The global electroweak fit at NNLO and prospects for the LHC and ILC

For a long time, global fits of the electroweak sector of the Standard Model (SM) have been used to exploit measurements of electroweak precision observables at lepton colliders (LEP, SLC), together with measurements at hadron colliders (Tevatron, LHC), and accurate theoretical predictions at multi-loop level, to constrain free parameters of the SM, such as the Higgs and top masses. Today, all fundamental SM parameters entering these fits are experimentally determined, including information on the Higgs couplings, and the global fits are used as powerful tools to assess the validity of the theory and to constrain scenarios for new physics. Future measurements at the Large Hadron Collider (LHC) and the International Linear Collider (ILC) promise to improve the experimental precision of key observables used in the fits. This paper presents updated electroweak fit results using newest NNLO theoretical predictions, and prospects for the LHC and ILC. The impact of experimental and theoretical uncertainties is analysed in detail. We compare constraints from the electroweak fit on the Higgs couplings with direct LHC measurements, and examine present and future prospects of these constraints using a model with modified couplings of the Higgs boson to fermions and bosons.Comment: 26 pages, 9 figure

Measurement of the top quark mass using the matrix element technique in dilepton final states

We present a measurement of the top quark mass in pp¯ collisions at a center-of-mass energy of 1.96 TeV at the Fermilab Tevatron collider. The data were collected by the D0 experiment corresponding to an integrated luminosity of 9.7  fb−1. The matrix element technique is applied to tt¯ events in the final state containing leptons (electrons or muons) with high transverse momenta and at least two jets. The calibration of the jet energy scale determined in the lepton+jets final state of tt¯ decays is applied to jet energies. This correction provides a substantial reduction in systematic uncertainties. We obtain a top quark mass of mt=173.93±1.84  GeV

B0 s lifetime measurement in the CP-odd decay channel B0 s → J=ψ f 0 (980)

The lifetime of the B0 s meson is measured in the decay channel B0 s → J=ψπþπ− with 880 ≤ Mπþπ− ≤ 1080 MeV=c2, which is mainly a CP-odd state and dominated by the f0ð980Þ resonance. In 10.4 fb−1 of data collected with the D0 detector in Run II of the Tevatron, the lifetime of the B0 s meson is measured to be τ(B0 s) = 1.70 0.14(stat) 0.05(syst) ps. Neglecting CP violation in B0 s=B¯ 0 s mixing, the measurement can be translated into the width of the heavy mass eigenstate of the B0 s, ΓH = 0.59 +- 0.05(stat) 0.02(syst) ps−1

