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Beyond the Standard Model - Lunds universitethome.thep.lu.se/fytn04/Lecture14.pdf · Supersymmetry...
Transcript of Beyond the Standard Model - Lunds universitethome.thep.lu.se/fytn04/Lecture14.pdf · Supersymmetry...
Problems with the SMGrand Unification
Supersymmetryˇ
Beyond the Standard Model
Leif Lönnblad
Institutionen för Astronomioch teoretisk fysikLunds Universitet
2018-12-17
FYTN04: BSM 1 Leif Lönnblad Lund University
Problems with the SMGrand Unification
Supersymmetryˇ
UnconstrainedArbitrary
ˇIncomplete
The standard model and why we hate it!
I There are too many free parameters. Twelve fermionmasses, eight mixing parameters, three couplings and thehiggs field parameters (µ, λ)⇔ (mh,mZ ). In total 25parameters (26 assuming there is CP-violation in QCD)Wouldn’t it be much nicer if we had a theory where thesecould be predicted?
I Unnaturally (?) large scale ratios:me/mν ∼ 107, mW/me ∼ 105, mPl/mW ∼ 1017
FYTN04: BSM 2 Leif Lönnblad Lund University
Problems with the SMGrand Unification
Supersymmetryˇ
UnconstrainedArbitrary
ˇIncomplete
Arbitrary
I Why are there three generations.I Why are the left-handed fermions in SU(2) doublets and
the right-handed in singlets?I Why do we just have SU(3)× SU(2)×U(1)? Nature could
have picked any symmetry!I Why is there charge quantization? In principle Y in U(1)
could be anything.
FYTN04: BSM 3 Leif Lönnblad Lund University
Problems with the SMGrand Unification
Supersymmetryˇ
ˆ ArbitraryIncomplete
ˇFine-tuned?
Incomplete
I Where is the anti-matter?I Where is gravity?I Where is dark matter?I Where is dark energy?
FYTN04: BSM 4 Leif Lönnblad Lund University
Problems with the SMGrand Unification
Supersymmetryˇ
ˆ IncompleteFine-tuned?
Fine-tuned?
There is a problem with the Higgs mass.
Just as couplings are renormalized to be scale dependent, soare masses:
m→ m
(1 +
α
3π
∫ ∞m2
0
dp2
p2 + . . .
)→ m
(1 +
α
3πln
Λ2
m20
+ . . .
)
This comes from self-energy diagrams
= + + +
For the Higgs we find that∫ dp2
p2 →∫
dp2 and we have aquadratic divergence.
FYTN04: BSM 5 Leif Lönnblad Lund University
Problems with the SMGrand Unification
Supersymmetryˇ
ˆ IncompleteFine-tuned?
Assuming the Higgs mass at the scale Λ is mh(Λ), looking onlyat the top-loop we have
m2h(mZ ) ∼ m2
h(Λ)− (Λ2 −m2t )
If there is no physics below mPl, that means mh(mZ ) ≈ 125 GeVcomes from the subtraction between two huge numbers.
FYTN04: BSM 6 Leif Lönnblad Lund University
Problems with the SMGrand Unification
Supersymmetryˇ
ˆ IncompleteFine-tuned?
Consensus
There must be something beyond the Standard Model!
The big questions: What? and Where?
FYTN04: BSM 7 Leif Lönnblad Lund University
Problems with the SMGrand Unification
Supersymmetryˇ
ˆ IncompleteFine-tuned?
Consensus
There must be something beyond the Standard Model!
The big questions: What? and Where?
FYTN04: BSM 7 Leif Lönnblad Lund University
Problems with the SMGrand Unification
Supersymmetryˇ
SU(5)GUTMultiplets
ˇNew bosons
Grand Unification
We know about spontaneous symmetry breaking
U(1)Y × SU(2)L → U(1)EM
Imagine that at a high scale all three forces are united into oneunder a common larger symmety group GGUT.
For some reason this group is then spontaneously broken
GGUT → SU(3)QCD × U(1)Y × SU(2)L
Let’s try G = SU(5)
FYTN04: BSM 8 Leif Lönnblad Lund University
Problems with the SMGrand Unification
Supersymmetryˇ
SU(5)GUTMultiplets
ˇNew bosons
Grand Unification
We know about spontaneous symmetry breaking
U(1)Y × SU(2)L → U(1)EM
Imagine that at a high scale all three forces are united into oneunder a common larger symmety group GGUT.
