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Nuclear Theory·nucl-th

Wednesday·August 15, 2018

5 papers—2 primary·3 cross-listed

All5Primary2Cross-lists3
  1. 03

    Precision Mass Measurement of Cr: Nuclear Collectivity towards the \emph{N}=40 Island of Inversion

    Maxime Mougeot🇫🇷 · Dinko Atanasov🇩🇪 · Klaus Blaum🇩🇪 · Katherina Chrysalidis🇨🇭 · Tom Day Goodacre🇨🇭 · Dmitrii Fedorov🇷🇺 · Valentin Fedosseev🇨🇭 · Sebastian George🇩🇪 · Frank Herfurth🇩🇪 · Jason D. Holt🇨🇦 · David Lunney🇫🇷 · Vladimir Manea🇨🇭 and 13 other authors

    The neutron-rich isotopes Cr were produced for the first time at the ISOLDE facility and their masses were measured with the ISOLTRAP spectrometer. The new values are up to 300 times more precise than those in the literature and indicate significantly different nuclear structure from the new mass-surface trend. A gradual onset of deformation is found in this proton and neutron mid-shell region, which is a gateway to the second island of inversion around \emph{N}=40. In addition to comparisons with density-functional theory and large-scale shell-model calculations, we present predictions from the valence-space formulation of the \emph{ab initio} in-medium similarity renormalization group, the first such results for open-shell chromium isotopes.

    ↳ nucl-exnucl-thPRL(2018)·53 citations
  2. 04

    On the Rotational Invariance and Non-Invariance of Lepton Angular Distributions in Drell-Yan and Quarkonium Production

    Jen-Chieh Peng🇺🇸 · Daniel Boer🇳🇱 · Wen-Chen Chang🇹🇼 · Randall Evan McClellan🇺🇸 · Oleg Teryaev🇷🇺

    Several rotational invariant quantities for the lepton angular distributions in Drell-Yan and quarkonium production were derived several years ago, allowing the comparison between different experiments adopting different reference frames. Using an intuitive picture for describing the lepton angular distribution in these processes, we show how the rotational invariance of these quantities can be readily obtained. This approach can also be used to determine the rotational invariance or non-invariance of various quantities specifying the amount of violation for the Lam-Tung relation. While the violation of the Lam-Tung relation is often expressed by frame-dependent quantities, we note that alternative frame-independent quantities are preferred.

    ↳ hep-phnucl-thPLB(2019)·17 citations
  3. 05

    Probing heavy ion collisions using quark and gluon jet substructure with machine learning

    Yang-Ting Chien🇺🇸

    Understanding the inner working of the quark-gluon plasma requires complete and precise jet substructure studies in heavy ion collisions. In this proceeding we discuss the use of quark and gluon jets as independent probes, and how their classification allows us to uncover regions of QCD phase space sensitive to medium dynamics. We introduce the telescoping deconstruction (TD) framework to capture complete jet information and show that TD observables reveal fundamental properties of quark and gluon jets and their modifications in the medium. We draw connections to soft-drop subjet distributions and illuminate medium-induced jet modifications using Lund diagrams. The classification is also studied using a physics-motivated, multivariate analysis of jet substructure observables. Moreover, we apply image-recognition techniques by training a deep convolutional neural network on jet images to benchmark classification performances. We find that the quark gluon discrimination performance worsens in \textsc{Jewel}-simulated heavy ion collisions due to significant soft radiation affecting soft jet substructures. This work suggests a systematic framework for jet studies and facilitates direct comparisons between theoretical calculations and measurements in heavy ion collisions.

    ↳ hep-phnucl-exnucl-thNPA(2019)·8 citations

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first authorsco-authorsvia INSPIRE