Higgs precision analysis updates 2014

During the 2014 summer conferences, both the ATLAS and CMS Collaborations of the LHC experiments have demonstrated tremendous efforts in treatment of data and processing more data such that most data on signal strengths have improved, especially the diphoton and fermionic modes of both experiments. Here in this paper we perform an update to our previous model-independent Higgs precision analysis—Higgcision. We found the following: (i) the uncertainties on most couplings shrink about 10%–20%, (ii) the nonstandard (e.g. invisible) decay branching ratio of the Higgs boson is constrained to be less than 19% if only the width is allowed to vary, (iii) the gauge-Higgs coupling $C_v$ is constrained to be ${0.94}_{-0.12}^{+0.11}$, in which the uncertainty is reduced by about 10%, and (iv) the standard model (SM) Higgs boson still provides the best fit to all the Higgs boson data, and compared to the previous results the SM Higgs boson now enjoys a higher $p$ value than the last year.

Figure 1

Variation of $\mathrm{\Delta }{\chi }^2$ versus $\mathrm{\Delta }{\mathrm{\Gamma }}_{\mathrm{tot}}$ in the CPC1 case.

Figure 2

The confidence-level regions in the plane of $(C_u^S,C_v)$ of the CPC4 fit by varying $C_u^S$, $C_d^S$, $C_l^S$, and $C_v$ while keeping $\mathrm{\Delta }{S}^{\gamma }=\mathrm{\Delta }{S}^g=\mathrm{\Delta }{\mathrm{\Gamma }}_{\mathrm{tot}}=0$. The contour regions shown are for $\mathrm{\Delta }{\chi }^2\le 2.3$ (red/gray), 5.99 (green/light gray), and 11.83 (blue/dark gray) above the minimum, which correspond to confidence levels of 68.3%, 95%, and 99.7%, respectively. The best-fit point is denoted by the triangle.

Figure 3

The confidence-level regions in the plane of $(C_u^S,C_v)$, $(C_u^S,\mathrm{\Delta }{S}^{\gamma })$, and $(C_u^S,\mathrm{\Delta }{S}^g)$ of the CPC6 fit by varying $C_u^S$, $C_d^S$, $C_l^S$, $C_v$, $\mathrm{\Delta }{S}^{\gamma }$, and $\mathrm{\Delta }{S}^g$. The contour regions shown are for $\mathrm{\Delta }{\chi }^2\le 2.3$ (red/gray), 5.99 (green/light gray), and 11.83 (blue/dark gray) above the minimum, which correspond to confidence levels of 68.3%, 95%, and 99.7%, respectively. The best-fit points are denoted by the triangles.

Figure 4

The confidence-level regions of the fit by varying the scalar Yukawa couplings $C_u^S$ and $C_v$, and the pseudoscalar Yukawa couplings $C_u^P$, while keeping others at the SM values. The description of contour regions is the same as in Fig. 2.

Figure 5

The $p$ values for various fits considered in this work, including CP-conserving (CPC) and CP-violating (CPV) ones.