Wed·May 30, 2018Wednesday·May 30, 2018

1. 01*

   Statistical analysis of experimental multifragmentation events in ${}^{64}$Zn + ${}^{112}$Sn at 40 MeV/nucleon

   W. Lin🇨🇳 · H. Zheng🇨🇳 · P. Ren · X. Liu🇨🇳 · M. Huang🇺🇸 · R. Wada🇺🇸 · Z. Chen · J. Wang🇨🇳 · G. Q. Xiao🇨🇳 · G. Qu

   A statistical multifragmentation model (SMM) is applied to the experimentally observed multifragmentation events in an intermediate heavy ion reaction.Using the temperature and symmetry energy extracted from the isobaric yield ratio (IYR) method based on the Modified Fisher Model (MFM), SMM is applied to the reaction ${}^{64}$Zn + ${}^{112}$Sn at 40 MeV/nucleon. The experimental isotope distribution and mass distribution of the primary reconstructed fragments are compared without afterburner and they are well reproduced. The extracted temperature $T$ and symmetry energy coefficient $a_{sym}$ from SMM simulated events, using the IYR method, are also consistent with those from the experiment. These results strongly suggest that in the multifragmentation process there is a freezeout volume, in which the thermal and chemical equilibrium is established before or at the time of the intermediate-mass fragments emission.

   nucl-exPRC(2018)·6 citations
2. 02*

   Coupling between two extreme excitation mode in weakly deformed ${}^{142}$Eu nucleus

   Sajad Ali (1)🇮🇳 · S. Rajbanshi (1,2) · Prithwijita Ray (1)🇺🇸 · Somnath Nag (3) · Abhijit Bisoi (4) · S. Saha (5) · J. Sethi (6) · T. Trivedi (7) · T. Bhattacharjee (8)🇮🇳 · S. Bhattacharyya (8)🇮🇳 · S. Chattopadhyay (1)🇮🇳 · G. Gangopadhyay (9)🇮🇳 and 6 other authors

   Two opposite parity dipole bandlike structures DB I and DB II of ${}^{142}$Eu are investigated by the Indian National Gamma Array (INGA), using the fusion evaporation reaction ${}^{31}$P + ${}^{116}$Cd @ 148 MeV. The decreasing trend as well as magnitude of the measured $B(M1)$ and $B(E2)$ transition rates of the band DB II has been reproduced well within the shears mechanism with the principal axis cranking model calculations. This calculation reflects the fact that the maximum contribution of the angular momentum of the states in DB II has been generated from the magnetic rotation (MR) phenomenon. The enhanced $B(E1)$ rates of the connecting $E1$ transitions from the states of DB II to DB I are demanding the octupole correlation due to the involvement of the octupole driving pair of orbitals $\pi h_{11/2}$ and $\pi d_{5/2}$ as evident from the quasiparticle alignment ($i_x$), the experimental routhians (e${}^{{}^{\prime }}$) and the calculated neutron and proton quasiparticle energies against the rotational frequency ($\omega$).

   nucl-ex1 citation
3. 03*

   nEXO Pre-Conceptual Design Report

   nEXO Collaboration: S. Al Kharusi · A. Alamre · J.B. Albert · M. Alfaris · G. Anton · I.J. Arnquist · I. Badhrees · P.S. Barbeau · D. Beck · V. Belov · T. Bhatta · F. Bourque and 161 other authors

   The projected performance and detector configuration of nEXO are described in this pre-Conceptual Design Report (pCDR). nEXO is a tonne-scale neutrinoless double beta ($0\nu \beta \beta$) decay search in ${}^{136}$Xe, based on the ultra-low background liquid xenon technology validated by EXO-200. With $\simeq$ 5000 kg of xenon enriched to 90% in the isotope 136, nEXO has a projected half-life sensitivity of approximately $10^{28}$ years. This represents an improvement in sensitivity of about two orders of magnitude with respect to current results. Based on the experience gained from EXO-200 and the effectiveness of xenon purification techniques, we expect the background to be dominated by external sources of radiation. The sensitivity increase is, therefore, entirely derived from the increase of active mass in a monolithic and homogeneous detector, along with some technical advances perfected in the course of a dedicated R&D program. Hence the risk which is inherent to the construction of a large, ultra-low background detector is reduced, as the intrinsic radioactive contamination requirements are generally not beyond those demonstrated with the present generation $0\nu \beta \beta$ decay experiments. Indeed, most of the required materials have been already assayed or reasonable estimates of their properties are at hand. The details described herein represent the base design of the detector configuration as of early 2018. Where potential design improvements are possible, alternatives are discussed. This design for nEXO presents a compelling path towards a next generation search for $0\nu \beta \beta$, with a substantial possibility to discover physics beyond the Standard Model.

