pp-elastic differential cross sections are reported at 492 MeV from 40° to 90°, and at 576, 642, 728, and 793 MeV from 75° to 90° c.m., with an absolute accuracy of less than 1%. These data, obtained with polyethylene targets, agree with recent measurements at the same energies obtained with a liquid-hydrogen target. © 1996 The American Physical Society.
No description provided.
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The absolute p-d elastic-scattering differential cross sections were measured at 641.3 and 792.7 MeV beam energies over a range of c.m. angles from ∼35° to ∼115° and ∼35° to ∼140°, respectively. The longitudinally polarized (L-type) proton beam produced by the Lamb-shift ion source at LAMPF was used. The beam intensity was measured to high accuracy (∼0.1%) by a scintillator-beam particle-counting system designed and developed prior to the experiment. Typical uncertainties in the absolute cross sections were about 2–3% total, somewhat larger at back angles. The present results were compared with the existing measurements and the controversy about the previous data at 800 MeV was resolved. The present data can be fit with a relativistic multiple-scattering theory which uses off-mass-shell extrapolations of the nucleon-nucleon amplitudes suggested by the structure of derivative meson-nucleon couplings. Relativistic-impulse-approximation calculations do not fit these data at either energy.
TARGET IS A LIQUID DEUTERIUM. THE LABORATORY ANGLES BIN SIZES ARE 30 MRAD AT FORWARD ANGLES AND 50 MRAD AT OTHER ANGLES.
TARGET IS A LIQUID DEUTERIUM. THE DATA IN THIS TABLE ARE THE SAME AS IN THE TABLE 1, BUT IN THE ANOTHER REPRESENTATION.
TARGET IS A LIQUID DEUTERIUM. THE DATA IN THIS TABLE ARE THE SAME AS IN THE TABLE 1, BUT IN THE ANOTHER REPRESENTATION.
Absolute pp-elastic-differential cross sections were measured at incident energies 492, 576, 642, 728, and 793 MeV from about 30° to 90° c.m. The total uncertainty was determined to be less than 1%, made possible by particle counting for beam normalization and extensive cross-checks of systematic effects. These new data are consistent with previous data above 600 MeV but have uncertainties about a factor of 10 smaller. Near 500 MeV these data are consistent with 90° data from TRIUMF, but differ significantly from similar data from PSI; the cause of this discrepancy is discussed.
No description provided.
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We have measured the spin-transfer parameters KLL, KSL, KLS, and KSS at 635 MeV from 50° to 178° c.m. and at 485 MeV from 74° to 176° c.m. These new data have a significant impact on the phase-shift analyses. There are now sufficient data near these energies to overdetermine the elastic nucleon-nucleon amplitudes.
Spin transfer parameters from np elastic scattering at 635 MeV. There is an additional overall normalisation of 2 PCT.
Spin transfer parameters from np elastic scattering at 485 MeV. There is an additional overall normalisation of 2 PCT.
The energy dependence of the pp elastic analyzing power has been measured using an internal target during polarized beam acceleration. The data were obtained in incident-energy steps varying from 4 to 17 MeV over an energy range from 0.5 to 2.0 GeV. The statistical uncertainty of the analyzing power is typically less than 0.01. A narrow structure is observed around 2.17 GeV in the two-proton invariant mass distribution. A possible explanation for the structure with narrow resonances is discussed.
Statistical errors only.
We employ data taken by the JADE and OPAL experiments for an integrated QCD study in hadronic e+e- annihilations at c.m.s. energies ranging from 35 GeV through 189 GeV. The study is based on jet-multiplicity related observables. The observables are obtained to high jet resolution scales with the JADE, Durham, Cambridge and cone jet finders, and compared with the predictions of various QCD and Monte Carlo models. The strong coupling strength, alpha_s, is determined at each energy by fits of O(alpha_s^2) calculations, as well as matched O(alpha_s^2) and NLLA predictions, to the data. Matching schemes are compared, and the dependence of the results on the choice of the renormalization scale is investigated. The combination of the results using matched predictions gives alpha_s(MZ)=0.1187+{0.0034}-{0.0019}. The strong coupling is also obtained, at lower precision, from O(alpha_s^2) fits of the c.m.s. energy evolution of some of the observables. A qualitative comparison is made between the data and a recent MLLA prediction for mean jet multiplicities.
