Precise calculation for heavy gauge boson production in the LHT model

Guo Lei,Ma Wen-Gan,Zhang Ren-You

doi:10.1088/1742-6596/523/1/012054

Abstract

In the framework of the littlest Higgs model with T parity, we study the WH/Zh+q_ and WH-pair productions at the CERN Large Hadron Collider up to the QCD next-to-leading order (NLO). The kinematic distributions of final decay products and the theoretical dependence of the cross section on the factorization/renormalization scale are analyzed. We adopt the PROSPINO scheme in the QCD NLO calculations to avoid double counting and keep the convergence of the perturbative QCD description. By using the subtraction scheme, the QCD NLO corrections enhance the leading order cross section with a K-factor in the range of 1.00 ~ 1.43 for WH (ZH)q- production process, and in the range of 1.09 ~ 1.22 for the WH pair production process.

Highlights

Introduction the standard model (SM) [1, 2] provides a remarkably successful description of high energy physics phenomena at the energy scale up to 100 GeV, it leaves a number of theoretical problems unsolved
Among them the little Higgs models deserve attention due to their elegant solution to hierarchy problem and are proposed as one kind of electroweak symmetry breaking (EWSB) models without fine-tuning in which the Higgs boson is naturally light as a result of nonlinearly realized symmetry [9]-[14]
These constraints would enforce the symmetry breaking scale f, which characterizes the mass of new particles, to be larger than 2.5 T eV and 3 T eV respectively

Summary

Introduction

The standard model (SM) [1, 2] provides a remarkably successful description of high energy physics phenomena at the energy scale up to 100 GeV , it leaves a number of theoretical problems unsolved. The littlest Higgs (LH) model [15], an SU (5)/SO(5) nonlinear sigma model [11], is the most simplest version of little Higgs models, in which a set of new heavy gauge bosons (AH , WH , ZH ) and a vector-like quark (T ) are introduced to cancel the quadratic divergence contribution to Higgs boson mass from the SM gauge boson loops and the top quark loop respectively This model predicts large corrections to electroweak precision observables and the scale of the global symmetry breaking f , is constrained by experimental data [12], which set severe constraints on the new heavy particle masses and the model parameters. We present the QCD NLO corrections to the processes pp → WH (ZH )q− + X [27] and pp → WH+WH− + X [28]

The related LHT theory

14 T eV and the 8 T eV

Dependence on global symmetry breaking scale f