1,000 research outputs found

    An Alternative Explanation for the Equality of Male and Female Unemployment Rates in the U.S. Labor Market in the Late 1980s

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    Given demographic trends, public policies in the future may be aimed at stimulating the availability of nursing home care in the U.S. This paper estimates how certificate of need laws, Medicaid reimbursement rates, and state corporate income tax rates affect the availability of nursing home care in markets throughout the U.S. The results indicate that the Medicaid reimbursement rate directly affects the availability of nursing home care. The findings also suggest that the state corporate tax rate inversely influences the provision of nursing care. Finally, the availability of nursing care is not affected by the presence of certificate of need laws.Female; Unemployment Rate; Unemployment

    A Voucher Supplement To Existing Anti-Discrimination Programs In The Job Market

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    This paper draws on literatures on vouchers and discrimination, and derives an optimal voucher scheme as a supplement to standard anti-discrimination policies, including affirmative action. Surveying current policy methods, it compares efficiency and distributional effects of vouchers to those of the standard enforcement policies. The motivation for vouchers is based on efficiency, equity, and on observed divergence of racial unemployment rates combined with convergence of wage rates.

    Search for a vector-like quark Tâ€Č → tH via the diphoton decay mode of the Higgs boson in proton-proton collisions at s \sqrt{s} = 13 TeV

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    A search for the electroweak production of a vector-like quark Tâ€Č, decaying to a top quark and a Higgs boson is presented. The search is based on a sample of proton-proton collision events recorded at the LHC at = 13 TeV, corresponding to an integrated luminosity of 138 fb−1. This is the first Tâ€Č search that exploits the Higgs boson decay to a pair of photons. For narrow isospin singlet Tâ€Č states with masses up to 1.1 TeV, the excellent diphoton invariant mass resolution of 1–2% results in an increased sensitivity compared to previous searches based on the same production mechanism. The electroweak production of a Tâ€Č quark with mass up to 960 GeV is excluded at 95% confidence level, assuming a coupling strength ÎșT = 0.25 and a relative decay width Γ/MTâ€Č < 5%

    Measurement of the top quark mass using events with a single reconstructed top quark in pp collisions at s\sqrt{s} = 13 TeV

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    A measurement of the top quark mass is performed using a data sample enriched with single top quark events produced in the t channel. The study is based on proton- proton collision data, corresponding to an integrated luminosity of 35.9 fb−1^{-1}, recorded at s\sqrt{s} = 13 TeV by the CMS experiment at the LHC in 2016. Candidate events are selected by requiring an isolated high-momentum lepton (muon or electron) and exactly two jets, of which one is identified as originating from a bottom quark. Multivariate discriminants are designed to separate the signal from the background. Optimized thresholds are placed on the discriminant outputs to obtain an event sample with high signal purity. The top quark mass is found to be 172.13+0.76^{+0.76}−0.77_{-0.77} GeV, where the uncertainty includes both the statistical and systematic components, reaching sub-GeV precision for the first time in this event topology. The masses of the top quark and antiquark are also determined separately using the lepton charge in the final state, from which the mass ratio and difference are determined to be 0.9952+0.0079^{+0.0079}−0.0104_{-0.0104} and 0.83+1.79^{+1.79}−1.35_{-1.35} GeV, respectively. The results are consistent with CPT invariance

    Measurement of the Higgs boson inclusive and differential fiducial production cross sections in the diphoton decay channel with pp collisions at s \sqrt{s} = 13 TeV

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    The measurements of the inclusive and differential fiducial cross sections of the Higgs boson decaying to a pair of photons are presented. The analysis is performed using proton-proton collisions data recorded with the CMS detector at the LHC at a centre-of-mass energy of 13 TeV and corresponding to an integrated luminosity of 137 fb−1^{−1}. The inclusive fiducial cross section is measured to be σfidσ_{fid}=73.4−5.3+5.4^{+5.4}_{−5.3}(stat)−2.2+2.4^{+2.4}_{−2.2}(syst) fb, in agreement with the standard model expectation of 75.4 ± 4.1 fb. The measurements are also performed in fiducial regions targeting different production modes and as function of several observables describing the diphoton system, the number of additional jets present in the event, and other kinematic observables. Two double differential measurements are performed. No significant deviations from the standard model expectations are observed

