Search results for "Instrumentation"
showing 10 items of 4914 documents
The DIRC detectors at the PANDA experiment
2015
PANDA is an experiment at the new FAIR facility at GSI and will, among other physics goals,\ud perform charmonium spectroscopy and search for gluonic excitations using high luminosity antiproton beams up to 15 GeV/c. A high performance particle identification system applying DIRC\ud detectors will allow pion/kaon separation up to 4 GeV/c. A Barrel DIRC with fused silica radiator bars or plates will surround the target at a radial distance of 48 cm and will cover a polar\ud angle range of 22 to 140 degrees; a novel Endcap Disk DIRC built of a segmented fused silica\ud disk of 210 cm diameter will be installed in the forward region to cover the polar angles from\ud 5 to 22 degrees. The design…
Determining the neutrino mass hierarchy and CP-violation in NO nu A with a second off-axis detector
2006
We consider a Super-NO nu A-like experimental configuration based on the use of two detectors in a long-baseline experiment as NO nu A. We take the far detector as in the present NO nu A proposal and add a second detector at a shorter baseline. The location of the second off-axis detector is chosen such that the ratio L/E is the same for both detectors, being L the baseline and E the neutrino energy. We consider liquid argon and water-Cerenkov techniques for the second off-axis detector and study, for different experimental setups, the detector mass required for the determination of the neutrino mass hierarchy, for different values of theta(13). We also study the capabilities of such an exp…
A small glass calorimeter
2008
A smallscale glass calorimeter has been designed and constructed to reduce around 90% of the volume of reagents required for thermochemical experiments performed in Dewar flasks and Styrofoam or polystyrene cups. The description and calibration of the calorimeter is shown and one example is given in order to illustrate the advantages of working with a transparent calorimeter.
Precision Measurement of the (7)Be Solar Neutrino Interaction Rate in Borexino
2011
A direct measurement of the 0.862 MeV 7Be solar neutrino interaction rate performed with the Borexino detector at the Laboratori Nazionali del Gran Sasso yields 46.0±1.5stat+1.6−1.5syst counts/day/(100 tons). Our result is the first direct measurement of a sub-MeV solar neutrino rate with an accuracy better than 5%. The hypothesis of no oscillation for 7Be solar neutrinos is rejected at 4.9σ C.L. Using the latest Standard Solar Model (SSM) flux predictions, the result leads directly to a precise determination of the survival probability for solar νe's in vacuum, and permits us to probe with unprecedented sensitivity the transition between the matter-enhanced and vacuum-dominated neutrino os…
Relic neutrino decoupling with oscillations revisited
2016
We study the decoupling process of neutrinos in the early universe in the presence of three-flavour oscillations. The evolution of the neutrino spectra is found by solving the corresponding momentum-dependent kinetic equations for the neutrino density matrix, including for the rst time the proper collision integrals for both diagonal and o -diagonal elements. This improved calculation modi es the evolution of the o -diagonal elements of the neutrino density matrix and changes the deviation from equilibrium of the frozen neutrino spectra. However, it does not vary the contribution of neutrinos to the cosmological energy density in the form of radiation, usually expressed in terms of the e ec…
Before and after: how has the SNO neutral current measurement changed things?
2002
We present Before and After global oscillation solutions, as well as predicted Before and After values and ranges for ten future solar neutrino observables (for BOREXINO, KamLAND, SNO, and a generic p-p neutrino detector). The 'Before' case includes all solar neutrino data (and some theoretical improvements) available prior to April 20, 2002 and the After case includes, in addition, the new SNO data on the CC, NC, and day-night asymmetry. We have performed global analyses using the full SNO day-night energy spectrum and, alternatively, using just the SNO NC and CC rates and the day-night asymmetry. The LMA solution is the only currently allowed MSW oscillation solution at similar to99% CL. …
Search for nonpointing photons in the diphoton and E-T(miss) final state in root s=7 TeV proton-proton collisions using the ATLAS detector
2013
A search has been performed for photons originating in the decay of a neutral long-lived particle, exploiting the capabilities of the ATLAS electromagnetic calorimeter to make precise measurements of the flight direction of photons, as well as the calorimeter's excellent time resolution. The search has been made in the diphoton plus missing transverse energy final state, using the full data sample of 4.8 fb(-1) of 7 TeV proton-proton collisions collected in 2011 with the ATLAS detector at the LHC. No excess is observed above the background expected from Standard Model processes. The results are used to set exclusion limits in the context of gauge mediated supersymmetry breaking models, with…
Searches for heavy long-lived sleptons and R-hadrons with the ATLAS detector in pp collisions at root s=7 TeV
2013
A search for long-lived particles is performed using a data sample of 4.7 fb-1 from proton-proton collisions at a centre-of-mass energy sqrt(s) = 7 TeV collected by the ATLAS detector at the LHC. No excess is observed above the estimated background and lower limits, at 95% confidence level, are set on the mass of the long-lived particles in different scenarios, based on their possible interactions in the inner detector, the calorimeters and the muon spectrometer. Long-lived staus in gauge-mediated SUSY-breaking models are excluded up to a mass of 300 GeV for tan beta = 5-20. Directly produced long-lived sleptons are excluded up to a mass of 278 GeV. R-hadrons, composites of gluino (stop, sb…
First measurement of Ξc0 production in pp collisions at √s = 7 TeV
2018
The production of the charm-strange baryon is measured for the first time at the LHC via its semileptonic decay into e in pp collisions at TeV with the ALICE detector. The transverse momentum () differential cross section multiplied by the branching ratio is presented in the interval at mid-rapidity, . The transverse momentum dependence of the baryon production relative to the meson production is compared to predictions of event generators with various tunes of the hadronisation mechanism, which are found to underestimate the measured cross-section ratio. peerReviewed
Measurement of electrons from semileptonic heavy-flavor hadron decays in pp collisions at √s = 2.76 TeV
2015
The pT-differential production cross section of electrons from semileptonic decays of heavy-flavor hadrons has been measured at midrapidity in proton-proton collisions at ffiffi s p ¼ 2.76 TeV in the transverse momentum range 0.5 < pT < 12 GeV=c with the ALICE detector at the LHC. The analysis was performed using minimum bias events and events triggered by the electromagnetic calorimeter. Predictions from perturbative QCD calculations agree with the data within the theoretical and experimental uncertainties. peerReviewed