None
No description provided.
No description provided.
Differential cross sections for elastic π±−p scattering have been measured at lab momenta of 8 and 12 GeV/c in a momentum-transfer region corresponding to 1.2≤−t≤6 (GeV/c)2. Also, differential cross sections near 180° were measured for 4 and 8 GeV/c pions. At momentum transfers greater than −t=2 (GeV/c)2, the π−p cross sections drop much faster with increasing angle than the corresponding p−p cross sections. Also, in the region −t≃1.3 (GeV/c)2, there is structure in the π−p angular distribution but not in the p−p angular distribution. At −t≃3 (GeV/c)2, the drop in cross section appears to stop and from then on the angular distribution is consistent with isotropy. But in the angular region 170° to 180°, the cross sections have become much larger, and sharp backward peaks are observed. Information is given on the energy and charge dependences and widths of these backward peaks.
'1'. '2'.
'1'. '2'.
No description provided.
A total of 24 360 events having two charged particles in the final state from π−+p interactions at an incident π− momentum of 2.7 GeVc have been analyzed. The final states π−π+n and π−π0p are found to be dominated by rho-meson production, and in addition, significant N*(1238) production is seen. The partial cross sections for the dominant resonant channels are σ=(pρ−)=(1.3±0.2) mb, σ(nρ0)=(2.3±0.2) mb, and σ[π−N*+(→pπ0)]=(0.5±0.2) mb. The production of the ρ− and ρ0 and the decay of the ρ− agree very well with the predictions of an absorption-modified one-pion-exchange model. The production angular distributions of the ρ0 and ρ− follow an exponential of the form Ae+Bt. The results from a least-squares fit give B(ρ−)=9.32±0.08 (GeVc)−2, B(ρ0)=10.26±0.06 (GeVc)−2. A similar analysis for the elastic-scattering events gave B(el)=7.77±0.05 (GeVc)−2. The ρ0 decay distributions are asymmetric and they have been analyzed using a simple model which includes S−P-wave interference. No clear evidence is seen for a T=0, J=0 resonance at a mass near that of the ρ. The N*(1238) resonance production is found to be in agreement with the ρ-exchange model of Stodolsky and Sakurai. Indication of other resonance production with small cross section is seen, such as A1 and A2 production in the multiple missing neutral events. The masses and widths of the ρ0 and ρ− as a function of the four-momentum transfer squared to the nucleon have been determined.
No description provided.
Measurements of the ratio (R) of positron-proton and electron-proton elastic-scattering cross sections have been made, with the square of the four-momentum transfer (q2) equal to 0.20, 0.69, 0.73, 1.54, 2.44, 3.27, 3.79, and 5.00 (GeV/c)2. The measurements, after radiative corrections, are consistent with R=1, with standard errors ranging from ±0.016 to ±0.123. The results give limits for the size of the two-photon effects.
No description provided.
No description provided.
Elastic π±−p, K−−p, and p¯−p scattering cross sections have been measured using three different experimental arrangements covering the c.m. angular regions ∼20°-120°, ∼135°-169°, and ∼165°-180° at incident momenta from 6 to 17 GeV/c. In the region 130°-180°, only π±−p scattering was measured. In the angular region near 180°, the energy dependences and shapes of the π−p backward peaks were determined up to crossed-momentum transfers of u∼−2 (GeV/c)2. At all energies, the π+−p backward peak had a sharp dip at u=−0.13 (GeV/c)2, with no similar effect in the π−−p case. Nearly complete angular distributions of π−−p elastic scattering from 20° to 180° have been obtained at 6 and 10 GeV/c. These results at 6 and 10 GeV/c as well as at 8 GeV/c reveal a sharp dip in π−−p scattering at t=−3 (GeV/c)2. Several structures in the form of dips or shoulders were seen in the p¯−p angular distributions also, with less pronounced structure observed in K−−p scattering. At fixed momentum transfer, all cross sections when expressed as dσdt appear to be decreasing with increasing energy.
'1'. '2'. '3'. '4'.
No description provided.
No description provided.
