The Mark II detector at SPEAR has been used to study D-meson production in e+e− annihilation at center-of-mass energies between 3.8 and 6.7 GeV. The neutral and charged D mesons are identified from their K∓π± and K∓π±π± decay modes. Measurements of RD and of the inclusive differential cross section s dσdz are presented. The quasi-two-body cross sections σDD¯, σD*D¯, and σD*D¯* are derived from an overall fit to the D recoil spectra. No evidence was found for the associated production of charmed mesons and charmed baryons.
No description provided.
No description provided.
EXCLUSIVE D AD PRODUCTION CROSS SECTIONS FROM THE RECOIL SPECTRA FITS. METHOD 1 ASSUMES AN ISOTROPIC ANGULAR DISTRIBUTION OF THE D RELATIVE TO THE PARENT D* DIRECTION OF MOTION. METHOD 2 ASSUMES THE ANGULAR DISTRIBUTION IS 1 + A COS(THETA)**2.
None
No description provided.
Only statistical errors are given.
We have searched for resonance production in the reaction γγ→Ks0Kπ. No signal was found for theηc and an upper limit for the radiative with\(\Gamma _{\gamma \gamma }^{\eta _c } \) keV (95% c.l.) is obtained. For the glueball candidate η(1440) (previouslyi) the upper limit\(\Gamma _{\gamma \gamma }^{\eta (1440)} B(\eta (1440) \to K\bar K\pi )< 1.2keV(95\% c.l.)\) is derived. In the tagged data sample resonance formation of a spin 1 state at 1420 MeV is observed, which is absent in the untagged data. The mass and width of this state are consistent with those of thef1(1420); an analysis of decay angular distributions favours positive parity.
Data read from graph.. Additional overall systematic error decreasing from 25% in the lowest mass bins to 15% for M > 2.0 GeV.
Using a data sample with a total integrated luminosity of 10.0 pb$^{-1}$ collected at center-of-mass energies of 2.6, 3.07 and 3.65 GeV with BESII, cross sections for $e^+e^-$ annihilation into hadronic final states ($R$ values) are measured with statistical errors that are smaller than 1%, and systematic errors that are about 3.5%. The running strong interaction coupling constants $\alpha_s^{(3)}(s)$ and $\alpha_s^{(5)}(M_Z^2)$ are determined from the $R$ values.
R values.
Reactions involving Λ and Σ 0 production are studied in 7.3 GeV/ c K + p interactions. Cross sections and angular distributions are given.
Axis error includes +- 0.0/0.0 contribution (?////Corrected for detection and scanning losses and LAMBDAbar neutral decay modes).
The backward angular distributions obtained in an experiment at the Zero Gradient Synchrotron of Argonne National Laboratory were used to systematically study the energy dependence of the 180° differential cross section for π+p elastic scattering in the center-of-mass energy region from 2159 to 3487 MeV. At each of 38 incident pion momenta between 2.0 and 6.0 GeV/c, a focusing spectrometer and scintillation counter hodoscopes were used to obtain differential cross sections for typically five pion scattering angles from 141° to 173° in the laboratory. Values for dσdΩ at 180° were then obtained by extrapolation. A resonance model and an interference model were used to perform fits to the energy dependence of dσdΩ (180°). Both models led to good fits to our data and yielded values for the masses, widths, parities, and the product of spin and elasticity for the Δ(2200), Δ(2420), Δ(2850), and Δ(3230) resonances. Our data confirm the existence of the Δ(3230) and require the negative-parity Δ(2200).
No description provided.
No description provided.
No description provided.
The reaction γ+p→π++n has been investigated for photon energies between 1.2 and 3 GeV and pion c.m. angles from 2.5 to 15°. The cross section is strongly peaked in the forward direction and shows resonance structure in the region of the N32*(1920) and N12*(2190).
No description provided.
No description provided.
No description provided.
