new physics in single-top production at the large hadron...
TRANSCRIPT
New Physics inSingle-Top Productionat the Large Hadron
Collider
Pankaj Sharma
Korea Institute for
Advanced Study
Seoul
South Korea
Introduction
The Top Quark
Top couplings
Top Polarization
Single top with W−
Angular distribution
of ℓ+
Energy distribution of
ℓ+
CP violation insingle-top
Single top with H−
Top-polarization
Angular distribution
of ℓ+
Conclusions
New Physics in Single-Top Production at the LargeHadron Collider
Pankaj Sharma
Korea Institute for Advanced Study
Seoul
South Korea
16th April, 2013
New Physics inSingle-Top Productionat the Large Hadron
Collider
Pankaj Sharma
Korea Institute for
Advanced Study
Seoul
South Korea
Introduction
The Top Quark
Top couplings
Top Polarization
Single top with W−
Angular distribution
of ℓ+
Energy distribution of
ℓ+
CP violation insingle-top
Single top with H−
Top-polarization
Angular distribution
of ℓ+
Conclusions
This talk is based on following papers :
“Probing anomalous tbW couplings in single-top production
using top polarization at the Large Hadron Collider”
S. D. Rindani and P.S.arXiv:1107.2597 [hep-ph], JHEP 1111, 082 (2011)
“CP violation in tbW couplings at the LHC”
S. D. Rindani and P.S.arXiv:1108.4165 [hep-ph], Under Review in Phys. Rev. Lett.
“Probing top charged-Higgs production using top polarization
at the Large Hadron Collider”
K. Huitu, S. Kumar Rai, K. Rao, S. D. Rindani and P.S.arXiv:1012.0527 [hep-ph], JHEP 1104, 026 (2011)
New Physics inSingle-Top Productionat the Large Hadron
Collider
Pankaj Sharma
Korea Institute for
Advanced Study
Seoul
South Korea
Introduction
The Top Quark
Top couplings
Top Polarization
Single top with W−
Angular distribution
of ℓ+
Energy distribution of
ℓ+
CP violation insingle-top
Single top with H−
Top-polarization
Angular distribution
of ℓ+
Conclusions
PLAN
Introduction
⇒ The Top quark
⇒ Top-quark properties
⇒ Top-decay distribution
⇒ Top Polarization
Single-top production in association with a W .
CP-violation in single-top production.
top-charged Higgs associated production in 2HDM at LHC.
New Physics inSingle-Top Productionat the Large Hadron
Collider
Pankaj Sharma
Korea Institute for
Advanced Study
Seoul
South Korea
Introduction
The Top Quark
Top couplings
Top Polarization
Single top with W−
Angular distribution
of ℓ+
Energy distribution of
ℓ+
CP violation insingle-top
Single top with H−
Top-polarization
Angular distribution
of ℓ+
Conclusions
From Standard Model to New Physcis
All new physics models predict existance of new particles
Scalars : Higgs, sfermions etc.Signature : 2-body decay, cascade decay, polarization
Fermions : Gaugino, Higgsino, Heavy partners of fermions etc.Signature : cascade decay, polarization
Vectors : KK-excitations of gauge bosons, heavy bosons etc.Signature : 2-body decay, cascade decay, polarization
All these new particles have chiral couplings with the top quark.
⇒ Thus polarization observables are important to study new physics.
New Physics inSingle-Top Productionat the Large Hadron
Collider
Pankaj Sharma
Korea Institute for
Advanced Study
Seoul
South Korea
Introduction
The Top Quark
Top couplings
Top Polarization
Single top with W−
Angular distribution
of ℓ+
Energy distribution of
ℓ+
CP violation insingle-top
Single top with H−
Top-polarization
Angular distribution
of ℓ+
Conclusions
Top quark and New Physics
Top-quark couplings to SM particles are subjected to change dueto new particles and new interactions.
Using only Lorentz invariance, the tbW coupling can be written infollowing form:
Γµ =−g√2Vtb
[
γµ(f1LPL + f1RPR) − iσµν
mW
(pt − pb)ν(f2LPL + f2RPR)
]
In the SM, f1L = 1 and f1R = f2L = f2R = 0.
These form factors in SM extensions like LH, 2HDM, MSSM and(TC2) have been evaluated. [Bernreuther et al]
Bounds on f1R and f2L is stringent from B-physics.
f2R is very loosely contrained.
New Physics inSingle-Top Productionat the Large Hadron
Collider
Pankaj Sharma
Korea Institute for
Advanced Study
Seoul
South Korea
Introduction
The Top Quark
Top couplings
Top Polarization
Single top with W−
Angular distribution
of ℓ+
Energy distribution of
ℓ+
CP violation insingle-top
Single top with H−
Top-polarization
Angular distribution
of ℓ+
Conclusions
Top Quark Properties
Measurement SM prediction
Mass (173.2 ± 0.9) GeV1 -Charge Not 4/3(94% CL)2 2/3Spin - 1/2
⇒Need to know Top-quark properties precisely.
the heaviest fundamental particle discovered so far
Because of its large mass, its decay width is very large
Its life time is ∼ 5× 10−25s which is smaller than hadronizationscale ∼ 3× 10−24s
Thus polarization of a bare top quark is a measurable quantity.
1FERMILAB-TM-2504-E, arXiv:1107.52552DØ Note 4876-CONF
New Physics inSingle-Top Productionat the Large Hadron
Collider
Pankaj Sharma
Korea Institute for
Advanced Study
Seoul
South Korea
Introduction
The Top Quark
Top couplings
Top Polarization
Single top with W−
Angular distribution
of ℓ+
Energy distribution of
ℓ+
CP violation insingle-top
Single top with H−
Top-polarization
Angular distribution
of ℓ+
Conclusions
Top Polarization
In the top-rest frame, the distribution of its decay products is givenby
1
Γ
dΓf
d cos θf=
1
2(1 + κPt cos θf )
Pt is the top-polarization and is defined as
Pt =N↑ −N↓
N↑ +N↓
,
κ is known as the analysing power
The ℓ+ and d quark are the best spin analyzers with κℓ+ = κd = 1,
Thus the ℓ+ or d have the largest probability of being emitted inthe direction of the top spin,
New Physics inSingle-Top Productionat the Large Hadron
Collider
Pankaj Sharma
Korea Institute for
Advanced Study
Seoul
South Korea
Introduction
The Top Quark
Top couplings
Top Polarization
Single top with W−
Angular distribution
of ℓ+
Energy distribution of
ℓ+
CP violation insingle-top
Single top with H−
Top-polarization
Angular distribution
of ℓ+
Conclusions
Top Polarization Contd
A issue
These distributions are defined in top-quark rest frame.
Reconstruction of top-rest frame is difficult at LHC
Our Prescription
We study lab-frame distributions of top-decay products,
Decay-lepton angular distribution is insensitive of anomalous tbWcouplings at linear order,
New Physics inSingle-Top Productionat the Large Hadron
Collider
Pankaj Sharma
Korea Institute for
Advanced Study
Seoul
South Korea
Introduction
The Top Quark
Top couplings
Top Polarization
Single top with W−
Angular distribution
of ℓ+
Energy distribution of
ℓ+
CP violation insingle-top
Single top with H−
Top-polarization
Angular distribution
of ℓ+
Conclusions
Top Polarization Contd
A issue
These distributions are defined in top-quark rest frame.
