Early LHC bound on W’ mass in nonuniversal gauge interaction model Kang Young Lee Konkuk University Seoul, Korea 양재교육문화회관
Based on Y. G. Kim, K. Y. Lee, Phys. Lett. B ? (2011) K. Y. Lee, Phys. Rev. D 82, (2010) K. Y. Lee, Phys. Rev. D 76, (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 compatible to the indirect bounds. Violation of the unitarity of the CKM matrix FCNC at tree level
pp → W’ → eν / μν Selection criteria E T > 30 GeV Isolation radius CMS collab., PLB 698, 20 (2011)
CMS collab., arXiv: [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 CMS-PAS-EXO
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, (2007) Chiang, Deshpande, He, Jiang, PRD 81, (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 experiments 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 term Unitarity violated!
Lepton Flavour Violation Non-universal terms in NC interactions separated: Universal terms where
Non-universal terms where
Diagonalization where FCNC arise!
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) |V 32 |, |V 31 | ∼ 0 One of |V 32 |, |V 31 | ∼ 1, the other ∼ 0 3) Either |V 32 | or |V 31 | ∼ 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 width for 1 st, 2 nd gen. for 3 rd gen.
ATLAS 200 pb -1 CMS 36 pb -1 CMS 1.14 fb -1 ATLAS 1.04 fb -1
Direct bounds are 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 beyond the SM directly. Plenty of new physics results are being published. No evidence 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 many people buy the book :