The dissociation of relativistic
12
N nuclei having a momentum of 2 GeV/
c
per nucleon and undergoing the most peripheral interactions in a track emulsion is studied. The picture of charged topology ...of product ensembles of relativistic fragments and special features of their angular distributions are presented.
The charge topology in the fragmentation of
10
C nuclei in a track nuclear emulsion at an energy of 1.2 GeV per nucleon is studied. In the coherent dissociation of
10
C nuclei, about 82% of events ...are associated with the channel
10
C → 2
α
+ 2
p
. The angular distributions and correlations of product fragments are presented for this channel. It is found that among
10
C → 2
α
+ 2
p
events, about 30% are associated with the process in which dissociation through the ground state of the unstable
9
Be
g.s.
nucleus is followed by
8
Be
g.s.
+
p
decays.
Experimental results on the vector (
A
y
) and tensor (
A
yy
) analyzing powers in the fragmentation of 5- and 9-GeV/
c
polarized deuterons to high-momentum pions in the kinematical region ...corresponding to pion production on a strongly correlated nucleon pair (cumulative meson production) are presented. The angular and momentum dependences of
A
yy
are not described by calculations performed in the impulse approximation by using standard deuteron wave functions. An explanation for our data should be sought on the basis of models that treat the deuteron at short distances (deuteron-core region) as a multiquark state—for example, a 6
q
cluster, whose high orbital angular momentum (
D
wave) leads to the observed strong dependence of the reaction tensor analyzing power
A
(
, π)
X
on the pion transverse momentum.
The dissociation of relativistic \(^{12}\)N nuclei having a momentum of 2 GeV/c per nucleon and undergoing the most peripheral interactions in a track emulsion is studied. The picture of charged ...topology of product ensembles of relativistic fragments and special features of their angular distributions are presented.
A nuclear track emulsion was exposed to a mixed beam of relativistic sup.12N, sup.10C, and sup.7Be nuclei having a momentum of 2 GeV/c per nucleon. The beam was formed upon charge exchange processes ...involving sup.12C primary nuclei and their fragmentation. An analysis indicates that sup.10C nuclei are dominant in the beam and that sup.12N nuclei are present in it. The charge topology of relativistic fragments in the coherent dissociation of these nuclei is presented.
The momentum distribution of electrons from semileptonic decays of charm and bottom quarks for midrapidity |y|<0.35 in p+p collisions at sq root(s)=200 GeV is measured by the PHENIX experiment at the ...Relativistic Heavy Ion Collider over the transverse momentum range 2<p{sub T}<7 GeV/c. The ratio of the yield of electrons from bottom to that from charm is presented. The ratio is determined using partial D/D->e{sup +}-K{sup +}-X (K unidentified) reconstruction. It is found that the yield of electrons from bottom becomes significant above 4 GeV/c in p{sub T}. A fixed-order-plus-next-to-leading-log perturbative quantum chromodynamics calculation agrees with the data within the theoretical and experimental uncertainties. The extracted total bottom production cross section at this energy is sigma{sub bb}=3.2{sub -1.1}{sup +1.2}(stat){sub -1.3}{sup +1.4}(syst)mub.
Bose-Einstein correlations of charged kaons are used to probe Au+Au collisions at sq root(s{sub NN})=200 GeV and are compared to charged pion probes, which have a larger hadronic scattering cross ...section. Three-dimensional Gaussian source radii are extracted, along with a one-dimensional kaon emission source function. The centrality dependences of the three Gaussian radii are well described by a single linear function of N{sub part}{sup 1/3} with a zero intercept. Imaging analysis shows a deviation from a Gaussian tail at r > or approx. 10 fm, although the bulk emission at lower radius is well described by a Gaussian. The presence of a non-Gaussian tail in the kaon source reaffirms that the particle emission region in a heavy-ion collision is extended, and that similar measurements with pions are not solely due to the decay of long-lived resonances.
The double helicity asymmetry in neutral pion production for p{sub T}=1 to 12 GeV/c was measured with the PHENIX experiment to access the gluon-spin contribution, DELTAG, to the proton spin. Measured ...asymmetries are consistent with zero, and at a theory scale of mu{sup 2}=4 GeV{sup 2} a next to leading order QCD analysis gives DELTAG{sup 0.02,0.3}=0.2, with a constraint of -0.7<DELTAG{sup 0.02,0.3}<0.5 at DELTAchi{sup 2}=9 (approx3sigma) for the sampled gluon momentum fraction (x) range, 0.02 to 0.3. The results are obtained using predictions for the measured asymmetries generated from four representative fits to polarized deep inelastic scattering data. We also consider the dependence of the DELTAG constraint on the choice of the theoretical scale, a dominant uncertainty in these predictions.
Slowly extracted relativistic beams of light nuclei and a beam transportation line net system constitute a good base for secondary nuclear beams forming at the LHE accelerator facility. A recent ...years activity in the field at the Laboratory is connected with a project on study light nuclei structure by means the emulsion technique 1,2. The paper shortly summarizes results of the work.
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