Differential cross sections have been measured for nucleon-isobar production and elastic scattering in p−p interactions from 6.2 to 29.7 GeVc in the laboratory angle range 8<θsc<265 mrad. N*' s at 1236, 1410, 1500, 1690, and 2190 MeV were observed. Computer fits to the mass spectra under varying assumptions of resonance and background shapes show that conclusions on t and s dependence are only slightly affected despite typical variations in absolute normalization of ± 35%. Logarithmic t slopes in the small- |t| range are ∼15 (GeVc)−2 for the N*(1410), ∼5 (GeVc)−2 for the N*'s at 1500, 1690, and 2190 MeV, and ∼9 (GeVc)−2 for elastic scattering. Also for the small- |t| data, cross sections for N*'s at 1410, 1500, 1690, and 2190 MeV and for elastic scattering vary only slightly with Pinc consistent with the dominance of Pomeranchuk exchange and with diffraction dissociation. A fit of N*(1690) total cross sections to the form σ∝P−n gives n=0.34±0.06, while for elastic scattering n=0.20±0.05. For the N*(1690) the effective Regge trajectory has the slope αeff′(0)=0.38±0.17. When compared with N* production in π−, K−, and p¯ beams these data also agree with approximate factorization of the Pomeranchuk trajectory. N*(1236) cross sections are consistent with other measurements at similar momenta. For −t>1 (GeVc)−2, elastic scattering cross sections decrease approximately as Pinc−2, and they and N*(1500)− and N*(1690)− production cross sections have t slopes consistent with 1.6 (GeVc)−2.
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.
A partial-wave analysis has been performed of the diffractively produced low-mass ( K ̄ 0 π − π 0 ) system in the reaction K − p → ( K ̄ 0 π − π 0 ) p at 10 and 16 GeV/ c . Thus information complementary to that derived from the K − p → (K − π + π − )p) channel is obtained. The presence of the K ϱ decay mode, besides the dominant K ∗ (890)π mode, for the state J P = 1 + , is confirmed. It is also confirmed that for this 1 + state the assumption of factorization of the amplitude into “production” and “decay” does not hold: the two decay modes K ∗ π and K ϱ have different polarisation properties (helicity is approximately conserved in the t -channel for the first, in the s -channel for the second). The assumption that the ( K ̄ 0 π − π 0 ) system has isospin I = 1 2 has been tested and found to hold. From the cross sections for the various J P states, assuming I = 1 2 , the cross sections for the (K − π + π − ) system are predicted and compared with the experimental ones. In general, agreement is found.
No description provided.
No description provided.
Inclusive cross sections and one-particle inclusive spectra are given for neutral K, Λ and Λ produced in K − p and K + p interactions at 32 GeV/ c in the 4.5 m Mirabelle hydrogen bubble chamber at the Serpukhov accelerator. Cross sections for associated production are also given, and the energy dependences of the cross sections and of the x distributions in the central and in the fragmentation regions are discussed.
No description provided.
No description provided.
None
No description provided.
No description provided.
A high-statistics measurement of the differential cross-sections for neutrino-iron scattering in the wide-band neutrino beam at the CERN SPS is presented. Nucleon structure functions are extracted and theirQ2 evolution is compared with the predictions of quantum chromodynamics.
No description provided.
No description provided.
No description provided.
Elastic scattering of p¯ on p has been studied for cosθc.m. between -0.88 and -1.0 and Plab(p¯) between 0.70 and 2.16 GeV/c. The momentum dependence of the cross section shows a sharp dip at 0.9 GeV/c and a broad peaking around 1.4 GeV/c. The possibility of the peak resulting from direct formation of boson resonances has been studied. Alternatively, a diffraction model agrees qualitatively with our data and other elastic data at different angles.
'1'. '2'. '3'.
No description provided.
No description provided.