Cross sections for π0 photoproduction from hydrogen in the backward direction have been measured for photon energies of 6, 8, 12, and 18 GeV. The range of momentum transfer covered in these measurements is −1 (GeVc)2<u<0(GeVc)2, dσdu is found to have a backward peak and decreases with energy as s−3.0±0.2. Photoproduction of η0 and ρ0 mesons has also been observed.
No description provided.
No description provided.
No description provided.
Cross sections for inelastic scattering of electrons from hydrogen were measured for incident energies from 7 to 17 GeV at scattering angles of 6° to 10° covering a range of squared four-momentum transfers up to 7.4 (GeV/c)2. For low center-of-mass energies of the final hadronic system the cross section shows prominent resonances at low momentum transfer and diminishes markedly at higher momentum transfer. For high excitations the cross section shows only a weak momentum-transfer dependence.
Axis error includes +- 0.0/0.0 contribution (?////FROM UNCERTAINTY IN ELECTRON-DETECTION EFFICIENCY).
Axis error includes +- 0.0/0.0 contribution (?////FROM UNCERTAINTY IN ELECTRON-DETECTION EFFICIENCY).
Axis error includes +- 0.0/0.0 contribution (?////FROM UNCERTAINTY IN ELECTRON-DETECTION EFFICIENCY).
None
No description provided.
No description provided.
No description provided.
None
No description provided.
Electron-proton elastic scattering cross sections have been measured at the Stanford Linear Accelerator Center at four-momentum transfers squared (q 2 ) of 1.0, 1.5, 2.0, 2.5and 3.75 (GeV/ c ) 2 . The angular distributions at q 2 = 2.5 and 3.75 (GeV/ c ) 2 are sufficient to provide values of the ratio G E / G M independent of the results from other laboratories. Our results are compatible with scaling, G E (q 2 ) = G M (q 2 )/ μ , within the experimental errors.
No description provided.
No description provided.
No description provided.
Cross sections for π − p→n π o at 5.9, 10.1 and 13.8 GeV/ c incident momentum are presented in the angular region from 180 o to u , the crossed four-momentum transfer squared, of −2(GeV) 2 and the energy dependence is discussed. The cross section for π − p→n η o integrated over the same angular region at 5.9 GeV/ c is also presented.
No description provided.
No description provided.
No description provided.
Compton-scattering cross sections from hydrogen (γp→γp) and from deuterium have been measured at four-momentum transfer t in the range 0.014<~−t<~0.17 GeV2 and photon energies of 8 and 16 GeV. Fits to our proton data of the form dσdt=AeBt give B≈7.8 GeV−2 and an intercept A which is in agreement with the optical point. Both coherent scattering from deuterons and incoherent scattering from neutrons and protons are seen from deuterium. A small difference between the neutron and proton cross sections is seen, indicating the presence of about a 3% isovector t-channel exchange amplitude in addition to the predominant isoscalar amplitude. The vector-dominance model predicts lower cross sections (by at least 20%) for both the hydrogen and deuterium cases.
Axis error includes +- 3/3 contribution (SUBTRACTIONS WERE MADE FOR THE REACTIONS GAMMA P --> PI0 N, ETA N, OMEGA N AND PI0 DELTA(1232)).
Axis error includes +- 3/3 contribution (SUBTRACTIONS WERE MADE FOR THE REACTIONS GAMMA P --> PI0 N, ETA N, OMEGA N AND PI0 DELTA(1232)).
Differential cross sections for electrons scattered inelastically from hydrogen have been measured at 18°, 26°, and 34°. The range of incident energy was 4.5 to 18 GeV, and the range of four-momentum transfer squared was 1.5 to 21 (GeVc)2. With the use of these data in conjunction with previously measured data at 6° and 10°, the contributions from the longitudinal and transverse components of the exchanged photon have been separately determined. The values of the ratio of the photoabsorption cross sections σSσT are found to lie in the range 0 to 0.5. The question of scaling of 2MpW1 and νW2 as a function of ω is discussed, and scaling is verified for a large kinematic range. Also, a new scaling variable which reduces to ω in the Bjorken limit is introduced which extends the scaling region. The behavior of σT and σS is also discussed as a function of ν and q2. Various weighted sum rules of νW2 are evaluated.
