Nuclear Theory·nucl-th

Tuesday·December 18, 2018

16 papers—7 primary·9 cross-listed

01
Towards an extraction of $q^$ with an uncertainty controlled energy loss Monte-Carlo
Weiyao Ke🇺🇸 · Yingru Xu🇺🇸 · Steffen A. Bass🇺🇸
Recent progress in open-heavy-flavor measurements and future experimental upgrades are bringing heavy-flavor physics into the precision era, allowing for strong quantitative constraints on the transport properties of heavy quarks in the quark-gluon plasma. Starting from the LIDO transport model, which combines a matrix-element based linearized-Boltzmann transport and diffusion-based Langevin equation, we have made two essential improvements to increase both the flexibility and physical accuracy of the model. First, we have absorbed the pQCD scatterings with small momentum transfers to the medium into the diffusion part of the LIDO model, and we have restricted the use of vacuum matrix elements to large momentum transfer processes. This study allows us to construct a model that smoothly interpolates between a pure pQCD based approach and a radiation-improved Langevin equation by tuning a single scale parameter. Second, the Monte-Carlo implementation of the Landau-Pomeranchuk-Migdal effect of the original model has been improved to account for multiple scatterings of gluons. The simulated radiative energy loss can be tuned to quantitatively agree with semi-analytic theory calculations both for a static (finite / infinite) medium and for a dynamic expanding medium. With such improvements, the LIDO model will greatly facilitate the extraction of heavy-quark transport coefficient from a systematic model-to-data comparison.
nucl-th1 citation
02
Resonance production in high energy collisions from small to big systems
K. Werner🇫🇷 · A. G. Knospe🇺🇸 · C. Markert🇺🇸 · B. Guiot🇫🇷 · Iu. Karpenko🇫🇷 · T. Pierog🇩🇪 · G. Sophys🇫🇷 · M. Stefaniak🇫🇷 · M. Bleicher🇩🇪 · J. Steinheimer🇩🇪
The aim of this paper is to understand resonance production (and more generally particle production) for different collision systems, namely proton-proton (pp), proton-nucleus (pA), and nucleus-nucleus (AA) scattering at the LHC. We will investigate in particular particle yields and ratios versus multiplicity, using the same multiplicity definition for the three different systems, in order to analyse in a compact way the evolution of particle production with the system size and the origin of a very different system size dependence of the different particles.
nucl-thEPJ Web Conf.(2018)·19 citations
03
Jet substructure modification in a QGP from a multi-scale description of jet evolution with JETSCAPE
Y. Tachibana🇺🇸 · A. Angerami · S. A. Bass · S. Cao · J. Coleman · L. Cunqueiro · T. Dai · L. Du · H. Elfner · D. Everett · W. Fan · R. Fries and 32 other authors
The modification of jet substructure in relativistic heavy-ion collisions is studied using JETSCAPE, a publicly available software package containing a framework for Monte Carlo event generators. Multi-stage jet evolution in JETSCAPE provides an integrated description of jet quenching by combining multiple models, with each becoming active at a different stage of the parton shower evolution. Jet substructure modification due to different aspects of jet quenching is studied using jet shape and jet fragmentation observables. Various combinations of jet energy loss models are exploed, with medium background provided by (2 + 1)-D VISHNU with TRENTo+freestreaming initial conditions. Results reported here are from simulations performed within JETSCAPE framework.
nucl-thhep-phnucl-exPoS(2018)·17 citations
04
Cluster radioactivity of $_{118}^{294}$ Og $_{176}$
Zachary Matheson🇺🇸 · Samuel A. Giuliani🇺🇸 · Witold Nazarewicz🇺🇸 · Jhilam Sadhukhan🇮🇳 · Nicolas Schunck🇺🇸
According to theory, cluster radioactivity becomes an important decay mode in superheavy nuclei. In this work, we predict that the strongly-asymmetric fission, or cluster emission, is in fact the dominant fission channel for $_{118}^{294}$ Og $_{176}$ , which is currently the heaviest synthetic isotope known. Our theoretical approach incorporates important features of fission dynamics, including quantum tunneling and stochastic dynamics up to scission. We show that, despite appreciable differences in static fission properties such as fission barriers and spontaneous fission lifetimes, the prediction of cluster radioactivity in $_{118}^{294}$ Og $_{176}$ is robust with respect to the details of calculations, including the choice of energy density functional, collective inertia, and the strength of the dissipation term.
