Total Higgs Boson Research Articles

Measurement of the total and differential Higgs boson production cross-sections at sqrt{s} = 13 TeV with the ATLAS detector by combining the H → ZZ*→ 4ℓ and H → γγ decay channels

The total and differential Higgs boson production cross-sections are measured through a combined statistical analysis of the H → ZZ* → 4ℓ and H → γγ decay channels. The results are based on a dataset of 139 fb−1 of proton–proton collisions at a centre-of-mass energy of 13 TeV, recorded by the ATLAS detector at the Large Hadron Collider. The measured total Higgs boson production cross-section is {55.5}_{-3.8}^{+4.0} pb, consistent with the Standard Model prediction of 55.6 ± 2.5 pb. All results from the two decay channels are compatible with each other, and their combination agrees with the Standard Model predictions. A combined statistical interpretation of the measured fiducial cross-sections as a function of the Higgs boson transverse momentum is performed in order to probe the Yukawa couplings to the bottom and charm quarks. A similar interpretation is performed by including also the constraints from the measurements of Higgs boson production in association with a W or Z boson in the H → boverline{b} and coverline{c} decay channels.

Measurements of Higgs boson production cross sections and couplings in the diphoton decay channel at sqrt{mathrm{s}} = 13 TeV

Measurements of Higgs boson production cross sections and couplings in events where the Higgs boson decays into a pair of photons are reported. Events are selected from a sample of proton-proton collisions at sqrt{s} = 13 TeV collected by the CMS detector at the LHC from 2016 to 2018, corresponding to an integrated luminosity of 137 fb−1. Analysis categories enriched in Higgs boson events produced via gluon fusion, vector boson fusion, vector boson associated production, and production associated with top quarks are constructed. The total Higgs boson signal strength, relative to the standard model (SM) prediction, is measured to be 1.12±0.09. Other properties of the Higgs boson are measured, including SM signal strength modifiers, production cross sections, and its couplings to other particles. These include the most precise measurements of gluon fusion and vector boson fusion Higgs boson production in several different kinematic regions, the first measurement of Higgs boson production in association with a top quark pair in five regions of the Higgs boson transverse momentum, and an upper limit on the rate of Higgs boson production in association with a single top quark. All results are found to be in agreement with the SM expectations.

Higgs boson production at the LHC using the qT subtraction formalism at N3LO QCD

We consider higher-order QCD corrections to Higgs boson production through gluon-gluon fusion in the large top quark mass limit in hadron collisions. We extend the transverse-momentum (qT ) subtraction method to next-to-next-to-next-to-leading order (N3LO) and combine it with the NNLO Higgs-plus-jet calculation to numerically compute differential infrared-safe observables at N3LO for Higgs boson production in gluon fusion. To cancel the infrared divergences, we exploit the universal behaviour of the associated qT distributions in the small-qT region. We document all the necessary ingredients of the transverse-momentum subtraction method up to N3LO. The missing third-order collinear functions, which contribute only at qT = 0, are approximated using a prescription which uses the known result for the total Higgs boson cross section at this order. As a first application of the third-order qT subtraction method, we present the N3LO rapidity distribution of the Higgs boson at the LHC.

Combined measurement of differential and total cross sections in the H → γγ and the H → ZZ⁎ → 4ℓ decay channels at [formula omitted] TeV with the ATLAS detector

A combined measurement of differential and inclusive total cross sections of Higgs boson production is performed using 36.1 fb−1 of 13 TeV proton–proton collision data produced by the LHC and recorded by the ATLAS detector in 2015 and 2016. Cross sections are obtained from measured H→γγ and H→ZZ⁎→4ℓ event yields, which are combined taking into account detector efficiencies, resolution, acceptances and branching fractions. The total Higgs boson production cross section is measured to be 57.0−5.9+6.0 (stat.) −3.3+4.0 (syst.) pb, in agreement with the Standard Model prediction. Differential cross-section measurements are presented for the Higgs boson transverse momentum distribution, Higgs boson rapidity, number of jets produced together with the Higgs boson, and the transverse momentum of the leading jet. The results from the two decay channels are found to be compatible, and their combination agrees with the Standard Model predictions.

