Tue·Jul 17, 2018Tuesday·July 17, 2018

1. 01*

   Neutron inelastic scattering measurements on ${}^{136}$Xe at $E_n$ = 0.7 to 100 MeV

   S. J. Daugherty🇺🇸 · J. B. Albert🇺🇸 · L. J. Kaufman🇺🇸 · M. Devlin🇺🇸 · N. Fotiades🇺🇸 · R. O. Nelson🇺🇸 · M. Krtička🇨🇿

   Experiments searching for neutrinoless double beta decay ($0\nu \beta \beta$) require precise energy calibration and extremely low backgrounds. One of the most popular isotopes for $0\nu \beta \beta$ experiments is ${}^{136}$Xe. In support of these experiments, the neutron inelastic scattering properties of this isotope have been measured at the GErmanium Array for Neutron Induced Excitations (GEANIE) at the Los Alamos Neutron Science Center. Time-of-flight techniques are utilized with high-purity germanium detectors to search for inelastic scattering $\gamma$ rays for neutron energies between 0.7 and 100 MeV. Limits are set on production of yet-unobserved $\gamma$ rays in the energy range critical for $0\nu \beta \beta$ studies, and measurements are made of multiple $\gamma$-ray production cross sections. In particular, we have measured the production of the 1313 keV $\gamma$ ray which comes from the transition of the first-excited to ground state of ${}^{136}$Xe. This neutron-induced $\gamma$ line may be useful for a novel energy calibration technique, described in this paper.

   nucl-exphysics.ins-detPRC(2018)·1 citation
2. 02*

   Directed flow of quarks from the RHIC Beam Energy Scan measured by STAR

   Gang Wang (for the STAR Collaboration)🇺🇸

   Directed flow ($v_1$) is a good probe of the early-stage dynamics of collision systems, and the $v_1$ slope at midrapidity ($d{v}_1/dy{|}_{y=0}$) is sensitive to the system's equation of state. STAR has published $v_1(y)$ measurements for ten particle species (${\pi }^{\pm }$, $p$, $\bar{p}$, $\Lambda$, $\bar{\Lambda }$, $\varphi$, $K^{\pm }$ and $K_S^0$) in Au+Au collisions at eight beam energies from $\sqrt{s_{NN}}=7.7$ GeV to 200 GeV. In this study, we employ a simple coalescence idea to decompose $v_1$ of hadrons into $v_1$ of constituent quarks. The $d{v}_1/dy$ values of $\bar{p}$, $K^{-}$ and $\bar{\Lambda }$ are used to test the coalescence sum rule for produced quarks. Data involving produced quarks support the coalescence picture at $\sqrt{s_{NN}}=11.5$ GeV to 200 GeV, and a sharp deviation from this picture is observed at 7.7 GeV. The $d{v}_1/dy$ of transported quarks is studied via net particles (net $p$ and net $\Lambda$). In these proceedings, we further extract the $v_1$ slopes of produced and transported quarks, assuming that the coalescence sum rule is valid.

   nucl-exNPA(2019)·3 citations
3. 03*

   Drifting Photons on Optical Paths: Mirrors, Sub-mm Resolution in 4 Dimensions, and Transverse/Longitudinal Phase Space: Exploiting Time Resolution

   Henry J. Frisch🇺🇸

   I discuss the status of MCP-based photo-detector amplification sections and Cherenkov light sources for precise timing measurements of charged particles and gamma rays. Sub-psec resolution is predicted for the large pulses such as those produced by a charged particle or electromagnetic shower traversing a photo-detector entrance window. Measuring events with sub-mm resolution in each of the 4 dimensions expands the optical phase space from 4 dimensions, allowing emittance transformations that can minimize expensive instrumented photo-sensitive area.

   ↳ physics.ins-detastro-ph.IMhep-exhep-ph+1PoS(2019)·3 citations
4. 04*

   New measures of longitudinal decorrelation of harmonic flow

   Piotr Bozek🇵🇱 · Wojciech Broniowski🇵🇱

   Harmonic flow in relativistic heavy-ion collisions is observed in a broad range of rapidities, and the flow at different rapidities is correlated. However, fluctuations lead to a small decorrelation of the harmonic flow magnitudes and flow angles at different rapidities. Using a hydrodynamic model with Glauber Monte Carlo initial conditions we show that the flow angle decorrelation strongly depends on the flow magnitude in the event. We propose observables to measure this effect in experiment.

   ↳ nucl-thhep-phnucl-exNPA(2019)·1 citation
5. 05*

   IP-Glasma Phenomenology Beyond 2D

   Scott McDonald🇨🇦 · Sangyong Jeon🇨🇦 · Charles Gale🇨🇦

   We present a novel formulation of the IP-Glasma initial state model in 3+1D in which the 2+1D boost invariant IP-Glasma is generalized through JIMWLK rapidity evolution of the pre-collision Wilson lines \cite{Schenke:2016ksl}. In order to consistently accommodate a non-boost-invariant system, the initial conditions are generalized to 3+1D. By breaking boost invariance, the 3+1D model no longer trivially satisfies Gauss' law at the initial time, and we now enforce it locally. We compare the time evolution of the chromo-electric and chromo-magnetic fields as well as the transverse and longitudinal pressures in the 3+1D case with the boost invariant result.

