We present measurements of the αα elastic scattering differential cross section at √ s = 126 GeV in the range 0.05 ⩽ ‖ t ‖
ERRORS ARE STATISTICAL ONLY.
EXPONENTIAL FIT TO CROSS SECTION BELOW T = 0.075 GEV**2.
OPTICAL THEOREM CALCULATION OF THE TOTAL CROSS SECTION ASSUMING RHO IS ZERO.
We have measured the differential cross section for pp and p̄p elastic scattering at √ s = 31, 53 and 62 GeV in the interval 0.05 < | t | < 0.85 GeV 2 at the CERN ISR using the Split Field Magnet detector. At 53 and 62 GeV, for 0.17 < | t | < 0.85 GeV 2 both pp and p̄p data show simple exponential behaviour in t ; at √ s = 31 GeV the data for 0.05 < | t | < 0.85 GeV 2 are consistent with a change in slope near | t | = 0.15 GeV 2 .
ERRORS CONTAIN BOTH STATISTICAL AND T-DEPENDENT SYSYEMATIC ERRORS.
No description provided.
LOCAL SLOPE PARAMETERS BASED ON QUADRATIC EXPONENTIAL FIT.
We have measured the inclusive cross-section as a function of missing energy, due to the production of neutrinos or new weakly interacting neutral particles in 450 GeV/c proton-nucleus collisions, using calorimetric measurements of visible event energy. Upper limits are placed on the production of new particles as a function of their energy. These upper limits are typically an order
Differential single diffraction cross section.
Differential single diffraction cross section.
Differential single diffraction cross section.
Deeply virtual Compton scattering has been measured in e^+p collisions at HERA with the ZEUS detector using an integrated luminosity of 61.1 pb^-1. Cross sections are presented as a function of the photon virtuality, Q^2, and photon-proton centre-of-mass energy, W, for a wide region of the phase space, Q^2>~1.5 GeV^2 and 40<W<170 GeV. A subsample of events in which the scattered proton is measured in the leading proton spectrometer, corresponding to an integrated luminosity of 31.3 pb^-1, is used for the first direct measurement of the differential cross section as a function of t, where t is the square of the four-momentum transfer at the proton vertex.
The DVCS cross section as a function of Q**2.
The DVCS cross section as a function of W.
The DVCS cross section as a function of W in four Q**2 regions.
A study has been made of pseudoscalar mesons produced centrally in pp interactions. The results show that the eta and etaprime appear to have a similar production mechanism which differs from that of the pi0. The production properties of the eta and etaprime are not consistent with what is expected from double Pomeron exchange. In addition the production mechanism for the eta and etaprime is such that the production cross section are greatest when the azimuthal angle between the pT vectors of the two protons is 90 degrees.
No description provided.
Resonance production as a function of dPT - the difference in the transverse momentum vectors of the two exchange particles, expressed as a percentage of its total contribution.
T distributions have been fitted to the form D(SIG)/D(T) = const(NAME=ALPHA)*EXP(-SLOPE(C=1)*T) + const(NAME=BETA)*T**2*EXP(-SLOPE(C=2)*T).
Deep inelastic electron-photon scattering is studied in the Q2 ranges from 6 to 30 GeV2 and from 60 to 400 GeV2 using the full sample of LEP data taken with the OPAL detector at centre-of-mass energies close to the Z0 mass, with an integrated luminosity of 156.4 pb−1. Energy flow distributions and other properties of the measured hadronic final state are compared with the predictions of Monte Carlo models, including HERWIG and PYTHIA. Sizeable differences are found between the data and the models, especially at low values of the scaling variable x. New measurements are presented of the photon structure function $F_2^{αmma }(x,Q^2)$, allowing for the first time for uncertainties in the description of the final state by different Monte Carlo models. The differences between the data and the models contribute significantly to the systematic errors on $F_2^{αmma }$. The slope ${⤪ d}(F_2^{αmma }/←pha )/{⤪ d ln} Q^2$ is measured to be $0.13_{-0.04}^{+0.06}$.
No description provided.
