A bottom-up reconstruction of new physics at Large Hadron ...theory.tifr.res.in/Research/Seminars/Ritesh_TIFR.pdf · A bottom-up reconstruction of new physics at Large Hadron Collider

The Standard ModelBeyond the Standard ModelNew physics with top quarkSearch for Extra-dimensions

Conclusions

A bottom-up reconstruction of new physics atLarge Hadron Collider

Ritesh K. Singh

Institut fur Theoretische Physik und AstrophysikUniversitat Wurzburg

at

Tata Institute of Fundamental ResearchMumbai, January 13, 2010

Ritesh Singh New physics at LHC


Conclusions

1 The Standard ModelBuilding blockThe particles and forces

2 Beyond the Standard ModelThe approachNew physicsNew particles

3 New physics with top quarkTop quark at the edgeTop polarizationTop polarization measurement

4 Search for Extra-dimensionsFeatures of the extra-dimensionFlat extra-dimension at LHCWarped extra-dimension at LHC

5 Conclusions



Conclusions

Building blockThe particles and forces

The Standard Model



Conclusions


Sub-atomic world

It was long believed that matter is made of atoms and by mid 19thcentury it was an established fact.

By early 20th century we started to probe the Sub-atomic world.

Nucleus was identified in 1911.

Particle list:

1932: e, p, n were the fundamental building blocks.

1950: e, p, n, µ, νe , νµ, π±, π0,K 0,K± etc.

So many of particle cannot be fundamental.

+Certain pattern emerged among the zoo of particles.

⇒ These particle must be build of something else.



Conclusions


Sub-atomic world




Particle list:








Conclusions


Sub-atomic world




Particle list:








Conclusions


Sub-atomic world




Particle list:








Conclusions


Sub-atomic world




Particle list:








Conclusions


Sub-atomic world




Particle list:








Conclusions


Sub-atomic world




Particle list:








Conclusions


Sub-atomic world




Particle list:








Conclusions


The quark model

The matter particles were divide in two groups:

Hadrons: p, n, π±, π0,K± etc. particles that can interact strongly.

Leptons: e, νe , µ, νµ, τ , etc. particles that cannot interact strongly.

Leptons

are fundamental particles

interact only throughelectromagnetic and weakinteractions.

can be seen in free state.

justthe white space

Hadrons

are not fundamental particles

interact through strong weakand electromagneticinteractions.

are bound states of quarks thatcannot be seen in free state.

Quarks carry color quantum number and fractional electriccharges. (bottom-up)



Conclusions


The quark model




Leptons




justthe white space

Hadrons







Conclusions


The quark model




Leptons




justthe white space

Hadrons







Conclusions


The quark model




Leptons




justthe white space

Hadrons







Conclusions


Stucture of the Standard Model

Gravity not included.

Gauge groups:SU(3)c × SU(2)L × U(1)Y

Additional particle: Higgs boson

SU(3)c singletSU(2)L doubletY = 1

Leads to masses of the particles viaspontaneous symmetry breaking.(top-down)

Describes almost all observed phenomenon



Conclusions











Conclusions











Conclusions











Conclusions











Conclusions

The approachNew physicsNew particles

Beyond the Standard Model



Conclusions


Bottom-up vs Top-down

Top-down

Symmetry: gauge symmetry,space time symmetry etc.

Matter content: fermions,scalars and their quantumnumber under symmetries ⇒Lagrangian.

Self consistancy of Lagrangian:gauge anomaly etc.

Mechanisms: spontaneoussymmetry breaking, phasetransitions etc.

Predictions for experiments.

Bottom-up

Observables: σ, asymmetries,correlations etc.

Particle content: observed orrequired to explainobservations.

Quantum number: ad hocassignments to explainobservations.

Possible patterns in theparticles and their quantumnumbers ⇒ Symmetry.

