34,874 research outputs found
Impacts of team virtuality on performance : a qualitative study.
Recent studies on virtual teams reveal that team virtuality varies in a continuum and may take different levels. Different levels of virtuality have considerable impacts on team processes and management as they imply several characteristics concerning communication dynamics and interaction styles, which change when shifting from one level to another. The purpose of this paper is to assess how the variability of team virtuality influences team performance. A multidimensional approach to evaluate virtuality was elaborated to identify changing performance variables at each level. The performance variables retained with relevance to the context study are: output quality, team members` satisfaction, and team processes. A qualitative study was conducted on 6 virtual teams composed of 4 students involved in on-line master degrees at a French university. The results show that performance measures are differently influenced by virtuality level. Although output quality seems not to be related to team virtuality, effective team processes and members’ satisfaction are associated with low virtuality levels. Ineffective processes were found in high virtuality teams, however positive dynamics and tem spirit characterise low virtuality teams.Télétravail; Virtual team performance; Team processes; performance; Equipes virtuelles; E-management; Telework;
On the transverse momentum in Z-boson production in a virtuality ordered parton shower
Cross sections for physical processes that involve very different momentum
scales in the same process will involve large logarithms of the ratio of the
momentum scales when calculated in perturbation theory. One goal of
calculations using parton showers is to sum these large logarithms. We ask
whether this goal is achieved for the transverse momentum distribution of a
Z-boson produced in hadron-hadron collisions when the shower is organized with
higher virtuality parton splittings coming first, followed successively by
lower virtuality parton splittings. We find that the virtuality ordered shower
works well in reproducing the known QCD result.Comment: 60 pages with three figure
Universality near zero virtuality
In this paper we study a random matrix model with the chiral and flavor
structure of the QCD Dirac operator and a temperature dependence given by the
lowest Matsubara frequency. Using the supersymmetric method for random matrix
theory, we obtain an exact, analytic expression for the average spectral
density. In the large-n limit, the spectral density can be obtained from the
solution to a cubic equation. This spectral density is non-zero in the vicinity
of eigenvalue zero only for temperatures below the critical temperature of this
model. Our main result is the demonstration that the microscopic limit of the
spectral density is independent of temperature up to the critical temperature.
This is due to a number of `miraculous' cancellations. This result provides
strong support for the conjecture that the microscopic spectral density is
universal. In our derivation, we emphasize the symmetries of the partition
function and show that this universal behavior is closely related to the
existence of an invariant saddle-point manifold.Comment: 23 pages, Late
Dead cone due to parton virtuality
A general expression for the dead cone of gluons radiated by virtual partons
has been derived. The conventional dead cone for massive on-shell quarks and
the dead cone for the massless virtual partons have been obtained by using
different limits of the general expression. Radiative suppression due to the
virtuality of initial parton jets in Heavy-Ion Collisions (HIC) has been
discussed. It is observed that the suppression caused by the high virtuality is
overwhelmingly large as compared to that on account of conventional dead-cone
of heavy quarks. The dead cone due to virtuality may play a crucial role in
explaining the observed similar suppression patterns of light and heavy quarks
jets in heavy ion collisions at Relativistic Heavy Ion Collider (RHIC)
The structure functions of longitudinal virtual photon at low virtualities
The structure functions of longitudinal virtual photon at low virtualities
are calculated in the framework of chiral pertubation theory(ChPT) in the zero
and first order of ChPT. It is assumed that the virtuality of target
longitudinal photon is much less than the virtuality of the hard projectile
photon and both are less than the characteristic ChPT scale.Comment: 16 pages, 8 figure
The Quark Beam Function at Two Loops
In differential measurements at a hadron collider, collinear initial-state
radiation is described by process-independent beam functions. They are the
field-theoretic analog of initial-state parton showers. Depending on the
measured observable they are differential in the virtuality and/or transverse
momentum of the colliding partons in addition to the usual longitudinal
momentum fraction. Perturbatively, the beam functions can be calculated by
matching them onto standard quark and gluon parton distribution functions. We
calculate the inclusive virtuality-dependent quark beam function at NNLO, which
is relevant for any observables probing the virtuality of the incoming partons,
including N-jettiness and beam thrust. For such observables, our results are an
important ingredient in the resummation of large logarithms at N3LL order, and
provide all contributions enhanced by collinear t-channel singularities at NNLO
for quark-initiated processes in analytic form. We perform the calculation in
both Feynman and axial gauge and use two different methods to evaluate the
discontinuity of the two-loop Feynman diagrams, providing nontrivial checks of
the calculation. As part of our results we reproduce the known two-loop QCD
splitting functions and confirm at two loops that the virtuality-dependent beam
and final-state jet functions have the same anomalous dimension.Comment: 27 pages, 3 figures; v2: journal versio
The Gluon Beam Function at Two Loops
The virtuality-dependent beam function is a universal ingredient in the
resummation for observables probing the virtuality of incoming partons,
including N-jettiness and beam thrust. We compute the gluon beam function at
two-loop order. Together with our previous results for the two-loop quark beam
function, this completes the full set of virtuality-dependent beam functions at
next-to-next-to-leading order (NNLO). Our results are required to account for
all collinear ISR effects to the N-jettiness event shape through N^3LL order.
We present numerical results for both the quark and gluon beam functions up to
NNLO and N^3LL order. Numerically, the NNLO matching corrections are important.
They reduce the residual matching scale dependence in the resummed beam
function by about a factor of two.Comment: 21 pages, 6 figures; v2: journal versio
Structure of Real and Virtual Photons from ZEUS
Measurements sensitive to the structure of both real and virtual photons are
presented and compared to theoretical models with various photon parton
distribution functions (PDFs). Measurements for real photons show a tendency
for the available photon PDFs to be too small to describe the data. For virtual
photons, the photon PDF is seen to decrease with increasing photon virtuality.
In order to describe the data, resolved photon processes are required up to a
photon virtuality of at least 4.5 GeV^2
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