Electroweak scale neutrinos and Higgses Alfredo Aranda Facultad de - - PowerPoint PPT Presentation

Electroweak scale neutrinos and Higgses

Alfredo Aranda

Facultad de Ciencias - Universidad de Colima Dual CP Institute of High Energy Physics

XIII Mexican School of Particles and Fields - 2008

Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 1 / 33

Outline

1

Standard Model Particle Content Gauge Structure The missing ingredient

2

Beyond the Standard Model Experimental Evidence Pseudo-experimental evidence Theoretical evidence Going beyond

3

Minimal model Electroweak scale additions The Model

4

Model with Higgs triplets Additional field content Virtues

5

Conclusions

Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 2 / 33

Standard Model Particle Content

Particle Content

Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 3 / 33

Standard Model Gauge Structure

Gauge Structure. interactions

1

SU(3)C× SU(2)W× U(1)Y

2

8 gluon fields for the Strong interaction.

3

3 gauge fields for the Weak interaction.

4

1 gauge field for the Electromagnetic interaction.

Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 4 / 33

Standard Model Gauge Structure

Gauge Structure. interactions

1

SU(3)C× SU(2)W× U(1)Y

2

8 gluon fields for the Strong interaction.

3

3 gauge fields for the Weak interaction.

4

1 gauge field for the Electromagnetic interaction. νe e−

• L

νµ µ−

• L

ντ τ −

• L

u d

• L

c s

• L

t b

• L

eR µR τR uR dR cR sR tR bR

Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 4 / 33

Standard Model The missing ingredient

Higgs - The missing ingredient. Massive force carriers!

1

Principle of Gauge Symmetry → Massless Gauge bosons.

2

Massive Gauge bosons → inconsistent theory!

3

Solution: Spontaneous Symmetry Breaking - Higgs Mechanism

Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 5 / 33

Standard Model The missing ingredient

Higgs - The missing ingredient. Massive force carriers!

1

Principle of Gauge Symmetry → Massless Gauge bosons.

2

Massive Gauge bosons → inconsistent theory!

3

Solution: Spontaneous Symmetry Breaking - Higgs Mechanism SM predicts the existence of a new particle, the Higgs.

Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 5 / 33

Standard Model The missing ingredient

Higgs - The missing ingredient. Massive force carriers!

1

Principle of Gauge Symmetry → Massless Gauge bosons.

2

Massive Gauge bosons → inconsistent theory!

3

Solution: Spontaneous Symmetry Breaking - Higgs Mechanism

Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 5 / 33

Beyond the Standard Model Experimental Evidence

Why go beyond the Standard Model? Experimental Evidence

1

Neutrinos are MASSIVE.

2

Baryon Asymmetry - A mystery.

3

Dark Matter

4

Dark Energy

Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 6 / 33

Beyond the Standard Model Experimental Evidence

Why go beyond the Standard Model? Experimental Evidence

1

Neutrinos are MASSIVE.

2

Baryon Asymmetry - A mystery.

3

Dark Matter

4

Dark Energy

Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 6 / 33

Beyond the Standard Model Experimental Evidence

Why go beyond the Standard Model? Experimental Evidence

1

Spectrum of fermion masses.

Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 7 / 33

Beyond the Standard Model Experimental Evidence

Why go beyond the Standard Model? Experimental Evidence

1

Spectrum of fermion masses.

Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 7 / 33

Beyond the Standard Model Pseudo-experimental evidence

Why go beyond the Standard Model? Pseudo-experimental Evidence

1

Gauge coupling unification.

Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 8 / 33

Beyond the Standard Model Pseudo-experimental evidence

Why go beyond the Standard Model? Pseudo-experimental Evidence

1

Gauge coupling unification.

Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 8 / 33

Beyond the Standard Model Pseudo-experimental evidence

Why go beyond the Standard Model? Pseudo-experimental Evidence

1

Gauge Hierarchy problem.

Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 9 / 33

Beyond the Standard Model Pseudo-experimental evidence

Why go beyond the Standard Model? Pseudo-experimental Evidence

1

Gauge Hierarchy problem.

Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 9 / 33

Beyond the Standard Model Theoretical evidence

Why go beyond the Standard Model? Theoretical Evidence

1

GRAVITY.

Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 10 / 33

Beyond the Standard Model Going beyond

How do we go beyond the Standard Model? Approaches

1

Grand Unified Theories.