Axis error includes +- 0.0/0.0 contribution (0. TO 2.////DUE TO PION CONTAMINATION).
Axis error includes +- 0.0/0.0 contribution (0. TO 2.////DUE TO PION CONTAMINATION).
Axis error includes +- 0.0/0.0 contribution (0. TO 2.////DUE TO PION CONTAMINATION).
We have studied the proper time distribution of coherent π + π − decays from a 3 – 10 GeV/ c K L o beam incident on a one meter liquid hydrogen target using a wire spark chamber spectrometer in the 3 0 neutral beam at SLAC. We find ∣(ƒ(0) − ƒ (0))/k∣ = 0.43 ± 0.11 mb , φ(ƒ(0) − ƒ (0)) = -101 0 ± 42 0 .
No description provided.
Electron-proton elastic-scattering cross sections have been measured at the Stanford Linear Accelerator Center for four-momentum transfers squared q 2 from 1.0 to 25.0 (GeVc)2. The electric (GEp) and magnetic (GMp) form factors of the proton were not separated, since angular distributions were not measured at each q 2. However, values for GMp were derived assuming various relations between GEp and GMp. Several theoretical models for the behavior of the proton magnetic form factor at high values of q 2 are compared with the data.
No description provided.
No description provided.
No description provided.
We have measured the asymmetry parameter Σ=(σ∥−σ⊥)(σ∥+σ⊥) for the photoproduction of ϕ mesons with photons polarized parallel and perpendicular to the plane of decay for the reaction γp→ϕp→K+K−p. We find Σ=0.985±0.12 at a photon energy of 8.14 GeV and |t| of 0.2 (GeVc)2, consistent with pure diffraction production, or pure naturalparity Regge exchange.
No description provided.
We have extracted the strong interaction form factors from K o e3 and K o μ3 data of our previously reported K o L experiment in a manner which does not assume an explicit q 2 = ( p K − p π ) 2 dependence. We present the unparameterized form factors ƒ + (q 2 ) from the K o L → πeν and K o L → πμν modes and ƒ o (q 2 ) and ξ ( q 2 ) from the K o L → πμν data. A comparison of these unparameterized results is made with the results of the Dalitz plot analyses.
The conventional form factor f+ is studied.
We have measured angular distributions for single photoproduced π+ mesons at 4.0-, 5.0-, and 7.5-GeV incident photon energies and at lab angles from 11° to 66° with the Stanford Linear Accelerator Center 8-GeV spectrometer. Combined with previous Stanford Linear Accelerator Center results, this gives complete angular coverages for this range of energies. The data show the usual "t" and "u" diffraction peaks and a "central plateau" region dropping as S−7.3.
No description provided.
We have measured ρ0, ω (combined) and ϕ electroproduction over a range of virtual-photon four-momentum Q2 from 0.4 to 2.2 GeV2 and for photon energies ν from 2.7 to 8.6 GeV. We find that the slope of the t (momentum transfer) dependence of the ρ0 and ω forward peak decreases with increasing Q2 to less than half of the photoproduction slope.
The cross section for virtual photon are derived from E- P cross section bydividing on the virtual-photon flux factor.
Cross sections for inelastic scattering of electrons from hydrogen and deuterium were measured for incident energies from 4.5 to 18 GeV, at scattering angles of 18°, 26°, and 34°, and covering a range of squared four-momentum transfers up to 20 (GeVc)2. Neutron cross sections were extracted from the deuterium data using an impulse approximation. Comparisons with the proton measurements show significant differences between the neutron and proton cross sections.
Axis error includes +- 1/1 contribution (DUE TO ERRORS IN ABOVE CORRECTIONSFOR DEAD-TIME LOSSES, INEFFICIENCIES IN E- IDENTIFICATION).
The v and v nucleon total cross-sections have been determined as a function of energy using a sample of 2500 v and 950 v event. The results are compared with predictions of scaling and charge symmetry hypotheses.
Measured charged current total cross section.
Measured charged current total cross section.
