3,978 research outputs found
Multiplicity Fluctuations and Bose-Einstein Correlations in DIS at HERA
Results of the recent studies of the multiplicity fluctuations and
Bose-Einstein correlations (BEC) in deep-inelastic scattering (DIS) at large
Q are reviewed. The measurements were done with the ZEUS detetor at HERA.Comment: 4 pages, 3 figures in eps, talk given at XXXI International Symposium
on Multiparticle Dynamics, Sept 1-7, 2001, Datong China. URL
http://202.114.35.18
Search for Pentaquarks at BABAR
The results of searches for the strange pentaquark states, Theta(1540)+,
Xi(1860)-- and Xi(1860)0 in data recorded by the BABAR experiment are
presented. We search for these three states inclusively in 123.4 fb^-1 of e+ e-
annihilation data produced at the PEP-II asymmetric storage rings; we find no
evidence for their production in any physics process, and set limits on their
production rates that are well below the measured rates for conventional
baryons. We also search for Theta(1540)+ produced in interactions of electrons
or hadrons in the material of the inner part of the detector. No evidence for
this state is found in a sample with much higher statistics than similar
electroproduction experiments that claim a signal.Comment: 4 pages, 4 postscript figues, contributed to the Proceedings of QCD
05, Montpellie
Photoproduction of Xi off nucleons
The photoproduction reaction is investigated based on
a relativistic meson-exchange model of hadronic interactions. The production
amplitude is calculated in the tree-level approximation from relevant effective
Lagrangians, whose (coupling constant) parameters are mostly fixed from the
empirical data and/or quark models together with SU(3) symmetry considerations.
Gauge invariance of the resulting amplitude is maintained by introducing the
contact currents by extending the gauge-invariant approach of Haberzettl for
one-meson photoproduction to two-meson photoproduction. The role of the
intermediate low-lying hyperons and of the intermediate higher-mass hyperon
resonances are analyzed in detail. In particular, the basic features of the
production of in and their possible
manifestations in the forthcoming experimental data are discussed.Comment: 18 pages, 17 figures, REVTeX, 1 figure added, to appear in Phys. Rev.
Heavy flavour production in DGLAP improved saturation model
The charm and beauty quark production in deep inelastic scattering at low
values of the Bjorken variable x is considered in the DGLAP improved saturation
model. After fitting parameters of the model to the structure function F_2, the
heavy quark contributions Fc_2 and Fb_2 are predicted. A good description of
the data is found. Predictions for the longitudinal structure function F_L and
the diffractive structure function FD_2 are also presented.Comment: 16 pages, 7 figures; typos corrected, references added, final
Phys.Rev. D versio
Mean curvature flow of monotone Lagrangian submanifolds
We use holomorphic disks to describe the formation of singularities in the
mean curvature flow of monotone Lagrangian submanifolds in .Comment: 37 pages, 3 figure
QCD at high energy (experiments)
Recent measurements of QCD interactions involving large momentum transfers
are reviewed. The status of measurements of the strong coupling constant is
summarised. Recent developments in the measurement and interpretation of deep
inelastic scattering, proton-anti-proton collisions and two-photon processes
are discussed. While QCD at next-to-leading order gives a qualitative
description of many processes, next-to-NLO calculations are now required to
allow quantitative information to be extracted from hadron-initiated multijet
data. This is illustrated by a discussion of recent data on the photoproduction
of dijet events at HERA.Comment: Talk presented at the International Conference on High
Energy Physics, Amsterdam, 24-31 July 2002. 18 pages, 30 figure
Selection and reconstruction of the top quarks in the all-hadronic decays at a Linear Collider
A method of reconstruction of the top quarks produced in the process E+E- ->
t\bar{t} -> 6 jets at a Linear Collider (LC) is proposed. The approach does not
involve a kinematic fit, as well as assumptions on the invariant masses of the
dijets originating from the decays of W bosons and, therefore, the method is
expected to be less sensitive to theoretical and experimental uncertainties on
the top-mass measurement than traditional reconstruction methods. For the first
time, the reconstruction of the top quarks was investigated using the full LC
detector simulation after taking into account the background arising from QCD
multi-jet production.Comment: 22 pages, including 13 figures and 3 table
Color Glass Condensate and BFKL dynamics in deep inelastic scattering at small x
The proton structure function F_2(x,Q^2) for x < 0.01 and 0.045< Q^2 < 45
GeV^2, measured in the deep inelastic scattering at HERA, can be well described
within the framework of the Color Glass Condensate.Comment: 4 pages, 1 figure, incl. IOP style files. Talk given at the 17th
International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions
(Quark Matter 2004), Oakland, CA USA, 11-17 Jan 200
On direct measurement of the W production charge asymmetry at the LHC
The prospects for making a direct measurement of the W production charge
asymmetry at the LHC are discussed. A modification to the method used at the
Tevatron is proposed for measurements at the LHC. The expected sensitivity for
such a measurement to parton distribution functions is compared to that for a
measurement of the lepton charge asymmetry. The direct measurement approach is
found to be less useful for placing constraints on parton distribution
functions at the LHC than a measurement of the lepton charge asymmetry.Comment: 18 pages, 10 figures, v2: references and keywords updated v3:
Additional paragraph discussing inclusion of W asymmetry in global fits adde
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