Lagrangian



Conclusions



Top-down






Bottom-up





Lagrangian



Conclusions



Top-down






Bottom-up





Lagrangian



Conclusions



Top-down






Bottom-up





Lagrangian



Conclusions



Top-down






Bottom-up





Lagrangian



Conclusions



Top-down






Bottom-up





Lagrangian



Conclusions



Top-down






Bottom-up





Lagrangian



Conclusions



Top-down






Bottom-up





Lagrangian



Conclusions



Top-down






Bottom-up





Lagrangian



Conclusions



Top-down






Bottom-up





Lagrangian



Conclusions



Top-down






Bottom-up





Lagrangian



Conclusions


An example of top-quark

Top-down

Mass: Heavy

Charge: +2/3

Color Quantum number: 3

Iso-spin: +1/2

Hypercharge: +1

Spin : 1/2

Decay modes:t → b W +

t → b H+

t → c Z 0 etc.

Bottom-up

Mass: 173.1± 1.3 GeV

Charge: not +4/3 at 95% C.L.


Iso-spin: +1/2

Hypercharge: +1 ???

Spin : possibly 1/2


t → b H+

t → c Z 0 (Br < 0.1)



Conclusions



Top-down

Mass: Heavy

Charge: +2/3


Iso-spin: +1/2

Hypercharge: +1

Spin : 1/2


t → b H+

t → c Z 0 etc.

Bottom-up

Mass: 173.1± 1.3 GeV



Iso-spin: +1/2

Hypercharge: +1 ???

Spin : possibly 1/2


t → b H+

t → c Z 0 (Br < 0.1)



Conclusions



Top-down

Mass: Heavy

Charge: +2/3


Iso-spin: +1/2

Hypercharge: +1

Spin : 1/2


t → b H+

t → c Z 0 etc.

Bottom-up

Mass: 173.1± 1.3 GeV



Iso-spin: +1/2

Hypercharge: +1 ???

Spin : possibly 1/2


t → b H+

t → c Z 0 (Br < 0.1)



Conclusions



Top-down

Mass: Heavy

Charge: +2/3


Iso-spin: +1/2

Hypercharge: +1

Spin : 1/2


t → b H+

t → c Z 0 etc.

Bottom-up

Mass: 173.1± 1.3 GeV



Iso-spin: +1/2

Hypercharge: +1 ???

Spin : possibly 1/2


t → b H+

t → c Z 0 (Br < 0.1)



Conclusions



Top-down

Mass: Heavy

Charge: +2/3


Iso-spin: +1/2

Hypercharge: +1

Spin : 1/2


t → b H+

t → c Z 0 etc.

Bottom-up

Mass: 173.1± 1.3 GeV



Iso-spin: +1/2

Hypercharge: +1 ???

Spin : possibly 1/2


t → b H+

t → c Z 0 (Br < 0.1)



Conclusions



Top-down

Mass: Heavy

Charge: +2/3


Iso-spin: +1/2

Hypercharge: +1

Spin : 1/2


t → b H+

t → c Z 0 etc.

Bottom-up

Mass: 173.1± 1.3 GeV



Iso-spin: +1/2

Hypercharge: +1 ???

Spin : possibly 1/2


t → b H+

t → c Z 0 (Br < 0.1)



Conclusions



Top-down

Mass: Heavy

Charge: +2/3


Iso-spin: +1/2

Hypercharge: +1

Spin : 1/2


t → b H+

t → c Z 0 etc.

Bottom-up

Mass: 173.1± 1.3 GeV



Iso-spin: +1/2

Hypercharge: +1 ???

Spin : possibly 1/2


t → b H+

t → c Z 0 (Br < 0.1)



Conclusions



Top-down

Mass: Heavy

Charge: +2/3


Iso-spin: +1/2

Hypercharge: +1

Spin : 1/2


t → b H+

t → c Z 0 etc.

Bottom-up

Mass: 173.1± 1.3 GeV



Iso-spin: +1/2

Hypercharge: +1 ???

