341 research outputs found
Charmonia production from -hadron decays at LHC with -factorization: , and
We consider the production of and mesons originating from
the decays of -flavored hadrons at the LHC using the -factorization
approach. Our analysis covers both inclusive charmonia production and
production of mesons in association with bosons. We apply the
transverse momentum dependent (or unintegrated) gluon density in a proton
derived from Catani-Ciafaloni-Fiorani-Marchesini (CCFM) evolution equation and
adopt fragmentation functions based on the non-relativistic QCD factorization
to describe the inclusive -hadron decays into the different charmonium
states. Our predictions agree well with latest experimental data taken by the
CMS, ATLAS and LHCb Collaborations at , and ~TeV. The
contributions from double parton scattering to the associated non-prompt
production are estimated and found to be small.Comment: 12 pages, 5 figure
Measurements of the QCD Colour Factors at LEP
A summary of the measurements of the QCD colour factors at LEP is presented.
Such measurements provide a test of the gauge group structure underlying the
theory of strong interactions. A variety of methods have been applied by the
various experiments, and perfect consistency with the expectation of QCD with
SU(3) as gauge group is found.Comment: 9 pages, Latex, Talk presented at the 5th Topical Seminar on The
Irresistible Rise of the Standard Model, San Miniato, Italy, April 199
Measurement of optical to electrical and electrical to optical delays with ps-level uncertainty
We present a new measurement principle to determine the absolute time delay
of a waveform from an optical reference plane to an electrical reference plane
and vice versa. We demonstrate a method based on this principle with 2 ps
uncertainty. This method can be used to perform accurate time delay
determinations of optical transceivers used in fibre-optic time-dissemination
equipment. As a result the time scales in optical and electrical domain can be
related to each other with the same uncertainty. We expect this method to break
new grounds in high-accuracy time transfer and absolute calibration of
time-transfer equipment
Contribution of through the QCD anomaly in exclusive decays and
We compute the decay rates for the exclusive decays and in a QCD-improved factorization framework by including the
contribution from the process through
the QCD anomaly. This method provides an alternative estimate of the
contribution to these decays as
compared to the one using the intrinsic charm content of the
and mesons determined through the decays . The resulting branching ratios are compared with the CLEO
data on and
and predictions are made for the rest.Comment: 16 pages including 4 postscript figures; uses epsfig. The most recent
branching ratios from CLEO, ref. [5], are taken into account. The theory part
is unchange
Asymmetric Uncertainties: Sources, Treatment and Potential Dangers
The issue of asymmetric uncertainties resulting from fits, nonlinear
propagation and systematic effects is reviewed. It is shown that, in all cases,
whenever a published result is given with asymmetric uncertainties, the value
of the physical quantity of interest is biased with respect to what would be
obtained using at best all experimental and theoretical information that
contribute to evaluate the combined uncertainty. The probabilistic solution to
the problem is provided both in exact and in approximated forms.Comment: 21 pages, 5 figures. improved version with some corrections,
additional remarks and references (download of new version is recommended).
This paper and related work are also available at
http://www.roma1.infn.it/~dagos/prob+stat.htm
Associated non-prompt and production at LHC as a test for TMD gluon density
We consider the associated production of mesons and muons
originating from the -flavored hadron decays and non-prompt double
production at the LHC using the -factorization approach. To describe the
inclusive -hadron decays into the different charmonium states we apply
fragmentation approach and adopt fragmentation functions based on the
non-relativistic QCD factorization. The transverse momentum dependent (TMD)
gluon densities in a proton are determined using the
Catani-Ciafaloni-Fiorani-Marchesini equation and Kimber-Martin-Ryskin
prescription. We investigate the effects coming from parton showers, estimate
the double parton scattering contribution and compare our predictions with the
first experimental data taken by the ATLAS and LHCb Collaborations at ~TeV. These data can serve as an additional test for TMD gluon density
function in a proton.Comment: 14 pages, 12 figure
Closing the light gluino window
The running of the strong coupling constant, and is
studied on the three-loop level. Based on experimental data of
and and the LEP multijet analysis, the light gluino scenario is
excluded to 99.97% CL (window I) and 99.89% CL (window III).Comment: 7 pages, 6 figures, talk at HEP97, Jerusale
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