Nuclear Theory·nucl-th

Monday·August 21, 2023

17 papers—8 primary·9 cross-listed

09
[Submitted on 16 Aug 2023] (cross-list from hep-th)
Finite System Size Correction to the Effective Coupling in $ϕ^{4}$ Scattering
W. A. Horowitz🇿🇦 · J. F. Du Plessis🇿🇦
We compute and explore numerically the finite system size correction to NLO $2 \to 2$ scattering in massive scalar $ϕ^{4}$ theory. The derivation uses "denominator regularization" (instead of the usual dimensional regularization) on a spacetime with spatial directions compactified to a torus, with characteristic lengths not necessarily of equal size. We determine a useful analytic continuation of the generalized Epstein zeta function to isolate the usual UV divergence. Self-consistently, the renormalized finite system size correction reduces to zero as the system size goes to infinity and, further, satisfies the optical theorem. One of our checks of unitarity leads to a generalization of a number theoretic result from Hardy and Ramanujan. Precise numerical exploration of the finite system size correction to the amplitude and coupling when two spatial dimensions are finite requires the exploitation of the analytic structure of the finite system size result via a dispersion relation. We find that the finite system size scattering amplitude exhibits "geometric" bound states. Even away from these bound states, the finite system size correction to the effective coupling can be large.
Comments:
34 pages, 24 figures
Subjects:
High Energy Physics — Theory (hep-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2308.08651 [pdf]
PRD(2024)·1 citation
10
[Submitted on 17 Aug 2023] (cross-list from hep-ph)
Compositeness of near-threshold exotic hadrons with decay and coupled-channel effects
Tomona Kinugawa🇯🇵 · Tetsuo Hyodo🇯🇵
The near-threshold exotic hadrons such as $T_{cc}$ and $X (3872)$ are naively considered as the hadronic molecular state from the viewpoint of the low-energy universality. However, it is also known that the elementary dominant state is not completely excluded as the internal structure of the near-threshold states. Furthermore, the dominance of molecules is expected to be modified by the decay or coupled channels. We discuss these features of the near-threshold bound states by calculating the compositeness with the effective field theory.
Comments:
4 pages, 2 figures, Proceedings of 17th International Workshop on Meson Physics (MESON2023), 22nd - 27th June, 2023
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2308.08801 [pdf]
EPJ Web Conf.(2024)·0 citations
11
[Submitted on 17 Aug 2023] (cross-list from hep-ph)
Associated vector meson and bound-free electron-positron pair photoproduction in ultraperipheral $P b P b$ collisions
Celsina N. Azevedo🇧🇷 · Victor P. Goncalves🇧🇷 · Bruno D. Moreira🇧🇷
In this letter we analyze the associated production of a vector meson with the bound - free $e^{+} e^{-}$ process in ultraperipheral $P b P b$ collisions through the double scattering mechanism for the energy of the Large Hadron Collider (LHC). Such process is characterized by the presence of a meson and a positron in the final state and by a forward hydrogen - like ion with a distinct electric charge. We present our predictions for the total cross sections and rapidity distributions considering the rapidity ranges covered by the ALICE and LHCb detectors, which indicate that a future experimental analysis of the $ϕ + e^{+}$ and $J /Ψ + e^{+}$ final states is feasible.
Comments:
5 pages, 2 figures, 1 table. arXiv admin note: substantial text overlap with arXiv:2306.05519
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2308.09120 [pdf]
PRC(2023)·2 citations
12
[Submitted on 17 Aug 2023] (cross-list from hep-ph)
Deep Exclusive Meson Production as a probe to the puzzle of $Λ$ hyperon polarization
Zhoudunming Tu🇺🇸
