Nuclear Theory·nucl-th

Friday·April 7, 2023

6 papers—3 primary·3 cross-listed

01
Asymptotic normalization coefficients of alpha-particle removal from $^{16}$ O( $3^{-}, 2^{+}, 1^{-}$ )
L. D. Blokhintsev · A. S. Kadyrov · A. M. Mukhamedzhanov · D. A. Savin
Asymptotic normalization coefficients (ANC) determine the overall normalization of cross sections of peripheral radiative capture reactions. In a recent paper [Blokhintsev et al., Eur. Phys. J. A 58, 257 (2022)], we considered the ANC $C_{0}$ for the virtual decay $^{16}$ O $(0^{+}; 6.05$ MeV) $\to α +^{12}$ C(g.s.). In the present paper, which can be regarded as a continuation of the previous, we treat the ANCs $C_{l}$ for the vertices $^{16}$ O $(J^{π}) \to α +^{12}$ C(g.s.) corresponding to the other three bound excited states of $^{16}$ O ( $J^{π} = 3^{-}$ , $2^{+}$ , $1^{-}$ , $l = J$ ). ANCs $C_{l}$ ( $l = 3, 2, 1$ ) are found by analytic continuation in energy of the $α^{12}$ C $l$ -wave partial scattering amplitudes, known from the phase-shift analysis of experimental data, to the pole corresponding to the $^{16}$ O bound state and lying in the unphysical region of negative energies. To determine $C_{l}$ , the scattering data are approximated by the sum of polynomials in energy in the physical region and then extrapolated to the pole. For a more reliable determination of the ANCs, various forms of functions expressed in terms of phase shifts were used in analytical approximation and subsequent extrapolation.
nucl-thastro-ph.SRnucl-ex0 citations
02
Mitigating Green's function Monte Carlo signal-to-noise problems using contour deformations
Gurtej Kanwar🇨🇭 · Alessandro Lovato🇺🇸 · Noemi Rocco🇺🇸 · Michael Wagman🇺🇸
The Green's function Monte Carlo (GFMC) method provides accurate solutions to the nuclear many-body problem and predicts properties of light nuclei starting from realistic two- and three-body interactions. Controlling the GFMC fermion-sign problem is crucial, as the signal-to-noise ratio decreases exponentially with Euclidean time, requiring significant computing resources. Inspired by similar scenarios in lattice quantum field theory and spin systems, in this work, we employ integration contour deformations to improve the GFMC signal-to-noise ratio. Machine learning techniques are used to select optimal contours with minimal variance from parameterized families of deformations. As a proof of principle, we consider the deuteron binding energies and Euclidean density response functions. We only observe mild signal-to-noise improvement for the binding energy case. On the other hand, we achieve an order of magnitude reduction of the variance for Euclidean density response functions, paving the way for computing electron- and neutrino-nucleus cross-sections of larger nuclei.
nucl-thhep-lathep-phPRC(2024)·8 citations
03
Glasma properties in small proper time expansion
Margaret E. Carrington🇨🇦 · Wade N. Cowie🇨🇦 · Bryce T. Friesen🇨🇦 · Stanislaw Mrowczynski🇵🇱 · Doug Pickering🇨🇦
In a series of works by two of us, various characteristics of the glasma from the earliest phase of relativistic heavy-ion collisions have been studied using a proper time expansion. These characteristics include: energy density, longitudinal and transverse pressures, collective flow, angular momentum and parameters of jet quenching. In this paper we extend the proper time interval where our results are reliable by working at higher order in the expansion. We also generalize our previous study of jet quenching by extending our calculations to consider inhomogeneous glasma. Inhomogeneities are an important aspect of physically realistic systems that are difficult to include in calculations and are frequently ignored.
nucl-thhep-phPRC(2023)·9 citations
04
Electric-charge-dependent directed flow splitting of produced quarks in Au+Au collisions
STAR Collaboration
We report directed flow ( $v_{1}$ ) of multistrange baryons ( $Ξ$ and $Ω$ ) and improved $v_{1}$ data for $K^{-}$ , $p ˉ$ , $Λ ˉ$ and $ϕ$ in Au+Au collisions at $s_{NN} =$ 27 and 200 GeV from the STAR experiment at the Relativistic Heavy Ion Collider (RHIC). We focus on particles whose constituent quarks are not transported from the incoming nuclei but instead are produced in the collisions. At intermediate impact parameters, we examine quark coalescence behavior for particle combinations with identical quark content, and search for any departure from this behavior (``splitting'') for combinations having non-identical quark content. Under the assumption of quark coalescence for produced quarks, the splitting strength appears to increase with the electric charge difference of the constituent quarks in the combinations, consistent with electromagnetic effect expectations.
