukawa coupling generated through SUSY breaking

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EWSB:MSSM scalar potential with

No mu term for the sneutrino.

Rd does not develop a VeV, it is an inert doublet

Rd necessary to cancel the Hu anomalies and to give mass to the higgsino.

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MMRSSM Phenomelogy(work in progress)

Our R symmetry impose that ALL the decay chainsshould end with electrons or electronic neutrinos.

Lightest Ra particles charged lepton and neutrinos.

Multileptons signature at the LHC.

Pheno similar to Rp violating models.

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MMRSSM Phenomelogy

LEPTO SQUARK Shorter decay chain!

But shorter decay and Dirac gauginos as smoking gun.

Stronger Rp violation in our model

Usual scenario Rp effects felt just in the decay.

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CONCLUSIONS• MMRSSM minimal particle content• The sneutrino is the down type higgs!• Interesting LHC phenomenology• Interesting possible scenario for neutrino

model building • MMRSSM Dark matter candidate ?

Axino/Axions sector?