For some reason this group is then spontaneously broken
GGUT → SU(3)QCD × U(1)Y × SU(2)L
Let’s try G = SU(5)
FYTN04: BSM 8 Leif Lönnblad Lund University
Problems with the SMGrand Unification
Supersymmetryˇ
SU(5)GUTMultiplets
ˇNew bosons
SU(5)GUT
I Simplest possible groupI Invented by Georgi and Glashow 1974I Excluded by data — but still instructive
FYTN04: BSM 9 Leif Lönnblad Lund University
Problems with the SMGrand Unification
Supersymmetryˇ
SU(5)GUTMultiplets
ˇNew bosons
The basic multiplet is given by a colourtriplet and a weak doublet in an (anti-)quintet.
Since the weak doublet is left-handed, thequarks need to be left-handed and weaksinglets, so we use the d .
U5 =
dr
db
dg
(e−
νe
)
L
Group generators are traceless N × N matrices, where thediagonal generator will give the charge and requires
∑Qi = 0.
This gives us charge quantisation and 3Qd + Qe = 0
FYTN04: BSM 10 Leif Lönnblad Lund University
Problems with the SMGrand Unification
Supersymmetryˇ
SU(5)GUTMultiplets
ˇNew bosons
Where are the other quarks and leptons?
The quintet of right-handed fields:
U5 = (dr ,dg ,db,e+, νe)R
The anti-symmetric decuplet with ten left-handed fields
U10 =1√2
0 ub −ug−ub 0 urug −ur 0
−ur −dr−ug −dg−ub −db
ur ug ubdr dg db
(0 −e+
e+ 0
)
L
and the corresponding one for the right-handed fields.
FYTN04: BSM 11 Leif Lönnblad Lund University
Problems with the SMGrand Unification
Supersymmetryˇ
SU(5)GUTMultiplets
ˇNew bosons
Where are the other quarks and leptons?
The quintet of right-handed fields:
U5 = (dr ,dg ,db,e+, νe)R
The anti-symmetric decuplet with ten left-handed fields
U10 =1√2
0 ub −ug−ub 0 urug −ur 0
−ur −dr−ug −dg−ub −db
ur ug ubdr dg db
(0 −e+
e+ 0
)
L
and the corresponding one for the right-handed fields.
FYTN04: BSM 11 Leif Lönnblad Lund University
Problems with the SMGrand Unification
Supersymmetryˇ
SU(5)GUTMultiplets
ˇNew bosons
Where are the other quarks and leptons?
The quintet of right-handed fields:
U5 = (dr ,dg ,db,e+, νe)R
The anti-symmetric decuplet with ten left-handed fields
U10 =1√2
0 ub −ug−ub 0 urug −ur 0
−ur −dr−ug −dg−ub −db
ur ug ubdr dg db
(0 −e+
e+ 0
)
L
and the corresponding one for the right-handed fields.
FYTN04: BSM 11 Leif Lönnblad Lund University
Problems with the SMGrand Unification
Supersymmetryˇ
ˆ MultipletsNew bosons
ˇThe GUT scale
The gauge bosons
SU(5) has 52 − 1 = 24 generators
A =
gij − 2B√30δij
Xr YrXg YgXb Yb
Xr Xg XbYr Yg Yb
(W 3√
2+ 3B√
30W +
W− −W 3√
2+ 3B√
30
)
Giving us 12 new gauge bosons!
FYTN04: BSM 12 Leif Lönnblad Lund University
Problems with the SMGrand Unification
Supersymmetryˇ
ˆ New bosonsThe GUT scaleInteractions
The GUT scale
At some large scale SU(5) is an exact symmetry with a singlecoupling g5.
We expect all SM couplings to come together at some highscale MGUT.
Remember:1
αi(M2)=
1αi(µ2)
+bi
4πln
M2
µ2
with b3 = 11− 4nF/3, b2 = 22/3− 4nF/3, b′1 = −4nF/3
FYTN04: BSM 13 Leif Lönnblad Lund University
Problems with the SMGrand Unification
Supersymmetryˇ
ˆ New bosonsThe GUT scaleInteractions
We should have eg.
1α3(µ2)
+b3
4πln
M2GUTµ2 =
1α2(µ2)
+b2
4πln
M2GUTµ2
using 1/α2(m2Z ) ≈ 30 and 1/α3(m2
Z ) ≈ 10 we get
MGUT ∼ 1018 GeV
FYTN04: BSM 14 Leif Lönnblad Lund University
Problems with the SMGrand Unification
Supersymmetryˇ
ˆ New bosonsThe GUT scaleInteractions
Even if we haven’t specified the way the GUT is broken weshould be able to estimate e.g. the ratio between g1 and g2 atlower energies.