We have measured ep, eπ+, and eπ− coincidences for scattered electrons in the range Q2=0.4 to 2.2 GeV2 and W=2 to 4 GeV. We find (a) that vector-meson production decreases with Q2 more rapidly than does the total virtual-photon-plus-proton cross section, more rapidly even than the prediction of simple vector dominance, (b) that the slope of the t distribution in ρ and ω production becomes flatter with increasing Q2 and seems to be at least approximately a function of the single variable xρ=(Q2+mρ2)2Mν, (c) that the fraction of final states containing a proton decreases with increasing Q2, (d) that in the central region of longitudinal momenta the inclusive π+ yield seems to increase relative to the π− yield as Q2 increases, and (e) that the average transverse momentum of π− is greater than of π+ in the central region of longitudinal momenta.
No description provided.
The data with (C=Q=RHO+OMEGA) are obtained by excluding the contribution from RHO and OMEGA production.
No description provided.
Differential cross sections for electron scattering from hydrogen and deuterium in the deep-inelastic region show that the neutron cross section is significantly smaller than the proton cross section over a large part of the kinematic region studied. Although νW2d differs in magnitude from νW2p, it exhibits a similar scaling behavior.
No description provided.
No description provided.
No description provided.
We report measurements of the ratio of the deep-inelastic electron-neutron to electron-proton differential cross sections in the threshold ( ω <3) region. The ratio was found to scale and to decrease monotically with decreasing ω . No violation of the quark model lower bound of 0.25 was observed in the ratio.
DATA ARE AVERAGED THROUG AVAILABLE KINEMATIC REGION.
None
ONE EVENT SEEN - PROBABLY AN ANTIPROTON.
The reaction π−p→X−p, X−→ηπ−, η→γγ has been studied in an optical spark-chamber experiment at the Argonne ZGS (Zero Gradient Synchrotron) at a beam momentum of 6.0 GeV/c and with 0.27≤|t|≤0.42 (GeV/c)2. The ηπ mass spectrum contains about 1400 events in the mass range 0.80<M(ηπ)<1.55 GeV/c2, and is dominated by approximately 1000 events of the type A2−→ηπ−. No structure is discernible within the A2 mass spectrum for an experimental resolution of 7.1 MeV/c2 [16.7 MeV/c2 FWHM (full width at half maximum)]. A single D-wave Breit-Wigner distribution fits the data with a high confidence level, yielding for the A2 the parameters M0=1.323±0.003 GeV/c2 and Γ0=0.108±0.009 GeV/c2. The angular distribution of the decay A2−→ηπ− is analyzed and the resultant density matrix elements have the values ρ11=0.45±0.02, ρ1−1=0.45±0.04, and ρ00=0.09±0.04. All other elements are consistent with zero. Finally, the missing-mass spectrum in the region of the A2 is presented. A signal of 230 events above background per 5-MeV/c2 interval is observed at the A2 peak, with a signal to background ratio of greater than 1:1. A single D-wave Breit-Wigner distribution together with a quadratic background fits the data well, with the parameters for the A2 being M0=1.324±0.003 GeV/c2 and Γ0=0.104±0.009 GeV/c2. Both A2 mass spectra are incompatible with the dipole shape.
No description provided.
THIS FIT ASSUMES ALL OTHER DENSITY MATRIX ELEMENTS (RHO(2M) AND RE(RHO(10))) ARE ZERO SINCE THEY ARE QUITE CONSISTENT WITH ZERO IN A FULL FIT. QUOTED ERRORS INCLUDE SYSTEMATIC ERRORS, WHILE STATISTICAL FITTING ERRORS ARE SHOWN SEPARATELY.
We have done an inclusive study of ϱ 0 production in π − p interactions at 15 GeV/ c . Evidence for two different production mechanisms, in addition to the known quasi two-body processes, is presented: production of ϱ 0 's in the central region of rapidity similar to the “pionization” region seen in the inclusive studies of pions; and forward production in the beam dissociation region of rapidity. Cross sections and rapidity distributions for the ϱ 0 are given inclusively and by topology, and the results are compared with similar studies at other energies and with other incident particles. Results are also presented for the semi-inclusive reaction π − p → p ϱ 0 + X − and the exclusive final state p π − ϱ 0 .
