Left-Right Symmetric Models (LRSM)

Overview
EWPT
Flavour constraints
Left-Right Symmetric Models (LRSM)
Luiz Vale
Universit´
e Paris-Sud
S. Descotes-Genon (LPT) and V. Bernard (IPN)
Multi-TeV Probes Summer School, Carg`
ese
July 23rd, 2014
Luiz Vale
Left-Right Symmetric Models (LRSM)
Overview
EWPT
Flavour constraints
LRSM = SU(2)L ⊗ SU(2)R ⊗ U(1)B−L
Motivation: understand why and how parity or charge-conjugation
are not good symmetries of the quantum world.
LR symmetric models have been extensively studied over the last
40 years. Usual picture: triplets ∆R = (1, 3, 2) and ∆L = (3, 1, 2)
T
h∆T
R i = (0, 0, vR ) and h∆L i = (0, 0, vL )
Triplets introduce Majorana masses νRT γ 2 γ 0 σ2 ∆R νR
Setting vR at TeV and light mνL requires large fine-tuning or
new symmetries
The VEV vL is set to zero, otherwise
2 /(cos2 (θ )M 2 ) 6= 1 at tree-level
ρ ≡ MW
W
Z
Luiz Vale
Left-Right Symmetric Models (LRSM)
Overview
EWPT
Flavour constraints
Doublets instead of triplets
Model considered: doublets χR = (1, 2, 1) and χL = (2, 1, 1)
T
hχT
R i = (0, vR ) and hχL i = (0, vL )
Neutrinos are Dirac particles in this minimal picture
ρ = 1 at tree-level
The VEV vL is a free parameter
Luiz Vale
Left-Right Symmetric Models (LRSM)
Overview
EWPT
Flavour constraints
Generalities
Quarks: QL,R
νL,R
uL,R
, and leptons LL,R =
=
`L,R
dL,R
Electric charge: Q = TL3 + TR3 +
B−L
2
˜ R + h.c.,
Yukawa interactions: Q L Y φQR + Q L Y˜ φQ
∗
˜
φ ≡ σ2 φ σ2 .
Bi-doublet scalar field, φ → UL φUR† .
VEVs: hφi = diag(κ1 , κ2 )
Mass matrices: Mu = κ1 Y + κ2 Y˜ and Md = κ1 Y˜ + κ2 Y .
Mixing matrices: VL ≡ V CKM and VR
Relate L to R w/ discrete sym. Under P, VL ' Su VR Sd ;
under C, VL = Ku VR∗ Kd
Luiz Vale
Left-Right Symmetric Models (LRSM)
Overview
EWPT
Flavour constraints
Breaking pattern
SU(2)L ⊗ SU(2)R ⊗ U(1)B−L
gL , gR , g 0
Luiz Vale
Left-Right Symmetric Models (LRSM)
Overview
EWPT
Flavour constraints
Breaking pattern
SU(2)L ⊗ SU(2)R ⊗ U(1)B−L
gL , gR , g 0
↓(vR )
vR & O(1) TeV
SU(2)L ⊗ U(1)Y
New GBs: WR± , ZR
Luiz Vale
Left-Right Symmetric Models (LRSM)
Overview
EWPT
Flavour constraints
Breaking pattern
gL , gR , g 0
vR & O(1) TeV
SU(2)L ⊗ SU(2)R ⊗ U(1)B−L
↓(vR )
SU(2)L ⊗ U(1)Y
↓(κ1,2 ,vL )
0
New GBs: W ± , Z 0
q
κ ≡ κ21 + κ22 + vL2 set
EWSB
Known GBs:
W ± ∼ WL±/ SM , Z ∼ ZSM
U(1)EM
vR 6= vL : vacuum is not P
or C-symmetric
Luiz Vale
Left-Right Symmetric Models (LRSM)
Overview
EWPT
Flavour constraints
Breaking pattern
gL , gR , g 0
vR & O(1) TeV
SU(2)L ⊗ SU(2)R ⊗ U(1)B−L
↓(vR )
SU(2)L ⊗ U(1)Y
↓(κ1,2 ,vL )
0
New GBs: W ± , Z 0
q
κ ≡ κ21 + κ22 + vL2 set
EWSB
Known GBs:
W ± ∼ WL±/ SM , Z ∼ ZSM
U(1)EM
vR 6= vL : vacuum is not P
or C-symmetric
0
Higgs content: contains hSM−like
, 5 heavy (∼ vR ) neutral Higgs, 2
heavy (∼ vR ) charged Higgs
Luiz Vale
Left-Right Symmetric Models (LRSM)
Overview
EWPT
Flavour constraints
Preliminary fit: SMEW @2−loop + LRtree and direct MWR
O
0
σhad
Re
Rµ
AFB (b)
AFB (τ )
ASLD
e
MW
QW (Cs)
...
SM pull
-1.52
-1.17
-1.20
2.79
-1.41
-1.76
-0.85
0.70
...
LR pull
-0.91
-1.36
-1.48
2.73
-1.42
-1.81
-0.65
0.83
...
≡ κ/vR , r ≡ κ2 /κ1 , w ≡ vL /κ1 , tR = tan(θR ) ≡ g 0 /gR , cR = cos(θR )
pull ≡ (Oexp − Ofit |w /o input )/σexp
Suppose MWR & 2 TeV [CMS and ATLAS]
r and w are not constrained by the fit
Luiz Vale
Left-Right Symmetric Models (LRSM)
Overview
EWPT
Flavour constraints
Flavour dynamics
FCNC: Meson oscillations put severe constraints on H 0 when
triplets are considered, O(15) TeV
In the doublet case, preliminary studies indicate that one can
bring it down to O(2) TeV
However, a global fit still needs to be done
Include fermion spectrum, b → sγ, b → c`ν, ...
Higgs potential and VEVs introduce new sources of CPV
Luiz Vale
Left-Right Symmetric Models (LRSM)
Overview
EWPT
Flavour constraints
Thank you for the attention
Luiz Vale
Left-Right Symmetric Models (LRSM)
Overview
EWPT
Flavour constraints
Preliminary fit: correlation w/o MWR as input
Luiz Vale
Left-Right Symmetric Models (LRSM)
Overview
EWPT
Flavour constraints
0
Preliminary fit: correlation σhad
− QW (Cs)
Luiz Vale
Left-Right Symmetric Models (LRSM)

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