Reconstruction of top-rest frame is difficult at LHC
Our Prescription
We study lab-frame distributions of top-decay products,
Decay-lepton angular distribution is insensitive of anomalous tbWcouplings at linear order,
Thus, we have a pure and clean looking glass for top polarization.
New Physics inSingle-Top Productionat the Large Hadron
Collider
Pankaj Sharma
Korea Institute for
Advanced Study
Seoul
South Korea
Introduction
The Top Quark
Top couplings
Top Polarization
Single top with W−
Angular distribution
of ℓ+
Energy distribution of
ℓ+
CP violation insingle-top
Single top with H−
Top-polarization
Angular distribution
of ℓ+
Conclusions
Top Polarization Contd
A issue
These distributions are defined in top-quark rest frame.
Reconstruction of top-rest frame is difficult at LHC
Our Prescription
We study lab-frame distributions of top-decay products,
Decay-lepton angular distribution is insensitive of anomalous tbWcouplings at linear order,
Thus, we have a pure and clean looking glass for top polarization.
⇒ New Physics
New Physics inSingle-Top Productionat the Large Hadron
Collider
Pankaj Sharma
Korea Institute for
Advanced Study
Seoul
South Korea
Introduction
The Top Quark
Top couplings
Top Polarization
Single top with W−
Angular distribution
of ℓ+
Energy distribution of
ℓ+
CP violation insingle-top
Single top with H−
Top-polarization
Angular distribution
of ℓ+
Conclusions
A generic top-production process
A B t P1 ... Pn−1
b W+
l+ ν
Lepton angular distributions are independent of anomalous tbWcouplings under following assumptions:
[Godbole, Rindani], [Grzadkowski]
New Physics inSingle-Top Productionat the Large Hadron
Collider
Pankaj Sharma
Korea Institute for
Advanced Study
Seoul
South Korea
Introduction
The Top Quark
Top couplings
Top Polarization
Single top with W−
Angular distribution
of ℓ+
Energy distribution of
ℓ+
CP violation insingle-top
Single top with H−
Top-polarization
Angular distribution
of ℓ+
Conclusions
A generic top-production process
A B t P1 ... Pn−1
b W+
l+ ν
Lepton angular distributions are independent of anomalous tbWcouplings under following assumptions:
[Godbole, Rindani], [Grzadkowski]
top is on-shell; narrow-width approximation for top,
|M|2 =πδ(p2t −m2
t )
Γtmt
∑
i,j
ρ(λ, λ′)Γ(λ, λ′)
where ρ(λ, λ′) = Mρ(λ)M∗ρ (λ
′).
New Physics inSingle-Top Productionat the Large Hadron
Collider
Pankaj Sharma
Korea Institute for
Advanced Study
Seoul
South Korea
Introduction
The Top Quark
Top couplings
Top Polarization
Single top with W−
Angular distribution
of ℓ+
Energy distribution of
ℓ+
CP violation insingle-top
Single top with H−
Top-polarization
Angular distribution
of ℓ+
Conclusions
A generic top-production process
A B t P1 ... Pn−1
b W+
l+ ν
Lepton angular distributions are independent of anomalous tbWcouplings under following assumptions:
[Godbole, Rindani], [Grzadkowski]
top is on-shell; narrow-width approximation for top,
|M|2 =πδ(p2t −m2
t )
Γtmt
∑
i,j
ρ(λ, λ′)Γ(λ, λ′)
where ρ(λ, λ′) = Mρ(λ)M∗ρ (λ
′).
couplings f1R, f2L and f2R are small,
New Physics inSingle-Top Productionat the Large Hadron
Collider
Pankaj Sharma
Korea Institute for
Advanced Study
Seoul
South Korea
Introduction
The Top Quark
Top couplings
Top Polarization
Single top with W−
Angular distribution
of ℓ+
Energy distribution of
ℓ+
CP violation insingle-top
Single top with H−
Top-polarization
Angular distribution
of ℓ+
Conclusions
A generic top-production process
A B t P1 ... Pn−1
b W+
l+ ν
Lepton angular distributions are independent of anomalous tbWcouplings under following assumptions:
[Godbole, Rindani], [Grzadkowski]
top is on-shell; narrow-width approximation for top,
|M|2 =πδ(p2t −m2
t )
Γtmt
∑
i,j
ρ(λ, λ′)Γ(λ, λ′)
where ρ(λ, λ′) = Mρ(λ)M∗ρ (λ
′).
couplings f1R, f2L and f2R are small,
t → bW (ℓνℓ) is the only decay channel,
New Physics inSingle-Top Productionat the Large Hadron
Collider
Pankaj Sharma
Korea Institute for
Advanced Study
Seoul
South Korea
Introduction
The Top Quark
Top couplings
Top Polarization
Single top with W−
Angular distribution
of ℓ+
Energy distribution of
ℓ+
CP violation insingle-top
Single top with H−
Top-polarization
Angular distribution
of ℓ+
Conclusions
Decay distribution
Using NWA for top quark, the decay distribution can be separated intoproduction and decay parts
dσ =∑
λ,λ′
[
(2π)4
2Iρ(λ, λ′)δ4
(
kA + kB − pt −n−1∑
i
pi
)
d3pt
2Et(2π)3
n−1∏
i
d3pi
2Ei(2π)3
]
×[
1
Γt
(2π)4
2mt
Γ(λ, λ′)δ4(pt − pb − pν − pℓ)d3pb
2Eb(2π)3d3pν
2Eν(2π)3d3pℓ
2Eℓ(2π)3
]
.
New Physics inSingle-Top Productionat the Large Hadron
Collider
Pankaj Sharma
Korea Institute for
Advanced Study
Seoul
South Korea
Introduction
The Top Quark
Top couplings
Top Polarization
Single top with W−
Angular distribution
of ℓ+
Energy distribution of
ℓ+
CP violation insingle-top
Single top with H−
Top-polarization
Angular distribution
of ℓ+
Conclusions
Decay distribution
Using NWA for top quark, the decay distribution can be separated intoproduction and decay parts
dσ =∑
λ,λ′
[
(2π)4
2Iρ(λ, λ′)δ4
(
kA + kB − pt −n−1∑
i
pi
)
d3pt
2Et(2π)3
n−1∏
i
d3pi
2Ei(2π)3
]
×[
1
Γt
(2π)4
2mt
Γ(λ, λ′)δ4(pt − pb − pν − pℓ)d3pb
2Eb(2π)3d3pν
2Eν(2π)3d3pℓ
2Eℓ(2π)3
]
.