2

Supersymmetry.

3

Extra dimensions.

4

♦

Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 11 / 33

Beyond the Standard Model Going beyond

How do we go beyond the Standard Model? Approaches

1

Grand Unified Theories.

2

Supersymmetry.

3

Extra dimensions.

4

♦ Paradigm: Something is happening at high (very high) energy scales.

Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 11 / 33

Minimal model Electroweak scale additions

Minimalistic additions Proposal

1

Any addition to the Standard Model should NOT introduce higher energy scales a.

2

Effects of additions should be testable at future accelerators: LHC/ILC

aA.A, Omar Blanno and J. Lorenzo Díaz-Cruz, Physics Letters B 660, 62-66 (2008) Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 12 / 33

Minimal model Electroweak scale additions

Right-handed neutrinos at the Electroweak scale The model SM particle content and gauge interactions. Existence of 3 RH neutrinos with a mass scale of EW size. Global U(1)L spontaneously (and/or explicitly) broken at the EW scale by a single complex scalar field. Higgs sector: SU(2)L doublet Higgs field Φ and a SM singlet complex scalar field η.

Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 13 / 33

Minimal model The Model

Neutrino and scalar sector The Lagrangian LνH = Lνy − V , with Lνy = −yαi¯ LαNRiΦ − 1 2Zijη ¯ Nc

RiNRj + h.c. ,

V = µ2

DΦ†Φ + λ

2

• Φ†Φ

2 + µ2

Sη∗η + λ′ (η∗η)2

+ κ

• ηΦ†Φ + h.c.
• + λm
• Φ†Φ
• (η∗η) .

Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 14 / 33

Minimal model The Model

Breaking the symmetry Φ =

• φ0+v

√ 2

• and η = ρ + u + iσ

√ 2 , (1)

Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 15 / 33

Minimal model The Model

Breaking the symmetry Φ =

• φ0+v

√ 2

• and η = ρ + u + iσ

√ 2 , (1) Scalar masses M2

S =

• λv2

vu(λm − √ 2r) vu(λm − √ 2r) 2λ′u2 +

1 √ 2rv2

• (2)

M2

σ = rv2

√ 2 (3)

Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 15 / 33

Minimal model The Model

Physical states H =

• φ0

ρ

• =

cos α − sin α sin α cos α h H

• (4)

Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 16 / 33

Minimal model The Model

Physical states H =

• φ0

ρ

• =

cos α − sin α sin α cos α h H

• (4)

Lagrangian Lνy ⊃

• − yαi

√ 2 ¯ νLαNRi(cα h − sα H) + h.c.

• −
• i

2 √ 2 Zij ¯ Nc

RiNRjσ + h.c.

• −
• 1

2 √ 2 Zij ¯ Nc

RiNRj(sα h + cα H) + h.c

• .

(5)

Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 16 / 33

Minimal model The Model

Neutrino masses Seesaw mν =

• mD

mD MM

• (6)

(mD)αi = yαiv/ √ 2 Consider the third family (2 × 2 matrix) Assume mD << MM → m1 = −m2

D/MM and m2 = MM

Requiring m1 ∼ O(eV) and m2 ∼ (10 − 100) GeV leads to yτi ≤ 10−6 (comparable to Yukawa coupling of the electron).

Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 17 / 33

Minimal model The Model

Neutrino eigenstates ντ = cos θ νL1 + sin θ νR2 N = − sin θ νL1 + cos θ νR2

with θ = p mD/m2 ≈ 10−(5−6). Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 18 / 33

Minimal model The Model

Neutrino eigenstates ντ = cos θ νL1 + sin θ νR2 N = − sin θ νL1 + cos θ νR2

with θ = p mD/m2 ≈ 10−(5−6).

