Wed·Sep 2, 2020Wednesday·September 2, 2020

1. 01*

   First Observation of Multiple Transverse Wobbling Bands of Different Kinds in ${}^{183}$Au

   S. Nandi · G. Mukherjee🇮🇳 · Q. B. Chen🇩🇪 · S. Frauendorf🇺🇸 · R. Banik🇮🇳 · Soumik Bhattacharya🇮🇳 · Shabir Dar · S. Bhattacharyya🇮🇳 · C. Bhattacharya🇮🇳 · S. Chatterjee🇮🇳 · S. Das🇮🇳 · S. Samanta and 9 other authors

   We report the first observation of two wobbling bands in ${}^{183}$Au, both of which were interpreted as the transverse wobbling (TW) band but with different behavior of their wobbling energies as a function of spin. It increases (decreases) with spin for the positive (negative) parity configuration. The crucial evidence for the wobbling nature of the bands, dominance of the $E2$ component in the $\Delta I=1$ transitions between the partner bands, is provided by the simultaneous measurements of directional correlation from the oriented states (DCO) ratio and the linear polarization of the $\gamma$ rays. Particle rotor model calculations with triaxial deformation reproduce the experimental data well. A value of spin, $I_m$, has been determined for the observed TW bands below which the wobbling energy increases and above which it decreases with spin. The nucleus ${}^{183}$Au is, so far, the only nucleus in which both the increasing and the decreasing parts are observed and thus gives the experimental evidence of the complete transverse wobbling phenomenon.

   nucl-exPRL(2020)·57 citations
2. 02*

   Statistical and Dynamical Model Studies of Nuclear Multifragmentation Reactions at Intermediate Energies

   S. Mallik🇮🇳

   Nuclear multifragmentation is an important phenomenon, the study of which can throw light on reaction mechanism in heavy ion collisions at intermediate and high energies. Based on statistical and dynamical model studies, this thesis is concentrated mainly on, the following three aspects of nuclear multifragmentation reactions namely (i) production of exotic nuclei which are normally not available in the laboratory (ii) nuclear symmetry energy from heavy ion collisions at intermediate energies and (iii) Nuclear liquid-gas phase transition. In addition to these equivalence of statistical ensembles under different conditions is also studied in the framework of multifragmentation.

   ↳ nucl-thnucl-ex1 citation
3. 03*

   Effect of liquid drop model parameters on nuclear liquid gas phase transition

   G. Chaudhuri🇮🇳 · S. Mallik🇮🇳

   The phenomenon of liquid-gas phase transition occurring in heavy ion collisions at intermediate energies is a subject of contemporary interest. In statistical models of fragmentation, the liquid drop model is generally used to calculate the ground state binding energies of the fragments. It is well known that the surface and symmetry energy of the hot fragments at the low density freeze out can be considerably modified. In addition to this, the level density parameter also has a wide variation. The effect of variation of these parameters is studied on fragmentation observables which are related to the nuclear liquid gas phase transition. The canonical thermodynamical model which has been very successful in describing the phenomenon of fragmentation is used for the study. The shift in transition temperature owing to the variation in liquid drop model parameters has been examined.

   ↳ nucl-thnucl-exPRC(2019)·5 citations
4. 04*

   New method for calculating electromagnetic effects in semileptonic beta-decays of mesons

   Chien-Yeah Seng🇩🇪 · Xu Feng🇨🇳 · Mikhail Gorchtein🇩🇪 · Lu-Chang Jin🇺🇸 · Ulf-G. Meißner🇩🇪

   We construct several classes of hadronic matrix elements and relate them to the low-energy constants in Chiral Perturbation Theory that describe the electromagnetic effects in the semileptonic beta decay of the pion and the kaon. We propose to calculate them using lattice QCD, and argue that such a calculation will make an immediate impact to a number of interesting topics at the precision frontier, including the outstanding anomalies in $|V_{us}|$ and the top-row Cabibbo-Kobayashi-Maskawa matrix unitarity.