Spin : possibly 1/2


t → b H+

t → c Z 0 (Br < 0.1)



Conclusions


From Standard to New physics

The Standard Model has been tested to a high accuracy, but it still lacks

an experimental test of spontaneous symmetry breakingphenomenon or discovery of Higgs boson,

radiative stability of Higgs boson mass,

hierarchy of scales, electro-weak vs Planck scale,

first principle understanding of CP violation,

hierarchy of Yukawa couplings (fermion masses).

neutrino masses

dark matter candidate

Many solution to the theoretical issues are proposed:

SUSY

Scale hierarchy

Fermion massScale hierarchy

Extra Dim

CP violationFermion massScale hierarchy

Techni Color


Little Higgs




Conclusions









neutrino masses



SUSY

Scale hierarchy


Extra Dim


Techni Color


Little Higgs




Conclusions









neutrino masses



SUSY

Scale hierarchy


Extra Dim


Techni Color


Little Higgs




Conclusions









neutrino masses



SUSY

Scale hierarchy


Extra Dim


Techni Color


Little Higgs




Conclusions









neutrino masses



SUSY

Scale hierarchy


Extra Dim


Techni Color


Little Higgs




Conclusions









neutrino masses



SUSY

Scale hierarchy


Extra Dim


Techni Color


Little Higgs




Conclusions









neutrino masses



SUSY

Scale hierarchy


Extra Dim


Techni Color


Little Higgs




Conclusions









neutrino masses



SUSY

Scale hierarchy


Extra Dim


Techni Color


Little Higgs




Conclusions









neutrino masses



SUSY

Scale hierarchy


Extra Dim


Techni Color


Little Higgs




Conclusions









neutrino masses



SUSY

Scale hierarchy


Extra Dim


Techni Color


Little Higgs




Conclusions









neutrino masses



SUSY

Scale hierarchy


Extra Dim


Techni Color


Little Higgs




Conclusions









neutrino masses



SUSY

Scale hierarchy


Extra Dim


Techni Color


Little Higgs




Conclusions


New particles

All new physics models introduce new symmetries and particles.

Scalars

Higgs, sfermions,techni-pions etc.

Productions :s-channel resonance,pair production,associated production

Signature :threshold behaviour,polarization, 2-bodydecay, cascade decay.

Fermions

gaugino, higgsino,heavy fermion partners.

Productions :pair production,associated production.

s-channel resonance


Vectors

KK-excitations of gaugebosons, heavy bosons.


Signature :polarization, 2-bodydecay, cascade decay.

s-channel resonance

Polarization observables and decay pattern are most importantfeatures to study new particles.



Conclusions


New particles


Scalars




Fermions



s-channel resonance


Vectors




s-channel resonance




Conclusions


New particles


Scalars




Fermions



s-channel resonance


Vectors




s-channel resonance




Conclusions


New particles


Scalars




Fermions



s-channel resonance


Vectors




s-channel resonance




Conclusions


New particles


Scalars




Fermions



s-channel resonance


Vectors




s-channel resonance




Conclusions


New particles


Scalars




Fermions



s-channel resonance


Vectors




s-channel resonance




Conclusions


New particles


Scalars




Fermions



s-channel resonance


Vectors




s-channel resonance




Conclusions


New particles


Scalars




Fermions



s-channel resonance


Vectors




s-channel resonance




Conclusions


New particles


Scalars




Fermions



s-channel resonance


Vectors




s-channel resonance




Conclusions


New particles


Scalars




Fermions



s-channel resonance


Vectors




s-channel resonance




Conclusions


New particles


Scalars




Fermions



s-channel resonance


Vectors




s-channel resonance




Conclusions

Top quark at the edgeTop polarizationTop polarization measurement

New physics with top quark



Conclusions


Top quark: A looking glass

The mass of the top-quark is very large (mt ∼ 173GeV)

top-mass being close to electro-weak scale, its couplings are sensitiveto EWSB. Any new physics of EWSB (or mass generation) affectstop-couplings with other particles.

