The differential cross-section for elastic charge-exchange scattering of neutrons on protons has been measured at 8 GeV/c over forward laboratory scattering angles (0÷90) mrad (square of four-momentum transfer 0<−t<0.5 (GeV/c)2). The method utilized acoustic spark chambers and about 1900 elastic-scattering events were analysed. A value of (dσ/dΩ)lab=(20±6) mb/sr (dσ/dt=(0.93±0.28) mb/(GeV/c)2) was obtained for the forward differential cross-section and an estimated (0.06±0.03) mb for the elastic charge exchange cross-section. Both cross-sections show the decreased values expected from Pomeranchuk’s second theorem (1) when compared with results at lower energies (2). Further comparison shows that the narrow forward peak in the distribution of dσ/dt previously observed for −t<0.05, is still present at 8 GeV/c, varying in shape only slowly, if at all, with energy. For −t>0.1 however, energy dependence is apparent. The results also suggest that the interaction is spin-dependent and/or that the real parts of the scattering amplitudes in the isospin states 0 and 1 are different. Comparisons with the theoretical predictions show good agreement with the value of forward cross-section given by the Regge pole approach ofAhmadzadeh (3). The model ofRingland andPhillips (4) for single-pion exchange with absorption agrees with our results for −t<0.01 but a predicted secondary peak at −t∼0.08 is not observed.
No description provided.
None
'1'. '2'.
No description provided.
No description provided.
The np elastic differential cross section has been measured for incident neutron momenta 100–400 GeV/ c in the | t | range 6 · 10 −6 − 5 · 10 −1 (GeV/ c ) 2 . The np data of this experiment provide a first direct measurement of the hadronic amplitude for | t | < 10 −2 (GeV/ c ) 2 , which is consistent with the extrapolations from higher | t | values. Our data for | t | < 10 −4 (GeV/ c ) 2 are consistent with a rise which can be attributed to Schwinger scattering, caused by the interaction of the neutron magnetic moment with the proton.
No description provided.
No description provided.
No description provided.
We report the results of an experiment which measured n-p elastic scattering differential cross sections over a range in -t from 0.15 to ~ 3.6 (Gev/c)2 for incident neutron momenta from 70 to 400 GeV/c. We find the logarithmic slope parameter, evaluated at -t = 0.2 (GeV/c)2, to be consistent with existing proton-proton parameterizations. The data exhibit a dip in the cross section near -t 1.4 (Gev/c)2 for incident neutron momenta above 200 Gev/c. For neutron momenta less than 280 GeV/c, the neutron-proton cross sections are found to be higher than existing proton-proton data in the range 0.7 ~ -t ~ 1.3 (Gev/c)2 which is in contradic- tion to most Regge predictions.
No description provided.
No description provided.
No description provided.
Measurements of the total cross section have been performed at the ISR with c.m. energies between 23.5 GeV and 62.5 GeV. Two independent experimental methods have been applied, a measurement of total interaction rate and of small angle elastic scattering. Both experiments give consistent results showing that the total cross section increases by (11.8±1.5) % over the ISR energy range. This experiment has also measured the slope of the forward diffraction peak in elastic scattering at small momentum transfer. The elastic cross section shows the same relative rise as the total cross section, and the ratio λ of elastic to total cross section approaches a constant value of λ =0.178±0.003.
.
TOTAL ELASTIC CROSS SECTION FROM INTEGRATING THE PARAMETRIZED DIFFERENTIAL CROSS SECTION, USING ALL OPTICAL POINT DATA AND AT LARGE -T RESULTS OF OTHER EXPERIMENTS.
.
The differential cross section for neutron-proton elastic scattering was measured in the diffraction region with incident-neutron momenta between 8 and 30 GeV/c. The experiment was a spark-chamber-counter experiment, conducted at the alternating-gradient synchrotron. Results are presented and compared with currently available lower energy np data and comparable energy pp data.
No description provided.
This paper describes a measurement of the neutron-proton differential cross section made at the Argonne National Laboratory Zero Gradient Synchrotron. The differential cross sections, based on about 470 000 events, are presented for 8 different momentum ranges between 4.5 and 12.5 GeV/ c . The data extend from small angles out to about 145° in the c.m.s., corresponding to 0.14 < − t ⪅ 19 (GeV/ c ) 2 at the highest energies. These results in conjunction with previous np charge-exchange data provide almost complete angular distributions in this momentum range. A detailed comparison of the data with existing pp data and with theoretical predictions is made.
No description provided.
Direct measurements were made of neutron-proton elastic scattering differential cross sections at high energies. A neutron beam with a continuous momentum spectrum between 1.2 and 6.7 GeV/c was scattered off a liquid hydrogen target, and spark chambers were used to determine the neutron scattering angle and, in a proton spectrometer, to measure the momentum and scattering angle of the recoil proton. Differential cross sections are presented over the incident neutron momentum range in intervals of the order of 0.5-GeV/c wide. The cross sections have an exponential peak in the forward direction and then flatten and become isotropic about the 90° c.m. scattering angle. At larger angles, the cross sections again rise towards the expected charge-exchange peak, which was not within the range of this experiment. There is little evidence of any other structure in the cross section. Values are presented for the slope of the diffraction peak, and comparisons are made between these slopes, and the 90° c.m. cross sections, for pp and np elastic scattering. The results presented here differ from those previously reported because of an error in a Monte Carlo calculation and in the availability of improved data on the real part of the np elastic scattering amplitude. At 5 GeV/c, a direct comparison of pp and np data allows the I=0 differential cross section to be extracted. The np data have been fitted in powers of cosθc.m. for |cosθc.m.|<0.8 for each energy range.
No description provided.
No description provided.
No description provided.
n−p elastic differential cross sections in the charge-exchange region have been measured for incident neutron momenta between 600 and 2000 MeV/c. The momentum of neutrons incident on a liquid-H2 target was determined by a measurement of flight time over a 32.9-m flight path. The momentum and scattering angles of the recoil proton were measured by a wire-spark-chamber magnetic spectrometer. Approximately 450 000 elastic events were detected for proton laboratory angles between 0° and 62°. Differential cross sections are presented at 16 energies. An absolute normalization of the cross sections was achieved by measuring the incident neutron flux with a detector whose efficiency was determined experimentally.
No description provided.
No description provided.
No description provided.
21 differential cross section measurements of the np → pn charge-exchange reaction have been carried out at the synchrotron Saturne (Saclay), for incident neutron momenta between 1 and 2 GeV/ c and in the squared four-momentum transfer range 0 ⩽ −t ⩽ 0.4 (GeV/ c ) 2 . The π exchange peak is seen at all the incident momenta. The s dependence of the very forward slope of this peak shows weak structures near the threshold of inelastic channels.
No description provided.
No description provided.
No description provided.
Forum