Nuclear Experiment·nucl-ex
5 papers—0 primary·5 cross-listed·reconstructed*
R. Bijker🇲🇽 · O.A. Díaz-Caballero
We study electromagnetic transition rates in the framework of the algebraic cluster model. The concept of shape-phase transitions is used to propose a mechanism that allows to have interband and intraband quadrupole transitions of comparable strength, as observed in 12C.
Shaowei Lan🇨🇳 · Zi-Wei Lin🇺🇸 · Shusu Shi🇨🇳 · Xu Sun🇨🇳
In non-central relativistic heavy ion collisions, the created matter possesses a large initial orbital angular momentum. Particles produced in the collisions could be polarized globally in the direction of the orbital angular momentum due to spin-orbit coupling. Recently, the STAR experiment has presented polarization signals for hyperons and possible spin alignment signals for mesons. Here we discuss the effects of finite coverage on these observables. The results from a multi-phase transport and a toy model both indicate that a pseudorapidity coverage narrower than will generate a larger value for the extracted -meson parameter; thus a finite coverage can lead to an artificial deviation of from 1/3. We also show that a finite and coverage affect the extracted parameter for hyperons when the real value is non-zero. Therefore proper corrections are necessary to reliably quantify the global polarization with experimental observables.
K. Nomura🇫🇷 · R Rodríguez-Guzmán🇰🇼 · L. M. Robledo🇪🇸
The interacting boson-fermion model (IBFM), with parameters determined from the microscopic Hartree-Fock-Bogoliubov (HFB) approximation, based on the parametrization D1M of the Gogny energy density functional (EDF), is employed to study the structural evolution in odd-mass -soft nuclei. The deformation energy surfaces of even-even nuclei, single-particle energies and occupation probabilities of the corresponding odd-mass systems have been obtained within the constrained HFB approach. Those building blocks are then used as a microscopic input to build the IBFM Hamiltonian. The coupling constants of the boson-fermion interaction terms are taken as free parameters, fitted to reproduce experimental low-lying spectra. The diagonalization of the IBFM Hamiltonian provides the spectroscopic properties for the studied odd-mass nuclei. The procedure has been applied to compute low-energy excitation spectra and electromagnetic transition rates, in the case of the -soft odd-mass systems Ba, Xe, La and Cs. The calculations provide a reasonable agreement with the available experimental data and agree well with previous results based on the relativistic mean-field approximation.
Eugenio Berti (for the LHCf collaboration)🇮🇹
The main aim of the LHCf experiment is to provide precise measurements of the production spectra relative to neutral particle produced by high energy proton-ion collisions in the very forward region. This information is necessary in order to test and tune hadronic interaction models used by ground-based cosmic rays experiments. In order to reach this goal, LHCf makes use of two small sampling calorimeters installed in the LHC tunnel at m from IP1, able to detect neutral particles having pseudo-rapidity . In this paper we will present the current status of the LHCf experiment, regarding in particular the first analysis results from data taking relative to p-p collisions at 13 TeV.
Ferenc Siklér (for the CMS Collaboration)🇭🇺
Short range correlations of identified charged hadrons in pp ( 0.9, 2.76, and 7 TeV), pPb ( 5.02 TeV), and peripheral PbPb collisions ( 2.76 TeV) are studied with the CMS detector at the LHC. Charged pions, kaons, and protons at low momentum and in laboratory pseudorapidity are identified via their energy loss in the silicon tracker. The two-particle correlation functions show effects of quantum statistics, Coulomb interaction, and also indicate the role of multi-body resonance decays and mini-jets. The characteristics of the one-, two-, and three-dimensional correlation functions are studied as a function of transverse pair momentum, , and the charged-particle multiplicity of the event. The extracted radii are in the range 1-5 fm, reaching highest values for very high multiplicity pPb, also for similar multiplicity PbPb collisions, and decrease with increasing . The dependence of radii on multiplicity and largely factorizes and appears to be insensitive to the type of the colliding system and center-of-mass energy.
* 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.