The results of the experiment searching for quarks with charge − 1 3 and 2 3 produced by 70 GeV protons on an aluminium target at zero angle are reported. For the selection of quarks the system of spectrometric scintillation counters, time-of-flight spectrometer, gas Cerenkov threshold counter and magnetic spectrometer with spark chambers were used. In the range of masses available at the IHEP accelerator, quarks were not found. The upper limit estimation of the differential cross-section for quark production with mass ⩽ 5 GeV /c 2− and charge −1 3 is 7×10 −38 cm 2 / ster GeV /c (with 90% confidence level). The total cross-section for quark production with charge −1 3 and mass 4.5–5 GeV /c 2 does not exceed 3×10 −39 cm 2 .
No description provided.
No description provided.
3 H̃e nuclei were observed in the negative beam, produced by 70 GeV protons on an Al target. Five 3 H̃e have been identified among 2.4 · 10 11 particles that passed through the apparatus. Scintillation and Čerenkov counters were used to measure the electrical charge and velocity of particles. The mass of 3 H̃e is found to be M 3 H ̃ e = (1.00 ± 0.03)3m p , the charge is z = (0.99 ± 0.03)2 e . The ratio of differential production cross sections of 3 H ̃ e (P = 20 GeV /c) and π − (P = 10 GeV/c ) equals 2 · 10 −11 . This corresponds to antihelium −3 production cross section d 2 σ 3 H ̃ e / d Ω d P = 2.0 · 10 −35 cm 2 / sr · GeV /c per Al nuclei and 2.2 · 10 −36 cm 2 sr · GeV/ c per nucleon.
No description provided.
No description provided.
The differential cross sections of the elastic backward scattering reaction π − n→n π − has been measured at 23 and 40 GeV/ c in the u -interval −0.07 ⩽ u ⩽ 0.01 (GeV/ c ) 2 .
No description provided.
No description provided.
We report our first measurements of the polarization in the elastic scattering of negative pions from polarized protons at an incident pion momentum of 40 GeV/ c . The momentum-transfer region covered was 0.08 < | t | < 1.3 (GeV/ c ) 2 . The angular distribution of the polarization exhibits a first minimum of ∼ − 5% and the well-known zero around t ≈ − 0.6 (GeV/ c ) 2 . The energy variation of the first minimum (at around t = − 0.2) may be expressed in a simple form, P avr = −(0.48±0.06) s −0.52±0.05 .
No description provided.
None
No description provided.
From measurements of proton-proton elastic scattering at very small momentum transfers where the nuclear and Coulomb amplitudes interfere, we have deduced values of ρ, the ratio of the real to the imaginary forward nuclear amplitude, for energies from 50 to 400 GeV. We find that ρ increases from -0.157 ± 0.012 at 51.5 GeV to +0.039 ± 0.012 at 393 GeV, crossing zero at 280 ± 60 GeV.
No description provided.
Cross sections of 27 radionuclides formed by the interaction of 300-GeV protons with silver were determined on the assumption that the cross section of the reaction Al27(p, 3pn) remains the same as at 10-30 GeV. The results are compared with the corresponding values obtained at 11.5 GeV. The average value of the ratio σ300σ11.5 for all products ranging from Be7 to Ag106m is 0.91±0.07 and is independent of mass number.
No description provided.
SIG(C=11.5) means the cross section for 11.5 GeV Plab, obtained in previousexperiment.
The reaction K − p → X K − p has been measured at 25 and 40 GeV/ c at the Serpukhov accelerator using the CERN-IHEP boson spectrometer. At both energies we observe production of the resonances K ∗− (890) and K ∗− (1420) in the channels K ∗− → K 0 π − and K − π 0 ; the momentum dependence of their production cross sections is found to be σ[ K ∗− (890)] ∞ p inc −1.48±0.04 and σ [ K ∗− (1420)] ∞ p inc −0.8±0.2 .
No description provided.
No description provided.
No description provided.
Elastic diffraction scattering of π − , K − and p on protons has been measured at 25 and 40 GeV/c at the Serpukhov Proton Accelerator. Differential elastic cross sections and diffraction slopes are presented in the momentum-transfer interval 0.07–0.80 (GeV/ c ) 2 and compared with existing data at lower energies.
No description provided.
No description provided.
No description provided.
A study has been made of the individual channels that contribute to the reaction K − p → Λ 0 + neutrals in the K − momentum range from 525 to 820 MeV/ c . Total cross sections are presented for the K − p → Λ 0 η 0 , Σ 0 Σ 0 π 0 , Λ 0 π 0 , Σ 0 π 0 and Σ 0 π 0 π 0 channels and differential cross sections for K − p → Λ 0 π 0 . The data were obtained in a heavy liquid bubble chamber experiment with an average gamma detection efficiency of 70%. Only events with all decay gammas detected were used for analysis. This is the first of a series of papers on this subject and presents the experimental technique in detail.
No description provided.
Forum