arXiv subjects
Publications and source records attributed to D. A. Artemenkov.
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 $\rightarrow$ 2$α+$ 2\emph{p}. The angular distributions and correlations of product fragments are presented for this channel. It is found that among $^{10}$C $\rightarrow$ 2$α+$ 2\emph{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$_{g.s.} +$ \emph{p} decays.
Nuclear track emulsion is exposed to a beam of radioactive $^8$He nuclei with an energy of 60 MeV and enrichment of about 80% at the ACCULINNA separator. Measurements of 278 decays of the $^8$He nuclei stopped in the emulsion allow the potential of the $α$ spectrometry to be estimated and the thermal drift of $^8$He atoms in matter to be observed for the first time.
We analyze the self-similarity approach applied to study the hadron production in p-p and A-A collisions. This approach allows us to describe rather well the ratio of the proton to anti-proton yields in A-A collisions as a function of the energy at a wide range from a few GeV to a few TeV. We suggest a modification of this approach to describe rather well the inclusive spectra of hadrons produced in $pp$ collisions at different initial energies from the AGS to LHC.
Charge topology of fragmentation of 1.2 A GeV $^7$Be nuclei in nuclear track emulsion is presented.The dissociation channels $^4$He + $^3$He, 2$^3$He+ n, $^4$He + 2$^1$H are considered in detail. It is established that the events $^6$Be + n amount about to 27 % in the channel $^4$He + 2$^1$H.
The fragment separator ACCULINNA in the G. N. Flerov Laboratory of Nuclear Reactions of JINR was used to expose a nuclear track emulsion to a beam of radioactive $^{8}$He nuclei of energy of 60 MeV and enrichment of about 80%. Measurements of decays of $^{8}$He nuclei stopped in the emulsion allow one to evaluate possibilities of $α$-spectrometry and to observe a thermal drift of $^{8}$He atoms in matter. Knowledge of the energy and emission angles of $α$-particles allows one to derive the energy distribution of $α$-decays Q$_{2α}$. The presence of a "tail" of large values Q$_{2α}$ is established. The physical reason for the appearance of this "tail" in the distribution Q$_{2α}$ is not clear. Its shape could allow one to verify calculations of spatial structure of nucleon ensembles emerging as $α$-pairs of decays via the state $^8$Be$_{2+}$.
The dissociation features in nuclear track emulsion of $^9$Be, $^{9,10}$C, and $^{12}$N nuclei of 1.2 A GeV energy are presented. The data presented for the nucleus $^9$Be can be considered as evidence that there is a core in its structure in the form of 0$^+$ and 2$^+$ states of the $^8$Be nucleus having roughly equal weights. Events of coherent dissociation $^9$C$\rightarrow 3^3$He associated with the rearrangement of the nucleons outside the $α$-clustering are identified. A pattern of the charge fragment topology in the dissociation of $^{10}$C and $^{12}$N nuclei is obtained for the first time. Contribution of the unbound nucleus decays to the cascade process $^{10}$C$\rightarrow ^9$B$\rightarrow ^8$Be is identified.
Nuclear track emulsion is exposed to 1.2 A $^9$C GeV nuclei. Pairs of 2$^3$He nuclei having unusually narrow opening angles are observed in channel $^9$C $\rightarrow$ 3$^3$He pointing to the possible 2$^3$He resonance near the production threshold.
Dissociation of 1.2 A GeV $^{10}$C nuclei in nuclear track emulsionis is studied. It is shown that most precise angular measurements provided by this technique play a crucial role in the restoration of the excitation spectrum of the 2$α$+2p system. Strong contribution of the cascade process $^{10}$C$\rightarrow ^9$B$\rightarrow ^8$Be identified.
A nuclear track emulsion was exposed to a mixed beam of relativistic $^{12}$N, $^{10}$C, and $^7$Be nuclei having a momentum of 2 GeV/$c$ per nucleon. The beam was formed upon charge exchange processes involving $^{12}$C primary nuclei and their fragmentation. An analysis indicates that $^{10}$C nuclei are dominant in the beam and that $^{12}$N nuclei are present in it. The charge topology of relativistic fragments in the coherent dissociation of these nuclei is presented.
