15 research outputs found
The T2K ND280 Off-Axis Pi-Zero Detector
The Pi-Zero detector (P{\O}D) is one of the subdetectors that makes up the
off-axis near detector for the Tokai-to-Kamioka (T2K) long baseline neutrino
experiment. The primary goal for the P{\O}D is to measure the relevant cross
sections for neutrino interactions that generate pi-zero's, especially the
cross section for neutral current pi-zero interactions, which are one of the
dominant sources of background to the electron neutrino appearance signal in
T2K. The P{\O}D is composed of layers of plastic scintillator alternating with
water bags and brass sheets or lead sheets and is one of the first detectors to
use Multi-Pixel Photon Counters (MPPCs) on a large scale.Comment: 17 pages, submitted to NIM
Comparing proton momentum distributions in and 3 nuclei via H H and He measurements
We report the first measurement of the reaction cross-section
ratios for Helium-3 (He), Tritium (H), and Deuterium (). The
measurement covered a missing momentum range of
MeV, at large momentum transfer (
(GeV)) and , which minimized contributions from non
quasi-elastic (QE) reaction mechanisms. The data is compared with plane-wave
impulse approximation (PWIA) calculations using realistic spectral functions
and momentum distributions. The measured and PWIA-calculated cross-section
ratios for He and H extend to just above the typical nucleon
Fermi-momentum ( MeV) and differ from each other by , while for He/H they agree within the measurement accuracy of
about 3\%. At momenta above , the measured He/H ratios differ from
the calculation by . Final state interaction (FSI) calculations
using the generalized Eikonal Approximation indicate that FSI should change the
He/H cross-section ratio for this measurement by less than 5\%. If
these calculations are correct, then the differences at large missing momenta
between the He/H experimental and calculated ratios could be due to the
underlying interaction, and thus could provide new constraints on the
previously loosely-constrained short-distance parts of the interaction.Comment: 8 pages, 3 figures (4 panels
Design, Construction, and Performance of the GEM based Radial Time Projection Chamber for the BONuS12 Experiment with CLAS12
International audienceA new radial time projection chamber based on Gas Electron Multiplier amplification layers was developed for the BONuS12 experiment in Hall B at Jefferson Lab. This device represents a significant evolutionary development over similar devices constructed for previous experiments, including cylindrical amplification layers constructed from single continuous GEM foils with less than 1% dead area. Particular attention had been paid to producing excellent geometric uniformity of all electrodes, including the very thin metalized polyester film of the cylindrical cathode. This manuscript describes the design, construction, and performance of this new detector
The T2K experiment
The T2K experiment is a long baseline neutrino oscillation experiment. Its main goal is to measure the last unknown lepton sector mixing angle Ξ13 by observing Μe appearance in a ΜΌ beam. It also aims to make a precision measurement of the known oscillation parameters, and sin22Ξ23, via ΜΌ disappearance studies. Other goals of the experiment include various neutrino cross-section measurements and sterile neutrino searches. The experiment uses an intense proton beam generated by the J-PARC accelerator in Tokai, Japan, and is composed of a neutrino beamline, a near detector complex (ND280), and a far detector (Super-Kamiokande) located 295 km away from J-PARC. This paper provides a comprehensive review of the instrumentation aspect of the T2K experiment and a summary of the vital information for each subsystem
Revealing the structure of light pseudoscalar mesons at the electronâion collider
International audienceThe questions of how the bulk of the Universeâs visible mass emerges and how it is manifest in the existence and properties of hadrons are profound, and probe the heart of strongly interacting matter. Paradoxically, the lightest pseudoscalar mesons appear to be key to a further understanding of the emergent mass and structure mechanisms. These mesons, namely, the pion and kaon, are the NambuâGoldstone boson modes of quantum chromodynamics (QCD). Unravelling their partonic structure and the interplay between emergent and Higgs-boson mass mechanisms is a common goal of three interdependent approachesâcontinuum QCD phenomenology, lattice-regularised QCD, and the global analysis of parton distributionsâlinked to experimental measurements of hadron structure. Experimentally, the anticipated electronâion collider will enable a revolution in our ability to study pion and kaon structures, accessed by scattering from the âmeson cloudâ of the proton through the Sullivan process. With the goal of enabling a suite of measurements that can address these questions, we examine key reactions that identify the critical detector-system requirements needed to map tagged pion and kaon cross-sections over a wide range of kinematics. The excellent prospects for extracting pion structural, functional, and form-factor data are outlined, and similar prospects for kaon structures are discussed in the context of a worldwide programme. The successful completion of the programme outlined herein will deliver deep, far-reaching insights into the emergence of pions and kaons, their properties, and their role as QCDâs Goldstone boson modes
Jefferson Lab Hall C: Precision Physics at the Luminosity Frontier
Over the last three decades, Hall C has been a key contributor to progress in the understanding of hadron structure and interactions. An outline of a potential future Hall C physics program focused on precision measurements of small cross sections is presented. A detailed overview of this unique facility, whose flexible configuration allows many opportunities for new experimental equipment that help address a wide range of questions in hadronic physics, is included as well
First Measurement of the EMC Effect in B and B
International audienceThe nuclear dependence of the inclusive inelastic electron scattering cross section (the EMC effect) has been measured for the first time in B and B. Previous measurements of the EMC effect in nuclei showed an unexpected nuclear dependence; B and B were measured to explore the EMC effect in this region in more detail. Results are presented for Be, B, B, and C at an incident beam energy of 10.6~GeV. The EMC effect in the boron isotopes was found to be similar to that for Be and C, yielding almost no nuclear dependence in the EMC effect in the range . This represents important, new data supporting the hypothesis that the EMC effect depends primarily on the local nuclear environment due to the cluster structure of these nuclei
First Measurement of the EMC effect in <math><mmultiscripts><mi mathvariant="normal">B</mi><mprescripts/><none/><mn>10</mn></mmultiscripts></math> and <math><mmultiscripts><mi mathvariant="normal">B</mi><mprescripts/><none/><mn>11</mn></mmultiscripts></math>
International audienceThe nuclear dependence of the inclusive inelastic electron scattering cross section (the EMC effect) has been measured for the first time in B10 and B11. Previous measurements of the EMC effect in Aâ€12 nuclei showed an unexpected nuclear dependence; B10 and B11 were measured to explore the EMC effect in this region in more detail. Results are presented for Be9, B10, B11, and C12 at an incident beam energy of 10.6 GeV. The EMC effect in the boron isotopes was found to be similar to that for Be9 and C12, yielding almost no nuclear dependence in the EMC effect in the range A=4â12. This represents important new data supporting the hypothesis that the EMC effect depends primarily on the local nuclear environment due to the cluster structure of these nuclei