Relevant terms L ⊃ h

• ¯

νc

L1νL1

• − Z

2 √ 2 s2

θsα

• + ¯

νc

R2νR2

• − Z

2 √ 2 c2

θsα

• + h.c.
• +

¯ νL1νR2 yν √ 2 (s2

θ − c2 θ)cα

• + ¯

νR2νL1 yν √ 2 (s2

θ − c2 θ)cα

• where y∗

ν = yν and Z ≡ Z11

Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 18 / 33

Minimal model The Model

Higgs decays Γ(h → ¯ ν1ν1) = mh 64π|Z|2s4

θs2 α

Γ(h → ¯ ν2ν2) = mh 64π|Z|2c4

θs2 α

• 1 − 4m2

2

m2

h

3/2 Γ(h → ¯ ν1ν2) = mh 16πy2

ν (s2 θ − c2 θ)2c2 α

• 1 − m2

2

m2

h

2

Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 19 / 33

Minimal model The Model

Possible signatures

Higgs decay ν2 → ν1Z ∗ ν2 → lW ∗ ν2 → ν1γ h → ν1ν2 l+l− + X l + l′ + X γ + X q¯ q + X l + q¯ q′ + X h → ν2ν2 l+l− + l+l− + X l + l′ + l′′ + l′′′ + X l+l− + q¯ q + X l + l′ + l′′ + q¯ q + X γ + γ + X q¯ q + q¯ q + X l + l′ + q¯ q + q¯ q + X h → ν1ν1

• Alfredo Aranda (Colima - DCPIHEP)

EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 20 / 33

Minimal model The Model

Higgs Branching ratios

105 120 135 150 165 180 195 210 225 240

mh (GeV)

0.001 0.01 0.1 1

BR (h ----> XX)

ν2 ν2 ( cα = 0.1) bb ( cα = 0.5) ZZ ( cα = 0.1) ν2 ν2 ( cα = 0.5) ν2 ν2 ( cα = 0.9) τ τ

( cα = 0.9)

bb ( cα = 0.9)

m2 = 10 GeV

WW ( cα = 0.1) WW ( cα = 0.5) WW ( cα = 0.9) ZZ ( cα = 0.5) ZZ ( cα = 0.9)

Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 21 / 33

Minimal model The Model

Higgs Branching ratios

120 140 160 180 200 220 240

mh (GeV)

0.001 0.01 0.1 1

BR (h ----> XX)

ν2 ν2 ( cα = 0.1) τ τ

( cα = 0.5)

bb ( cα = 0.5) bb ( cα = 0.1) τ τ

( cα = 0.1)

ν2 ν2 ( cα = 0.5) ν2 ν2 ( cα = 0.9) τ τ

( cα = 0.9)

bb ( cα = 0.9)

m2 = 60 GeV

ZZ ( cα = 0.1) ZZ ( cα = 0.5) ZZ ( cα = 0.9) WW ( cα = 0.1) WW ( cα = 0.5) WW ( cα = 0.9)

Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 22 / 33

Minimal model The Model

Higgs Branching ratios

150 160 170 180 190 200 210 220 230 240 250

mh (GeV)

0.001 0.01 0.1 1

BR (h ----> XX)

ν2 ν2 ( cα = 0.1) τ τ bb ( cα = 0.5) bb ( cα = 0.1)

WW ( cα = 0.1)

ν2 ν2 ( cα = 0.5) ν2 ν2 ( cα = 0.9)

WW ( cα = 0.9)

bb ( cα = 0.9)

m2 = 100 GeV

WW ( cα = 0.5) ZZ ( cα = 0.1) ZZ ( cα = 0.9) ZZ ( cα = 0.5)

Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 23 / 33

Minimal model The Model

Neutrino decay

3

f p f p

2

(B + C )

γ γ

µ

5

V

1

p l q p (a + b )

γ γ

ν

5

ν 2

Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 24 / 33

Minimal model The Model

2 - body Γ = (B2 + C2)(m2

2 − M2 v )2(1 + 2 M2

v

m2

2 )

8πM2

v m2 2

. 3 - body Γ = m5

2

384π3M4

v

• (B2 + C2)(a2

f + b2 f )

• ,

Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 25 / 33

Model with Higgs triplets Additional field content

A model with Higgs triplets

Additional fields a SU(2)W U(1)Y LM

R =

• νR eM

R

• 2

˜ χ =

• χ0 χ+ χ++T

3 −2 ξ =

• ξ+ ξ0 ξ+T

3 eM

L

1 φS 1 An additional U(1)M under which LM

R , eM L → eiθMLM R , eM L ;

˜ χ → e−2iθM ˜ χ, φS → e−iθMφS

aAA, J. Hernández-Sánchez and P

.Q Hung; arXiv:0809.2791

Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 26 / 33

Model with Higgs triplets Virtues

Virtues Since νR is not an SU(2)L singlet, it does not couple to ¯ LL ˜ Φ The Dirac mass for neutrinos comes from the term LS = −gsl¯ LLφSLM

R + h.c. which leads to MD ν = gslvs.

