500 research outputs found

    Atypical Work: Who Gets It, and Where Does It Lead? Some U.S. Evidence Using the NLSY79

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    Atypical work arrangements have long been criticized as offering more precarious and lower paid work than regular open-ended employment. In an important paper, Booth et al. (2002) were among the first to recognize that notwithstanding their potential deficiencies, such jobs also functioned as a stepping stone to permanent work. This conclusion proved prescient and has received increasing support in Europe. In the present note, we provide a parallel analysis to Booth et al. for the United States – somewhat of a missing link in the evolving empirical literature – and obtain not dissimilar similar findings for the category of temporary workers as do they for fixed-term contract workers.atypical work, temporary jobs, contracting/consulting work, regular open-ended employment, earnings development

    Atypical Work: Who Gets It, and Where Does It Lead? Some U.S. Evidence Using the NLSY79

    Get PDF
    Atypical work arrangements have long been criticized as offering more precarious and lower paid work than regular open-ended employment. In an important paper published in this journal, Booth et al. (2002) were among the first to recognize that notwithstanding their potential deficiencies, such jobs also functioned as a stepping stone to permanent work. This conclusion proved prescient and has received increasing support in Europe. In the present note, we provide a parallel analysis to Booth et al. for the United States – somewhat of a missing link in the evolving empirical literature – and obtain not dissimilar similar findings for the category of temporary workers as do they for fixed-term contract workers.

    Constraints on the parameters of the Left Right Mirror Model

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    We study some phenomenological constraints on the parameters of a left right model with mirror fermions (LRMM) that solves the strong CP problem. In particular, we evaluate the contribution of mirror neutrinos to the invisible Z decay width (\Gamma_Z^{inv}), and we find that the present experimental value on \Gamma_Z^{inv}, can be used to place an upper bound on the Z-Z' mixing angle that is consistent with limits obtained previously from other low-energy observables. In this model the charged fermions that correspond to the standard model (SM) mix with its mirror counterparts. This mixing, simultaneously with the Z-Z' one, leads to modifications of the \Gamma(Z --> f \bar{f}) decay width. By comparing with LEP data, we obtain bounds on the standard-mirror lepton mixing angles. We also find that the bottom quark mixing parameters can be chosen to fit the experimental values of R_b, and the resulting values for the Z-Z' mixing angle do not agree with previous bounds. However, this disagreement disappears if one takes the more recent ALEPH data.Comment: 7 pages, 2 figures, REVTe

    An effective lagrangian description of charged Higgs decays H^+ -> Wg, WZ and Wh

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    Charged Higgs decays are discussed within an effective lagrangian extension of the two-higgs doublet model, assuming new physics appearing in the Higgs sector of this model. Low energy constrains are used to imposse bounds on certain dimension -six operators that describe the modified charged Higgs interactions. These bounds are used then to study the decays H^+ -> Wg, WZ and Wh, which can have branching ratios of order 10^-5, 10^-1 and O(1), respectively; thse modes are thus sensitive probes of the symmetries of the Higgs sector that could be tested at future colliders.Comment: 15 pages, 3 figure

    New Higgs signals induced by mirror fermion mixing effects

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    We study the conditions under which flavor violation arises in scalar-fermion interactions, as a result of the mixing phenomena between the standard model and exotic fermions. Phenomenological consequences are discussed within the specific context of a left-right model where these additional fermions have mirror properties under the new SU(2)_R gauge group. Bounds on the parameters of the model are obtained from LFV processes; these results are then used to study the LFV Higgs decays (H --> tau l_j, l_j = e, mu), which reach branching ratios that could be detected at future colliders.Comment: 12 pages, 2 figures, ReVTex4, graphicx, to be published in Phys. Rev.