Inclusive Production of the X(4140) State in pp¯ Collisions at D0

We present a study of the inclusive production of the X(4140) state with the decay to the J/ψφ final state in hadronic collisions. Based on 10.4 fb-1 of pp¯ collision data collected by the D0 experiment at the Fermilab Tevatron collider, we report the first evidence for the prompt production of an X(4140) state and find the fraction of X(4140) events originating from b hadrons to be fb=0.39±0.07(stat)±0.10(syst). The ratio of the nonprompt X(4140) production rate to the Bs0 yield in the same channel is R=0.19±0.05(stat)±0.07(syst). The values of the mass M=4152.5±1.7(stat)-5.4+6.2(syst) MeV and width Γ=16.3±5.6(stat)±11.4(syst) MeV are consistent with previous measurements.LAFEX Centro Brasileiro de Pesquisas FísicasUniversidade Do Estado Do Rio de JaneiroUniversidade Federal Do ABCUniversity of Science and Technology of ChinaUniversidad de Los AndesCenter for Particle Physics Faculty of Mathematics and Physics Charles UniversityCzech Technical University in PragueInstitute of Physics Academy of Sciences of the Czech RepublicUniversidad San Francisco de QuitoLPC Université Blaise Pascal CNRS/IN2P3LPSC Université Joseph Fourier Grenoble 1 CNRS/IN2P3 Institut National Polytechnique de GrenobleCPPM Aix-Marseille Université CNRS/IN2P3LAL Université Paris-Sud CNRS/IN2P3LPNHE Universités Paris VI and VII CNRS/IN2P3CEA Irfu SPPIPHC Université de Strasbourg CNRS/IN2P3IPNL Université Lyon 1 CNRS/IN2P3 Université de LyonIII. Physikalisches Institut A RWTH Aachen UniversityPhysikalisches Institut Universität FreiburgII. Physikalisches Institut Georg-August-Universität GöttingenInstitut für Physik Universität MainzLudwig-Maximilians-Universität MünchenPanjab UniversityDelhi UniversityTata Institute of Fundamental ResearchUniversity College DublinKorea Detector Laboratory Korea UniversityCINVESTAVNikhef Science ParkRadboud University NijmegenJoint Institute for Nuclear ResearchInstitute for Theoretical and Experimental PhysicsMoscow State UniversityInstitute for High Energy PhysicsPetersburg Nuclear Physics InstituteInstitució Catalana de Recerca i Estudis Avançats (ICREA) Institut de Física d'Altes Energies (IFAE)Uppsala UniversityTaras Shevchenko National University of KyivLancaster UniversityImperial College LondonUniversity of ManchesterUniversity of ArizonaUniversity of California RiversideFlorida State UniversityFermi National Accelerator LaboratoryUniversity of Illinois at ChicagoNorthern Illinois UniversityNorthwestern UniversityIndiana UniversityPurdue University CalumetUniversity of Notre DameIowa State UniversityUniversity of KansasLouisiana Tech UniversityNortheastern UniversityUniversity of MichiganMichigan State UniversityUniversity of MississippiUniversity of NebraskaRutgers UniversityPrinceton UniversityState University of New YorkUniversity of RochesterBrookhaven National LaboratoryLangston UniversityUniversity of OklahomaOklahoma State UniversityOregon State UniversityBrown UniversityUniversity of TexasSouthern Methodist UniversityRice UniversityUniversity of VirginiaUniversity of WashingtonAugustana CollegeUniversity of LiverpoolDESYCONACyTSLACUniversity College LondonCentro de Investigacion en Computacion-IPNUniversidade Estadual PaulistaKarlsruher Institut für Technologie (KIT) Steinbuch Centre for Computing (SCC)Office of Science U.S. Department of EnergyAmerican Association for the Advancement of ScienceKiev Institute for Nuclear ResearchUniversity of MarylandEuropean Orgnaization for Nuclear Research (CERN)Universidade Estadual Paulist

Measurement of spin correlation between top and antitop quarks produced in pp- collisions at √s = 1.96 TeV

We present a measurement of the correlation between the spins of t and t- quarks produced in proton-antiproton collisions at the Tevatron Collider at a center-of-mass energy of 1.96 TeV. We apply a matrix element technique to dilepton and single-lepton+jets final states in data accumulated with the D0 detector that correspond to an integrated luminosity of 9.7 fb-1. The measured value of the correlation coefficient in the off-diagonal basis, Ooff=0.89±0.22(stat+syst), is in agreement with the standard model prediction, and represents evidence for a top-antitop quark spin correlation difference from zero at a level of 4.2 standard deviations

Measurement of jet fragmentation in Pb+Pb and pp collisions at √s NN =5.02 TeV with the ATLAS detector

This paper presents a measurement of jet fragmentation functions in 0.49 nb −1 of Pb+Pb collisions and 25 pb −1 of pp collisions at √ sNN =5.02 TeV collected in 2015 with the ATLAS detector at the LHC. These measurements provide insight into the jet quenching process in the quark-gluon plasma created in the aftermath of ultra-relativistic collisions between two nuclei. The modifications to the jet fragmentation functions are quantified by dividing the measurements in Pb+Pb collisions by baseline measurements in pp collisions. This ratio is studied as a function of the transverse momentum of the jet, the jet rapidity, and the centrality of the collision. In both collision systems, the jet fragmentation functions are measured for jets with transverse momentum between 126 GeV and 398 GeV and with an absolute value of jet rapidity less than 2.1. An enhancement of particles carrying a small fraction of the jet momentum is observed, which increases with centrality and with increasing jet transverse momentum. Yields of particles carrying a very large fraction of the jet momentum are also observed to be enhanced. Between these two enhancements of the fragmentation functions a suppression of particles carrying an intermediate fraction of the jet momentum is observed in Pb+Pb collisions. A small dependence of the modifications on jet rapidity is observed

