2,975 research outputs found
Drell-Yan processes with WINHAC
We present the Monte Carlo event generator WINHAC for Drell-Yan processes in
proton-proton, proton-antiproton, proton-ion and ion-ion collisions. It
features multiphoton radiation within the Yennie-Frautschi-Suura exclusive
exponentiation scheme with O(alpha) electroweak corrections for the
charged-current (W+/W-) processes and multiphoton radiation generated by PHOTOS
for neutral-current (Z+gamma) ones. For the initial-state QCD/QED parton shower
and hadronisation it is interfaced with PYTHIA. It includes several options,
e.g. for the polarized W-boson production, generation of weighted/unweighted
events, etc. WINHAC was cross-checked numerically at the per-mille level with
independent Monte Carlo programs, such as HORACE and SANC. It has been used as
a basic tool for developing and testing some new methods of precise
measurements of the Standard Model parameters at the LHC, in particular the
W-boson mass. Recently, it has been applied to simulations of double Drell-Yan
processes resulting from double-parton scattering, in order to assess their
influence on the Higgs-boson detection at the LHC in its ZZ and W+W- decay
channels.Comment: 8 pages; presented at the XXXVII International Conference of
Theoretical Physics "Matter To The Deepest", Ustron, Poland, 1-6 September
2013; to appear in Acta Physica Polonica
Measuring sigma(e^+e^- \to hadrons) using tagged photon
We propose to use events with radiated photons in e^+e^- collisions to
measure the total cross section of e^+ e^- \to hadrons as a function of the
center of mass energy. The Monte Carlo simulation for the collider DAPHNE shows
that a competitive accuracy can be achieved with this method.Comment: revtex, 13 page
Z-boson as "the standard candle" for high precision W-boson physics at LHC
In this paper we propose a strategy for measuring the inclusive W-boson
production processes at LHC. This strategy exploits simultaneously the unique
flexibility of the LHC collider in running variable beam particle species at
variable beam energies, and the configuration flexibility of the LHC detectors.
We propose their concrete settings for a precision measurement of the Standard
Model parameters. These dedicated settings optimise the use of the Z boson and
Drell-Yan pair production processes as ``the standard reference candles''. The
presented strategy allows to factorise and to directly measure those of the QCD
effects which affect differently the W and Z production processes. It reduces
to a level of 10^{-4} the impact of uncertainties in the partonic distribution
functions (PDFs) and in the transverse momentum of the quarks on the
measurement precision. Last but not the least, it reduces by a factor of 10 an
impact of systematic measurement errors, such as the energy scale and the
measurement resolution, on the W-boson production observables.Comment: 20 pages, 4 figure
Measurement of MW+ - MW- at LHC
This paper is the second of the series of papers proposing dedicated
strategies for precision measurements of the Standard Model parameters at the
LHC. The common feature of these strategies is their robustness with respect to
the systematic measurement and modeling error sources. Their impact on the
precision of the measured parameters is reduced using dedicated observables and
dedicated measurement procedures which exploit flexibilities of the collider
and detector running modes. In the present paper we focus our attention on the
measurement of the charge asymmetry of the W-boson mass. This measurement is of
primordial importance for the LHC experimental program, both as a direct test
of the charge-sign-independent coupling of the W-bosons to the matter particles
and as a necessary first step towards the precision measurement of the
charge-averaged W-boson mass. We propose and evaluate the LHC-specific strategy
to measure the mass difference between the positively and negatively charged
W-bosons, MW+ - MW-. We show that its present precision can be improved at the
LHC by a factor of 20. We argue that such a precision is beyond the reach of
the standard measurement and calibration methods imported to the LHC from the
Tevatron program.Comment: 39 pages, 8 figure
Analysis of adenoviral attachment to human platelets
<p>Abstract</p> <p>Background</p> <p>Systemic adenoviral (Ad) vector administration is associated with thrombocytopenia. Recently, Ad interaction with mouse platelets emerged as a key player determining liver uptake and platelet clearance. However, whether Ad can activate platelets is controversial. Thus, <it>in vitro </it>analysis of Ad attachment to platelets is of interest.</p> <p>Methods</p> <p>We developed a direct flow cytometry assay to specifically detect Ad particles adherent to human platelets. The method was pre-validated in nucleated cells. Blocking assays were employed to specifically inhibit Ad attachment to platelets. Platelet activation was analyzed using annexin v flow cytometry.</p> <p>Results</p> <p>We found <it>in vitro </it>that Ad binding to human platelets is synergistically enhanced by the combination of platelet activation by thrombin and MnCl2 supplementation. Of note, Ad binding could activate human platelets. Platelets bound Ad displaying an RGD ligand in the fiber knob more efficiently than unmodified Ad. In contrast to a previous report, CAR expression was not detected on human platelets. Integrins appear to mediate Ad binding to platelets, at least partially. Finally, αIIbβ3-deficient platelets from a patient with Glanzmann thrombasthenia could bind Ad 5-fold more efficiently than normal platelets.</p> <p>Conclusion</p> <p>The flow cytometry methodology developed herein allows the quantitative measurement of Ad attachment to platelets and may provide a useful <it>in vitro </it>approach to investigate Ad interaction with platelets.</p
Tagged-photon events in polarized DIS process
Deep-inelastic events for the scattering of the longitudinally polarized
electron by polarized proton with tagged collinear photon radiated from
initial-state electron are considered. The corresponding cross-section is
derived in the Born approximation. The model-independent radiative corrections
to the Born cross-section are also calculated. Obtained result is applied to
the case of elastic scattering.Comment: 14 pages, 2 figures, submitted to JET
- …