120292237
Test of a small prototype of the KLOE drift chamber in magnetic field
Abstract We report on a beam test of a small prototype of the KLOE drift chamber in magnetic field. The chamber was operated with a 90% He–10% iC 4 H 10 gas mixture. Drift space–time relations were studied. The average spatial resolution is about 110 μm in the absence of magnetic field and 120 μm in a 0.6 T magnetic field. Measurements of the primary ionization and drift velocity are reported. The measurement of d E /d x in a He-based gas mixture is also discussed.
56098294
Review of measurements of the angles of the CKM matrix from the BaBar experiment
Experimental results on CP violation measurements in the B meson system from the BABAR experiment at the PEP-II asymmetric B Factory are reviewed.
16384620
CKM-UT Angles: Mixing And CP Violation at the B Factories
We review the experimental status of the angles of the Unitarity Triangle of the CKM matrix, as measured by the BABAR and Belle experiments. The B Factories have demonstrated since the beginning of this decade that CP violation in the B meson system is consistent with the Standard Model (SM) description in terms of the complex phase in the three-by-three Cabibbo-Kobayashi-Maskawa (CKM) matrix. With one single phase, the SM predicts clear patterns for quark mixing and CP violations, to be satisfied by all processes.
110466342
Performance and Aging Studies of BaBar Resistive Plate Chambers
The BaBar detector is currently operating nearly 200 Resistive Plate Chambers (RPCs), constructed as part of an upgrade of the forward endcap muon detector in 2002. Although the average RPC efficiency remains high, numerous changes in the RPC performance (increased currents and rates) have been observed. A few of the highest rate RPCs have suffered efficiency losses of more than 15%. Several types of efficiency loss have been observed. Tests with humidified gas have shown that some of the lost efficiency is recoverable. However, efficiency losses in the highest rate regions have not yet improved with humid gases.
120063494
High precision limited streamer drift tubes
Abstract A tracking telescope employing six layers of Al drift tubes 50 cm long, with diameter d = 3 cm and wall thickness 500 μm, has been built and successfully operated with a 40% Ar-60% iC 4 H 10 gas mixture at atmospheric pressure. The tube cells, with a 100 μm thick CuBe wire strung along the axis, enter streamer mode operation at V = 4.6 kV, and feature full efficiency and local resolution of ≤60 μm.
109329842
Improved Particle Identification Using Cluster Counting in a Full-Length Drift Chamber Prototype
Single-cell prototype drift chambers were built at TRIUMF and tested with a ~210MeV/c beam of positrons, muons, and pions. A cluster-counting technique is implemented which improves the ability to distinguish muons and pions when combined with a traditional truncated-mean charge measurement. Several cluster-counting algorithms and equipment variations are tested, all showing significant improvement when combined with the traditional method. The results show that cluster counting is a feasible option for any particle physics experiment using drift chambers for particle identification. The technique does not require electronics with an overly high sampling rate. Optimal results are found with a signal smoothing time of ~5ns corresponding to a ~100MHz Nyquist frequency.
120513565
Measurement of inclusive two-particle rapidity correlations at the ISR
Abstract We present data on two-particle distributions in the approximate rapidity variable η = −1n tan θ /2 for secondaries produced in proton-proton collisions at the CERN Intersecting Storage Rings (ISR). The data at centre-of-mass energies of 23 and 62 GeV show the existence of energy-independent positive, short-range correlations between secondaries within the central region. Deviations from short-range correlation exist when one (or both) of the particles is near the boundary of the available phase space. In part, such deviations are interpreted as the effect of a diffractive-like component in multiparticle production.
119872948
New measurements of proton-proton total cross section at the CERN intersecting storage rings
Abstract Measurements of the proton-proton total cross section have been made with increased precision (±0.6%) over the ISR energy range s =23.5−62.7 GeV . Two different experimental methods gave consistent results, showing that the total cross section increases 10% over the ISR range and in addition that the absolute value of the ISR luminosity can be measured to ±0.9%.
120566615
Absorption of 10 and 13.5 GeV photons
SummaryThe absorption coefficients of photons have been measured at 10 GeV in CH2 and C, and at 13.5 GeV in Li, C, Cu and Pb. The detection system consisted of a pair spectrometer with two total absorption lead glass Čerenkov counters. A band of γ-rays of ±11% around the centre value was used. Within their experimental accuracies of (2÷5)% our results agree with the theoretical values.RiassuntoAbbiamo misurato i coefficienti di assorbimento di fotoni di 10 GeV in CH2 e C, e di fotoni di 13.5 GeV in Li, C, Cu e Pb. L’apparato rivelatore era costituito da uno spettrometro a coppie con due contatori di Čerenkov ad assorbimento totale. È stata usata una banda di raggi γ di ±11% attorno al valore centrale. Entro l’incertezza sperimentale delle misure ((2÷5)%) i nostri risultati sono in accordo con le previsioni teoriche.
121618537
SEARCH FOR NARROW RESONANCES IN THE R REGION.
121331255
Experimental tests of limiting fragmentation at the ISR
Abstract We present direct tests of the hypothesis of limiting fragmentation from an experiment at the CERN Intersecting Storage Rings at centre-of-mass energies between 31 and 53 GeV. Single-particle inclusive distributions and partial multiplicity distributions are observed for the case in which the energy of one beam is fixed while varying the energy of the other beam. Within cones around the beam, limiting fragmentation is shown to be valid.