Differential cross sections for the reaction $\gamma p \to n \pi^+$ have been measured with the CEBAF Large Acceptance Spectrometer (CLAS) and a tagged photon beam with energies from 0.725 to 2.875 GeV. Where available, the results obtained here compare well with previously published results for the reaction. Agreement with the SAID and MAID analyses is found below 1 GeV. The present set of cross sections has been incorporated into the SAID database, and exploratory fits have been made up to 2.7 GeV. Resonance couplings have been extracted and compared to previous determinations. With the addition of these cross sections to the world data set, significant changes have occurred in the high-energy behavior of the SAID cross-section predictions and amplitudes.
Differential cross sections for incident photon energies 0.725, 0.775, 0.825and 0.875 GeV.
Differential cross sections for incident photon energies 0.925, 0.975, 1.025and 1.075 GeV.
Differential cross sections for incident photon energies 1.125, 1.175, 1.225and 1.275 GeV.
Pairs of τ leptons produced at s=3.77 GeV have been studied in eμ, ee, and μμ final states. The leptonic branching ratios have been measured to be B(τ→eνν)=(18.2±0.7±0.5)% and B(τ→μνν)=(18.0±1.0±0.6)%. Limits have been set for the two-body decays τ→eG and τ→μG, where G is a light Goldstone boson.
No description provided.
No description provided.
No description provided.
The e + e − → p p cross section has been measured in the energy interval (1975 ⩽ 2 E ⩽ 2250) MeV for |cos θ | < 0.7. The measurement is based on ∼ 100 events, thus improving by a factor 3 on the previous existing statistics in this energy interval. The form factor | G | 2 is given as a function of energy under the assumption | G E | = | G M |. We also give the first measurement of the differential cross section, averaged over the energy interval, and estimate the ratio G M |/| G E | from it.
No description provided.
No description provided.
No description provided.
A comparison is made of the properties and production mechanisms of the π + ω and K − ω systems produced in the reactions π + p → π + ω p at 4, 5, 8 and 16 GeV/ c and K − p → K − ω p at 10 and 16 GeV/ c . In the π + ω case apeak is observed at 1.23 GeV (the B meson), while the K − ω mass distribution has a threshold enhancement. The cross section of the low mass (<2.0 GeV) π + ω system falls as p lab −2 , while that of the low mass (<2.0 GeV) K − ω system is almost constant with energy, indicating diffractive production of the K − ω system, but not of the πω system. Using a modified version of the Illinois partial-wave analysis program, it is found that the K − ω system is dominantly produced in the J P = 1 + state with small contributions of 0 − and 2 + , mainly by natural parity exchange - as is found for reactions such as K − p → (K − π + π − )p which are predominantly diffractive. For the π + ω system in the B mass region, J P = 1 + states, produced mainly by natural parity exchange are found; the contributions of 0 − P, 1 − P, 2 − P and 2 + D are consistent with zero. The 1 + D state occurs in the π + ω case but not in the K − ω system, nor in the K ππ − system produced in the K − p → K ππ p reaction.
No description provided.
No description provided.
FROM BREIT-WIGNER FIT TO B EVENTS AND CORRECTED FOR UNSEEN OMEGA DECAY MODES.
The cross sections for the line-reversed reaction pairs K+n→K0p and K−p→K¯0n, and K+p→K0Δ++ and K−n→K¯0Δ− have been determined with high statistics and good relative normalization at 8.36 and 12.8 GeV/c in a spectrometer experiment at Stanford Linear Accelerator Center. The cross sections for the K+-induced reactions are larger than for the K−, contrary to the expectations of weakly-exchange-degenerate Regge-pole models. The ratio of the reaction cross sections is about the same as at lower energies and shows little change with momentum transfer.
Axis error includes +- 11/11 contribution.
Axis error includes +- 11/11 contribution.
Axis error includes +- 11/11 contribution.
By using (pp) interactions at three different c.m. energies,\(\left( {\sqrt 8 } \right)_{pp} \)=30, 44, 62 GeV, it is shown that the average charged-particle multiplicity <nch>vs. the invariant mass of the hadronic systemm1,2 has the same behaviour as it hasvs. 2Ehad. Moreover, in both cases <nch> is shown to be nearly independent of\(\left( {\sqrt 8 } \right)_{pp} \) and in good agreement with the average charged-particle multiplicity measured in the (e+e−) annihilation.
