502 research outputs found
Atypical Work: Who Gets It, and Where Does It Lead? Some U.S. Evidence Using the NLSY79
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
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
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
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
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
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
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 colliders
We study the production of neutral scalar (CP even) Higgs bosons in the
process by including supersymmetric corrections to the
dominant -channel photon exchange amplitude. In addition to the standard
model and fermion loops, there are substantial contributions from
chargino loops. For some cases, these contributions can exceed those of the
'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
.Comment: 12 pages RevTeX, 5 postscript figures included, uses epsf.st
The decay Z -> neutrino antineutrino photon in the Standard Model
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
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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