122532580
Incomplete fusion dynamics by spin distribution measurements
Spin distributions for various evaporation residues populated via complete and incomplete fusion of $^{16}\mathrm{O}$ with $^{124}\mathrm{Sn}$ at $6.3$ MeV/nucleon have been measured, using charged particles ($Z=1,2$)-$\ensuremath{\gamma}$ coincidence technique. Experimentally measured spin distributions of the residues produced as incomplete fusion products associated with ``fast'' $\ensuremath{\alpha}$- and $2\ensuremath{\alpha}$-emission channels observed in the ``forward cone'' are found to be distinctly different from those of the residues produced as complete fusion products. Moreover, ``fast'' $\ensuremath{\alpha}$-particles that arise from larger angular momentum in the entrance channel are populated at relatively higher driving input angular momentum than those produced through complete fusion. The incomplete fusion residues are populated in a limited, higher-angular-momentum range, in contrast to the complete fusion products, which are populated over a broad spin range.
120483275
Role of high ℓ values in the onset of incomplete fusion
A particle-$\ensuremath{\gamma}$-coincidence experiment is performed to investigate the role of high $\ensuremath{\ell}$ values in the production of direct-$\ensuremath{\alpha}$-emitting channels (associated with incomplete fusion) in $^{12}\mathrm{C}+^{169}\mathrm{Tm}$ system. Spin distributions of various $\mathit{xn}/\mathit{pxn}/\ensuremath{\alpha}\mathit{xn}/2\ensuremath{\alpha}\mathit{xn}$ channels are measured at ${E}_{\mathrm{lab}}=5.6A$ and $6.5A$ MeV. Entirely different de-excitation patterns are observed in direct-$\ensuremath{\alpha}$-emitting channels and fusion-evaporation channels. The fusion-evaporation channels are found to be strongly fed over a broad spin range. While narrow range feeding for only high-spin states was observed in the case of direct-$\ensuremath{\alpha}$-emitting channels, in the present work, incomplete fusion is shown to be a promising tool to populate high-spin states in final reaction products. To have better insight into the associated $\ensuremath{\ell}$ values in different reaction channels, the present data are compared with similar data obtained in $^{16}\mathrm{O}({E}_{\mathrm{lab}}\ensuremath{\approx}5.6A \mathrm{MeV}) + ^{169}\mathrm{Tm}$ system. The mean driving angular momenta involved in the production of direct-$\ensuremath{\alpha}$-emitting channels are found to be higher than those involved in the production of fusion-evaporation channels. Direct-$\ensuremath{\alpha}$ multiplicity in the forward cone increases with driving angular momenta, which indicates the origin of direct-$\ensuremath{\alpha}$-emitting channels at high $\ensuremath{\ell}$ values in noncentral interactions.
40508283
Equilibrium and preequilibrium emission in some alpha -induced reactions on enriched isotopes 128,130Te at moderate excitation energies.
Excitaion functions for the reactions [sup 128]Te([alpha],[ital np])[sup 130]I, [sup 130]Te([alpha],[ital np])[sup 132]I, and [sup 130]Te([alpha],[ital np])[sup 132[ital m]]I have been measured using the stacked foil technique and have also been calculated using a statistical model with and without the inclusion of preequilibrium emission. As expected, the inclusion of preequilibrium emission in compound nucleus calculations agrees well with the experimental excitation functions. The preequilibrum fraction has been found to be energy and target mass number dependent.
121591753
Reaction mechanism in the O 16 + Al 27 system: Measurements and analysis of excitation functions and angular distributions
To study the dynamics of heavy ion fusion reactions in the lower mass region, experiments were carried out to measure the cross sections of radioactive residues produced in the interaction of the {sup 16}O ion with {sup 27}Al target nucleus at 19 different energies in very close intervals covering the energy range from {approx_equal}58 to 94 MeV, using the well-known recoil catcher off-line {gamma}-ray spectroscopy technique. The simulation of experimental data was performed using statistical-model-based computer codes, viz., CASCADE, PACE2, and ALICE-91. The analysis of measured excitation functions indicates that these residues are likely to be produced by complete fusion, incomplete fusion, and direct reaction processes. Furthermore, to confirm the contribution of different reaction channels, a complementary experiment was performed that measured the angular distributions of the residues produced in the {sup 16}O+{sup 27}Al system at 85 MeV beam energy. The analysis of the results of both experiments indicates that at these energies, the direct reactions compete with complete fusion and incomplete fusion reaction processes.
