The differential cross sections of the charge exchange reaction
d
p
→
(
p
p
)
n
has been measured at 1.75 GeV/c per nucleon for small transferred momenta using the one arm magnetic spectrometer ...STRELA at the Nuclotron accelerator in JINR Dubna. The ratio of the differential cross section of the charge exchange reaction
d
p
→
(
p
p
)
n
to that of the
n
p
→
p
n
elementary process is discussed in order to estimate the spin-dependent part of the
n
p
→
p
n
charge exchange amplitude. The
n
p
→
p
n
amplitude turned out to be predominantly spin-dependent.
Abstract
The analyzing powers for neutron charge exchange
nA
→
pX
reactions on nuclei have been measured on C, CH2 and Cu targets at incident neutron momenta 3.0 - 4.2 GeV/c by detecting one charged ...particle in forward direction. The polarized neutron measurements are the first of their kind. The experiment was performed using the Nuclotron accelerator in JINR Dubna, where polarized neutrons and protons were obtained from breakup of a polarized deuteron beam which has a maximum momentum of 13 GeV/c. The polarimeter ALPOM2 was used to obtain the analyzing power dependence on the transverse momentum of the final-state nucleon. These data have been used to estimate the figure of merit of a proposed experiment at Jefferson Laboratory to measure the recoiling neutron polarization in the quasi-elastic
2
H
(
e
,
e
′
n
) reaction, which yields information on the charge and magnetic elastic form factors of the neutron.
The analyzing powers for proton elastic scattering (
p
A
→
p
X
) and neutron charge exchange (
n
A
→
p
X
) reactions on nuclei have been measured on
C
,
CH
,
C
H
2
and
Cu
targets at incident neutron ...momenta 3.0–4.2 GeV/c by detecting one charged particle in forward direction. The polarized neutron measurements are the first of their kind. The experiment was performed using the Nuclotron accelerator in JINR Dubna, where polarized neutrons and protons were obtained from break-up of a polarized deuteron beam which has a maximum momentum of 13 GeV/c. The polarimeter ALPOM2 was used to obtain the analyzing power dependence on the transverse momentum of the final-state nucleon. These data have been used to estimate the figure of merit of a proposed experiment at Jefferson Laboratory to measure the recoiling neutron polarization in the quasi-elastic
2
H
(
e
,
e
′
n
)
reaction, which yields information on the charge and magnetic elastic form factors of the neutron.
The analyzing powers for neutron charge exchange nA → pX reactions on nuclei have been measured on C, CH2 and Cu targets at incident neutron momenta 3.0 - 4.2 GeV/c by detecting one charged particle ...in forward direction. The polarized neutron measurements are the first of their kind. The experiment was performed using the Nuclotron accelerator in JINR Dubna, where polarized neutrons and protons were obtained from breakup of a polarized deuteron beam which has a maximum momentum of 13 GeV/c. The polarimeter ALPOM2 was used to obtain the analyzing power dependence on the transverse momentum of the final-state nucleon. These data have been used to estimate the figure of merit of a proposed experiment at Jefferson Laboratory to measure the recoiling neutron polarization in the quasi-elastic 2H(e, e′n) reaction, which yields information on the charge and magnetic elastic form factors of the neutron.
The differential cross sections of the charge exchange reaction dp → (pp)n has been measured at 1.75 GeV c momentum per nucleon for small transferred momenta using the one arm magnetic spectrometer ...STRELA at the Nuclotron accelerator. The ratio of the differential cross section of the charge exchange reaction dp → (pp)n to that of the np → pn elementary process is discussed in order to estimate the spin-dependent part of the np → pn charge exchange amplitude on the basis of dp → (pp)n data. The np → pn amplitude turned out to be predominantly spin-dependent.
The reaction p + CH2→ forward charge particle + X is used for this aim traditionally. Analyzing power of this reaction falls off as 1 p, where p is the laboratory momentum. At the proton momenta of ...order 8 GeV c, which are expected at the JLab experiment, the low analyzing power creates problems for off-line analysis of data. On the other hand, it is well known that the reaction p+p → p+p has the much more analyzing power. So, the calorimeter is predestinated for suppression of inelastic events in this reaction. In the report it is shown that the problem is solved quite well.
An accurate data base for the analyzing power of thick CH{sub 2} analyzers for high energy protons has been at the basis of several research efforts in a number of laboratories. Starting in the late ...eighties such data were collected at SATURNE in Saclay, and with the Synchrophasotron in Dubna, and led to an extensive program of study of polarization phenomena in pd interaction, either backward elastic scattering or breakup 1–6. At about the same time it became evident that measuring polarization observables in elastic ep was going to be the best approach to determine the form factors of the proton, G {sub Ep }and G {sub Mp }, as had been predicted by Akhiezer and Rekalo 7.
Two modular Cherenkov detectors FFD and T0 are developed for MPD and BM@N projects at LHEP/JINR for study of Au + Au collisions. The aim of the detectors is production of a start signal for a TOF ...detector and an effective L0 trigger for the collisions. The detector module design, characteristics, and results of tests with a deuteron beam are discussed. The time resolution of the modules for a single high energy photon or charged hadron is σ
t
≈ 21–31 ps and it depends on method and electronics used.
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