123574900
Measurement of recoil proton polarizations in the electrodisintegration of deuterium by polarized electrons
Abstract In order to test modern theories of two-nucleon bound and scattering states, we have measured the spin polarization of ejectile protons in the electrodisintegration reaction d( e → ,e′ p → )n . Compared with spin-averaged observations, these observables offer the potential of enhanced sensitivity to details of the reaction process. The experiment was carried out in quasielastic kinematics ( q μ q μ =−2m p ω=−0.38 GeV 2 /c 2 ). Protons were detected at two angles corresponding to neutron recoil momenta p r of 0 and 100 MeV/c. Full nonrelativistic calculations of the polarization transfer components s l and s t , including leading order relativistic contributions, describe our measurements well, but calculations of the induced polarization s n at p r =100 MeV/c underpredict the experimental result.
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.
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%.
118914530
Measurement of Analyzing Powers for Polarized Proton Scattering on CH2 Target at Proton Momentum Range from 1.75 to 5.3 GeV/c
We report a new measurement of analyzing powers for the reaction p + CH2 → one charged particle +X, at proton momenta of 1.75, 3.8, 4.5 and 5.3 GeV/c. These results extend the existing data basis, necessary for proton polarimetry at intermediate energy, and confirm the feasibility of an extended polarimeter based on this process. The experiment is performed at the accelerator complex of the JINR‐LHE (Dubna).
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.
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
106619516
Influence of luminosity leveling on the CDF-II B-Physics program
The effective bandwidth of the CDF-II level 1 trigger is approximately 25 kHz. Some of this bandwidth is used to record events that form the data sets used by the high p{sub T} physics analyses. The remaining bandwidth is used by triggers that are sensitive to hadronic B decays and provide one of the most important samples used for the study of B{sub s}{sup 0} mixing. At high luminosities, the hadronic B triggers have rates that greatly exceed the available bandwidth. Rather than incur large dead-times associated with these excessive rates, these B triggers are prescaled to limit the total trigger rate to the effective level 1 trigger bandwidth. The prescales are dynamically adjusted as the store progresses so that all of the bandwidth that is not used for the high p{sub T} physics program is used to record hadronic B triggers. In principle, the luminosity could be held at a more constant level throughout the store in such a way that the integrated luminosity would be the same as that obtained from a normal store. It has been suggested that this would allow B triggers to be recorded with lower prescales and consequently with higher B{sub s}{sup 0} signal efficiencies. This note describes a parametric model of the high p{sub T} and hadronic B triggers used by CDF and compares the yields of reconstructed B{sub s}{sup 0} decays that would result with and without luminosity leveling.
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
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.
145877714
The LiCAS-RTRS - A Rapid and Cost Efficient Survey System for the ILC
A vertically stored can dispenser having the capability to retain multiple size food cans and provide easy access to the various size can channels. The dispenser can be attached to a lazy susan rotary base or attached to a slide-out cabinet dispenser device. The multiple size can channels can be interchanged.