Production part (φt = 0)
∫
d3pt
2Et(2π)3
n−1∏
i
d3pi
2Ei(2π)3(2π)4
2Iρ(λ, λ′)δ4
(
kA + kB − pt −n−1∑
i
pi
)
= dσ2→n(λ, λ′)dEtd cos θt
New Physics inSingle-Top Productionat the Large Hadron
Collider
Pankaj Sharma
Korea Institute for
Advanced Study
Seoul
South Korea
Introduction
The Top Quark
Top couplings
Top Polarization
Single top with W−
Angular distribution
of ℓ+
Energy distribution of
ℓ+
CP violation insingle-top
Single top with H−
Top-polarization
Angular distribution
of ℓ+
Conclusions
Decay distribution
Using NWA for top quark, the decay distribution can be separated intoproduction and decay parts
dσ =∑
λ,λ′
[
(2π)4
2Iρ(λ, λ′)δ4
(
kA + kB − pt −n−1∑
i
pi
)
d3pt
2Et(2π)3
n−1∏
i
d3pi
2Ei(2π)3
]
×[
1
Γt
(2π)4
2mt
Γ(λ, λ′)δ4(pt − pb − pν − pℓ)d3pb
2Eb(2π)3d3pν
2Eν(2π)3d3pℓ
2Eℓ(2π)3
]
.
Production part (φt = 0)
∫
d3pt
2Et(2π)3
n−1∏
i
d3pi
2Ei(2π)3(2π)4
2Iρ(λ, λ′)δ4
(
kA + kB − pt −n−1∑
i
pi
)
= dσ2→n(λ, λ′)dEtd cos θt
Decay part (in rest frame of top quark)
1
Γt
(2π)4
2mt
∫
d3pb
2Eb(2π)3d3pν
2Eν(2π)3d3pℓ
2Eℓ(2π)3Γ(λ, λ′)δ4(pt − pb − pν − pℓ)
=1
32Γtmt
Eℓ
(2π)4〈Γ(λ, λ′)〉mtEℓ
dEℓdΩℓdp2W
New Physics inSingle-Top Productionat the Large Hadron
Collider
Pankaj Sharma
Korea Institute for
Advanced Study
Seoul
South Korea
Introduction
The Top Quark
Top couplings
Top Polarization
Single top with W−
Angular distribution
of ℓ+
Energy distribution of
ℓ+
CP violation insingle-top
Single top with H−
Top-polarization
Angular distribution
of ℓ+
Conclusions
Angular distribution (contd.)
Combining production and decay part, we get
dσ =1
32Γtmt(2π)4
∑
λ,λ′
dσ2→n(λ, λ′)× g4Acm(λ, λ′)
× dEtd cos θtd cos θℓdφℓ
× EℓF (Eℓ)|∆(p2W )|2dEℓdp2W
New Physics inSingle-Top Productionat the Large Hadron
Collider
Pankaj Sharma
Korea Institute for
Advanced Study
Seoul
South Korea
Introduction
The Top Quark
Top couplings
Top Polarization
Single top with W−
Angular distribution
of ℓ+
Energy distribution of
ℓ+
CP violation insingle-top
Single top with H−
Top-polarization
Angular distribution
of ℓ+
Conclusions
Angular distribution (contd.)
Combining production and decay part, we get
dσ =1
32Γtmt(2π)4
∑
λ,λ′
dσ2→n(λ, λ′)× g4Acm(λ, λ′)
× dEtd cos θtd cos θℓdφℓ
× EℓF (Eℓ)|∆(p2W )|2dEℓdp2W
and
Γt ∝ EℓF (Eℓ)|∆(p2W )|2dEℓdp2W
New Physics inSingle-Top Productionat the Large Hadron
Collider
Pankaj Sharma
Korea Institute for
Advanced Study
Seoul
South Korea
Introduction
The Top Quark
Top couplings
Top Polarization
Single top with W−
Angular distribution
of ℓ+
Energy distribution of
ℓ+
CP violation insingle-top
Single top with H−
Top-polarization
Angular distribution
of ℓ+
Conclusions
Angular distribution (contd.)
Combining production and decay part, we get
dσ =1
32Γtmt(2π)4
∑
λ,λ′
dσ2→n(λ, λ′)× g4Acm(λ, λ′)
× dEtd cos θtd cos θℓdφℓ
× EℓF (Eℓ)|∆(p2W )|2dEℓdp2W
and
Γt ∝ EℓF (Eℓ)|∆(p2W )|2dEℓdp2W
Contributions of anomalous tbW couplings cancels between numeratorand denominator,
New Physics inSingle-Top Productionat the Large Hadron
Collider
Pankaj Sharma
Korea Institute for
Advanced Study
Seoul
South Korea
Introduction
The Top Quark
Top couplings
Top Polarization
Single top with W−
Angular distribution
of ℓ+
Energy distribution of
ℓ+
CP violation insingle-top
Single top with H−
Top-polarization
Angular distribution
of ℓ+
Conclusions
Angular distribution (contd.)
Combining production and decay part, we get
dσ =1
32Γtmt(2π)4
∑
λ,λ′
dσ2→n(λ, λ′)× g4Acm(λ, λ′)
× dEtd cos θtd cos θℓdφℓ
× EℓF (Eℓ)|∆(p2W )|2dEℓdp2W
and
Γt ∝ EℓF (Eℓ)|∆(p2W )|2dEℓdp2W
Contributions of anomalous tbW couplings cancels between numeratorand denominator, if t → bW is the only decay channel
New Physics inSingle-Top Productionat the Large Hadron
Collider
Pankaj Sharma
Korea Institute for
Advanced Study
Seoul
South Korea
Introduction
The Top Quark
Top couplings
Top Polarization
Single top with W−
Angular distribution
of ℓ+
Energy distribution of
ℓ+
CP violation insingle-top
Single top with H−
Top-polarization
Angular distribution
of ℓ+
Conclusions
Angular distribution (contd.)
Combining production and decay part, we get
dσ =1
32Γtmt(2π)4
∑
λ,λ′
dσ2→n(λ, λ′)× g4Acm(λ, λ′)
× dEtd cos θtd cos θℓdφℓ
× EℓF (Eℓ)|∆(p2W )|2dEℓdp2W
and
Γt ∝ EℓF (Eℓ)|∆(p2W )|2dEℓdp2W
Contributions of anomalous tbW couplings cancels between numeratorand denominator, if t → bW is the only decay channel
Thus, angular distribution of decay charged-lepton is independent ofany new physics in the top decay.
New Physics inSingle-Top Productionat the Large Hadron
Collider
Pankaj Sharma
Korea Institute for
Advanced Study
Seoul
South Korea
Introduction
The Top Quark
Top couplings
Top Polarization
Single top with W−
Angular distribution
of ℓ+
Energy distribution of
ℓ+
CP violation insingle-top
Single top with H−
Top-polarization
Angular distribution
of ℓ+
Conclusions
Lepton Azimuthal distribution as top-spin polarizer
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0 π/2 π 3π/2 2π
1/σ
dσ/
dφl
[ r
ad-1
]
φl [ rad ]
LHC 14 TeVSM
σ(+ +)σ(− −)
φℓ distribution is symmetric around φℓ = π.
We define azimuthal asymmetry of charged lepton as :
Aφ =σ(cosφℓ > 0)− σ(cosφℓ < 0)
σ(cosφℓ > 0) + σ(cosφℓ < 0),
New Physics inSingle-Top Productionat the Large Hadron
Collider
Pankaj Sharma
Korea Institute for
Advanced Study
Seoul
South Korea
Introduction
The Top Quark
Top couplings
Top Polarization
Single top with W−
Angular distribution
of ℓ+
Energy distribution of
ℓ+
CP violation insingle-top
Single top with H−
Top-polarization
Angular distribution
of ℓ+
Conclusions
Lepton Azimuthal distribution as top-spin polarizer
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0 π/2 π 3π/2 2π
1/σ
dσ/
dφl
[ r
ad-1
]
φl [ rad ]
LHC 14 TeVSM
σ(+ +)σ(− −)
φℓ distribution is symmetric around φℓ = π.
