P.L. Braccini

Measurement of the total proton-proton cross-section at the ISR

Abstract We present the first results of a measurement of the total cross-section σ T in proton-proton collisions at equivalent laboratory momenta between 291 and 1480 GeV/ c at the CERN Intersecting Storage Rings (ISR). The method is based on the measurement of the ratio of the total interaction rate and the machine luminosity. The data show an increase of about 10% in σ T in this energy interval.

Measurement of the polarization parameter in π±p, K±p, pp, and p̄p elastic scattering at 6 GeV/c

Abstract Experimental results are presented for the polarization parameter P 0 in π ± p , K ± p , pp, and p p elastic scattering at 6 GeV/ c , and in the range of the invariant four-momentum transfer squared − t from 0.05 to ∼ 2.0 (GeV/ c ) 2 .

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.

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.

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%.

Polarization in proton-proton elastic scattering at 10, 14 and 17.5 GeV/c

Abstract Data on the polarization parameter in pp elastic scattering in the | t |-range from ∼0.1 to ∼ 2.9 (GeV/ c ) 2 and at 10, 14 and 17.5 GeV/ c are presented.

Measurement of charged particle multiplicities associated with large transverse momentum photons in proton-proton collisions

Abstract We have measured the behaviour or charged-particle multiplicities as a function of the transverse momentum of photons produced at 90° in proton-proton collisions. The data were obtained at the CERN Intersecting Storage Rings (ISR) at a centre-of-mass energy of 53 GeV and cover the transverse momentum range 0

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 durto 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 dellapparato sperimentale e del procedimento di analisi. Si trova che αT aumenta di circa il 10% nellintervallo 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.

Measurement of the polarization parameter in π+p elastic scattering at 10, 14 and 17.5 GeV/c and for | t | ⪅ 2 (GeV/c)2

Abstract Results on polarization in π − p and π + p forward elastic scattering at 10, 14 and 17.5 GeV/ c are presented.

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.