Let’s look at the covariant derivative of SU(5)
Dµ = ∂µ − ig5TaUµa
And Pick out the parts relevant to the electro-weak sector using
Bµ = Aµ cos θW + Zµ sin θW
Wµ3 = −Aµ sin θW + Zµ cos θW
FYTN04: BSM 15 Leif Lönnblad Lund University
Problems with the SMGrand Unification
Supersymmetryˇ
ˆ New bosonsThe GUT scaleInteractions
Dµ = ∂µ − ig5(T3Wµ3 + T1Bµ + . . .)
= ∂µ − ig5 sin θW (T3 + cot θW T1)Aµ + . . .
= ∂µ − ieQAµ + . . .
Identify e = g5 sin θW and Q = T3 − cot θW T1 ≡ T3 + cT1.
Now, for any representation, R, of a group we haveorthogonality and equal normalization of the generators Ta, sothat
TrRTaTb = NRδab
FYTN04: BSM 16 Leif Lönnblad Lund University
Problems with the SMGrand Unification
Supersymmetryˇ
ˆ New bosonsThe GUT scaleInteractions
TrQ2 = Tr(T3 + cT1)2 = (1 + c2)TrT 23
since TrT 23 = TrT 2
1 and
sin2 θW =1
1 + c2 =TrT 2
3TrQ2 =
0 + 0 + 0 +(1
2
)2+(1
2
)2(13
)2+(1
3
)2+(1
3
)2+ 1 + 0
=38
Including the running of the couplings we can get close tosin2 θW ≈ 0.23 at around mZ .
FYTN04: BSM 17 Leif Lönnblad Lund University
Problems with the SMGrand Unification
Supersymmetryˇ
ˆ New bosonsThe GUT scaleInteractions
Interactions
How does the new gauge bosons interact?
looking at the terms when we sanwich the gauge boson matrix,A, between the fundamental representations
U5AU5, U10AU5 and U10AU10
we get eg.
X → uu, X → e+d , Y → ud , Y → d νe, Y → e+u
Giving the charges 4/3 and 1/3 for X and Y .
FYTN04: BSM 18 Leif Lönnblad Lund University
Problems with the SMGrand Unification
Supersymmetryˇ
ˆ New bosonsThe GUT scaleInteractions
Decaying protons!
p = u ud → u Y → u ue+ → π0e+
Remembering the muon width we estimate
Γp ∝ α25
m5p
m4Y
and with mY ∼ mGUT ∼ 1015 GeV we get τp ∼ 1031±2 years.
(The current limit p → π0e+ is τp > 1033 years.)
FYTN04: BSM 19 Leif Lönnblad Lund University
Grand UnificationˆSupersymmetry
(Super) String Theory
New particlesR-parity
ˇFine-tuning solved?
Supersymmetry
Postulate there being a symmetry between fermions andbosons, with an operator Q changing one into the other
|bi〉 = Q|fi〉 and |fi〉 = Q|bi〉
but leaving any other quantum number unchanged.
The transformation is actually defined in terms of an algebrawhere
{Q, Q} = QQ + QQ = 2σµPµ
where Pµ = i∂µ is a translation.
FYTN04: BSM 20 Leif Lönnblad Lund University
Grand UnificationˆSupersymmetry
(Super) String Theory
New particlesR-parity
ˇFine-tuning solved?
normal partner spinqL qL 0 squarksqR qR 0 (can mix)lL lL 0 sleptonslR lR 0 (also mix)νL νL 0 sneutrinos
FYTN04: BSM 21 Leif Lönnblad Lund University
Grand UnificationˆSupersymmetry
(Super) String Theory
New particlesR-parity
ˇFine-tuning solved?
g g 1/2 gluino
γ (γ) 1/2 (photino zino higgsino)Z 0 (Z ) 1/2 all mix together intoh0 1/2 neutralinos χ0
iH0 (H) 1/2 2 + 3 + 1 + 1 + 1 = 8 spin states for the bosonsA0 1/2 gives four neutralinos with two spin states each.
W± W± 1/2 (wino higgsino) mix togetherH± H± 1/2 charginos χ±i
We need an extra higgs doublet (4 new higgs particles):
FYTN04: BSM 22 Leif Lönnblad Lund University
Grand UnificationˆSupersymmetry
(Super) String Theory
New particlesR-parity
ˇFine-tuning solved?