   ↳ nucl-thhep-phnucl-exNPA(2019)·16 citations
6. 06*

   Hydrodynamic Fluctuations in Relativistic Heavy-Ion Collisions

   Mayank Singh🇨🇦 · Chun Shen🇺🇸 · Scott McDonald🇨🇦 · Sangyong Jeon🇨🇦 · Charles Gale🇨🇦

   We present a novel approach to the treatment of thermal fluctuations in the (3+1)-D viscous hydrodynamic simulation MUSIC. The phenomenological impact of thermal fluctuations on hadronic observables is investigated using the IP-Glasma + hydrodynamics + hadronic cascade hybrid approach. The anisotropic flow observed in heavy-ion collision experiments is mostly attributed to the hydrodynamic response to the event-by-event collision geometry and to the sub-nucleon quantum fluctuations. However, hydrodynamic fluctuations are present during the dynamical evolution of the Quark Gluon Plasma (QGP) and are quantified by the fluctuation-dissipation theorem. They can leave their imprint on final-state observables. By analyzing the thermal noise mode-by-mode, we provide a consistent scheme of treating these fluctuations as the source terms for hydrodynamic fields. These source terms are then evolved together with hydrodynamic equations of motion. Such a treatment captures the non-perturbative nature of the evolution for these thermal fluctuations.

   ↳ nucl-thhep-phnucl-exNPA(2019)·59 citations
7. 07*

   Energy response of X-rays under high flux conditions using a thin APD for the energy range of 6-33 keV

   T. Masuda🇯🇵 · T. Hiraki · H. Kaino · S. Kishimoto · Y. Miyamoto · K. Okai · S. Okubo · R. Ozaki · N. Sasao🇯🇵 · K. Suzuki🇦🇹 · S. Uetake · A. Yoshimi🇯🇵 · K. Yoshimura🇯🇵

   This paper reports on the demonstration of a high-rate energy measurement technique using a thin depletion layer silicon avalanche photodiode (Si-APD). A dedicated amplitude-to-time converter is developed to realize simultaneous energy and timing measurement in a high rate condition. The energy response of the system is systematically studied by using monochromatic X-ray beam with an incident energy ranging from 6 to 33 keV. The obtained energy spectra contain clear peaks and tail distributions. The peak fraction monotonously decreases as the incident photon energy increases. This phenomenon can be explained by considering the distribution of the energy deposit in silicon, which is investigated by using a Monte Carlo simulation.

   ↳ physics.ins-detnucl-exNucl.Instrum.Meth.A(2019)·2 citations
8. 08*

   High precision nuclear mass predictions towards a hundred kilo-electron-volt accuracy

   Zhongming Niu🇨🇳 · Haozhao Liang🇯🇵 · Baohua Sun🇨🇳 · Yifei Niu🇷🇴 · Jianyou Guo🇨🇳 · Jie Meng🇨🇳

   Mass is a fundamental property and an important fingerprint of atomic nucleus. It provides an extremely useful test ground for nuclear models and is crucial to understand energy generation in stars as well as the heavy elements synthesized in stellar explosions. Nuclear physicists have been attempting at developing a precise, reliable, and predictive nuclear model that is suitable for the whole nuclear chart, while this still remains a great challenge even in recent days. Here we employ the Fourier spectral analysis to examine the deviations of nuclear mass predictions to the experimental data and to present a novel way for accurate nuclear mass predictions. In this analysis, we map the mass deviations from the space of nucleon number to its conjugate space of frequency, and are able to pin down the main contributions to the model deficiencies. By using the radial basis function approach we can further isolate and quantify the sources. Taking a pedagogical mass model as an example, we examine explicitly the correlation between nuclear effective interactions and the distributions of mass deviations in the frequency domain. The method presented in this work, therefore, opens up a new way for improving the nuclear mass predictions towards a hundred kilo-electron-volt accuracy, which is argued to be the chaos-related limit for the nuclear mass predictions.

   ↳ nucl-thnucl-exSci.Bull.(2018)·45 citations
9. 09*

   Chiral Magnetic Effect in Isobaric Collisions from Anomalous-Viscous Fluid Dynamics (AVFD)

   Shuzhe Shi🇺🇸 · Hui Zhang🇨🇳 · Defu Hou🇨🇳 · Jinfeng Liao🇺🇸

   The isobaric collision experiment at RHIC provides the unique opportunity to detect the possible signal of Chiral Magnetic Effect (CME) in heavy ion collisions. The idea is to contrast the correlation observables of the two colliding systems that supposedly have identical flow-driven background contributions while quite different CME signal contributions due to the 10% variation in their nuclear charge and thus magnetic field strength. With the recently developed quantitative simulation tool for computing CME signal, the Anomalous-Viscous Fluid Dynamics (AVFD), we demonstrate that a joint (multiplicity + elliptic-flow) event selection is crucial for this purpose. We further propose to use the absolute difference between RuRu and ZrZr events (after using identical event selection) for detecting CME signal and make predictions for the correlation observables.

