Nuclear Theory·nucl-th

Tuesday·September 1, 2020

19 papers—9 primary·10 cross-listed

10
[Submitted on 27 Aug 2020] (cross-list from hep-ph)
Triple-X and beyond: hadronic systems of three and more X(3872)
Lorenzo Contessi🇫🇷 · Johannes Kirscher🇬🇧 · Manuel Pavon Valderrama🇨🇳
The $X (3872)$ resonance has been conjectured to be a $J^{P C} = 1^{++}$ charm meson-antimeson two-body molecule. Meanwhile, there is no experimental evidence for larger, few-body compounds of multiple charm meson-antimeson pairs which would resemble larger molecules or nuclei. Here, we investigate such multi-meson states to the extent of what can be deduced theoretically from essentials of the interaction between uncharged $D^{0}$ and $D^{* 0}$ mesons. From a molecular $X (3872)$ , we predict a $4 X$ ( $4^{++}$ ) octamer with a binding energy \mbox{ $B_{4 X} > 2.08 MeV$ ,} assuming a $D^{* 0} D ˉ^{0}$ system close to the unitary limit (as suggested by the mass of the $X (3872)$ ). If we consider heavy-quark spin symmetry explicitly, the $D^{* 0} D ˉ^{* 0}$ ( $2^{++}$ ) system is close to unitarity, too. In this case, we predict a bound $3 X$ ( $3^{++}$ ) hexamer with $B_{3 X} > 2.29 MeV$ and a more deeply bound $4 X$ octamer with $B_{4 X} > 11.21 MeV$ . These results exemplify with hadronic molecules a more general phenomenon of equal-mass two-species Bose systems comprised of equal number of either type: the emergence of unbound four- and six-boson clusters in the limit of a short-range two-body interaction which acts only between bosons of different species. Finally, we also study the conditions under which a $2 X$ ( $2^{++}$ ) tetramer might form.
Comments:
7 pages, 3 figures, corresponds to the published version
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2008.12268 [pdf]
PRD(2021)·4 citations
11
[Submitted on 28 Aug 2020] (cross-list from astro-ph.HE)
Combining Electromagnetic and Gravitational-Wave Constraints on Neutron-Star Masses and Radii
Mohammad Al-Mamun · Andrew W. Steiner · Joonas Nättilä · Jacob Lange · Richard O'Shaughnessy · Ingo Tews · Stefano Gandolfi · Craig Heinke · Sophia Han
We perform a joint Bayesian inference of neutron-star mass and radius constraints based on GW170817, observations of quiescent low-mass X-ray binaries (QLMXBs), photospheric radius expansion X-ray bursts (PREs), and X-ray timing observations of J0030+0451. With this data set, the form of the prior distribution still has an impact on the posterior mass-radius (MR) curves and equation of state (EOS), but this impact is smaller than recently obtained when considering QLMXBs alone. We analyze the consistency of the electromagnetic data by including an "intrinsic scattering" contribution to the uncertainties, and find only a slight broadening of the posteriors. This suggests that the gravitational-wave and electromagnetic observations of neutron-star structure are providing a consistent picture of the neutron-star mass-radius curve and the EOS.
Comments:
6 pages, 4 figures and supplemental material
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Theory (nucl-th)
arXiv:
2008.12817 [pdf]
PRL(2021)·111 citations
12
[Submitted on 29 Aug 2020] (cross-list from physics.atom-ph)
Nonlinear optical effects in a nucleus
Tao Li🇨🇳 · Xu Wang🇨🇳
Intense laser technologies generate light with unprecedented and growing intensities. The possibility emerges that a nucleus responds nonlinearly to an intense light field, pointing to a yet little explored research area of nuclear nonlinear optics. We consider two-photon and three-photon absorption (with subsequent disintegration) processes of the deuteron, the simplest and the most fundamental nontrivial nucleus, as prototypes of nuclear nonlinear optical effects. Quantitative calculations are performed on these processes and novel observable effects are predicted.
Subjects:
Atomic Physics (physics.atom-ph); Nuclear Theory (nucl-th)
arXiv:
2008.12956 [pdf]
J.Phys.G(2021)·6 citations
13
[Submitted on 31 Aug 2020] (cross-list from hep-ph)
Gradient tomography of jet quenching in high-energy heavy-ion collisions
Yayun He🇨🇳 · Longgang Pang🇨🇳 · Xin-Nian Wang🇨🇳
We illustrate with both a Boltzmann diffusion equation and full simulations of jet propagation in heavy-ion collisions within the Linear Boltzmann Transport (LBT) model that the spatial gradient of the jet transport coefficient perpendicular to the propagation direction can lead to a drift and asymmetry in the transverse momentum distribution. Such an asymmetry depends on both the spatial position along the transverse gradience and the propagating length. It can be used to localize the initial jet production positions for more detailed studies of jet quenching and properties of the quark-gluon plasma in heavy-ion collisions.
