14677203
Study of Solid State Photon Detectors Read Out of Scintillator Tiles
We present preliminary results on efficiency and light collection uniformity read out performances of different assemblies of scintillator tiles, coupled with solid state photon detectors of different make. Our test beam data suggest that the use of 2 mm scintillator tiles without wavelength shifting fibers may be possible in an ILC hadron calorimeter.
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.
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.
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.
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.
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.
117089603
Measurements of the A2- and A2+ Mass Spectra
126286321
Observation of the Upsilon''' at CESR
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.
121892713
Precision measurement of proton-proton total cross section at the CERN intersecting storage rings
Abstract The measurement of the proton-proton total cross section performed by the CERN-Pisa-Rome-Stony Brook Collaboration at the CERN ISR is discussed in detail. The total interaction rate, the elastic scattering rate in the forward direction, and the machine luminosity were measured simultaneously to obtain three different determinations of the total cross section. Consistent results were found, which made it possible to prove the reliability of the Van der Meer luminosity calibration within +-0.9% and to achieve a precision of +-0.6% in the measurement of the total cross section.
118729839
Measurement of two-particle semi-inclusive rapidity distributions at the CERN ISR
SummaryWe present data on the semi-inclusive distributions of rapidities of secondary particles produced in pp collisions at very high energies. Our experiment was performed at the CERN Intersecting Storage Rings (ISR). The data given here, at centre-of-mass energies of √s=23 and 62 GeV, include the single-particle distributions and two-particle correlations. The semi-inclusive correlations show pronounced short-range correlation effects which have a width considerably narrower than in the case of inclusive correlations. We show that these short-range effects can be understood empirically in terms of three parameters whose energy and multiplicity dependence are studied. The data support the picture of multiparticle production in which clusters of small multiplicity and small dispersion are emitted with subsequent decay into hadrons.RiassuntoVengono presentati dati sulle distribuzioni inclusive in rapidità dei secondari carichi prodotti nelle collisioni protone-protone ad altissime energie. L’esperimento è stato eseguito agli Anelli ad Intersezione (ISR) del CERN. I dati, ad una energia √s=23 e 62 GeV nel centro di massa, comprendono le distribuzioni di particella singola e le correlazioni a due particelle per fissa molteplicità carica, come anche le correlazioni inclusive a due particelle. Le correlazioni semi inclusive mostrano forti effetti di correlazione a breve distanza, che hanno una larghezza molto più piccola che nel caso delle correlazioni inclusive. Nel lavoro si fa vedere che questi effetti a breve distanza possono essere capiti empiricamente in funzione di tre parametri di cui si studia la dipendenza dall’energia e dalla molteplicità. I dati favoriscono la descrizione della produzione a molti corpi in cui vengono emessi agglomerati di piccola molteplicità e piccola dispersione, che successivamente decadono in adroni.РеэюмеВ работе приводятся данные для полуинклюэивных распределений вторичных частиц, рожденных в рр соударениях при очень высоких знергиях. Нащ зксперимент был проиэведен на встречных накопительных кольцах в ЦЕРНе. Полученные в работе данные при знергиях в системе центра масс √s=23 и 62 ГзВ включают одночастичные распределения и двухчастичные корреляции при фиксированной множественности эаряженных частиц п, а также инклюэивные двухчастичные корреляции. Полуинклюэивные корреляции обнаруживают явно выраженные зффекты короткодействуюших корреляций, которые обладают щириной эначительно меньщей, чем в случае инклюэивных корреляций. Мы покаэываем, что зти короткодействуюшие зффекты могут быть общяснены змпрически в терминах трех параметров. Обсуждается эависимость зтих параметров от знергии и множественности. Полученные данные подтверждают картину множественного рождения, в которой испускаются кластеры с малой множественностью и малой дисперсией с последуюшим распадом в адроны.