620 research outputs found
The T2K experiment and its time projection chambers
The Tokai to Kamioka (T2K) experiment [1] is a long baseline neutrino oscillation experiment located in Japan and its goal is to gain a more complete understanding of the neutrino oscillation parameters. A highly pure muon neutrino beam is directed from the accelerator center JPARC towards the Super-Kamiokande (SK) detector, which is 295 km away. A key element of the design of the T2K facility is the use of an off-axis technique. The main physics goals of T2K are to measure the mixing angle θ13 in a νe appearance experiment and improve the measurement of the atmospheric parameters ∆m 2 23 and θ23 using the νµ disappearance channel. The near detector (ND280), located 280 m away from the target, will measure the neutrino beam properties and the neutrino interaction cross section and kinematics before the oscillation, in order to predict the relevant neutrino interactions at SK. It consistes of a magnet, a Pi-Zero Detector (optimized for measuring the rate of neutral current π0 production), an electromagnetic calorimeter (whose main purpose is to measure the photons produced in ND280), a Side Muon Range Detector (to measure the range of muons that exit the sides of ND280) and a tracker (optimized for measuring the momenta of charged particles). The tracking device consists of a sandwich of three time projection chambers (TPCs) and two fine grained detectors (FGDs) which provide the target material. An overview of the TPC calibration methods and some results from the tests done at CERN to study the performance of the TPC readout modules are presented
Multiplicity and transverse momentum fluctuations in inelastic proton-proton interactions at the CERN Super Proton Synchrotron
Measurements of multiplicity and transverse momentum fluctuations of charged
particles were performed in inelastic p+p interactions at 20, 31, 40, 80 and
158 GeV/c beam momentum. Results for the scaled variance of the multiplicity
distribution and for three strongly intensive measures of multiplicity and
transverse momentum fluctuations \$\Delta[P_{T},N]\$, \$\Sigma[P_{T},N]\$ and
\$\Phi_{p_T}\$ are presented. For the first time the results on fluctuations
are fully corrected for experimental biases. The results on multiplicity and
transverse momentum fluctuations significantly deviate from expectations for
the independent particle production. They also depend on charges of selected
hadrons. The string-resonance Monte Carlo models EPOS and UrQMD do not describe
the data. The scaled variance of multiplicity fluctuations is significantly
higher in inelastic p+p interactions than in central Pb+Pb collisions measured
by NA49 at the same energy per nucleon. This is in qualitative disagreement
with the predictions of the Wounded Nucleon Model. Within the statistical
framework the enhanced multiplicity fluctuations in inelastic p+p interactions
can be interpreted as due to event-by-event fluctuations of the fireball energy
and/or volume.Comment: 18 pages, 12 figure
Measurements of , K, p and spectra in proton-proton interactions at 20, 31, 40, 80 and 158 GeV/c with the NA61/SHINE spectrometer at the CERN SPS
Measurements of inclusive spectra and mean multiplicities of ,
K, p and produced in inelastic p+p interactions at
incident projectile momenta of 20, 31, 40, 80 and 158 GeV/c ( 6.3,
7.7, 8.8, 12.3 and 17.3 GeV, respectively) were performed at the CERN Super
Proton Synchrotron using the large acceptance NA61/SHINE hadron spectrometer.
Spectra are presented as function of rapidity and transverse momentum and are
compared to predictions of current models. The measurements serve as the
baseline in the NA61/SHINE study of the properties of the onset of
deconfinement and search for the critical point of strongly interacting matter
Pion emission from the T2K replica target: method, results and application
The T2K long-baseline neutrino oscillation experiment in Japan needs precise
predictions of the initial neutrino flux. The highest precision can be reached
based on detailed measurements of hadron emission from the same target as used
by T2K exposed to a proton beam of the same kinetic energy of 30 GeV. The
corresponding data were recorded in 2007-2010 by the NA61/SHINE experiment at
the CERN SPS using a replica of the T2K graphite target. In this paper details
of the experiment, data taking, data analysis method and results from the 2007
pilot run are presented. Furthermore, the application of the NA61/SHINE
measurements to the predictions of the T2K initial neutrino flux is described
and discussed.Comment: updated version as published by NIM
Measurements of , , , and proton production in proton-carbon interactions at 31 GeV/ with the NA61/SHINE spectrometer at the CERN SPS
Measurements of hadron production in p+C interactions at 31 GeV/c are
performed using the NA61/ SHINE spectrometer at the CERN SPS. The analysis is
based on the full set of data collected in 2009 using a graphite target with a
thickness of 4% of a nuclear interaction length. Inelastic and production cross
sections as well as spectra of , , p, and are
measured with high precision. These measurements are essential for improved
calculations of the initial neutrino fluxes in the T2K long-baseline neutrino
oscillation experiment in Japan. A comparison of the NA61/SHINE measurements
with predictions of several hadroproduction models is presented.Comment: v1 corresponds to the preprint CERN-PH-EP-2015-278; v2 matches the
final published versio
NA61/SHINE facility at the CERN SPS: beams and detector system
NA61/SHINE (SPS Heavy Ion and Neutrino Experiment) is a multi-purpose
experimental facility to study hadron production in hadron-proton,
hadron-nucleus and nucleus-nucleus collisions at the CERN Super Proton
Synchrotron. It recorded the first physics data with hadron beams in 2009 and
with ion beams (secondary 7Be beams) in 2011.