Overall result for ALPHAS at the Z0 mass from the combination of the ln R-matching results from the observables evolved using a three-loop running expression. The errors shown are total errors and contain all the statistics and systematics.
Weighted mean for ALPHAS at the Z0 mass determined from the energy evolutions of the mean values of the 2-jet cross sections obtained with the JADE and DURHAMschemes and the 3-jet fraction for the JADE, DURHAM and CAMBRIDGE schemes evaluted at a fixed YCUT.. The errors shown are total errors and contain all the statistics and systematics.
Combined results for ALPHA_S from fits of matched predicitions. The first systematic (DSYS) error is the experimental systematic, the second DSYS error isthe hadronization systematic and the third is the QCD scale error. The values of ALPHAS evolved to the Z0 mass using a three-loop evolution are also given.
An experimental investigation of the structure of identified quark and gluon jets is presented. Observables related to both the global and internal structure of jets are measured; this allows for test
The measured jet broadening distributions (B) in quark and gluon jets seperately.
Measured distributions of -LN(Y2), where Y2 is the differential one-subjet rate, that is the value of the subjet scale parameter where 2 jets appear from the single jet.
The mean subjet multiplicity (-1) for gluon jets and quark jets for different values of the subject resolution parameter Y0.
The strong coupling constant, αs, has been determined in hadronic decays of theZ0 resonance, using measurements of seven observables relating to global event shapes, energy correlatio
Data corrected for finite acceptance and resolution of the detector and for intial state photon radiation. No corrections for hadronic effects are applied.. Errors include statistical and systematic uncertainties, added in quadrature.
Data corrected for finite acceptance and resolution of the detector and for intial state photon radiation. No corrections for hadronic effects are applied.. Errors include statistical and systematic uncertainties, added in quadrature.
Data corrected for finite acceptance and resolution of the detector and for intial state photon radiation. No corrections for hadronic effects are applied.. Errors include statistical and systematic uncertainties, added in quadrature.
A measurement of novel event shapes quantifying the isotropy of collider events is performed in 140 fb$^{-1}$ of proton-proton collisions with $\sqrt s=13$ TeV centre-of-mass energy recorded with the ATLAS detector at CERN's Large Hadron Collider. These event shapes are defined as the Wasserstein distance between collider events and isotropic reference geometries. This distance is evaluated by solving optimal transport problems, using the 'Energy-Mover's Distance'. Isotropic references with cylindrical and circular symmetries are studied, to probe the symmetries of interest at hadron colliders. The novel event-shape observables defined in this way are infrared- and collinear-safe, have improved dynamic range and have greater sensitivity to isotropic radiation patterns than other event shapes. The measured event-shape variables are corrected for detector effects, and presented in inclusive bins of jet multiplicity and the scalar sum of the two leading jets' transverse momenta. The measured distributions are provided as inputs to future Monte Carlo tuning campaigns and other studies probing fundamental properties of QCD and the production of hadronic final states up to the TeV-scale.
IRing2 for HT2>=500 GeV, NJets>=2
IRing2 for HT2>=500 GeV, NJets>=3
IRing2 for HT2>=500 GeV, NJets>=4
We present an angular analysis of the $B^{+}\rightarrow K^{\ast+}(\rightarrow K_{S}^{0}\pi^{+})\mu^{+}\mu^{-}$ decay using 9$\,\mbox{fb}^{-1}$ of $pp$ collision data collected with the LHCb experiment. For the first time, the full set of CP-averaged angular observables is measured in intervals of the dimuon invariant mass squared. Local deviations from Standard Model predictions are observed, similar to those in previous LHCb analyses of the isospin-partner $B^{0}\rightarrow K^{\ast0}\mu^{+}\mu^{-}$ decay. The global tension is dependent on which effective couplings are considered and on the choice of theory nuisance parameters.
Results for the CP-averaged observables Fl, Afb and S3–S9. The first uncertainties are statistical and the second systematic.
Results for the optimised observables FL and P1–P'8. The first uncertainties are statistical and the second systematic.
The CP-averaged observable Fl versus q2. The first (second) error bars represent the statistical (total) uncertainties.
Forum