No description provided.
None
No description provided.
No description provided.
No description provided.
The reaction π − p → ω n has been studied at 8 and 12 GeV / c incident momenta with the CERN Omega spectrometer using a neutron time of flight trigger. The differential cross sections and the ω-decay density matrix elements are presented as functions of the momentum transfer squared − t in the range of 0.02 to 0.80 GeV 2 . The data are used to evaluate the intercept and slope of both the natural and unnatural parity exchange trajectories. Regge exchange amplitude factorisation tests involving the reaction π N → ω N are investigated.
No description provided.
'FIT'.
'FIT'.
We report measurements of the invariant cross section in the forward hemisphere for inclusive photoproduction of π±, K±, p, and p¯ from hydrogen and deuterium with an incident photon energy of 18 GeV. A small amount of data was also taken at incident energies of 9 and 13 GeV. The measurements were made using the SLAC 20-GeV/c spectrometer, and a bremsstrahlung-subtraction technique was used to obtain the cross sections at the specified incident energy. The data are compared with those from lower-energy experiments and interpreted within the context of the Mueller-Regge model and the constituent-interchange model.
No description provided.
No description provided.
No description provided.
In view of the possible production of heavy leptons or charmed states in e+e− collisions, we searched for anomalous muons with momenta pμ≳1 GeV/c. The inclusive cross section for nch>~3 has an upper limit of 96 pb (assuming isotropy). For nch=2 and noncoplanarity > 20°, an excess of muonic events is observed, corresponding to (dσdΩ)|90°=23−9+12 pb/sr; the probability that known processes produce the observed events is 2×10−4.
No description provided.
Exclusive photoproduction cross sections have been measured for the processes γp→π+n, γp→π0p, γp→π−Δ++, γp→ρ0p, γp→K+Λ, and γp→K+Σ0 at large t and u values at several energies for each process between 4 and 7.5 GeV. These measurements taken together with past data taken at small values of t and u provide complete angular distributions. The data show the usual small t and u peaks and a central region in which the cross section decreases approximately as s−7. The results are discussed within the context of parton or constituent models.
No description provided.
No description provided.
No description provided.
The properties of the diffractive peak observed in the mass spectra of systems recoiling against observed high-momentum protons emerging from pp collisions at the CERN ISR have been investigated. The cross sections in this peak have been found to have a steep t dependence which flattens out as | t | increases. The high mass side of the peak varies approximately as 1/ M 2 (where M is the missing mass of the recoiling system) and scales well in terms of the variable M 2 / s . The position of the maximum has been observed to move to lower values of M 2 / s as the kinematic boundary of this variable decreases with increasing s . The measured cross sections, integrated up to M 2 / s =0.05, rise by (15±5)% over the s range 549 to 1464 GeV 2 .
No description provided.
No description provided.
No description provided.
The production of the f 0 (1270) has been studied in the reaction π − p → π + π − n at 12 and 15 GeV/ c in the momentum transfer range 0.02 to 0.80 GeV 2 . Differential and total cross sections for the reaction π − p → f 0 n have been determined. The f 0 decay density matrix elements have been evaluated requiring all the matrix eigenvalues to be non-negative. The relative unnatural and natural parity exchange contributions to the f 0 production have been studied. The results are compared with a Regge exchange model formulated in terms of the pion and A 2 exchanges including cut contributions.
No description provided.
No description provided.
No description provided.
We have measured the electromagnetic form factor of the charged pion by direct scattering of 100-GeV/c π− from stationary electrons in a liquid-hydrogen target at Fermilab. The deviations from the pointlike pion-scattering cross section may be characterized by a root-mean-square charge radius for the pion of 〈rπ2〉12=0.56±0.04 F.
No description provided.
We present extracted data for the pure I = 1 π 0 Λ (1520) channel from the reaction K − p → K − p π 0 at 11 incident momenta between 0.96 and 1.355 GeV/ c (1775 to 1960 MeV c.m. energy). A partial-wave analysis of this channel has been carried out over a broad c.m. energy range from 1710 to 2170 MeV using data at 27 momenta from this and earlier experiments. The 5 2 − Σ(1775) and built7 2 + Σ(2030) resonances are found to decay strongly to this channel. Amplitudes are also obtained for less dominant and less well-established resonances.