The Dirac mass for neutrinos is independent of the EW scale The U(1)M symmetry forbids the terms gLLT

L σ2τ2 ˜

χLL and LT

L σ2τ2 ˜

χLM

R at tree level.

The Dirac mass for the neutrinos comes from vs and ML arises at the one-loop level and can be much smaller than MR.

Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 27 / 33

Model with Higgs triplets Virtues

Neutrino masses Majorana mass matrix: M = ML mD

ν

mD

ν

MR

• where ML ∼ ǫ(mD

ν )2/MR < 10−2(mD ν )2/MR.

If gsl ∼ O(gM) and vM >> vS → −(g2

sl/gM)(vs/vm)vs(1 − ǫ) and

MR, where ǫ < 10−2 Since vM ∼ ΛEW, and mν ≤ 1 eV vS ≈

• (1eV) × vM ∼ O(105−6eV)

Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 28 / 33

Model with Higgs triplets Virtues

Scalar phenomenology χ++ Doubly charged Higgs → interesting phenomenology. Different from that of the general two triplets model due to the following

• bservations:

Due to the U(1)M symmetry of the model the decay Γ(χ++ → l+l+) is not present. Specific modes of the model: Γ(χ++ → lM

i

lM

j ) and

Γ(χ++ → l φS lM) or even Γ(χ++ → llφSφS).

Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 29 / 33

Model with Higgs triplets Virtues

χ++ decays Relevant decays B(χ++ → l+

Ml+ M)

B(χ++ → W +W +) B(χ++ → H+

3 W +)

B(χ++ → l+νW +) B(χ++ → l+φSl+

M)

Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 30 / 33

Model with Higgs triplets Virtues

χ++ branching ratios

200 225 250 275 300 325

mH5 (GeV)

1e-05 0.0001 0.001 0.01 0.1 1

Branching Ratio sinθΗ = 0.34

H3 W lM lM l ν W l φs lM W W mlm = 50 GeV mH3 = 200 GeV mφs = 10 GeV

200 225 250 275 300 325

mH5 (GeV)

1e-05 0.0001 0.001 0.01 0.1 1

Branching Ratio sinθΗ = 0.64

H3 W lM lM l ν W l φs lM W W mlm = 50 GeV mH3 = 200 GeV mφs = 10 GeV

200 225 250 275 300 325

mH5 (GeV)

1e-05 0.0001 0.001 0.01 0.1 1

Branching Ratio sinθΗ = 0.89

H3 W lM lM l ν W l φs lM W W mlm = 50 GeV mH3 = 200 GeV mφs = 10 GeV

Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 31 / 33

Model with Higgs triplets Virtues

χ++ branching ratios

200 225 250 275 300 325

mH5 (GeV)

1e-05 0.0001 0.001 0.01 0.1 1

Branching Ratio sinθΗ = 0.34

H3 W lM lM l ν W l φs lM W W mlm = 100 GeV mH3 = 200 GeV mφs = 10 GeV

200 225 250 275 300 325

mH5 (GeV)

1e-05 0.0001 0.001 0.01 0.1 1

Branching Ratio sinθΗ = 0.64

H3 W lM lM l ν W l φs lM W W mlm = 100 GeV mH3 = 200 GeV mφs = 10 GeV

200 225 250 275 300 325

mH5 (GeV)

1e-05 0.0001 0.001 0.01 0.1 1

Branching Ratio sinθΗ = 0.89

H3 W lM lM l ν W l φs lM W W mlm = 100 GeV mH3 = 200 GeV mφs = 10 GeV

Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 32 / 33

Conclusions

Final remarks

1

Minimal testable extensions of the SM lead to interesting phenomenology

2

Addition of EW scale RH neutrinos and a complex scalar

3

Role of the MAJORON - underway

Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 33 / 33

Conclusions

Final remarks

1

Minimal testable extensions of the SM lead to interesting phenomenology

2

Addition of EW scale RH neutrinos and a complex scalar

3

Role of the MAJORON - underway

1

Triplet Higgses and RH neutrinos might be related

2

Seesaw testable at colliders!

3

Rich and testable phenomenology

Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 33 / 33