Results on inclusive K s 0 production in e + e − annihilation at mean center-of-mass energies of 9.4, 12.0 and 30 GeV are presented. The ratio R (K 0 ) = 2 σ (K s 0 )/ σ μμ rises from 3.10 ± 0.75 at √ s = 9.4 GeV to 5.6 ± 1.2 at √ s = 30 GeV, corresponding to an approximately constant K 0 /charged-particle ratio of 0.12 ± 0.02. A similar ratio for K 0 / charged particle is observed for direct hadronic decays of the ϒ.
SYSTEMATIC ERROR INCLUDED.
NUMBER OF K0 PER HADRONIC EVENT. AUTHORS ALSO USE MULTIPLICITY TO ESTIMATE NUMBER OF K0 PER CHARGED PARTICLE.
INCLUDING EARLIER DATA.
After completion of the data taking for the νμ→ντ oscillation search, the CHORUS lead–scintillator calorimeter was used in the 1998 run as an active target. High-statistics samples of charged-current interactions were collected in the CERN SPS west area neutrino beam. This beam contained predominantly muon (anti-)neutrinos from sign-selected pions and kaons. We measure the flux and energy spectrum of the incident neutrinos and compare them with beam simulations. The neutrino–nucleon and anti-neutrino–nucleon differential cross-sections are measured in the range 0.01<x<0.7 , 0.05<y<0.95 , 10<Eν<200 GeV . We extract the neutrino–nucleon structure functions F2(x,Q2) , xF3(x,Q2) , and R(x,Q2) and compare these with results from other experiments.
The measured F2 and xF3 at X = 0.020.
The measured F2 and xF3 at X = 0.045.
The measured F2 and xF3 at X = 0.080.
In a K − p experiment at 32 GeV/ c with a sensitivity of 6 ev/≈b the inclusive reaction K − p → p + X was studied in the kinematical region x < −0.3. Most of the protons in this region were identified by ionization. Correcting for losses of the very slow as well as of the fast protons in this region we obtained σ p ( x < −0.3) = 5.9 ± 0.2 mb. The double invariant differential cross sections of protons were analysed in terms of the variables x , p T 2 , and M 2 / s , t , and the contributions from separate peripheral mechanisms were analysed. A triple-Regge analysis was performed on the inclusive proton d 2 σ /d t d( M 2 / s ) distribution with | t | < 1.1 GeV 2 . The fit with an RRP term resulted in an effective trajectory for the exchanged reggeon lying somewhat lower than that for the leading meson trajectory. Inclusion in the fit of an additional ππp term showed that pion exchange is important in the triple-Regge region at small | t |.
No description provided.
No description provided.
A study is presented of the inclusive production cross sections of K ∗± (892) vector mesons in pp interactions at 12 and 24 GeV/ c and in π + p interactions at 16 GeV/ c . The K ∗± inclusive cross section is ∼0.9 mb for both pp at 24 GeV/ c and π + p interactions at 16 GeV/ c . For pp interactions, σ( K ∗+ ) and σ( K ∗− ) are seen to rise with energy, showing a threshold behaviour. In both pp and π + p interactions, σ( K ∗+ ) largely exceeds σ( K ∗− ) at these energies and this excess is interpreted as K ∗+ production by beam and target fragmentations. The decays of K ∗±0 yield ∼30% of the K 0 observed in the final states. The p T 2 dependence of both K ∗+ and K ∗ − cross sections is described by an exponential with slope of ∼3.3 (GeV/ c ) −2 . The longitudinal momentum spectra for K ∗+ in 16 GeV/ c π + p and 24 GeV/ c pp interactions are similar in shape in the target hemisphere. The K ∗− spectra are similar over the whole kinematic region when viewed in the quark c.m.s. and point to a central production mechanism. Comparing K ∗+ and ρ 0 production, striking similarities are found.
No description provided.
ASSUMED SIG(KS)=SIG(KL).
No description provided.
Inclusive and semi-inclusive distributions of γ's and π 0 's in the reactions K + p → γ + X and K + p → π 0 + X at 32 GeV/ c are presented and discussed. When compared to the inclusive π − production, the π 0 cross section is found to be significantly higher in low | x | and p T regions. The data are compared with other experiments and quark fusion model predictions.
