Four cases of progressive multifocal leukoencephalopathy in iatrogenic immunocompromised patients

Progressive multifocal leukoencephalopathy (PML) is a demyelinating disease of the central nervous system (CNS) caused by John Cunningham Virus (JCV). We report four PML cases in immunocompromised patients, respectively treated with (1) Natalizumab, (2) Rituximab, (3) autologous stem-cell transplantation, and (4) Tacrolimus. All patients underwent neurological examination, magnetic resonance imaging (MRI), magnetic resonance spectroscopy (MRS), JCV-DNA research on biological samples, and lymphocytes subpopulation study. All cases presented with motor, behavioural, and cognitive disorders. Visual, sensitive, and cerebellar deficits developed in three cases. MRI revealed widespread progressive demyelinating areas with active borders; three patients presented contrast enhancement. One patient developed inflammatory reconstitution syndrome (IRIS). At MRS, all cases presented decreased N-acetyl-aspartate (NAA) and three cases showed increased choline (Cho). In one patient, plasma and urine tested positive for JCV-DNA, while cerebrospinal fluid (CSF) analysis confirmed JCV in two patients. The fourth patient had a low JCV-DNA blood titer and brain biopsy showed subacute necrosis. Two patients had abnormal lymphocyte subpopulations. Three patients underwent therapy with Mirtazapine, one of whom received Mefloquine in add-on. No clinical response was registered. Clinical onset, MRI and MRS were highly suggestive of PML in all patients, despite three cases presented contrast enhancement. In three cases JCV-DNA detection in biological samples confirmed the diagnosis. The fourth patient fulfilled diagnosis of “presumptive PML”. Our data confirm the importance to complete the diagnostic workup despite the presence of findings not completely consistent with classical PML. We hypothesize that atypical characteristics could due to the clinical conditions leading to PML

Identification of hadronic tau lepton decays using a deep neural network

A new algorithm is presented to discriminate reconstructed hadronic decays of tau leptons (τh) that originate from genuine tau leptons in the CMS detector against τh candidates that originate from quark or gluon jets, electrons, or muons. The algorithm inputs information from all reconstructed particles in the vicinity of a τh candidate and employs a deep neural network with convolutional layers to efficiently process the inputs. This algorithm leads to a significantly improved performance compared with the previously used one. For example, the efficiency for a genuine τh to pass the discriminator against jets increases by 10–30% for a given efficiency for quark and gluon jets. Furthermore, a more efficient τh reconstruction is introduced that incorporates additional hadronic decay modes. The superior performance of the new algorithm to discriminate against jets, electrons, and muons and the improved τh reconstruction method are validated with LHC proton-proton collision data at √s = 13 TeV

Search for new physics in the lepton plus missing transverse momentum final state in proton-proton collisions at sqrt(s) = 13 TeV

A search for physics beyond the standard model (SM) in final states with an electron or muon and missing transverse momentum is presented. The analysis uses data from proton-proton collisions at a centre-of-mass energy of 13 TeV, collected with the CMS detector at the LHC in 2016-2018 and corresponding to an integrated luminosity of 138 fb(-1). No significant deviation from the SM prediction is observed. Model-independent limits are set on the production cross section of W' bosons decaying into lepton-plus-neutrino final states. Within the framework of the sequential standard model, with the combined results from the electron and muon decay channels a W' boson with mass less than 5.7 TeV is excluded at 95% confidence level. Results on a SM precision test, the determination of the oblique electroweak W parameter, are presented using LHC data for the first time. These results together with those from the direct W' resonance search are used to extend existing constraints on composite Higgs scenarios. This is the first experimental exclusion on compositeness parameters using results from LHC data other than Higgs boson measurements

Search for flavor-changing neutral current interactions of the top quark and Higgs boson in final states with two photons in proton-proton collisions at sqrt(s) = 13 TeV

Proton-proton interactions resulting in final states with two photons are studied in a search for the signature of flavor-changing neutral current interactions of top quarks (t) and Higgs bosons (H). The analysis is based on data collected at a center-of-mass energy of 13 TeV with the CMS detector at the LHC, corresponding to an integrated luminosity of 137 fb(-1.) No significant excess above the background prediction is observed. Upper limits on the branching fractions (B) of the top quark decaying to a Higgs boson and an up (u) or charm (c) quark are derived through a binned fit to the diphoton invariant mass spectrum. The observed (expected) 95% confidence level upper limits are found to be 0.019% (0.031%) for B(t -> Hu) and 0.073% (0.051%) for B(t -> Hc). These are the strictest upper limits yet determined

Search for a W' boson decaying to a vector-like quark and a top or bottom quark in the all-jets final state at sqrt(s) = 13 TeV

A search is presented for a heavy W′ boson resonance decaying to a B or T vector-like quark and a t or a b quark, respectively. The analysis is performed using proton-proton collisions collected with the CMS detector at the LHC. The data correspond to an integrated luminosity of 138 fb−1 at a center-of-mass energy of 13 TeV. Both decay channels result in a signature with a t quark, a Higgs or Z boson, and a b quark, each produced with a significant Lorentz boost. The all-hadronic decays of the Higgs or Z boson and of the t quark are selected using jet substructure techniques to reduce standard model backgrounds, resulting in a distinct three-jet W′ boson decay signature. No significant deviation in data with respect to the standard model background prediction is observed. Upper limits are set at 95% confidence level on the product of the W′ boson cross section and the final state branching fraction. A W′ boson with a mass below 3.1 TeV is excluded, given the benchmark model assumption of democratic branching fractions. In addition, limits are set based on generalizations of these assumptions. These are the most sensitive limits to date for this final state

