Nuclear Theory·nucl-th

Friday·September 18, 2015

13 papers—7 primary·6 cross-listed

01
Direct Urca processes involving singlet proton superfluidity in neutron star cooling
Yan Xu · Xiu Lin Huang · Xiao Jun Zhang · Tmurbagan Bao · Lin Xiao · Cun Bo Fan · Cheng Zhi Liu
A detailed description of the baryon direct Urca processes A: $n \to p + e + ν ˉ_{e}$ , B: $Λ \to p + e + ν ˉ_{e}$ , C: $Ξ^{-} \to Λ + e + ν ˉ_{e}$ related to the neutron star cooling is given in the relativistic mean field approximation.The contributions of the reactions B and C on the neutrino luminosity are calculated by means of the relativistic expressions of the neutrino energy losses.Our results show that the total neutrino luminosities of the reactions A, B, C within the mass range 1.603-2.067 $M_{⊙}$ (1.515-1.840 $M_{⊙}$ for TM1 model) for GM1 model are larger than the corresponding values for neutron stars in npe $μ$ matter. Although the hyperon direct Urca processes B and C reduce the neutrino emissivity of the reaction A, it illustrates the reactions B and C still make the total neutrino luminosity enhancement in the above mentioned areas.Furthermore, when we only consider the $^{1} S_{0}$ proton superfluidity in neutron star cooling, we find that although the neutrino emissivity of the reactions A and B is suppressed with the appearance of $^{1} S_{0}$ proton superfluidity, the total contribution of the reactions A, B, C can still quicken a massive neutron star cooling.These results could be used to help prove appearing hyperons in PSR J1614-2230 and J0348+0432 from neutron star cooling perspective.
nucl-thCommun.Theor.Phys.(2018)·5 citations
02
Deconfinement Phase Transition with External Magnetic Field in Friedberg-Lee Model
Shijun Mao🇨🇳
The deconfinement phase transition with external magnetic field is investigated in the Friedberg-Lee model. In the frame of functional renormalization group, we extend the often used potential expansion method for continuous phase transitions to the first-order phase transition in the model. By solving the flow equations we find that, the magnetic field displays a catalysis effect and it becomes more difficult to break through the confinement in hot and dense medium.
nucl-thChin.Phys.Lett.(2016)·2 citations
03
Phase space factors and half-life predictions for Majoron emitting $β^{-} β^{-}$ decay
J. Kotila🇫🇮 · J. Barea🇨🇱 · F. Iachello🇺🇸
A complete calculation of phase space factors (PSF) for Majoron emitting $0 ν β^{-} β^{-}$ decay modes is presented. The calculation makes use of exact Dirac wave functions with finite nuclear size and electron screening and includes life-times, single electron spectra, summed electron spectra, and angular electron correlations. Combining these results with recent interacting boson nuclear matrix elements (NME) we make half-life predictions for the the ordinary Majoron decay (spectral index $n$ =1). Furthermore, comparing theoretical predictions with the obtained experimental lower bounds for this decay mode we are able to set limits on the effective Majoron-neutrino coupling constant $⟨ g_{ee}^{M} ⟩$ .
nucl-thPRC(2015)·51 citations
04
Neutrinoless double positron decay and positron emitting electron capture in the interacting boson model
J. Barea🇨🇱 · J. Kotila🇺🇸 · F. Iachello🇺🇸
Neutrinoless double- $β$ decay is of fundamental importance for determining the neutrino mass. Although double electron ( $β^{-} β^{-}$ ) decay is the most promising mode, in very recent years interest in double positron ( $β^{+} β^{+}$ ) decay, positron emitting electron capture ( $E C β^{+}$ ), and double electron capture ( $E C E C$ ) has been renewed. We present here results of a calculation of nuclear matrix elements for neutrinoless double- $β^{+}$ decay and positron emitting electron capture within the framework of the microscopic interacting boson model (IBM-2) for $^{58}$ Ni, $^{64}$ Zn, $^{78}$ Kr, $^{96}$ Ru, $^{106}$ Cd, $^{124}$ Xe, $^{130}$ Ba, and $^{136}$ Ce decay. By combining these with a calculation of phase space factors we calculate expected half-lives.
