Thu·Apr 18, 2019Thursday·April 18, 2019

1. 01*

   NA61/SHINE results on Bose-Einstein correlations

   Barnabas Porfy (for the NA61/SHINE collaboration)🇭🇺

   One of the main goals of NA61/SHINE is the investigation of the phase diagram of strongly interacting matter. NA61/SHINE observes collisions of various nuclei at different energies, allowing to study the same phenomena and observables in vastly different conditions. One of the observables related to the quark-hadron transition is the Bose-Einstein momentum correlation function of identical pions, related to the space-time structure of pion emission. In this paper we report on such measurements in Be+Be collisions at an SPS beam momentum of 150A GeV/c. Our correlation functions can be statistically well described with Levy-distributed sources, hence we also study the mT dependence of the Levy source parameters, and discuss their possible interpretations.

   nucl-exhep-ex1 citation
2. 02*

   Electro-weak production of pseudovector C-even heavy quarkonia in electron-positron collisions on Belle II and BES III

   Nikolay Achasov🇷🇺

   It is shown that the molecular model for the X{3872) state contradicts the new experimental data as well as the old ones. It is suggested to study the \chi_{c1} and \chi_{b1} states in the e+e-\to\chi_{c1}/\chi_{b1} reactions.

   ↳ hep-phhep-exnucl-exEPJ Web Conf.(2019)·10 citations
3. 03*

   Systematic study of proton radioactivity based on Gamow--like model with a screened electrostatic barrier

   Jiu-Long Chen🇨🇳 · Xiao-Hua Li🇨🇳 · Jun-Hao Cheng🇨🇳 · Jun-Gang Deng · Xi-Jun Wu

   In the present work we systematically study the half--lives of proton radioactivity for $51\le Z\le 83$ nuclei based on the Gamow--like model with a screened electrostatic barrier. In this model there are two parameters while considering the screened electrostatic effect of Coulomb potential with the Hulthen potential i.e. the effective nuclear radius parameter r_0 and the screening parameter a. The calculated results can well reproduce the experimental data. In addition, we extend this model to predict the proton radioactivity half--lives of 16 nuclei in the same region within a factor of 2.94, whose proton radioactivity are energetically allowed or observed but not yet quantified. Meanwhile, studying on the proton radioactivity half-life by a type of universal decay law has been done. The results indicate that the calculated half--lives are linearly dependent on Coulomb parameter with the same orbital angular momentum.

   ↳ nucl-thnucl-exJ.Phys.G(2019)·24 citations
4. 04*

   Initial conditions of bulk matter in ultrarelativistic nuclear collisions

   J. Scott Moreland🇺🇸

   Dynamical models based on relativistic fluid dynamics provide a powerful tool to extract the properties of the strongly-coupled quark-gluon plasma (QGP) produced by ultrarelativistic nuclear collisions. The largest source of uncertainty in these model-to-data extractions is the choice of theoretical initial conditions (ICs) used to model the distribution of energy or entropy at the hydrodynamic starting time. Descriptions of the ICs are generally improved through iterative cycles of testing and refinement. Individual models are compared to experimental data; the worst models are discarded and best models retained. Consequently, successful traits (assumptions) are passed on to subsequent generations of the theoretical landscape. This bottom-up approach correspondingly describes a form of theoretical trial and error, where each trial proposes an ab initio solution to the problem at hand. A natural complement to this strategy, is to employ a top-down or data-driven approach which is able to reverse engineer properties of the ICs from the constraints imposed by the experimental data. In this dissertation, I motivate and develop a parametric IC model based on a family of functions known as the generalized means. The ansatz closely mimics the variability of ab initio calculations and serves as a reasonable parametric form for exploring QGP energy and entropy deposition assuming imperfect knowledge of the complex physical processes which lead to its creation. With the parametric model in hand, I explore broad implications of the proposed ansatz using recently adapted Bayesian methods to simultaneously constrain properties of the ICs and QGP medium using experimental data from the Large Hadron Collider. These analyses show that the ICs are highly constrained by available measurements and provide evidence of a unified hydrodynamic description of small and large nuclear collision systems.

   ↳ nucl-thnucl-ex9 citations
5. 05*

   Hadron-Deuteron Correlations and Production of Light Nuclei in Relativistic Heavy-Ion Collisions

   Stanislaw Mrowczynski🇵🇱 · Patrycja Slon🇵🇱

   The production of light nuclei in relativistic heavy-ion collisions is well described by both the thermal model, where light nuclei are in equilibrium with all other hadron species present in a fireball, and by the coalescence model, where light nuclei are formed due to final state interactions after the fireball decays. A method is proposed to falsify one of the models. We suggest to measure a hadron-deuteron correlation function which carries information about the source of the deuterons and allows one to determine whether a deuteron is directly emitted from the fireball or if it is formed afterwards. The $K^{-}-D$ and $p-D$ correlation functions are computed to illustrate the statement.

   ↳ nucl-thhep-phnucl-exActa Phys.Polon.B(2020)·52 citations
6. 06*

   Interface effects of strange quark matter

   Cheng-Jun Xia🇨🇳

   The interface effects play important roles for the properties of strange quark matter (SQM) and the related physical processes. We show several examples on the implications of interface effects for both stable and unstable SQM. Based on an equivparticle model and adopting mean-field approximation (MFA), the surface tension and curvature term of SQM can be obtained, which are increasing monotonically with the density of SQM at zero external pressure. For a parameter set constrained according to the 2$M_{\odot }$ strange star, we find the surface tension is $\sim$2.4 MeV/fm${}^2$, while it is larger for other cases.

   ↳ nucl-thastro-ph.HEnucl-exAIP Conf.Proc.(2019)·6 citations
7. 07*

   Initial operation of the recoil mass spectrometer EMMA at the ISAC-II facility of TRIUMF

   B. Davids🇨🇦 · M. Williams🇺🇸 · N.E. Esker · M. Alcorta🇪🇸 · D. Connolly · B.R. Fulton · K. Hudson · N. Khan · O.S. Kirsebom · J. Lighthall🇨🇦 · P. Machule🇨🇦

   The Electromagnetic Mass Analyser (EMMA) is a new vacuum-mode recoil mass spectrometer currently undergoing the final stages of commissioning at the ISAC-II facility of TRIUMF. EMMA employs a symmetric configuration of electrostatic and magnetic deflectors to separate the products of nuclear reactions from the beam, focus them in both energy and angle, and disperse them in a focal plane according to their mass/charge (m/q) ratios. The spectrometer was designed to accommodate the gamma-ray detector array TIGRESS around the target position in order to provide spectroscopic information from electromagnetic transitions. EMMA is intended to be used in the measurement of fusion evaporation, radiative capture, and transfer reactions for the study of nuclear structure and astrophysics. Its complement of focal plane detectors facilitates the identification of recoiling nuclei and subsequent recoil decay spectroscopy. Here we describe the facility and report on commissioning efforts.

   ↳ physics.ins-detnucl-exNucl.Instrum.Meth.A(2019)·9 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.