NLO EW and QCD corrections to polarized ZZ production in the four-charged-lepton channel at the LHC

Measuring the polarization of electroweak bosons at the LHC allows for important tests of the electroweak-symmetry-breaking mechanism that is realized in nature. Therefore, precise Standard Model predictions are needed for the production of polarized bosons in the presence of realistic kinematic selections. We formulate a method for the calculation of polarized cross-sections at NLO that relies on the pole approximation and the separation of polarized matrix elements at the amplitude level. In this framework, we compute NLO-accurate cross-sections for the production of two polarized Z bosons at the LHC, including for the first time NLO EW corrections and combining them with NLO QCD corrections and contributions from the gluon-induced process.

NNLO QCD study of polarised W+W− production at the LHC

Longitudinal polarisation of the weak bosons is a direct consequence of Electroweak symmetry breaking mechanism providing an insight into its nature, and is instrumental in searches for physics beyond the Standard Model. We perform a polarisation study of the diboson production in the pp →$$ {\mathrm{e}}^{+}{v}_{\mathrm{e}}{\mu}^{-}{\overline{v}}_{\mu } $$ e + v e μ − v ¯ μ process at NNLO QCD in the fiducial setup inspired by experimental measurements at ATLAS. This is the first polarisation study at NNLO. We employ the double-pole approximation framework for the polarised calculation, and investigate NNLO effects arising in differential distributions.

Polarization Observables in WZ Production at the 13 TeV LHC: Inclusive Case

We present a study of the polarization observables of the $W$ and $Z$ bosons in the process \(p p \to W^\pm Z\to e^\pm \nu_e \mu^+\mu^-\) at the 13 TeV Large Hadron Collider. The calculation is performed at next-to-leading order, including the full QCD corrections as well as the electroweak corrections, the latter being calculated in the double-pole approximation. The results are presented in the helicity coordinate system adopted by ATLAS and for different inclusive cuts on the di-muon invariant mass. We define left-right charge asymmetries related to the polarization fractions between the \(W^+ Z\) and \(W^- Z\) channels and we find that these asymmetries are large and sensitive to higher-order effects. Similar findings are also presented for charge asymmetries related to a P-even angular coefficient.

Study of vector charmonium electromagnetic Dalitz decays

Using the largest [Formula: see text] and [Formula: see text] data samples in the world, BESIII has measured some charmonium electromagnetic Dalitz decays. Stimulated by the recent experimental results from BESIII, we study the electromagnetic Dalitz decays of [Formula: see text] and [Formula: see text], based on the pointlike QED theory and the simple pole approximation theory, and we present the numerical values of the branching fractions. With the available large samples of [Formula: see text] and [Formula: see text] events collected with the BESIII detector, the expected events for these electromagnetic Dalitz decays are estimated, which offers a unique opportunity to check the theoretical predictions and to measure the transition form factor (TFF). The TFF could characterize the electromagnetic structure arising at the vertex of the transition, and serve as a sensitive probe to the internal structures. These results could be useful for the data taking plan in the future at BESIII.