WITH SQRT(S) OF 30 GEV.
WITH SQRT(S) OF 44 GEV.
WITH SQRT(S) OF 62 GEV.
Using the DASP detector at the DESY storage ring DORIS we have continued measuring e + e − annihilations near and on the ϒ(9.46) resonance. From the cross sections for e + e − → μ + μ − and e + e − → hadrons we obtain a μ + μ − branching ratio for the ϒ(9.46) of (2.9 ± 1.3 ± 0.5) %, a leptonic width г ee = (1.35 ± 0.11 ± 0.22) keV and a total width of (47 −15 +37 keV.
No description provided.
A new measurement of the differential cross section and of the analysing power A 0 n of the charge-exchange reaction p − p → n − n at 875 MeV/ c is presented. The A 0 n data cover the entire angular range and constitute a considerable improvement over previously published data, both in the forward and in the backward hemisphere. The cross-section data cover only the backward region, but are unique at this energy. A careful study of the long-term drifts of the apparatus has allowed to fully exploit the good statistics of the data.
Forward hemisphere measurement. Additional systematic error of 4 pct due to target polarization uncertainty.
Backward hemisphere measurement. Additional systematic error of 15 pct.
Differential cross section in the backward hemisphere. Additional systematic error of 15 pct.
We present experimental data on the K L 0 p → K S 0 p reaction between 4 and 14 GeV/ c in the range 0.1 ≲ | t | ≲ 2 GeV 2 . This experiment has been performed at the CERN PS, using spark chambers and a large aperture magnet. The results show a break of slope at t = −0.3 GeV 2 . The ω trajectory deduced from the data has an intercept α (0) = 0.5 and a slope α ′ = 0.88. A comparison with various models shows that the non-flip amplitude is dominant.
No description provided.
The cross section for the K L 0 p elastic scattering has been measured for the first time. The incident momentum and momentum transfer ranges are 3 ⩽ p ⩽ 13 GeV/ c , 0.1 ⩽ | t | ⩽ 1.3 GeV 2 . The results are compared to those of other experiments related to ours by isotopic spin conservation, finding agreement with some and discrepancies with others. The differential cross sections have been parametrized in the form A e bt . The coefficients show little or no dependence on energy, with A ≅ 9.8 mb · GeV −2 and b ≅ 4.7 GeV −2 . The effective linear trajectory has been determined and gives α 0 = 0.95 ± 0.15, α ′ = −0.35 ± 0.48 GeV −2 , in good agreement with dominance by pomeron exchange.
CROSS SECTIONS DEDUCED FROM THE 46 PCT OF EVENTS WHICH YIELD UNIQUE SOLUTIONS.
<RAW> CROSS SECTIONS DEDUCED FROM A STATISTICAL TREATMENT OF ALL EVENTS.
<SMOOTHED> CROSS SECTIONS DEDUCED FROM A STATISTICAL TREATMENT OF ALL EVENTS.
We present a measurement of the total cross section for γγ→hadrons, with one photon quasireal and the other a spacelike photon of mass squared −Q2. Results are presented as a function of Q2 and the γγ center-of-mass energy W, with the Q2 range extending from 0.2 to 60 GeV2, and W in the range from 2 to 10 GeV. The data were taken with the TPC/Two-Gamma facility at the SLAC e+e− storage ring PEP, which was operated at a beam energy of 14.5 GeV. The cross section exhibits a gentle falloff with increasing W. Its Q2 dependence is shown to be well described by an incoherent sum of vector-meson and pointlike scattering over most of the observed W range. Agreement at high Q2 is improved if a minimum-pT cutoff (motivated by QCD) is imposed on the pointlike contribution.
Errors are statistical only.
Errors are statistical only.
Errors are statistical only.
The cross sections for e + e − → hadrons, e + e − , μ + μ − have been measured in the vicinity of the J Ψ resonance using the BES detector operated at BEPC. The partial widths for J Ψ to hadrons, electrons, muons and the total width have been determined to be Γ h = 74.1 ± 8.1 keV, Γ e = 5.14 ± 0.39 keV, Γ μ = 5.13 ± 0.52 keV, and Γ = 84.4 ± 8.9 keV, respectively.