its decay width (Γt ∼ 1.5 GeV) is much larger than the typical scaleof hadronization, i.e. it decays before getting hadronized. The spininformation of top-quark is translated to the decay distribution.

the decay lepton angular distribution is insensitive to the anomaloustbW couplings, and hence a pure probe of new physics intop-production process; observed for top-pair production at e+e−

(Rindani, Grzadkowski) as well as γγ collider (Ohkuma,Godbole).

leptons from top decay provide a clean and un-contaminatedprobe of top-production mechanism.

We have a clean looking glass for new physics.



Conclusions












Conclusions












Conclusions












Conclusions












Conclusions












Conclusions


Anomalous top decay JHEP 0612, 021 (2006), [hep-ph/0605100]

Anomalous tbW vertex :

Γµ =g√2

[γµ(f1LPL + f1RPR)− iσµν

mW(pt − pb)ν (f2LPL + f2RPR)

]

In the SM, f1L = 1, f1R = 0, f2L = 0, f2R = 0.

Contribution from f1R , f2L are proportional to mb.

1

Γt

dΓt

d cos θf=

1

2

(1 + αf Pt cos θf

)αl = 1−O(f 2

i )

αb = −[m2

t − 2m2W

m2t + 2m2

W

]+ <(f2R)

[8mtmW (m2

t −m2W )

(m2t + 2m2

W )2

]+O

(mb

mW, f 2

i

)



Conclusions




Γµ =g√2



]



1

Γt

dΓt

d cos θf=

1

2

(1 + αf Pt cos θf

)αl = 1−O(f 2

i )

αb = −[m2

t − 2m2W

m2t + 2m2

W

]+ <(f2R)

[8mtmW (m2

t −m2W )

(m2t + 2m2

W )2

]+O

(mb

mW, f 2

i

)



Conclusions




Γµ =g√2



]



1

Γt

dΓt

d cos θf=

1

2

(1 + αf Pt cos θf

)αl = 1−O(f 2

i )

αb = −[m2

t − 2m2W

m2t + 2m2

W

]+ <(f2R)

[8mtmW (m2

t −m2W )

(m2t + 2m2

W )2

]+O

(mb

mW, f 2

i

)



Conclusions


Lepton distribution JHEP 0612, 021 (2006), [hep-ph/0605100]

AB t P1 ... Pn−1

b W+

l+ ν

Lepton distribution is independent of anomalous tbW coupling if

t-quark is on-shell; narrow-width approximation for t-quark,

anomalous couplings f1R , f2R and f2L are small,

narrow-width approximation for W -boson,

b-quark is mass-less,

t → bW (`ν`) is the only decay channel for t-quark.

⇒ Lepton distribution from top decay is pure probe of possiblenew physics in the top production process.



Conclusions



AB t P1 ... Pn−1

b W+

l+ ν










Conclusions



AB t P1 ... Pn−1

b W+

l+ ν










Conclusions



AB t P1 ... Pn−1

b W+

l+ ν










Conclusions



AB t P1 ... Pn−1

b W+

l+ ν










Conclusions



AB t P1 ... Pn−1

b W+

l+ ν










Conclusions



AB t P1 ... Pn−1

b W+

l+ ν










Conclusions



AB t P1 ... Pn−1

b W+

l+ ν










Conclusions


Polarization or t-quark: top-down JHEP 0612, 021 (2006), [hep-ph/0605100]

Polarized cross-sections

σ(λ, λ′) =

Z d3pt

2Et (2π)3

0@n−1Yi=1

d3pi

2Ei (2π)3

1A (2π)4

2Iδ

4

0@kA + kB − pt −

0@n−1Xi=1

pi

1A1A ρ(λ, λ′)

where ρ(λ, λ′) = M(λ, ...)M∗(λ′, ...)

