The W mass and width measurement challenge at FCC-ee

The FCC-ee physics program will deliver two complementary top-notch precision determinations of the W boson mass, and width. The first and main measurement relies on the rapid rise of the W-pair production cross section near its kinematic threshold. This method is extremely simple and clean, involving only the selection and counting of events, in all different decay channels. An optimal threshold-scan strategy with a total integrated luminosity of $$12\,\mathrm{ab}^{-1}$$ 12 ab - 1 shared on energy points between 157 and 163 GeV will provide a statistical uncertainty on the W mass of 0.5 MeV and on the W width of 1.2 MeV. For these measurements, the goal of keeping the impact of systematic uncertainties below the statistical precision will be demanding, but feasible. The second method exploits the W-pair final state reconstruction and kinematic fit, making use of events with either four jets or two jets, one lepton and missing energy. The projected statistical precision of the second method is similar to the first method’s, with uncertainties of $$\sim 0.5$$ ∼ 0.5 (1) MeV for the W mass (width), employing W-pair data collected at the production threshold and at 240–365 GeV. For the kinematic reconstruction method, the final impact of systematic uncertainties is currently less clear, in particular uncertainties connected to the modeling of the W hadronic decays. The use and interplay of Z$$\gamma $$ γ and ZZ events, reconstructed and fitted with the same techniques as the WW events, will be important for the extraction of W mass measurements with data at the higher 240 and 365 GeV energies.

Search for a heavy vector resonance decaying to a $${\mathrm{Z}}_{\mathrm{}}^{\mathrm{}}$$ boson and a Higgs boson in proton-proton collisions at $$\sqrt{s} = 13\,\text {Te}\text {V} $$

A search is presented for a heavy vector resonance decaying into a $${\mathrm{Z}}_{\mathrm{}}^{\mathrm{}}$$ Z boson and the standard model Higgs boson, where the $${\mathrm{Z}}_{\mathrm{}}^{\mathrm{}}$$ Z boson is identified through its leptonic decays to electrons, muons, or neutrinos, and the Higgs boson is identified through its hadronic decays. The search is performed in a Lorentz-boosted regime and is based on data collected from 2016 to 2018 at the CERN LHC, corresponding to an integrated luminosity of 137$$\,\text {fb}^{-1}$$ fb - 1 . Upper limits are derived on the production of a narrow heavy resonance $${\mathrm{{{\mathrm{Z}}_{\mathrm{}}^{\mathrm{}}}}}_{\mathrm{}}^{\mathrm{\prime }}$$ Z ′ , and a mass below 3.5 and 3.7$$\,\text {Te}\text {V}$$ Te is excluded at 95% confidence level in models where the heavy vector boson couples predominantly to fermions and to bosons, respectively. These are the most stringent limits placed on the Heavy Vector Triplet $${\mathrm{{{\mathrm{Z}}_{\mathrm{}}^{\mathrm{}}}}}_{\mathrm{}}^{\mathrm{\prime }}$$ Z ′ model to date. If the heavy vector boson couples exclusively to standard model bosons, upper limits on the product of the cross section and branching fraction are set between 23 and 0.3$$\,\text {fb}$$ fb for a $${\mathrm{{{\mathrm{Z}}_{\mathrm{}}^{\mathrm{}}}}}_{\mathrm{}}^{\mathrm{\prime }}$$ Z ′ mass between 0.8 and 4.6$$\,\text {Te}\text {V}$$ Te , respectively. This is the first limit set on a heavy vector boson coupling exclusively to standard model bosons in its production and decay.

Hadronic decays of Higgs boson at NNLO matched with parton shower

We present predictions for hadronic decays of the Higgs boson at next-to-next-to-leading order (NNLO) in QCD matched with parton shower based on the POWHEG framework. Those include decays into bottom quarks with full bottom-quark mass dependence, light quarks, and gluons in the heavy top quark effective theory. Our calculations describe exclusive decays of the Higgs boson with leading logarithmic accuracy in the Sudakov region and next-to-leading order (NLO) accuracy matched with parton shower in the three-jet region, with normalizations fixed to the partial width at NNLO. We estimated remaining perturbative uncertainties taking typical event shape variables as an example and demonstrated the need of future improvements on both parton shower and matrix element calculations. The calculations can be used immediately in evaluations of the physics performances of detector designs for future Higgs factories.

