A study of the reaction pp→p(nπ+) at the CERN intersecting storage rings
Description
New results are presented on the diffraction dissociation of protons into (nπ+) systems at the CERN intersecting storage rings. The data were taken at the centre of mass energy √s=45GeV and a very high statistics of events (nearly 75,000) was obtained. The experiment was performed at the Split Field Magnet whose description is made as well as that of the special neutron devices and of the trigger logic. The software chain (pattern recognition, geometrical reconstruction and kinematical fitting) is also described. A particular emphasis is put on the four-dimensional acceptance correction applied to the events. Phenomenological comments are given on two different but complementary approaches: the impact parameter description in the s-channel and the Deck model. The physics results are shown with in particular, detailed studies for the five following variables: the momentum transfer from proton to proton, the (nπ+) invariant mass, the Jackson angles of this system and the momentum transfer from proton to neutron. A comparison with the pion-exchange Deck model is performed, showing a qualitative agreement with the data. Several experiments at a lower energy are also compared: on the average, there is little evolution with energy
Abstract (French)
On presente de nouveaux resultats sur la diffraction dissociative dans la reaction pp→p(nπ+) aux anneaux de stockage a intersections du CERN. Les donnees ont ete prises a l'energie au centre de masse √s=45GeV et une tres grande statistique d'evenements (pres de 75000) a ete obtenue. L'experience a ete realisee a l'aimant a champ fractionne des I.S.R. (le S.F.M.) qui est decrit ainsi que les detecteurs speciaux a neutrons et la logique du declenchement. La chaine de programmes utilisee (recherche des traces, reconstruction geometrique et ajustement cinematique) est decrite en detail, la correction d'acceptance quadrimensionnelle est appliquee aux evenements. Dans l'etude phenomenologique sont presentees deux approches differentes mais complementaires: la description en parametre d'impact dans la voie et le modele de Deck. Les resultats de physique sont donnes avec, en particulier, des etudes detaillees dans les cinq variables suivantes: le transfert d'impulsion de proton a proton, la masse invariante de (nπ+), les angles de Jackson de ce systeme et le transfert d'impulsion de proton a neutron. Une comparaison avec le modele de Deck a echange de pion montre un accord qualitatif entre les donnees et le modele. Enfin plusieurs experiences realisees a plus basse energie sont comparees a celle-ci; cette comparaison permet de conclure qu'il y a, en moyenne, peu d'evolution avec l'energieAdditional details
Additional titles
- Original title (French)
- Etude de la reaction pp→p(nπ
Publishing Information
- Journal Title
- Ann. Phys. (Paris)
- Journal Volume
- 1
- Journal Issue
- 1
- Series
- Ann. Phys. (Paris).
- Journal Page Range
- 5-72
INIS
- Country of Publication
- France
- Country of Input or Organization
- France
- INIS RN
- 7277139
- Subject category
- S72: PHYSICS OF ELEMENTARY PARTICLES AND FIELDS;
- Descriptors DEI
- ANGULAR DISTRIBUTION; CENTER-OF-MASS SYSTEM; DATA PROCESSING; DECK EFFECT; DIFFERENTIAL CROSS SECTIONS; DIFFRACTION MODELS; ENERGY DEPENDENCE; GEV RANGE 10-100; IMPACT PARAMETER; MASS SPECTRA; MULTIWIRE PROPORTIONAL CHAMBER; NEUTRON DETECTION; NEUTRONS; PARTICLE PRODUCTION; PARTICLE TRACKS; PIONS PLUS; PROTON-PROTON INTERACTIONS; S CHANNEL; TOTAL CROSS SECTIONS
- Descriptors DEC
- BARYON-BARYON INTERACTIONS; BARYONS; BOSONS; CROSS SECTIONS; DISTRIBUTION; ELEMENTARY PARTICLES; ENERGY RANGE; FERMIONS; GEV RANGE; HADRON-HADRON INTERACTIONS; HADRONS; INTERACTIONS; MATHEMATICAL MODELS; MEASURING INSTRUMENTS; MESONS; NUCLEON-NUCLEON INTERACTIONS; NUCLEONS; PARTICLE INTERACTIONS; PARTICLE MODELS; PIONS; PROPORTIONAL COUNTERS; PSEUDOSCALAR MESONS; RADIATION DETECTION; RADIATION DETECTORS; SPECTRA