nucl-thPRC(2019)·57 citations
05
Study of the effect of newly calculated phase space factor on beta-decay half-lives
Jameel-Un Nabi · Mavra Ishfaq · Ovidiu Nitescu · Mihail Mirea · Sabin Stoica
We present results for $β$ -decay half-lives based on a new recipe for calculation of phase space factors recently introduced. Our study includes $f p$ -shell and heavier nuclei of experimental and astrophysical interests. The investigation of the kinematics of some $β$ -decay half-lives is presented, and new phase space factor values are compared with those obtained with previous theoretical approximations. Accurate calculation of nuclear matrix elements is a pre-requisite for reliable computation of $β$ -decay half-lives and is not the subject of this paper. This paper explores if improvements in calculating the $β$ -decay half-lives can be obtained when using a given set of nuclear matrix elements and employing the new values of the phase space factors. Although the largest uncertainty in half-lives computations come from the nuclear matrix elements, introduction of the new values of the phase space factors may improve the comparison with experiment. The new half-lives are systematically larger than previous calculations and may have interesting consequences for calculation of stellar rates.
nucl-thAdv.High Energy Phys.(2019)·2 citations
06
Dynamics of relativistic spin-polarized fluids
Wojciech Florkowski🇵🇱 · Bengt Friman🇩🇪 · Amaresh Jaiswal🇮🇳 · Radoslaw Ryblewski🇵🇱 · Enrico Speranza🇩🇪
We briefly review the foundations of a new relativistic fluid dynamics framework for polarized systems of particles with spin one half. Using this approach we numerically study the dynamics of the spin polarization of a rotating medium resembling the ones created in high-energy heavy-ion collisions.
nucl-thhep-phActa Phys.Polon.Supp.(2019)·2 citations
07
Finding the Scatterers in Hot Quark Soup
Francesco D'Eramo🇮🇹 · Krishna Rajagopal🇺🇸 · Yi Yin🇺🇸
We present a brief report on a thought experiment in which an incident energetic parton traverses a brick of quark-gluon plasma (QGP), see arXiv:1808.03250 for the full report. We calculate the probability of detecting a parton showing up at a large angle with respect to its initial direction due to scattering with the constituents of QGP, using leading order perturbative QCD. We include all relevant channels, including the Rutherford-like channel as considered in early works, and those that are not Rutherford-like but become important at a large angle. The resulting probability distributions contain information about the short distance structure of QGP. Our results provide key theoretical input toward finding the scatterers within the QGP liquid, which in turn is the necessary first step toward using precise, high-statistics, suitably differential measurements of jet modification in heavy ion collisions to study the evolution of the properties of QGP with changing resolution scale.
nucl-thhep-phPoS(2018)·1 citation
08
Interference, spectral momentum correlations, entanglement, and Bell inequality for a trapped interacting ultracold atomic dimer: Analogies with biphoton interferometry
Constantine Yannouleas · Benedikt B. Brandt · Uzi Landman
Elucidating similarities and differences between quantum-optics biphoton interference phenomena and the quantum physics of quasi-one-dimensional double-well optically-trapped ultracold neutral bosonic or fermionic atoms, we show that the analog of the optical biphoton joint-coincidence spectral correlations, studied with massless non-interacting biphotons emanating from EPR-Bell-Bohm single-occupancy sources, corresponds to a distinct contribution in the total second-order momentum correlations of the massive, interacting, and time-evolving ultracold atoms. This single-occupancy contribution can be extracted from the total second-order momentum correlation function measured in time-of-flight experiments, which for the trapped atomic system contains, in general, a double-occupancy, NOON, component. The dynamics of the two-particle system are modeled by a Hubbard Hamiltonian. This partial coincidence spectrum is a cosine-square quantum beating dependent on the difference of the momenta of the two particles, while the corresponding coincidence probability proper, familiar from its role in describing the Hong-Ou-Mandel coincidence dip of overlapping photons, results from an integration over the particle momenta. Because the second-order momentum correlations are mirrored in the time-of-flight spectra in space, our theoretical findings provide impetus for time-of-flight experimental protocols for emulating with (massive) ultracold atoms venerable optical interferometries that use two space-time separated and entangled (massless) photons or double-slit optical sources. The implementation of such developments will facilitate testing of fundamental aspects and enable applications of quantum physics with trapped massive ultracold atoms, that is, investigations of nonlocality and violation of Bell inequalities, entanglement, and quantum information science.
