Nuclear Theory·nucl-th

Thursday·July 29, 2021

12 papers—6 primary·6 cross-listed

01
[Submitted on 27 Jul 2021]
Kaon and pion maximal emission times extraction from the femtoscopy analysis of $5.02 A$ TeV LHC collisions within the integrated hydrokinetic model
V. M. Shapoval🇺🇦 · Yu. M. Sinyukov🇺🇦
A simple method for the extraction of the times of maximal emission for kaons and pions using the combined fitting of their transverse momentum spectra and the longitudinal interferometry radii dependencies on the pair transverse mass $m_{T}$ is applied to Pb+Pb collisions at the LHC energy $s_{N N} = 5.02$ TeV. The method is based on the analytical formulas, that were earlier successfully utilized in the studies of Pb+Pb collisions at $s_{N N} = 2.76$ TeV. To test the method, the spectra, radii and particle radiation picture are calculated within the integrated hydrokinetic model (iHKM), that includes all the stages of the matter evolution in high-energy A+A collisions: the system's formation, its thermalization, viscous hydrodynamics evolution, particlization and subsequent hadronic cascade. The model describes and predicts well already published LHC data in "soft physics? kinematic region. Thus, the fitting results for maximal emission times of kaons and pions are compared to the approximate maximal emission time values, estimated based on the emission function plots, obtained in iHKM. The developed simple method is intended for use in experimental analysis of femtoscopy data in relativistic A+A collisions.
Comments:
17 pages, 10 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2107.13089 [pdf]
NPA(2021)·7 citations
02
[Submitted on 28 Jul 2021]
Electromagnetic interaction of low transverse momentum electrons and positrons with heavy nuclei in ultra-peripheral ultra-relativistic heavy-ion collisions
Katarzyna Mazurek🇵🇱 · Mariola Kłusek-Gawenda🇵🇱 · Antoni Szczurek🇵🇱
The photon-photon interaction in ultra-relativistic heavy-ion collision is a source of the $(e^{+}, e^{-})$ pairs. The photon-photon fusion leads the lepton creation in the broad configuration space around "collision" point. Those created close to heavy nuclei may undergo strong interaction with them. The impact parameter space distribution of electrons and positrons are calculated within the b-space EPA model of such collisions. The evolution due to the electromagnetic interaction of $(e^{+}, e^{-})$ with nuclei is studied, and the distortion of rapidity and transverse momentum distributions are shown. We show first exploratory results for the reaction Pb+Pb at $s_{N N} =$ 17.3 GeV (SPS) and 200 GeV (RHIC) energies. We provide results for selected creation points and when integrating over their position as dictated by the $b$ -space EPA model. We observe strong effects at low transverse momenta, so far not measured regions of the phase space. In particular, we predict a possible sizeable accumulation of electrons with rapidities close to the beam rapidity. The EM effects lead to asymmetry in the production of electrons and positrons.
Comments:
30 pages, 20 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2107.13239 [pdf]
EPJA(2022)·5 citations
03
[Submitted on 28 Jul 2021]
Impact of the leading-order short-range nuclear matrix element on the neutrinoless double-beta decay of medium-mass and heavy nuclei
Lotta Jokiniemi🇪🇸 · Pablo Soriano🇪🇸 · Javier Menéndez🇪🇸
We evaluate the leading-order short-range nuclear matrix element for the neutrinoless double-beta ( $0 ν β β$ ) decay of the nuclei most relevant for experiments, including $^{76}$ Ge, $^{100}$ Mo, $^{130}$ Te and $^{136}$ Xe. In our calculations, performed with the nuclear shell model and proton-neutron quasiparticle random-phase approximation (pnQRPA) methods, we estimate the coupling of this term by the contact charge-independence-breaking coupling of various nuclear Hamiltonians. Our results suggest a significant impact of the short-range matrix element, which is about $15% - 50%$ and $30% - 80%$ of the standard $0 ν β β$ -decay long-range matrix element for the shell model and pnQRPA, respectively. Combining the full matrix elements with the results from current $0 ν β β$ -decay experiments we find that, if both matrix elements carry the same sign, these searches move notably toward probing the inverted mass ordering of neutrino masses.