NA61/SHINE has greatly profited from the long development of the CERN proton
and ion sources and the accelerator chain as well as the H2 beamline of the
CERN North Area. The latter has recently been modified to also serve as a
fragment separator as needed to produce the Be beams for NA61/SHINE. Numerous
components of the NA61/SHINE set-up were inherited from its predecessors, in
particular, the last one, the NA49 experiment. Important new detectors and
upgrades of the legacy equipment were introduced by the NA61/SHINE
Collaboration.
This paper describes the state of the NA61/SHINE facility - the beams and the
detector system - before the CERN Long Shutdown I, which started in March 2013
Measurement of negatively charged pion spectra in inelastic p+p interactions at = 20, 31, 40, 80 and 158 GeV/c
We present experimental results on inclusive spectra and mean multiplicities
of negatively charged pions produced in inelastic p+p interactions at incident
projectile momenta of 20, 31, 40, 80 and 158 GeV/c ( 6.3, 7.7,
8.8, 12.3 and 17.3 GeV, respectively). The measurements were performed using
the large acceptance NA61/SHINE hadron spectrometer at the CERN Super Proton
Synchrotron.
Two-dimensional spectra are determined in terms of rapidity and transverse
momentum. Their properties such as the width of rapidity distributions and the
inverse slope parameter of transverse mass spectra are extracted and their
collision energy dependences are presented. The results on inelastic p+p
interactions are compared with the corresponding data on central Pb+Pb
collisions measured by the NA49 experiment at the CERN SPS.
The results presented in this paper are part of the NA61/SHINE ion program
devoted to the study of the properties of the onset of deconfinement and search
for the critical point of strongly interacting matter. They are required for
interpretation of results on nucleus-nucleus and proton-nucleus collisions.Comment: Numerical results available at: https://edms.cern.ch/document/1314605
Updates in v3: Updated version, as accepted for publicatio
The LBNO long-baseline oscillation sensitivities with two conventional neutrino beams at different baselines
The proposed Long Baseline Neutrino Observatory (LBNO) initially consists of
kton liquid double phase TPC complemented by a magnetised iron
calorimeter, to be installed at the Pyh\"asalmi mine, at a distance of 2300 km
from CERN. The conventional neutrino beam is produced by 400 GeV protons
accelerated at the SPS accelerator delivering 700 kW of power. The long
baseline provides a unique opportunity to study neutrino flavour oscillations
over their 1st and 2nd oscillation maxima exploring the behaviour, and
distinguishing effects arising from and matter. In this paper we
show how this comprehensive physics case can be further enhanced and
complemented if a neutrino beam produced at the Protvino IHEP accelerator
complex, at a distance of 1160 km, and with modest power of 450 kW is aimed
towards the same far detectors. We show that the coupling of two independent
sub-MW conventional neutrino and antineutrino beams at different baselines from
CERN and Protvino will allow to measure CP violation in the leptonic sector at
a confidence level of at least for 50\% of the true values of
with a 20 kton detector. With a far detector of 70 kton, the
combination allows a sensitivity for 75\% of the true values of
after 10 years of running. Running two independent neutrino
beams, each at a power below 1 MW, is more within today's state of the art than
the long-term operation of a new single high-energy multi-MW facility, which
has several technical challenges and will likely require a learning curve.Comment: 21 pages, 12 figure
Measurement of Production Properties of Positively Charged Kaons in Proton-Carbon Interactions at 31 GeV/c
Spectra of positively charged kaons in p+C interactions at 31 GeV/c were
measured with the NA61/SHINE spectrometer at the CERN SPS. The analysis is
based on the full set of data collected in 2007 with a graphite target with a
thickness of 4% of a nuclear interaction length. Interaction cross sections and
charged pion spectra were already measured using the same set of data. These
new measurements in combination with the published ones are required to improve
predictions of the neutrino flux for the T2K long baseline neutrino oscillation
experiment in Japan. In particular, the knowledge of kaon production is crucial
for precisely predicting the intrinsic electron neutrino component and the high
energy tail of the T2K beam. The results are presented as a function of
laboratory momentum in 2 intervals of the laboratory polar angle covering the
range from 20 up to 240 mrad. The kaon spectra are compared with predictions of
several hadron production models. Using the published pion results and the new
kaon data, the K+/\pi+ ratios are computed.Comment: 10 pages, 11 figure
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