A partial-wave analysis of the (3 π ) 0 system produced peripherally in the reaction K − p → π + π − π 0 Λ at 4.2 GeV/ c is presented. The observation of the weak Λ decay allows a determination of all the transversity production amplitudes except for two phases. The production of known resonances having decay modes other than 3 π is used to test the isobar model ansatz. Significant ω(783), φ(1020) and A 2 (1310) production is observed. The spin parity of the ω ∗ (1675) is established as 3 − . No evidence for production of other resonances, such as axial vector-mesons, is found.
No description provided.
A partial-wave analysis of the low-mass ( π + π − p) system produced in the reaction K − p → K − ( π + π − p) at 4.2 GeV/ c incident momentum is performed in order to study the two ( π + π − p) enhancements around 1500 and 1700 MeV. It is found that the low-mass ( π + π − p) system can be described using the spin-parity states J P = 1 2 + , 3 2 − and 5 2 + only. In the 1500 MeV region contributions are observed from the 1 2 + wave decaying into pϵ and the 3 2 − wave decaying into Δ ++ π − ; in the 1700 MeV region contributions are found from the 1 2 + wave decaying into Δ ++ π − , the 3 2 − wave decaying into pϵ, and the 5 2 + wave decaying into pϵ.
No description provided.
A partial wave analysis of the K 0 π + π − system produced in the charge exchange reaction K − p → ( K 0 π + π − ) n at 4.2 GeV/ c has been performed both as a function of Kππ mass and of t ′. The 1 + S wave forms the largest contribution to the K ππ system and peaks at roughly the same mass as the Q in diffractive K ππ production. The polarization properties of the 1 + S ( K ∗ π) and 1 + S (Kϱ) waves differ fromt those of the diffractive 1 + wave. There is some evidence for a resonance contribution to 1 + S ( K ∗ π) . The strong 2 + wave the K ∗ (1420) and the K ϱ/ K ∗ ϱ decay branching ratio determined to be 0.36±0.10. An enhancement with spin-parity 1 − is observed under K ∗ (1420) .
CROSS SECTION CORRECTED FOR BREIT-WIGNER TAILS, THE TP CUT, UNSEEN <AK0 PI> AND <K RHO> DECAY MODES. BRANCHING RATIO K*(1420) --> <K RHO>/<K* PI> = 0.36 +- 0.10.
No description provided.
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.
The analyzing power,$A_{oono}$, and the polarization transfer observables$K_{onno}$,$K_{os''so}$
Position 'A' (see text for explanation).
Position 'A' (see text for explanation).
Position 'A' (see text for explanation).
We have measured the absolute cross section σ(θ) and complete sets of spin observables A00ij in He3(p,p) elastic scattering at energies of 200 and 500 MeV. The observables depend on linear combinations of six complex scattering amplitudes for the p−3He system and provide a severe test of current reaction models. The in-scattering plane observables (A00mm, A00ll, A00lm, and A00ml) are all in quantitative disagreement with fully microscopic nonrelativistic optical model calculations and nonrelativistic distorted wave Born approximation calculations.
A00N0 is analyzing power.
A00N0 is analyzing power.
A00NN is spin correlation parameter.
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 polarized proton beam extracted from SATURNE II and the Saclay polarized proton target were used to measure the rescattering observables$K_{onno}$and
No description provided.
No description provided.
No description provided.
The three polarization tensor components of the deuteron produced in the H( p , d )π + reaction have been measured for the first time. The experiment was performed using a vertically polarized proton beam produced by the SATURNE accelerator. The deuteron polarization was measured with the POLDER polarimeter. The three polarizing powers t 20 00 , t 21 00 and t 22 00 and the three spin-transfer observables t 20 11 , t 22 11 and t 22 11 have been extracted at a proton kinetic energy of 580 MeV over a wide angular range and at two fixed center-of-mass angles, 132° and 151°, between 800 and 1300 MeV. The six observables, calculated in the C.M. helicity frame, have been compared with predictions of the most refined partial-wave analyses and also with the predictions of a theoretical coupled-channel model which includes the NN-NΔ transition. The comparison between the data and the theory/partial-wave analyses shows some discrepancies which get worse with increasing proton energy. Adding these data to the world database should improve significantly future partial-wave analyses. The A y 0 analyzing power has also been measured over the same kinematical range. The partial-wave analysis predictions are in good agreement with this observable.