↳ cond-mat.quant-gasnucl-thquant-phPRA(2019)·11 citations
09
Discrepancy in tidal deformability of GW170817 between the Advanced LIGO twin detectors
Tatsuya Narikawa🇯🇵 · Nami Uchikata🇯🇵 · Kyohei Kawaguchi🇯🇵 · Kenta Kiuchi🇯🇵 · Koutarou Kyutoku🇯🇵 · Masaru Shibata🇩🇪 · Hideyuki Tagoshi🇯🇵
We find that the Hanford and Livingston detectors of Advanced LIGO derive a distinct posterior probability distribution of binary tidal deformability tilde{Lambda} of the first binary-neutron-star merger GW170817. By analyzing public data of GW170817 with a nested-sampling engine and the default TaylorF2 waveform provided by the LALInference package, the probability distribution of the binary tidal deformability derived by the LIGO-Virgo detector network turns out to be determined dominantly by the Hanford detector. Specifically, by imposing the flat prior on tidal deformability of individual stars, symmetric 90% credible intervals of tilde{Lambda} are estimated to be 527^{+619}_{-345} with the Hanford detector, 927^{+522}_{-619} with the Livingston detector, and 455^{+668}_{-281} with the LIGO-Virgo detector network. Furthermore, the distribution derived by the Livingston detector changes irregularly when we vary the maximum frequency of the data used in the analysis. This feature is not observed for the Hanford detector. While they are all consistent, the discrepancy and irregular behavior suggest that an in-depth study of noise properties might improve our understanding of GW170817 and future events.
↳ astro-ph.HEgr-qcnucl-thPhys.Rev.Research.(2019)·16 citations
10
Pions near condensation under compact star conditions
Cristian Villavicencio🇨🇱 · Marcelo Loewe🇨🇱 · Alfredo Raya🇲🇽
The behavior of pions is studied in systems where their normal leptonic decay is forbidden. When thermal fluctuations are present, a low decay rate is generated, and as a consequence of lepton recombination, the amount of pions remains almost unaltered. Compact stars conditions are favorable for the formation of such intermediate state of charged pions: near condensation and almost stable, leading to a continuum source of anti-neutrinos. In particular, protoneutron stars could be an scenario where this state of matter is relevant.
↳ hep-phastro-ph.HEnucl-thAstron.Nachr.(2019)·0 citations
11
Centrality dependence of deuteron production in Pb+Pb collisions at 2.76 TeV via hydrodynamics and hadronic afterburner
Dmytro Oliinychenko🇺🇸 · Long-Gang Pang🇺🇸 · Hannah Elfner🇩🇪 · Volker Koch🇺🇸
The deuteron binding energy is only 2.2 MeV. At the same time, its yield in Pb+Pb collisions at $s_{N N} =$ 2.76 TeV corresponds to a thermal yield at the temperature around 155 MeV, which is too hot to keep deuterons bound. This puzzle is not completely resolved yet. In general, the mechanism of light nuclei production in ultra-high energy heavy ion collisions remains under debate. In a previous work [1] we suggest a microscopic explanation of the deuteron production in central ultra-relativistic Pb+Pb collisions, the main mechanism being $π p n \leftrightarrow π d$ reactions in the hadronic phase of the collision. We use a state-of-the-art hybrid approach, combining relativistic hydrodynamics for the hot and dense stage and hadronic transport for a later, more dilute stage. Deuteron rescattering in the hadronic stage is implemented explicitly, using its experimentally measured vacuum cross-sections. In these proceedings we extend our previous work to non-central collisions, keeping exactly the same methodology and parameters. We find that our approach leads to a good description of the measured deuteron transverse momentum spectra at centralities up to 40%, and underestimates the amount of deuterons at low transverse momentum at higher centralities. Nevertheless, the coalescence parameter $B_{2}$ , measured by ALICE collaboration, is reproduced well in our approach even for peripheral collisions.
↳ hep-phnucl-thMDPI Proc.(2019)·13 citations
12
Dynamically generated magnetic moment in the Wigner-function formalism
Shijun Mao🇨🇳 · Dirk H. Rischke🇩🇪
We study how the mass and magnetic moment of the quarks are dynamically generated in nonequilibrium quark matter. We derive the equal-time transport and constraint equations for the quark Wigner function in a magnetized quark model and solve them in the semi-classical expansion. The quark mass and magnetic moment are self-consistently coupled to the Wigner function and controlled by the kinetic equations. While the quark mass is dynamically generated at the classical level, the quark magnetic moment is a pure quantum effect, induced by the quark spin interaction with the external magnetic field.
↳ hep-thhep-phnucl-thPLB(2019)·18 citations
13
Impact of the inelastic proton -- nucleus cross section on the prompt neutrino flux
A. V. Giannini🇧🇷 · V. P. Goncalves🇧🇷
The description of the inelastic proton -- nucleus cross section at very high energies is still an open question. The current theoretical uncertainty has direct impact on the predictions of the cosmic ray and neutrino physics observables. In this paper we consider different models for the treatment of $σ_{in e l}^{p A}$ , compare its predictions at ultrahigh cosmic ray energies and estimate the prompt neutrino flux at the neutrino energies that have been probed by the IceCube Observatory. We demonstrate that depending of the model used to describe $σ_{in e l}^{p A}$ , the predictions for the prompt neutrino flux can differ by a factor of order of three. Such result demonstrate the importance of a precise measurement of the inelastic proton -- nucleus cross section at high energies.
