896 research outputs found
Isolated Photons in Deep Inelastic Scattering
Photon radiation at large transverse momenta at colliders is a detailed probe
of hard interaction dynamics. The isolated photon production cross section in
deep inelastic scattering was measured recently by the ZEUS experiment, and
found to be considerably larger than theoretical predictions obtained with
widely used event generators. To investigate this discrepancy, we perform a
dedicated parton-level calculation of this observable, including contributions
from fragmentation and large-angle radiation. Our results are in good agreement
with all aspects of the experimental measurement.Comment: 4 pages, 3 figure
Matching NLLA+NNLO for event shape distributions
We study the matching of the next-to-leading logarithmic approximation (NLLA)
onto the fixed next-to-next-to-leading order (NNLO) calculation for event shape
distributions in electron-positron annihilation. The resulting theoretical
predictions combine all precision QCD knowledge on the distributions, and are
theoretically reliable over an extended kinematical range. Compared to
previously available matched NLLA+NLO and fixed order NNLO results, we observe
that the effects of the combined NLLA+NNLO are small in the three-jet region,
relevant for precision physics.Comment: 14 pages, 18 figures; typos corrected, published versio
e^+ e^- -> 3 jets and event shapes at NNLO
We report on the calculation of NNLO corrections to the 3-jet cross section
and related event shape distributions in electron-positron annihilation. The
corrections are sizable for all variables, however the magnitude of the
corrections is substantially different for different observables. We observe
that inclusion of the NNLO corrections yields a considerably better agreement
between theory and experimental data both in shape and normalization of the
event shape distributions in the region where the perturbative result is
expected to hold. A new extraction of using the event shape
variables up to NNLO yields a considerably better consistency between the
observables indicating a stabilization of the perturbative corrections at this
order.Comment: Contribution to the Proceedings of the 9th DESY workshop on "Loops
and Legs in Quantum Field Theory", Sondershausen, April 200
Immunotherapeutic targeting of membrane Hsp70-expressing tumors using recombinant human granzyme B
Background: We have previously reported that human recombinant granzyme B (grB) mediates apoptosis in membrane heat shock protein 70 (Hsp70)-positive tumor cells in a perforin-independent manner
Estimation of the Compression Modulus of a Technical Rubber via Cyclic Volumetric Compression Tests
In many applications for ïŹnite element (FE) simulations rubber materials are assumed to be nearly incompressible by applying a high ratio between compression modulus and shear modulus. The compression modulus is commonly given as a constant value in FE analysis. In reality this assumption is not fully correct. InïŹuencing factors like the compressibility of the included ïŹller can lead to a notably change of the compression modulus during mechanical loading. The focus of this work is on the estimation of the cyclic evolution of the compression modulus for a technical ethylene propylene diene rubber (EPDM) by using cyclic volumetric compression tests
Determination of the strong coupling constant based on event shapes
We report on a determination of the strong coupling constant
from a fit of QCD predictions for six event-shape variables, calculated at next-tonext-to-leading order (NNLO) and matched to resummation in the next-to-leadinglogarithmic approximation (NLLA). We use data collected by ALEPH at centre-ofmass energies between 91 and 206 GeV. We also investigate the role of hadronisation
corrections, using both Monte Carlo generator predictions and analytic models to parametrise non-perturbative power corrections
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