   ↳ hep-phnucl-exnucl-thNPA(2019)·11 citations
10. 10*

    Hadronic observables in p+p and d+Au collisions at RHIC using CGC+PYTHIA

    Björn Schenke🇺🇸 · Sören Schlichting🇺🇸 · Prithwish Tribedy🇺🇸 · Raju Venugopalan🇺🇸

    The IP-Glasma model of CGC combined with the Lund model of PYTHIA provides a very successful description of hadron production from gluon dominated non-equilibrium matter in various small collision systems. This new CGC+PYTHIA framework, naturally reproduces several characteristic features of the hadronic observables such as the mass ordering of $v_2(p_T)$ and $⟨p_T⟩$, often ascribed to collectivity driven by hydrodynamics at the LHC. In this contribution we extend our work to provide a systematic comparison of particle spectra and multiplicity distributions in p+p and d+Au collisions at the RHIC.

    ↳ nucl-thhep-phnucl-exNPA(2019)·3 citations
11. 11*

    Nucleus-nucleus potential from identical-particle interference

    Ning Wang🇨🇳 · Yongxu Yang🇨🇳 · Min Liu🇨🇳 · Chengjian Lin🇨🇳

    Based on the quantum interference between two-identical-nucleus scattering at energies around the Coulomb barrier, the barrier positions for ${}^{58}$Ni+${}^{58}$Ni and ${}^{16}$O+${}^{16}$O are extracted from Mott oscillations in the angular distributions around 90${}^{\circ }$ for the first time. The angle separation of pairs of Mott scattering valleys around 90${}^{\circ }$ has a direct relationship with the closest distance between two nuclei in elastic scattering. Together with the barrier height from fusion excitation function, the extracted barrier position provides a sensitive probe to constrain the model predictions for the nucleus-nucleus potential barrier.

    ↳ nucl-thnucl-exquant-phPLB(2018)·1 citation
12. 12*

    Unified framework for heavy flavor and quarkonium production in high multiplicity p+p and p+A collisions at RHIC and LHC

    Yan-Qing Ma🇨🇳 · Prithwish Tribedy🇺🇸 · Raju Venugopalan🇺🇸 · Kazuhiro Watanabe🇺🇸

    We discuss the production of $D$-mesons and $J/\psi$ in high multiplicity proton-proton and proton-nucleus collisions within the Color-Glass-Condensate (CGC) framework. We demonstrate that the modification of the LHC data on $D$ and $J/\psi$ yields in high multiplicity events relative to minimum bias events arise from a significant enhancement of the gluon saturation scales of the corresponding rare parton configurations in the colliding protons and nuclei. For a given event multiplicity, we predict these relative yields to be energy independent from $\sqrt{s}=200$ GeV at RHIC to the highest LHC energies.

    ↳ hep-phhep-exnucl-exnucl-thNPA(2019)·3 citations
13. 13*

    Applications of deep learning to relativistic hydrodynamics

    Hengfeng Huang🇨🇳 · Bowen Xiao🇨🇳 · Huixin Xiong🇨🇳 · Zeming Wu🇨🇳 · Yadong Mu🇨🇳 · Huichao Song (Peking U)🇨🇳

    In this proceeding, we will briefly review our recent progress on implementing deep learning to relativistic hydrodynamics. We will demonstrate that a successfully designed and trained deep neural network, called {\tt stacked U-net}, can capture the main features of the non-linear evolution of hydrodynamics, which could also rapidly predict the final profiles for various testing initial conditions.

    ↳ nucl-thcond-mat.dis-nnhep-exhep-ph+1NPA(2019)·5 citations
14. 14*

    Testing coalescence and statistical-thermal production scenarios for (anti-)(hyper-)nuclei and exotic QCD objects at energies available at the CERN Large Hadron Collider

    Francesca Bellini🇨🇭 · Alexander Philipp Kalweit🇨🇭

    We present a detailed comparison of coalescence and thermal-statistical models for the production of (anti-)(hyper-)nuclei in high-energy collisions. For the first time, such a study is carried out as a function of the size of the object relative to the size of the particle emitting source. Our study reveals large differences between the two scenarios for the production of objects with extended wave-functions. While both models give similar predictions and show similar agreement with experimental data for (anti-)deuterons and (anti-)3He nuclei, they largely differ in their description of (anti-)hyper-triton production. We propose to address experimentally the comparison of the production models by measuring the coalescence parameter systematically for different (anti-)(hyper-)nuclei in different collision systems and differentially in multiplicity. Such measurements are feasible with the current and upgraded Large Hadron Collider experiments. Our findings highlight the unique potential of ultra-relativistic heavy-ion collisions as a laboratory to clarify the internal structure of exotic QCD objects and can serve as a basis for more refined calculations in the future.

    ↳ hep-phnucl-exnucl-thPRC(2019)·114 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.