Nuclear Theory·nucl-th

Friday·June 23, 2023

9 papers—4 primary·5 cross-listed

05
[Submitted on 21 Jun 2023] (cross-list from astro-ph.HE)
Impact of Pycnonuclear Fusion Uncertainties on the Cooling of Accreting Neutron Star Crusts
R. Jain · E. F. Brown · H. Schatz · A. V. Afanasjev · M. Beard · L. R. Gasques · S. S. Gupta · G. W. Hitt · W. R. Hix · R. Lau · P. Moller · W. J. Ong · M. Wiescher · Y. Xu
The observation of X-rays during quiescence from transiently accreting neutron stars provides unique clues about the nature of dense matter. This, however, requires extensive modeling of the crusts and matching the results to observations. The pycnonuclear fusion reaction rates implemented in these models are theoretically calculated by extending phenomenological expressions and have large uncertainties spanning many orders of magnitude. We present the first sensitivity studies of these pycnonuclear fusion reactions in realistic network calculations. We also couple the reaction network with the thermal evolution code dStar to further study their impact on the neutron star cooling curves in quiescence. Varying the pycnonuclear fusion reaction rates alters the depth at which nuclear heat is deposited although the total heating remains constant. The enhancement of the pycnonuclear fusion reaction rates leads to an overall shallower deposition of nuclear heat. The impurity factors are also altered depending on the type of ashes deposited on the crust. These total changes correspond to a variation of up to 9 eV in the modeled cooling curves. While this is not sufficient to explain the shallow heat source, it is comparable to the observational uncertainties and can still be important for modeling the neutron star crust.
Comments:
AASTeX63, 11 pages with 9 figures
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Theory (nucl-th)
arXiv:
2306.12451 [pdf]
ApJ(2023)·7 citations
06
[Submitted on 21 Jun 2023] (cross-list from quant-ph)
Two species $k$ -body embedded Gaussian unitary ensembles: $q$ -normal form of the eigenvalue density
Manan Vyas · V. K. B. Kota
Eigenvalue density generated by embedded Gaussian unitary ensemble with $k$ -body interactions for two species (say $π$ and $ν$ ) fermion systems is investigated by deriving formulas for the lowest six moments. Assumed in constructing this ensemble, called EGUE( $k : π ν$ ), is that the $π$ fermions ( $m_{1}$ in number) occupy $N_{1}$ number of degenerate single particle (sp) states and similarly $ν$ fermions ( $m_{2}$ in number) in $N_{2}$ number of degenerate sp states. The Hamiltonian is assumed to be $k$ -body preserving $(m_{1}, m_{2})$ . Formulas with finite $(N_{1}, N_{2})$ corrections and asymptotic limit formulas both show that the eigenvalue density takes $q$ -normal form with the $q$ parameter defined by the fourth moment. The EGUE( $k : π ν$ ) formalism and results are extended to two species boson systems. Results in this work show that the $q$ -normal form of the eigenvalue density established only recently for identical fermion and boson systems extends to two species fermion and boson systems.
Comments:
21 pages, 3 figures, version accepted for publication in J. Stat. Mech. (2023)
Subjects:
Quantum Physics (quant-ph); math.ST (math.ST); nlin.CD (nlin.CD); Nuclear Theory (nucl-th); stat.TH (stat.TH)
arXiv:
2306.12513 [pdf]
J.Stat.Mech.(2023)·1 citation
07
[Submitted on 22 Jun 2023] (cross-list from hep-ph)
Exclusive $J /Ψ$ plus jet associated production in ultraperipheral $P b P b$ collisions
Victor P. Goncalves🇩🇪 · Michael Klasen🇩🇪 · Bruno D. Moreira🇧🇷