We define azimuthal asymmetry of charged lepton as :
Aφ =σ(cosφℓ > 0)− σ(cosφℓ < 0)
σ(cosφℓ > 0) + σ(cosφℓ < 0),
Aφ is also left-right asymmetry
New Physics inSingle-Top Productionat the Large Hadron
Collider
Pankaj Sharma
Korea Institute for
Advanced Study
Seoul
South Korea
Introduction
The Top Quark
Top couplings
Top Polarization
Single top with W−
Angular distribution
of ℓ+
Energy distribution of
ℓ+
CP violation insingle-top
Single top with H−
Top-polarization
Angular distribution
of ℓ+
Conclusions
Single top production at LHC
Single top production occurs with large profusion,
Three modes of single-top production are :
1 t-channel production (b u → t d) : ∼ 150 pb
2 s-channel production (u d → t b) : ∼ 10 pb
3 tW -associated production (g b → t W−) : ∼ 30 pb
All these modes have different kinematics and hence can beseparated from each other,
These channels have at least one chiral vertex and hence gives riseto large top-polarization.
provide an alternative to study tbW vertex other than top decay
New Physics inSingle-Top Productionat the Large Hadron
Collider
Pankaj Sharma
Korea Institute for
Advanced Study
Seoul
South Korea
Introduction
The Top Quark
Top couplings
Top Polarization
Single top with W−
Angular distribution
of ℓ+
Energy distribution of
ℓ+
CP violation insingle-top
Single top with H−
Top-polarization
Angular distribution
of ℓ+
Conclusions
tW -associated production at the LHC
g(pg)
b(pb)
W−
t(pt, λt)
b
g(pg)
b(pb) W−
t(pt, λt)
t
tW channel has large background coming from top-pair production.
Several cuts have been proposed to reduce this background in theliterature
CMS and ATLAS have looked for this channel in dilepton mode atthe LHC with 2.1 fb−1 and 0.7 fb−1 of integrated luminosity3
3ATL-CONF-2011-104, CMS PAS TOP-11-022.
New Physics inSingle-Top Productionat the Large Hadron
Collider
Pankaj Sharma
Korea Institute for
Advanced Study
Seoul
South Korea
Introduction
The Top Quark
Top couplings
Top Polarization
Single top with W−
Angular distribution
of ℓ+
Energy distribution of
ℓ+
CP violation insingle-top
Single top with H−
Top-polarization
Angular distribution
of ℓ+
Conclusions
tW -associated production at the LHC
The tW mode helps to isolates tbW couplings
We study effect of anomalous tbW couplings on top polarizationand various kinematical variables of top-decay products
We first obtain top-production and decay density matrix includingfull contribution of anomalous tbW couplings
We find that only f2R gives significant contribution in limit ofvanishing bottom mass mb
New Physics inSingle-Top Productionat the Large Hadron
Collider
Pankaj Sharma
Korea Institute for
Advanced Study
Seoul
South Korea
Introduction
The Top Quark
Top couplings
Top Polarization
Single top with W−
Angular distribution
of ℓ+
Energy distribution of
ℓ+
CP violation insingle-top
Single top with H−
Top-polarization
Angular distribution
of ℓ+
Conclusions
Top polarization and anomalous tbW couplings
-0.4
-0.35
-0.3
-0.25
-0.2
-0.15
-0.1
-0.05
-0.2 -0.15 -0.1 -0.05 0 0.05 0.1 0.15 0.2
Top
pol
ariz
atio
n P
t
Coupling
Top Polarization at 7 TeV
Linear in Ref2RFull contribution in Ref2RFull contribution in Imf2R
-0.4
-0.35
-0.3
-0.25
-0.2
-0.15
-0.1
-0.05
-0.2 -0.15 -0.1 -0.05 0 0.05 0.1 0.15 0.2
Top
pol
ariz
atio
n P
t
Coupling
Top Polarization at 14 TeV
Linear in Ref2RFull contribution in Ref2RFull contribution in Imf2R
σ(±,±) receives contribution from Ref2R at linear order,
Linear approximation is valid for Ref2R ∼ ±0.05.
Ref2R : [−0.011, 0.014], Imf2R : [−0.072, 0.072] for 7 TeV with 5 fb−1
Ref2R : [−0.004, 0.004], Imf2R : [−0.034, 0.034] for 14 TeV with 10 fb−1
New Physics inSingle-Top Productionat the Large Hadron
Collider
Pankaj Sharma
Korea Institute for
Advanced Study
Seoul
South Korea
Introduction
The Top Quark
Top couplings
Top Polarization
Single top with W−
Angular distribution
of ℓ+
Energy distribution of
ℓ+
CP violation insingle-top
Single top with H−
Top-polarization
Angular distribution
of ℓ+
Conclusions
Azimuthal distribution of charged lepton
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
2π3π/2ππ/20
1/σ
dσ/
dφ l
φl
Azimuthal distribution of Charged lepton at 7 TeV
SMRef2R = 0.2Ref2R = -0.2
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
2π3π/2ππ/20
1/σ
dσ/
dφ l
φl
Azimuthal distribution of Charged lepton at 14 TeV
SMRef2R = 0.2Ref2R = -0.2
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
0.5
2π3π/2ππ/20
1/σ
dσ/
dφ l
φl
Azimuthal distribution of Charged lepton at 7 TeV
SMRef2R = 0.2Ref2R = -0.2Imf2R = 0.2
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
0.5
2π3π/2ππ/20
1/σ
dσ/
dφ l
φl
Azimuthal distribution of Charged lepton at 14 TeV
SMRef2R = 0.2Ref2R = -0.2Imf2R = 0.2
We have used the following rapidity and transverse momentumacceptance cuts on the decay lepton: |η| < 2.5, pℓT > 20 GeV.