No description provided.
An experiment has been completed at the Daresbury synchrotron to measure the asymmetry in the photoproduction cross section of neutral pions on hydrogen, for photons polarised normal to and in the production plane. The source of polarised photons was coherent bremsstrahlung of electrons traversing the lattice structure of diamond and the polarisation P of the γ beam was calculated from the measured intensity of the coherent spike. The asymmetry parameter Σ, defined as Σ = ( σ ⊥ − σ |)/( σ ⊥ + σ |) where σ ⊥( σ |) are the cross sections for photons polarised perpendicular (parallel) to the production plane, has been measured over a range of photon energies from 1.2 to 2.8 GeV and over a range of − t (the square of the four-momentum transfer) from 0.13 (GeV/ c ) 2 to 1.4 (GeV/ c ) 2 . A marked energy variation in the value of Σ is found over the energy region 1.6–1.8 GeV.
Axis error includes +- 0.0/0.0 contribution (?////).
Axis error includes +- 0.0/0.0 contribution (?////).
Axis error includes +- 0.0/0.0 contribution (?////).
We present a measurement of the cross section for the reaction e + e − → e + e − π + π − π + π − at SPEAR. This channel is found to be large and dominated by the process γγ → ϱ 0 ϱ 0 → π + π − π + π − . The cross section, which is small just above the four-pion threshold, exhibits a large enhancement near the ϱ 0 ϱ 0 threshold.
Axis error includes +- 0.0/0.0 contribution (THE QUOTED ERRORS INCLUDE VARIOUS SYSTEMATIC ERRORS ADDED QUADRATICALLY).
The polarization parameter has been measured for π − p elastic scattering in the backward region at 3.5 GeV/ c incident momentum. The experimental set-up consisted of a polarized target in a spectrometer magnet, hodoscopes and wire spark chambers. Data are presented for the range −0.95< u ⩽−0.19 GeV 2 . An isospin analysis has been carried out to separate the I u = 1 2 and I u = 3 2 contributions.
BACKWARD SCATTERING.
We have measured the polarization parameter in π − p→K + Σ − backward scattering at 3.5 GeV/ c incident momentum, in the u -range −0.6< u <0.1 GeV 2 . The apparatus consisted of a polarized target in a spectrometer magnet, counter hodoscopes for time-of-flight measurements, a large water Čerenkov counter for kaon tagging, and wire spark chambers. After identification of the kaons, the reaction was selected by a missing-mass technique. An isospin analysis has been carried out to separate the contributions of the various isospin exchange amplitudes in the u -channel.
No description provided.
The cross-section ratio of neutral-current and charged-current semileptonic interactions of muon-neutrinos on isoscalar nuclei has been measured with the result:Rv=0.3093±0.0031 for hadronic energy larger than 4 GeV. From this ratio we determined the electroweak mixing angle sin2θW, wheremc is the charm-quark mass in GeV/c2. Comparison with direct measurements ofmw andmz determines the radiative shift of the intermediate boson mass Δr=0.077±0.025(exp.)±0.038(syst.), in agreement with the prediction. Assuming the validity of the electroweak standard theory we determined ϱ=0.990−0.013(mc−1.5)±0.009(exp.)±0.003(theor.).
No description provided.
No description provided.
STATISTICAL ERROR IN THE VALUE CITED IS REDUCING, WHEN CUT IS MORE STRINGENT?.
We present a measurement of the muon neutrino-nucleon inclusive charged current cross-section, off an isoscalar target, in the neutrino energy range $2.5 \leq E_\nu \leq 40$ GeV. The significance of this measurement is its precision, $\pm 4$% in $2.5 \leq E_\nu \leq 10$ GeV, and $\pm 2.6$% in $10 \leq E_\nu \leq 40$ GeV regions, where significant uncertainties in previous experiments still exist, and its importance to the current and proposed long baseline neutrino oscillation experiments.