nucl-thPRC(2013)·35 citations
05
Production of antimatter $^{5, 6}$ Li nuclei in central Au+Au collisions at $s_{N N} = 200$ GeV
Kai-Jia Sun🇨🇳 · Lie-Wen Chen🇨🇳
Combining the covariant coalescence model and a blast-wave-like analytical parametrization for (anti-)nucleon phase-space freezeout configuration, we explore light (anti-)nucleus production in central Au+Au collisions at $s_{N N} = 200$ GeV. Using the nucleon freezeout configuration (denoted by FO1) determined from the measured spectra of protons (p), deutrons (d) and $^{3}$ He, we find the predicted yield of $^{4}$ He is significantly smaller than the experimental data. We show this disagreement can be removed by using a nucleon freezeout configuration (denoted by FO2) in which the nucleons are assumed to freeze out earlier than those in FO1 to effectively consider the effect of large binding energy value of $^{4}$ He. Assuming the binding energy effect also exists for the production of $^{5} Li$ , $^{5} Li$ , $^{6} Li$ and $^{6} Li$ due to their similar binding energy values as $^{4}$ He, we find the yields of these heavier (anti-)nuclei can be enhanced by a factor of about one order, implying that although the stable (anti-) $^{6}$ Li nucleus is unlikely to be observed, the unstable (anti-) $^{5}$ Li nucleus could be produced in observable abundance in Au+Au collisions at $s_{N N} = 200$ GeV where it may be identified through the p- $^{4} He$ ( $p$ - $^{4} He$ ) invariant mass spectrum. The future experimental measurement on (anti-) $^{5} Li$ would be very useful to understand the production mechanism of heavier antimatter.
nucl-thastro-ph.COhep-phnucl-exPLB(2015)·40 citations
06
Reference calculations for subthreshold $Ξ$ production
Boris Tomasik🇨🇿 · Evgeni E Kolomeitsev🇸🇰
We present a minimal statistical model designed for the description of rare-hadron multiplicities in nucleus-nucleus collisions at energies below the threshold of the particle production in binary elementary collisions. Differences to more conventional canonical statistical model are explained. The minimal statistical model is applied to the description of multiplicity ratios involving $Ξ$ hyperons, which are measured by the HADES collaboration at GSI-SIS. It is argued that the HADES data cannot be reproduced by the model based on the statistical equilibrium and the strangeness conservation. The data remain underpredicted even when in-medium potentials acting on hadrons are taken into account. This hints to non-equilibrium production of the $Ξ$ hyperons and their continuous freeze-out.
nucl-thhep-phJ.Phys.Conf.Ser.(2016)·0 citations
07
Blast wave fits with resonances to $p_{t}$ spectra from nuclear collisions at the LHC
Ivan Melo🇸🇰 · Boris Tomasik🇸🇰
We report our results for the freeze-out temperature and transverse flow profile obtained from fits to hadronic spectra measured by the ALICE collaboration. The influence of resonance decays is important and cannot be simply accounted for without the inclusion of their decays into the fits.
nucl-thnucl-exJ.Phys.Conf.Ser.(2016)·5 citations

Affiliations

first authorsco-authorsvia INSPIRE

Direct Urca processes involving singlet proton superfluidity in neutron star cooling

Deconfinement Phase Transition with External Magnetic Field in Friedberg-Lee Model

Phase space factors and half-life predictions for Majoron emitting β−β− decay

Neutrinoless double positron decay and positron emitting electron capture in the interacting boson model

Production of antimatter 5,6Li nuclei in central Au+Au collisions at sNN​​=200 GeV

Reference calculations for subthreshold Ξ production

Blast wave fits with resonances to pt​ spectra from nuclear collisions at the LHC

Affiliations

Phase space factors and half-life predictions for Majoron emitting $β^{-} β^{-}$ decay

Production of antimatter $^{5, 6}$ Li nuclei in central Au+Au collisions at $s_{N N} = 200$ GeV

Reference calculations for subthreshold $Ξ$ production

Blast wave fits with resonances to $p_{t}$ spectra from nuclear collisions at the LHC