arXiv subjects

Duc Ninh Le

Publications and source records attributed to Duc Ninh Le.

15 recordsLinked to original sources

arXiv2026

Triply polarized $WWW$ at the LHC: first glimpse at LO

We present first results for triply polarized $WWW$ events at the LHC. The calculation is performed at leading order for fully leptonic decays using the Standard Model (SM). Employing an inclusive kinematic cut setup, we found that the triply-transverse polarization fraction is about $51\%$, while the triply-longitudinal (LLL) fraction is smallest with $1.4\%$ for the $W^-W^+W^+$ process. The interference between different polarization amplitudes amounts to $+1.8\%$. Results for the $W^+W^-W^-$ case are similar. On the technical side, a new general on-shell mapping for multi-resonance processes, being a crucial element of polarized cross-section calculation, is also presented. Finally, comparisons with the results of MoCaNLO and Sherpa are provided, showing good agreements.

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arXiv2025

Theory overview on polarization and spin-correlations in multi-boson processes

In this contribution, we summarize and discuss recent theoretical progress on the Standard-Model calculation of joint polarized cross sections of massive multi-boson processes with fully leptonic decays. The topics include fixed-order calculation of higher order QCD and electroweak corrections for both production and decay amplitudes, and parton-shower effects.

hep-ph↗

arXiv2025

Effects of bottom quark induced processes on polarized $W^+W^-$ production at the LHC at NLO

In this report we discuss the definition of the polarized cross sections of the inclusive $W^+W^-$ production at the LHC. Results at the level of next-to-leading order (NLO) QCD+EW accuracy, published in our recent paper, are presented to highlight the effects of bottom-quark induced processes. Compared to the unpolarized case, the bottom-induced effects after the subtraction of the on-shell top-quark contribution are more sizable for the doubly-longitudinal polarization.

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arXiv2025

Polarized $W^+W^-$ pairs at the LHC: Effects from bottom-quark induced processes at NLO QCD+EW

We investigate the effects of the bottom-quark induced processes on the doubly polarized cross sections of $W^+W^-$ pair production at the LHC. The method to extract the on-shell single-top contribution is provided. Results for phenomenological and experimental analyses are given at next-to-leading order (NLO) QCD+EW accuracy, with the leading contribution from the gluon-gluon and photon-photon fusion included. We found that the contribution of the bottom-quark induced processes, after the subtraction of the on-shell $tW$ channel, is largest for the doubly longitudinal polarization. At the integrated cross section level, using a fiducial ATLAS cut with a jet veto, the effect is $9\%$ compared to the NLO value of the light-quark contribution. It increases to $13\%$ after removing the jet veto. A bound of the $tW$ interference is calculated for various kinematic distributions, showing that this interference effect is, in general, smaller for the no jet veto case. Relevant scale uncertainties are calculated to help us decide on the importance of this interference.

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arXiv2025

Joint polarizations of W pair production at the LHC at NLO QCD+EW accuracy

In this contribution, we present new results of next-to-leading order (NLO) electroweak corrections to the doubly polarized $W^+W^-$ production cross sections at the LHC, via the full leptonic final state. This calculation has been recently achieved independently by two groups: one in Germany and our group in Vietnam. A comparison of the two results will be presented. We include also the NLO QCD corrections in the numerical analysis since they are dominant and therefore important for comparison with experimental results. New results of integrated cross section for future proton-proton colliders with $\sqrt{s}=$ $27$ TeV, $50$ TeV, $100$ TeV are provided. Moreover, a detailed explanation of the $σ_\text{TT}>σ_\text{LT}>σ_\text{LL}$ hierarchy based on the Born approximation is given.