New Physics inSingle-Top Productionat the Large Hadron
Collider
Pankaj Sharma
Korea Institute for
Advanced Study
Seoul
South Korea
Introduction
The Top Quark
Top couplings
Top Polarization
Single top with W−
Angular distribution
of ℓ+
Energy distribution of
ℓ+
CP violation insingle-top
Single top with H−
Top-polarization
Angular distribution
of ℓ+
Conclusions
Azimuthal asymmetry of charged lepton
We define azimuthal asymmetry of charged lepton as :
Aφ =σ(cosφℓ > 0) − σ(cosφℓ < 0)
σ(cosφℓ > 0) + σ(cosφℓ < 0),
0.25
0.3
0.35
0.4
0.45
0.5
-0.2 -0.15 -0.1 -0.05 0 0.05 0.1 0.15 0.2
Aφ
Coupling
Azimuthal Asymmetry at 7 TeV
Linear in Ref2RFull contribution in Ref2RFull contribution in Imf2R
0.3
0.35
0.4
0.45
0.5
0.55
-0.2 -0.15 -0.1 -0.05 0 0.05 0.1 0.15 0.2
Aφ
Coupling
Azimuthal Asymmetry at 14 TeV
Linear in Ref2RFull contribution in Ref2RFull contribution in Imf2R
Ref2R : [−0.059, 0.087], Imf2R : [−0.067, 0.067] for 7 TeV with 5 fb−1
Ref2R : [−0.034, 0.086], Imf2R : [−0.050, 0.050] for 14 TeV with 10 fb−1
New Physics inSingle-Top Productionat the Large Hadron
Collider
Pankaj Sharma
Korea Institute for
Advanced Study
Seoul
South Korea
Introduction
The Top Quark
Top couplings
Top Polarization
Single top with W−
Angular distribution
of ℓ+
Energy distribution of
ℓ+
CP violation insingle-top
Single top with H−
Top-polarization
Angular distribution
of ℓ+
Conclusions
Energy distribution of charged lepton
0
0.002
0.004
0.006
0.008
0.01
0.012
0.014
0 50 100 150 200 250 300 350 400
1/σd
σ/dE
l
El
Energy distribution of charged lepton at 7 TeV LHC
SMRef2R = -0.2Ref2R = 0.2Imf2R = 0.2
0
0.002
0.004
0.006
0.008
0.01
0.012
0.014
0 50 100 150 200 250 300 350 400
1/σd
σ/dE
l
El
Energy distribution of charged lepton at 14 TeV LHC
SMRef2R = -0.2Ref2R = 0.2Imf2R = 0.2
We use the following cuts on the decay lepton:
|η| < 2.5, pℓT > 20 GeV.
Energy distribution receives contributions of anomalous tbW bothin production and in decay.
The curves of energy distributions intersect at ECℓ = 62GeV .
New Physics inSingle-Top Productionat the Large Hadron
Collider
Pankaj Sharma
Korea Institute for
Advanced Study
Seoul
South Korea
Introduction
The Top Quark
Top couplings
Top Polarization
Single top with W−
Angular distribution
of ℓ+
Energy distribution of
ℓ+
CP violation insingle-top
Single top with H−
Top-polarization
Angular distribution
of ℓ+
Conclusions
Energy asymmetry of charged lepton
Energy asymmetry of charged lepton is defined as :
AEℓ=
σ(Eℓ > ECℓ )− σ(Eℓ < EC
ℓ )
σ(Eℓ > ECℓ ) + σ(Eℓ < EC
ℓ ),
-0.3
-0.25
-0.2
-0.15
-0.1
-0.05
0
0.05
0.1
-0.2 -0.15 -0.1 -0.05 0 0.05 0.1 0.15 0.2
Ene
rgy
Asy
mm
etry
, AE
l
Coupling
Energy Asymmetry at 7 TeV
Ref2RImf2R
-0.3
-0.25
-0.2
-0.15
-0.1
-0.05
0
0.05
0.1
-0.2 -0.15 -0.1 -0.05 0 0.05 0.1 0.15 0.2
Ene
rgy
Asy
mm
etry
, AE
lCoupling
Energy Asymmetry at 14 TeV
Ref2RImf2R
Ref2R : [−0.020, 0.033], Imf2R : [−0.051, 0.051] for 7 TeV with 5 fb−1
Ref2R : [−0.006, 0.009], Imf2R : [−0.038, 0.038] for 14 TeV with 10 fb−1
New Physics inSingle-Top Productionat the Large Hadron
Collider
Pankaj Sharma
Korea Institute for
Advanced Study
Seoul
South Korea
Introduction
The Top Quark
Top couplings
Top Polarization
Single top with W−
Angular distribution
of ℓ+
Energy distribution of
ℓ+
CP violation insingle-top
Single top with H−
Top-polarization
Angular distribution
of ℓ+
Conclusions
Limits on coupling f2R
[−0.012, 0.024] at 1σ with L = 30 fb−1.Single-top production rates, W-helicity fractions
[Aguilar-Savedra, (2008)]
[−0.056, 0.056] Ref2R and on Imf2R [−0.115,0.115] at 3σ withL = 10 fb−1
Single-top production rates, transverse and normal W-polarizationfractions
[Bernabeau, Aguilar-Savedra (2010)]
[−0.6, 0.2] with early LHC dataTop-decay asymmetries at ATLAS and t-channel single-top rates atCMS
[Aguilar-Savedra, Castro, Onofre (2011)]
[−0.026, 0.017] at 1σ with L = 20 fb−1
Using tW -associated production rates
[Najafabadi (2008)]
New Physics inSingle-Top Productionat the Large Hadron
Collider
Pankaj Sharma
Korea Institute for
Advanced Study
Seoul
South Korea
Introduction
The Top Quark
Top couplings
Top Polarization
Single top with W−
Angular distribution
of ℓ+
Energy distribution of
ℓ+
CP violation insingle-top
Single top with H−
Top-polarization
Angular distribution
of ℓ+
Conclusions
CP Violation in tW channel at the LHC
There are a number of proposals for the study of CPV in top-pairproduction at e+e− and pp colliders.
At e+e− and pp colliders, initial state is self conjugate,
CPV in single-top has received little attention.
Reason can be two fold
1 Unlike self-conjugate tt final state, in single top, process involving thas to be related to another involving t
2 Single-top event rate has been low
However, single-top production at the LHC would be substantial
Thus, can be used to extract information on CP violation
New Physics inSingle-Top Productionat the Large Hadron
Collider
Pankaj Sharma
Korea Institute for
Advanced Study
Seoul
South Korea
Introduction
The Top Quark
Top couplings
Top Polarization
Single top with W−
Angular distribution
of ℓ+
Energy distribution of
ℓ+
CP violation insingle-top
Single top with H−
Top-polarization
Angular distribution
of ℓ+
Conclusions
CP Violation in tW channel at the LHC
CPV in single-top has been studied in tH− production in MSSM
[Jung et al], [Christova et al]
But not so far in tW production
Assuming CP Invariance at parton level
dσbg→tW−(x1p1, x2p2, pt, ht, pW−) = dσbg→tW+ (x1p1, x2p2, pt,−ht, pW−)
New Physics inSingle-Top Productionat the Large Hadron
Collider
Pankaj Sharma
Korea Institute for
Advanced Study
Seoul
South Korea
Introduction
The Top Quark
Top couplings
Top Polarization
Single top with W−
Angular distribution
of ℓ+
Energy distribution of
ℓ+
CP violation insingle-top
Single top with H−
Top-polarization
Angular distribution
of ℓ+
Conclusions
CP Violation in tW channel at the LHC
CPV in single-top has been studied in tH− production in MSSM
[Jung et al], [Christova et al]
But not so far in tW production
Assuming CP Invariance at parton level
dσbg→tW−(x1p1, x2p2, pt, ht, pW−) = dσbg→tW+ (x1p1, x2p2, pt,−ht, pW−)
The parton densities of b and g can be related to pdf of b and g in p
⇒for hadron-level cross sections,
dσ(pp → t(pt, ht)W−(pW−)X) = dσ(pp → t(pt,−ht)W
+(pW+)X).