In the simplest version of SUSY (MSSM) we can derive massrelations for the Higgs particles, and get mh < mZ < mH .
But there are many ways of constructing SUSY.
If SUSY was an exact theory we would have mq = mq and itwould be easy to find the new particles.
Since we have not found any sparticles, SUSY is broken.
There are many ways of breaking SUSY.
FYTN04: BSM 23 Leif Lönnblad Lund University
Grand UnificationˆSupersymmetry
(Super) String Theory
New particlesR-parity
ˇFine-tuning solved?
In the simplest version of SUSY (MSSM) we can derive massrelations for the Higgs particles, and get mh < mZ < mH .
But there are many ways of constructing SUSY.
If SUSY was an exact theory we would have mq = mq and itwould be easy to find the new particles.
Since we have not found any sparticles, SUSY is broken.
There are many ways of breaking SUSY.
FYTN04: BSM 23 Leif Lönnblad Lund University
Grand UnificationˆSupersymmetry
(Super) String Theory
New particlesR-parity
ˇFine-tuning solved?
In the simplest version of SUSY (MSSM) we can derive massrelations for the Higgs particles, and get mh < mZ < mH .
But there are many ways of constructing SUSY.
If SUSY was an exact theory we would have mq = mq and itwould be easy to find the new particles.
Since we have not found any sparticles, SUSY is broken.
There are many ways of breaking SUSY.
FYTN04: BSM 23 Leif Lönnblad Lund University
Grand UnificationˆSupersymmetry
(Super) String Theory
New particlesR-parity
ˇFine-tuning solved?
R-parity
We can define a “parity” relating to SYSU, called R-parity
R = (−1)L+3B+2S
where L is lepton number, B is baryon number and S is spin.
All ordinary particles have R = +1 and their super-partnershave R = −1.
If R-parity is conserved, sparticles can only be produced inpairs.
This also means that the lightest super-symmetric particle(LSP) is stable.
FYTN04: BSM 24 Leif Lönnblad Lund University
Grand UnificationˆSupersymmetry
(Super) String Theory
New particlesR-parity
ˇFine-tuning solved?
Even if the masses are not the same, the couplings do not careif we have particles or sparticles. Hence we have that verticessuch as eg.
W + → e+νe, W + → e+νe, W + → e+νe, W + → e+νe
all have the same coupling (g2). So as soon as we come abovethe mass-threshold for producing sparticles, they will beproduced at the same rate as their ordinary particle equivalents.
FYTN04: BSM 25 Leif Lönnblad Lund University
Grand UnificationˆSupersymmetry
(Super) String Theory
ˆ R-parityFine-tuning solved?
The Higgs mass revisited
m2h(mZ ) ∼ m2
h(Λ)− (Λ2 −m2t )
With SUSY the Higgs would also have self-energy loops fromstop squarks (t), but since they are bosons, the sign of the loopis reversed
m2h(mZ ) ∼ m2
h(Λ)− (Λ2−m2t ) + (Λ2−m2
t ) ∼ m2h(Λ)− (m2
t −m2t )
So, as long as mt is not too large the fine-tuning goes away.
FYTN04: BSM 26 Leif Lönnblad Lund University
Grand UnificationˆSupersymmetry
(Super) String Theory
ˆ R-parityFine-tuning solved?
A dark matter candidate
If there is a stable LSP, which only interacts weakly (eg. χ0) itwould be produced copiously at the big bang and wouldbasically still be around.
Even if R-parity is not conserved and we could have decays likeγ → νγ, it could still contribute to dark matter if the decay isslow enough.
If R-parity is not conserved we could get lepton and/or baryonnumber violation (and proton decay).
FYTN04: BSM 27 Leif Lönnblad Lund University
Grand UnificationˆSupersymmetry
(Super) String Theory
ˆ R-parityFine-tuning solved?
Desperately seeking SUSY
With R-parity conserved we would get characteristic decaychains of sparticles according to their mass hierarchy., eg.
u → d + [χ+1 → ντ + [τ+ → τ+χ0
1]]
Should be easy to see at the LHC
(not seen yet)
FYTN04: BSM 28 Leif Lönnblad Lund University
Grand UnificationˆSupersymmetry
(Super) String Theory
ˆ R-parityFine-tuning solved?