Inclusive muon-neutrino charged current cross section.
We present a new determination of the nonsinglet structure function ${\mathit{F}}_{2}^{\mathit{p}}$ - ${\mathit{F}}_{2}^{\mathit{n}}$ at ${\mathit{Q}}^{2}$=4 ${\mathrm{GeV}}^{2}$ using recently measured values of ${\mathit{F}}_{2}^{\mathit{d}}$ and ${\mathit{F}}_{2}^{\mathit{n}}$/${\mathit{F}}_{2}^{\mathit{p}}$. A new evaluation of the Gottfried sum is given, which remains below the simple quark-parton model value of 1/3.
Errors of F2(D) are the estimated total uncertainties and those on the ratio and difference are statistical only.
Values of the Gottfried Sum Rule integral (GS) defined as the integral between X(C=MIN) and X = 0.8 of (F2(P)-F2(N))DX/X.
No description provided.
None
ASSUMING ABS(GE)=ABS(GM).
No description provided.
No description provided.
We present the results and the analysis of a high-statistics experiment to study A 2 and g production in the reaction π − p→K − K S 0 p at 10 GeV/ c . In each resonance region we perform a moment analysis of the data, and from the moments we determine the production amplitudes as a function of t . We find A 2 production proceeds dominantly by natural-parity (pomeron and f) exchange. We compare A 2 and diffractive K ∗ (1420) production. We find g production proceeds by π and ω exchanges; we determine the g → K K branching ratio.
No description provided.
No description provided.
A study of inclusive Ξ − production from a high statistics K − p experiment at 4.2 GeV/ c has been made. The total Ξ − production cross section is 157 ± 8 μ b. Approximately 15% of the Ξ − arise from decay of the Ξ ∗0 (1530) resonance. The polarization of the Ξ − is found to be negative and is nearly equal in value to that of the Λ 0 from the inclusive reaction K − + p → Λ 0 + anything. An analysis of the inclusive production of Ξ − has been made in the framework of the triple-Reege formalism.
No description provided.
No description provided.
We perform an amplitude analysis of 10 GeV/ c π − p → K − K S 0 p data as a function of K − K 0 mass from threshold up to 2 GeV. We find that the A 2 and g resonances are produced dominantly by natural and unnatural parity exchange, respectively, and we determine their resonance parameters. We present further evidence for the I = 1, 4 + state A 2 ∗ (1900), in particular by isolating interference effects. The structure of S-wave K − K 0 production suggests an I = 1, 0 + state just below 1300 MeV of width about 250 MeV.
CROSS SECTIONS FROM FITTING MASS SPECTRUM. THE RESONANT AMPLITUDE CONTRIBUTIONS ALSO GIVEN IN PAPER.
The K π − system produced in the reaction K p → K 0 π − p at 4.2 GeV/ c is studied using high-statistics bubble-chamber data. The spin-parity structure is analysed as a function of the K 0 π − mass up to 1.52 GeV. Production of K ∗ (890) and K ∗ (1420) is observed in helicity-0 and helicity-1 states. Contributions of natural and unnatural parity exchange are present. Considerable S-wave production is observed over the whole mass region considered. We also study the t ′ dependence of the K ∗ (890) and K ∗ (1420) amplitudes. A comparison of our results on K ∗ (890) production with the results of an analysis of charge-exchange K ∗ (890) production, allows the separation of I = 0 and I = 1 exchange amplitudes. Some qualitative remarks are made concerning K ∗ (1420) production.
No description provided.
PARTIAL WAVE ANALYSIS ASSUMING SPIN-COHERENCE TO OBTAIN SPIN-PARITY STRUCTURE AND T DEPENDENCE OF P-WAVE AND D-WAVE AMPLITUDES.
