Inclusive ϕ-meson production has been measured for 100 GeV/cK−,\(\bar p\) andp incident on a Be target. Differential cross sectionsdσ/dxF anddσ/dp⊥2 are presented in the interval 0.075<xF<0.225 and 0<p⊥<1 GeV/c respectively. The shape of thedσ/dxF distributions agrees with predictions from a quark fusion model. Comparison with cross sections measured on a hydrogen target in the samexF andp⊥ range suggest a linearA-dependence fromA=1 toA=9.
No description provided.
We have measured the differential and total cross sections ofD meson production in 200 GeV π−-beryllium interactions, using a sample of 48 fully reconstructed and nearly background-freeD mesons in the decay channelsK∓π±,K∓π±π± andK∓π∓π±π±. A single electron trigger has been used to select events containing a pair of charmed particles. A vertex telescope of 6 silison microstrip detectors allowed the reconstruction of tracks of charged secondaries and the reconstruction of primary and decay vertices with high precision. The ratio of branching fractions for\(\mathop {D^0 }\limits^{( - )}\to K^ \mp\pi ^ \pm\) to\(\mathop {D^0 }\limits^{( - )}\to K^ \mp\pi ^ \mp\pi ^ \pm\pi ^ \pm\), and an upper limit for\(D^0- \bar D^0 \) mixing are presented.
'leading' D-mesons, i.e. D-mesons, containing quarks, from PI- beam. Also AD0-mesons from. D*- decays.
'non-leading' D-mesons.
No description provided.
Inclusive ϕ meson production has been measured for 100 GeV/c and 200 GeV/c incident π−,\(\bar p\) andK−, and for 120 GeV/c and 200 GeV/c incident π+,p andK+, using a Be target. A total of 630,000 ϕ mesons has been recorded in the kinematic range 0<xF<0.4. Presented are the differential cross sectionsdσ/dxF anddσ/dpT2. The longitudinal momentum distributions show that the strange valence quarks of the incidentK mesons play an important role in ϕ meson production, even at smallxF. The decay angular distribution of the ϕ meson is evaluated in the Gottfried-Jackson frame and is expressed in the elements of the density matrix. There is a small but significant cos2θGJ dependence for smallpT, which decreases for increasingpT.
Note that the data is plotted in fig. 5 a factor 5 too large. The numbers here are correct.
Note that the data is plotted in fig 5 a factor of 5 too large. The numbers here are correct.
Note that the data is plotted in fig. 5 a factor of 5 too large. CT = The numbers here are correct.
The reactions\(K^ -Be \to {}^(\bar K^) *^0 (890)X,\pi ^ -Be \to {}^(\bar K^) *^0 (890)X\), have been studied in a 175 GeV unseparated hadron beam in the kinematic range 0<xF<1.0 andpT2<5 GeV2. Integrated cross-sections and the dependence of the cross-sections on the longitudinal and transverse momentum are presented, together with quark counting rules predictions. The nuclear dependence ofK− fragmentation intoK*0(890) with respect to Feynmanx is investigated from hydrogen to beryllium.
No description provided.
No description provided.
No description provided.
A search has been made for the hadronic production of charmed baryons and mesons with a large aperture forward magnetic spectrometer using 150 GeV protons originating from the CERN-SPS. A prompt electron trigger was used as a signature for charm. Upper limits at 90% confidence level have been obtained for the production of Λ c + D 0 , D 0 D + and D − : σ(Λ c ) ⩽ 8 μ b , σ( D 0 ) ⩽ 64 μ b , σ( D 0 ) < 37 μ b , σ( D + ) ⩽ 51 μ b and σ( D − ) ⩽ 49 μ b per nucleon, assuming linear A dependence. Systematic errors due to uncertainties in branching ratios and to model dependence of the acceptance calculation are discussed.
No description provided.
An experiment has been performed to search for associated hadronic production of charmed mesons, using a large-aperture forward magnetic spectrometer setup in a π − beam at the CERN SPS. A prompt electron trigger was used to select events containing a pair by charmed particles. D mesons have been identified by reconstruction of hadronic decay modes such as Kπ, Kππ. Data have been taken at 120, 175, and 200 GeV, The D D cross section measured at 175 200 GeV is σ( D D ) = (48 ± 15) μ b with a systematic uncertainty of ±50%. The energy dependence of the cross section is measured to be σ( D D ) [120 GeV )/σ( D D [175/200 GeV ] = 0.62 ± 0.34 .
No description provided.
No description provided.
We present single inclusive π±, π0 andK± spectra in the forward fragmentation region (x>0.2,pT<1.5 GeV/c) as well as correlations between two charged particles. The data were recorded in an unseparated negative hadron beam at the CERN SPS using a large acceptance forward spectrometer. Our maasurements are compared in detail with several models which emphasise the role of the beam valence quarks in this production process. The connection to measurements at largepT is also investigated.
ERRORS INCLUDE SYSTEMATIC ERRORS BUT NOT OVERALL NORMALISATION UNCERTAINTY OF 8PCT.
ERRORS INCLUDE SYSTEMATIC ERRORS BUT NOT OVERALL NORMALISATION UNCERTAINTY OF 8PCT.
ERRORS INCLUDE SYSTEMATIC ERRORS BUT NOT OVERALL NORMALISATION UNCERTAINTY OF 8PCT.
We present an analysis of theKs0Ks0 system produced in the reaction π−p→Ks0Ks0n at 63 GeV based on ∼700 events in the kinematical region of |t|<0.5 GeV2. We concentrate on masses between 1,200 and 1,600 MeV where a double maximum structure is observed. Performing an amplitude analysis in this mass interval we find thatS,D0 andD+ waves contribute to the mass spectrum at approximately equal strength. The peaks are attributed to spin 2 waves. However, we failed to explained them by interferingf(1270),A2(1310) andf′(1520) resonances alone. While the first peak can be associated withf(1270)−A2(1310) production, an additional tensor meson is needed with mass of ∼1410 MeV and a narrow width for a description of the second one. The analysis as well as the energy dependence deduced from some publishedKs0Ks0 mass spectra suggests this object to be dominantly produced by a natural parity exchange. Because the 2++\(q\bar q\) nonet is already complete the nature of the new tensor meson is an open question.
No description provided.
In partial wave analyses of the ( π − π − π + ) system, substantial shape changes of the 1 + S ( ϱπ ) intensity as a function of t , and relative phase changes of ≈ 90°, provide compelling evidence for a resonant A 1 of mass ≈ 1280 MeV and width ≈ 300 MeV.
No description provided.
The J PC = 2 −+ partial wave intensities and their large phase changes prove the resonant nature of the A 3 meson (mass ≈ 1670 MeV, width ≈ 210 MeV). The decay modes are f 0 π , ϱ 0 π , and ϵ 0 π . Evidence is found for a further 2 − enhancement.
No description provided.
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