No description provided.
No description provided.
ESTIMATED FROM GAMMA AND 2GAMMA SPECTRA.
Inclusive production of Δ ++ (1232) with >| t p, Δ ++>|<0.6 (GeV/ c ) 2 is studied in 32 GeV/ c K + p interactions. A systematic comparison with the reaction K + p→pX for >| t p,p>| < 0.6 (GeV/ c ) 2 is made. The production properties of the Δ ++ (1232), of associated π + , π − and K 0 production and of the recoiling system X 0 are investigated in detail. The polarization of the Δ ++ and the energy dependence of the total K + π − cross sections, determined by a Chew-Low extrapolation, are presented and discussed.
No description provided.
No description provided.
No description provided.
Inclusive charged-current interactions of high-energy neutrinos and antineutrinos have been studied with high statistics in a counter experiment at the CERN Super Proton Synchrotron. The energy dependence of the total cross-sections, the longitudinal structure function, and the nucleon structure functionsF2,xF3, and\(\bar q^{\bar v} \) are determined from these data. The analysis of theQ2-dependence of the structure functions is used to test quantum chromodynamics, to determine the scale parameter Λ and the gluon distribution in the nucleon.
ABSOLUTE FLUXES HAVE NOT BEEN MEASURED. NORMALISED TO OLD RESULTS.
STUCTURE FUNCTIONS ARE EVALUATED ASSUMING R=SIG(L)/SIG(T)=0.1 AND M(W) IS INFINITE. NO CORRECTION FOR FERMI MOTION APPLIED. ERRORS ARE STATISTICAL AND SYSTEMATIC POINT-TO-POINT ERRORS. IN ADDITION OVER-ALL SCALE ERROR OF 6 PCT. FOR F2 , 8 PCT. FOR XF3.
STUCTURE FUNCTIONS ARE EVALUATED ASSUMING R=SIG(L)/SIG(T)=0.1 AND M(W) IS INFINITE. NO CORRECTION FOR FERMI MOTION APPLIED. ERRORS ARE STATISTICAL AND SYSTEMATIC POINT-TO-POINT ERRORS. IN ADDITION OVER-ALL SCALE ERROR OF 6 PCT. FOR F2 , 8 PCT. FOR XF3.
None
No description provided.
No description provided.
No description provided.
The azimuthal dependence of the flow of hadronic energy about the momentum-transfer direction in charged-current deep-inelastic neutrino-nucleon scattering is used to study gluon emission and the transverse momentum 〈kT〉 of partons confined inside the nucleon. A 7-standard-deviation azimuthal asymmetry is observed indicating an average 〈kT〉=0.303±0.041 GeV/c.
No description provided.
No description provided.
No description provided.
We have measured the inclusive cross section for η production in e+e− interactions near charm threshold using the Crystal Ball detector. No pronounced structure in the energy dependence is observed. By comparing cross sections above and below charm threshold we obtain the limits (90% confidence limit): R(e+e−→FF¯X)RB(F→ηx)<0.15−0.32 (for Ec.m. from 4.0 to 4.5 GeV), RB(D→ηx)<0.13. Our results are inconsistent with a previous report of a large energy dependence of the η cross section ascribed to the crossing of the FF* and F*F* production thresholds.
Axis error includes +- 0.0/0.0 contribution (?////DECAY PI0 --> 2GAMMA//RES-DEF(RES=ETA,BACK=CORRECTED,DEF=340 < M( 2GAMMA ) < 800 MEV)//DECAY-BR(BRN=ETA --> 2GAMMA,BR=38 PCT)).
THE 4.028 GEV DATA ARE NOT INCLUDED IN THE 4.005-4.082 GEV BIN. Axis error includes +- 0.0/0.0 contribution (?////DECAY PI0 --> 2GAMMA//RES-DEF(RES=ETA,BACK=CORRECTED,DEF=340 < M( 2GAMMA ) < 800 MEV)//DECAY-BR(BRN=ETA --> 2GAMMA,BR=38 PCT)).
