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Register a new userProbing the spin-parity of the Higgs boson via jet kinematics in vector boson fusion
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Determining the spin and the parity quantum numbers of the recently discovered Higgs-like boson at the LHC is a matter of great importance. In this paper, we consider the possibility of using the kinematics of the tagging jets in Higgs production via the vector boson fusion (VBF) process to test the tensor structure of the Higgs-vector boson ($HVV$) interaction and to determine the spin and CP properties of the observed resonance. We show that an anomalous $HVV$ vertex, in particular its explicit momentum dependence, drastically affects the rapidity between the two scattered quarks and their transverse momenta and, hence, the acceptance of the kinematical cuts that allow to select the VBF topology. The sensitivity of these observables to different spin-parity assignments, including the dependence on the LHC center of mass energy, are evaluated. In addition, we show that in associated Higgs production with a vector boson some kinematical variables, such as the invariant mass of the system and the transverse momenta of the two bosons and their separation in rapidity, are also sensitive to the spin--parity assignments of the Higgs--like boson.
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The data taken in Run II at the LHC have started to probe Higgs boson production at high transverse momentum. Future data will provide a large sample of events with boosted Higgs boson topologies, allowing for a detailed understanding of electroweak Higgs boson plus two-jet production, and in particular the vector-boson fusion mode (VBF). We perform a detailed comparison of precision calculations for Higgs boson production in this channel, with particular emphasis on large Higgs boson transverse momenta, and on the jet radius dependence of the cross section. We study fixed-order predictions at NLO and NNLO QCD, and compare the results to NLO plus parton shower (NLOPS) matched calculations. The impact of the NNLO corrections on the central predictions is mild, with inclusive scale uncertainties of the order of a few percent, which can increase with the imposition of kinematic cuts. We find good agreement between the fixed-order and matched calculations in non-Sudakov regions, and the various NLOPS predictions also agree well in the Sudakov regime. We analyze backgrounds to VBF Higgs boson production stemming from associated production, and from gluon-gluon fusion. At high Higgs boson transverse momenta, the $Delta y_{jj}$ and/or $m_{jj}$ cuts typically used to enhance the VBF signal over background lead to a reduced efficiency. We examine this effect as a function of the jet radius and using different definitions of the tagging jets. QCD radiative corrections increase for all Higgs production modes with increasing Higgs boson $p_T$, but the proportionately larger increase in the gluon fusion channel results in a decrease of the gluon-gluon fusion background to electroweak Higgs plus two jet production upon requiring exclusive two-jet topologies. We study this effect in detail and contrast in particular a central jet veto with a global jet multiplicity requirement.
The production of pairs of Higgs bosons at hadron colliders provides unique information on the Higgs sector and on the mechanism underlying electroweak symmetry breaking (EWSB). Most studies have concentrated on the gluon fusion production mode which has the largest cross section. However, despite its small production rate, the vector-boson fusion channel can also be relevant since even small modifications of the Higgs couplings to vector bosons induce a striking increase of the cross section as a function of the invariant mass of the Higgs boson pair. In this work, we exploit this unique signature to propose a strategy to extract the $hhVV$ quartic coupling and provide model-independent constraints on theories where EWSB is driven by new strong interactions. We take advantage of the higher signal yield of the $bbar b bbar b$ final state and make extensive use of jet substructure techniques to reconstruct signal events with a boosted topology, characteristic of large partonic energies, where each Higgs boson decays to a single collimated jet . Our results demonstrate that the $hhVV$ coupling can be measured with 45% (20%) precision at the LHC for $mathcal{L}=$ 300 (3000) fb$^{-1}$, while a 1% precision can be achieved at a 100 TeV collider.
Deviations from SM expectations in the Higgs sector can be parameterized by an effective Lagrangian. The corresponding anomalous couplings have been implemented in a Monte Carlo program for Higgs production in vector boson fusion, at NLO QCD accuracy. It allows to study anomalous coupling effects for production and decay of the Higgs boson. We analyze deviations allowed by LEP data and study a new azimuthal angle variable which directly measures the interference between CP-even, CP-odd and SM couplings.
The ATLAS and CMS collaborations of the LHC have observed that the Higgs boson decays into the bottom quark-antiquark pair, and have also established that the Higgs coupling with the top quark-antiquark pair is instrumental in one of the modes for Higgs production. This underlines the discovery of the Yukawa force at the LHC. We demonstrate the impact of this discovery on the Higgs properties that are related to the dynamics of electroweak symmetry breaking. We show that these measurements have considerably squeezed the allowed window for new physics contributing to the Higgs couplings with the weak gauge bosons and the third generation quarks. The expected constraints at the HL-LHC and future Higgs factories are also shown. We project these constraints on the parameter space of a few motivated scenarios beyond the Standard Model. We pick them under two broad categories, namely, the composite Higgs and its RS dual, as well as various types of multi-Higgs models. The latter category includes models with singlet scalars, Type I, II and BGL-type two-Higgs doublet models, and models with scalar triplets a la Georgi and Machacek.
The weak-boson fusion process is expected to provide crucial information on Higgs boson couplings at the Large Hadron Collider at CERN. The achievable statistical accuracy demands comparison with next-to-leading order QCD calculations, which are presented here in the form of a fully flexible parton Monte Carlo program. QCD corrections are determined for jet distributions and are shown to be modest, of order 5 to 10% in most cases, but reaching 30% occasionally. Remaining scale uncertainties range from order 5% or less for distributions to below +-2% for the Higgs boson cross section in typical weak-boson fusion search regions.
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