3,265 research outputs found
Measurement of the Ï„ lepton electric dipole moment at BaBar
The search for a CP violation signature arising from an electric dipole moment of the τ lepton in the e+e− → τ+τ−
reaction is currently in progress using 470 fb−1 of data collected with the BaBar detector at the PEP II collider from 1999 to 2008. In this paper the EDM search analysis method will be illustrated
Measurement of the Ï„ lepton electric dipole moment at BaBar
The search for a CP violation signature arising from an electric dipole moment of the τ lepton in the e+e− → τ+τ−
reaction is currently in progress using 470 fb−1 of data collected with the BaBar detector at the PEP II collider
from 1999 to 2008. In this paper the EDM search method in development will be illustrated and the required algorithms tested on Monte Carlo samples that do not take into account the detector and background effects are shown
Spectrometer for laser-plasma accelerated electrons at PlasmonX at the Frascati National Laboratory
This paper describes the characteristics of the magnetic spectrometer realized for the laser-plasma acceleration experiment PlasmonX at the Frascati National Laboratory. The laser-plasma interaction produces bunches of about 1010 e− with energies spreading over three orders of magnitude from a few MeV to the GeV region
Scintillating properties of frozen new liquid scintillators
The light emission from scintillators which are liquid at room temperature was studied in the interval between ~C and ~C, where the phase transition from liquid to solid takes place. The light yield measured at ~C is about twice as much as that observed at ~C. By cooling the scintillator from ~C to ~C and then heating it from ~C to ~C, the light yield varies in steps at well defined temperatures, which are different for the cooling and heating processes. These hysteresis phenomena appear to be related to the solvent rather than to the dopant. The decay time of scintillation light was measured at ~C and ~C. Whilst at room temperature most of the light is emitted with a decay time of 6--8 ns, at ~C a slower component, with a decay time of 25--35 ns, becomes important
Performance of the LHCb muon system with cosmic rays
The LHCb Muon system performance is presented using cosmic ray events
collected in 2009. These events allowed to test and optimize the detector
configuration before the LHC start. The space and time alignment and the
measurement of chamber efficiency, time resolution and cluster size are
described in detail. The results are in agreement with the expected detector
performance.Comment: Submitted to JINST and accepte
Performance of the Muon Identification at LHCb
The performance of the muon identification in LHCb is extracted from data
using muons and hadrons produced in J/\psi->\mu\mu, \Lambda->p\pi and
D^{\star}->\pi D0(K\pi) decays. The muon identification procedure is based on
the pattern of hits in the muon chambers. A momentum dependent binary
requirement is used to reduce the probability of hadrons to be misidentified as
muons to the level of 1%, keeping the muon efficiency in the range of 95-98%.
As further refinement, a likelihood is built for the muon and non-muon
hypotheses. Adding a requirement on this likelihood that provides a total muon
efficiency at the level of 93%, the hadron misidentification rates are below
0.6%.Comment: 17 pages, 10 figure
Multi-GeV Electron Spectrometer
The advance in laser plasma acceleration techniques pushes the regime of the
resulting accelerated particles to higher energies and intensities. In
particular the upcoming experiments with the FLAME laser at LNF will enter the
GeV regime with almost 1pC of electrons. From the current status of
understanding of the acceleration mechanism, relatively large angular and
energy spreads are expected. There is therefore the need to develop a device
capable to measure the energy of electrons over three orders of magnitude (few
MeV to few GeV) under still unknown angular divergences. Within the PlasmonX
experiment at LNF a spectrometer is being constructed to perform these
measurements. It is made of an electro-magnet and a screen made of
scintillating fibers for the measurement of the trajectories of the particles.
The large range of operation, the huge number of particles and the need to
focus the divergence present unprecedented challenges in the design and
construction of such a device. We will present the design considerations for
this spectrometer and the first results from a prototype.Comment: 7 pages, 6 figures, submitted to NIM
Beam test, simulation, and performance evaluation of PbF and PWO-UF crystals with SiPM readout for a semi-homogeneous calorimeter prototype with longitudinal segmentation
Crilin (Crystal Calorimeter with Longitudinal Information) is a
semi-homogeneous, longitudinally segmented electromagnetic calorimeter based on
high-, ultra-fast crystals with UV-extended SiPM readout. The Crilin design
has been proposed as a candidate solution for both a future Muon Collider
barrel ECAL and for the Small Angle Calorimeter of the HIKE experiment. As a
part of the Crilin development program, we have carried out beam tests of small
(~mm) lead fluoride (PbF) and ultra-fast lead
tungstate (PbWO, PWO) crystals with 120~GeV electrons at the CERN SPS to
study the light yield, timing response, and systematics of light collection
with a proposed readout scheme. For a single crystal of PbF, corresponding
to a single Crilin cell, a time resolution of better than 25~ps is obtained for
3 GeV of deposited energy. For a single cell of \pwo, a time resolution of
better than 45~ps is obtained for the same range of deposited energy. This
timing performance fully satisfies the design requirements for the Muon
Collider and HIKE experiments. Further optimizations of the readout scheme and
crystal surface preparation are expected to bring further improvements
Performance of the LHCb muon system
The performance of the LHCb Muon system and its stability across the full
2010 data taking with LHC running at ps = 7 TeV energy is studied. The
optimization of the detector setting and the time calibration performed with
the first collisions delivered by LHC is described. Particle rates, measured
for the wide range of luminosities and beam operation conditions experienced
during the run, are compared with the values expected from simulation. The
space and time alignment of the detectors, chamber efficiency, time resolution
and cluster size are evaluated. The detector performance is found to be as
expected from specifications or better. Notably the overall efficiency is well
above the design requirementsComment: JINST_015P_1112 201
Measurement of the front-end dead-time of the LHCb muon detector and evaluation of its contribution to the muon detection inefficiency
A method is described which allows to deduce the dead-time of the front-end
electronics of the LHCb muon detector from a series of measurements performed
at different luminosities at a bunch-crossing rate of 20 MHz. The measured
values of the dead-time range from 70 ns to 100 ns. These results allow to
estimate the performance of the muon detector at the future bunch-crossing rate
of 40 MHz and at higher luminosity
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