413 research outputs found
Structure Functions of Nuclei at Small x and Diffraction at HERA
Gribov theory is applied to investigate the shadowing effects in the
structure functions of nuclei. In this approach these effects are related to
the process of diffractive dissociation of a virtual photon. A model for this
diffractive process, which describes well the HERA data, is used to calculate
the shadowing in nuclear structure functions. A reasonable description of the
x, Q^2 and A-dependence of nuclear shadowing is achieved.Comment: TeX, 10 pages, 7 figures in 6 ps-file
Hard Diffraction at HERA and the Gluonic Content of the Pomeron
We show that the previously introduced CKMT model, based on conventional
Regge theory, gives a good description of the HERA data on the structure
function F_2^D for large rapidity gap (diffractive) events. These data allow,
not only to determine the valence and sea quark content of the Pomeron, but
also, through their Q^2 dependence, give information on its gluonic content.
Using DGLAP evolution, we find that the gluon distribution in the Pomeron is
very hard and the gluons carry more momentum than the quarks. This indicates
that the Pomeron, unlike ordinary hadrons, is a mostly gluonic object. With our
definition of the Pomeron flux factor the total momentum carried by quarks and
gluons turns out to be 0.3-0.4 - strongly violating the momentum sum rule.Comment: C-Shell archive of a PostScript file containing a 20 page paper with
text and 12 figures in i
Strange Baryon Production in Heavy Ion Collisions
The rapidity distribution of and produced in
nucleus-nucleus collisions at CERN energies is studied in the framework of an
independent string model - with quark-antiquark as well as diquark-antidiquark
pairs in the nucleon sea. It is shown that, besides the
- pair production resulting from the fragmentation of
sea diquarks, final state interactions of co-moving secondaries and are needed in order to
reproduce the data. Predictions for - collisions are presented.Comment: Plain TeX + epsf, 40 pages; 1 Postscript-table and 7 Postscript
figures (uuencoded
Diffractive Dissociation in Deep Inelastic Scattering at HERA
The diffraction dissociation of virtual photons is considered in the
framework of conventional Regge theory. It is shown that the recent HERA data
on large rapidity gap events can be successfully described in terms of the
Pomeron structure function. Using Regge factorization, the latter can be
related to the deuteron structure function. The parameters which relate these
two structure functions are determined from soft hadronic diffraction data. The
size of the shadowing corrections at low x and large Q**2 is also obtained.Comment: 17 pages, TEX, preprint LPTHE Orsay 94-4
Production Associated to Rare Events in High Energy Hadron-Hadron Collisions
At very high energy the same universal relation between the multiparticle or
the transverse energy distribution associated to a rare event , and
the corresponding minimum bias distribution P, , or works for nucleus-nucleus collisions as well as
for hadron-hadron collisions. This suggests that asymptotically, all hadronic
processes are similar.Comment: 9 pages, 4 Postscript figure
Solar models and solar neutrino oscillations
We provide a summary of the current knowledge, theoretical and experimental,
of solar neutrino fluxes and of the masses and mixing angles that characterize
solar neutrino oscillations. We also summarize the principal reasons for doing
new solar neutrino experiments and what we think may be learned from the future
measurements.Comment: Submitted to the Neutrino Focus Issue of New Journal of Physics at
http://www.njp.or
WHOI Hawaii Ocean Timeseries Station (WHOTS): WHOTS-11 2014 mooring Turnaround Cruise Report
The Woods Hole Oceanographic Institution (WHOI) Hawaii Ocean Timeseries Site (WHOTS),
100 km north of Oahu, Hawaii, is intended to provide long-term, high-quality air-sea fluxes as a
part of the NOAA Climate Observation Program. The WHOTS mooring also serves as a
coordinated part of the Hawaii Ocean Timeseries (HOT) program, contributing to the goals of
observing heat, fresh water and chemical fluxes at a site representative of the oligotrophic North
Pacific Ocean. The approach is to maintain a surface mooring outfitted for meteorological and
oceanographic measurements at a site near 22.75°N, 158°W by successive mooring turnarounds.
These observations will be used to investigate air–sea interaction processes related to climate
variability.
This report documents recovery of the tenth WHOTS mooring (WHOTS-10) and
deployment of the eleventh mooring (WHOTS-11). Both moorings used Surlyn foam buoys as
the surface element and were outfitted with two Air–Sea Interaction Meteorology (ASIMET)
systems. Each ASIMET system measures, records, and transmits via Argos satellite the surface
meteorological variables necessary to compute air–sea fluxes of heat, moisture and momentum.
The upper 155 m of the moorings were outfitted with oceanographic sensors for the
measurement of temperature, conductivity and velocity in a cooperative effort with R. Lukas of
the University of Hawaii. A pCO2 system and ancillary sensors were installed on the buoys in
cooperation with Chris Sabine at the Pacific Marine Environmental Laboratory. A set of
radiometers were installed in cooperation with Sam Laney at WHOI.
The WHOTS mooring turnaround was done on the NOAA ship Hi’ialakai by the Upper
Ocean Processes Group of the Woods Hole Oceanographic Institution. The cruise took place
between 15 and 23 July 2014. Operations began with deployment of the WHOTS-11 mooring on
16 July. This was followed by meteorological intercomparisons and CTDs. Recovery of the
WHOTS-10 mooring took place on 20 July. This report describes these cruise operations, as well
as some of the in-port operations and pre-cruise buoy preparations.Funding was provided by the National Oceanic and Atmospheric Administration under Grant No.
NA140AR4320158 and the Cooperative Institute for the North Atlantic Region (CINAR
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