Comments:
9 pages, 3 figures, 2 tables; Fixed sign error in Eq. (5)
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2107.13354 [pdf]
PLB(2021)·70 citations
04
[Submitted on 28 Jul 2021]
Charged pion production from Au + Au collisions at $s_{N N} = 2.4$ GeV in the Relativistic Vlasov-Uehling-Uhlenbeck model
Kyle Godbey🇺🇸 · Zhen Zhang🇨🇳 · Jeremy W. Holt🇺🇸 · Che Ming Ko🇺🇸
Using the isospin-dependent relativistic Vlasov-Uehling-Uhlenbeck (RVUU) model, we study charged pion ( $π^{\pm}$ ) production in Au+Au collisions at $s_{N N} =$ 2.4 GeV. By fitting the density dependence of the $Δ$ resonance production cross section in nuclear medium to reproduce the experimental $π^{\pm}$ multiplicities measured by the HADES Collaboration, we obtain a good description of the rapidity distributions and transverse momentum spectra of $π^{\pm}$ in collisions at various centralities. Some shortcomings in the description of $π^{\pm}$ production may indicate the need for including the strong potential on $π^{\pm}$ in RVUU, which is at present absent. We also calculate the proton rapidity distribution in the most central collisions and compare with the coalescence invariant proton rapidity distribution extracted from preliminary HADES data.
Comments:
7 pages, 5 figures, version to appear in PLB
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2107.13384 [pdf]
PLB(2022)·11 citations
05
[Submitted on 28 Jul 2021]
Self-learning Emulators and Eigenvector Continuation
Avik Sarkar🇺🇸 · Dean Lee🇺🇸
Emulators that can bypass computationally expensive scientific calculations with high accuracy and speed can enable new studies of fundamental science as well as more potential applications. In this work we discuss solving a system of constraint equations efficiently using a self-learning emulator. A self-learning emulator is an active learning protocol that can be used with any emulator that faithfully reproduces the exact solution at selected training points. The key ingredient is a fast estimate of the emulator error that becomes progressively more accurate as the emulator is improved, and the accuracy of the error estimate can be corrected using machine learning. We illustrate with three examples. The first uses cubic spline interpolation to find the solution of a transcendental equation with variable coefficients. The second example compares a spline emulator and a reduced basis method emulator to find solutions of a parameterized differential equation. The third example uses eigenvector continuation to find the eigenvectors and eigenvalues of a large Hamiltonian matrix that depends on several control parameters.
Comments:
6 + 5 pages (main + supplemental), 5 + 7 figures (main + supplemental), additional discussion, references, and examples added
Subjects:
Nuclear Theory (nucl-th); Machine Learning (cs.LG); cs.NA (cs.NA); High Energy Physics — Lattice (hep-lat); math.NA (math.NA)
arXiv:
2107.13449 [pdf]
PRResearch(2022)·33 citations
06
[Submitted on 26 Jul 2021]
Estimating Microscopic Nuclear Data by Compact Star Observations
Balázs Endre Szigeti🇭🇺 · Gergely Gábor Barnaföldi🇭🇺 · Péter Pósfay🇭🇺 · Antal Jakovác🇭🇺
We studied recent observation data of pulsar masses and radii of PSR J0740 $+$ 6620, PSR J0348 $+$ 0432, and PSR J1614 $-$ 2230 from different measurements, based on the extended version of $σ$ - $ω$ model. Throughout our analysis, we assumed that these pulsars are maximal-mass compact stars, thus we applied the core approximation. Based on the linear relation between the microscopic and macroscopic parameters of compact stars evaluated by our model, we estimated the average Landau mass $m_{L} = 752.4 6_{- 42.5}^{+ 49.1}$ MeV and compressibility $K = 261. 7_{- 28.0}^{+ 57.2}$ MeV.
