19,827 research outputs found
Colour Reconnection at LEPII
The preliminary results on the search of colour reconnection effects (CR)
from the four experiments at LEP, Aleph, Delphi, L3 and Opal, are reviewed.
Extreme models are excluded by studies of standard variables, and on going
studies of a method first suggested by L3, the particle flow method, are yet
inconclusive.Comment: 8 pages, 6 figures (1 in eps, 5 in ps) talk given at XXXI
International Symposium on Multiparticle Dynamics, Sep. 1-7, 2001, Datong
China URL http://ismd31.ccnu.edu.cn
The Physics of UHECRs: Spectra, Composition and the Transition Galactic-Extragalactic
We review the experimental evidences about flux and mass composition of ultra
high energy cosmic rays in connection with theoretical scenarios concerning
astrophysical sources. In this context, we also address the discussion about
the expected transition between cosmic rays produced inside the Galaxy and
those coming from the intergalactic space.Comment: 6 pages, 10 figures, invited talk given at the "2016 International
Conference on Ultra-High Energy Cosmic Rays (UHECR2016)", Kyoto (Japan),
11-14 October 2016, version accepted for publication on JPS Conference
Proceeding
Battery simulation program
Computer program calculates spacecraft battery energy at specific times dictated by input sequence of recharge, discharge, and no activity phases. Recharge phases are assumed during times not specified, unless batteries are fully charged. Warnings are printed when energy falls below specified level. Program assumes two identical batteries
(Non)Thermal Aspects of Charmonium Production and a New Look at J/ Suppression
To investigate a recent proposal that J/ production in
ultra-relativistic nuclear collisions is of thermal origin we have reanalyzed
the data from the NA38/50 collaboration within a thermal model including charm.
Comparison of the calculated with measured yields demonstrates the non-thermal
origin of hidden charm production at SPS energy. However, the ratio
/(J/ exhibits, in central nucleus-nucleus collisions, thermal
features which lead us to a new interpretation of open charm and charmonium
production at SPS energy. Implications for RHIC and LHC energy measurements
will be discussed.Comment: 12 pages, 3 eps figures, final version with slight corrections, Phys.
Lett. B (in print
B Physics at the Z0 Resonance
B physics results from e+ e- annihilation at the Z0 resonance are reviewed. A
vast program is summarised, including the study of B+, B0d, B0s and b baryon
lifetimes, the time dependence of B0d and B0s oscillations, the width
difference in the B0s system, and the measurements of the magnitudes of the CKM
matrix elements Vcb and Vub.Comment: 17 pages, 8 figures, presented at the UK Phenomenology Workshop on
Heavy Flavour and CP Violation, 17-22 September 200
Spin Alignment of Heavy Meson Revisited
Using heavy quark effective theory a factorized form for inclusive production
rate of a heavy meson can be obtained, in which the nonperturbative effect
related to the heavy meson can be characterized by matrix elements defined in
the heavy quark effective theory. Using this factorization, predictions for the
full spin density matrix of a spin-1 and spin-2 meson can be obtained and they
are characterized only by one coefficient representing the nonperturbative
effect. Predictions for spin-1 heavy meson are compared with experiment
performed at colliders in the energy range from GeV to
GeV, a complete agreement is found for - and -meson.
There are distinct differences from the existing approach and they are
discussed.Comment: 6 pages, Talk given at 3rd Circum-Pan-Pacific Symposium on "High
Energy Spin Physics", Beijing, China, 8-13, 200
A model-independent analysis of the dependence of the anomalous J/psi suppression on the number of participant nucleons
A recently published experimental dependence of the J/psi to Drell-Yan ratio
on the measured, by a zero degree calorimeter, forward energy E_ZDC in Pb+Pb
collisions at the CERN SPS is analyzed. Using a model-independent approach it
is shown that the data are at variance with an earlier published experimental
dependence of the same quantity on the transverse energy of neutral hadrons
E_T. The discrepancy is related to a moderate centrality region: 100 < N_p <
200 (N_p is the number of participant nucleons) and is peculiar only to the
data obtained within the `minimum bias' analysis (using the `theoretical
Drell-Yan'). This could result from systematic experimental errors in the
minimum bias sample. A possible source of the errors is discussed.Comment: 10 pages, LaTeX, 3 PS-figures. V2: Misprints are correcte
Gauge Fluctuations in Superconducting Films
In this paper we consider a superconducting film modeled by the
Ginzburg-Landau model, confined between two parallel planes a distance
apart from one another. Our approach is based on the Gaussian effective
potential in the transverse unitarity gauge, which allows to treat gauge
contributions in a compact form. Using techniques from dimensional and
-function regularizations, modified by the confinement conditions, we
investigate the critical temperature as a function of the film thickness .
The contributions from the scalar self-interaction and from the gauge
fluctuations are clearly identified. The model suggests the existence of a
minimal critical thickness below which superconductivity is suppressed.Comment: 6 pages Revtex, no figure
Fragmentation Function Method for Charge Asymmetry Measurements in \e^+e^- Collisions
We propose a method for measuring the hadron charge asymmetry in \ee
collisions which is based upon the fragmentation function formalism, and is
largely independent of modelling of fragmentation effects. Furthermore, in this
method, QCD radiative corrections can be accounted for in a systematic way.Comment: 11 pages, 4 figures, Latex, CERN-TH.7212/9
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