AT FIXED ENERGIES.
None
No description provided.
DIFFRACTION DISSOCIATION EVENTS.
NON-DIFFRACTION EVENTS.
A method for the determination of neutron spectra in a bubble chamber experiment is developed. Double differential cross sections for inclusive neutron and lambda production are presented. The n/Λ particle ratios are determined as functions of x and p T ; at p T = 0 GeV/ c they are compatible with the ratios measured in pCu interactions at 24 GeV/ c . Our neutron spectra are compared with spectra for protons produced near the direction of the incident neutron in pn interactions at FNAL and with neutron spectra measured in pp interactions at the ISR. Exchange mechanisms are studied in the framework of single diffraction dissociation and the triple-Regge model. The scattering of virtual pions and kaons on real protons is investigated.
No description provided.
No description provided.
No description provided.
The production of ρ 0 (770) and f(1270) is studied in π − p interactions at 16 GeV/ c . By comparison with inclusive K ∗0 production in the reaction K − p → K ∗0 + anything, and with inclusive ρ 0 production in the reaction pp → ρ 0 + anything, it is found that the data can be interpreted in terms of two production processes: the central production of resonances and the fragmentation of the beam particle. For the π − p reaction, the inclusive ρ 0 beam fragmentation cross section is 3.1 ± 0.3 mb while that for central production is 1.6 ± 0.5 mb. The ρ 0 central production cross section is consistent with increasing with energy as ln s behaviour. The ratio of ρ 0 to π − inclusive cross sections (excluding the leading π − ) is ∼0.2, independent of energy. The ρ 0 to π − ratio increases as a function of p T to a constant value of ∼ 1 2 above 1 GeV/ c . The ρ (charged and neutral) and f decays account for (25 ± 4)% and (1.4 ± 0.3)%, respectively, of all pions produced.
No description provided.
No description provided.
No description provided.
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.
VISIBLE HADRONIC CROSS SECTION. PEAK VALUE AT UPSILON IS 10.1 +- 0.7 NB.
No description provided.
Measurements of energy-energy correlations in hadronic final states produced in e + e − annihilation at c.m. energies between 7.7 and 31.6 GeV are presented. The data are compared to perturbative QCD predictions. Good qualitative agreement above 20 GeV c.m. energy is found. The importance of non-perturbative effects is discussed, as well as the detailed behaviour of the correlation near 180°.
No description provided.
OPPOSITE SIDE ENERGY-ENERGY CORRELATIONS NEAR 180 DEG.
ENERGY-ENERGY CORRELATION INTEGRATED IN THE REGION 60 TO 120 DEG.
Inclusive neutrino and antineutrino charged-current interactions were studied using the electronic detector of the CHARM Collaboration exposed to the narrow-band beam of the CERN SPS. The relative contributions of quarks and antiquarks to the neutrino cross sections were deduced from the differential cross sectionsdσ/d y . The x and Q 2 dependence of the structure functions F 2 and F 3 were measured. Scaling violations were observed, in qualitative agreement with QCD. A value of the mass scale parameter of QCD,Λ = [0.29 ± 0.12 (stat.) ± 0.10 (syst.)] GeV, was deduced in a leading-order approximation, following the method of Buras and Gaemers.
No description provided.
No description provided.
No description provided.
Inclusive cross sections and longitudinal momentum distributions are presented for γ rays produced in K − p and K + p interactions at 32 GeV/c in the 4.5 m Mirabelle hydrogen bubble chamber at the Serpukhov accelerator. The average longitudinal and transverse momentum of neutral pions and the average π 0 multiplicity ▪ 〈 n π 0〉 are estimated. It is found that 〈 n π 0〉 is an increasing function of the number of charged prongs.
No description provided.
No description provided.
None
'1'. '2'.
No description provided.