Measurement of the inclusive and differential WZ production cross sections, polarization angles, and triple gauge couplings in pp collisions at sqrt(s) = 13 TeV

The associated production of a W and a Z boson is studied in final states with multiple leptons produced in proton-proton (pp) collisions at a centre-of-mass energy of 13 TeV using 137 fb−1 of data collected with the CMS detector at the LHC. A measurement of the total inclusive production cross section yields σtot(pp → WZ) = 50.6 ± 0.8 (stat) ± 1.5 (syst) ± 1.1 (lumi) ± 0.5 (theo) pb. Measurements of the fiducial and differential cross sections for several key observables are also performed in all the final-state lepton flavour and charge compositions with a total of three charged leptons, which can be electrons or muons. All results are compared with theoretical predictions computed up to next-to-next-to-leading order in quantum chromodynamics plus next-to-leading or- der in electroweak theory and for various sets of parton distribution functions. The results include direct measurements of the charge asymmetry and the W and Z vector boson polarization. The first observation of longitudinally polarized W bosons in WZ production is reported. Anomalous gauge couplings are searched for, leading to new constraints on beyond-the-standard-model contributions to the WZ triple gauge coupling

Measurements of jet multiplicity and jet transverse momentum in multijet events in proton-proton collisions at sqrt(s) = 13 TeV

Multijet events at large transverse momentum (pT) are measured at s√=13TeV using data recorded with the CMS detector at the LHC, corresponding to an integrated luminosity of 36.3fb−1. The multiplicity of jets with pT>50GeV that are produced in association with a high-pT dijet system is measured in various ranges of the pT of the jet with the highest transverse momentum and as a function of the azimuthal angle difference Δφ1,2 between the two highest pT jets in the dijet system. The differential production cross sections are measured as a function of the transverse momenta of the four highest pT jets. The measurements are compared with leading and next-to-leading order matrix element calculations supplemented with simulations of parton shower, hadronization, and multiparton interactions. In addition, the measurements are compared with next-to-leading order matrix element calculations combined with transverse-momentum dependent parton densities and transverse-momentum dependent parton shower

Search for long-lived heavy neutral leptons with displaced vertices in proton-proton collisions at sqrt(s) = 13 TeV

A search for heavy neutral leptons (HNLs), the right-handed Dirac or Majorana neutrinos, is performed in final states with three charged leptons (electrons or muons) using proton-proton collision data collected by the CMS experiment at s√ = 13 TeV at the CERN LHC. The data correspond to an integrated luminosity of 138 fb−1. The HNLs could be produced through mixing with standard model neutrinos ν. For small values of the HNL mass (<20 GeV) and the square of the HNL-ν mixing parameter (10−7–10−2), the decay length of these particles can be large enough so that the secondary vertex of the HNL decay can be resolved with the CMS silicon tracker. The selected final state consists of one lepton emerging from the primary proton-proton collision vertex, and two leptons forming a displaced, secondary vertex. No significant deviations from the standard model expectations are observed, and constraints are obtained on the HNL mass and coupling strength parameters, excluding previously unexplored regions of parameter space in the mass range 1–20 GeV and squared mixing parameter values as low as 10−7

Search for narrow resonances in the b-tagged dijet mass spectrum in proton-proton collisions at sqrt(s) = 13 TeV

A search is performed for narrow resonances decaying to final states of two jets, with at least one jet originating from a b quark, in proton-proton collisions at √s=13 TeV. The data set corresponds to an integrated luminosity of 138 fb−1 collected with the CMS detector at the LHC. Jets originating from energetic b hadrons are identified through a b-tagging algorithm that utilizes a deep neural network or the presence of a muon inside a jet. The invariant mass spectrum of jet pairs is well described by a smooth parametrization and no evidence for the production of new particles is observed. Upper limits on the production cross section are set for excited b quarks and other resonances decaying to dijet final states containing b quarks. These limits exclude at 95% confidence level models of Z′ bosons with masses from 1.8 TeV to 2.4 TeV and of excited b quarks with masses from 1.8 TeV to 4.0 TeV. This is the most stringent exclusion of excited b quarks to date

Evidence for WW/WZ vector boson scattering in the decay channel l nu q q produced in association with two jets in proton-proton collisions at sqrt(s) = 13 TeV

Evidence is reported for electroweak (EW) vector boson scattering in the decay channel νqq of two weak vector bosons WV (V = W or Z), produced in association with two parton jets. The search uses a data set of proton-proton collisions at 13 TeV collected with the CMS detector during 2016–2018 with an integrated luminosity of 138 fb−1 . Events are selected requiring one lepton (electron or muon), moderate missing transverse momentum, two jets with a large pseudorapidity separation and a large dijet invariant mass, and a signature consistent with the hadronic decay of a W/Z boson. The cross section is computed in a fiducial phase space defined at parton level requiring all parton transverse momenta pT > 10 GeV and at least one pair of outgoing partons with invariant mass mqq > 100 GeV. The measured and expected EW WV production cross sections are 1.90+0.53 −0.46 pb and 2.23+0.08 −0.11(scale) ± 0.05(PDF) pb, respectively, where PDF is the parton distribution function. The observed EW signal strength is μEW = 0.85 ± 0.12 (stat)+0.19 −0.17 (syst), corresponding to a signal significance of 4.4 standard deviations with 5.1 expected, and it is measured keeping the quantum chromodynamics (QCD) associated diboson production fixed to the standard model prediction. This is the first evidence of vector boson scattering in the νqq decay channel at LHC. The simultaneous measurement of the EW and QCD associated diboson production agrees with the standard model prediction