Desperately seeking SUSY
With R-parity conserved we would get characteristic decaychains of sparticles according to their mass hierarchy., eg.
u → d + [χ+1 → ντ + [τ+ → τ+χ0
1]]
Should be easy to see at the LHC
(not seen yet)
FYTN04: BSM 28 Leif Lönnblad Lund University
Grand UnificationˆSupersymmetry
(Super) String Theory
ˆ R-parityFine-tuning solved?
The trouble with SUSY
I (more than) double number of particlesI (more than) double number of massesI (more than) double number of mixing angles
In total more than 100 free parameters to measure
FYTN04: BSM 29 Leif Lönnblad Lund University
Grand UnificationˆSupersymmetry
(Super) String Theory
StringsExtra dimensions
ˇLarge extra dimensions
A quantum theory of gravity
How do we include gravity in the standard model?
The naive way is to take General Relativity and reinterpret it asa Lagrange density
This leads to a spin-2 graviton (possibly with a supersymmetricspin 3/2 graviton) and a theory that is not renormalisable.
This is related to the fact that Field theory assumes particles tobe point-like.
FYTN04: BSM 30 Leif Lönnblad Lund University
Grand UnificationˆSupersymmetry
(Super) String Theory
StringsExtra dimensions
ˇLarge extra dimensions
(Super) String theory
Elementary particles are not point-like but vibration modes ofone-dimensional objects – Strings.
I a point like particles describes a world line, xµ(τ)
I a string will describe a world sheet, xµ(τ, σ)
A string can be open or closed (xµ(τ, σ + 2π) = xµ(τ, σ)).
FYTN04: BSM 31 Leif Lönnblad Lund University
Grand UnificationˆSupersymmetry
(Super) String Theory
StringsExtra dimensions
ˇLarge extra dimensions
Since nothing is point-like there is a natural cutoff to ensurerenormalisability.
FYTN04: BSM 32 Leif Lönnblad Lund University
Grand UnificationˆSupersymmetry
(Super) String Theory
StringsExtra dimensions
ˇLarge extra dimensions
To combine string theory with QFT is tricky
I To avoid tachyons (m2 < 0) we need 26 space-timedimensions.
I Including SUSY we can get down to 10 if we have SO(32)or E8 × E8 symmetry.
I Good news (1):E8 ⊃ E6 ⊃ SO(10) ⊃ SU(5) ⊃ SU(3)× SU(2)× U(1)but a new zoo of particles only interacting with gravity
I Good news (2): Ony five such theories: type-I, type-IIA,type-IIB, heterotic SO(32) and heterotic E8 × E8
I Good news (3)? Only special cases of 11-dimensionalM-theory, with ∼ 10500 different string theories consistentwith (SuSY) SM.
FYTN04: BSM 33 Leif Lönnblad Lund University
Grand UnificationˆSupersymmetry
(Super) String Theory
StringsExtra dimensions
ˇLarge extra dimensions
To combine string theory with QFT is tricky
I To avoid tachyons (m2 < 0) we need 26 space-timedimensions.
I Including SUSY we can get down to 10 if we have SO(32)or E8 × E8 symmetry.
I Good news (1):E8 ⊃ E6 ⊃ SO(10) ⊃ SU(5) ⊃ SU(3)× SU(2)× U(1)but a new zoo of particles only interacting with gravity
I Good news (2): Ony five such theories: type-I, type-IIA,type-IIB, heterotic SO(32) and heterotic E8 × E8
I Good news (3)? Only special cases of 11-dimensionalM-theory, with ∼ 10500 different string theories consistentwith (SuSY) SM.
FYTN04: BSM 33 Leif Lönnblad Lund University
Grand UnificationˆSupersymmetry
(Super) String Theory
StringsExtra dimensions
ˇLarge extra dimensions
To combine string theory with QFT is tricky
I To avoid tachyons (m2 < 0) we need 26 space-timedimensions.
I Including SUSY we can get down to 10 if we have SO(32)or E8 × E8 symmetry.
I Good news (1):E8 ⊃ E6 ⊃ SO(10) ⊃ SU(5) ⊃ SU(3)× SU(2)× U(1)but a new zoo of particles only interacting with gravity
I Good news (2): Ony five such theories: type-I, type-IIA,type-IIB, heterotic SO(32) and heterotic E8 × E8
I Good news (3)? Only special cases of 11-dimensionalM-theory, with ∼ 10500 different string theories consistentwith (SuSY) SM.