Charged hadron production ine+e− annihilation is studied in the 7 to 10 GeV CM energy region and at the Υ (9.46) and Υ′ (10.01) resonances with the LENA detector at DORIS. The statistical moments of the charged multiplicities are studied. The data show KNO scaling behaviour and suggest the presence of long range correlations. An average charged multiplicityrise of Δn(Υ)=0.55±0.19 and Δn(Υ′)=1.26±0.29 over the continuum is observed for the Υ and Υ′ direct decays. The jet structure of the Υ and Υ′ direct decays is investigated using the charged particles. The polar angular distributions of the jet axis behave like 1+α(T) cos2θ with 〈α(T)〉Υ=0.7±0.3 and 〈α(T)〉Υ′=0.6±0.4. The 〈α(T)〉Υ value is in agreement with the QCD vector gluon assignment and excludes scalar gluons by more than four standard deviations.
No description provided.
No description provided.
No description provided.
Invariant single-particle cross sections for pion and proton production in π ± p interactions at 8 and 16 GeV/ c are presented in terms of integrated distributions as functions of x , reduced rapidity ζ and p ⊥ 2 , and also in terms of double differential cross sections E d 2 σ /(d x d p ⊥ 2 ) and d ζ d p ⊥ 2 ). A comparison of π ± and π − induced reactions is made and the energy dependence is discussed. It is shown that the single-particle structure function cannot be factorized in its dependece on transverse and longitudinal momentum. For the beam-unlike pion, there is an indication for factorizability in terms of rapidity and transverse momentum in a small central region.
No description provided.
No description provided.
No description provided.
This paper presents the results of the analysis of a single-arm inelastic-electron-scattering experiment at an angle of 4°. We present data on the turnon of scaling in the low-q2 region 0.1<q2<1.8, the neutron-proton comparison at large values of the scaling variable ω, resonance excitation, and the shadowing in scattering from heavy nuclei.
No description provided.
No description provided.
No description provided.
We present measurements of the total production rates and momentum distributions of the charmed baryon $\Lambda_c^+$ in $e^+e^- \to$ hadrons at a center-of-mass energy of 10.54 GeV and in $\Upsilon(4S)$ decays. In hadronic events at 10.54 GeV, charmed hadrons are almost exclusively leading particles in $e^+e^- \to c\bar{c}$ events, allowing direct studies of $c$-quark fragmentation. We measure a momentum distribution for $\Lambda_c^+$ baryons that differs significantly from those measured previously for charmed mesons. Comparing with a number of models, we find none that can describe the distribution completely. We measure an average scaled momentum of $\left< x_p \right> = 0.574\pm$0.009 and a total rate of $N_{\Lambda c}^{q\bar{q}} = 0.057\pm$0.002(exp.)$\pm$0.015(BF) $\Lambda_c^+$ per hadronic event, where the experimental error is much smaller than that due to the branching fraction into the reconstructed decay mode, $pK^-\pi^+$. In $\Upsilon (4S)$ decays we measure a total rate of $N_{\Lambda c}^{\Upsilon} = 0.091\pm$0.006(exp.)$\pm$0.024(BF) per $\Upsilon(4S)$ decay, and find a much softer momentum distribution than expected from B decays into a $\Lambda_c^+$ plus an antinucleon and one to three pions.
LAMBDA/C+ differential production rate per hadronic event for the continuum at cm energy 10.54 GeV.
The integrated number of LAMBDA/C+'s per hadronic event for the continuum at cm energy 10.54 GeV.
LAMBDA/C+ differential production rate per UPSILON(4S) decay at cm energy 10.58 GeV.
Measurements of inclusive scattering in the target-fragmentation region are extended to higher incident energy. The combined data set shows departures from an approach to the asymptotic scaling limit as A+Bs−12 that are significant even at the highest energies. When these departures are taken into account, the data approach a limit that is consistent with equal cross sections induced by particles and antiparticles and with Pomeron factorization. The corrections to A+Bs−12 are so large that detailed tests of Mueller-Regge relationships are not conclusive.
No description provided.
No description provided.
No description provided.
In a streamer-chamber experiment at the Stanford Linear Accelerator Center, we observed hadron production in inelastic collisions of 14-GeV positive muons in a liquid hydrogen target. We report on the experiment, the analysis, and the resulting cross sections for hadronic prongs as well as the charged-hadron multiplicity distributions.
