173 research outputs found
Perceived organizational support and organizational identification : joint moderating effects of employee exchange ideology and employee investment
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
Threshold corrections to the running of gauge couplings are calculated for
superstring models with free complex world sheet fermions. For two N=1
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 model to the gauge group
. 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
Uplifted supersymmetric Higgs region
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 quark and decay predominantly into
\tau^+\tau^- or \tau\nu.Comment: 14 pages; Signs in Eqns. (3.1) and (4.2) corrected, appendix include
Adult attachment style across individuals and role-relationships: Avoidance is relationship-specific, but anxiety shows greater generalizability
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
Bottom-Tau Unification in SUSY SU(5) GUT and Constraints from b to s gamma and Muon g-2
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
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
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 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 beyond the
GUT scale, and that additional renormalization group running takes place
between and 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 (1160) GeV can be probed
with 10 (100) fb of integrated luminosity, corresponding to a reach in
terms of of 2150 (2500) GeV. The inoMSB model and mSUGRA can likely
only be differentiated at a linear 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
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
For large values of the minimal supergravity model parameter , the
tau lepton and the bottom quark Yukawa couplings become large, leading to
reduced masses of -sleptons and -squarks relative to their first and
second generation counterparts, and to enhanced decays of charginos and
neutralinos to -leptons and -quarks. We evaluate the reach of the CERN
LHC collider for supersymmetry in the mSUGRA model parameter space. We
find that values of GeV can be probed with just 10
fb of integrated luminosity for values as high as 45, so
that mSUGRA cannot escape the scrutiny of LHC experiments by virtue of having a
large value of . We also perform a case study of an mSUGRA model at
where \tz_2\to \tau\ttau_1 and \tw_1\to \ttau_1\nu_\tau
with 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 there
can be an observable excess of leptons, and argue that 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
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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