173 research outputs found

    Perceived organizational support and organizational identification : joint moderating effects of employee exchange ideology and employee investment

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    Organizational identification (OID) can be developed out of social exchange practices within an organizational setting. Drawing on social exchange theory, we propose that the effect of perceived organizational support (POS) on OID is stronger for employees with stronger exchange ideology. We further argue that employee investment in an organization may also create a social exchange process that positively influences OID. We expect that employee investment moderates not only the effect of POS on OID, but also the enhancing effect of exchange ideology on the effect of POS on OID. Specifically, POS has a stronger positive effect on OID when exchange ideology is high and when employee investment is low. When employee investment is high, POS has a weaker effect on OID regardless of employees’ exchange ideology. These effects were empirically supported by a survey. Theoretical and practical implications are also discussed

    Threshold Corrections and Gauge Symmetry in Twisted Superstring Models

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    Threshold corrections to the running of gauge couplings are calculated for superstring models with free complex world sheet fermions. For two N=1 SU(2)×U(1)5SU(2)\times U(1)^5 models, the threshold corrections lead to a small increase in the unification scale. Examples are given to illustrate how a given particle spectrum can be described by models with different boundary conditions on the internal fermions. We also discuss how complex twisted fermions can enhance the symmetry group of an N=4 SU(3)×U(1)×U(1)SU(3)\times U(1)\times U(1) model to the gauge group SU(3)×SU(2)×U(1)SU(3)\times SU(2)\times U(1). It is then shown how a mixing angle analogous to the Weinberg angle depends on the boundary conditions of the internal fermions.Comment: easier to Tex version, figures to be sent separatel

    Adult attachment style across individuals and role-relationships: Avoidance is relationship-specific, but anxiety shows greater generalizability

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    A generalisability study examined the hypotheses that avoidant attachment, reflecting the representation of others, should be more relationship-specific (vary across relationships more than across individuals), while attachment anxiety, reflecting self-representation, should be more generalisable across a person’s relationships. College students responded to 6-item questionnaire measures of these variables for 5 relationships (mother, father, best same-gender friend, romantic partner or best opposite-gender friend, other close person), on 3 (N = 120) or 2 (N = 77) occasions separated by a few weeks. Results supported the hypotheses, with the person variance component being larger than the relationship-specific component for anxiety, and the opposite happening for avoidance. Anxiety therefore seems not to be as relationship-specific as previous research suggested. Possible reasons for discrepancies between the current and previous studies are discussed

    Uplifted supersymmetric Higgs region

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    We show that the parameter space of the Minimal Supersymmetric Standard Model includes a region where the down-type fermion masses are generated by the loop-induced couplings to the up-type Higgs doublet. In this region the down-type Higgs doublet does not acquire a vacuum expectation value at tree level, and has sizable couplings in the superpotential to the tau leptons and bottom quarks. Besides a light standard-like Higgs boson, the Higgs spectrum includes the nearly degenerate states of a heavy spin-0 doublet which can be produced through their couplings to the bb quark and decay predominantly into \tau^+\tau^- or \tau\nu.Comment: 14 pages; Signs in Eqns. (3.1) and (4.2) corrected, appendix include

    Bottom-Tau Unification in SUSY SU(5) GUT and Constraints from b to s gamma and Muon g-2

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    An analysis is made on bottom-tau Yukawa unification in supersymmetric (SUSY) SU(5) grand unified theory (GUT) in the framework of minimal supergravity, in which the parameter space is restricted by some experimental constraints including Br(b to s gamma) and muon g-2. The bottom-tau unification can be accommodated to the measured branching ratio Br(b to s gamma) if superparticle masses are relatively heavy and higgsino mass parameter \mu is negative. On the other hand, if we take the latest muon g-2 data to require positive SUSY contributions, then wrong-sign threshold corrections at SUSY scale upset the Yukawa unification with more than 20 percent discrepancy. It has to be compensated by superheavy threshold corrections around the GUT scale, which constrains models of flavor in SUSY GUT. A pattern of the superparticle masses preferred by the three requirements is also commented.Comment: 21pages, 6figure

    Strongly Coupled Grand Unification in Higher Dimensions

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    We consider the scenario where all the couplings in the theory are strong at the cut-off scale, in the context of higher dimensional grand unified field theories where the unified gauge symmetry is broken by an orbifold compactification. In this scenario, the non-calculable correction to gauge unification from unknown ultraviolet physics is naturally suppressed by the large volume of the extra dimension, and the threshold correction is dominated by a calculable contribution from Kaluza-Klein towers that gives the values for \sin^2\theta_w and \alpha_s in good agreement with low-energy data. The threshold correction is reliably estimated despite the fact that the theory is strongly coupled at the cut-off scale. A realistic 5d supersymmetric SU(5) model is presented as an example, where rapid d=6 proton decay is avoided by putting the first generation matter in the 5d bulk.Comment: 17 pages, latex, to appear in Phys. Rev.

