48,839 research outputs found
QCD Factorization for Semi-Inclusive Deep-Inelastic Scattering at Low Transverse Momentum
We demonstrate a factorization formula for semi-inclusive deep-inelastic
scattering with hadrons in the current fragmentation region detected at low
transverse momentum. To facilitate the factorization, we introduce the
transverse-momentum dependent parton distributions and fragmentation functions
with gauge links slightly off the light-cone, and with soft-gluon radiations
subtracted. We verify the factorization to one-loop order in perturbative
quantum chromodynamics and argue that it is valid to all orders in perturbation
theory.Comment: 28 pages, figures include
Universality of soft and collinear factors in hard-scattering factorization
Universality in QCD factorization of parton densities, fragmentation
functions, and soft factors is endangered by the process dependence of the
directions of Wilson lines in their definitions. We find a choice of directions
that is consistent with factorization and that gives universality between
e^+e^- annihilation, semi-inclusive deep-inelastic scattering, and the
Drell-Yan process. Universality is only modified by a time-reversal
transformation of the soft function and parton densities between Drell-Yan and
the other processes, whose only effect is the known reversal of sign for T-odd
parton densities like the Sivers function. The modifications of the definitions
needed to remove rapidity divergences with light-like Wilson lines do not
affect the results.Comment: 4 pages. Extra references. Text and references as in published
versio
Renormalization-group anatomy of transverse-momentum dependent parton distribution functions in QCD
The ultraviolet and rapidity divergences of transverse-momentum dependent
parton distribution functions with lightlike and transverse gauge links is
studied, also incorporating a soft eikonal factor. We find that in the
light-cone gauge with -independent pole prescriptions extra divergences
appear which amount, at one-loop, to a cusp-like anomalous dimension. We show
that such contributions are absent when the Mandelstam-Leibbrandt prescription
is used. In the first case, the soft factor cancels the anomalous-dimension
defect, while in the second case its ultraviolet-divergent part reduces to
unity.Comment: 10 pages, 3 figures; needs ws-mpla-hep.cls (supplied). Talk presented
by the first author at Workshop on "Recent Advances in Perturbative QCD and
Hadronic Physics", 20--25 July 2009, ECT*, Trento, Italy, in Honor of Prof.
Anatoly Efremov's 75th birthda
ILR Impact Brief - Pathways to Success: Human Resource Practices Do Matter
[Extract] Most researchers agree that human resource (HR) practices affect attitudes and discretionary behavior on the job and that employee actions and motivations influence company performance. The academic literature also suggests that investing in employees, through high-commitment HR practices such as internal labor markets, selecting new employees who âfitâ the company rather than a particular job, compensating employees on the basis of group and company results, and training and development programs that stress team building and long-term growth, are all indirectly related to organizational success. Missing from the literature is an exploration of the causal mechanisms that mediate between these HR practices and favorable outcomes for companies operating in dynamic environments; this research begins filling the void
Consequences of large impacts on Enceladus' core shape
International audienceThe intense activity on Enceladus suggests a differentiated interior consisting of a rocky core, an internal ocean and an icy mantle. However, topography and gravity data suggests large heterogeneity in the interior, possibly including significant core topography. In the present study, we investigated the consequences of collisions with large impactors on the core shape. We performed impact simulations using the code iSALE2D considering large differentiated impactors with radius ranging between 25 and 100 km and impact velocities ranging between 0.24 and 2.4 km/s. Our simulations showed that the main controlling parameters for the post-impact shape of Enceladusâ rock core are the impactor radius and velocity and to a lesser extent the presence of an internal water ocean and the porosity and strength of the rock core. For low energy impacts, the impactors do not pass completely through the icy mantle. Subsequent sinking and spreading of the impactor rock core lead to a positive core topographic anomaly. For moderately energetic impacts, the impactors completely penetrate through the icy mantle, inducing a negative core topography surrounded by a positive anomaly of smaller amplitude. The depth and lateral extent of the excavated area is mostly determined by the impactor radius and velocity. For highly energetic impacts, the rocky core is strongly deformed, and the full body is likely to be disrupted. Explaining the long-wavelength irregular shape of Enceladusâ core by impacts would imply multiple low velocity (<2.4 km/s) collisions with deca-kilometric differentiated impactors, which is possible only after the LHB period
Relative distributions of W's and Z's at low transverse momenta
Despite large uncertainties in the and transverse momentum
() distributions for q_T\lsim 10 GeV, the ratio of the distributions
varys little. The uncertainty in the ratio of to distributions is
on the order of a few percent, independent of the details of the
nonperturbative parameterization.Comment: 13 pages in revtex, 5 postscript figures available upon request,
UIOWA-94-0
Governance Structures, Voluntary Disclosures and Public Accountability: The Case of UK Higher Education Institutions
Purpose: We investigate the extent of voluntary disclosures in UK higher education institutionsâ (HEIs) annual reports and examine whether internal governance structures influence disclosure in the period following major reform and funding constraints.
Design/methodology/approach: We adopt a modified version of Coy and Dixonâs (2004) public accountability index, referred to in this paper as a public accountability and transparency index (PATI), to measure the extent of voluntary disclosures in 130 UK HEIsâ annual reports. Informed by a multi-theoretical framework drawn from public accountability, legitimacy, resource dependence and stakeholder perspectives, we propose that the characteristics of governing and executive structures in UK universities influence the extent of their voluntary disclosures.
Findings: We find a large degree of variability in the level of voluntary disclosures by universities and an overall relatively low level of PATI (44%), particularly with regards to the disclosure of teaching/research outcomes. We also find that audit committee quality, governing board diversity, governor independence, and the presence of a governance committee are associated with the level of disclosure. Finally, we find that the interaction between executive team characteristics and governance variables enhances the level of voluntary disclosures, thereby providing support for the continued relevance of a âsharedâ leadership in the HEIsâ sector towards enhancing accountability and transparency in HEIs.
Research limitations/implications: In spite of significant funding cuts, regulatory reforms and competitive challenges, the level of voluntary disclosure by UK HEIs remains low. Whilst the role of selected governance mechanisms and âshared leadershipâ in improving disclosure, is asserted, the varying level and selective basis of the disclosures across the surveyed HEIs suggest that the public accountability motive is weaker relative to the other motives underpinned by stakeholder, legitimacy and resource dependence perspectives.
Originality/value: This is the first study which explores the association between HEI governance structures, managerial characteristics and the level of disclosure in UK HEIs
Factorization in hard diffraction
In this talk, I reviewed the role of factorization in diffraction hard
scattering.Comment: Talk presented at the Ringberg Workshop on ``New Trends in HERA
Physics 2001''. 10 pages, 6 postscript figures. Misprints correcte
Catalytic Oxidation of Styrene in the Presence of Square Planar Cobalt(iii) Complexes of Polyanionic Chelating Ligands
Styrene has been catalytically oxidised in the presence of iodosoarenes and square planar cobalt(iii) complexes of
polyanionic chelating (PAC) ligands; possible intermediates in these oxygen atom transfer reactions include cobalt(v)-oxo complexes
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