Article

# Determining the structure of Higgs couplings at the CERN LargeHadron Collider.

Department of Physics, University of Wisconsin, Madison, Wisconsin, USA.

Physical Review Letters (Impact Factor: 7.73). 03/2002; 88(5):051801. DOI: 10.1103/PhysRevLett.88.051801 Source: PubMed

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**ABSTRACT:**We investigate methods to explore the CP nature of the $ t\bar{t}h $ coupling at the LHC, focusing on associated production of the Higgs with a $t \bar{t}$ pair. We first discuss the constraints implied by low-energy observables and by the Higgs-rate information from available LHC data, emphasizing that they cannot provide conclusive evidence on the nature of this coupling. We then investigate kinematic observables that could probe the $ t\bar{t}h $ coupling directly, in particular quantities that can be constructed out of just lab-frame kinematics. We define one such observable by exploiting the fact that $t \bar{t}$ spin correlations do also carry information about the CP-nature of the $ t\bar{t}h $ coupling. Finally, we introduce a CP-odd quantity and a related asymmetry, able to probe CP violation in the $ t\bar{t}h $ coupling and likewise constructed out of lab-frame momenta only.01/2015; - [Show abstract] [Hide abstract]

**ABSTRACT:**An azimuthal angle correlation between two jets is studied in the top quark pair plus multi-jet process at the 14 TeV LHC. The event samples are generated by merging the ttbar plus up to 3 partons matrix elements with parton showers. The generated event samples exhibit a strong azimuthal angle correlation between the two highest p_T jets with large rapidity separation, when the ttbar plus up to 2 or 3 partons matrix elements are properly merged. The distribution of the azimuthal angle correlation differs non-negligibly from the prediction of the matrix element level, mainly because of the strong Sudakov suppression of events with relatively low p_T jets. The impacts of including the ttbar plus 3 partons matrix elements in the merging are studied in detail, and they are found to improve significantly the prediction of the azimuthal angle correlation.01/2015; - [Show abstract] [Hide abstract]

**ABSTRACT:**We analyse the hVV (V = W, Z) vertex in a model independent way using Vh production. To that end , we consider possible corrections to the Standard Model Higgs Lagrangian, in the form of higher dimensional operators which parametrise the effects of new physics. In our analysis, we pay special attention to linear observables that can be used to probe CP violation in the same. By considering the associated production of a Higgs boson with a vector boson (W or Z), we use jet substructure methods to define angular observables which are sensitive to new physics effects, including an asymmetry which is linearly sensitive to the presence of CP odd effects. We demonstrate how to use these observables to place bounds on the presence of higher dimensional operators, and quantify these statements using a log likelihood analysis. Our approach allows one to probe separately the hZZ and hWW vertices, involving arbitrary combinations of BSM operators, at the Large Hadron Collider.09/2014;

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