Total cross-section: σtot = σ(+,+) + σ(−,−)

Polarization density matrix :

Pt =1

2

(1 + η3 η1 − iη2

η1 + iη2 1− η3

),

η3 = (σ(+,+)− σ(−,−)) /σtot

η1 = (σ(+,−) + σ(−,+)) /σtot

i η2 = (σ(+,−)− σ(−,+)) /σtot



Conclusions




σ(λ, λ′) =

Z d3pt

2Et (2π)3

0@n−1Yi=1

d3pi

2Ei (2π)3

1A (2π)4

2Iδ

4

0@kA + kB − pt −

0@n−1Xi=1

pi

1A1A ρ(λ, λ′)

where ρ(λ, λ′) = M(λ, ...)M∗(λ′, ...)



Pt =1

2

(1 + η3 η1 − iη2

η1 + iη2 1− η3

),

η3 = (σ(+,+)− σ(−,−)) /σtot

η1 = (σ(+,−) + σ(−,+)) /σtot

i η2 = (σ(+,−)− σ(−,+)) /σtot



Conclusions




σ(λ, λ′) =

Z d3pt

2Et (2π)3

0@n−1Yi=1

d3pi

2Ei (2π)3

1A (2π)4

2Iδ

4

0@kA + kB − pt −

0@n−1Xi=1

pi

1A1A ρ(λ, λ′)

where ρ(λ, λ′) = M(λ, ...)M∗(λ′, ...)



Pt =1

2

(1 + η3 η1 − iη2

η1 + iη2 1− η3

),

η3 = (σ(+,+)− σ(−,−)) /σtot

η1 = (σ(+,−) + σ(−,+)) /σtot

i η2 = (σ(+,−)− σ(−,+)) /σtot



Conclusions


Polarization or t-quark: bottom-up JHEP 0612, 021 (2006), [hep-ph/0605100]

Polarization of t-quark through decay asymmetries:

αb = −0.4

αl = +1.0

αfη3

2=

σ(pf .s3 < 0)− σ(pf .s3 > 0)

σ(pf .s3 < 0) + σ(pf .s3 > 0)

αfη2

2=

σ(pf .s2 < 0)− σ(pf .s2 > 0)

σ(pf .s2 < 0) + σ(pf .s2 > 0)

αfη1

2=

σ(pf .s1 < 0)− σ(pf .s1 > 0)

σ(pf .s1 < 0) + σ(pf .s1 > 0)

si .sj = −δij pt .si = 0

For pµt = Et(1, βt sin θt , 0, βt cos θt), we have

sµ1 = (0,− cos θt , 0, sin θt), sµ2 = (0, 0, 1, 0), sµ3 = Et(βt , sin θt , 0, cos θt)/mt .

Ptlong is implemented in SHERPA.



Conclusions


Lepton’s azimuthal distribution JHEP 0612, 021 (2006), [hep-ph/0605100]

Lab frame azimuthal distribution of leptons:

0

0.005

0.01

0.015

0.02

0.025

0.03

0.035

0.04

0.045

0.05

0.055

0 1 2 3 4 5 6

(1/σ

) dσ

/dφ l

[ra

d-1]

φl [rad]

η3 = +0.83η3 = -0.83η3 = +0.73η3 = -0.48

A` =σ(cosφl > 0) − σ(cosφl < 0)

σ(cosφl > 0) + σ(cosφl < 0)

Used for:

Z′ at LHC (Les Houches 05)

g(1) in RS model at LHC(Nucl. Phys. B797, 1, (2008))



Conclusions




0.93

0.94

0.95

0.96

0.97

0.98

0.99

1

2 2.2 2.4 2.6 2.8 3 3.2 3.4 3.6 3.8 4

Al(m

tt)

mtt [ x 103 GeV]

[ p p → t t ]

E1

SMSM + RS

A` =σ(cosφl > 0) − σ(cosφl < 0)

σ(cosφl > 0) + σ(cosφl < 0)

Used for:

Z′ at LHC (Les Houches 05)

g(1) in RS model at LHC(Nucl. Phys. B797, 1, (2008))



Conclusions




0

0.5

1

1.5

2

2.5

3

3.5

4

0 π/2 π 3π/2 2π

2π/σ

dσ/

dφ

φ (rad)

Pp = ( 0.8,-0.6)η3 = +0.559, η1 = -0.504

lνb

Distribution of all the decayparticles.