New Physics inSingle-Top Productionat the Large Hadron
Collider
Pankaj Sharma
Korea Institute for
Advanced Study
Seoul
South Korea
Introduction
The Top Quark
Top couplings
Top Polarization
Single top with W−
Angular distribution
of ℓ+
Energy distribution of
ℓ+
CP violation insingle-top
Single top with H−
Top-polarization
Angular distribution
of ℓ+
Conclusions
CP Violation in tW channel at the LHC
CPV in single-top has been studied in tH− production in MSSM
[Jung et al], [Christova et al]
But not so far in tW production
Assuming CP Invariance at parton level
dσbg→tW−(x1p1, x2p2, pt, ht, pW−) = dσbg→tW+ (x1p1, x2p2, pt,−ht, pW−)
The parton densities of b and g can be related to pdf of b and g in p
⇒for hadron-level cross sections,
dσ(pp → t(pt, ht)W−(pW−)X) = dσ(pp → t(pt,−ht)W
+(pW+)X).
A violation of this relation would signal CP Violation.
New Physics inSingle-Top Productionat the Large Hadron
Collider
Pankaj Sharma
Korea Institute for
Advanced Study
Seoul
South Korea
Introduction
The Top Quark
Top couplings
Top Polarization
Single top with W−
Angular distribution
of ℓ+
Energy distribution of
ℓ+
CP violation insingle-top
Single top with H−
Top-polarization
Angular distribution
of ℓ+
Conclusions
Effective vertices
Absence of absorptive parts in the relevant amplitudes leads tofollowing relations :
f∗1L = f1L; f∗
1R = f1R; f∗2L = f2R; f∗
2R = f2L.
New Physics inSingle-Top Productionat the Large Hadron
Collider
Pankaj Sharma
Korea Institute for
Advanced Study
Seoul
South Korea
Introduction
The Top Quark
Top couplings
Top Polarization
Single top with W−
Angular distribution
of ℓ+
Energy distribution of
ℓ+
CP violation insingle-top
Single top with H−
Top-polarization
Angular distribution
of ℓ+
Conclusions
Effective vertices
Absence of absorptive parts in the relevant amplitudes leads tofollowing relations :
f∗1L = f1L; f∗
1R = f1R; f∗2L = f2R; f∗
2R = f2L.
CP conservation implies relations for the form factors
f1L = f1L; f1R = f1R; f2L = f2R; f2R = f2L.
New Physics inSingle-Top Productionat the Large Hadron
Collider
Pankaj Sharma
Korea Institute for
Advanced Study
Seoul
South Korea
Introduction
The Top Quark
Top couplings
Top Polarization
Single top with W−
Angular distribution
of ℓ+
Energy distribution of
ℓ+
CP violation insingle-top
Single top with H−
Top-polarization
Angular distribution
of ℓ+
Conclusions
Effective vertices
Absence of absorptive parts in the relevant amplitudes leads tofollowing relations :
f∗1L = f1L; f∗
1R = f1R; f∗2L = f2R; f∗
2R = f2L.
CP conservation implies relations for the form factors
f1L = f1L; f1R = f1R; f2L = f2R; f2R = f2L.
Parameterizing form factors in following way :
f2L = |f2L| exp (iα2L + iδ2L); f2R = |f2L| exp (iα2L − iδ2L);
f2R = |f2R| exp (iα2R + iδ2R); f2L = |f2R| exp (iα2R − iδ2R),
New Physics inSingle-Top Productionat the Large Hadron
Collider
Pankaj Sharma
Korea Institute for
Advanced Study
Seoul
South Korea
Introduction
The Top Quark
Top couplings
Top Polarization
Single top with W−
Angular distribution
of ℓ+
Energy distribution of
ℓ+
CP violation insingle-top
Single top with H−
Top-polarization
Angular distribution
of ℓ+
Conclusions
Effective vertices
Absence of absorptive parts in the relevant amplitudes leads tofollowing relations :
f∗1L = f1L; f∗
1R = f1R; f∗2L = f2R; f∗
2R = f2L.
CP conservation implies relations for the form factors
f1L = f1L; f1R = f1R; f2L = f2R; f2R = f2L.
Parameterizing form factors in following way :
f2L = |f2L| exp (iα2L + iδ2L); f2R = |f2L| exp (iα2L − iδ2L);
f2R = |f2R| exp (iα2R + iδ2R); f2L = |f2R| exp (iα2R − iδ2R),
∆2R = Ref2L −Ref2R = −2|f2R| sinα2R sin δ2R
New Physics inSingle-Top Productionat the Large Hadron
Collider
Pankaj Sharma
Korea Institute for
Advanced Study
Seoul
South Korea
Introduction
The Top Quark
Top couplings
Top Polarization
Single top with W−
Angular distribution
of ℓ+
Energy distribution of
ℓ+
CP violation insingle-top
Single top with H−
Top-polarization
Angular distribution
of ℓ+
Conclusions
Effective vertices
Absence of absorptive parts in the relevant amplitudes leads tofollowing relations :
f∗1L = f1L; f∗
1R = f1R; f∗2L = f2R; f∗
2R = f2L.
CP conservation implies relations for the form factors
f1L = f1L; f1R = f1R; f2L = f2R; f2R = f2L.
Parameterizing form factors in following way :
f2L = |f2L| exp (iα2L + iδ2L); f2R = |f2L| exp (iα2L − iδ2L);
f2R = |f2R| exp (iα2R + iδ2R); f2L = |f2R| exp (iα2R − iδ2R),
∆2R = Ref2L −Ref2R = −2|f2R| sinα2R sin δ2R
Thus, both absorptive and CP-violating phase have to be present toprobe CP-violation.
New Physics inSingle-Top Productionat the Large Hadron
Collider
Pankaj Sharma
Korea Institute for
Advanced Study
Seoul
South Korea
Introduction
The Top Quark
Top couplings
Top Polarization
Single top with W−
Angular distribution
of ℓ+
Energy distribution of
ℓ+
CP violation insingle-top
Single top with H−
Top-polarization
Angular distribution
of ℓ+
Conclusions
Observables chosen for the analysis
1 Rate asymmetry in tW− and tW+ production
Aσ = σ(pp → tW−)− σ(pp → tW+)
2 Top-polarization asymmetry,
APt= Pt + Pt
3 Charged-lepton azimuthal asymmetry,
ACPVφ = Aφ
ℓ+− Aφ
ℓ−
4 Charged-lepton energy asymmetry,
ACPVEℓ
= AEℓ+
− AEℓ−
All these observables probe CP-violating combination ∆2R
New Physics inSingle-Top Productionat the Large Hadron
Collider
Pankaj Sharma
Korea Institute for
Advanced Study
Seoul
South Korea
Introduction
The Top Quark
Top couplings
Top Polarization
Single top with W−
Angular distribution
of ℓ+
Energy distribution of
ℓ+
CP violation insingle-top
Single top with H−
Top-polarization
Angular distribution
of ℓ+
Conclusions
Results
-0.03
-0.02
-0.01
0
0.01
0.02
0.03
-0.04 -0.02 0 0.02 0.04
AE
lCP
V
∆2R
√s ACPV
σ ACPVPt
ACPVφℓ
ACPVEℓ
ACPV for ∆2R = 1 0.508 0.526 0.198 0.4647 TeV Limit (L = 5 fb−1) 0.0183 0.0180 0.175 0.075
ACPV for ∆2R = 1 0.502 0.536 0.186 0.43814 TeV Limit (L = 10 fb−1) 0.00542 0.00506 0.0343 0.0228
New Physics inSingle-Top Productionat the Large Hadron
Collider
Pankaj Sharma
Korea Institute for
Advanced Study
Seoul
South Korea
Introduction
The Top Quark
Top couplings
Top Polarization
Single top with W−
Angular distribution
of ℓ+
Energy distribution of
ℓ+
CP violation insingle-top
Single top with H−
Top-polarization
Angular distribution
of ℓ+
Conclusions
Results
-0.03
-0.02
-0.01
0
0.01
0.02
0.03
-0.04 -0.02 0 0.02 0.04
AE
lCP
V
∆2R
√s ACPV
σ ACPVPt
ACPVφℓ
ACPVEℓ
ACPV for ∆2R = 1 0.508 0.526 0.198 0.4647 TeV Limit (L = 5 fb−1) 0.0183 0.0180 0.175 0.075
ACPV for ∆2R = 1 0.502 0.536 0.186 0.43814 TeV Limit (L = 10 fb−1) 0.00542 0.00506 0.0343 0.0228
Thus, Energy asymmetry, ACPVEℓ
, is the most sensitive to probe ∆2R
New Physics inSingle-Top Productionat the Large Hadron
Collider
Pankaj Sharma
Korea Institute for
Advanced Study
Seoul
South Korea
Introduction
The Top Quark
Top couplings
Top Polarization
Single top with W−
Angular distribution
of ℓ+
Energy distribution of
ℓ+
CP violation insingle-top
Single top with H−
Top-polarization
Angular distribution
of ℓ+
Conclusions
Associated charged Higgs production with top at LHC
We study the process pp → tH− at LHC, which proceeds throughgb → tH− with tbH− vertex in 2HDM ,
Figure: Born diagrams: s-channel bottom exchange and u-channel topexchange.
