The light-fermion contribution to the exact Higgs-gluon form factor in QCD

Abstract

An analytical expression for the three-loop form factors for ggH and γγH is derived for the contributions which involve massless quark loops. The result is expressed in terms of harmonic polylogarithms. It fully agrees with previously obtained kinematical expansions, and confirms a recent semi-numerical approximation which extends over the full kinematic range.

Factorization at subleading power and endpoint-divergent convolutions in h → γγ decay

“…The evolution equations satisfied by the renormalized matching coefficients and matrix elements are derived in Section 5. Using these equations, we predict in Section 6 the large logarithms of order α b α 2 s L k with k = 6, 5, 4, 3 in the three-loop decay amplitude, finding complete agreement with existing multi-loop results in the literature [14,15]. However, we do not confirm previous predictions for the series of subleading logarithms of order α b α n s L 2n+1 [11,16], which were based on conventional resummation techniques.…”

Top Quark Mass Effects in Higgs Boson Production at Four-Loop Order: Virtual Corrections

“…Recently, three-loop corrections to the Higgs-gluon vertex with a massive quark loop have been obtained by combining information from the large-m t and threshold expansions with the help of a conformal mapping and a Padé approximation [18]. For the subset of three-loop diagrams which contain a closed light-quark loop, even analytic results are available [19]. The next-to-next-to-next-to-leading order (N 3 LO) corrections to gg → H within the effective-theory approach have been computed in Refs.…”

Padé approach to top-quark mass effects in gluon fusion amplitudes

“…Padé approach to top-quark mass effects Thomas Rauh Re Im LME to z 7 LME to z 6 Figure 3: The left plot shows our reconstructed results for the three-loop form factor F (2),fin ∆ and the right plot compares our approximation of the fermionic contribution F (2,1),fin ∆ to the analytic calculation (black) from [24]. The blue and yellow regions correspond to our uncertainty estimate for the real and imaginary part of the form factor.…”

“…After the appearance of our work the z 7 coefficient in the LME has been computed in [23] and the light-fermion contributions have been calculated analytically in [24]. In Figure 3 we update our results from [15] with Padé approximants constructed using the additional LME coefficient and compare the fermionic contribution to the exact calculation.…”

“…TTP19-044 P3H-19-049 DESY 19-223 SAGEX- [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] 14th International Symposium on Radiative Corrections (RADCOR2019) 9-13 September 2019 Palais des Papes, Avignon, France…”