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arXiv2025

Precise Standard-Model predictions for polarised Z-boson pair production and decay at the LHC

Providing accurate theoretical predictions in the Standard Model for processes with polarised electroweak bosons is crucial to understand more in-depth the electroweak-symmetry breaking mechanism and to enhance the sensitivity to potential new-physics effects. Motivated by the rapidly increasing number of polarisation analyses of di-boson processes with LHC data, we carry out a comprehensive study of the inclusive production of two polarised Z bosons in the decay channel with four charged leptons. We perform a detailed comparison of fixed-order predictions obtained with various Monte Carlo programs which rely on different signal-definition strategies, assessing non-resonant and interference effects by contrasting polarised results with unpolarised and full off-shell ones. For the first time, we accomplish the combination of NNLO QCD and NLO EW corrections, setting the new state-of-the-art perturbative accuracy for polarised Z-boson pairs at the LHC. The impact of parton-shower matching and multi-jet merging is investigated by scrutinising calculations obtained with event generators that are typically used in experimental analyses. Integrated and differential results are discussed in a realistic fiducial setup and compared to publicly available ATLAS results.

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arXiv2024

NLO electroweak corrections to doubly-polarized $W^+W^-$ production at the LHC

We present new results of next-to-leading order (NLO) electroweak corrections to doubly-polarized cross sections of $W^+W^-$ production at the LHC. The calculation is performed for the leptonic final state of $e^+μ_e μ^- \barν_μ$ using the double-pole approximation in the diboson center-of-mass frame. NLO QCD corrections and subleading contributions from the $gg$, $b\bar{b}$, $γγ$ induced processes are taken into account in the numerical results. We found that NLO EW corrections are small for angular distributions but can reach tens of percent for transverse momentum distributions at high energies, e.g. reaching $-40\%$ at $p_{T,e}\approx 300$ GeV. In these high $p_T$ regions, EW corrections are largest for the doubly-transverse mode.

hep-ph↗

arXiv2024

Release Note -- VBFNLO 3.0

VBFNLO is a flexible parton level Monte Carlo program for the simulation of vector boson fusion (VBF), QCD-induced single and double vector boson production plus two jets, and double and triple vector boson production (plus jet) in hadronic collisions at next-to-leading order (NLO) in the strong coupling constant, as well as Higgs boson plus two and three jet production via gluon fusion at the one-loop level. For the new version -- Version 3.0 -- several major enhancements have been included. An interface according to the Binoth Les Houches Accord (BLHA) has been added for all VBF and di/tri-boson processes including fully leptonic decays. For all dimension-8 operators affecting vector boson scattering (VBS) processes, a modified T-matrix unitarization procedure has been implemented. Several new production processes have been added, namely the VBS $Zγjj$ and $γγjj$ processes at NLO, $γγjj $, $WWj$ and $ZZj$ production at NLO including the loop-induced gluon-fusion contributions and the gluon-fusion one-loop induced $Φjjj$ ($Φ$ is a CP-even or CP-odd scalar boson) process at LO, retaining the full top-mass dependence. Finally, the code has been parallelized using OpenMPI.

hep-ph↗

arXiv2024

Toward global fits using Higgs STXS data with Lilith

In this talk, we present the program Lilith, a python package for constraining new physics from Higgs measurements. We discuss the usage of signal strength results in the latest published version of Lilith, which allows for constraining deviations from SM Higgs couplings through coupling modifiers. Moreover, we discuss the on-going development to include Higgs STXS data and SMEFT parametrizations in Lilith with the aim of performing global fits of the ATLAS and CMS data. As we point out, detailed information on Standard Model uncertainties and their correlations is important to enable the proper reuse of the experimental results.

hep-ph↗

arXiv2023

Unparticle effects at the MUonE experiment

We investigate possible effects of unparticles at the MUonE experiment by considering a general model for unparticle with broken scale invariance, characterized by the scaling dimension $d$ and the energy scale $μ$ at which the scale invariance is broken. Taking into account available relevant constraints on the couplings of the unparticles with the Standard Model (SM) leptons, we found that the MUonE experiment at the level of 10 ppm systematic accuracy is sensitive to such effects if $1<d\lesssim 1.4$ and $1\le μ\lesssim 12$ GeV for vector unparticles. The effects of scalar unparticles are too feeble to be detected. The vector unparticles can induce a significant shift on the best-fit value of $a_μ^\text{had}$ at the MUonE, thereby providing an opportunity to detect unparticles or to obtain a new bound on the unparticle-SM couplings in the case of no anomaly.

hep-ph↗

arXiv2023

Broken scale invariant unparticle physics and its prospective effects on the MuonE experiment