Results on the coherent dissociation of relativistic $^9$C nuclei in a nuclear track emulsion are described. These results include the charge topology and kinematical features of final states. Events of C-9 to 3He-3 coherent dissociation are identified.
We present the theoretical results on the forward Lambda_b production in pp collisions obtained within the soft QCD, namely the quark gluon string model, at LHC energies. It can give us useful information on the Regge trajectories of the (b{\bar b}) mesons. An opportunity to find the information on the intrinsic charm and bottom in the proton by analyzing the forward heavy flavour hadron production in pp collisions is discussed.
We present the theoretical results on the forward Lambda_b production in pp collisions obtained within the soft QCD, namely the quark gluon string model, at LHC energies. It can give us useful information on the Regge trajectories of the bottom mesons.
The technique of nuclear track emulsions is used to explore the fragmentation of light relativistic nuclei down to the most peripheral interactions - nuclear "white" stars. A complete pattern of therelativistic dissociation of a $^8$B nucleus with target fragment accompaniment is presented. Relativistic dissociation $^{9}$Be$\to2α$ is explored using significant statistics and a relative contribution of $^{8}$Be decays from 0$^+$ and 2$^+$ states is established. Target fragment accompaniments are shown for relativistic fragmentation $^{14}$N$\to$3He+H and $^{22}$Ne$\to$5He. The leading role of the electromagnetic dissociation on heavy nuclei with respect to break-ups on target protons is demonstrated in all these cases. It is possible to conclude that the peripheral dissociation of relativistic nuclei in nuclear track emulsion is a unique tool to study many-body systems composed of lightest nuclei and nucleons in the energy scale relevant for nuclear astrophysics.
Experimental data on fragmentation channels in peripheral interactions of $^8$B nuclei in nuclear track emulsions are presented. A detailed analysis made it possible to justify selections of events of the electromagnetic-dissociation process $^8$B $\to^7$Be + \emph{p} and to estimate its cross section. Events of $^{10}$C peripheral dissociation that were observed in the same exposure are described.
\indent First results of the exposure of nuclear track emulsions in a secondary beam enriched by $^9$C nuclei at energy of 1.2 A GeV are described. The presented statistics corresponds to the most peripheral $^9$C interactions. For the first time a dissociation $^9$C $\to3^3$He not accompanied by target fragments and mesons is identified.\par
Recent studies of clustering in light nuclei with an initial energy above 1 A GeV in nuclear treack emulsion are overviewed. The results of investigations of the relativistic $^9$Be nuclei fragmentation in emulsion, which entails the production of He fragments, are presented. It is shown that most precise angular measurements provided by this technique play a crucial role in the restoration of the excitation spectrum of the $α$ particle sysytem. In peripheral interactions $^9$Be nuclei are dissociated practically totally through the 0$^+$ and 2$^+$ states of the $^8$Be nucleus. The results of investigations of the dissociation of a $^{14}$N nucleus of momentum 2.86 A GeV/c in emulsion are presented as example of more complicated system. The momentum and correlation characteristics of $α$ particles for the $^{14}$N$\to3α+X$ channel in the laboratory system and the rest systems of 3$α$ particles were considered in detail. Topology of charged fragments produced in peripheral relativistic dissociation of radioactive $^8$B, $^7$Be nuclei in emulsion is studied.
Experimental results on peripheral fragmentation of relativistic $^{11}$B nuclei are presented. In the experiment the emulsions exposured to $^{11}$B beam with momentum 2.75 A GeV/c at the JINR Nuclotron are used. The relative probability of various fragmentation channels for nucleus breakups (class A) and more violent peripheral interactions (class B) have been determined. For classes under investigations the sum of the fragment charges in narrow forward cone is equal to the projectile charge, but in the events of class A there are no secondary particles and in the events of class B there are. In both classes the main channels is $^{11}$B$\to$2He+X: 62% and 50%, corresponding. The main channel $^{11}$B$\to$2(Z$_{fr}$=2)+(Z$_{fr}$=1) was investigated in details. Momentum measurements of single-charged fragments have been done to determine number of p, d and t in the channel. This way it was found that the ratio N$_{p}$ : N$_{d}$ : N$_{t}$ is about 1:1:1 for $^{11}$B nuclei dissociation and about 15:5:1 for peripheral interactions of $^{11}$B nuclei.