Charged-Higgs-boson production at the LHC: Next-to-leading-order supersymmetric QCD corrections

The dominant production process for heavy charged-Higgs bosons at the LHC is the associated production with heavy quarks. We have calculated the next-to-leading-order supersymmetric QCD corrections to charged-Higgs production through the parton processes $q\overline{q},\mathrm{gg}\to \mathrm{tb}{\mathrm{H}}^{\pm }$ and present results for total cross sections and differential distributions. The QCD corrections reduce the renormalization and factorization scale dependence and thus stabilize the theoretical predictions. We present a comparison of the next-to-leading-order results for the inclusive cross section with a calculation based on bottom-gluon fusion $\mathrm{gb}\to \mathrm{t}{\mathrm{H}}^{\pm }$ and discuss the impact of the next-to-leading-order corrections on charged-Higgs searches at the LHC.

Figure 1

A generic set of diagrams (a) for the Born level, (b) for virtual gluon exchange, (c) virtual gluino and squark exchange, (d) gluon radiation, and (e) gluon-(anti)quark scattering in the subprocesses $q\overline{q},\mathrm{gg}\to \mathrm{t}\overline{\mathrm{b}}{\mathrm{H}}^{-}$, etc.

Figure 2

Variation of the LO and NLO cross sections with the renormalization and factorization scales for $\mathrm{pp}\to \mathrm{t}\overline{\mathrm{b}}{\mathrm{H}}^{-}+X$ at the LHC (7 and 14 TeV).

Figure 3

Variation of the LO and NLO cross sections with the renormalization and factorization scales for $\mathrm{pp}\to \mathrm{t}\overline{\mathrm{b}}{\mathrm{H}}^{-}+X$ at the LHC (14 TeV), with a cut of $p_{T,b}>20\mathrm{GeV}$ on the $b$-quark transverse momentum.

Figure 4

Total LO and NLO cross sections for $\mathrm{pp}\to \mathrm{t}\overline{\mathrm{b}}{\mathrm{H}}^{-}+X$ at the LHC (7 and 14 TeV) as a function of the Higgs-boson mass. The lower plots show the $K$ factor, $K={\sigma }_{\mathrm{NLO}}/{\sigma }_{\mathrm{LO}}$, and the scale dependence of the LO and NLO cross-section predictions for ${\mu }_0/3<\mu <3{\mu }_0$.

Figure 5

Total LO and NLO cross sections for $\mathrm{pp}\to \mathrm{t}\overline{\mathrm{b}}{\mathrm{H}}^{-}+X$ at the LHC (14 TeV) as a function of the Higgs-boson mass, with a cut of $p_{T,b}>20\mathrm{GeV}$ on the $b$-quark transverse momentum. The lower plots show the $K$ factor, $K={\sigma }_{\mathrm{NLO}}/{\sigma }_{\mathrm{LO}}$, and the scale dependence of the LO and NLO cross-section predictions for ${\mu }_0/3<\mu <3{\mu }_0$.

Figure 6

NLO transverse-momentum and rapidity distributions of the Higgs boson, the top quark, and the bottom quark for $\mathrm{pp}\to \mathrm{t}\overline{\mathrm{b}}{\mathrm{H}}^{-}+X$ at the LHC (14 TeV).

Figure 7

LO and NLO transverse-momentum and rapidity distributions of the Higgs boson for $\mathrm{pp}\to \mathrm{t}\overline{\mathrm{b}}{\mathrm{H}}^{-}+X$ at the LHC (14 TeV). The lower plot shows the $K$ factor $K={\sigma }_{\mathrm{NLO}}/{\sigma }_{\mathrm{LO}}$.

Figure 8

LO and NLO transverse-momentum and rapidity distributions of the top quark for $\mathrm{pp}\to \mathrm{t}\overline{\mathrm{b}}{\mathrm{H}}^{-}+X$ at the LHC (14 TeV). The lower plot shows the $K$ factor $K={\sigma }_{\mathrm{NLO}}/{\sigma }_{\mathrm{LO}}$.

Figure 9

LO and NLO transverse-momentum and rapidity distributions of the bottom quark for $\mathrm{pp}\to \mathrm{t}\overline{\mathrm{b}}{\mathrm{H}}^{-}+X$ at the LHC (14 TeV). The lower plot shows the $K$ factor $K={\sigma }_{\mathrm{NLO}}/{\sigma }_{\mathrm{LO}}$.

Figure 10

Total NLO cross section for $\mathrm{pp}\to \mathrm{t}{\mathrm{H}}^{-}+X$ at the LHC as a function of the Higgs-boson mass in the 4FS and the 5FS. Shown are the central prediction and the scale dependence for ${\mu }_0/3<\mu <3{\mu }_0$.

Figure 11

Discovery reach for MSSM charged-Higgs bosons ${\mathrm{H}}^{\pm }$, with ${\mathrm{H}}^{\pm }\to \tau \nu$, at CMS [28] as a function of $\tan \beta$ and $M_{{\mathrm{H}}^{\pm }}$. All other supersymmetric parameters have been fixed to the SPS 1b values. Higgs-boson discovery with $\int \mathcal{L}=30{\mathrm{fb}}^{-1}$ is possible in the areas above the curves. Shown are results based on the LO and NLO cross-section calculations in the 4FS with the central scale ${\mu }_0=(m_t+m_b+M_{{\mathrm{H}}^{-}})/3$ and scales set to $\mu ={\mu }_0/3$ and $3{\mu }_0$, respectively.