A.M. Touchard

Further limits on heavy neutrino couplings

Abstract Limits on leptonic mixing matrix elements are inferred from the results of a dedicated neutrino-decay search; an improvement of more than two orders of magnitude is achieved over previous results for a wide range of the neutrino mass.

Search for neutrino decay

Abstract A search to observe neutrino decays has been performed. Its results are used to set limits on the couplings of a hypothetical massive neutrino with the ordinary v e and v μ . An improvement of about two orders of magnitude is obtained over previous limits in a wide range of neutrino masses.

Study of the I=2 ππ scattering from the reaction π−d → π−π−psp at 9.0 GeV/c

Abstract We have studied the I =2, ππ scattering using the classical Chew-Low extrapolation method. Results are given on the cross sections and the phase shifts δ 0 2 , δ 2 2 and δ 4 2 up to 2.2. GeV. δ 0 2 values are -7.8 ∓ 3.0° at the K o mass, -15. ∓ 1.5° at the ϱ mass and -29. ∓ 2.2° of the f o mass. Above the f o mass | δ 0 2 | decreases.

Inclusive neutral kaon and lambda production in 69 GeV pp interactions

Abstract From a study of 180 neutral vees in the hydrogen bubble chamber Mirabell, we have obtained respectively, for the cross sections of the inclusive reactions pp → K 0 X and pp → λ X, 8.4 ± 1.1 and 3.6 ± 0.5 mb. Data presented for the neutral kaons and λ in terms of the invariant cross sections F ( x , p ⊥ , s ) show, when compared with lower and higher energy results, that scaling is approximately valid at our energy for K o and λ production.

Analysis of KK and KKπ resonances produced in pp annihilations at 1.2 GeV/c

Abstract The analysis of 18 900 V O events is presented, with reference to the production of K K and K K π resonances in the three-, four-, five- and six-body final states. It is established that there is a threshold structure in the ( K K ) I=1 state which comes entirely from the decay of K K π resonances, the D O and E O . The S ∗ and E O are definitely observed. The isospin of the D O is confirmed to be 0, J D O ⩾1 and, under the assumption L D ω =0, J D PC =1 ++ . The F 1 is observed in the final state F 1 η O and the analysis of this channel leads to the conclusion that J F 1 PC =1 +− or 2 − In the five-body final state there is some appearance of two-peaks in the D O mas region, but with the present statistics there is no clear evidence for this effect. The cross sections for single and associated resonance production are given.

Anomalous electron production observed in the CERN PS neutrino beam

Abstract Neutrino interactions in a fine-grain calorimeter have been analysed with emphasis on events with associated electromagnetic showers. The good granularity of the detector allows to separate photon from electron showers. The number of events with an electron was found to be about three times larger than expected on the basis of the beam composition. This may be interpreted as due to v μ → v e oscillations.

Two body correlations between negative pions in pp interactions at 69 GeV/c

Abstract Correlations between two π − in pp interactions at 69 GeV/ c are presented in terms of longitudinal and transversal variables. The dominant feature is the existence of a strong shortrange positive correlation between the two π − in the central region.

Study of neutron diffraction dissociation in the reaction π−n→π−π−p at GeV/c

Abstract In the reaction π−d→π−π−ppS at 9 GeV/c the pπ− mass spectrum exhibits, beyond a broad enhancement near the threshold, a production of N∗ 1520 and N∗ 1690. The production mechanism is studied and the difference in dσ/dt between the threshold enhancement and the isobars seems to be well accounted by the variation of the slope versus mass.

Evidence of neutral F1 production in p̄p annihilations at 1.1−1.2 GeV/c

Abstract F 0 1 has been observed in the reaction pp→K 0 1 K ± π ∓ (MM), mainly in the channel pp→F 0 1 η 0 . The quantum numbers of the F 0 1 have been studied. The only assignments compatible with experiment are JPC =1 +− or 2 −+ .

Inclusive and semi-inclusive two-pion correlations in pp collisions at 69 GeV/c

SummaryCorrelations between pions produced in pp collisions at 69 GeV/c are observed both for π−π+ and π−π−. Short-range correlations in rapidity are present fory1⋍y2 in both cases; an enhancement is seen aroundy1=y2=±1. Correlations between transverse variables are linked to those in rapidity for π−π− combinations, whereas the effect is essentially kinematical for π+π−.RiassuntoSi osservano correlazioni fra pioni prodotti nelle collisioni pp a 69 GeV/c sia per π−π+ che per π−π−. Correlazioni di breve raggio in rapidità sono presenti pery1⋍y2 in entrambi i casi; si nota un aumento attorno ay1=y2=± 1. Le correlazioni fra le variabili trasversali sono collegate a quelle in rapidità per le combinazioni di π−π−, mentre l’effetto è essenzialmente cinematico per π+π−.РеэюмеИсследуются корреляции между пионами π−π+ и π−π−, рожденными в рр соударениях при 69 ГзВ/с. Отмечаются короткодействуюшие корреляции дляy1⋍y2; воэрастание обнаруживается вблиэиy1=y2=±1. Корреляции между поперечными переменными свяэаны с корреляциями для π−π− комбинаций, тогда как для π+π− укаэанный зффект является по сушеству кинематическим.