Cross sections or upper limits are reported for 12 meson-baryon and two baryon-baryon reactions for an incident momentum of 9.9 GeV/c, near 90° c.m.: π±p→pπ±,pp±,π+°±,K+Σ±, (Λ0/Σ0)K0; K±p→pK±; p±p→pp. By studying the flavor dependence of the different reactions, we have been able to isolate the quark-interchange mechanism as dominant over gluon exchange and quark-antiquark annihilation.
No description provided.
No description provided.
The dissociation of virtual photons, $\gamma^{\star} p \to X p$, in events with a large rapidity gap between $X$ and the outgoing proton, as well as in events in which the leading proton was directly measured, has been studied with the ZEUS detector at HERA. The data cover photon virtualities $Q^2>2$ GeV$^2$ and $\gamma^{\star} p$ centre-of-mass energies $40<W<240$ GeV, with $M_X>2$ GeV, where $M_X$ is the mass of the hadronic final state, $X$. Leading protons were detected in the ZEUS leading proton spectrometer. The cross section is presented as a function of $t$, the squared four-momentum transfer at the proton vertex and $\Phi$, the azimuthal angle between the positron scattering plane and the proton scattering plane. It is also shown as a function of $Q^2$ and $\xpom$, the fraction of the proton's momentum carried by the diffractive exchange, as well as $\beta$, the Bjorken variable defined with respect to the diffractive exchange.
The differential cross section DSIG/DT for the LRG and the LPS data samples.
The fitted exponential slope of the T distribution as a function of X(NAME=POMERON).
The fitted exponential slope of the T distribution as a function of X(NAME=POMERON).
The reactionp→Δ(1236)\(\bar \Delta \)(1236) is studied at 7.23 GeV/c and at 12GeV/c in terms of the OPE model of Wolf. Good agreement between the model and experimental data is found for the mass andt distributions whereas for decay angular distributions the agreement is less satisfactory. A modified model, allowing for a spin orbit coupling, gives good agreement also for the angular distribution.
No description provided.
No description provided.
CROSS SECTION FOR -T < 0.14 GEV**2.
The differential cross-section for the elastic neutron-proton-scattering has been measured for neutron energies between 4 and 16 GeV and | t | from 0.3 to 1.3 (GeV/ c ) 2 . The results can be fitted by exp( A + Bt ), where B increases slightly with energy indicating shrinkage. The values of B for n−p scattering are in good agreement with the corresponding data for p−p scattering.
'1'. '2'. '3'. '4'.
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.
The differential cross sections for neutron-proton charge-exchange scattering have been measured with high statistics in the region of momentum transfer squared 0.002 < | t | ⩽ 0.400 (GeV/ c ) 2 and for incident neutron momenta 9 < p ⩽ 23 GeV/ c .
No description provided.
Forum