Comments:
4 paghes 1 table, 1 figue. arXiv admin note: substantial text overlap with arXiv:2006.03710
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2107.13476 [pdf]
EPJ Web Conf.(2022)·2 citations
07
[Submitted on 27 Jul 2021] (cross-list from hep-ph)
Measurement of Bell-type inequalities and quantum entanglement from $Λ$ -hyperon spin correlations at high energy colliders
Wenjie Gong🇺🇸 · Ganesh Parida🇺🇸 · Zhoudunming Tu🇺🇸 · Raju Venugopalan🇺🇸
Spin correlations of $Λ$ -hyperons embedded in the QCD strings formed in high energy collider experiments provide unique insight into their locality and entanglement features. We show from general considerations that while the Clauser-Horne-Shimony-Holt inequality is less stringent for such states, they provide a benchmark for quantum-to-classical transitions induced by varying i) the associated hadron multiplicity, ii) the spin of nucleons, iii) the separation in rapidity between pairs, and iv) the kinematic regimes accessed. These studies also enable the extraction of quantitative measures of quantum entanglement. We first explore such questions within a simple model of a QCD string composed of singlets of two partial distinguishable fermion flavors and compare analytical results to those obtained on quantum hardware. We further discuss a class of spin Hamiltonians that model the dynamics of $Λ$ spin correlations. Prospects for extracting quantum features of QCD strings from hyperon measurements at current and future colliders are outlined.
Comments:
Final version accepted by PRD Letter
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
arXiv:
2107.13007 [pdf]
PRD(2022)·91 citations
08
[Submitted on 27 Jul 2021] (cross-list from hep-ph)
Charm-baryon semileptonic decays and the strange $Λ^{*}$ resonances: New insights from lattice QCD
Stefan Meinel🇺🇸 · Gumaro Rendon🇺🇸
Understanding the properties of the strange $Λ^{*}$ baryon resonances is a long-standing and fascinating problem. $Λ_{c}$ charm-baryon semileptonic weak decays to these resonances are highly sensitive to their internal structure and can be used to test theoretical models. We have performed the first lattice-QCD computation of the form factors governing $Λ_{c}$ semileptonic decays to a $Λ^{*}$ resonance: the $Λ^{*} (1520)$ , which has negative parity and spin $3/2$ . Here we present the resulting Standard-Model predictions of the $Λ_{c} \to Λ^{*} (1520) ℓ^{+} ν_{ℓ}$ differential and integrated decay rates as well as angular observables. Furthermore, by combining the recent BESIII measurement of the $Λ_{c} \to X e^{+} ν_{e}$ inclusive semipositronic branching fraction [Phys. Rev. Lett. 121, 251801 (2018)] with lattice-QCD predictions of the $Λ_{c} \to Λ e^{+} ν_{e}$ , $Λ_{c} \to n e^{+} ν_{e}$ , and $Λ_{c} \to Λ^{*} (1520) e^{+} ν_{e}$ decay rates, we obtain an upper limit on the sum of the branching fractions to all other semipositronic final states. In particular, this upper limit constrains the $Λ_{c} \to Λ^{*} (1405) e^{+} ν_{e}$ branching fraction to be very small, which may be another hint for a molecular structure of the $Λ^{*} (1405)$ .
Comments:
6 pages, 1 figure
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2107.13084 [pdf]
PRD(2022)·20 citations
09
[Submitted on 28 Jul 2021] (cross-list from hep-lat)
$Λ_{c} \to Λ^{*} (1520)$ form factors from lattice QCD and improved analysis of the $Λ_{b} \to Λ^{*} (1520)$ and $Λ_{b} \to Λ_{c}^{*} (2595, 2625)$ form factors
Stefan Meinel🇺🇸 · Gumaro Rendon🇺🇸
We present the first lattice-QCD calculation of the form factors governing the charm-baryon semileptonic decays $Λ_{c} \to Λ^{*} (1520) ℓ^{+} ν_{ℓ}$ . As in our previous calculation of the $Λ_{b} \to Λ^{*} (1520)$ form factors, we work in the $Λ^{*} (1520)$ rest frame, but here we use four different heavy-baryon momenta instead of just two. Because of the lower mass of the $Λ_{c}$ , the moderately-sized momenta used here are sufficient to determine the form factors in the full kinematic range of the semileptonic decay. We also update the analysis of our lattice results for the $Λ_{b} \to Λ^{*} (1520)$ and $Λ_{b} \to Λ_{c}^{*} (2595, 2625)$ form factors by imposing exact relations among the different form factors at zero recoil that follow from rotational symmetry. Imposing these relations ensures the correct behavior of the angular observables near the endpoint.