Various studies have shown the discovery potential of chargedHiggs in this channel,
Once the charged Higgs will be discovered, the next important taskwould be to determine model parameters mH and tan β,
New Physics inSingle-Top Productionat the Large Hadron
Collider
Pankaj Sharma
Korea Institute for
Advanced Study
Seoul
South Korea
Introduction
The Top Quark
Top couplings
Top Polarization
Single top with W−
Angular distribution
of ℓ+
Energy distribution of
ℓ+
CP violation insingle-top
Single top with H−
Top-polarization
Angular distribution
of ℓ+
Conclusions
Structure of tbH− vertex in 2HDMII
Structure of tbH− interaction vertex :
Γ =g
2√2MW
[mb tan β(1− γ5) +mt cot β(1 + γ5)]
Pt arises mainly only due to parity violating terms viz. γ5 in thevertex,
We expect high degree of top polarization due to the chiral natureof the interaction Lagrangian,
γ5 term vanishes at tan β =√
mt/mb, at this value of tanβ, weexpect Pt to be zero.
New Physics inSingle-Top Productionat the Large Hadron
Collider
Pankaj Sharma
Korea Institute for
Advanced Study
Seoul
South Korea
Introduction
The Top Quark
Top couplings
Top Polarization
Single top with W−
Angular distribution
of ℓ+
Energy distribution of
ℓ+
CP violation insingle-top
Single top with H−
Top-polarization
Angular distribution
of ℓ+
Conclusions
Spin density matrix in top production
The diagonal elements, ρ(±,±), are given by
ρ(+,+) = F1 m2t cot
2 β + F2 m2b tan
2 β
ρ(−,−) = F2 m2t cot
2 β + F1 m2b tan
2 β,
The off-diagonal elements are
ρ(+,−) = ρ(−,+) = (m2t cot
2 β −m2b tan
2 β)F3
F1, F2 and F3 are some kinematical functions of various massesand momenta invovled in the process
Cross section, σ ∝ (F1 + F2)(m2t cot
2 β +m2b tan
2 β)
Polarization, Pt ∝ (F1 − F2)(m2t cot
2 β −m2b tan
2 β)
New Physics inSingle-Top Productionat the Large Hadron
Collider
Pankaj Sharma
Korea Institute for
Advanced Study
Seoul
South Korea
Introduction
The Top Quark
Top couplings
Top Polarization
Single top with W−
Angular distribution
of ℓ+
Energy distribution of
ℓ+
CP violation insingle-top
Single top with H−
Top-polarization
Angular distribution
of ℓ+
Conclusions
Cross section as a function of tan β and mH
Cross section is proportional to (m2t cot
2 β +m2b tan
2 β),
Cross section is minimized at tan β =√
mt/mb
1e-05
1e-04
0.001
0.01
0.1
1
10
100
1000
0 5 10 15 20 25 30 35 40
σ in
fb
tanβ
Cross Section at 7 TeV
mh = 120 GeVmh = 200 GeVmh = 500 GeVmh = 800 GeVmh =1000 GeVmh =1500 GeV
0.001
0.01
0.1
1
10
100
1000
10000
0 5 10 15 20 25 30 35 40
σ in
fb
tanβ
Cross Section at 14 TeV
mh = 120 GeVmh = 200 GeVmh = 500 GeVmh = 800 GeVmh =1000 GeVmh =1500 GeV
Figure: Cross section at 7 and 14 TeV
New Physics inSingle-Top Productionat the Large Hadron
Collider
Pankaj Sharma
Korea Institute for
Advanced Study
Seoul
South Korea
Introduction
The Top Quark
Top couplings
Top Polarization
Single top with W−
Angular distribution
of ℓ+
Energy distribution of
ℓ+
CP violation insingle-top
Single top with H−
Top-polarization
Angular distribution
of ℓ+
Conclusions
Top polarization as a function of tan β nad mH
Top polarization is proportional to (m2t cot
2 β −m2b tan
2 β),
Pt becomes zero at tan β =√
mt/mb,
Pt also zero at a mH ∼ 6mt independent of tan β.
