Determining the Structure of Higgs Couplings at the LHC

Higgs boson production via weak boson fusion at the CERN Large Hadron Collider has the capability to determine the dominant CP nature of a Higgs boson, via the tensor structure of its coupling to weak bosons. This information is contained in the azimuthal angle distribution of the two outgoing forward tagging jets. The technique is independent of both the Higgs boson mass and the observed decay channel.Comment: 5 pages, 4 figures, version accepted for publication in PR

Lowering the energy threshold in COSINE-100 dark matter searches

COSINE-100 is a dark matter detection experiment that uses NaI(Tl) crystal detectors operating at the Yangyang underground laboratory in Korea since September 2016. Its main goal is to test the annual modulation observed by the DAMA/LIBRA experiment with the same target medium. Recently DAMA/LIBRA has released data with an energy threshold lowered to 1 keV, and the persistent annual modulation behavior is still observed at 9.5$\sigma$. By lowering the energy threshold for electron recoils to 1 keV, COSINE-100 annual modulation results can be compared to those of DAMA/LIBRA in a model-independent way. Additionally, the event selection methods provide an access to a few to sub-GeV dark matter particles using constant rate studies. In this article, we discuss the COSINE-100 event selection algorithm, its validation, and efficiencies near the threshold

QCD corrections to electroweak l nu_l jj and l^+ l^- jj production

The production of W or Z bosons in association with two jets is an important background to the Higgs boson search in vector-boson fusion at the LHC. The purely electroweak component of this background is dominated by vector-boson fusion, which exhibits kinematic distributions very similar to the Higgs boson signal. We consider the next-to-leading order QCD corrections to the electroweak production of l nu_l jj and l^+ l^- jj events at the LHC, within typical vector-boson fusion cuts. We show that the QCD corrections are modest, increasing the total cross sections by about 10%. Remaining scale uncertainties are below 2%. A fully-flexible next-to-leading order partonic Monte Carlo program allows to demonstrate these features for cross sections within typical vector-boson-fusion acceptance cuts. Modest corrections are also found for distributions.Comment: 26 pages, 10 figures. PRD final version. One reference corrected, introduction expande

Gluon-induced W-boson pair production at the LHC

Pair production of W bosons constitutes an important background to Higgs boson and new physics searches at the Large Hadron Collider LHC. We have calculated the loop-induced gluon-fusion process gg -> W*W* -> leptons, including intermediate light and heavy quarks and allowing for arbitrary invariant masses of the W bosons. While formally of next-to-next-to-leading order, the gg -> W*W* -> leptons process is enhanced by the large gluon flux at the LHC and by experimental Higgs search cuts, and increases the next-to-leading order WW background estimate for Higgs searches by about 30%. We have extended our previous calculation to include the contribution from the intermediate top-bottom massive quark loop and the Higgs signal process. We provide updated results for cross sections and differential distributions and study the interference between the different gluon scattering contributions. We describe important analytical and numerical aspects of our calculation and present the public GG2WW event generator.Comment: 20 pages, 4 figure

Next-to-leading order jet distributions for Higgs boson production via weak-boson fusion

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.Comment: 19 pages, 8 figure

Finite-Width Effects in Top Quark Production at Hadron Colliders

Production cross sections for t\bar{t} and t\bar{t}j events at hadron colliders are calculated, including finite width effects and off resonance contributions for the entire decay chain, t --> bW --> b\ell\nu, for both top quarks. Resulting background rates to Higgs search at the CERN LHC are updated for inclusive H --> WW studies and for H --> \tau\tau and H --> WW decays in weak boson fusion events. Finite width effects are large, increasing t\bar{t}(j) rates by 20% or more, after typical cuts which are employed for top-background rejection.Comment: 32 pages, 11 figures, 7 tables; minor changes, reference added, to be published in Phys. Rev.

NLO Higgs boson production via vector-boson fusion matched with shower in POWHEG

We present a next-to-leading order calculation of Higgs boson production in vector-boson fusion processes interfaced to shower Monte Carlo programs, implemented according to the POWHEG method.Comment: 16 pages, 9 figures. A few references and a new figure adde

Next-to-leading order QCD corrections to Higgs boson production in association with a photon via weak-boson fusion at the LHC

Higgs boson production in association with a hard central photon and two forward tagging jets is expected to provide valuable information on Higgs boson couplings in a range where it is difficult to disentangle weak-boson fusion processes from large QCD backgrounds. We present next-to-leading order QCD corrections to Higgs production in association with a photon via weak-boson fusion at a hadron collider in the form of a flexible parton-level Monte Carlo program. The QCD corrections to integrated cross sections are found to be small for experimentally relevant selection cuts, while the shape of kinematic distributions can be distorted by up to 20% in some regions of phase space. Residual scale uncertainties at next-to-leading order are at the few-percent level.Comment: 17 pages, 7 figures, 1 tabl