Tue·Mar 8, 2016Tuesday·March 8, 2016

1. 01*

   Nuclear fusion induced by X-rays in a crystal

   V. B. Belyaev🇷🇺 · M. B. Miller🇺🇸 · J. Otto · S. A. Rakityansky🇿🇦

   The nuclei that constitute a crystalline lattice, oscillate relative to each other with a very low energy that is not sufficient to penetrate through the Coulomb barriers separating them. An additional energy, which is needed to tunnel through the barrier and fuse, can be supplied by external electromagnetic waves (X-rays or the synchrotron radiation). Exposing to the X-rays the solid compound LiD (lithium-deuteride) for the duration of 111 hours, we have detected 88 events of the nuclear fusion d+Li6 ---> Be8*. Our theoretical estimate agrees with what we observed. One of possible applications of the phenomenon we found, could be the measurements of the rates of various nuclear reactions (not necessarily fusion) at extremely low energies inaccessible in accelerator experiments.

   nucl-exnucl-thPRC(2016)·2 citations
2. 02*

   Fluctuations in Charged Particle Multiplicities in Relativistic Heavy-Ion Collisions

   Maitreyee Mukherjee🇮🇳 · Sumit Basu🇮🇳 · Subikash Choudhury🇮🇳 · Tapan K. Nayak🇮🇳

   Multiplicity distributions of charged particles and their event-by-event fluctuations have been compiled for relativistic heavy-ion collisions from the available experimental data at Brookhaven National Laboratory and CERN and also by the use of an event generator. Multiplicity fluctuations are sensitive to QCD phase transition and to the presence of critical point in the QCD phase diagram. In addition, multiplicity fluctuations provide baselines for other event-by-event measurements. Multiplicity fluctuation expressed in terms of the scaled variance of the multiplicity distribution is an intensive quantity, but is sensitive to the volume fluctuation of the system. The importance of the choice of narrow centrality bins and the corrections of centrality bin width effect for controlling volume fluctuations have been discussed. It is observed that the mean and width of the multiplicity distributions monotonically increase as a function of increasing centrality at all collision energies, whereas the multiplicity fluctuations show minimal variations with centrality. The beam energy dependence shows that the multiplicity fluctuations have a slow rise at lower collision energies and remain constant at higher energies.

   nucl-exhep-exhep-phnucl-thJ.Phys.G(2016)·17 citations
3. 03*

   Extracting the resonance parameters from experimental data on scattering of charged particles

   P. Vaandrager · S. A. Rakityansky🇿🇦

   A new parametrization of the multi-channel S-matrix is used to fit scattering data and then to locate the resonances as its poles. The S-matrix is written in terms of the corresponding "in" and "out" Jost matrices which are expanded in the Taylor series of the collision energy E around an appropriately chosen energy E0. In order to do this, the Jost matrices are written in a semi-analytic form where all the factors (involving the channel momenta and Sommerfeld parameters) responsible for their "bad behaviour" (i.e. responsible for the multi-valuedness of the Jost matrices and for branching of the Riemann surface of the energy) are given explicitly. The remaining unknown factors in the Jost matrices are analytic and single-valued functions of the variable E and are defined on a simple energy plane. The expansion is done for these analytic functions and the expansion coefficients are used as the fitting parameters. The method is tested on a two-channel model, using a set of artificially generated data points with typical error bars and a typical random noise in the positions of the points.

   ↳ nucl-thnucl-exIJMPE(2016)·6 citations
4. 04*

   Full jet evolution in quark-gluon plasma and nuclear modification of jet production and jet shape in Pb+Pb collisions at 2.76 ATeV at the LHC

   Ning-Bo Chang🇨🇳 · Guang-You Qin🇨🇳

   We study the evolution of full jet shower in quark-gluon plasma via solving a set of coupled differential transport equations for the three-dimensional momentum distributions of quarks and gluons contained in the full jets. In our jet evolution equations, we include all partonic splitting processes as well as the collisional energy loss and transverse momentum broadening for both the leading and radiated partons of the full jets. Combining with a realistic (2+1)-dimensional viscous hydrodynamic simulation for the space-time profiles of the hot and dense nuclear medium produced in heavy-ion collisions, we apply our formalism to calculate the nuclear modification of single inclusive full jet spectra, the momentum imbalance of photon-jet and dijet pairs, and jet shape function (at partonic level) in Pb+Pb collisions at 2.76 ATeV. The roles of various jet-medium interaction mechanisms on the full jet modification are studied. We find that the nuclear modification of jet shape is sensitive to the interplay of different interaction mechanisms as well as the energies of the full jets.

   ↳ hep-phnucl-exnucl-thPRC(2016)·77 citations
5. 05*

   Study of compound nucleus formation via bremsstrahlung emission in proton $\alpha$-particle scattering

   Sergei P. Maydanyuk (1 and 2)🇺🇦 · Peng-Ming Zhang (1 and 3) ((1) Institute of Modern Physics, Chinese Academy of Sciences, (2) Institute for Nuclear Research, National Academy of Sciences of Ukraine, (3) State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences)🇨🇳

   In this paper a role of many-nucleon dynamics in formation of the compound ${}^5\mathrm{Li}$ nucleus in the scattering of protons off $\alpha$-particles at the proton incident energies up to 20 MeV is investigated. We propose a bremsstrahlung model allowing to extract information about probabilities of formation of such nucleus on the basis of analysis of experimental cross-sections of the bremsstrahlung photons. In order to realize this approach, the model includes elements of microscopic theory and also probabilities of formation of the short-lived compound nucleus. Results of calculations of the bremsstrahlung spectra are in good agreement with the experimental cross-sections.

   ↳ nucl-thhep-phnucl-ex0 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.