123038966
Measurement of tensor polarization of deuterons from 3He->d+p breakup at momenta from 4.60 to 5.66 GeV/c
The tensor polarization p{sub 20} of deuterons emitted in the {sup 1}H(3{sup 3}He,d{leftrightarrow})X reaction at 0{sup o} in the laboratory system was measured at the Saturne National Laboratory in Saclay using the SPES-4 spectrometer with the HYPOM polarimeter located downstream from its focal plane. The momentum of the detected deuterons was kept fixed at 3.77 GeV/c, while the momentum of the {sup 3}He beam was varied from 4.60 to 5.66 GeV/c, thus providing a range of internal momenta k of the deuteron in {sup 3}He from 0 up to 0.4 GeV/c. The data obtained are compared with theoretical predictions.
118700097
Recent and future measurements of the proton electric form factor
54739743
The aerogel threshold Cherenkov detector for the High Momentum Spectrometer in Hall C at Jefferson Lab
We describe a new aerogel threshold Cherenkov detector installed in the HMS spectrometer in Hall C at Jefferson Lab. The Hall C experimental program in 2003 required an improved particle identification system for better identification of p=K=p, which was achieved by installing an additional threshold Cherenkov counter. Two types of aerogel with n 1⁄4 1:030 and n 1⁄4 1:015 allow one to reach 10 3 proton and 10 2 kaon rejection in the 1–5GeV/c momentum range with pion detection efficiency better than 99% (97%). The detector response shows no significant position dependence due to a diffuse light collection technique. The diffusion box was equipped with 16 Photonis XP4572 photo multiplier tubes (PMTs). The mean number of photo-electrons in saturation was 16 and 8, respectively. This allows even for separation of slower particles slightly above threshold. r 2005 Elsevier B.V. All rights reserved. PACS: 29.40.Ka; 25.30.Rw
29593010
Pion absorption above the Delta (1232) resonance.
Two-proton and three-proton inclusive [pi][sup +] absorption cross sections were measured for incident pion energies from 250 to 500 MeV on targets of [sup 12]C, [sup 58]Ni, [sup 90]Zr, [sup 118]Sn, and [sup 208]Pb using a large solid angle bismuth germanate detector array. Pion absorption events leading to three or more protons in the final state were observed to become more significant with increasing incident pion energy and were dominant at 500 MeV. The total absorption cross sections were inferred from analyses of the data with uncertanties of approximately 25%.
119878792
Measurement of the ratio of the proton's electric to magnetic form factors by recoil polarization
The longitudinal and transverse polarizations of the outgoing proton were measured for the reaction {sup 1}H(e,e' p) at four-momentum transfer squared of 0.5 to 3.5 GeV{sup 2}. The ratio of the electric to magnetic form factors of the proton is proportional to the ratio of the transverse to longitudinal polarizations.
43065058
Pion absorption in light nuclei.
Cross sections have been measured for proton emission following ${\mathrm{\ensuremath{\pi}}}^{+}$ absorption on $^{6}\mathrm{Li}$, $^{7}\mathrm{Li}$, $^{9}\mathrm{Be}$, $^{10}\mathrm{B}$, $^{11}\mathrm{B}$, $^{12}\mathrm{C}$, and $^{13}\mathrm{C}$, for pion kinetic energies of 50, 100, 140, and 180 MeV using a large-solid-angle bismuth germanate detector array.
123029644
Observation of short-lived particles produced in high energy neutrino interactions
Abstract Examination of a sample of 89 high-energy, neutrino-induced dilepton events produced in the Fermilab 15 ft bubble chamber has resulted in the direct observation of the production and visible semi-leptonic decay of short-lived particles. One charged decay, two neutral decays, and one decay candidate of undetermined charge are found. Assuming these events and the remaining dilepton signal result from D meson decays, we obtain τ D + = 2.5 −1.5 +3.5 × 10 −13 s and τ D 0 = 3.5 −1.7 +3.5 × 10 −13 s, using a maximum likelihood analysis.