No description provided.
No description provided.
No description provided.
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
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.
Decay correlation data for π − p → K ∗ Λ at 3.9 GeV /c are analyzed to determine the amplitude structure. We emphasize combinations of observables invariant under rotations between s and t channel frames.
No description provided.
Polarization transfer observables in π + d elastic scattering have been measured for the first time. Four polarization transfer parameters were determined at pion energies T π =134 MeV and 180 MeV at scattering angles θ π ,C.M. between 100° and 140° using a deuteron target polarized perpendicular to the scattering plane and a deuteron tensor polarimeter. The data are compared to different predictions from the SAID phase shift analysis and Faddeev calculations.
Systematic and statistical errors are added in quadrature.
Systematic and statistical errors are added in quadrature.
A double scattering experiment, performed at the Paul-Scherrer-Institut (PSI), has measured a large variety of spin observables for free np elastic scattering from 260 to 535 MeV in the c.m. angle ran
Measurements of DNN with statistical errors only.
Measurements of DSL with statistical errors only.
Measurements of DSS with statistical errors only.
We report measurements of spin correlations and analyzing powers in He→3(p→, 2p) and He→3(p→, pn) quasielastic scattering as a function of momentum transfer and missing momentum at 197 MeV using a polarized internal target at the Indiana University Cyclotron Facility Cooler Ring. At sufficiently high momentum transfer we find He→3(p→, pn) spin observables are in good agreement with free p−n scattering observables, and therefore that He→3 can serve as a good polarized neutron target. The extracted polarizations of nucleons in He→3 at low missing momentum are consistent with Faddeev calculations.
QUASIELASTIC SCATTERING.
The reaction π − p↑→ π − π + π − p has been measured at 17 GeV/ c using a polarized target. The data sample contains about 60 000 interactions on polarized protons. The nucleon polarization as a function of momentum transfer is very similar to elastic π − p scattering and is nearly independent of the π mass, except for a possible structure around 1.2 GeV.
No description provided.
The reaction π − p→ π + π − n has been measured in a high-statistics experiment on a transversely polarized proton target at 17.2 GeV, and unexpectedly large nucleon polarization effects have been observed. Combining the results of this experiment with a measurement on a hydrogen target allows a model-independent partial-wave analysis in terms of the “nucleon transversity” amplitudes. Unique or at most twofold ambiguous solutions are obtained. In particular we find a high lower limit ( ⪆30% ) of the spin non-flip unnatural exchange amplitudes at low | t |. These amplitudes, interpreted as being due to the exchange of an object with the quantum numbers of the A 1 , have been assumed to be absent in previous analyses. In checking the consequences of this finding on the old results, we test the validity of the rank-two assumotions for the density matrix. We find a small but significant deviation, which shows the need for a new phase-shift analysis including the A 1 exchange contribution.
MASS DEPENDENCE OF NORMALIZED T-CHANNEL MOMENTS SCALED TO 100 PCT POLARIZED PROTONS.
T DEPENDENCE OF NORMALIZED T-CHANNEL MOMENTS IN THE RHO REGION SCALED TO 100 PCT POLARIZED PROTONS.
We present single inclusive π±, π0 andK± spectra in the forward fragmentation region (x>0.2,pT<1.5 GeV/c) as well as correlations between two charged particles. The data were recorded in an unseparated negative hadron beam at the CERN SPS using a large acceptance forward spectrometer. Our maasurements are compared in detail with several models which emphasise the role of the beam valence quarks in this production process. The connection to measurements at largepT is also investigated.
ERRORS INCLUDE SYSTEMATIC ERRORS BUT NOT OVERALL NORMALISATION UNCERTAINTY OF 8PCT.
ERRORS INCLUDE SYSTEMATIC ERRORS BUT NOT OVERALL NORMALISATION UNCERTAINTY OF 8PCT.
ERRORS INCLUDE SYSTEMATIC ERRORS BUT NOT OVERALL NORMALISATION UNCERTAINTY OF 8PCT.
