The Standard Model predicts the existence of a fundamental particle, the Higgs Boson, which is the physical manifestation of spontaneous symmetry breaking. The Higgs breaks electroweak symmetry, and is responsible for the masses of the known gauge bosons. Without the Higgs, the Standard Model (SM) is certainly incorrect or at least incomplete. We are at a precipice in the study of particle physics today because the answer to the question of the existence of the Higgs is about to be revealed. Constraints from precision LEP electroweak data indicate that the Higgs is light, less than ∼200 GeV, making it within reach of observation by the high-energy particle colliders Tevatron and LHC.
A promising mode for discovery of the Higgs Boson at the LHC is expected to be in Vector Boson Fusion (VBF) production. The production of Higgs in this mode is the second most copious in the interesting mass region. Furthermore, the interesting kinematics of the process make it likely to be the most sensitive channel. As seen in the figure, two vector bosons are radiated from the quarks of the incoming protons which collide, providing the hard interaction. A Higgs is produced centrally, while the two quarks from which the vector bosons radiated, shower and manifest themselves as high-pT jets in the forward regions of the detector. W and Z bosons are produced via the same mechanism, and have the same kinematic constraints on the spectator jets. When the boson decays leptonically, the central region of the detector is free of hadronic activity. This unique signature provides kinematic discrimination from the copious backgrounds.
My group has been investigating VBF signals at the Tevatron. The large DØ dataset opens the door to a measurement of W and Z produced by this mechanism.
Here are some NLO cross sections for VBF production (computed with VBFNLO) for a variety of final states, taking into account experimental acceptance cuts that are typical at ATLAS and DØ. All cross sections are quoted in nanobarns.
We are investigating the use of multivariate techniques to achieve optimal signal and background separation. Measurements of the rapidity difference between jets in W+2jet events will be an important ingredient in constraining the W+jets backgrounds. These measurements are part of our W+Jets program at DØ.