Constraining CP4 3HDM with Top Quark Decays

CP4 3HDM is a unique three-Higgs-doublet model equipped with a higher-order CP-symmetry in the scalar and Yukawa sector. Based on a single assumption (the minimal model with a CP-symmetry of order 4 and no accidental symmetry), it leads to a remarkable correlation between its scalar and Yukawa sectors, which echoes in its phenomenology. A recent scan of the parameter space of CP4 3HDM under the assumption of scalar alignment identified a few dozens of points which passed many flavor constraints. In the present work, however, we show that almost all of these points are now ruled out by the recent LHC searches of t→H+b with subsequent hadronic decays of H+. Apart from a few points with charged Higgses heavier than the top quark, only one point survives all the checks, the model with an exotic, non-2HDM-like generation pattern of H+ couplings with quarks. One can expect many more points with exotic H+ couplings to quarks if the scalar alignment assumption is relaxed.

The ATLAS Tile Calorimeter Tools for Data Quality Assessment

The ATLAS Tile Calorimeter (TileCal) is the central part of the hadronic calorimeter of the ATLAS experiment and provides important information for reconstruction of hadrons, jets, hadronic decays of tau leptons and missing transverse energy. The readout is segmented into nearly 10000 channels that are calibrated by means of Cesium source, laser, charge injection, and integratorbased systems. The data quality (DQ) relies on extensive monitoring of both collision and calibration data. Automated checks are performed on a set of pre-defined histograms and results are summarized in dedicated web pages. A set of tools is then used by the operators for further inspection of the acquired data with the goal of spotting the origins of problems or other irregularities. Consequently, the TileCal conditions data (calibration constants, channel statuses etc) are updated in databases that are used for the data-reprocessing, or serve as an important input for the maintenance works during the shutdown periods. This talk reviews the software tools used for the DQ monitoring with emphasis on recent developments aiming to integrate all tools into a single platform.

A puzzle in $$\varvec{\bar{B}_{(s)}^0 \rightarrow D_{(s)}^{(*)+} \lbrace \pi ^-, K^-\rbrace }$$ decays and extraction of the $$\varvec{f_s/f_d}$$ fragmentation fraction

We provide updated predictions for the hadronic decays $$\bar{B}_s^0\rightarrow D_s^{(*)+} \pi ^-$$ B ¯ s 0 → D s ( ∗ ) + π - and $$\bar{B}^0\rightarrow D^{(*)+} K^-$$ B ¯ 0 → D ( ∗ ) + K - . They are based on $${\mathcal {O}}(\alpha _s^2)$$ O ( α s 2 ) results for the QCD factorization amplitudes at leading power and on recent results for the $$\bar{B}_{(s)} \rightarrow D_{(s)}^{(*)}$$ B ¯ ( s ) → D ( s ) ( ∗ ) form factors up to order $$\mathcal{O}(\Lambda _\mathrm{QCD}^2/m_c^2)$$ O ( Λ QCD 2 / m c 2 ) in the heavy-quark expansion. We give quantitative estimates of the matrix elements entering the hadronic decay amplitudes at order $$\mathcal{O}(\Lambda _\mathrm{QCD}/m_b)$$ O ( Λ QCD / m b ) for the first time. Our results are very precise, and uncover a substantial discrepancy between the theory predictions and the experimental measurements. We explore two possibilities for this discrepancy: non-factorizable contributions larger than predicted by the QCD factorization power counting, and contributions beyond the Standard Model. We determine the $$f_s/f_d$$ f s / f d fragmentation fraction for the CDF, D0 and LHCb experiments for both scenarios.