35 research outputs found
Coronal Temperature Diagnostic Capability of the Hinode/X-Ray Telescope Based on Self-Consistent Calibration
The X-Ray Telescope (XRT) onboard the Hinode satellite is an X-ray imager
that observes the solar corona with unprecedentedly high angular resolution
(consistent with its 1" pixel size). XRT has nine X-ray analysis filters with
different temperature responses. One of the most significant scientific
features of this telescope is its capability of diagnosing coronal temperatures
from less than 1 MK to more than 10 MK, which has never been accomplished
before. To make full use of this capability, accurate calibration of the
coronal temperature response of XRT is indispensable and is presented in this
article. The effect of on-orbit contamination is also taken into account in the
calibration. On the basis of our calibration results, we review the
coronal-temperature-diagnostic capability of XRT
Scaling violations: Connections between elastic and inelastic hadron scattering in a geometrical approach
Starting from a short range expansion of the inelastic overlap function,
capable of describing quite well the elastic pp and scattering data,
we obtain extensions to the inelastic channel, through unitarity and an impact
parameter approach. Based on geometrical arguments we infer some
characteristics of the elementary hadronic process and this allows an excellent
description of the inclusive multiplicity distributions in and
collisions. With this approach we quantitatively correlate the violations of
both geometrical and KNO scaling in an analytical way. The physical picture
from both channels is that the geometrical evolution of the hadronic
constituents is principally reponsible for the energy dependence of the
physical quantities rather than the dynamical (elementary) interaction itself.Comment: 16 pages, aps-revtex, 11 figure
Search for Colour Singlet and Colour Reconnection Effects in Hadronic Z Decays at LEP
A search is performed in symmetric 3-jet hadronic Z decay events for evidence
of colour singlet production or colour reconnection effects. Asymmetries in the
angular separation of particles are found to be sensitive indicators of such
effects. Upper limits on the level of colour singlet production and colour
reconnection effects are established for a variety of models
Measurement of Bose-Einstein Correlations in e+e- -> W+W- at root(s)=189GeV
We investigate Bose-Einstein correlations (BEC) in W-pair production at
root(s)=189GeV using the L3 detector at LEP. We observe BEC between particles
from a single W decay in good agreement with those from a light-quark Z decay
sample. We investigate their possible existence between particles coming from
different W's. No evidence for such inter-W BEC is found
Longitudinal scaling property of the charge balance function in Au + Au collisions at 200 GeV
We present measurements of the charge balance function, from the charged
particles, for diverse pseudorapidity and transverse momentum ranges in Au + Au
collisions at 200 GeV using the STAR detector at RHIC. We observe that the
balance function is boost-invariant within the pseudorapidity coverage [-1.3,
1.3]. The balance function properly scaled by the width of the observed
pseudorapidity window does not depend on the position or size of the
pseudorapidity window. This scaling property also holds for particles in
different transverse momentum ranges. In addition, we find that the width of
the balance function decreases monotonically with increasing transverse
momentum for all centrality classes.Comment: 6 pages, 3 figure
Measurement of the Topological Branching Fractions of the tau lepton at LEP
Using data collected with the L3 detector at LEP from 1992 to 1995 on the Z
peak, we determine the branching fractions of the tau lepton into one, three
and five charged particles to be:
B(tau->(1-prong)) = 85.274 +- 0.105 +- 0.073 %,
B(tau->(3-prong)) = 14.556 +- 0.105 +- 0.076 %,
B(tau->(5-prong)) = 0.170 +- 0.022 +- 0.026 %.