No description provided.
No description provided.
We have measured the spin structure functions g2p and g2d and the virtual photon asymmetries A2p and A2d over the kinematic range 0.02 < x < 0.8 and 0.7 < Q^2 < 20 GeV^2 by scattering 29.1 and 32.3 GeV longitudinally polarized electrons from transversely polarized NH3 and 6LiD targets. Our measured g2 approximately follows the twist-2 Wandzura-Wilczek calculation. The twist-3 reduced matrix elements d2p and d2n are less than two standard deviations from zero. The data are inconsistent with the Burkhardt-Cottingham sum rule if there is no pathological behavior as x->0. The Efremov-Leader-Teryaev integral is consistent with zero within our measured kinematic range. The absolute value of A2 is significantly smaller than the sqrt[R(1+A1)/2] limit.
Values of A2 and X*G2 from proton and deuterium target data at mean electron scattering angle of 2.75 degrees and incident energy 29.1 GeV. Errors shown are statistical only.
Values of A2 and X*G2 from proton and deuterium target data at mean electron scattering angle of 5.5 degrees and incident energy 29.1 GeV. Errors shown are statistical only.
Values of A2 and X*G2 from proton and deuterium target data at mean electron scattering angle of 10.5 degrees and incident energy 29.1 GeV. Errors shown are statistical only.
We have measured the spin structure functions g2p and g2d and the virtual photon asymmetries A2p and A2d over the kinematic range 0.02 < x < 0.8 and 1.0 < Q^2 < 30(GeV/c)^2 by scattering 38.8 GeV longitudinally polarized electrons from transversely polarized NH3 and 6LiD targets.The absolute value of A2 is significantly smaller than the sqrt{R} positivity limit over the measured range, while g2 is consistent with the twist-2 Wandzura-Wilczek calculation. We obtain results for the twist-3 reduced matrix elements d2p, d2d and d2n. The Burkhardt-Cottingham sum rule integral - int(g2(x)dx) is reported for the range 0.02 < x < 0.8.
2.75 degree spectrometer data.
5.5 degree spectrometer data.
10.5 degree spectrometer data.
From a 98000-photograph exposure of the BNL 80-in. deuterium-filled chamber to a 14.6-GeV/c p¯ beam we have extracted those events that fit the channel p¯n→p¯pπ−. The cross section for this channel is measured to be 730 ± 50 μb. The cross section for the reaction p¯n→Δ¯−−(1238)p is determined to be 130 ± 30 μb. Evidence for target dissociation is presented. A comparison with the reaction π−n→π−pπ− at the same energy indicates agreement with factorization.
No description provided.
Results on charged pion and kaon production in central Pb+Pb collisions at 20A and 30A GeV are presented and compared to data at lower and higher energies. A rapid change of the energy dependence is observed around 30A GeV for the yields of pions and kaons as well as for the shape of the transverse mass spectra. The change is compatible with the prediction that the threshold for production of a state of deconfined matter at the early stage of the collisions is located at low SPS energies.
Transverse mass spectra for pion production in the central rapidity region for collisions at 20 GeV per nucleon.
Transverse mass spectra for pion production in the central rapidity region for collisions at 30 GeV per nucleon.
Transverse mass spectra for kaon production in the central rapidity region for collisions at 20 GeV per nucleon.
Phi meson production is studied by the NA49 collaboration in central Pb+Pb collisions at 20A, 30A, 40A, 80A and 158A GeV beam energy. The data are compared to measurements at lower and higher energies and to microscopic and thermal models. The energy dependence of yields and spectral distributions is compatible with the assumption that partonic degrees of freedom set in at low SPS energies.
PHI transverse momentum spectra at incident energy 20 GeV/nucleon integrated over the rapidity range 0 to 1.8.
PHI transverse momentum spectra at incident energy 30 GeV/nucleon integrated over the rapidity range 0 to 1.8.
