123715849
Two-body correlations in high-energy proton-proton interactions
SummaryA study of about 105 proton-proton interactions at
$$\sqrt s = 52.5 GeV$$
 was performed by using the ISR Split Field Magnet. Correlations between particles pairs with like and unlike charges were studied in terms of six variables. The main conclusions are i) the difference in the azimuthal asymmetry parameter between unlike- and like-charge pairs shows up at invariant masses between 500 and 1200 MeV,i.e. in the region of the well-known resonances; ii) a supershort (Δy≤0.5) correlation effect exists for unlike- as well as for like-charge pairs; iii) the azimuthal asymmetry parameter remains positive (back-to-back configurations are preferred) even for every large values of the rapidity variables, independent of the charge configurations. The 105 interactions represent a high statistical sample of events without any sort of trigger bias, such as highpT, multiplicity, or energy.RiassuntoSi sono studiate circa 105 interazioni protone-protone a
$$\sqrt s = 52.5 GeV$$
 GeV usando lo Split Field Magnet degli ISR. Si sono analizzate le correlazioni tra coppie di particelle di carica elettrica uguale ed opposta in funzione di sei variabili. Le principali conclusioni sono: i) la differenza nel parametro di asimmetria azimutale tra coppie di carica opposta ed uguale si manifesta per valori della massa invariante tra 500 e 1200 MeV, cioè nella regione delle risonanze ben note; ii) esiste un effetto di correlazione delle coppie di carica opposta ed uguale per valori estremamente piccoli di Δy (Δy≤0.5); iii) il parametro di asimmetria azimutale rimane positivo (le configurazioni «back-to-back» sono privilegiate) anche per valori molto grandi di rapidità, indipendentemente dagli stati di carica. Le 105 interazioni studiate costituiscono un campione, ad alta statistica, di eventi senza condizioni particolari di «trigger», come altopT, molteplicità o energia.РезюмеПроведено изучение 105 протон-протонных взаимодействий при ГэВ. С помощью шести переменных исследуются корреляции между парами частиц с одинаковыми и неодинаковыми зарядами. Получены следующие результаты: 1) обнаружена разность в параметре азимутальной асимметрии для пар неодинаковых зарядов и для пар одинаковых зарядов при инвариантных массах между 500 и 1200 МэВ, т.е. в области хорошо известных резонансов; 2) обнаружен эффект суперкоротких корреляций (Δy=0.5) для пар неодиноковых зарядов и для пар одиаковых зарядов; 3) параметр азимутальной асимметрии остается положительным даже для очень больших значений переменных быстроты вне зависимости от зарядовой конфигурации. 105 взаимодействий представляют пример высокой статистики событий.
117276470
New ISR physics: Heavy flavors and multihadronic final states
120145616
The inclusive transverse-momentum distribution in hadronic systems produced in proton-proton collisions
Summary. The single.particle inclusive transverse-momentum distribution in the multiparticle systems produced in low-1~T proton-proton interactions at ~- 30 and 62 GoV has been studied. The analysis was performed removing from the final state the leading proton and redefining the effective hadronie energy available for particle production. Excellent agreement for effective hadronic energies up to 13 GoV is found between (pp) and (e+e-). At higher energy the (pp) data show a less pronounced growth than the (e+e -) data.
124305736
Search for fractionally charged particles produced in proton-proton collisions at the highest ISR energy
SummaryThe results of an experiment to search for quarks at the CERN ISR, at a total centre-of-mass energy √s=62.2 GeV, are reported. The experiment was sensitive to fractionally charged particles with 0.035e≤|Q|≤0.67e, β=v/c≥0.1 and masses up to 26 GeV/c2. The 90% confidence level on the ratio «quark flux/charged flux» is 1.78·10−9 forQ=+(1/3)e and 1.05·10−9 forQ=−(1/3)e. These values hold true for production processes with transverse momentap⊥≃0.4 GeV/c.RiassuntoSi presentano i risultati di un esperimento per la ricerca di quarks presso gli ISR del CERN, ad un valore dell'energia totale nel centro di massa √s=62.2 GeV. L'esperimento era sensibile a particelle con carica frazionaria nell'intervallo 0.035e≤|Q|≤0.67e, con β=v/c≧0.1 e masse fino a 26 GeV/c2. Il valore del rapporto «flusso di quarks/flusso di particelle cariche», con un livello di confidenza del 90%, è 1.78·10−9 perQ=+(1/3)e, e 1.05·10−9 perQ=−(1/3)e. Questi valori si applicano a processi di produzione con impulsi trasversip⊥≃0.4 GeV/c.
118133322
A prediction for the total charge multiplicity in hadronic interactions at extreme high energies
121671301
A large-area modular electromagnetic shower detector for the CERN intersecting storage rings
Abstract We describe the design and performances of a large-area (13 m 2 ) shower detector built for an experiment at the CERN ISR to detect electrons and gamma rays with energies up to 4 GeV. The main characteristics of the detector are: a) linearity of the energy response from 0.5 to 4 GeV; b) good energy, time and space resolutions; c) modularity of the mechanical assembly; d) low cost of construction.
123498730
CMS tracker performance
Abstract The Compact Muon Solenoid (CMS) experiment is a multipurpose high energy physics detector operated at the CERN Large Hadron Collider (LHC) near Geneva, Switzerland. The current status and performance of the CMS silicon tracker after 2 years of p–p collisions at s = 7 TeV are reviewed.
102340714
CMS Tracker, ECAL and Pixel Optical Cabling: Installation and Performance Verification
The installation of 52304 optical links for the readout and control of the CMS Tracker, ECAL and Pixel detectors is complete. 768 96-way optical cables were installed and tested using an optical time-domain reflectometer. The testing was followed by connections at high density optical fibre patchpanels. Finally, a further round of testing and troubleshooting following feedback from system commissioning with the Tracker Data Acquisition was carried out. Over 90% of the faults found were recovered, resulting overall in only 0.1% of dead optical link channels in the CMS Tracker.
121781476
First performance studies of a pixel-based trigger in the CMS experiment
An important tool for the discovery of new physics at LHC is the design of a low level trigger with an high power of background rejection. The contribution of pixel detector to the lowest level trigger at CMS is studied focusing on low-energy jet identification, matching the information from calorimeters and pixel detector. In addition, primary vertex algorithms are investigated. The performances are evaluated in terms of, respectively, QCD rejection and multihadronic jets final states efficiency.
110850685
First level trigger using pixel detector for the CMS experiment
A proposal for a pixel-based Level 1 trigger for the Super-LHC is presented. The trigger is based on fast track reconstruction using the full pixel granularity exploiting a readout which connects different layers in specific trigger towers. The trigger will implement the current CMS high level trigger functionality in a novel concept of intelligent detector. A possible layout is discussed and implications on data links are evaluated.