Post on 23-Feb-2016
description
1
Claudia FrugiueleCarleton University
MMRSSMLepton number as R symmetry,Sneutrino as down type Higgs
Edinburgh 13/04/2011
q\\\\\\AQ
in collaboration with Thomas Grégoire
2
Outline1. SUSY, MSSM, Rp
2. Continuous R symmetry, MRSSM
3. Our model: MoreMinimalRSSM4. Experimental constraints5. MMRSSM features, and pheno
3
SUPERSYMMETRY
• Most popular solution to the hierarchy problem.
• Symmetry between fermions, and bosons
With same mass and quantum number
4
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
5
MSSM (Minimal Supersymmetric extension of the SM)
Each SM field is promoted to a superfield.
6
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
7
1)Mass and mixing term for sleptons, squarksand higgses.
2) Majorana mass for the gauginos
3) Trilinear couplings
SOFT TERMS
8
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
9
SUSY HIGGS SECTORHd same gauge numbers of a lepton field, but the sneutrino can’t be a Higgs field.
Is it possible Hd L ?
10
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.
11
MSSM SUPERPOTENTIAL
to give mass to the Higgsino
But Lepton and baryon number are not accidental symmetries
ex. fast proton decay
12
Proton decay
Majorana neutrino mass
Strong bounds on these couplings!
fig. hep-ph/0406039v2
13
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!
14
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.
15
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:
16
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!
17
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
18
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]
19
MRSSM Higgs sector
Forbidden by R symmetry
Necessary to give mass to the higgsino
W superpotential R charge 2
20
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?
21
MMRSSM More Minimal MRSSM
R symmetry as Lepton number,sneutrino as down type Higgs
Hd La a=e or μ or τ
22
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
23
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
24
OUR MODEL:
The electronic sneutrino does not carry R charge/lepton number
A sneutrino VeV does not induce a neutrino mass!
25
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
26
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
27
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
28
MMRSSM EXPERIMENTAL CONSTRAINTS
29
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
30
Leptons mixing
va sneutrino VeV
a=e or μ or τ
31
• Constraints from the gauge bosons couplings
• Lepton universality violation
Leptons mixing
32
Leptons mixing• Strongest bounds from the Z0 coupling
GeV
33
Sneutrino VeV bounds
Heavy gauginos, large sneutrino VeV
a=e
a=μ,τ
34
Bounds from Rp violation
Down type Yukawa couplings = Rp violating couplings,
EWPM bounds, no neutrino bounds!
35
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
36
Indirect bounds from EWPM
Contribution to GF
Semileptonic Meson decay
fig. hep-ph/0406039v2
37
Lower bound on sneutrino VeV
Tau Yukawa
Bottom quark Yukawa
Very high tanβ region excluded
38
• Less stringent bounds!ex bottom quark yukawa
Our case
Neutrino bounds
can have a sizeable branching ratio!
39
R symmetry broken by Anomaly mediation
Majorana mass for gauginos
Trilinear scalar coupling
Majorana mass for the neutrino.
40
Neutrino mass generated by Left/Right mixing generated by anomaly mediation
fig. hep-ph/0406039v2
41
R symmetry broken by Anomaly mediation
Bounds on SUSY breakingScale, F <1016 (GeV) 2
Gauge mediation
42
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.)
43
• Unstable• Possible Dark matter candidateBUT…
Gravitino LSP
44
The relic density should be very small
Gravitino LSP
Very low reheating temperature required!
45
Gravitino LSP
TR below the SUSY threshold
GeV
46
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
47
The Model
48
Outline• Mu Bmu problem• Yukawa coupling for the
Higgs/Lepton• Electroweak symmetry breaking • LHC Phenomenology
49
Mu/Bmu problem
Naturalness
X spurion field
Higgsino mass Mixing term
50
Mu/Bmu problem
One loop
One loop
Gauge mediation
Fine tuning!
51
Mu/Bmu problem
One loop
Two loops
Gauge mediation
No fine tuning
52
Mu/Bmu problemOne loop
Two loops
Different operators.
EASYterm
term
53
Mu/Bmu problem
One loop
One loop
Fine tuning!
54
Mu/Bmu problem
Solution inspired bymodel by Giudice,Dvali,Pomarol (1998)
Messenger field
55
Yukawa coupling:
More link fields to add
For
very low scale SUSY breaking
Null, Yukawa coupling generated through SUSY breaking
56
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.
57
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.
58
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.
59
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?