7,301 research outputs found
Performances of linseed oil-free bakelite RPC prototypes with cosmic ray muons
A comparative study has been performed on Resistive Plate Chambers (RPC) made
of two different grades of bakelite paper laminates, produced and commercially
available in India. The chambers, operated in the streamer mode using argon,
tetrafluroethane and isobutane in 34:59:7 mixing ratio, are tested for the
efficiency and the stability with cosmic rays. A particular grade of bakelite
(P-120, NEMA LI-1989 Grade XXX), used for high voltage insulation in humid
conditions, was found to give satisfactory performance with stable efficiency
of > 96% continuously for more than 130 days. A thin coating of silicone fluid
on the inner surfaces of the bakelite RPC is found to be necessary for
operation of the detector.Comment: 6 figures, Presented in IX International Workshop on Resistive Plate
Chamber and related Detectors-2007, TIFR, Mumbai, India, February 13-16, 200
Illuminating hadron structure by scattering light on light
The results of an Amplitude Analysis of the world data on integrated and
differential cross-sections on are presented, following
the publication of the Belle charged pion results.Comment: 5 pages, 7 figures. To appear in the Proceedings of the International
Workshop on collisions from to , Frascati, April 2008.
This version rewords the reference to the work of Achasov and Shestakov, with
apologies to them for any misunderstandin
Strangeness production in jets from p+p \sqrt{s} = 200 GeV collisions
Measurements of strangeness production in jets help illuminate the QCD
mechanisms in fragmentation. Furthermore, they provide a crucial baseline for
heavy-ion studies where modifications in jet chemistry have recently been
predicted. We present new results on strange particle production in jets from
p+p \sqrt{s} = 200 GeV collisions measured by the STAR experiment. The momentum
distributions of the \Lambda, \bar{\Lambda} and K0Short particles are obtained
using various jet finding algorithms, and then compared to various models.
Strange particle ratios in jets are obtained and compared to values obtained
from the inclusive spectra. Finally, we show jets tagged with leading strange
baryons and mesons, in order to investigate whether gluon or quark jets can be
isolated in this way.Comment: 5 pages, 4 figures, Winter Workshop on Nuclear Dynamics 2010, Jamaic
Study of isobar electroproduction at VEPP-2M collider
Results from the Spherical Nonmagnetic Detector (SND) on
isobar electroproduction in the collisions of beam electrons (positrons) and
residual gas nuclei in the VEPP-2M collider are presented. On the
basis of the obtained data the expected counting rate of this process in future
high luminosity colliders (~-, -- and -factories)
was estimated.Comment: 7 pages LATEX and 3 figure
A triple GEM gamma camera for medical application
Abstract A Gamma Camera for medical applications 10 × 10 cm 2 has been built using a triple GEM chamber prototype. The photon converters placed in front of the three GEM foils, has been realized with different technologies. The chamber, High Voltage supplied with a new active divider made in Frascati, is readout through 64 pads, 1 mm 2 wide, organized in a row of 8 cm long, with LHCb ASDQ chip. This Gamma Camera can be used both for X-ray movie and PET-SPECT imaging; this chamber prototype is placed in a scanner system, creating images of 8 × 8 cm 2 . Several measurements have been performed using phantom and radioactive sources of Tc 99 m ( 140 keV ) and Na 22 ( 511 keV ) . Results on spatial resolution and image reconstruction are presented
Prospects for Pentaquark Searches in Annihilations and Collisions
Recent strong experimental evidence of a narrow exotic S = +1 baryon
resonance, , suggests the existence of other exotic baryons. We
discuss the prospects of confirming earlier experimental evidence of
and the observation of additional hypothetical exotic baryons in
annihilations and collisions at LEP and B Factories
LEMMA approach for the production of low-emittance muon beams
This work introduces an experimental test of the new proposal for a low–emittance muon accelerator (LEMMA). A low–emittance muon beam is obtained from the e+e− → μ+μ− annihilation process at the threshold energy of 45 GeV eliminating the need for a dedicated muon cooling system. A series of two testbeam campaigns were carried out at CERN to validate this concept. The experimental setup is presented together with first preliminary results from the obtained data
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Measurement of Azimuthal Anisotropy of Muons from Charm and Bottom Hadrons in pp Collisions at sqrt[s]=13 TeV with the ATLAS Detector.
The elliptic flow of muons from the decay of charm and bottom hadrons is measured in pp collisions at sqrt[s]=13 TeV using a data sample with an integrated luminosity of 150 pb^{-1} recorded by the ATLAS detector at the LHC. The muons from heavy-flavor decay are separated from light-hadron decay muons using momentum imbalance between the tracking and muon spectrometers. The heavy-flavor decay muons are further separated into those from charm decay and those from bottom decay using the distance-of-closest-approach to the collision vertex. The measurement is performed for muons in the transverse momentum range 4-7 GeV and pseudorapidity range |η|<2.4. A significant nonzero elliptic anisotropy coefficient v_{2} is observed for muons from charm decays, while the v_{2} value for muons from bottom decays is consistent with zero within uncertainties
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