The study of exclusive processes in ultraperipheral collisions at the Large Hadron Collider (LHC) has allowed us to test several aspects of the Standard Model and to search for New Physics. In this letter, we investigate the possibility of using these processes to improve our understanding of the quarkonium production mechanism through the study of the exclusive $J /Ψ$ plus jet associate production in ultraperipheral $P b P b$ collisions. We estimate the transverse - momentum and rapidity distributions considering that the $γ γ \to J /Ψ + X$ ( $X = γ, g$ ) subprocess is described by the Non - Relativistic QCD (NRQCD) formalism and present predictions for the rapidity ranges covered by central and forward detectors. The experimental separation of these events is discussed and the results indicate that a future experimental analysis is, in principle, feasible in future runs of the LHC and the Future Circular Collider (FCC).
Comments:
9 pages, 4 figures, 2 tables
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2306.12721 [pdf]
EPJC(2023)·3 citations
08
[Submitted on 22 Jun 2023] (cross-list from hep-ph)
Production of fully-heavy tetraquark states through the double parton scattering mechanism in $pp$ and $p A$ collisions
L. M. Abreu🇧🇷 · F. Carvalho🇧🇷 · J. V. C. Cerqueira🇧🇷 · V. P. Goncalves🇩🇪
The production of fully-heavy tetraquark states in proton-proton ( $pp$ ) and proton-nucleus ( $p A$ ) collisions at the center-of-mass energies of the Large Hadron Collider (LHC) and at the Future Circular Collider (FCC) is investigated considering that these states are produced through the double parton scattering mechanism. We estimate the cross sections for the $T_{4 c}$ , $T_{4 b}$ and $T_{2 b 2 c}$ states and present predictions for $pp$ , $pC a$ and $pP b$ collisions considering the rapidity ranges covered by central and forward detectors. We demonstrate that the cross sections for $p A$ collisions are enhanced in comparison to the $pp$ predictions scaled by the atomic number. Moreover, our results indicate that a search of these exotic states is, in principle, feasible in the future runs of the LHC and FCC.
Comments:
9 pages, 3 figures, 2 tables
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2306.12731 [pdf]
EPJC(2024)·17 citations
09
[Submitted on 22 Jun 2023] (cross-list from hep-ph)
Holographic description of elastic photon-proton and photon-photon scattering
Akira Watanabe🇨🇳 · Zabihullah Ahmadi🇨🇳 · Zhibo Liu🇨🇳 · Wei Xie🇨🇳
We investigate the elastic photon-proton and photon-photon scattering in a holographic QCD model, focusing on the Regge regime. Considering contributions of the Pomeron and Reggeon exchange, the total and differential cross sections are calculated. While our model involves several parameters, by virtue of the universality of the Pomeron and Reggeon, for most of them the values determined in the preceding study on the proton-proton and proton-antiproton scattering can be employed. Once the two adjustable parameters, the Pomeron-photon and Reggeon-photon coupling constant, are determined with the experimental data of the total cross sections, predicting the both cross sections in a wide kinematic region, from the GeV to TeV scale, becomes possible. We show that the total cross section data can be well described within the model, and our predictions for the photon-proton differential cross section are consistent with the data.
Comments:
13 pages, 3 figures, typos corrected. arXiv admin note: text overlap with arXiv:2306.00564
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2306.12890 [pdf]
PLB(2024)·2 citations

Affiliations

first authorsco-authorsvia INSPIRE

Impact of Pycnonuclear Fusion Uncertainties on the Cooling of Accreting Neutron Star Crusts

Two species k-body embedded Gaussian unitary ensembles: q-normal form of the eigenvalue density

Exclusive J/Ψ plus jet associated production in ultraperipheral PbPb collisions

Production of fully-heavy tetraquark states through the double parton scattering mechanism in pp and pA collisions

Holographic description of elastic photon-proton and photon-photon scattering

Affiliations

Two species $k$ -body embedded Gaussian unitary ensembles: $q$ -normal form of the eigenvalue density

Exclusive $J /Ψ$ plus jet associated production in ultraperipheral $P b P b$ collisions

Production of fully-heavy tetraquark states through the double parton scattering mechanism in $pp$ and $p A$ collisions