↳ hep-phnucl-thEPJC(2019)·1 citation
14
Future physics opportunities for high-density QCD at the LHC with heavy-ion and proton beams
Z. Citron🇮🇱 · A. Dainese🇮🇹 · J.F. Grosse-Oetringhaus🇨🇭 · J.M. Jowett🇨🇭 · Y.-J. Lee🇺🇸 · U.A. Wiedemann🇨🇭 · M. Winn (editors)🇫🇷 · A. Andronic🇩🇪 · F. Bellini🇨🇭 · E. Bruna🇮🇹 · E. Chapon🇨🇭 · H. Dembinski🇩🇪 and 173 other authors
The future opportunities for high-density QCD studies with ion and proton beams at the LHC are presented. Four major scientific goals are identified: the characterisation of the macroscopic long wavelength Quark-Gluon Plasma (QGP) properties with unprecedented precision, the investigation of the microscopic parton dynamics underlying QGP properties, the development of a unified picture of particle production and QCD dynamics from small (pp) to large (nucleus--nucleus) systems, the exploration of parton densities in nuclei in a broad ( $x$ , $Q^{2}$ ) kinematic range and the search for the possible onset of parton saturation. In order to address these scientific goals, high-luminosity Pb-Pb and p-Pb programmes are considered as priorities for Runs 3 and 4, complemented by high-multiplicity studies in pp collisions and a short run with oxygen ions. High-luminosity runs with intermediate-mass nuclei, for example Ar or Kr, are considered as an appealing case for extending the heavy-ion programme at the LHC beyond Run 4. The potential of the High-Energy LHC to probe QCD matter with newly-available observables, at twice larger center-of-mass energies than the LHC, is investigated.
↳ hep-phhep-exnucl-exnucl-thCERN Yellow Rep.Monogr.(2019)·425 citations
15
Using world charged pion--nucleus scattering data to constrain an intranuclear cascade model
E. S. Pinzon Guerra🇨🇦 · C. Wilkinson🇨🇭 · S. Bhadra🇨🇦 · S. Bolognesi🇫🇷 · J. Calcutt🇺🇸 · P. de Perio🇨🇦 · S. Dolan🇫🇷 · T. Feusels🇨🇦 · G.A. Fiorentini🇨🇦 · Y. Hayato🇯🇵 · K. Ieki🇯🇵 · K. Mahn🇺🇸 and 10 other authors
The NEUT intranuclear cascade model is described and fit to a large body of \pipm--nucleus scattering data. Methods are developed to deal with deficiencies in the available historical data, and robust uncertainty estimates are produced. The results are compared to a variety of simulation packages, and the data itself. This work provides a method for tuning Final State Interaction models, which are of particular interest to neutrino experiments that operate in the few-GeV energy region, and provides results which can be used directly by the T2K and Super-Kamiokande collaborations, for whom NEUT is the primary simulation package.
↳ hep-exnucl-exnucl-thPRD(2019)·78 citations
16
Helicity Methods for High Multiplicity Subleading Soft and Collinear Limits
Arindam Bhattacharya🇺🇸 · Ian Moult🇺🇸 · Iain W. Stewart🇺🇸 · Gherardo Vita🇺🇸
The factorization of multi-leg gauge theory amplitudes in the soft and collinear limits provides strong constraints on the structure of amplitudes, and enables efficient calculations of multi-jet observables at the LHC. There is significant interest in extending this understanding to include subleading powers in the soft and collinear limits. While this has been achieved for low point amplitudes, for higher point functions there is a proliferation of variables and more complicated phase space, making the analysis more challenging. By combining the subleading power expansion of spinor-helicity variables in collinear limits with consistency relations derived from the soft collinear effective theory, we show how to efficiently extract the subleading power leading logarithms of $N$ -jet event shape observables directly from known spinor-helicity amplitudes. At subleading power, we observe the presence of power law singularities arising solely from the expansion of the amplitudes, which for hadron collider event shapes lead to the presence of derivatives of parton distributions. The techniques introduced here can be used to efficiently compute the power corrections for $N$ -jettiness subtractions for processes involving jets at the LHC.
↳ hep-phhep-thnucl-thJHEP(2019)·43 citations

Affiliations

first authorsco-authorsvia INSPIRE