Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userProduction of electroweak bosons at hadron colliders: theoretical aspects
58
0
0.0
(
0
)
Authors
Michelangelo L. Mangano
Ask ChatGPT about the research
No Arabic abstract
Since the W and Z discovery, hadron colliders have provided a fertile ground, in which continuously improving measurements and theoretical predictions allow to precisely determine the gauge boson properties, and to probe the dynamics of electroweak and strong interactions. This article will review, from a theoretical perspective, the role played by the study, at hadron colliders, of electroweak boson production properties, from the better understanding of the proton structure, to the discovery and studies of the top quark and of the Higgs, to the searches for new phenomena beyond the Standard Model.
rate research
Read More
We report on our recent work on electroweak corrections to $tbar{t}$ production at hadron colliders. Specifically, we discuss the weak-interaction contributions to the top quark transverse momentum and $t bar{t}$ invariant mass distributions and an induced parity-violating top-spin asymmetry.
Results for the complete NLO electroweak corrections to Standard Model Higgs production via gluon fusion are included in the total cross section for hadronic collisions. Artificially large threshold effects are avoided working in the complex-mass scheme. The numerical impact at LHC (Tevatron) energies is explored for Higgs mass values up to 500 GeV (200 GeV). Assuming a complete factorization of the electroweak corrections, one finds a +5 % shift with respect to the NNLO QCD cross section for a Higgs mass of 120 GeV both at the LHC and the Tevatron. Adopting two different factorization schemes for the electroweak effects, an estimate of the corresponding total theoretical uncertainty is computed.
We examine, as model-independently as possible, the production of bileptons at hadron colliders. When a particular model is necessary or useful, we choose the 3-3-1 model. We consider a variety of processes: q anti-q -> Y^{++} Y^{--}, u anti-d -> Y^{++} Y^{-}, anti-u d -> Y^+ Y^{--}, q anti-q -> Y^{++} e^{-} e^{-}, q anti-q -> phi^{++} phi^{--}, u anti-d -> -> phi^{++} phi^{-}, and anti-u d -> phi^{+} phi^{--}, where Y and phi are vector and scalar bileptons, respectively. Given the present low-energy constraints, we find that at the Tevatron, vector bileptons are unobservable, while light scalar bileptons (M_phi <= 300 GeV) are just barely observable. At the LHC, the reach is extended considerably: vector bileptons of mass M_Y <= 1 TeV are observable, as are scalar bileptons of mass M_phi <= 850 GeV.
We consider QCD tbar{t}gamma and tbar{t}Z production at hadron colliders as a tool to measure the ttgamma and ttZ couplings. At the Tevatron it may be possible to perform a first, albeit not very precise, test of the ttgamma vector and axial vector couplings in tbar{t}gamma production, provided that more than 5 fb^{-1} of integrated luminosity are accumulated. The tbar{t}Z cross section at the Tevatron is too small to be observable. At the CERN Large Hadron Collider (LHC) it will be possible to probe the ttgamma couplings at the few percent level, which approaches the precision which one hopes to achieve with a next-generation e^+e^- linear collider. The LHCs capability of associated QCD tbar{t}V (V=gamma, Z) production has the added advantage that the ttgamma and ttZ couplings are not entangled. For an integrated luminosity of 300 fb^{-1}, the ttZ vector (axial vector) coupling can be determined with an uncertainty of 45-85% (15-20%), whereas the dimension-five dipole form factors can be measured with a precision of 50-55%. The achievable limits improve typically by a factor of 2-3 for the luminosity-upgraded (3 ab^{-1}) LHC.
We present a method to compute off-shell effects for processes involving resonant particles at hadron colliders with the possibility to include realistic cuts on the decay products. The method is based on an effective theory approach to unstable particle production and, as an example, is applied to t-channel single top production at the LHC.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
