62 research outputs found
Observation of neutrino interactions in the OPERA detector
OPERA is a long baseline neutrino oscillation experiment designed to observe
oscillations by looking at the appearance of
's in an almost pure beam. The beam is produced at CERN
and sent towards the Gran Sasso INFN laboratories where the experiment is
running. OPERA started its data taking in October 2007, when the first 38
neutrino interactions where successfully located and reconstructed. This paper
reviews the status of the experiment discussing its physics potential and
performances for neutrino oscillation studies.Comment: 7 pages, 6 figure
Process and Data Flow Control in KLOE
Abstract The core of the KLOE distributed event building system is a switched network. The online processes are distributed over a large set of processors in this network. All processes have to change coherently their state of activity as a consequence of local or remote commands. A fast and reliable message system based on the SNMP protocol has been developed. A command server has been implemented as a non privileged daemon able to respond to "set" and "get" queries on private SNMP variables. This process is able to convert remote set operations into local commands and to map automatically an SNMP subtree on a user-defined set of process variables. Process activity can be continuously monitored by remotely accessing their variables by means of the command server. Only the command server is involved in these operations, without disturbing the process flow. Subevents coming from subdetectors are sent to different nodes of a computing farm for the last stage of event building. Based on features of the SNMP protocol and of the KLOE message system, the Data Flow Control System (DFC) is able to rapidly redirect network traffic, keeping in account the dynamics of the whole DAQ system in order to assure coherent subevent addressing in an asynchronous "push" architecture, without introducing dead time. The KLOE DFC is currently working in the KLOE DAQ system. Its main characteristics and performance are discussed
First T2K measurement of transverse kinematic imbalance in the muon-neutrino charged-current single pi+ production channel containing at least one proton
This paper reports the first T2K measurement of the transverse kinematic imbalance in the single-pi+ production channel of neutrino interactions. We measure the differential cross sections in the muon-neutrino charged-current interaction on hydrocarbon with a single pi+ and at least one proton in the final state, at the ND280 off axis near detector of the T2K experiment. The extracted cross sections are compared to the predictions from different neutrino-nucleus interaction event generators. Overall, the results show a preference for models that have a more realistic treatment of nuclear medium effects including the initial nuclear state and final-state interactions
Improved constraints on neutrino mixing from the T2K experiment with 3.13 x10^21 protons on target
The T2K experiment reports updated measurements of neutrino and antineutrino oscillations using both appearance and disappearance channels. This result comes from an exposure of 14.9 (16.4) × 10^20 protons on target in neutrino (antineutrino) mode. Significant improvements have been made to the neutrino interaction model and far detector reconstruction. An extensive set of simulated data studies have also been performed to quantify the effect interaction model uncertainties have on the T2K oscillation parameter sensitivity. T2K performs multiple oscillation analyses that present both frequentist and Bayesian intervals for the Pontecorvo-Maki-Nakagawa-Sakata parameters. For fits including a constraint on sin^2θ13 from reactor data and assuming normal mass ordering T2K measures sin^2θ_23 = 0.53+0.03−0.04 and Δm^2_32 = (2.45+-0.07) × 10^−3 eV^2 c^−4. The Bayesian analyses show a weak preference for normal mass ordering 89 % posterior probability) and the upper sin^2 θ_23 octant (80% posterior probability), with a uniform prior probability assumed in both cases. The T2K data exclude CP conservation in neutrino oscillations at the 2σ level
Nuclear Emulsion Film Detectors for Proton Radiography: Design and Test of the First Prototype
Proton therapy is nowadays becoming a wide spread clinical practice in cancer
therapy and sophisticated treatment planning systems are routinely used to
exploit at best the ballistic properties of charged particles. The information
on the quality of the beams and the range of the protons is a key issue for the
optimization of the treatment. For this purpose, proton radiography can be used
in proton therapy to obtain direct information on the range of the protons, on
the average density of the tissues for treatment planning optimization and to
perform imaging with negligible dose to the patient. We propose an innovative
method based on nuclear emulsion film detectors for proton radiography, a
technique in which images are obtained by measuring the position and the
residual range of protons passing through the patient's body. Nuclear emulsion
films interleaved with tissue equivalent absorbers can be fruitfully used to
reconstruct proton tracks with very high precision. The first prototype of a
nuclear emulsion based detector has been conceived, constructed and tested with
a therapeutic proton beam at PSI. The scanning of the emulsions has been
performed at LHEP in Bern, where a fully automated microscopic scanning
technology has been developed for the OPERA experiment on neutrino
oscillations. After track reconstruction, the first promising experimental
results have been obtained by imaging a simple phantom made of PMMA with a step
of 1 cm. A second phantom with five 5 x 5 mm^2 section aluminum rods located at
different distances and embedded in a PMMA structure has been also imaged.
Further investigations are in progress to improve the resolution and to image
more sophisticated phantoms.Comment: Presented at the 11th ICATPP Conference on Astroparticle, Particle,
Space Physics, Detectors and Medical Physics Applications, Como (Italy),
October 200
Measurements of π± , K± , p and p¯ 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 π±, K±, p and p¯ produced in
inelastic p+p interactions at incident projectile momenta of 20, 31, 40, 80 and 158 GeV/c
(√s = 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
A Ramsey apparatus for proton spins in flowing water
We present an apparatus that applies Ramsey's method of separated oscillatory
fields to proton spins in water molecules. The setup consists of a water
circuit, a spin polarizer, a magnetically shielded interaction region with
various radio frequency elements, and a nuclear magnetic resonance system to
measure the spin polarization. We show that this apparatus can be used for Rabi
resonance measurements and to investigate magnetic and pseudomagnetic field
effects in Ramsey-type precision measurements with a sensitivity below 100 pT
SMAUG v1.0 – a user-friendly muon simulator for the imaging of geological objects in 3-D
Knowledge about muon tomography has spread in recent years in the geoscientific community and several collaborations between geologists and physicists have been founded. As the data analysis is still mostly done by particle physicists, much of the know-how is concentrated in particle physics and specialised geophysics institutes. SMAUG (Sim- ulation for Muons and their Applications UnderGround), a toolbox consisting of several modules that cover the various aspects of data analysis in a muon tomographic experiment, aims at providing access to a structured data analysis frame- work. The goal of this contribution is to make muon tomog- raphy more accessible to a broader geoscientific audience. In this study, we show how a comprehensive geophysical model can be built from basic physics equations. The emerging un- certainties are dealt with by a probabilistic formulation of the inverse problem, which is finally solved by a Monte Carlo Markov chain algorithm. Finally, we benchmark the SMAUG results against those of a recent study, which, however, have been established with an approach that is not easily accessi- ble to the geoscientific community. We show that they reach identical results with the same level of accuracy and preci- sion
New Limit on Axion-Dark-Matter using Cold Neutrons
We report on a search for axion-like dark matter using a Ramsey-type
apparatus for cold neutrons. A hypothetical axion-gluon-coupling would manifest
in a neutron electric dipole moment signal oscillating in time. Twenty-four
hours of data have been analyzed in a frequency range from 23 Hz to 1 kHz,
and no significant oscillating signal has been found. The usage of present
axion and dark-matter models allowed excluding the coupling of axions to gluons
in the mass range from to eV with a
best sensitivity of GeV
(95% C.L.)
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