Conclusions


Top polarization at LHC Boudjema, Porod and RS: Under progress

pp → tj → bl+νl j

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0 π/4 π/2 3π/4 π

(1/σ

) dσ

/dΦ

Φ

Leptonb-quark

0

2

4

6

8

10

12

14

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

(1/

σ) d

σ/dp

tT [

TeV

-1]

ptT [TeV]

∆lb =1

σ

∣∣∣∣ dσ

dφl− dσ

dφb

∣∣∣∣Depends upon:• Top polarization• pT

t distribution

σ = 131 pb η3 = −0.196∆lb = 0.35

Cuts: No cuts

Model: SM

Mg = 3TeV,Γg = 500 GeV Mg = 3TeV,Γg = 500 GeV



Conclusions



pp → t1¯t1 → tχ0

1tχ01

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 π/4 π/2 3π/4 π

(1/σ

) dσ

/dΦ

Φ

Leptonb-quark

0

1

2

3

4

5

6

7

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

(1/

σ) d

σ/dp

tT [

TeV

-1]

ptT [TeV]

∆lb =1

σ

∣∣∣∣ dσ

dφl− dσ

dφb


t distribution

σ = 1.44 fb η3 = +0.184∆lb = 0.12

Cuts: No cuts

Model: MSSMMt1

= 355 GeV, mχ = 164GeV Br(t1 → tχ0

1) = 0.76



Conclusions



pp → tt → bl+νl bl−νl

0

1

2

3

4

5

6

7

0 π/4 π/2 3π/4 π

(1/σ

) dσ

/dΦ

Φ

Leptonb-quark

0

0.2

0.4

0.6

0.8

1

1.2

1.4

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8

(1/

σ) d

σ/dp

tT [

TeV

-1]

ptT [TeV]

∆lb =1

σ

∣∣∣∣ dσ

dφl− dσ

dφb


t distribution

σ = 3.36 pb η3 = +0.819∆lb = 0.40

Cuts: mtt ∈ [2.5, 3.5] TeV

Model: SM+g (1)

Mg = 3TeV, Γg = 500 GeV

Mg = 3TeV, Γg = 500 GeV



Conclusions

Features of the extra-dimensionFlat extra-dimension at LHCWarped extra-dimension at LHC

Search for Extra-dimensions



Conclusions


World with extra-dimesions

In models with extra space dimensions, the additional dimensions arecompact.

Particle in a box

Compact extra dim

⇒ Infinite potential well

⇒

or Particle in a box

⇒ Infinite tower of

⇒

equi-spaced (R−1) states

Mass spectrum of photon:0, (R−1) GeV, 2(R−1) Gev, ...

Near-degenerate spectrum

All partilcles have infinite towerof states.

We have γ(1), Z (1), g (1), t(1)

etc. at nearly the same mass(R−1) Gev.

Several particles with same QNas in SM and large (R−1) butnear-degenerate mass.



