Program hadronske spektroskopije sustavom COMPASS

Abstract

(for the COMPASS Collaboration) COMPASS is a fixed-target experiment at the CERN SPS for the investigation of the structure and dynamics of hadrons. The experimental setup features a large acceptance and high momentum resolution spectrometer including particle identification and calorimetry and is therefore ideal to access a broad range of different final states. Following the promising observation of a spin-exotic resonance during an earlier pilot run, COMPASS focused on light-quark hadron spectroscopy during the years 2008 and 2009. A data set, world leading in terms of statistics and resolution, has been collected with a 190 GeV/c hadron beam impinging on either liquid hydrogen or nuclear targets. Spin-exotic meson and glueball candidates formed in both diffractive dissociation and central production are presently studied. Since the beam composition includes protons, the excited baryon spectrum is also accessible. Furthermore, Primakoff reactions have the potential to determine radiative widths of the resonances and to probe chiral perturbation theory. An overview of the ongoing analyses will be presented. In particular, the employed partial-wave analysis techniques will be illustrated and recent results will be shown for a selection of final states.COMPASS je mjerni sustav s mirnom metom za istraživanje građe i dinamike hadrona pri ubrzivaču SPS u CERNu. Taj sustav odlikuje spektrometar visokog impulsnog razlučivanja s velikim zahvaćanjem, mjerenjem energije i prepoznavanjem čestica, pa je posebno pogodan za opažanje u širokom području različitih konačnih stanja. Nakon ohrabrujućih opažanja rezonancije s egzotičnim spinom tijekom ranijih probnih mjerenja, u 2008. i 2009. su mjerenja s COMPASSom bila usmjerena na hadronsku spektroskopiju lakih kvarkova. S hadronskim snopom 190 GeV/c na meti vodika ili atomskih jezgara postignuti su najbolji svjetski ishodi u pogledu statistike i razlučivanja. U tijeku su proučavanja mezona s egzotičnim spinom i gluonske lopte koji su dobiveni difraktivnim razdvajanjem odnosno središnjim sudarima. Kako snop sadrži također protone, dobivaju se također barioni u uzbudnom stanju. Nadalje, Primakoffove reakcije pružaju određivanja radijativnih širina rezonancija i ispitivanja kiralne teorije smetnje. U radu se opisuju analize u tijeku. Posebice se predstavljaju primijenjene tehnike analize parcijalnim valovima i prikazuju ishodi za niz odabranih konačnih stanja

    Similar works