6,908 research outputs found
Finite Width Effects and Gauge Invariance in Radiative Production and Decay
The naive implementation of finite width effects in processes involving
unstable particles can violate gauge invariance. For the example of radiative
production and decay, , at tree level, it is
demonstrated how gauge invariance is restored by including the imaginary part
of triangle graphs in addition to resumming the imaginary contributions to the
vacuum polarization. Monte Carlo results are presented for the Fermilab
Tevatron.Comment: 10 pages, Revtex, 3 figures submitted separately as uuencoded tarred
postscript files, the complete paper is available at
ftp://phenom.physics.wisc.edu/pub/preprints/1995/madph-95-878.ps.Z or
http://phenom.physics.wisc.edu/pub/preprints/1995/madph-95-878.ps.
Quark resonances and high E_t jets
Possible spin-3/2 quark resonances would have a significant effect on high
E_{\mbox{\rm t}} jet production through their contribution to the subprocess
. Such enhancements are compared to a, recently
reported, anomaly in inclusive jet production at the CDF detector.Comment: 7 pages set in RevTex with four postscript figures appended- all
uuencode
The Charm Content of W+1 Jet Events as a Probe of the Strange Quark Distribution Function
We investigate the prospects for measuring the strange quark distribution
function of the proton in associated plus charm quark production at the
Tevatron. The quark signal produced by strange quark -- gluon fusion,
and , is approximately 5\%
of the inclusive jet cross section for jets with a transverse momentum
~GeV. We study the sensitivity of the plus charm quark cross
section to the parametrization of the strange quark distribution function, and
evaluate the various background processes. Strategies to identify charm quarks
in CDF and D\O \ are discussed. For a charm tagging efficiency of about 10\%
and an integrated luminosity of 30~pb or more, it should be possible to
constrain the strange quark distribution function from production at the
Tevatron.Comment: submitted to Phys. Lett. B, Latex, 12 pages + 4 postscript figures
encoded with uufile, FSU-HEP-930812, MAD/TH/93-6, MAD/PH/788. A postscript
file with text and embedded figures is available via anonymous ftp at
hepsg1.physics.fsu.edu, file is /pub/keller/fsu-hep-930812.p
Higher-order QED corrections to W-boson mass determination at hadron colliders
The impact of higher-order final-state photonic corrections on the precise
determination of the W-boson mass at the Tevatron and LHC colliders is
evaluated. In the presence of realistic selection criteria, the shift in the W
mass from a fit to the transverse mass distribution is found to be about 10 MeV
in the channel and almost negligible in the
channel. The calculation, which is implemented in a Monte Carlo event generator
for data analysis, can contribute to reduce the uncertainty associated to the W
mass measurement at future hadron collider experiments.Comment: 9 pages, 2 figures, 1 table, RevTe
Two Photon Radiation in W and Z Boson Production at the Tevatron Collider
We present a calculation of two photon radiation in W and Z boson production
in hadronic collisions, based on the complete matrix elements for the processes
q\bar q'\to\ell^\pm\nu\gamma\gamma and q\bar q\to\ell^+\ell^-\gamma\gamma,
including finite charged lepton masses. In order to achieve stable numerical
results over the full phase space, multiconfiguration Monte Carlo techniques
are used to map the peaks in the differential cross section. Numerical results
are presented for the Fermilab Tevatron.Comment: Revtex, 28 pages, 3 figure
Z\gamma\gamma production with leptonic decays and triple photon production at NLO QCD
We present a calculation of the O(alpha_s) QCD corrections to the production
of a Z boson in association with two photons and to triple photon production at
hadron colliders. All final-state photons are taken as real. For the Z boson,
we consider the decays both into charged leptons and into neutrinos including
all off-shell effects. Numerical results are obtained via a Monte Carlo program
based on the structure of the VBFNLO program package. This allows us to
implement general cuts and distributions of the final-state particles. We find
that the NLO QCD corrections are sizable and significantly exceed the
expectations from a scale variation of the leading-order result. In addition,
differential distributions of important observables change considerably. The
prediction of two-photon-associated Z production with Z decays into neutrinos
from the charged-lepton rate works well, once we use an additional cut on the
invariant mass of the charged-lepton pair.Comment: 14 pages, 10 figures, 2 table
Vector Boson Pair Production in Hadronic Collisions at Order : Lepton Correlations and Anomalous Couplings
We present cross sections for production of electroweak vector boson pairs,
, and , in and collisions, at next-to-leading
order in . We treat the leptonic decays of the bosons in the
narrow-width approximation, but retain all spin information via decay angle
correlations. We also include the effects of and anomalous
couplings.Comment: 23 pages, 8 figures, 3 table
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