THESE CROSS SECTIONS ARE GIVEN IN TABLE 1B OF W. CAMERON ET AL., NP B146, 327 (1978).
LEGENDRE POLYNOMIAL COEFFICIENTS FOR ANGULAR DISTRIBUTION OF CROSS SECTION.
LEGENDRE POLYNOMIAL COEFFICIENTS FOR ANGULAR DISTRIBUTION OF DENSITY MATRIX ELEMENT RHO(MM=33,XYZ=SH).
The charged-current cross sections for neutrinos and antineutrinos on nucleons in the energy range 20–200 GeV are given. Taken in conjunction with the previous Gargamelle results, they show that σ E is almost constant with energy for antineutrinos, and falls with energy for neutrinos. The value of 〈q 2 〉 E decreases with energy for both neutrinos and antineutrinos, and these deviations from exact Bjorken scaling are consistent with those observed in electron and muon inelastic scattering. We find no evidence for new heavy quark states with right-handed coupling.
Measured charged current total cross section.
Measured charged current total cross section.
Data on the reaction π − p → π + π − π 0 have been taken at 12 and 15 GeV/ c with the CERN Omega multiparticle spectrometer. In a 3-pion partial-wave analysis strong production of A 2 0 (1310) and ω ∗ (1675) is observed. Total and differential cross sections are determined and density matrix elements presented as a function of t in the t - and s -channel frames. The energy dependence of A 2 0 production is studied, and a comparison of ω(780), A 2 0 (1310) and ω ∗ (1675) production is made.
No description provided.
No description provided.
No description provided.
Final states produced by charged baryon exchange in π − p interactions at 12 GeV/ c laboratory momentum have been studied. Forward neutrons with momenta determined by a calorimeter to be greater than 8.5 ± 1.4 GeV/ c triggered the SLAC 40-inch hydrogen bubble chamber which operated at a 10 Hz expansion rate. We report data on the reactions π − p→n π − π + , π − p→n π − π + π 0 , and π − p→n π − π − π + π + . In π − n π − p→n π + , production of ϱ and f mesons is observed. Differential cross sections are derived and compared with data at lower incident momentum and with theoretical models. In π − p→n π − π + π 0 , ω production is observed with a differential cross section having a deep near u ′= 0.2 (GeV/ c ) 2 . In π − p→n π − π − π + π + , Δ − , ϱ and f production is observed . The observed mass distributions appear to indicate the production of wide resonaces decaying into ϱππ. Some evidence for ϱ-ω interference is also observed.
No description provided.
No description provided.
CORRECTED FOR BACKGROUND.
We present results on charged multiplicity nch=2 and nch>2 muon events produced in e+e− collisions with 〈s12〉=7.3 GeV at 90° to the beams. The background-subtracted inclusive cross section for the nch=2 events is 10.2±5.4 pb/sr, in agreement with the expected contribution from the heavy lepton τ. The cross section for the nch>2 events is 19.0±6.5 pb/sr whereas we expect only 2.9 pb/sr from the τ, indicating that we may be seeing the weak decays of charmed mesons.
No description provided.
No description provided.
None
No description provided.
INTEGRATED CROSS SECTION ESTIMATED USING MODEL.
The production of the ω meson by virtual photons has been measured as a function of Q2 and W. The ratio of ω production to ρ0 production is independent of Q2 in contrast to indications at lower values of W.
No description provided.
The cross section for production of ρ0 mesons has been measured in the reaction e+p→e+p+π++π−. The cross section is presented as a function of W, the c.m. energy of the virtual-photon-proton system, and -Q2, the square of the virtual-photon mass. The vector-dominance model is not able to describe the dependence of the cross section on the parameters Q2 and W. The slope parameter B describing the scattering of the proton exhibits a significant variation with Q2.
No description provided.
