A search for the Standard Model Higgs boson in proton–proton collisions with the ATLAS detector at the LHC is presented. The datasets used correspond to integrated luminosities of approximately 4.8 fb−1 collected at √s=7 TeV in 2011 and 5.8 fb−1 at √s=8 TeV in 2012. Individual searches in the channels H→ZZ(⁎)→4ℓ, H→γγ and H→WW(⁎)→eνμν in the 8 TeV data are combined with previously published results of searches for H→ZZ(⁎), WW(⁎), bb and τ+τ− in the 7 TeV data and results from improved analyses of the H→ZZ(⁎)→4ℓ and H→γγ channels in the 7 TeV data. Clear evidence for the production of a neutral boson with a measured mass of 126.0±0.4(stat)±0.4(sys) GeV is presented. This observation, which has a significance of 5.9 standard deviations, corresponding to a background fluctuation probability of 1.7×10−9, is compatible with the production and decay of the Standard Model Higgs boson

This paper reports world averages of measurements of b-hadron, c-hadron, and τ -lepton properties obtained by the Heavy Flavour Averaging Group using results available before April 2021. In rare cases, significant results obtained several months later are also used. For the averaging, common input parameters used in the various analyses are adjusted (rescaled) to common values, and known correlations are taken into account. The averages include branching fractions, lifetimes, neutral meson mixing parameters, CP violation parameters, parameters of semileptonic decays, and Cabibbo-Kobayashi-Maskawa matrix elements. Selected world averages -continued from previous page. ∆Γ d /Γ d 0.001 ± 0.010 |q d /p d | 1.0010 ± 0.0008 ∆m s 17.765 ± 0.006 ps −1 ∆Γ s +0.084 ± 0.005 ps −1 |q s /p s | 1.0003 ± 0.0014 φ ccs s −0.049 ± 0.019 rad Unitarity-Triangle angle parameters sin2β ≡ sin2φ 1 0.699 ± 0.017 β ≡ φ 1 (22.2 ± 0.7) • −ηS φK 0 S 0.74 +0.11 −0.13 −ηS η K 0 0.63 ± 0.06 −ηS K 0 S K 0 S K 0 S 0.83 ± 0.17 φ s (φφ) −0.073 ± 0.115 ± 0.027 rad S B 0 s →K + K − , C B 0 s →K + K − (0.14 ± 0.03, 0.17 ± 0.03) −ηS J/ψ π 0 0.86 ± 0.14 −ηS D + D − 0.84 ± 0.12 −ηS J/ψ ρ 0 0.66 +0.13 −0.12 +0.09 −0.03(0.343 ± 0.002)% τ parameters, lepton universality, and |V us | g τ /g µ 1.0009 ± 0.0014 g τ /g e 1.0027 ± 0.0014 g µ /g e 1.0019 ± 0.0014* )0 s B ( * )0 s ) = (87.0 ± 1.7)% [34] measured as described in Ref. [35]. The proportions of the various production channels for non-strange B mesons have also been measured [22]. 4.3 b-hadron production fractions at high energy At high energy, all species of weakly decaying b hadrons may be produced, either directly or in strong and electromagnetic decays of excited b hadrons. Before 2010, it was assumed that the fractions of different species in unbiased samples of high-p T b-hadron jets where independent of whether they originated from Z decays, pp collisions at the Tevatron, or pp collisions at the LHC. This hypothesis was plausible under the condition Q 2 Λ 2 QCD , namely, that the square of the momentum transfer to the produced b quarks is large compared with the square of the hadronization energy scale. This hypothesis is correct in the limit p T → ∞, in which the production mechanism of a b hadron is completely described by the fragmentation of the b quark. For finite p T , however, there are interference effects of the production mechanism of the b quark and its hadronization. While formally suppressed by inverse powers of p T , these effects may be sizable, especially when the fragmentation probabilities are small as, e.g., in the case of b baryons. In fact, the available data show that the fractions depend on the kinematics of the produced b hadron. Both CDF and LHCb reported a p T dependence of the fractions, with the fraction of Λ 0 b baryons observed at low p T being enhanced with respect to that seen at LEP at higher p T . In our previous publication [1], we presented two sets of averages, one including only measurements performed at LEP, and another including only measurements performed ...