↳ nucl-exhep-phnucl-thPLB(2025)·12 citations
05
Possible molecular dibaryons with $csss q q$ quarks and their baryon-antibaryon partners
Shu-Yi Kong🇨🇳 · Jun-Tao Zhu🇨🇳 · Jun He🇨🇳
In this work, we systematically investigate the charmed-strange dibaryon systems with $csss q q$ quarks and their baryon-antibaryon partners from the interactions $Ξ_{c}^{(^{'}, *)} Ξ^{(*)}$ , $Ω_{c}^{(*)} Λ$ , $Ω_{c}^{(*)} Σ^{(*)}$ , $Λ_{c} Ω$ and $Σ_{c}^{(*)} Ω$ and their baryon-antibaryon partners from interactions $Ξ_{c}^{(^{'}, *)} Ξ ˉ^{(*)}$ , $Ω_{c}^{(*)} Λ ˉ$ , $Ω_{c}^{(*)} Σ ˉ^{(*)}$ , $Λ_{c} Ω ˉ$ and $Σ_{c}^{(*)} Ω ˉ$ . The potential kernels are constructed with the help of effective Lagrangians under SU(3), heavy quark, and chiral symmetries to describe these interactions. To search for possible molecular states, the kernels are inserted into the quasipotential Bethe-Salpeter equation, which is solved to find poles from scattering amplitude. The results suggest that 36 and 24 bound states can be found in the baryon-baryon and baryon-antibaryon interactions, respectively. However, much large values of parameter $α$ are required to produce the bound states from the baryon-antibaryon interactions, which questions the existence of these bound states. Possible coupled-channel effect are considered in the current work to estimate the couplings of the molecular states to the channels considered.
↳ hep-phnucl-thEPJC(2023)·7 citations
06
B meson production in Pb+Pb at 5.02 ATeV at LHC: estimating the diffusion coefficient in the infinite mass limit
Maria Lucia Sambataro (1 and 2)🇮🇹 · Vincenzo Minissale (2)🇮🇹 · Salvatore Plumari (1 and 2)🇮🇹 · Vincenzo Greco (1 and 2) ((1) Department of Physics and Astronomy 'E. Majorana', University of Catania, Via S. Sofia 64, 1-95123 Catania, Italy, (2) Laboratori Nazionali del Sud, INFN-LNS, Via S. Sofia 62, I-95123 Catania, Italy)🇮🇹
In the last decade a Quasi-Particle Model (QPM) has been developed to study charm quark dynamics in ultra-relativistic heavy-ion collisions supplying a satisfactory description of the main observables for $D$ meson and providing an estimate of the space-diffusion coefficient $D_{s} (T)$ from the phenomenology. In this paper, we extend the approach to bottom quarks describing their propagation in the quark-gluon plasma within an event-by-event full Boltzmann transport approach followed by a coalescence plus fragmentation hadronization. We find that QPM approach is able to correctly predict the first available data on $R_{AA} (p_{T})$ and $v_{2} (p_{T})$ of single-electron from B decays without any parameter modification w.r.t. the charm. We show also predictions for centralities where data are not yet available for both $v_{2} (p_{T})$ and $v_{3} (p_{T})$ . Moreover, we discuss the significant breaking of the expected scaling of the thermalization time $τ_{t h}$ with $M_{Q} / T$ , discussing the evolution with mass of $D_{s} (T)$ to better assess the comparison to lQCD calculations. We find that at $T = T_{c}$ charm quark $D_{s} (T)$ is about a factor of 2 larger than the asymptotic value for $M \to \infty$ , while bottom $D_{s} (T)$ is only a $20 - 25%$ higher. This implies a $D_{s} (T)$ which is consistent within the current uncertainty to the most recent lattice QCD calculations with dynamical quarks for $M \to \infty$ .
↳ hep-phnucl-thPLB(2024)·35 citations

Affiliations

first authorsco-authorsvia INSPIRE

Asymptotic normalization coefficients of alpha-particle removal from 16O(3−,2+,1−)

Mitigating Green's function Monte Carlo signal-to-noise problems using contour deformations

Glasma properties in small proper time expansion

Electric-charge-dependent directed flow splitting of produced quarks in Au+Au collisions

Possible molecular dibaryons with csssqq quarks and their baryon-antibaryon partners

B meson production in Pb+Pb at 5.02 ATeV at LHC: estimating the diffusion coefficient in the infinite mass limit

Affiliations

Asymptotic normalization coefficients of alpha-particle removal from $^{16}$ O( $3^{-}, 2^{+}, 1^{-}$ )

Possible molecular dibaryons with $csss q q$ quarks and their baryon-antibaryon partners