Early LHC bound on W’ mass in nonuniversal gauge interaction model Kang Young Lee Konkuk University Seoul, Korea 핵입자워크샵 @ 양재교육문화회관 2011. 12. 2.

Early LHC bound on W’ massin nonuniversal gauge interaction

model

Kang Young LeeKonkuk University

Seoul, Korea

핵입자워크샵 @ 양재교육문화회관 2011. 12. 2.

• Based on

Y. G. Kim, K. Y. Lee, Phys. Lett. B ? (2011)K. Y. Lee, Phys. Rev. D 82, 097701 (2010)K. Y. Lee, Phys. Rev. D 76, 117702 (2007)

Contents

• Introduction• The Model• Indirect Constraints

• Early LHC bounds on W’• Summary

LEP electroweak precision test Low-energy neutral currents experiments CKM matrix unitarity Lepton flavour violation

LHC is Working Fine!

1.49fb-1 delivered by LHC and 1.38fb-1 recorded by CMS

Introduction• The LHC is running very successfully, data of ~ 5.6

fb-1. are collected in this year. Direct searches for new physics beyond the SM have started at the LHC.

• Non-universal gauge interaction shows distinctive signals

so very strong indirect bounds are obtained.

• Early LHC data provides the direct bounds on the non-universal gauge model, which is already com-patible to the indirect bounds.

Violation of the unitarity of the CKM matrix FCNC at tree level

pp → W’ → eν / μν

Selection criteria

ET > 30 GeV

Isolation radius

CMS collab., PLB 698, 20 (2011)

CMS collab., arXiv:1103.0030 [hep-ex]

Assuming standard-model-like couplings and decay branching fractions we exclude a SSM W’ with mass <2.27 TeV (CMS), <2.15 TeV (ATLAS) @95%CL.

CMS-PAS-EXO-11-024.

The Model

• G = SU(2)l X SU(2)h X U(1)Y

SU(2)L X U(1)Y

U(1)EM

Malkawi, Tait, Yuan, PLB 385, 304 (1996)Muller, Nandi, PLB 383, 345 (1996)Lee, Lee, Kim, PLB 424, 133 (1998)Batra, Delgado, Kaplan, Tait, JHEP 0402, 043 (2002) (SUSY)Lee, PRD 76, 117702 (2007)Chiang, Deshpande, He, Jiang, PRD 81, 015006 (2010)

The covariant derivative

The gauge couplings are parameterized

with

Heavy gauge boson masses

where

Spontaneous symmetry breaking by

with parameterization

LEP electroweak precision test

Corrections to Z → l-l+, Z → bb decays-

Low-energy neutral current experi-ments

νN → νN scattering

νe → νe scattering

eN → eX scattering

Atomic Parity Violation

Data of low-energy neutral current interactions

PDG 2010

CKM matrix unitarity

CKM matrix

Unitarity relation

: Unitarity holds.

: Beta decay

: K decay

: B decay

Non-universal terms in CC interactions separated:

where

with

‘Observed’ CKM matrix is defined by the effective Hamiltonian

and obtained as (including modified W + W’ effects)

Unitarity violating termUnitarityviolated!

Lepton Flavour Violation

Non-universal terms in NC interactions separated:

Universal terms

where

Non-universal terms

where

Diagonalization

where

FCNCarise!

Lepton flavour violating processes

PDG 2010

Flavour diagonal corrections

LEP EW working group

LFV Z decays

LFV τ decays

LFV μ decay is given in the similar form.

1)

2)

|V32|, |V31| 0∼

One of |V32|, |V31| 1, the other 0∼ ∼

3)

Either |V32| or |V31| for unitarity.∼

Corresponding LFV decay exceeds the experimental bound.

In conclusion, only one and others are very small.

Combine all parameters and indirect bounds.

Search for W’ at the LHC

W’ decay width2

'2

' )(sin2

||24

1)''(

f

Wffc Xg

mVNffW

,tan)(sin fX

2sin

11tan

for 1st, 2nd gen.

for 3rd gen.

ATLAS 200 pb-1

CMS 36 pb-1

CMS 1.14 fb-1

ATLAS 1.04 fb-1

Direct boundsare obtained and become better than indirect bounds.

Bound from ATLAS 1.04 fb-1 data

Bound from CMS 36pb-1 data

• The LHC data begin testing the new physics be-yond the SM directly.

• Plenty of new physics results are being published. No ev-idence for BSM physics so far.

• The non-universal SU(2)l X SU(2)h X U(1)Y model predicts many distinct features and has been constrained by various experiments.

• Early LHC data provides direct bounds on this

model which is already compatible to the indirect bounds.

Summary

We are waiting for More Data,

Better Results,

and hope that

New Discovery

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