The first uncertainties are statistical and the second systematic. The
accuracy of these measurements alone is similar to that of the current world
average
Studies of Hadronic Event Structure in e+e- Annihilation from 30 GeV to 209 GeV with the L3 Detector
In this Report, QCD results obtained from a study of hadronic event structure
in high energy e^+e^- interactions with the L3 detector are presented. The
operation of the LEP collider at many different collision energies from 91 GeV
to 209 GeV offers a unique opportunity to test QCD by measuring the energy
dependence of different observables. The main results concern the measurement
of the strong coupling constant, \alpha_s, from hadronic event shapes and the
study of effects of soft gluon coherence through charged particle multiplicity
and momentum distributions.Comment: To appear in Physics Report
Galaxy Clusters Associated with Short GRBs. II. Predictions for the Rate of Short GRBs in Field and Cluster Early-Type Galaxies
We determine the relative rates of short GRBs in cluster and field early-type
galaxies as a function of the age probability distribution of their
progenitors, P(\tau) \propto \tau^n. This analysis takes advantage of the
difference in the growth of stellar mass in clusters and in the field, which
arises from the combined effects of the galaxy stellar mass function, the
early-type fraction, and the dependence of star formation history on mass and
environment. This approach complements the use of the early- to late-type host
galaxy ratio, with the added benefit that the star formation histories of
early-type galaxies are simpler than those of late-type galaxies, and any
systematic differences between progenitors in early- and late-type galaxies are
removed. We find that the ratio varies from R(cluster)/R(field) ~ 0.5 for n =
-2 to ~ 3 for n = 2. Current observations indicate a ratio of about 2,
corresponding to n ~ 0 - 1. This is similar to the value inferred from the
ratio of short GRBs in early- and late-type hosts, but it differs from the
value of n ~ -1 for NS binaries in the Milky Way. We stress that this general
approach can be easily modified with improved knowledge of the effects of
environment and mass on the build-up of stellar mass, as well as the effect of
globular clusters on the short GRB rate. It can also be used to assess the age
distribution of Type Ia supernova progenitors.Comment: ApJ accepted versio
Palaeomagnetism of the AND-2A Core, ANDRILL Southern McMurdo Sound Project, Antarctica
We conducted initial palaeomagnetic studies on cores from site AND-2A (77°45.488’S,
165°16.605’E, ~383.57 metres water depth). A total of 813 samples were collected that span from the
top of the section down to the base at 1138.54 metres below sea floor (mbsf). Samples were collected
every one or two metres down the core, with paired (pilot) samples being collected about every ten to
twenty metres to allow us to assess the demagnetisation behaviour of the samples using either alternating
field (AF) or thermal demagnetisation. With the exception of only a few intervals, AF demagnetisation
was observed to resolve a characteristic remanent magnetisation (ChRM) as well or better than thermal
demagnetisation. Thermal demagnetisation was particularly ineffective in many intervals owing to thermal
alteration that was common above 500°C and was evident in some samples even at low temperatures.
Above Lithostratigraphic Unit (LSU) 8 (436.18 mbsf), where lithologies are generally more coarse grained
than lower in the section, resolving a ChRM is difficult and recent overprints or a drilling overprint are a
concern. Within LSU 8 and below, most samples have a ChRM that can be resolved. The ChRM is most
likely an original depositional magnetisation throughout most of this lower section, although orthogonal
demagnetisation diagrams contain evidence that normal polarity overprinting affects some intervals. Based on
40Ar/39Ar dates and diatom datums, the magnetozones identified from the base of the hole up to ~266mbsf
are consistent with spanning from either Chron C6n (18.748-19.772 Ma) or C6An.1n (20.040-20.213 Ma)
up through Chron C5Br (15.160-15.974 Ma). Above this, intervals of constant polarity are isolated within
longer stratigraphic intervals of uncertain polarity, making their correlation with the geomagnetic polarity
timescale (GPTS) speculative and highly dependent on ages obtained from other dating methods. One
exception is a reversed-to-normal polarity transition that occurs at ~31 mbsf and is interpreted to most
likely be the Brunhes/Matuyama boundary. The spacing of polarity reversals below 266 mbsf and their
correlation with the GPTS indicates that this part of the stratigraphic section was deposited between 15
to 20 Ma at a mean sedimentation rate of about 18 centimetres (cm)/ thousand year (k.y.).Published193-2102.2. Laboratorio di paleomagnetismoN/A or not JCRreserve