PHI transverse momentum spectra at incident energy 40 GeV/nucleon integrated over the rapidity range 0 to 1.5.
Using the solenoidal magnetic detector PLUTO, we have measured the total cross section for e + e − annihilation into hadrons. Results are presented for center of mass energies between 3.6 and 4.8 GeV, and in the regions of the J ψ (3.1) and ψ(3.7) resonances. We also present results for the 2 prong cross section in the energy range 3.6 to 4.8 GeV.
No description provided.
NUMBERS MEASURED OFF PUBLISHED FIGURE. RADIATIVE CORRECTIONS HAVE BEEN APPLIED.
We have measured the production cross section for K s 0 in e + e − annihilation from 3.6 to 5.0 GeV center of mass energy. A substantial increase of the K s 0 yield is observed around 4 GeV in qualitative agreement with the charm hypothesis.
THE DATA GIVEN HERE AT 9.3 GEV AND ABOVE ARE REPORTED IN C. BERGER ET AL., PL 104B, 79 (1981). THE 12.0 AND 30 GEV DATA WERE TAKEN AT PETRA.
No description provided.
No description provided.
Elastic Σ − p and π − p cross section have been measured at 17.2 GeV/ c in the t interval −0.12, −0.38 (GeV/ c ) 2 . The Σ − p slope is b = 8.12 ± 0.35 (GeV/ c ) −2 .
No description provided.
NORMALIZED TO PI- P ELASTIC FORWARD DIFFERENTIAL CROSS SECTION OF 31.2 +- 1.9 MB/GEV**2 (PLUS 6 PCT SYSTEMATIC ERROR) OF K. J. FOLEY ET AL., PRL 11, 425 (1963).
NUMERICAL VALUES SUPPLIED BY J. J. BLAISING AND ADDED TO RECORD ON 19 DEC 77.
The invariant mass spectrum of neutral meson states from π − p interactions at 40 GeV/ c incident momentum has been investigated in a high statistics experiment performed at the 70 GeV IHEP accelerator. To detect the high energy photons coming from the produced neutral states, a hodoscope spectrometer with a computer on-line was used. A clear structure on the mass spectrum of dipions produced in the reaction π − p→π°π°n is observed at 2 GeV. The decay angular distributions show in this mass region the variation with mass typical of a state with a spin J = 4. The mass of the observed meson is found to be M = (2020±30)MeV and the estimate of the full width is (180±60) MeV.
No description provided.
We report the observation of a spin 4 resonance from the analysis of the reaction π − p→ K + K − n. The mass and width of the h-meson were determined to be 2050 MeV and 225 MeV. The quantum numbers are J P = 4 + , C = +1 and very probably I G = 0 + .
No description provided.
We have studied the quasielastic reaction νμn→μ−p in an exposure of the Fermilab deuterium-filled 15-foot bubble chamber to a high-energy wide-band neutrino beam. From an analysis of the Q2 distribution based on the standard V−A theory, the axial-vector mass in a dipole parametrization of the axial-vector form factor is determined to be MA=1.05−0.16+0.12 GeV, consistent with the values previously reported from low-energy experiments.
Measured Quasi-Elastic total cross section.
The reaction K−p→K¯0π−p has been studied at 100 and 175 GeV/c and the reaction π−p→K0K−p at 50, 100, and 175 GeV/c. Both reactions are dominated by production of resonances, K*(890), K*(1430) and A2(1320), A2(2040), respectively. Production cross sections, t distributions, and decay-angular distributions are studied. Isoscalar natural-parity exchange is dominant. The energy dependence of the K* and A2 resonance production between 10 and 175 GeV/c is well described by a Regge-pole model. Our data on A2 corrects that in an earlier paper.
No description provided.
No description provided.
No description provided.
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.
THE DIFFERENTIAL SCALING CROSS SECTION FOR NEUTRAL AND CHARGED D'S. DEFINITION OF Z IS 2*E(P=3)/SQRT(S).