Comments:
4 pages in Latex format for POS with 4 PDF figures, prepared for publication in the proceedings of Hard Probes 2020 conference, 1-6 June 2020, Austin, Texas
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2008.13304 [pdf]
PoS(2021)·1 citation
14
[Submitted on 31 Aug 2020] (cross-list from hep-ph)
Near-threshold photoproduction of $J / ψ$ in two-gluon exchange model
Fancong Zeng🇨🇳 · Xiao-Yun Wang🇨🇳 · Li Zhang🇨🇳 · Ya-Ping Xie🇨🇳 · Rong Wang🇨🇳 · Xurong Chen🇨🇳
The near-threshold photoproduction of $J / ψ$ is regarded as one golden process to unveil the nucleon mass structure, pentaquark state involving the charm quarks, and the poorly constrained gluon distribution of the nucleon at large $x$ ( $> 0.1$ ). In this paper, we present an analysis of the current experimental data under a two-gluon exchange model, which shows a good consistency. Using a parameterized function form with three free parameters, we have determined the nucleonic gluon distribution at the $J / ψ$ mass scale. Moreover, we predict the differential cross section of the electroproduction of $J / ψ$ as a function of the invariant mass of the final hadrons $W$ , at EicC, as a practical application of the model and the obtained gluon distribution. According to our estimation, thousands of $J / ψ$ events can be detected per year on EicC near the threshold. Therefore, the relevant experimental measurements are suggested to be carried out on EicC.
Comments:
6 pages, 7 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2008.13439 [pdf]
EPJC(2020)·21 citations
15
[Submitted on 31 Aug 2020] (cross-list from hep-ph)
Evidence of shadowing in inelastic nucleon-nucleon cross section
Kari J. Eskola🇫🇮 · Ilkka Helenius🇫🇮 · Mikko Kuha🇫🇮 · Hannu Paukkunen
The Glauber modeling plays a key role in centrality-dependent measurements of heavy-ion collisions. A central input parameter in Glauber models is the inelastic nucleon-nucleon cross section $σ_{nn}^{inel}$ which is nearly always taken from proton-proton measurements. At the LHC energies $σ_{nn}^{inel}$ depends on the QCD dynamics at small $x$ and low interaction scales where the shadowing/saturation phenomena are expected to become relatively more important for larger nuclei than for the proton. Thus, $σ_{nn}^{inel}$ e.g. in Pb+Pb collisions may well be lower than what is seen in proton-proton collisions. In this talk, we demonstrate how to use the recent $W^{\pm}$ and $Z$ measurements as a "standard candle" to extract $σ_{nn}^{inel}$ in Pb+Pb collisions. Our analysis -- built on the ATLAS data, state-of-the-art NNLO QCD calculations and nuclear PDFs -- indicate that at the LHC energies $σ_{nn}^{inel}$ in Pb+Pb collisions is suppressed relative to the proton-proton measurements by tens of percents. We demonstrate that this is in line with expectations from nuclear PDFs.
Comments:
5 pages, 4 figures, to appear in the proceedings of the 10th International Conference on Hard and Electromagnetic Probes of High-Energy Nuclear Collisions, 1 - 5 June 2020, Austin, Texas, USA
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2008.13448 [pdf]
PoS(2021)·2 citations
16
[Submitted on 31 Aug 2020] (cross-list from hep-ph)
$X_{0, 1}$ (2900) and $(D^{-} K^{+})$ invariant mass from QCD Laplace sum rules at NLO
R.M. Albuquerque🇧🇷 · S. Narison🇫🇷 · D. Rabetiarivony🇲🇬 · G. Randriamanatrika🇲🇬
We revisit, improve and complete some recent estimates of the $0^{+}$ and $1^{-}$ open charm $(c ˉ d ˉ) (u s)$ tetraquarks and the corresponding molecules masses and decay constants from QCD spectral sum rules (QSSR) by using QCD Laplace sum rule (LSR) within stability criteria where the factorised perturbative NLO corrections and the contributions of quark and gluon condensates up to dimension-6 in the OPE are included. We confront our results with the $D^{-} K^{+}$ invariant mass recently reported by LHCb from $B^{+} \to D^{+} (D^{-} K^{+})$ decays. We expect that the bump near the $D^{-} K^{+}$ threshold can be originated from the $0^{++} (D^{-} K^{+})$ molecule and/or $D^{-} K^{+}$ scattering. The prominent $X_{0}$ (2900) scalar peak and the bump $X_{J} (3150)$ (if $J = 0$ ) can emerge from a {\it minimal mixing model}, with a tiny mixing angle $θ_{0} ≃ (5.2 \pm 1.9)^{0}$ , between a scalar {\it Tetramole} ( $T_{M}_{0}$ ) (superposition of nearly degenerated hypothetical molecules and compact tetraquarks states with the same quantum numbers) having a mass $M_{T_{M}_{0}}$ =2743(18) MeV and the first radial excitation of the $D^{-} K^{+}$ molecule with mass $M_{(D K)_{1}} = 3678 (310)$ MeV. In an analogous way, the $X_{1}$ (2900) and the $X_{J} (3350)$ (if $J = 1$ ) could be a mixture between the vector {\it Tetramole} $(T_{M}_{1})$ with a mass $M_{T_{M}_{1}} = 2656 (20)$ MeV and its first radial excitation having a mass $M_{(T_{M}_{1})_{1}} = 4592 (141)$ MeV with an angle $θ_{1} ≃ (9.1 \pm 0.6)^{0}$ . A (non)-confirmation of the previous {\it minimal mixing models} requires an experimental identification of the quantum numbers of the bumps at 3150 and 3350 MeV.
