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.
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.
123565774
Alpha and Beta at the B Factories
We review recent experimental results on time-dependent CP asymmetries in the B system from the BABAR and Belle experiments. Measurements of the {alpha} and {beta} angles of the Unitarity Triangle of the CKM matrix are discussed. These measurements constitute stringent tests of the Standard Model, and are also used to search for new physics.
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.
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.
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.
120319443
Associated multiplicities in proton-proton collisions with a charged hadron atX=0 at the CERN ISR
SummaryCharged-particle multiplicities and angular distributions associated with a π±, K±, p and 

$$
\bar p
$$

 produced at 90°, have been measured at the CERN ISR. The triggering particle was identified by a magnetic spectrometer, within a range of transverse laboratory momentumpT which was different for different particles: 0.075<pT<3.0 GeV/c for pions, 0.075<pT<1.5 GeV/c for kaons, 0.075<pT<3.0 GeV/c for protons and antiprotons. Associated multiplicities have been obtained as a function ofpT at the different ISR beam energies. The distributions of the associated particles have been studied as functions of the azimuthal angleϕ and of the pseudorapidityη. In the high-pT region associated multiplicities increase for all particle types approximately linearly withpT. The momentum of a high-pT particle is seen to be balanced over a wide cone ofϕ andη in the opposite hemisphere. An increase in the multiplicities of secondaries in the same hemisphere near the triggering particle is also observed for the high-pT baryons. At lowpT there is an increase in associated multiplicity on the same side as the transverse momentum of the pion approaches zero.RiassuntoSi presentano le misure effettuate agli ISR del CERN delle molteplicità e distribuzioni angolari delle particelle associate a π±, K±, p e 

$$
\bar p
$$

 prodotti a 90°. La particella di trigger è identificata da uno spettrometro magnetico in grado di analizzare i seguenti intervalli di momento trasversopT nel laboratorio: 0.075<pT<3.0 GeV/c per i π, 0.075< <pT<1.5 GeV/c per K e 0.075<pT<3.0 GeV/c per i protoni e gli antiprotoni. Si studiano le molteplicità delle particelle associate in funzione dell’impulso trasversopT delle particelle di trigger alle varie energie dei fasci circolanti negli ISR. Si studiano anche le distribuzioni delle particelle associate in funzione dell’angoloϕ e della pseudorapiditàη. Ad alto impulso trasverso le molteplicità associate crescono pressapoco linearmente con l’impulsopT. L’impulso di una particella ad altopT è bilanciato su un ampio cono in ϕ e η nell’emisfero opposto. Ad altopT e quando la particella di trigger è un barione si osserva una crescità nella molteplicità delle particelle associate nello stesso emisfero e a piccolo angolo Δϕ e δη rispetto al barione di alto impulso. A bassopT la molteplicità delle particelle associate ai π aumenta quandopT tende a zero.РеэюмеB ЦEPHe на ISR были иэмерены множественности эаряженных частиц и угловые распределения, ассоциированные с π±, K±, p и 

$$
\bar p
$$

, рожденными под углом 90°. Триггерные частицы идентифицируются с помошью магнитного спектрометра в области поперечных импульсовpT в лабораторной системе, которая является раэличной для раэличных частиц: 0.075<pT<3.0 ГзB/c для пионов, 0.075<pT<1.5 ГзB/c для каонов, 0.075<pT<3.0 ГзB/c для протонов и антипротонов. Были определены ассоциированные множественности как функцииpT при раэличных знергиях ISR пучка. Было проведено исследование распределений ассоциированных частиц как функций аэимутального углаϕ и псевдобыстротыη. В области больщихpT ассоциированные множественности увеличиваются для всех типов частиц приблиэительно линейно сpT. По-видимому, импульс частиц с больщимиpT является скомпенсированным в щироком конусеϕ иη в противоположной полусфере. Для барионов с больщимиpT также наблюдается увеличение множественностей вторичных частиц в полусфере около триггерной частицы. При малых рT имеет место увеличение ассоциированной множественности в ту же сторону, как и в случае, когда поперечный импульс пиона стремится к нулю.
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%.
120228621
Observation of the Transition $\Upsilon^\prime \to \Upsilon \pi^+ \pi^- \to e^+ e^- \pi^+ \pi^-$
124699225
Total cross-section measurement at the ISR
SummaryWe present the first results of an experiment at the CERN intersecting storage rings, which measures the total cross-section in proton-proton collisions. The equivalent laboratory momenta are 291, 496, 1068 and 1480 GeV/c. We have made a direct measurement of αT as the ratio between the total interaction rate and the machine luminosity. The present paper gives a detailed description of the experimental apparatus and of the analysis procedure. We find that αT increases by about 10% in the energy region studied.RiassuntoSi presentano i primi risultati di un esperimento agli anelli di accumulazione per protoni del CERN, che misura la sezione d'urto totale delle collisioni protone-protone. Gli impulsi equivalenti nel laboratorio sono di 291, 496, 1068 e 1480 GeV/c. Si è eseguita una misura diretta di αT come rapporto fra frequenza totale di interazione e luminosità della macchina. Questo articolo dà una descrizione dettagliata dell'apparato sperimentale e del procedimento di analisi. Si trova che αT aumenta di circa il 10% nell'intervallo di energia studiato.РезюмеМы предлагаем первые результаты эксперимента в ЦЕРНе на встречных накопительных пучках. В эксперименте проводилось измерение полного поперечного сечения в протон-протонных соударениях. Эквивалентный лабораторный импульс составляет 291, 496, 1068 и 1480 ГэВ/с. Мы провели прямое измерение αT как отношения между полной интенсивностью взаимодействия и светимостью машины. В этой работе приводится подробное описание экспериментальной аппаратуры и анализ методики. Мы обнаружили, что αT возрастает на 10% в исследованной области энергий.