Search results for " CERN"
showing 10 items of 50 documents
Measurements of forward proton production with incident protons and charged pions on nuclear targets at the CERN Proton Synchroton
2010
Measurements of the double-differential proton production cross-section d(2 sigma)/dpd Omega in the range of momentum 0.5 GeV/c <= p < 8.0 GeV/c and angle 0.05 rad <= theta < 0.25 rad in collisions of charged pions and protons on beryllium, carbon, aluminium, copper, tin, tantalum, and lead are presented. The data were taken with the large acceptance HARP detector in the T9 beam line of the CERN Proton Synchrotron. Incident particles were identified by an elaborate system of beam detectors and impinged on a target of 5% of a nuclear interaction length. The tracking and identification of the produced particles was performed using the forward spectrometer of the HARP experiment. Results are o…
The Nuclear astrophysics program at n_TOF (CERN)
2017
An important experimental program on Nuclear Astrophysics is being carried out at the n_TOF since several years, in order to address the still open issues in stellar and primordial nucleosynthesis. Several neutron capture reactions relevant to s-process nucleosynthesis have been measured so far, some of which on important branching point radioisotopes. Furthermore, the construction of a second experimental area has recently opened the way to challenging measurements of (n, charged particle) reactions on isotopes of short half-life. The Nuclear Astrophysics program of the n_TOF Collaboration is here described, with emphasis on recent results relevant for stellar nucleosynthesis, stellar neut…
Nuclear data activities at the n_TOF facility at CERN
2016
International audience; Nuclear data in general, and neutron-induced reaction cross sections in particular, are important for a wide variety of research fields. They play a key role in the safety and criticality assessment of nuclear technology, not only for existing power reactors but also for radiation dosimetry, medical applications, the transmutation of nuclear waste, accelerator-driven systems, fuel cycle investigations and future reactor systems as in Generation IV. Applications of nuclear data are also related to research fields as the study of nuclear level densities and stellar nucleosynthesis. Simulations and calculations of nuclear technology applications largely rely on evaluate…
Measurement of the 238U(n, γ) cross section up to 80 keV with the Total Absorption Calorimeter at the CERN n_TOF facility
2017
The radiative capture cross section of a highly pure (99.999%), 6.125(2) grams and 9.56(5)×10^−4 atoms/barn areal density 238U sample has been measured with the Total Absorption Calorimeter (TAC) in the 185 m flight path at the CERN neutron time-of-flight facility n_TOF. This measurement is in response to the NEA High Priority Request list, which demands an accuracy in this cross section of less than 3% below 25 keV. These data have undergone careful background subtraction, with special care being given to the background originating from neutrons scattered by the 238U sample. Pileup and dead-time effects have been corrected for. The measured cross section covers an energy range between 0.2 …
Search for diphoton events with large missing transverse energy in 7 TeV proton-proton collisions with the ATLAS detector.
2011
A search for diphoton events with large missing transverse energy is presented. The data were collected with the ATLAS detector in proton-proton collisions at √s=7 TeV at the CERN Large Hadron Collider and correspond to an integrated luminosity of 3.1 pb−1. No excess of such events is observed above the standard model background prediction. In the context of a specific model with one universal extra dimension with compactification radius R and gravity-induced decays, values of 1/R<729 GeV are excluded at 95% C. L., providing the most sensitive limit on this model to date.
Search for an excess of events with an identical flavour lepton pair and significant missing transverse momentum in root s=7 TeV proton-proton collis…
2011
Results are presented of a search for supersymmetric particles decaying into final states with significant missing transverse momentum and exactly two identical flavour leptons (e or mu) of opposite charge in sqrt{s}=7 TeV collisions at the Large Hadron Collider. This channel is particularly sensitive to supersymmetric particle cascade decays producing flavour correlated lepton pairs. Flavour uncorrelated backgrounds are subtracted using a sample of opposite flavour lepton pair events. Observation of an excess beyond Standard Model expectations following this subtraction procedure would offer one of the best routes to measuring the masses of supersymmetric particles. In a data sample corres…
Charm-quark fragmentation fractions and production cross section at midrapidity in pp collisions at the LHC
2022
Physical review / D 105(1), L011103 (2022). doi:10.1103/PhysRevD.105.L011103
A large-area modular electromagnetic shower detector for the CERN intersecting storage rings
1979
The authors describe the design and performances large-area (13 m/sup 2/) shower detector built for an experiment at the CERN ISR to detect electrons and gamma rays with energies up to 4 GeV. The main characteristics of the detector are: a) linearity of the energy response from 0.5 to 4 GeV; b) good energy, time and space resolutions; c) modularity of the mechanical assembly; d) low cost of construction. (3 refs).
Evidence of the same multiparticle production mechanism in p−p collisions as in e+e− annihilation
1980
The split-field magnet spectrometer at the CERN intersecting storage rings was used to measure, in p-p collisions at square root s=62 GeV, the inclusive momentum distribution of the charged particles produced in the same hemisphere as the leading proton (x>0.4). A new scaling variable was introduced in order to take into account baryon-number conservation effects in p-p interactions. It is shown that distributions in this variable are in good agreement with the momentum distribution of the hadrons produced in e/sup +/e/sup -/ annihilation. The results suggest that the multiparticle production mechanism in p-p collisions is the same as in e/sup +/e/sup -/ provided that the effects of baryon-…
Search for quarks in proton-proton interactions at √s = 52.5 GeV
1978
The results of an experiment to search for quarks in pp collisions, at a total centre-of-mass energy √s = 52.5 GeV, are reported. The experiment was sensitive to fractionally charged particles with 0.035e ⩽ |Q| ⩽ 0.67e,β =v/c ⩾ 0.1, and masses up to 21 GeV/c2. The 90% confidence level on the ratio «quark flux/charged-particle flux» is 5.11 · 10−11 for |Q| = 1/3e. This value holds true for particles produced with a mean transverse momentum of 0.4 GeV/c.