    The Reach of the Fermilab Tevatron and CERN LHC for Gaugino Mediated SUSY Breaking Models

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    In supersymmetric models with gaugino mediated SUSY breaking (inoMSB), it is assumed that SUSY breaking on a hidden brane is communicated to the visible brane via gauge superfields which propagate in the bulk. This leads to GUT models where the common gaugino mass m1/2m_{1/2} is the only soft SUSY breaking term to receive contributions at tree level. To obtain a viable phenomenology, it is assumed that the gaugino mass is induced at some scale McM_c beyond the GUT scale, and that additional renormalization group running takes place between McM_c and MGUTM_{GUT} as in a SUSY GUT. We assume an SU(5) SUSY GUT above the GUT scale, and compute the SUSY particle spectrum expected in models with inoMSB. We use the Monte Carlo program ISAJET to simulate signals within the inoMSB model, and compute the SUSY reach including cuts and triggers approriate to Fermilab Tevatron and CERN LHC experiments. We find no reach for SUSY by the Tevatron collider in the trilepton channel. %either with or without %identified tau leptons. At the CERN LHC, values of m1/2=1000m_{1/2}=1000 (1160) GeV can be probed with 10 (100) fb1^{-1} of integrated luminosity, corresponding to a reach in terms of mtgm_{\tg} of 2150 (2500) GeV. The inoMSB model and mSUGRA can likely only be differentiated at a linear e+ee^+e^- collider with sufficient energy to produce sleptons and charginos.Comment: 17 page revtex file with 9 PS figure

    Dispersive properties of quasi-phase-matched optical parametric amplifiers

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    The dispersive properties of non-degenerate optical parametric amplification in quasi-phase-matched (QPM) nonlinear quadratic crystals with an arbitrary grating profile are theoretically investigated in the no-pump-depletion limit. The spectral group delay curve of the amplifier is shown to be univocally determined by its spectral power gain curve through a Hilbert transform. Such a constraint has important implications on the propagation of spectrally-narrow optical pulses through the amplifier. In particular, it is shown that anomalous transit times, corresponding to superluminal or even negative group velocities, are possible near local minima of the spectral gain curve. A possible experimental observation of such effects using a QPM Lithium-Niobate crystal is suggested.Comment: submitted for publicatio

    Probing Minimal Supergravity at the CERN LHC for Large tanβ\tan\beta

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    For large values of the minimal supergravity model parameter tanβ\tan\beta, the tau lepton and the bottom quark Yukawa couplings become large, leading to reduced masses of τ\tau-sleptons and bb-squarks relative to their first and second generation counterparts, and to enhanced decays of charginos and neutralinos to τ\tau-leptons and bb-quarks. We evaluate the reach of the CERN LHC pppp collider for supersymmetry in the mSUGRA model parameter space. We find that values of mtg15002000m_{\tg}\sim 1500-2000 GeV can be probed with just 10 fb1^{-1} of integrated luminosity for tanβ\tan\beta values as high as 45, so that mSUGRA cannot escape the scrutiny of LHC experiments by virtue of having a large value of tanβ\tan\beta. We also perform a case study of an mSUGRA model at tanβ=45\tan\beta =45 where \tz_2\to \tau\ttau_1 and \tw_1\to \ttau_1\nu_\tau with 100\sim 100% branching fraction. In this case, at least within our simplistic study, we show that a di-tau mass edge, which determines the value of m_{\tz_2}-m_{\tz_1}, can still be reconstructed. This information can be used as a starting point for reconstructing SUSY cascade decays on an event-by-event basis, and can provide a strong constraint in determining the underlying model parameters. Finally, we show that for large tanβ\tan\beta there can be an observable excess of τ\tau leptons, and argue that τ\tau signals might serve to provide new information about the underlying model framework.Comment: 22 page REVTEX file including 8 figure

    Improved full one-loop corrections to A^0 -> \sf_1 \sf_2 and \sf_2 -> \sf_1 A^0

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    We calculate the full electroweak one-loop corrections to the decay of the CP-odd Higgs boson A^0 into scalar fermions in the minimal supersymmetric extension of the Standard Model. For this purpose many parameters of the MSSM have to be properly renormalized in the on-shell renormalization scheme. We have also included the SUSY-QCD corrections. For the decay into bottom squarks and tau sleptons, especially for large \tan\b, the corrections can be very large making the perturbation expansion unreliable. We solve this problem by an appropriate definition of the tree-level coupling in terms of running fermion masses and running trilinear couplings A_f. We also discuss the decay of heavy scalar fermions into light scalar fermions and A^0. We find that the corrections can be sizeable and therefore cannot be neglected.Comment: 42 pages, 20 figures (23 eps-files
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