Littlest Higgs with T-parity: status and prospects

Abstract

The Littlest Higgs model with T-parity is providing an attractive solution to the fine-tuning problem. This solution is only entirely natural if its intrinsic symmetry breaking scale f is relatively close to the electroweak scale. We examine the constraints using the latest results from the 8 TeV run at the LHC. Both direct searches and Higgs precision physics are taken into account. The constraints from Higgs couplings are by now competing with electroweak precision tests and both combined exclude f up to 694 GeV or 560 GeV depending on the implementation of the down-type Yukawa sector. Direct searches provide robust and complementary limits and constrain f to be larger than 638 GeV. We show that the Littlest Higgs model parameter space is slowly driven into the TeV range. Furthermore, we develop a strategy on how to optimise present supersymmetry searches for the considered model, with the goal to improve the constraints and yield more stringent limits on f .

Probing the littlest Higgs model withTparity using di-Higgs events throughZH-pair production at the LHC in NLO QCD

“…An up-to-date overview of the LHT constraints using the latest results from the 8 TeV run at the LHC has been presented in Ref. [24]. In our following calculations we take the related LHT parameters as κ = 1, x L = 1/2, f = 800 GeV, which are within the surviving LHT parameter space, if there is no other statement.…”

“…By adopting the above input parameters, we get the branch ratio Br(Z H → A H h) = 100% [24], and all the partial decay widths of the T -odd quark are numerically obtained by applying the expressions presented in Ref. [27].…”

“…[23][24][25]. The heavy gauge boson pair productions at the leading order (LO) have been sketched in Ref.…”

Associated production of single top and Higgs at the LHC in the littlest Higgs model with T-parity

“…The LHT parameters related to our calculations are the scale f and the ratio R. Considering the consistent constraints in refs. [46][47][48], we require the scale f and the ratio R to vary in the range 500 GeV≤ f ≤ 2000 GeV and 0.1 ≤ R ≤ 3.3. Combined with the global fit of the current Higgs data and the electroweak precision observables (EWPO) in ref.…”

Constraining the Little Higgs model of Schmaltz, Stolarski, and Thaler with recent results from the LHC

“…In general, Little Higgs models without T -parity are more highly constrained by precision electroweak measurements than by the LHC Higgs results [15,16], while T -parity models are primarily constrained by relic abundance considerations [17] and LHC search results [18]. The recent non-T -parity Little Higgs model of Schmaltz, Stolarski and Thaler, which we will refer to as the BLH model [19], is not as constrained by precision measurements due to the presence of a custodial symmetry and a disassociation of the masses of the top partner and heavy gauge boson states.…”