   ↳ physics.ins-detnucl-ex154 citations
4. 04*

   Bulk viscosity coefficient of hadronic matter

   Sabyasachi Ghosh🇮🇳 · Sandeep Chatterjee🇮🇳 · Bedangadas Mohanty🇮🇳

   The bulk viscosity coefficient of hadronic matter has been estimated in this present work, where the thermodynamical equilibrium quantity like speed of sound in the medium has been obtained by using standard hadron resonance gas model. Whereas, the non-equilibrium quantity like thermal widths of medium constituents have been calculated in the framework field theory at finite temperature. Our values of bulk viscosity coefficient are in agreement with some earlier estimations.

   ↳ nucl-thhep-phnucl-exSpringer Proc.Phys.(2018)·0 citations
5. 05*

   ${\Lambda }^{\ast }(1405)$-matter: stable or unstable?

   Jaroslava Hrtánková🇨🇿 · Nir Barnea🇮🇱 · Eliahu Friedman🇮🇱 · Avraham Gal🇮🇱 · Jiří Mareš🇨🇿 · Martin Schäfer🇨🇿

   A recent suggestion [PLB 774 (2017) 522] that purely-${\Lambda }^{\ast }(1405)$ nuclei provide the absolute minimum energy in charge-neutral baryon matter for baryon-number $A\gtrsim 8$, is tested within RMF calculations. A broad range of ${\Lambda }^{\ast }$ interaction strengths, commensurate with $(\bar{K}\bar{K}NN{)}_{I=0}$ binding energy assumed to be of order 100 MeV, is scanned. It is found that the binding energy per ${\Lambda }^{\ast }$, $B/A$, saturates for $A\gtrsim 120$ with values of $B/A$ considerably below 100 MeV, implying that ${\Lambda }^{\ast }(1405)$ matter is highly unstable against strong decay to $\Lambda$ and $\Sigma$ hyperon aggregates. The central density of ${\Lambda }^{\ast }$ matter is found to saturate as well, at roughly twice nuclear matter density. Moreover, it is shown that the underlying very strong $\bar{K}N$ potentials, fitted for isospin $I=0$ to the mass and width values of ${\Lambda }^{\ast }(1405)$, fail to reproduce values of single-nucleon absorption fractions deduced across the periodic table from $K^{-}$ capture-at-rest bubble chamber experiments.

   ↳ nucl-thhep-phnucl-exPLB(2018)·15 citations
6. 06*

   Deuteron production from phase-space coalescence in the UrQMD approach

   Sukanya Sombun🇹🇭 · Kristiya Tomuang🇹🇭 · Ayut Limphirat🇹🇭 · Paula Hillmann🇩🇪 · Christoph Herold🇹🇭 · Jan Steinheimer🇩🇪 · Yupeng Yan🇹🇭 · Marcus Bleicher🇩🇪

   UrQMD phase-space coalescence calculations for the production of deuterons are compared with available data for various reactions from the GSI/FAIR energy regime up to LHC. It is found that the production process of deuterons, as reflected in their rapidity and transverse momentum distributions in p+p, p+A and A+A collisions at a beam energies starting from the GSI energy regime around 1 AGeV and up to the LHC, are in good agreement with experimental data. We further explore the energy and centrality dependence of the d/p ratios. Finally, we discuss anti-deuteron production for selected systems. Overall, a good description of the experimental data is observed. The results are also compatible with thermal model estimates. Most importantly this good description is based only on a single set of coalescence parameters that is independent of energy system size and can also be applied for anti-deuterons.

   ↳ nucl-thhep-phnucl-exPRC(2019)·120 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.