    The Effects of E-Cigarette Taxes on E-Cigarette Prices and Tobacco Product Sales: Evidence from Retail Panel Data

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    We explore the effect of e-cigarette taxes enacted through 2017 in eight states and two large counties on e-cigarette prices, e-cigarette sales, and sales of other tobacco products. We use the Nielsen Retail Scanner data for the years 2011 to 2017, comprising approximately 35,000 retailers nationally. We calculate a Herfindahl–Hirschman Index of 0.251 for retail-based purchases of e-cigarettes, indicating high market concentration. We estimate a tax-to-price pass-through of 1.55 (p \u3c 0.01) and an e-cigarette own-price elasticity of -2.6 (p \u3c 0.01) for the average e-cigarette tax. We also estimate a positive cross-price elasticity of demand for e-cigarettes and traditional cigarettes of roughly 1.1 for the average tax, suggesting that e-cigarettes and traditional cigarettes are economic substitutes. Our results suggest that higher e-cigarette taxes would increase e-cigarette prices and reduce e-cigarette sales, with an unintended effect of increasing traditional cigarette sales. We simulate that for every one standard e-cigarette pod (a device that contains liquid nicotine in e-cigarettes) of 0.7 ml no longer purchased as a result of an e-cigarette tax, the same tax increases traditional cigarettes purchased by 6.2 extra packs

    Lepton flavor violating Higgs boson decays from massive seesaw neutrinos

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    Lepton flavor violating Higgs boson decays are studied within the context of seesaw models with Majorana massive neutrinos. Two models are considered: The SM-seesaw, with the Standard Model Particle content plus three right handed neutrinos, and the MSSM-seesaw, with the Minimal Supersymmetric Standard Model particle content plus three right handed neutrinos and their supersymmetric partners. The widths for these decays are derived from a full one-loop diagrammatic computation in both models, and they are analyzed numerically in terms of the seesaw parameters, namely, the Dirac and Majorana mass matrices. Several possible scenarios for these mass matrices that are compatible with neutrino data are considered. In the SM-seesaw case, very small branching ratios are found for all studied scenarios. These ratios are explained as a consequence of the decoupling behaviour of the heavy right handed neutrinos. In contrast, in the MSSM-seesaw case, sizeable branching ratios are found for some of the leptonic flavor violating decays of the MSSM neutral Higgs bosons and for some choices of the seesaw matrices and MSSM parameters. The relevance of the two competing sources of lepton flavor changing interactions in the MSSM-seesaw case is also discussed. The non-decoupling behaviour of the supersymmetric particles contributing in the loop-diagrams is finally shown.Comment: 44pgs. Version to appear in Phys.Rev.

    Production of neutral scalar Higgs bosons at eγe\gamma colliders

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    We study the production of neutral scalar (CP even) Higgs bosons in the process eγehe\gamma\to e h by including supersymmetric corrections to the dominant tt-channel photon exchange amplitude. In addition to the standard model W±W^{\pm} and fermion loops, there are substantial contributions from chargino loops. For some cases, these contributions can exceed those of the WW's and ordinary fermions. The cross sections in this channel are generally one or two orders of magnitude larger than those in the related channel eeˉγhe\bar{e}\to\gamma h.Comment: 12 pages RevTeX, 5 postscript figures included, uses epsf.st

    The decay Z -> neutrino antineutrino photon in the Standard Model

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    A complete study of the one-loop induced decay Z -> neutrino antineutrino photon is presented within the framework of the Standard Model. The advantages of using a nonlinear gauge are stressed. We have found that the main contributions come from the electric dipole and the magnetic dipole transitions of the Z gauge boson and the neutrino, respectively. We obtain a branching ratio B=7.16E-10, which is about four orders of magnitude smaller than the bound recentely obtained by the L3 collaboration and thus it leaves open a window to search for new physics effects in single-photon decays of the Z boson.Comment: REVTEX,15 pp, 5 eps figures, Approved for publication in Physical Review

    Detection of Neutral MSSM Higgs Bosons at LEP-II and NLC

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    We study the possibility of detecting the neutral Higgs bosons predicted in the Minimal Supersymmetric Standard Model (h0, H0, A0), with the reactions e+ e- --> b b h0 (H0, A0), using the helicity formalism. We analyze the region of parameter space (m_A0-tan beta) where h0(H0, A0) could be detected in the limit when tan beta is large. The numerical computation is done for the energy which is expected to be available at LEP-II (sqrt{s} = 200 GeV) and for a possible Next Linear e+ e- Collider (sqrt{s}=500 GeV).Comment: To be published in Phys.Rev.
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