We investigate the effects of broken scale invariant unparticle at the MUonE experiment. The choice of the broken model is because the original scale-invariant model is severely suppressed by constraints from cosmology and low-energy experiments. Broken scale invariant unparticle model is categorized into four types: pseudoscalar, scalar, axial-vector, and vector unparticle. Each uparticle type is characterized by three free parameters: coupling constant $λ$, scaling dimension $d$, and energy scale $μ$ at which the scale-invariance is broken. After considering all of the available constraints on the model, we find that the MUonE experiment is sensitive to (axial-)vector unparticle with $1 < d < 1.4$ and $1\le μ\le 12$ GeV.

hep-ph↗

arXiv2023

Enhancing the doubly-longitudinal polarization in WZ production at the LHC

We present new results for the theoretical prediction of doubly-polarized cross sections of $WZ$ events at the LHC using leptonic decays. Compared to the previous studies, two new kinematic cuts are considered. These cuts are designed to enhance the doubly-longitudinal (LL) polarization and, at the same time, study the Radiation Amplitude Zero effect. We found a new cut on the rapidity separation between the $Z$ boson and the electron from the $W$ decay which makes the LL fraction largest, namely $|Δy_{Z,e}| < 0.5$. This result is obtained at the next-to-leading order in the strong and electroweak couplings.

hep-ph↗

arXiv2022

Doubly-polarized $WZ$ hadronic production at NLO QCD+EW: Calculation method and further results

The doubly-polarized production of $W^\pm Z$ pairs at the Large Hadron Collider (LHC) is presented at next-to-leading order (NLO) accuracy both for the electroweak (EW) and QCD corrections, including a detailed description of the calculational method using the double-pole approximation. Numerical results at the 13 TeV LHC are presented in particular for the $W^- Z$ case in the $e^-\barν_e μ^+μ^-$ channel using ATLAS fiducial cuts and for polarized distributions defined in the $WZ$ center-of-mass system. The NLO EW corrections relative to the NLO QCD predictions are found to be smaller than $5\%$ in most kinematic distributions, but can reach the level of $10\%$ in some distributions such as lepton transverse momentum distributions or rapidity separation between the electron and the $Z$ boson. EW corrections are not uniform for different polarizations. A comparison between the new ATLAS measurement of polarization fractions to our theoretical prediction is presented.

hep-ph↗

arXiv2022

Leptonic Anomalous Magnetic and Electric Dipole Moments in the CP-violating NMSSM with and without Inverse Seesaw Mechanism

The new results on the muon anomalous magnetic moment (AMM) published by Fermilab in 2021, did not lead to a reduction of its long-pending deviation from the Standard Model (SM) value by more than 4$σ$. The explanation of this discrepancy by adding new particles to the theory puts many new physics models under tension when combined with the null results of the LHC direct searches for new particles. In this paper, we investigate the CP-violating Next-to-Minimal Supersymmetric extension of the SM (NMSSM) with and without an inverse seesaw mechanism. We compute the one-loop supersymmetric contributions to the AMM and the two-loop Barr-Zee-type diagrams with effective Higgs couplings to photons for the leptonic electric dipole moments (EDMs). The effects of the extended (s)neutrino sector on the muon AMM and on the mass of the SM-like Higgs boson can be significant. Complex phases can have an important impact on the AMM. On the other hand, the stringent limits from the EDMs on the complex phases have to be taken into account. Our calculations have been implemented in the Fortran codes NMSSMCALC and NMSSMCALC-nuSS which are publicly available. Besides the leptonic AMMs and EDMs, these programs can compute the Higgs boson masses and mixings, together with Higgs boson decay widths and branching ratios taking into account the mostup-to-date higher-order corrections in the NMSSM with and without inverse seesaw mechanism.

hep-ph↗

arXiv2022

Doubly-polarized WZ hadronic cross sections at NLO QCD+EW accuracy

We present new results for next-to-leading order (NLO) electroweak (EW) corrections to double polarization signals in the $WZ$ production channel at the LHC using the $e^+ν_e μ^+ μ^-$ final state. It is found that the EW corrections are most sizable in the transverse momentum distributions of the doubly longitudinal polarization, being around -10% compared to the NLO QCD prediction at $p_{T,e}\approx 200$ GeV, which is in the accessible energy range of the current LHC data.

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