We present results on three reactions involving neutral final states which were studied in a magnet spark chamber system. These results are: (a) differential cross section with high statistics for K − p → K 0 n at 5 GeV /c (24 000 events) and at 8 GeV/ c (11 000 events) for t′ <2.0 (GeV/ c ) 2 ; (b) differential cross section and polarization for K − p → Λπ 0 (backward peak) at 5 GeV/ c for u ′ < 1.4 GeV/ c ) 2 ; and (c) differential cross section for K − p → K 0 Δ 0 (1232) at 5 GeV /c for t′ < 1.2 ( GeV /c) 2 . We compare our results with existing data and draw some phenomenological conclusions.
Axis error includes +- 0.0/0.0 contribution (?////TP INDEPENDENT CORRECTIONS AT 5 AND 8 GEV ARE 5.143 +- 0.418 AND 4.981 +- 0.436 RESPECTIVELY).
Axis error includes +- 0.0/0.0 contribution (?////TP INDEPENDENT CORRECTIONS AT 5 AND 8 GEV ARE 5.143 +- 0.418 AND 4.981 +- 0.436 RESPECTIVELY).
Axis error includes +- 0.0/0.0 contribution (?////UP INDEPENDENT CORRECTION FACTOR IS 3.840 +- 0.323).
Differential cross sections and polarizations are presented for the reactions K − p → Λπ 0 , Λη , Λη ′ at 8.25 GeV/ c incident K − momentum. The data, which come from a high statistics experiment in the CERN 2 m bubble chamber, are compared with previous experimental results on the same reactions and with current theoretical ideas.
No description provided.
No description provided.
No description provided.
Results are presented concerning K − d and K − n elastic scattering at an incident momentum of 4.5 GeV/ c . The high-energy Glauber formalism has been used in analyzing the data in which the nucleon scattering amplitudes are parameterized and employing the spherical and quadrupole deuteron form factors. An impulse approximation analysis of the K − n differential scattering cross section fitted to a single exponential of the form d σ /d t ) 0 e Bt , leads to the result (d σ /d t ) 0 = 21.3 + mn ; 5.5 mb/(GeV/ c ) 2 and B = 6.9 + mn ; 0.5 (GeV/ c ) −2 . A global fit has been made to existing K + mn; N two-body scattering data at this energy in order to determine the scattering amplitudes. It was found that the K − n and K − p elastic amplitudes are dominantly imaginary with a relatively small contribution from spin-flip amplitudes. The slopes of the differential elastic cross sections for K − n and K − p are nearly equal, as are those for K + n and K + p. However, the value of the slope for K + is smaller than that for K − at this energy.
No description provided.
No description provided.
Cross sections, differential cross sections, and hyperon polarization results are presented for the reactions K¯0p→Λπ+ and K¯0p→Σ0π+ in the momentum interval 1 to 12 GeV/c. Emphasis is placed on the comparison of Λ and Σ channels, and on the momentum dependences of the data. In particular, the Λ polarization data are consistent with being independent of energy above 2 GeV/c; and the slopes of the forward cross sections are found to increase toward the slope values for the line-reversed reactions πp→K(Λ,Σ) as energy increases.
No description provided.
No description provided.
RESONANCE REGION CROSS SECTIONS.
We have measured with good statistics the differential cross section for p p →π + π − , K + K − around 0°. Our data and previous results show that the s -dependence of dσ/d t has a value compatible with the appropriate baryon exchange.
No description provided.
No description provided.
No description provided.
We present a next-to-leading order QCD analysis of the presently available data on the spin structure function g1 including the final data from the Spin Muon Collaboration. We present results for the first moments of the proton, deuteron, and neutron structure functions, and determine singlet and nonsinglet parton distributions in two factorization schemes. We also test the Bjorken sum rule and find agreement with the theoretical prediction at the level of 10%.
The second systematic (DSYS) error is due to QCD evolution.
First moments of the fitted function G1 evaluated on unmeasured X regions. Total uncertainties due to experimental systematics and theoretical sourc es in the QCD evolution.
Integrals of the nonsinglet (NS) structure function. SMC + E143 data.
None
No description provided.
No description provided.
No description provided.