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0 5 10 15 20 25 30 35 40
Pt
tanβ
Top polarization at 14 TeV
mh = 120 GeVmh = 200 GeVmh = 500 GeVmh = 800 GeVmh =1000 GeVmh =1500 GeV
-0.3
-0.2
-0.1
0
0.1
0.2
0.3
200 400 600 800 1000 1200 1400
Pt
mH
Top polarization at 14 TeV
tanβ = 2tanβ = 5tanβ = 10tanβ = 20tanβ = 30tanβ = 40
Figure: Top polarization at 14 TeV
New Physics inSingle-Top Productionat the Large Hadron
Collider
Pankaj Sharma
Korea Institute for
Advanced Study
Seoul
South Korea
Introduction
The Top Quark
Top couplings
Top Polarization
Single top with W−
Angular distribution
of ℓ+
Energy distribution of
ℓ+
CP violation insingle-top
Single top with H−
Top-polarization
Angular distribution
of ℓ+
Conclusions
Azimuthal asymmetry of charged lepton
Azimuthal distribution of charged lepton :
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
2π3π/2ππ/20
1/σd
σ/dφ
l
φl
tanβ=5 at 14 TeV
mH = 200 GeVmH = 500 GeVmH = 800 GeVmH =1000 GeVmH =1500 GeV
W final state in SM
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
2π3π/2ππ/20
1/σd
σ/dφ
l
φl
tanβ=40 at 14 TeV
mH = 200 GeVmH = 500 GeVmH = 800 GeVmH =1000 GeVmH =1500 GeV
W final state in SM
New Physics inSingle-Top Productionat the Large Hadron
Collider
Pankaj Sharma
Korea Institute for
Advanced Study
Seoul
South Korea
Introduction
The Top Quark
Top couplings
Top Polarization
Single top with W−
Angular distribution
of ℓ+
Energy distribution of
ℓ+
CP violation insingle-top
Single top with H−
Top-polarization
Angular distribution
of ℓ+
Conclusions
Azimuthal asymmetry of charged lepton
Azimuthal distribution of charged lepton :
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
2π3π/2ππ/20
1/σd
σ/dφ
l
φl
tanβ=5 at 14 TeV
mH = 200 GeVmH = 500 GeVmH = 800 GeVmH =1000 GeVmH =1500 GeV
W final state in SM
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
2π3π/2ππ/20
1/σd
σ/dφ
l
φl
tanβ=40 at 14 TeV
mH = 200 GeVmH = 500 GeVmH = 800 GeVmH =1000 GeVmH =1500 GeV
W final state in SM
Azimuthal asymmetry of charged lepton :
0.3 0.35
0.4 0.45
0.5 0.55
0.6 0.65
0.7 0.75
0.8 0.85
0 5 10 15 20 25 30 35 40
Aφ
tanβ
Azimuthal Asymmetry at 14 TeV (without cuts)
mH = 120 GeVmH = 200 GeVmH = 500 GeVmH = 800 GeVmH =1000 GeVmH =1500 GeV
0.45
0.5
0.55
0.6
0.65
0.7
0.75
0.8
0.85
0.9
0 5 10 15 20 25 30 35 40
Aφ
tanβ
Azimuthal Asymmetry at 14 TeV (with lepton-cuts)
mH = 120 GeVmH = 200 GeVmH = 500 GeVmH = 800 GeVmH =1000 GeVmH =1500 GeV
We use the following cuts on the decay lepton: |η| < 2.5, pℓT > 20 GeV.
New Physics inSingle-Top Productionat the Large Hadron
Collider
Pankaj Sharma
Korea Institute for
Advanced Study
Seoul
South Korea
Introduction
The Top Quark
Top couplings
Top Polarization
Single top with W−
Angular distribution
of ℓ+
Energy distribution of
ℓ+
CP violation insingle-top
Single top with H−
Top-polarization
Angular distribution
of ℓ+
Conclusions
Sensitivity of Top polarization on tan β
0
0.2
0.4
0.6
0.8
1
0 5 10 15 20 25 30 35 40
∆tan
β/ta
nβ
tanβ
Sensitivites using Pt at 7 TeV
2-σ Confidence LevelIntegrated Luminosity=1 fb-1
mH=120 GeVmH=200 GeV
0
0.2
0.4
0.6
0.8
1
0 5 10 15 20 25 30 35 40
∆tan
β/ta
nβ
tanβ
Sensitivites using Pt at 14 TeV
2-σ Confidence LevelIntegrated Luminosity=10 fb-1
mH=120 GeVmH=200 GeV
Figure: Sensitivity of Pt on tanβ at 7 TeV and 14 TeV
We show 2-σ CL sensivity curves for measurement of tanβ fromPt,
Pt is the most sensitive for tanβ ∼ 3− 20 and tan β ∼ 3− 25 for7 TeV and 14 TeV LHC respectively.
New Physics inSingle-Top Productionat the Large Hadron
Collider
Pankaj Sharma
Korea Institute for
Advanced Study
Seoul
South Korea
Introduction
The Top Quark
Top couplings
Top Polarization
Single top with W−
Angular distribution
of ℓ+
Energy distribution of
ℓ+
CP violation insingle-top
Single top with H−
Top-polarization
Angular distribution
of ℓ+
Conclusions
Sensitivity of Azimuthal asymmetry on tan β
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0 5 10 15 20 25 30 35 40
∆tan
β/ta
nβ
tanβ
Sensitivites using Aφ at 7 TeV
mH=120 GeV
Integrated Luminosity=1 fb-1
1-σ sensitivity2-σ sensitivity
0
0.2
0.4
0.6
0.8
1
0 5 10 15 20 25 30 35 40
∆tan
β/ta
nβ
tanβ
Sensitivites using Aφ at 14 TeV
mH=120 GeVIntegrated Luminosity=10 fb-1
1-σ sensitivity2-σ sensitivity
Figure: Sensitivity of Pt on tanβ at 7 TeV and 14 TeV
We show 1-σ and 2-σ CL sensivity curves for measurement oftanβ from Aφ,
Aφ is the most sensitive for tan β ∼ 5− 13 and tan β ∼ 3− 25 for7 TeV and 14 TeV LHC respectively.
New Physics inSingle-Top Productionat the Large Hadron
Collider
Pankaj Sharma
Korea Institute for
Advanced Study
Seoul
South Korea
Introduction
The Top Quark
Top couplings
Top Polarization
Single top with W−
Angular distribution
of ℓ+
Energy distribution of
ℓ+
CP violation insingle-top
Single top with H−
Top-polarization
Angular distribution
of ℓ+
Conclusions
Conclusions
Top quark polarization provides an additional handle to probe newphysics scenarios.
Azimuthal asymmetry of charged lepton is a clean and pure probeof top-polarization.
Associated-tW production is a good alternative place to look foranomalous tbW couplings other than top-decay
Stringent bounds on Ref2R can be put utlilizing top-polarizationobservables
CP violation in tW production can be probed through the study oftW+ states
In MSSM/2HDM, top-polarization proves to be sensitive probe ofparameter tan β
New Physics inSingle-Top Productionat the Large Hadron
Collider
Pankaj Sharma
Korea Institute for
Advanced Study
Seoul
South Korea
Introduction
The Top Quark
Top couplings
Top Polarization
Single top with W−
Angular distribution
of ℓ+
Energy distribution of
ℓ+
CP violation insingle-top
Single top with H−
Top-polarization
Angular distribution
of ℓ+
Conclusions
Conclusions
Top quark polarization provides an additional handle to probe newphysics scenarios.
Azimuthal asymmetry of charged lepton is a clean and pure probeof top-polarization.
Associated-tW production is a good alternative place to look foranomalous tbW couplings other than top-decay
Stringent bounds on Ref2R can be put utlilizing top-polarizationobservables
CP violation in tW production can be probed through the study oftW+ states
In MSSM/2HDM, top-polarization proves to be sensitive probe ofparameter tan β
THANKS
New Physics inSingle-Top Productionat the Large Hadron
Collider
Pankaj Sharma
Korea Institute for
Advanced Study
Seoul
South Korea
Introduction
The Top Quark
Top couplings
Top Polarization
Single top with W−
Angular distribution
of ℓ+
Energy distribution of
ℓ+
CP violation insingle-top
Single top with H−
Top-polarization
Angular distribution
of ℓ+
Conclusions
Sensitivity analysis
We investigate the accuracy to which one can determine tan βfrom Pt, and Aφ,
Accuracy of the determination of parameter tanβ at tanβ0
is ∆tan β if |O(tan β)−O(tan β0)| < ∆O(tan β0) for| tan β0 − tanβ| < ∆tan β
∆O(tan β0) is the statistical fluctuation in O at an integratedluminosity L,
For Pt and Aφ, the statistical fluctuations at a CL f are given by∆O = f/
√Lσ ×
√1−O2, where O denotes Pt or Aφ.