Measurements are presented for several mixtures of the spin observables CSS,CSL=CLS, CLL, and CNN for neutron-proton elastic scattering. These data were obtained with a free polarized neutron beam, a polarized proton target, and a large magnetic spectrometer for the outgoing proton. The neutron beam kinetic energies were 484, 567, 634, 720, and 788 MeV. Combining these results with earlier measurements allows the determination of the pure spin observables CSS, CLS, and CLL at 484, 634, and 788 MeV for c.m. angles 25°≤θc.m.≤180° and at 720 MeV for 35°≤θc.m.≤80°. These data make a significant contribution to the knowledge of the isospin-0 nucleon-nucleon scattering amplitudes. © 1996 The American Physical Society.
Results for the pure spin observables. Statistical errors only. (Data for CSS and CNN at (172.5 to 177.5) and (167.5 to 172.5) degrees are uncertain because of the rapid angular dependence and possible errors in angle, and may be omitted from phase shift analyses.) The CNN data without errors are from a phase shift analysis of Arndt et al. (PR D45 (1992) 3395) [FA92] and were used to derive pure spin observables from the measured data.
Results for the pure spin observables. Statistical errors only. (Data for CSS and CNN at (172.5 to 177.5) and (167.5 to 172.5) degrees are uncertain because of the rapid angular dependence and possible errors in angle, and may be omitted from phase shift analyses.) The CNN data without errors are from a phase shift analysis of Arndt et al. (PR D45 (1992) 3395) [FA92] and were used to derive pure spin observables from the measured data.
Results for the pure spin observables. Statistical errors only. The CNN data without errors are from a phase shift analysis of Arndt et al. (PR D45 (1992) 3395) [FA92] and were used to derive pure spin observables from the measured data.
A measurement of jet substructure observables is presented using \ttbar events in the lepton+jets channel from proton-proton collisions at $\sqrt{s}=$ 13 TeV recorded by the CMS experiment at the LHC, corresponding to an integrated luminosity of 35.9 fb$^{-1}$. Multiple jet substructure observables are measured for jets identified as bottom, light-quark, and gluon jets, as well as for inclusive jets (no flavor information). The results are unfolded to the particle level and compared to next-to-leading-order predictions from POWHEG interfaced with the parton shower generators PYTHIA 8 and HERWIG 7, as well as from SHERPA 2 and DIRE2. A value of the strong coupling at the Z boson mass, $\alpha_S(m_\mathrm{Z}) = $ 0.115$^{+0.015}_{-0.013}$, is extracted from the substructure data at leading-order plus leading-log accuracy.
Distribution of $\lambda_{0}^{0}$ (N) reconstructed from charged particles with pt > 1 GeV, unfolded to the particle level.
Distribution of $\lambda_{0}^{0}$ (N) reconstructed from charged particles with pt > 1 GeV, unfolded to the particle level.
Distribution of $\lambda_{0}^{2}$ ($p_{T}^{d,*})$ reconstructed from charged particles with pt > 1 GeV, unfolded to the particle level.
After summarizing the properties of the socalled Dalitz Array (DA), which is a genuine characteristics of a resonance, we determine those of the well known ε, γ, andA2 resonances produced in theK−p→π+π−π0Λ final state at 4.2 Ge V/c. A tentative measurement of the DA of theA1 meson produced backwards in the reactionK−p→π+π+π−Σ− is also presented. The data for this analysis come from the high statistics (130 events/μb) experiment performed by the ACNO Collaboration.
FROM FITTING MOMENTS OF DALITZ SERIES WITH BREIT-WIGNER RESONANCE PLUS BACKGROUND. FOR -T < 1.0 GEV**2, CROSS SECTION IS 14 +- 2.5 MUB.
BACKWARD CROSS SECTION USING DALITZ SERIES.
p p annihilations, leading to the production of at least one neutral K meson in the final state, have been studied in the incident momentum region of 700–760 MeV/ c . Topological cross sections and cross sections for the various exclusive final states are presented. Detailed analyses of the different final states have been carried out to study the importance of resonance production and of quasi two-body and quasi three-body processes. A detailed study of the K K π system in the four-body final states shows that the F 1 meson is a spurious effect due to systematic biases. In the momentum range investigated, the C = +1 final states are strongly suppressed.