122406045
Preequilibrium emission in α induced reactions on bromine and thallium
119401910
Complete and incomplete fusion of 12 C with 165 Ho below 7 MeV/nucleon: Measurements and analysis of excitation functions
This experiment has been done with a view to studying complete and incomplete fusion in heavy-ion-induced reactions. Excitation functions for several reactions induced by ${}^{12}{\mathrm{C}}^{5+}$ ions on ${}^{165}\mathrm{Ho}$ at incident energies from 55 to 80 MeV have been measured using the activation technique. The analysis of the data has been done using the codes ALICE-91 and CASCADE. The parameter ${F}_{\ensuremath{\theta}},$ the ratio of actual moment of inertia to the rigid-body value, has been found to play an important role in the calculations done by the code CASCADE. Significant contributions from both the complete and the incomplete fusion channels have been observed. Further, in the case of the reaction $(\mathrm{C},p3n)$ considerable contribution from the decay of higher charge isobar precursor has been observed.
60626146
ILC Reference Design Report: ILC Global Design Effort and World Wide Study
121070748
Integral frequency distribution of projectile alpha fragments in nuclear multifragmentations at intermediate and high energies
The integral frequency distributions of the numbers of projectile alpha fragments produced in nuclear multifragmentations at intermediate and high energies are studied by a simple two-source model. The calculated results are approximately in agreement with the experimental data of 16 O, 40 Ar, 56 Fe, 84 Kr, 139 La, and 197 Au multifragmentations in nuclear emulsions at 2.00 A , 1.80 A , 1.80 A , 0.08–1.70 A , 0.60–0.99 A , and 0.60–0.99 A GeV, respectively. The initial energy of nuclear limiting fragmentation is expected to be at or lower than 0.08 A GeV. Two correlations between the mean multiplicity of projectile alpha fragments ( 〈 n α 〉 ) and the projectile mass number, as well as 〈 n α 〉 and the maximum multiplicity of projectile alpha fragments are observed.
118402519
Cross sections and double-helicity asymmetries of midrapidity inclusive charged hadrons in p+ p collisions at sqrt (s)= 62.4 GeV
Unpolarized cross sections and double-helicity asymmetries of single-inclusive positive and negative charged hadrons at midrapidity from p + p collisions at root s = 62.4 GeV are presented. The PHENIX measurement of the cross sections for 1.0 < p(T) < 4.5 GeV/c are consistent with perturbative QCD calculations at next-to-leading order in the strong-coupling constant, alpha(s). Resummed pQCD calculations including terms with next-to-leading-log accuracy, yielding reduced theoretical uncertainties, also agree with the data. The double-helicity asymmetry, sensitive at leading order to the gluon polarization in a momentum-fraction range of 0.05 less than or similar to x(gluon) less than or similar to 0.2, is consistent with recent global parametrizations disfavoring large gluon polarization.
121361611
Some general properties of projectile fragments in 40Ar interactions in nuclear emulsions at 1.8 A GeV
An analysis of projectile fragments has been performed using 40Ar-emulsion interactions at 1.8 A GeV. The interaction mean free path of 40Ar nuclei was obtained on the basis of 4600 events which enabled one to calculate the total inelastic cross section. Correlations between the multiplicity of different charged particles were studied extensively to get an insight into the reaction mechanism. The average number of interacting nucleons of the projectile was calculated and compared with results from other experiments. Events with projectile fragments were divided into various reaction channels and several parameters like average emission angle and target particle multiplicities were studied as a function of target mass in different reaction channels. The projectile fragmentation properties were found to be independent of the target for peripheral collisions.
18129865
Transition in yield and azimuthal shape modification in dihadron correlations in relativistic heavy ion collisions.
Hard-scattered parton probes produced in collisions of large nuclei indicate large partonic energy loss, possibly with collective produced-medium response to the lost energy. We present measurements of π^{0} trigger particles at transverse momenta p{T}{t}=4-12  GeV/c and associated charged hadrons (p{T}{a}=0.5-7  GeV/c) vs relative azimuthal angle Δϕ in Au+Au and p+p collisions at sqrt[s{NN}]=200  GeV. The Au+Au distribution at low p{T}{a}, whose shape has been interpreted as a medium effect, is modified for p{T}{t}<7  GeV/c. At higher p{T}{t}, the data are consistent with unmodified or very weakly modified shapes, even for the lowest measured p{T}{a}, which quantitatively challenges some medium response models. The associated yield of hadrons opposing the trigger particle in Au+Au relative to p+p (I{AA}) is suppressed at high p{T} (I{AA}≈0.35-0.5), but less than for inclusive suppression (R{AA}≈0.2).