Precision Pion-Proton Elastic Differential Cross Sections at Energies Spanning the Delta Resonance

A precision measurement of absolute pi+p and pi-p elastic differential cross sections at incident pion laboratory kinetic energies from T_pi= 141.15 to 267.3 MeV is described. Data were obtained detecting the scattered pion and recoil proton in coincidence at 12 laboratory pion angles from 55 to 155 degrees for pi+p, and six angles from 60 to 155 degrees for pi-p. Single arm measurements were also obtained for pi+p energies up to 218.1 MeV, with the scattered pi+ detected at six angles from 20 to 70 degrees. A flat-walled, super-cooled liquid hydrogen target as well as solid CH2 targets were used. The data are characterized by small uncertainties, ~1-2% statistical and ~1-1.5% normalization. The reliability of the cross section results was ensured by carrying out the measurements under a variety of experimental conditions to identify and quantify the sources of instrumental uncertainty. Our lowest and highest energy data are consistent with overlapping results from TRIUMF and LAMPF. In general, the Virginia Polytechnic Institute SM95 partial wave analysis solution describes our data well, but the older Karlsruhe-Helsinki PWA solution KH80 does not.Comment: 39 pages, 22 figures (some with quality reduced to satisfy ArXiv requirements. Contact M.M. Pavan for originals). Submitted to Physical Review

The CHAOS spectrometer for pion physics at TRIUMF

The Canadian high acceptance orbit spectrometer (CHAOS) is a unique magnetic spectrometer system recently commissioned for studies of pion induced reactions at TRIUMF. It is based on a cylindrical dipole magnet producing vertical magnetic fields up to 1.6 T. The scattering target is located in the center of the magnet. Charged particle tracks produced by pion interactions there are identified using four concentric cylindrical wire chambers surrounding the target. Particle identification and track multiplicity are determined by cylindrical layers of scintillation counters and lead-glass Cherenkov counters, which also provide a first level trigger. A sophisticated second level trigger system permits pion fluxes in excess of 5 MHz to be employed. The detector subtends 360\ub0 in the horizontal plane, and \ub17\ub0 out of this plane for a solid angle coverage approximately 10% of 4\u3c0 sr. The momentum resolution delivered by the detector system is 1% (\u3c3)

The T2K experiment

The T2K experiment is a long baseline neutrino oscillation experiment. Its main goal is to measure the last unknown lepton sector mixing angle θ13 by observing νe appearance in a νμ beam. It also aims to make a precision measurement of the known oscillation parameters, and sin22θ23, via νμ disappearance studies. Other goals of the experiment include various neutrino cross-section measurements and sterile neutrino searches. The experiment uses an intense proton beam generated by the J-PARC accelerator in Tokai, Japan, and is composed of a neutrino beamline, a near detector complex (ND280), and a far detector (Super-Kamiokande) located 295 km away from J-PARC. This paper provides a comprehensive review of the instrumentation aspect of the T2K experiment and a summary of the vital information for each subsystem

ANALYZING POWER MEASUREMENTS IN πd ELASTIC SCATTERING AT 50 MeV

Nos mesures du pouvoir d'analyse vectoriel dans la diffusion élastique πd à 50 MeV sont en accord avec les prédictions des modèles qui incluent la partie P11 du potentiel πN intégral mais sont en désaccord avec ceux qui omettent ou suppriment cette composante.Measurements of the vector analyzing power in πd elastic scattering at 50 MeV are found to agree well with model calculations that include the full πN P11 potential and disagree when this is omitted or suppressed

Analyzing powers for pi+- p polarized elastic scattering between 87-MeV and 263-MeV

Analyzing powers for \u3c0p elastic scattering were measured using the CHAOS spectrometer at energies spanning the \u394(1232) resonance. This work presents \u3c0+ data at the pion kinetic energies 117, 130, 139, 155, 169, 180, 193, 218, 241, and 267 MeV and \u3c0- data at 87, 117, 193, and 241 MeV, covering an angular range of 50\ub0<~\u3b8c.m.<~180\ub0 at the higher energies and 90\ub0<~\u3b8c.m.<~180\ub0 at the lower energies. Unique features of the spectrometer acceptance were employed to reduce systematic errors. Single-energy phase shift analyses indicate the resulting S11 and S31 phases favor the results of the SM95 phase shift analysis over that of the older KH80 analysis