A measurement of the Higgs boson mass is presented based on the combined data samples of the ATLAS and CMS experiments at the CERN LHC in the H → γγ and H → ZZ → 4l decay channels. The results are obtained from a simultaneous fit to the reconstructed invariant mass peaks in the two channels and for the two experiments. The measured masses from the individual channels and the two experiments are found to be consistent among themselves. The combined measured mass of the Higgs boson is m H ¼ 125.09 AE 0.21 ðstatÞ AE 0.11 ðsystÞ GeV. DOI: 10.1103/PhysRevLett.114.191803 PACS numbers: 14.80.Bn, 13.85.Qk The study of the mechanism of electroweak symmetry breaking is one of the principal goals of the CERN LHC program. In the standard model (SM), this symmetry breaking is achieved through the introduction of a complex doublet scalar field, leading to the prediction of the Higgs boson H [1-6], whose mass m H is, however, not predicted by the theory. In 2012, the ATLAS and CMS Collaborations at the LHC announced the discovery of a particle with Higgs-boson-like properties and a mass of about 125 GeV [7][8][9]. The discovery was based primarily on mass peaks observed in the γγ and ZZ → l þ l − l 0þ l 0−(denoted H → ZZ → 4l for simplicity) decay channels, where one or both of the Z bosons can be off shell and where l and l 0 denote an electron or muon. With m H known, all properties of the SM Higgs boson, such as its production cross section and partial decay widths, can be predicted. Increasingly precise measurements [10][11][12][13] have established that all observed properties of the new particle, including its spin, parity, and coupling strengths to SM particles are consistent within the uncertainties with those expected for the SM Higgs boson.The ATLAS and CMS Collaborations have independently measured m H using the samples of proton-proton collision data collected in 2011 and 2012, commonly referred to as LHC Run 1. The analyzed samples correspond to approximately 5 fb −1 of integrated luminosity at ffiffi ffi s p ¼ 7 TeV, and 20 fb −1 at ffiffi ffi s p ¼ 8 TeV, for each experiment. Combined results in the context of the separate experiments, as well as those in the individual channels, are presented in Refs. [12,[14][15][16].This Letter describes a combination of the Run 1 data from the two experiments, leading to improved precision for m H . Besides its intrinsic importance as a fundamental parameter, improved knowledge of m H yields more precise predictions for the other Higgs boson properties. Furthermore, the combined mass measurement provides a first step towards combinations of other quantities, such as the couplings. In the SM, m H is related to the values of the masses of the W boson and top quark through loopinduced effects. Taking into account other measured SM quantities, the comparison of the measurements of the Higgs boson, W boson, and top quark masses can be used to directly test the consistency of the SM [17] and thus to search for evidence of physics beyond the SM.The combination is performed usin...

Based on the full BABAR data sample, we report improved measurements of the ratios RðDÞ ¼ BðB ! D À Þ=BðB ! D' À ' Þ and RðD Ã Þ ¼ BðB ! D Ã À Þ=BðB ! D Ã ' À ' Þ, where ' refers to either an electron or muon. These ratios are sensitive to new physics contributions in the form of a charged Higgs boson. We measure RðDÞ ¼ 0:440 AE 0:058 AE 0:042 and RðD Ã Þ ¼ 0:332 AE 0:024 AE 0:018, which exceed the standard model expectations by 2:0 and 2:7, respectively. Taken together, the results disagree with these expectations at the 3:4 level. This excess cannot be explained by a charged Higgs boson in the type II two-Higgs-doublet model. Kinematic distributions presented here exclude large portions of the more general type III two-Higgs-doublet model, but there are solutions within this model compatible with the results.

Based on the full BABAR data sample, we report improved measurements of the ratios R(D(*))=B(B[over ¯]→D(*)τ(-)ν[over ¯](τ))/B(B[over ¯]→D(*)ℓ(ℓ)(-)ν[over ¯](ℓ)), where ℓ is either e or μ. These ratios are sensitive to new physics contributions in the form of a charged Higgs boson. We measure R(D)=0.440±0.058±0.042 and R(D(*))=0.332±0.024±0.018, which exceed the standard model expectations by 2.0σ and 2.7σ, respectively. Taken together, our results disagree with these expectations at the 3.4σ level. This excess cannot be explained by a charged Higgs boson in the type II two-Higgs-doublet model.