Conclusions




Particle in a box

Compact extra dim


⇒



⇒





We have γ(1), Z (1), g (1), t(1)





Conclusions




Particle in a box

Compact extra dim


⇒



⇒





We have γ(1), Z (1), g (1), t(1)





Conclusions




Particle in a box

Compact extra dim


⇒



⇒





We have γ(1), Z (1), g (1), t(1)





Conclusions




Particle in a box

Compact extra dim


⇒



⇒





We have γ(1), Z (1), g (1), t(1)





Conclusions




Particle in a box

Compact extra dim


⇒



⇒





We have γ(1), Z (1), g (1), t(1)





Conclusions




Particle in a box

Compact extra dim


⇒



⇒





We have γ(1), Z (1), g (1), t(1)





Conclusions




Particle in a box

Compact extra dim


⇒



⇒





We have γ(1), Z (1), g (1), t(1)





Conclusions




Particle in a box

Compact extra dim


⇒



⇒





We have γ(1), Z (1), g (1), t(1)





Conclusions


Flat extra-dimensions and top quarks Under progress

In the models of flat extra-dimensions, there is a KK-tower of excitationscorresponding to each SM gauge bosons and fermions.

The channel under study at the LHC:

qq → V → tt

V ≡ γ, Z , g , γ(1), Z (1), g (1)

The pure SM background:

gg → tt

All KK-excitations contribute to a resonance in mtt distribution. Thepresence of Z and Z (1) is responsible for finite polarization of top quark.



Conclusions





qq → V → tt

V ≡ γ, Z , g , γ(1), Z (1), g (1)


gg → tt




Conclusions





qq → V → tt

V ≡ γ, Z , g , γ(1), Z (1), g (1)


gg → tt




Conclusions





qq → V → tt

V ≡ γ, Z , g , γ(1), Z (1), g (1)


gg → tt




Conclusions





qq → V → tt

V ≡ γ, Z , g , γ(1), Z (1), g (1)


gg → tt




Conclusions



10-3 10-2 10-1 1 10 102 103

0 500 1000 1500 2000 2500 3000 3500 4000

dσ/d

mtt

[fb/

GeV

]

mtt [GeV]

1.0 TeV1.5 TeV2.0 TeV2.5 TeV3.0 TeV

SM

-0.06

-0.05

-0.04

-0.03

-0.02

-0.01

0

0 500 1000 1500 2000 2500 3000 3500 4000

P t(m

tt)

mtt [GeV]

1.0 TeV1.5 TeV2.0 TeV2.5 TeV3.0 TeV

SM



Conclusions



For MKK = 2 TeV, and |mtt −MKK | < 50 GeV,

Models σ(pp → tt) (fb) Pt

SM 77.9 −1.33× 10−3

SM + γ(1) 185 −2.55× 10−4

SM + Z (1) 150 −3.26× 10−1

SM + g (1) 1700 −6.13× 10−5

SM + VKK 1900 −5.78× 10−2



Conclusions



Weak resonance model, fi fiV := AV T fi3 + BV Q fi ; i = L,R

-3

-2.5

-2

-1.5

-1

-0.5

0

0.5

1

1.5

2

2.5

3

-3 -2.5 -2 -1.5 -1 -0.5 0 0.5 1 1.5 2 2.5 3

BV

AV

σW [fb]

220

220

210

200

200

180

160150

120100

-3

-2.5

-2

-1.5

-1

-0.5

0

0.5

1

1.5

2

2.5

3

-3 -2.5 -2 -1.5 -1 -0.5 0 0.5 1 1.5 2 2.5 3

BV

AV

PWt

0.5

0.5

0.4

0.40.3

0.3

0.2

0.2

0.1

0.1

0

0 -0.1

-0.1

-0.2

-0.2

-0.3

-0.3

-0.4

-0.4

-0.5

-0.5



Conclusions



Strong resonance model, f f V := RV PL + LV PL

-3

-2.5

-2

-1.5

-1

-0.5

0

0.5

1

1.5

2

2.5

3

-3 -2.5 -2 -1.5 -1 -0.5 0 0.5 1 1.5 2 2.5 3

RV

LV

σS [pb]

0.2

0.4

0.6

0.8

1.2

1.4

1.6

-3

-2.5

-2

-1.5

-1

-0.5

0

0.5

1

1.5

2

2.5

3

-3 -2.5 -2 -1.5 -1 -0.5 0 0.5 1 1.5 2 2.5 3

RV

LV

PSt

0.8

0.8

0.6

0.6

0.4

0.4

0.2

0.2

0

0

-0.2

-0.2

-0.4

-0.4

-0.6

-0.6

-0.8

-0.8



Conclusions


Warped extra-dimension and top quark Under progress

In universal wrapped extra dimension model, with fermion localization inthe fifth dimensions, one has differing couplings of VKK .