FYTN04: BSM 33 Leif Lönnblad Lund University
Grand UnificationˆSupersymmetry
(Super) String Theory
StringsExtra dimensions
ˇLarge extra dimensions
To combine string theory with QFT is tricky
I To avoid tachyons (m2 < 0) we need 26 space-timedimensions.
I Including SUSY we can get down to 10 if we have SO(32)or E8 × E8 symmetry.
I Good news (1):E8 ⊃ E6 ⊃ SO(10) ⊃ SU(5) ⊃ SU(3)× SU(2)× U(1)but a new zoo of particles only interacting with gravity
I Good news (2): Ony five such theories: type-I, type-IIA,type-IIB, heterotic SO(32) and heterotic E8 × E8
I Good news (3)? Only special cases of 11-dimensionalM-theory, with ∼ 10500 different string theories consistentwith (SuSY) SM.
FYTN04: BSM 33 Leif Lönnblad Lund University
Grand UnificationˆSupersymmetry
(Super) String Theory
StringsExtra dimensions
ˇLarge extra dimensions
Where are all the extra dimensions?
The universe extends only L ∼ m−1Pl in all but four dimensions –
compactification.
Have we checked that there are only four dimensions?
Current limit is L . 1µm.
FYTN04: BSM 34 Leif Lönnblad Lund University
Grand UnificationˆSupersymmetry
(Super) String Theory
ˆ Extra dimensionsLarge extra dimensions
How do we check the number of dimensions?
Look at the gravitational potential in 4 + n dimensions
V (r) ∼ mmn+2
Pl
1rn+1 ,
Now, if the n extra dimensions are of size R, for distances muchlarger than that the potential would look like
V (r) ∼ mmn+2
Pl
1Rn
1r
FYTN04: BSM 35 Leif Lönnblad Lund University
Grand UnificationˆSupersymmetry
(Super) String Theory
ˆ Extra dimensionsLarge extra dimensions
we have found mPl4 ≈ 1019 GeV. But if the extra dimensions arelarge this means that the true Planck scale is much smaller
mPl ∼ R−n
n+2 m2
n+2Pl4
could even be close to the scales reachable at the LHC.
FYTN04: BSM 36 Leif Lönnblad Lund University
Grand UnificationˆSupersymmetry
(Super) String Theory
ˆ Extra dimensionsLarge extra dimensions
FYTN04: BSM 37 Leif Lönnblad Lund University
Grand UnificationˆSupersymmetry
(Super) String Theory
ˆ Extra dimensionsLarge extra dimensions
BSM phenomenology
1. Make stuff up2. Check that it is consistent with the SM3. Make prediction (for the LHC)4. Convince the experiments to look for it5.
FYTN04: BSM 38 Leif Lönnblad Lund University
Grand UnificationˆSupersymmetry
(Super) String Theory
ˆ Extra dimensionsLarge extra dimensions
BSM phenomenology
1. Make stuff up2. Check that it is consistent with the SM3. Make prediction (for the LHC)4. Convince the experiments to look for it5.
FYTN04: BSM 38 Leif Lönnblad Lund University
Grand UnificationˆSupersymmetry
(Super) String Theory
ˆ Extra dimensionsLarge extra dimensions
BSM phenomenology
1. Make stuff up2. Check that it is consistent with the SM3. Make prediction (for the LHC)4. Convince the experiments to look for it5.
FYTN04: BSM 38 Leif Lönnblad Lund University
Grand UnificationˆSupersymmetry
(Super) String Theory
ˆ Extra dimensionsLarge extra dimensions
BSM phenomenology
1. Make stuff up2. Check that it is consistent with the SM3. Make prediction (for the LHC)4. Convince the experiments to look for it5.
FYTN04: BSM 38 Leif Lönnblad Lund University
Grand UnificationˆSupersymmetry
(Super) String Theory
ˆ Extra dimensionsLarge extra dimensions
BSM phenomenology
1. Make stuff up2. Check that it is consistent with the SM3. Make prediction (for the LHC)4. Convince the experiments to look for it5. Go to Stockholm and collect prize
FYTN04: BSM 38 Leif Lönnblad Lund University
Grand UnificationˆSupersymmetry
(Super) String Theory
ˆ Extra dimensionsLarge extra dimensions
BSM phenomenology
1. Make stuff up2. Check that it is consistent with the SM3. Make prediction (for the LHC)4. Convince the experiments to look for it5. When they find nothing, goto 1.
FYTN04: BSM 38 Leif Lönnblad Lund University