Color-octet scalar effects on Higgs boson production in gluon fusion

Abstract

We compute the next-to-next-to-leading-order QCD corrections to the gluon-fusion production of a Higgs boson in models with massive color-octet scalars in the (8,1)0 representation using an effectivetheory approach. We derive a compact analytic expression for the relevant Wilson coefficient, and explain an interesting technical aspect of the calculation that requires inclusion of the quartic-scalar interactions at next-to-next-to-leading order. We perform a renormalization-group analysis of the scalar couplings to derive the allowed regions of parameter space, and present phenomenological results for both the Tevatron and the LHC. The modifications of the Higgs production cross section are large at both colliders, and can increase the standard model rate by more than a factor of 2 in allowed regions of parameter space. We estimate that stringent constraints on the color-octet scalar parameters can be obtained using the ANL-HEP-PR-10-6Color-octet scalar effects on Higgs boson production in gluon fusion Radja BoughezalInstitute for Theoretical Physics, University of Zurich, Winterthurerstr. 190, 8057 Zurich, Abstract: We compute the next-to-next-to-leading order QCD corrections to the gluonfusion production of a Higgs boson in models with massive color-octet scalars in the (8, 1) 0 representation using an effective-theory approach. We derive a compact analytic expression for the relevant Wilson coefficient, and explain an interesting technical aspect of the calculation that requires inclusion of the quartic-scalar interactions at next-to-next-to-leading order. We perform a renormalization-group analysis of the scalar couplings to derive the allowed regions of parameter space, and present phenomenological results for both the Tevatron and the LHC. The modifications of the Higgs production cross section are large at both colliders, and can increase the Standard Model rate by more than a factor of two in allowed regions of parameter space. We estimate that stringent constraints on the color-octet scalar parameters can be obtained using the Tevatron exclusion limit on Higgs production.

What’s in the loop? The anatomy of double Higgs production

“…In the SM, gg → 1h production receives significant QCD corrections beyond LO QCD. The NNLO contributions from arbitrary fermions [74] and scalars [75,76] are significant. However, since we are typically concerned with ratios relative to the SM, we work at leading order.…”

Scrutinizing the Higgs signal and background in the 2e2μ golden channel

“…Although not as powerful as using the fully differential cross section, with just these two relatively simple expressions one can perform robust analyses of the newly discovered scalar and its coupling to neutral gauge bosons as suggested in [7]. For the signal we give the ϕ → ZZ + Zγ → 2e2µ differential mass spectrum including interference.…”

“…(A.3) of the appendix. Though it does not use all of the kinematic variables, it should still have strong discriminating power and can be used with the methods proposed in [7] to form a powerful simplified study.…”

“…It has been shown in recent studies [3][4][5][6][7][8] and also emphasized for quite some time [9][10][11][12][13], that the decay to four charged leptons is a powerful channel in accomplishing this goal. Because of the experimental precision with which this channel is measured, it offers one of the few opportunities to use analytic methods to analyze the data.…”

A fast track towards the ‘Higgs’ spin and parity

“…Various strategies have been proposed for determining the spin and parity of a Higgs candidate in hadron-hadron collisions, including angular distributions and kinematic correlations in X → ZZ * , W W * and γγ decays [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]. Historically, the problem of determining the spin and parity of a Higgs candidate was first considered in the context of e + e − collisions, and the point was made that the threshold behaviour of the cross section for the 'Higgs'-strahlung process e + e − → Z + X would depend on the spin and parity of the X particle, offering potential discrimination between different spin-parity assignments [23].…”