Comments:
28 pages, 15 Figures, 5 Tables - Version to appear in Nuclear Physics A after some minor corrections on proofs
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2008.13463 [pdf]
NPA(2021)·58 citations
17
[Submitted on 31 Aug 2020] (cross-list from hep-ph)
Cosmological particle creation in the little bang
S.V. Akkelin🇺🇦
Particle production by expanding in the future light cone scalar quantum field is studied by assuming that the initial state is associated with the quasiequilibrium statistical operator corresponding to fluid dynamics. We calculate particle production from a longitudinally boost-invariant expanding quantum field designed as a simple but reliable model for the central rapidity region of a relativistic collision. Exact diagonalization of the model is performed by introducing a notion of quasiparticles.
Comments:
17 pages
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2008.13606 [pdf]
PRD(2021)·6 citations
18
[Submitted on 31 Aug 2020] (cross-list from astro-ph.HE)
Medium modifications for light and heavy nuclear clusters in simulations of core collapse supernovae -- Impact on equation of state and weak interactions
Tobias Fischer · Stefan Typel · Gerd Röpke · Niels-Uwe F. Bastian · Gabriel Martínez-Pinedo
The present article investigates the role of heavy nuclear clusters and weakly bound light nuclear clusters based on a newly developed equation of state for core collapse supernova studies. A novel approach is brought forward for the description of nuclear clusters, taking into account the quasiparticle approach and continuum correlations. It demonstrates that the commonly employed nuclear statistical equilibrium approach, based on non-interacting particles, for the description of light and heavy clusters becomes invalid for warm nuclear matter near the saturation density. This has important consequences for studies of core collapse supernovae. To this end, we implement this nuclear equation of state provided for arbitrary temperature, baryon density and isospin asymmetry, to spherically symmetric core collapse supernova simulations in order to study the impact on the dynamics as well as on the neutrino emission. For the inclusion of a set of weak processes involving light clusters the rate expressions are derived, including medium modifications at the mean field level. A substantial impact from the inclusion of a variety of weak reactions involving light clusters on the post bounce dynamics nor on the neutrino emission could not be found.
Comments:
24 pages, 9 figures
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
arXiv:
2008.13608 [pdf]
PRC(2020)·34 citations
19
[Submitted on 27 Aug 2020] (cross-list from hep-ph)
Study of Transverse Spherocity and Azimuthal Anisotropy in Pb-Pb collisions at $s_{NN}$ = 5.02 TeV using A Multi-Phase Transport Model
Neelkamal Mallick🇮🇳 · Raghunath Sahoo🇮🇳 · Sushanta Tripathy🇲🇽 · Antonio Ortiz🇲🇽
Transverse spherocity is an event shape observable having a very unique capability to separate the events based on their geometrical shapes. Recent results from experiments at the LHC suggest that transverse spherocity is an important event classifier in small collision systems. In this work, we use transverse spherocity for the first time in heavy-ion collisions and perform an extensive study on azimuthal anisotropy of charged particles produced in Pb-Pb collisions at $s_{NN} = 5.02$ TeV using A Multi-Phase Transport Model (AMPT). The azimuthal anisotropy is estimated using the 2-particle correlation method, which suppresses the non-flow effects significantly with an appropriate pseudorapidity gap of particle pairs. The results from AMPT are compared with estimations from PYTHIA8 (Angantyr) model and it is found that with the chosen pseudorapidity gap the residual non-flow effects become negligible. We found that the high spherocity events have nearly zero elliptic flow while low spherocity events contribute significantly to elliptic flow of spherocity-integrated events. Our studies indicate that using transverse spherocity in heavy-ion collisions, one can enhance and/or suppress the collective effects.
Comments:
Same as the published version. arXiv admin note: text overlap with arXiv:2001.06849
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2008.13616 [pdf]
J.Phys.G(2021)·35 citations

Affiliations

first authorsco-authorsvia INSPIRE