New data on differential cross sections and polarisation are presented at nine incident momenta up to 1334 MeV/ c . An energy-dependent phase-shift analysis has been made and resonance parameters are given.
No description provided.
No description provided.
No description provided.
We present results for the differential cross sections of neutrinos and antineutrinos on nucleons in the energy range E = 2−200 GeV, from the BEBC and Gargamelle experiments. The structure functions F 2 , 2 χF 1 and χF 3 have been evaluated as a function of χ and q 2 . Deviations are observed from Bjorken scaling, which are very similar to those found in electron and muon inelastic scattering. For the Callan-Gross ratio, we find 2χF 1 F 2 = 0.80 ± 0.12 and the corresponding value for 〈R〉 = 〈 σ S σ T 〉 = 0.15 ± 0.10 . Our results are consistent with the Gross-Llewellyn-Smith sum rule; we measure ⩾2.5 ± 0.5 valence quarks per nucleon. Quark and antiquark distributions are given. The Nachtmann moments of F 2 and χF 3 are quantitatively consistent with the predictions from QCD. The value of the strong interaction parameter is λ = 0.74 ± 0.05 GeV without corrections, and 0.66 ± 0.05 GeV including α S 2 corrections. The moments of the gluon distribution are found to be positive and indicate an χ distribution of gluons which is comparable with that of the valence quarks.
No description provided.
No description provided.
We report on inclusive hadron production in e+e− annihilation at 〈s〉=53 GeV2, using a small solid-angle magnetic spectrometer with good particle identification at 90° to the beams at SPEAR II. The cross sections of π± and K± when compared with data at s=23 GeV2 exhibit scaling in (sβ)dσdx with x=2Es12. The invariant cross section depends on the momentum as p−4.
No description provided.
No description provided.
No description provided.
We have observed the D(1285), E(1420) and δ(975) mesons produced in 12 and 15 GeV/ c π − p interactions at the CERN Omega Spectrometer. Production cross sections and decay branching ratios are presented. Analysis of the decay D(1285) → δ (975) π favours a spin-parity assignment of 1 + .
No description provided.
CORRECTED FOR DECAY MODES OTHER THAN <ETA PI+ PI-> AND FOR THE UNOBSERVED PARTS OF THE T-DISTRIBUTION.
No description provided.
New data are presented on the differential cross section and polarisation for the reaction π − p → K 0 Σ 0 at six incident momenta from threshold up to 1334 MeV/ c .
No description provided.
No description provided.
No description provided.
Inclusive momentum and energy spectra of neutral and charged D-mesons produced in e + e − annihilation at energies near 7 GeV are presented. The slope of the energy spectrum is similar to the charged pion spectrum at the same energy. The inclusive cross section σ(e + e − → D or D + anything) at 7 GeV is 4.8±1.3 nb.
No description provided.
No description provided.
SCALING VARIABLE IS X(P=3,DEF=2*E(P=3)/SQRT(S)) > 0.54.
We have carried out an experimental study of the neutron and proton deep-inelastic electromagnetic structure functions. The structure functions were extracted from electron-proton and electron-deuteron differential cross sections measured in three experiments spanning the angles 6°, 10°, 15°, 18°, 19°, 26°, and 34°. We report primarily on the large-angle (15°-34°) measurements. Neutron cross sections were extracted from the deuteron data using an impulse approximation. Our results are consistent with the hypothesis that the nucleon is composed of pointlike constituents. The variation of the cross section with angle suggests that the hypothetical constituents have spin ½. The data for σnσp, the ratio of the neutron and proton differential cross sections, are in the range 0.25 to 1.0, and are within the limits imposed by the quark model. Detailed studies of the structure functions were made for a range of the scaling variable ω from ω=1.3 to ω=10.0, and for a range of invariant four-momentum transfer Q2 from 1.0 to 20.0 GeV2. These studies indicate that the structure functions approximately scale in the variable ω, although significant deviations from scaling in ω are apparent in the region 1.3<ω<3.3. These deviations from scaling are in the same direction and of similar magnitude for both neutron and proton. The interpretation of the data in terms of various theoretical models is discussed.
No description provided.
No description provided.
No description provided.
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