$K^0_SK^0_S$ production in two-photon collisions has been studied using a 397.6 fb$^{-1}$ data sample collected with the Belle detector at the KEKB $e^+e^-$ collider. For the first time the cross sections are measured in the two-photon center-of-mass energy range between 2.4 GeV and 4.0 GeV and angular range $|\cos\theta^*|<0.6$. Combining the results with measurements of $\gamma\gamma\to K^+K^-$ from Belle, we observe that the cross section ratio $\sigma(K^0_SK^0_S)/\sigma(K^+K^-)$ decreases from ~0.13 to ~0.01 with increasing energy. Signals for the $\chi_{c0}$ and $\chi_{c2}$ charmonium states are also observed.
Total cross section for the process GAMMA GAMMA --> K0S K0S.
Angular distribution of the cross section in the W range 2.4 to 2.5 GeV.
Angular distribution of the cross section in the W range 2.5 to 2.6 GeV.
We present an analysis of the K ππ system produced in 10 GeV/ c K + p interactions. We show that the low-mass enchancement between 1.2 and 1.4 GeV/ c 2 on the K ππ mass spectrum is predominantly 1 + throughout, give the relative amplitudes for the decay of this system into K ∗ (890) π and K ρ , and offer new evidence for the presence of two 1 + resonances in this mass region.
No description provided.
DIFFERENTIAL CROSS SECTION FOR THREE MASS BANDS IN Q-REGION. NORMALIZATION UNCERTAIN - NO UNITS FOR D(SIG)/DT GIVEN ON FIGURE. NUMERICAL VALUES TAKEN FROM THE COMPILATION LST7V2 FOX 72B. ERRORS ADDED AS 1/SQRT(EVENTS).
A study of strange particle production in muon neutrino charged current interactions has been performed using the data from the NOMAD experiment. Yields of neutral strange particles K0s, Lambda, AntiLambda have been measured. Mean multiplicities are reported as a function of the event kinematic variables Enu, W2 and Q2 as well as of the variables describing particle behaviour within a hadronic jet: xF, z and pT2. Decays of resonances and heavy hyperons with identified K0s and Lambda in the final state have been analyzed. Clear signals corresponding to K*+-, Sigma*+-, Xi- and Sigma0 have been observed.
Measured yields of the neutral strange particles measured in this analysis.The second line (marked *) is a recalculation taking into account contributions from both primary and secondary V0. The values for K0 are the K0S rates multipl ied by 2.
Measured yields as a function of E, the neutrino energy.
Measured yields as a function of W**2.
The experimental results are presented for ratios of ν-meson inclusive differential cross sections in 10.5 GeV/ c π + p, π + D and π + A collisions, R D/p =(d σ /d x F )( π + D → η X)/ (d σ /d x F ) π + p→ η X), R A =(d σ /d x F )( π + D→ η X) in the beam fragmentation region. The results are based on the statistics of ≈ 5 × 10 4 detected η → 2 γ decays. It is shown that the power α in the parametrisation R A ≈ A α ( xf ) does not change significantly with x F and its mean value is 0.50±0.02. The lower limit is obtained for the effective coefficient with string tension in the colour string model, κ ⩾ 3 GeV/fm. The observed growth of R A with x F can be explained by an assumption of a neutron halo with the factor H ≈ 4 in the nuclei.
No description provided.
Results of two spark chamber experiments on A 2 − production in the reaction π − p → K − K S 0 (→ π + π − )p at 9.8 and 18.8 GeV are presented. Decay angular distributions and differential cross sections are given, and the energy dependence of the cross section σ [ π − p → A 2 − (→ K − K 0 )p] is compared with results from π − p → A 2 − (→ 3 π )p.
FITS WITH CONSTANT BACKGROUNDS. A TWO-PARAMETER LINEAR BACKGROUND GIVES MUCH LARGER ERRORS.
INTEGRATED OVER M(K AK) = 1.20 TO 1.42 GEV.
No description provided.
None
'1'. '2'. '3'.
No description provided.
No description provided.