The reaction π−p→K0K−p has been measured from 50 to 175 GeV/c. The production characteristics of the A2 have been analyzed. We find spin and t dependence similar to lower energies, but the cross section falls rapidly with energy. In a Regge description of π−p→A2−p our data imply a rather small Pomeron-exchange component.
No description provided.
RAW CROSS SECTION WITHIN MASS CUTS.
No description provided.
We have measured the cross section, the distribution of scattering angles, and the distribution of noncoplanarity angles for electron-positron elastic scattering at 5 GeV c. m. energy. An analysis based on 230 events with scattering angles between 50 and 130° yields a ratio of the experimental to theoretical quantum-electrodynamic cross section of 1.03 ± 0.09. The scattering-angle and noncoplanarity-angle distributions are also found to be in excellent agreement with the quantum-electrodynamic predictions.
No description provided.
We report the 24-GeV/c inclusive π− yield near θc.m.=90° for 0.5<~PT≲2.2 GeV/c. No high-PT excess is seen at this energy. In addition we have obtained the inclusive γ-ray yield from a measurement of low-mass e+e− pairs. This yield is compared with that expected from π0-, η-, and ω-meson decay, to provide limits on possible direct photon production.
No description provided.
The deep-inelastic scattering reaction νμN→μ−X has been studied using the deuterium-filled 15-foot bubble chamber at Fermilab. The data have been analyzed under the assumption of isospin invariance to extract x(uV-dV) for the proton, where xuV(x) and xdV(x) are the valence up- and down-quark momentum distributions, respectively. The results are compared with other data and with different theoretical fits. The ratio νn/νp as a function of x is also presented.
No description provided.
No description provided.
No description provided.
We report on measurements of the differential π±p cross section at pion energies Tπ=32.7, 45.1, and 68.6 MeV. The measurements, covering the angular range 25°≤θlab≤123°, have been carried out at the Paul-Scherrer-Institute (PSI) in Villigen, Switzerland, employing the magnet spectrometer LEPS. The absolute normalization of the π±p cross sections have been achieved by relating them to the electromagnetic cross sections of μ±12C scattering. The results are in agreement with those of our preceding measurements at Tπ=32.2 and 45.1 MeV insofar as they overlap with the region of the Coulomb nuclear interference investigated there. A comparison with the predictions of the Karlsruhe-Helsinki phase shift analysis KH80, which has formed the basis for the determination of the ‘‘experimental’’ σ term, reveals considerable deviations. These are most pronounced for the π+p cross sections at Tπ=32.7 and 45.1 MeV. Single energy partial wave fits result in S-wave contributions, which are about 1° lower in magnitude then those specified by the KH80 solution. The data at 68.6 MeV are in good agreement with the phase shift analysis.
Statistical and systematic errors are addet in quadrature.
Statistical and systematic errors are addet in quadrature.
Statistical and systematic errors are addet in quadrature.
The values of the pion nucleon (πN) σ term, as determined, on the one hand, from experimental pion nucleon scattering by means of dispersion relations and, on the other hand, from baryon masses by means of chiral perturbation theory, differ by 10 to 15 MeV. The origin of this discrepancy is not yet understood. If the difference between the two values is attributed to the scalar current of strange sea quark pairs within the proton, the contribution to the proton mass would be of the order of 120 MeV. The discrepancy may hint at either theoretical deficiencies or an inadequate πN database. In order to provide reliable experimental data we have measured angular distributions of elastic pion proton scattering at pion energies Tπ=32.2 and 44.6 MeV using the magnet spectrometer LEPS located at the Paul-Scherrer-Institute (PSI) in Villigen, Switzerland. From the data covering the region of the Coulomb nuclear interference, the real parts of the isospin-even forward scattering amplitude ReD+(t=0), have been determined as a function of energy. The results have been compared with the predictions of the Karlsruhe-Helsinki phase shift analysis KH80, revealing discrepancies most pronounced for the π+p data. The experimentally determined values for ReD+(t=0), however, support the KH80 prediction (which is based on πN data available in 1979).
Statistical and systematic errors are addet in quadrature.
Statistical and systematic errors are addet in quadrature.
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