120839233
Search for high-energy tau-neutrino interactions
Kinematic selection criteria are developed for separating tau-neutrino charged-current interactions from a large background of muon- and electron-neutrino interactions. The criteria are designed to detect the three-prong decay mode of the $\ensuremath{\tau}$ lepton and rely on the three-particle combination's transverse momentum being anticorrelated with the tr\'ansverse momentum of the other visible particles and being correlated with the missing transverse momentum. The criteria are applied to a sample of events from an exposure of the Fermilab 15-ft bubble chamber to the quadrupole triplet neutrino beam. The average event energies for this beam are 90 GeV for neutrino and 60 GeV for antineutrino events. The $14 \ensuremath{\tau}$ candidates selected agree with the calculated background of 14.3\ifmmode\pm\else\textpm\fi{}1.2. An upper limit on the probability of muon neutrinos oscillating into tau neutrinos of 0.053 is obtained.
47564335
Level-2 Calorimeter Trigger Upgrade at CDF
The CDF Run II level-2 calorimeter trigger is implemented in hardware and is based on a simple algorithm used in Run I. This system has worked well for Run II at low luminosity. However, as the Tevatron instantaneous luminosity increases, the limitation due to the simple algorithm starts to become clear. In this paper, we will present an upgrade path to the level-2 calorimeter trigger system at CDF. This upgrade approach is based on the Pulsar board, a general purpose VME board developed at CDF and used for upgrading both the level-2 tracking and the Level-2 global decision crate. This paper will describe the design, hardware and software implementation, as well as the advantages of this approach over the existing system.
121659740
The CDF level 2 calorimetric trigger upgrade
Abstract CDF II upgraded the calorimeter trigger to cope with the higher detector occupancy due to the increased Tevatron instantaneous luminosity ( ∼ 2.8 × 10 32 cm - 2 s - 1 ) . While the original system was implemented in custom hardware and provided to the L2 trigger a limited-quality jet clustering performed using a reduced resolution measurement of the transverse energy in the calorimeter trigger towers, the upgraded system provides offline-quality jet reconstruction of the full resolution calorimeter data. This allows to keep better under control the dependence of the trigger rates on the instantaneous luminosity and to improve the efficiency and purity of the trigger selections. The upgraded calorimeter trigger uses the general purpose VME board Pulsar, developed at CDF II and already widely used to upgrade the L2 tracking and L2 decision systems. A battery of Pulsars is used to merge and send the calorimeter data to the L2 CPUs, where software-implemented algorithms perform offline-like clustering. In this paper we review the design and the performance of the upgraded system.
117310029
Simulation of LiCAS Error Propagation
Linear Collider Alignment and Survey (LiCAS) R&D group is proposing a novel automated metrology instrument dedicated to align and monitor the mechanical stability of a future linear high energy e + e collider. LiCAS uses Laser Straightness Monitors (LSM) and Frequency Scanning Interferometry (FSI) [2, 3] for straightness and absolute distance measurements, respectively. This paper presents detailed simulations of a LiCAS system operating inside a Rapid Tunnel Reference Surveyor (RTRS train). With the proposed design it is feasible to achieve the required vertical accuracy of the order of O(200)µm over 600m tunnel sections meeting the specification for the TESLA collider [4]. 1 Principle of the LICAS-RTRS train operation In figure 1 the schematic view of the LiCAS train operating in the accelerator tunnel is presented. The train is composed of 6 cars, the distance between the centres of neighbouring cars is � 4.5m. Each car is equipped with 4 CCD cameras and two beam splitters (BS) constituting the straightness monitor. The straightness monitor measures the transverse translation (Tx,Ty) and transverse rotation (Rx,Ry) with respect to a z axis defined by the laser beam passing through all cars in a vacuum pipe. The laser beam is reflected back using the retro-reflector (RR) located in the last car, illuminating the upper CCD cameras of the straightness monitors. 6 FSI lines placed in the same vacuum pipe between each pair of cars are responsible for the distance measurement along the z axis (Tz). In addition a clinometer located on each car provides a measurement of rotation around the z axis (Rz). When the train stops in front of the wall markers it firstly measures the relative position and rotation of all cars with respect to the first car. This defines the local reference frame of the train in which the location of the wall mounted reference markers are measured next. This procedure is repeated for each train stop. Each marker is measured up to 6 times. Finally the coordinates of each marker, expressed in the local train frames are transformed to the frame of the first train (the global frame) by fitting them to each other under the constraint that wall markers have not moved during the entire measurement. 2 Opto-geometrical model of the LICAS-RTRS train In order to study the expected precision on the position reconstruction of the tunnel reference markers a simulation of the LiCAS survey train was performed. To describe the sensing parts of the train the Simulgeo [5] package was used which allows for modelling