Comments:
33 pages, 17 figures, 52 form factors
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2107.13140 [pdf]
PRD(2022)·64 citations
10
[Submitted on 28 Jul 2021] (cross-list from hep-ph)
Impact of W and Z Production Data and Compatibility of Neutrino DIS Data in Nuclear Parton Distribution Functions
K. F. Muzakka🇩🇪 · P. Duwentäster🇩🇪 · T. J. Hobbs🇺🇸 · T. Ježo🇩🇪 · M. Klasen🇩🇪 · K. Kovařík🇩🇪 · A. Kusina🇵🇱 · J. G. Morfín🇺🇸 · F. I. Olness🇺🇸 · R. Ruiz🇵🇱 · I. Schienbein🇫🇷 · J. Y. Yu🇫🇷
Vector boson production and neutrino deep-inelastic scattering (DIS) data are crucial for constraining the strange quark parton distribution function (PDF) and more generally for flavor decomposition in PDF extractions. We extend the nCTEQ15 nuclear PDFs (nPDFs) by adding the recent $W$ and $Z$ production data from the LHC in a global nPDF fit. The new nPDF set, referred to as nCTEQ15WZ, is used as a starting point for a follow-up study in which we assess the compatibility of neutrino DIS data with charged lepton DIS data. Specifically, we re-analyze neutrino DIS data from NuTeV, Chorus, and CDHSW, as well as dimuon data from CCFR and NuTeV. To scrutinize the level of compatibility, different kinematic regions of the neutrino data are investigated. Fits to the neutrino data alone and a preliminary global fit are performed and compared to nCTEQ15WZ.
Comments:
8 pages, 4 figures. Submission to SciPost
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2107.13235 [pdf]
SciPost Phys.Proc.(2022)·2 citations
11
[Submitted on 28 Jul 2021] (cross-list from hep-ph)
Reweighting the quark Sivers function with STAR jet data
Carlo Flore🇫🇷 · Maria Elena Boglione🇮🇹 · Umberto D'Alesio🇮🇹 · Josè Osvaldo Gonzalez-Hernandez🇮🇹 · Francesco Murgia🇮🇹 · Alexei Prokudin🇺🇸
The Bayesian reweighting procedure is applied for the first time to a TMD distribution, the quark Sivers function extracted from SIDIS data. By exploiting the recent published single spin asymmetry data for the inclusive jet production in $p^{↑} p$ collisions from the STAR collaboration at RHIC, we show how such a procedure allows to incorporate the information contained in the new data set, without the need of re-fitting, and to explore a much wider $x$ region compared to SIDIS measurements. The reweighting method is also extended to the case of asymmetric errors, and the results show a significant improvement on the knowledge of the quark Sivers function.
Comments:
8 pages, 3 figures. Contribution to the XXVIII International Workshop on Deep-Inelastic Scattering and Related Subjects (DIS2021). Submission to SciPost Proceedings
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
2107.13311 [pdf]
SciPost Phys.Proc.(2022)·1 citation
12
[Submitted on 28 Jul 2021] (cross-list from hep-ph)
NLO inclusive $J / ψ$ photoproduction at large $P_{T}$ at HERA and the EIC
Carlo Flore🇫🇷 · Jean-Philippe Lansberg🇫🇷 · Hua-Sheng Shao🇫🇷 · Yelyzaveta Yedelkina🇫🇷
We study inclusive $J / ψ$ photoproduction at NLO at large $P_{T}$ at HERA and the EIC. Our computation includes NLO QCD leading- $P_{T}$ corrections, QED contributions via an off-shell photon as well as those from $J / ψ$ +charm channels. For the latter, we employ the variable-flavour-number scheme. Our results are found to agree with the latest HERA data by H1 and provide, for the first time, a reliable estimate of the EIC reach for such a measurement. Finally, we demonstrate the observability of $J / ψ$ +charm production and the sensitivy to probe the non-perturbative charm content of the proton at high $x$ , also known as intrinsic charm, at the EIC.
Comments:
7 pages, 3 figures. Contribution to the XXVIII International Workshop on Deep-Inelastic Scattering and Related Subjects (DIS2021). Submission to SciPost Proceedings. Typo corrected
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
2107.13434 [pdf]
SciPost Phys.Proc.(2022)·2 citations

Affiliations

first authorsco-authorsvia INSPIRE