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THE AZIMUTHAL ANGLE DISTRIBUTIONS OF PI0 HAVE BEEN FITTED BY: D(N)/D(PHI)=N*(1+CONST(Q=1)*COS(PHI)+CONST(Q=2)*COS(2*PHI)), WHERE PHI IS THE AZIMUTHAL ANGLEOF PI0 RELATIVE TO THE FOLLOWING COORDINATE SYSTEM: Z AXIS DIRECTED ALONG BEAM MOMENTUM, X AXIS DIRECTED ALONG TRANSVERSE MOMENTUM CONSTRUCTED FROM TRANSVERSE MOMENTA OF THE FINAL STATE PARTICLES (SEE PAPER). THE 17 PCT OF ALL NONPERIPHERAL EVENTS HAS BEEN REMOVED (SEE PAPER).
THE AZIMUTHAL ANGLE DISTRIBUTIONS OF CHARGED PARTICLES HAVE BEEN FITTED BY : D(N)/D(PHI)=N *(1+CONST(Q=1)*COS(PHI)+CONST(Q=2)*COS(2*PHI)), WHERE PHI IS THEAZIMUTHAL ANGLE OF CHARGED PARTICLE RELATIVE TO THE FOLLOWING COORDINATE SYSTEM : Z AXIS DIRECTED ALONG BEAM MOMENTUM, X AXIS DIRECTED ALONG TRANSVERSE MOMENTU M CONSTRUCTED FROM TRANSVERSE MOMENTA OF THE FINAL STATE PARTICLES (SEE PAPER). A systematic error of 0.03 has been estimated for CONST(Q=1) and CONST(Q= 2).
THE AZIMUTHAL ANGLE DISTRIBUTIONS OF NEUTRONS HAVE BEEN FITTED BY: D(N)/D (PHI)=N *(1+CONST(Q=1)*COS(PHI)+CONST(Q=2)*COS(2*PHI)), WHERE PHI IS THE AZIMUTHAL ANGLE OF NEUTRON RELATIVE TO THE FOLLOWING COORDINATE SYSTEM: Z AXIS DIRECTEDALONG BEAM MOMENTUM, X AXIS DIRECTED ALONG TRANSVERSE MOMENTUM CONSTRUCTED FRO M TRANSVERSE MOMENTA OF THE FINAL STATE PARTICLES (SEE PAPER). A systematic error of 0.03 has been estimated for CONST(Q=1) and CONST(Q= 2).
Momenta of charged particles produced in inelastic αα, αp, andpp collisions were measured using the Split-Field-Magnet detector at the CERN Intersecting Storage Rings. Inclusive and semi-in-clusive spectra are presented as a function of rapidityy, Feynman-x, and transverse momentumpT. The inclusivey distributions agree well with predictions of the dual parton model; the highest particle densities are reached aty≃0 and the momenta of leading protons decrease significantly for increasing total multiplicity. ‘Temperatures’ are equal in αα, αp, andpp interactions. ThepT distributions depend weakly on the multiplicity.
No description provided.
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Single particle distributions of π ± , K ± , p , p and d near mid-rapidity from 450 GeV/c p A and 200 GeV/c per nucleon SA collisions are presented. Inverse slope parameters are extracted from the transverse mass spectra, and examined for indications of collective phenomena. Proton and antiproton yields are determined for different projectile-target combinations. First results from 160 GeV/c per nucleon PbPb collisions are presented.
No description provided.
PRELIMINARY DATA FOR CENTRAL EVENTS.
Charged particle production in central S-S collisions at 200 GeV/ c per nucleon has been studied by the WA94 experiment at the CERN-SPS. Particle identification has been provided by the Omega RICH, while a silicon telescope in the Omega spectrometer and an array of MultiWire Proportional Chambers have been used to trace particles through the RICH detector. Production ratios and transverse mass spectra for π ± , K ± and p( p ) at central rapidity and p T > 1.3 GeV/ c are presented.
Distributions are fitted with (1/MT**1.5)*DSIG/DMT = CONST*EXP(-MT/SLOPE).
1.54 GeV ratio is calculated from the fit to the MT distribution.
1.54 GeV ratio is calculated from the fit to the MT distribution.
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