For electro weak boson:

fi fiV :=(AV T fi

3 + BV Q fi)

QV (fi ) ; i = L,R

For strong boson:

f f V := QV (fR) RV PR + QV (fL) LV PL

can explain fermion mass hierarchy,

can explain AbFB anomaly thourgh Z − Z

′(1) mixing,

can explain AtFB anomaly thourgh g (1) contribution at Tevatron,

can be probed at LHC upto MKK = 3 TeV through polarization.



Conclusions





fi fiV :=(AV T fi

3 + BV Q fi)

QV (fi ) ; i = L,R

For strong boson:




′(1) mixing,





Conclusions





fi fiV :=(AV T fi

3 + BV Q fi)

QV (fi ) ; i = L,R

For strong boson:




′(1) mixing,





Conclusions





fi fiV :=(AV T fi

3 + BV Q fi)

QV (fi ) ; i = L,R

For strong boson:




′(1) mixing,





Conclusions





fi fiV :=(AV T fi

3 + BV Q fi)

QV (fi ) ; i = L,R

For strong boson:




′(1) mixing,





Conclusions





fi fiV :=(AV T fi

3 + BV Q fi)

QV (fi ) ; i = L,R

For strong boson:




′(1) mixing,





Conclusions





fi fiV :=(AV T fi

3 + BV Q fi)

QV (fi ) ; i = L,R

For strong boson:




′(1) mixing,





Conclusions



0.001

0.01

0.1

1

2 2.2 2.4 2.6 2.8 3 3.2 3.4 3.6 3.8 4

dσ/d

mtt

[fb/

GeV

]

mtt [ x 103 GeV]

[ p p → t t ]

E1

SMSM + RSSM + g(1)

SM + γ(1)

SM + Z(1)

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

2 2.2 2.4 2.6 2.8 3 3.2 3.4 3.6 3.8 4

P t(m

tt)

mtt [ x 103 GeV]

[ p p → t t ]

E1

SMSM + E1

Γg (1) = 627 GeV, ΓZ (1) = 75 GeV, Γγ(1) = 137 GeV(Nucl. Phys. B797, 1, (2008))



Conclusions



In the case of warped extra-dimension:

there are too many free parameters for the fit.

the ”Weak resonance model” fails

the ”Strong resonance model” fits well with ”wrong” values of thecouplings.

more observables are needed to establish the presence ofextra-dimensions.



Conclusions

to conclude ....

There are many models of physics beyond the SM.

These models are expected to have significant signals at upcomingLHC.

Many of the models will have similar collider signature.

We need a model-independent i.e. a bottom-up approach to thesignatures to establish or rule out some models.



Conclusions

to conclude ....







Conclusions

to conclude ....







Conclusions

to conclude ....







Conclusions

to conclude ....







Conclusions

Beyond the conclusions....

Spin measurement using azimuthal distribution (arXiv:0903.4705)

Spin assesment in off-shell decays: A case of gluino (Under progress)

Markov-Chain-Monte-Carlo analysis of MSSM-UG models(arXiv:0906.5048)

MCMC analysis of CPV-MSSM and GHU-MSSM (Under progress)


Documents

A bottom-up reconstruction of new physics at Large Hadron ...theory.tifr.res.in/Research/Seminars/Ritesh_TIFR.pdf · A bottom-up reconstruction of new physics at Large Hadron Collider