High statistics data for the reactions K ± p → K S 0 π ± p at 10 GeV/ c are analysed. The K ∗ (1 − ), K ∗ (2 + ), and K ∗ (3 − ) resonance parameters and production cross sections are calculated. The Kπ production amplitudes are determined as a function of t and the produced Kπ mass. Isoscalar natural-parity-exchange (NPE) is dominant. The t dependence of the K ± NPE amplitudes have a cross-over at t = −0.3 (GeV/ c ) 2 for both K ∗ (890) and K ∗ (1420) production, being more pronounced for the K ∗ (1420). Natural-parity-exchange interference effects are isolated. The NPE amplitudes are decomposed into pomeron-, f-, and ω-exchange contributions. S-wave Kπ production is found to be consistent with the Kπ partial-wave analyses of charge-exchange reactions.
CORRECTED FOR BACKGROUND, BREIT-WIGNER TAILS AND T-ACCEPTANCE. SYSTEMATIC ERROR INCLUDED.
A study of elastic scattering, one-pion production and annihilation reactions in p p interactions at 5.7 GeV/ c was carried out, from the two-prong events, obtained in the hydrogen bubble chamber exposed at CERN.
NUMBER OF EVENTS FOR -T<0.03 GEV**2 CALCULATED BY EXTRAPOLATION.
No description provided.
The reactions gamma gamma -> pi^+pi^-pi^+pi^- and gamma gamma -> pi^+pi^0pi^-pi^0 are studied with the L3 detector at LEP in a data sample collected at centre-of-mass energies from 161GeV to 209GeV with a total integrated luminosity of 698/pb. A spin-parity-helicity analysis of the rho^0 rho^0 and rho^+ rho^- systems for two-photon centre-of-mass energies between 1GeV and 3GeV shows the dominance of the spin-parity state 2+ with helicity 2. The contribution of 0+ and 0- spin-parity states is also observed, whereas contributions of 2- states and of a state with spin-parity 2+ and zero helicity are found to be negligible.
Cross section for 4PI and (RHO0 RHO0) production.
Cross section for 4PI and (RHO+ RHO-) production.
Spin parity analysis fits for RHO0 RHO0.
We report on a determination of the analyzing power Ay in the reaction studied with the TOF spectrometer located at the COSY-accelerator (Forschungszentrum Juelich, Germany). This spectrometer is very well suited for polarization measurements due to its rotational symmetry and full coverage of the azimuthal angle. For a beam momentum of p=3065MeV/c corresponding to an excess energy of epsilon (Porson) =129MeV Ay is found to be compatible with zero.
Analysing power measurements.
Experimental results are presented for the pp elastic-scattering single spin observable Aoono=Aooon=AN=P, or the analyzing power, at 19 beam kinetic energies between 1795 and 2235 MeV. The typical c.m. angular range is 60–100°. The measurements were performed at Saturne II with a vertically polarized beam and target (transverse to the beam direction and scattering plane), a magnetic spectrometer and a recoil detector, both instrumented with multiwire proportional chambers, and beam polarimeters.
Measurement values of the P P analysing power at kinetic energy 1.795 GeV. The relative and additive systematic errors are +- 0.106 and 0.003.
Measurement values of the P P analysing power at kinetic energy 1.845 GeV. The relative and additive systematic errors are +- 0.068 and 0.001.
Measurement values of the P P analysing power at kinetic energy 1.935 GeV. The relative and additive systematic errors are +- 0.091 and 0.003.
Measurements at 18 beam kinetic energies between 1975 and 2795 MeV and at 795 MeV are reported for the pp elastic scattering spin correlation parameter A00nn=(N,N;0,0)=CNN=ANN. The c.m. angular range is typically 60°-100°. These results are compared to previous data from Saturne II and other accelerators. A search for energy-dependent structure at fixed c.m. angles is performed. Comparisons are made to phase shift analysis and theoretical model predictions of this spin observable.
Measured values of CNN at EKIN 795 Mev.. Fractional systematic uncertainty in the absolute beam and target polarization is +-0.032.
Measured values of CNN at EKIN 1975 Mev.. Fractional systematic uncertainty in the absolute beam and target polarization is +-0.052.
Measured values of CNN at EKIN 2035 Mev (from run period III).. Fractional systematic uncertainty in the absolute beam and target polarization is +-0.051.
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