   ↳ hep-lathep-exhep-phnucl-ex+1JHEP(2020)·38 citations
5. 05*

   Development of an array of HPGe detectors with 980% relative efficiency

   D. S. Leonard🇰🇷 · I. S. Hahn🇰🇷 · W. G. Kang🇰🇷 · V. Kazalov🇷🇺 · G. W. Kim🇰🇷 · Y. D. Kim🇰🇷 · E. K. Lee🇰🇷 · M. H. Lee🇰🇷 · S. Y. Park🇰🇷 · E. Sala🇰🇷

   Searches for new physics push experiments to look for increasingly rare interactions. As a result, detectors require increasing sensitivity and specificity, and materials must be screened for naturally occurring, background-producing radioactivity. Furthermore the detectors used for screening must approach the sensitivities of the physics-search detectors themselves, thus motivating iterative development of detectors capable of both physics searches and background screening. We report on the design, installation, and performance of a novel, low-background, fourteen-element high-purity germanium detector named the CAGe (CUP Array of Germanium), installed at the Yangyang underground laboratory in Korea.

   ↳ physics.ins-dethep-exnucl-exNucl.Instrum.Meth.A(2021)·7 citations
6. 06*

   Isospin dependent hybrid model for studying isoscaling in heavy ion collisions around the Fermi energy domain

   S. Mallik🇮🇳 · G. Chaudhuri🇮🇳

   Investigation of observables from nuclear multifragmentation reactions depending on isospin led to the development of a hybrid model. The mass and charge distribution as well as isotopic distribution was studied using this model for ${}^{112}$Sn+${}^{112}$Sn reaction as well as ${}^{124}$Sn+${}^{124}$Sn reactions at different energies. The agreement of the results obtained from the model with those from experimental data confirms the accuracy of the model. Isoscaling coefficients were extracted from these observables which can throw light on the symmetry energy coefficient. Another important facet of this model is that temperature of the studied reaction can be directly extracted using this model.

   ↳ nucl-thnucl-exNPA(2020)·13 citations
7. 07*

   Conception and software implementation of a nuclear data evaluation pipeline

   Georg Schnabel🇸🇪 · Henrik Sjöstrand🇸🇪 · Joachim Hansson · Dimitri Rochman🇨🇭 · Arjan Koning🇦🇹 · Roberto Capote🇦🇹

   We discuss the design and software implementation of a nuclear data evaluation pipeline applied for a fully reproducible evaluation of neutron-induced cross sections of ${}^{56}$Fe above the resolved resonance region using the nuclear model code TALYS combined with relevant experimental data. The emphasis is on the mathematical and technical aspects of the pipeline and not on the evaluation of ${}^{56}$Fe, which is tentative. The mathematical building blocks combined and employed in the pipeline are discussed in detail. A unified representation of experimental data, systematic and statistical errors, model parameters and defects enables the application of the Generalized Least Squares (GLS) and its natural extension, the Levenberg-Marquardt (LM) algorithm, on a large collection of experimental data. The LM algorithm tailored to nuclear data evaluation accounts for the exact non-linear physics model to determine best estimates of nuclear quantities. Associated uncertainty information is derived from a Taylor expansion at the maximum of the posterior distribution. We also discuss the pipeline in terms of its IT (=information technology) building blocks, such as those to efficiently manage and retrieve experimental data of the EXFOR library and to distribute computations on a scientific cluster. Relying on the mathematical and IT building blocks, we elaborate on the sequence of steps in the pipeline to perform the evaluation, such as the retrieval of experimental data, the correction of experimental uncertainties using marginal likelihood optimization (MLO) and after a screening of thousand TALYS parameters -- including Gaussian process priors on energy dependent parameters -- the fitting of about 150 parameters using the LM algorithm. The code of the pipeline including a manual and a Dockerfile for a simplified installation is available at www.nucleardata.com.

   ↳ physics.data-annucl-exnucl-thphysics.comp-phNucl.Data Sheets(2021)·11 citations
8. 08*

   Nuclear Multifragmentation: Basic Concepts

   G. Chaudhuri🇮🇳 · S. Mallik🇮🇳 · S. Das Gupta

   We present a brief overview of nuclear multifragmentation reaction. Basic formalism of canonical thermodynamical model based on equilibrium statistical mechanics is described. This model is used to calculate basic observables of nuclear multifragmentation like mass distribution, fragment multiplicity, isotopic distribution and isoscaling. Extension of canonical thermodynamical model to a projectile fragmentation model is outlined. Application of the projectile fragmentation model for calculating average number of intermediate mass fragments and the average size of largest cluster at different $Z_{bound}$, differential charge distribution and cross-section of neutron rich nuclei of different projectile fragmentation reactions at different energies are described. Application of nuclear multifragmentation reaction in basic research as well as in other domains is outlined.

   ↳ nucl-thnucl-exPramana(2014)·0 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.