    Measurement of the Higgs boson width and evidence of its off-shell contributions to ZZ production

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    Since the discovery of the Higgs boson in 2012, detailed studies of its properties have been ongoing. Besides its mass, its width - related to its lifetime - is an important parameter. One way to determine this quantity is by measuring its off-shell production, where the Higgs boson mass is far away from its nominal value, and relating it to its on-shell production, where the mass is close to the nominal value. Here, we report evidence for such off-shell contributions to the production cross section of two Z bosons with data from the CMS experiment at the CERN Large Hadron Collider. We constrain the total rate of the off-shell Higgs boson contribution beyond the Z boson pair production threshold, relative to its standard model expectation, to the interval [0.0061, 2.0] at 95% confidence level. The scenario with no off-shell contribution is excluded at a p-value of 0.0003 (3.6 standard deviations). We measure the width of the Higgs boson as Γ\GammaH_H=3.2−1.7+2.4^{+2.4}_{−1.7}MeV, in agreement with the standard model expectation of 4.1 MeV. In addition, we set constraints on anomalous Higgs boson couplings to W and Z boson pairs

    Search for new particles in an extended Higgs sector with four b quarks in the final state at √s = 13 TeV

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    Measurement of the Dependence of the Hadron Production Fraction Ratios fs/fuf_s / f_u and fd/fuf_d / f_u on BB Meson Kinematic Variables in Proton-Proton Collisions at s=13TeV\sqrt{s} = 13 TeV

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    The dependence of the ratio between the Bs0B^0_s and B+B^+ hadron production fractions, fs/fuf_s/f_u, on the transverse momentum (pT)(p_T) and rapidity of the BB mesons is studied using the decay channels Bs0→J/ψϕB^0_s→J/ψϕ and B+→J/ψK+B^+→J/ψK^+. The analysis uses a data sample of proton-proton collisions at a center-of-mass energy of 13 TeV, collected by the CMS experiment in 2018 and corresponding to an integrated luminosity of 61.6  fb−161.6  fb^{−1}. The fs/fuf_s/f_u ratio is observed to depend on the BB pTp_T and to be consistent with becoming asymptotically constant at large pTp_T. No rapidity dependence is observed. The ratio of the B0B^0 to B+B^+ meson production fractions, fd/fuf_d/f_u, is also measured, for the first time in proton-proton collisions, using the B0→J/ψK∗0B^0→J/ψK^{*0} decay channel. The result is found to be within 1 standard deviation of unity and independent of pTpT and rapidity, as expected from isospin invariance

    Inclusive nonresonant multilepton probes of new phenomena at s\sqrt{s}= 13 TeV

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    An inclusive search for nonresonant signatures of beyond the standard model (SM) phenomena in events with three or more charged leptons, including hadronically decaying τ leptons, is presented. The analysis is based on a data sample corresponding to an integrated luminosity of 138 fb−1^{-1} of proton-proton collisions at s\sqrt{s}= 13 TeV collected by the CMS experiment at the LHC in 2016–2018. Events are categorized based on the lepton and b-tagged jet multiplicities and various kinematic variables. Three scenarios of physics beyond the SM are probed, and signal-specific boosted decision trees are used for enhancing sensitivity. No significant deviations from the background expectations are observed. Lower limits are set at 95% confidence level on the mass of type-III seesaw heavy fermions in the range 845–1065 GeV for various decay branching fraction combinations to SM leptons. Doublet and singlet vectorlike τ lepton extensions of the SM are excluded for masses below 1045 GeV and in the mass range 125–150 GeV, respectively. Scalar leptoquarks decaying exclusively to a top quark and a lepton are excluded below 1.12–1.42 TeV, depending on the lepton flavor. For the type-III seesaw as well as the vectorlike doublet model, these constraints are the most stringent to date. For the vectorlike singlet model, these are the first constraints from the LHC experiments. Detailed results are also presented to facilitate alternative theoretical interpretations

    Search for high-mass exclusive γγ → WW and γγ → ZZ production in proton-proton collisions at s \sqrt{s} = 13 TeV

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