Off-shell Higgs coupling measurements in BSM scenarios

Proposals of measuring the off-shell Higgs contributions and first measurements at the LHC have electrified the Higgs phenomenology community for two reasons: firstly, probing interactions at high invariant masses and momentum transfers is intrinsically sensitive to new physics beyond the Standard Model, irrespective of a resonant or non-resonant character of a particular BSM scenario. Secondly, under specific assumptions a class of models exists for which the off-shell coupling measurement together with a measurement of the on-shell signal strength can be re-interpreted in terms of a bound on the total Higgs boson width. In this paper, we provide a first step towards a classification of the models for which a total width measurement is viable and we discuss examples of BSM models for which the off-shell coupling measurement can be important in either constraining or even discovering new physics in the upcoming LHC runs. Specifically, we discuss the quantitative impact of the presence of dimension six operators on the (de)correlation of Higgs on- and off-shell regions keeping track of all interference effects. We furthermore investigate off-shell measurements in a wider context of new (non-)resonant physics in Higgs portal scenarios and the MSSM.

Light Higgs production at a photon collider

We present a preliminary study of the production of a light Higgs boson with a mass between 120 and 160 GeV in photon–photon collisions at a Compton collider. The event generator for the backgrounds to a Higgs signal due to b ̄ b and c ̄ c heavy quark pair production in polarized γγ collisions is based on a complete next-to-leading order (NLO) perturbative QCD calculation. For J z =0 the large double-logarithmic corrections up to four loops are also included. It is shown that the two-photon width of the Higgs boson can be measured with high statistical accuracy of about 2–10% for integrated γγ luminosity in the hard part of the spectrum of 43 fb −1 . From this result the total Higgs boson width can be derived in a model independent way.

HIGGS PHYSICS AT THE LHC

A SM-like Higgs boson can be produced in a variety of channels at the LHC. By combining information from production via gluon fusion and weak boson fusion, various partial widths and the total Higgs boson width can be extracted. Expected accuracies for 200 fb -1 of data are in the 10% range.

Measuring Higgs boson couplings at the CERN LHC

For an intermediate mass Higgs boson with SM-like couplings the CERN LHC allows observation of a variety of decay channels in production by gluon fusion and weak boson fusion. Cross section ratios provide measurements of various ratios of Higgs couplings, with accuracies of order 15% for 100 ${\mathrm{fb}}^{\ensuremath{-}1}$ of data in each of the two LHC experiments. For Higgs boson masses above 120 GeV, minimal assumptions on the Higgs sector allow for an indirect measurement of the total Higgs boson width with an accuracy of 10 to 20 %, and of the $\stackrel{\ensuremath{\rightarrow}}{H}\mathrm{WW}$ partial width with an accuracy of about 10%.

Light Higgs production at the Compton collider

We have studied the production of a light Higgs boson with a mass of 120 GeV in photon-photon collisions at a Compton collider. The event generator for the backgrounds to a Higgs signal due to bb and cc heavy quark pair production in polarized γγ collisions is based on a complete next-to-leading order (NLO) perturbative QCD calculations. For J z = 0 the large double-logarithmic corrections up to four loops are also included. It is shown that the two-photon width of the Higgs boson can be measured with high statistical accuracy of about 2% for integrated γγ luminosity in the hard part of the spectrum of 40 fb −1. As a result the total Higgs boson width can be calculated in a model independent way to an accuracy of about 14%.

The 4-loop quark mass anomalous dimension and the invariant quark mass

We present the analytical calculation of the four-loop quark mass anomalous dimension in Quantum Chromodynamics within the minimal subtraction scheme. On the basis of this result we find that the so-called invariant quark mass is a very good reference mass for the accurate evolution of the running MS-bar quark mass in phenomenological applications. We also obtain for the first time a complete 4-th order perturbative QCD expression for a physical quantity, the total Higgs boson decay rate into hadrons, and analyze the infrared fixed point for this case.