Conveners
Young Scientists Forum
- Jiri Kvita (Palacky University (CZ))
- Roman Lysak (Acad. of Sciences of the Czech Rep. (CZ))
Many compelling theories to address the Higgs hierarchy problem predict strong interactions between the top and a sector of New Physics. In minimal composite Higgs models (CHM), the top interactions with a BSM strongly-interacting sector give the main contribution to trigger the EWSB and generate a light mass for the pseudo-NG Higgs. This implies that new composite states (VLQ top-partners,...
Search for singly produced vector-like quarks decaying into Wb with one lepton final states is reported using data collected by ATLAS at 13 TeV. The search employs a high-transverse momentum b-tagged jet opposite to the lepton, forward jet originating from the initial-state quark radiating off a W-boson, and no other jet activity in the central region of the detector.
The associated production of a single top quark and a Z boson (tZq) is a rare process predicted by the standard model (SM). Being sensitive to the top-Z and the trilinear gauge couplings, it constitutes an important probe of the SM. While tZq has a moderate cross section, its yield can be enhanced by flavor changing neutral current (FCNC) interactions. The observation of top-FCNCs, which are...
We discuss the impact of EW corrections on differential distributions in top-quark pair production at the LHC and future hadron colliders, focusing on the effects of initial-state photons. Performing a calculation at Next-to-Leading Order QCD+EW accuracy, we investigate in detail the impact of photon-initiated channels on central values as well as PDF and scale uncertainties, both at order...
A combined search for standard model four-top-quark production in the single lepton plus jets and dilepton channels will be presented. The analysis utilises the 2015 dataset recorded by the CMS experiment at $\sqrt{s}$ = 13 TeV which corresponds to an integrated luminosity of 2.6 fb$^{-1}$. A scheme based on a boosted decision tree algorithm is used to select signal and suppress backgrounds....
We present the most recent results on searches for new massive resonances decaying to a top-antitop quark pair with the CMS detector at the LHC.
Searches are performed by measuring the invariant mass distribution of the ttbar system, both in semileptonic and fully-hadronic final states, using the data collected by the CMS experiment in pp collisions at sqrt(s)=13 TeV in 2015, the first year of...
The inclusive cross section of top quark-antiquark pairs produced in $p\bar{p}$ collisions at $\sqrt{s}=1.96$ TeV is measured in lepton$+$jets and dilepton decay channels. The data sample corresponds to 9.7 fb${}^{-1}$ of integrated luminosity recorded with the D0 detector during Run II of the Fermilab Tevatron Collider. Employing multivariate analysis techniques we measure the cross section...
The most precise top quark mass measurements use direct reconstruction methods, determining the top mass parameter of a Monte Carlo event generator, m_t^MC. Due to hadronization and parton shower dynamics, relating m_t^MC to a field theory mass is difficult. We present a calibration procedure to determine this relation by exploiting hadron level QCD predictions for observables closely related...
Differential crosssection measurements of tchannel single topquark production are presented. They use 20.2 fb−1 of data collected by the ATLAS experiment in proton–proton collisions in the LHC at a centreofmass energy of 8 TeV. Differential crosssections as a function of the transverse momentum and rapidity of both the top quark and the top antiquark have been measured at both parton and...
Measurements of the top–antitop quark pair production charge asymmetry in the dilepton c hannel are presented using data corresponding to an integrated luminosity of 20.3 fb−1 from pp collisions at a centerofmass energy of √s = 8 TeV collected with the ATLAS detector. Inclusive and differential measurements as a function of the invariant mass, transverse momentum, and longitudinal boost of...
Top pair events provide a source of bbbar pairs, which can be used to probe CP violation in heavyflavour mixing and decay. In events where one of the W bosons decays leptonically to an electron or muon, the charge of the W boson can be used to determine unambiguously the flavour charge of the accompanying b quark at the time of its production. In cases where the b also decays...