SUMMARY OF QUASI-TWO-BODY CROSS SECTIONS.
No description provided.
No description provided.
The target asymmetry T, recoil asymmetry P, and beam-target double polarization observable H were determined in exclusive $\pi ^0$ and $\eta $ photoproduction off quasi-free protons and, for the first time, off quasi-free neutrons. The experiment was performed at the electron stretcher accelerator ELSA in Bonn, Germany, with the Crystal Barrel/TAPS detector setup, using a linearly polarized photon beam and a transversely polarized deuterated butanol target. Effects from the Fermi motion of the nucleons within deuterium were removed by a full kinematic reconstruction of the final state invariant mass. A comparison of the data obtained on the proton and on the neutron provides new insight into the isospin structure of the electromagnetic excitation of the nucleon. Earlier measurements of polarization observables in the $\gamma p \rightarrow \pi ^0 p$ and $\gamma p \rightarrow \eta p$ reactions are confirmed. The data obtained on the neutron are of particular relevance for clarifying the origin of the narrow structure in the $\eta n$ system at $W = 1.68\ \textrm{GeV}$. A comparison with recent partial wave analyses favors the interpretation of this structure as arising from interference of the $S_{11}(1535)$ and $S_{11}(1650)$ resonances within the $S_{11}$-partial wave.
Target asymmetry T, recoil asymmetry P, and polarization observable H for $\gamma p \to \pi^0 p$ as a function of the polar center-of-mass angle for bins at the given centroid c.m. energies.
Target asymmetry T, recoil asymmetry P, and polarization observable H for $\gamma n \to \pi^0 n$ as a function of the polar center-of-mass angle for bins at the given centroid c.m. energies.
Target asymmetry T, recoil asymmetry P, and polarization observable H for $\gamma p \to \eta p$ as a function of the polar center-of-mass angle for bins at the given centroid c.m. energies.
We present data of several rescattering observables measured inn p elastic scattering between 0.80 and 1.10 GeV. The SATURNE II polarized beam of free neutrons obtained from the break-up of polarized deuterons was scattered on the Saclay polarized frozen-spin proton target. Three different configurations of beam and target polarization directions were used: the observablesDonon andKonno were measured with the normal-normal spin configuration at eight energies;Nonkk,Dos″ok andKos″ko were determined with the longitudinal-longitudinal configuration at six energies;Nonsk,Dos″ok andKos″so with the sideway-longitudinal configuration at six energies. Part of the data was obtained with an unpolarized CH2 target where only the two spin-index polarization transfer parametersKos″ko andKos″so were determined. Data are compared with phase shift analyses predictions and with the LAMPF results at 0.788 GeV. Present results are the first measurements of rescattering observables above 0.80 GeV. They provide an important contribution to any future theoretical or phenomenological analysis.
No description provided.
No description provided.
No description provided.
We present a measurement of angular observables, $P_4'$, $P_5'$, $P_6'$, $P_8'$, in the decay $B^0 \to K^\ast(892)^0 \ell^+ \ell^-$, where $\ell^+\ell^-$ is either $e^+e^-$ or $\mu^+\mu^-$. The analysis is performed on a data sample corresponding to an integrated luminosity of $711~\mathrm{fb}^{-1}$ containing $772\times 10^{6}$ $B\bar B$ pairs, collected at the $\Upsilon(4S)$ resonance with the Belle detector at the asymmetric-energy $e^+e^-$ collider KEKB. Four angular observables, $P_{4,5,6,8}'$ are extracted in five bins of the invariant mass squared of the lepton system, $q^2$. We compare our results for $P_{4,5,6,8}'$ with Standard Model predictions including the $q^2$ region in which the LHCb collaboration reported the so-called $P_5'$ anomaly.
Results of the angular analysis of $B^0 \to K^\ast(892)^0 \ell^+ \ell^-$ (where $\ell = e,\mu$) in five bins of $q^2$, the di-lepton invariant mass squared.
Forum