Study of double parton interactions in diphoton+dijet events in pp¯ collisions at s√=1.96 TeV

We use a sample of diphoton+dijet events to measure the effective cross section of double parton interactions, which characterizes the area containing the interacting partons in proton-antiproton collisions, and find it to be σeff=19.3±1.4(stat)±7.8(syst)  mb. The sample was collected by the D0 detector at the Fermilab Tevatron collider in pp¯ collisions at s√=1.96  TeV and corresponds to an integrated luminosity of 8.7  fb−1

Tevatron Run II combination of the effective leptonic electroweak mixing angle

Drell-Yan lepton pairs produced in the process pp[over ¯]→ℓ⁺ℓ⁻+X through an intermediate γ*/Z boson have an asymmetry in their angular distribution related to the spontaneous symmetry breaking of the electroweak force and the associated mixing of its neutral gauge bosons. The CDF and D0 experiments have measured the effective-leptonic electroweak mixing parameter sin²θ[subscript eff][superscript lept] using electron and muon pairs selected from the full Tevatron proton-antiproton data sets collected in 2001-2011, corresponding to 9–10  fb⁻¹ of integrated luminosity. The combination of these measurements yields the most precise result from hadron colliders, sin²θ[subscript eff][superscript lept] = 0.23148±0.00033. This result is consistent with, and approaches in precision, the best measurements from electron-positron colliders. The standard model inference of the on-shell electroweak mixing parameter sin²θ[subscript W], or equivalently the W-boson mass M[subscript W], using the zfitter software package yields sin²θ[subscript W] = 0.22324±0.00033 or equivalently, M[subscript W] = 80.367±0.017  GeV/c²

A measurement of the soft-drop jet mass in pp collisions at √s = 13 TeV with the ATLAS detector

Jet substructure observables have significantly extended the search program for physics beyond the Standard Model at the Large Hadron Collider. The state-of-the-art tools have been motivated by theoretical calculations, but there has never been a direct comparison between data and calculations of jet substructure observables that are accurate beyond leading-logarithm approximation. Such observables are significant not only for probing the collinear regime of QCD that is largely unexplored at a hadron collider, but also for improving the understanding of jet substructure properties that are used in many studies at the Large Hadron Collider. This Letter documents a measurement of the first jet substructure quantity at a hadron collider to be calculated at next-to-next-to-leading-logarithm accuracy. The normalized, differential cross-section is measured as a function of log 10 ρ 2, where ρ is the ratio of the soft-drop mass to the ungroomed jet transverse momentum. This quantity is measured in dijet events from 32.9 fb −1 of √s =13 TeV proton-proton collisions recorded by the ATLAS detector. The data are unfolded to correct for detector effects and compared to precise QCD calculations and leading-logarithm particle-level Monte Carlo simulations

Search for Higgs boson decays into a pair of light bosons in the bbμμ final state in pp collision at √s=13 TeV with the ATLAS detector

A search for decays of the Higgs boson into a pair of new spin-zero particles, H→aa, where the a-bosons decay into a b-quark pair and a muon pair, is presented. The search uses 36.1fb−1of proton–proton collision data at √s=13 TeV recorded by the ATLAS experiment at the LHC in 2015 and 2016. No significant deviation from the Standard Model prediction is observed. Upper limits at 95% confidence level are placed on the branching ratio (σH/σSM) ×B(H→aa →bbμμ), ranging from 1.2 ×10−4to 8.4 ×10−4in the a-boson mass range of 20–60GeV. Model-independent limits are set on the visible production cross-section times the branching ratio to the bbμμ final state for new physics, σvis(X) ×B(X→bbμμ), ranging from 0.1fb to 0.73fb for mμμ between 18 and 62GeV