In the 1970s, an unexpected transverse $Λ$ polarization in unpolarized proton-Beryllium collisions was discovered, which initiated extensive studies on spin phenomena in high-energy physics. Over the past five decades, similar transverse $Λ$ polarization has been observed across various collision systems, including lepton-hadron deep inelastic scattering, hadron-hadron collisions, and electron-positron collisions. Despite numerous promising theoretical models, the fundamental mechanism underlying this polarization phenomenon remains inconclusive to this day. However, in both longitudinally and transversely polarized lepton-hadron and hadron-hadron collisions, it is found that the $Λ$ hyperon is not polarized with respect to the initial parton spin direction. How the $Λ$ hyperon acquires its spin has become one of the most crucial questions to address in order to resolve this puzzle. In this paper, I propose to use an exclusive process that can be measured at the Electron-Ion Collider, the Deep Exclusive Meson Production, to explicitly test the mechanism of $Λ$ polarization. The outcomes of this experimental measurement are anticipated to unveil the dominant mechanism by which $Λ$ obtains its spin, eliminating many of the ambiguities that have been encountered in previous studies. Finally, experimental challenges and requirements will be discussed.
Comments:
Final version published in journal
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2308.09127 [pdf]
PRC(2024)·11 citations
13
[Submitted on 18 Aug 2023] (cross-list from astro-ph.HE)
Atmospheric Effects on Neutron Star Parameter Constraints with NICER
Tuomo Salmi🇳🇱 · Serena Vinciguerra🇳🇱 · Devarshi Choudhury🇳🇱 · Anna L. Watts🇳🇱 · Wynn C. G. Ho🇺🇸 · Sebastien Guillot🇫🇷 · Yves Kini🇳🇱 · Bas Dorsman🇳🇱 · Sharon M. Morsink🇨🇦 · Slavko Bogdanov🇺🇸
We present an analysis of the effects of uncertainties in the atmosphere models on the radius, mass, and other neutron star parameter constraints for the NICER observations of rotation-powered millisecond pulsars. To date, NICER has applied the X-ray pulse profile modeling technique to two millisecond-period pulsars: PSR J0030+0451 and the high-mass pulsar PSR J0740+6620. These studies have commonly assumed a deep-heated, fully ionized hydrogen atmosphere model, although they have explored the effects of partial-ionization and helium composition in some cases. Here, we extend that exploration and also include new models with partially ionized carbon composition, externally heated hydrogen, and an empirical atmospheric beaming parameterization to explore deviations in the expected anisotropy of the emitted radiation. None of the studied atmosphere cases have any significant influence on the inferred radius of PSR J0740+6620, possibly due to its X-ray faintness, tighter external constraints, and/or viewing geometry. In the case of PSR J0030+0451, both the composition and ionization state could significantly alter the inferred radius. However, based on the evidence (prior predictive probability of the data), partially ionized hydrogen and carbon atmospheres are disfavored. The difference in the evidence for ionized hydrogen and helium atmospheres is too small to be decisive for most cases, but the inferred radius for helium models trends to larger sizes around or above 14-15 km. External heating or deviations in the beaming that are less than $5 %$ at emission angles smaller than 60 degrees, on the other hand, have no significant effect on the inferred radius.
Comments:
26 pages, 12 figures (2 of which are figure sets), 3 tables. Published in ApJ
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Theory (nucl-th)
arXiv:
2308.09319 [pdf]
ApJ(2023)·41 citations
14
[Submitted on 18 Aug 2023] (cross-list from hep-ph)
Proton number cumulants in a modified van der Waals hadron resonance gas
Kshitish Kumar Pradhan🇮🇳 · Ronald Scaria🇮🇳 · Dushmanta Sahu🇮🇳 · Raghunath Sahoo🇮🇳
An estimate of the proton number cumulants in the hadronic matter is presented considering a van der Waals-type interaction between the constituent particles. We argue that the attractive and repulsive parameters in the VDW hadron resonance gas (VDWHRG) model change as functions of baryochemical potential ( $μ_{B}$ ) and temperature ( $T$ ). This, in turn, affects the estimation of thermodynamic properties and, consequently, the conserved charge fluctuations. We employ a simple parametrization to bring in the center-of-mass energy ( $s_{NN}$ ) dependence on temperature and baryochemical potential and then estimate the proton number cumulants with the modified approach. The modified van der Waals hadron resonance gas model (MVDWHRG) explains the existing experimental data very well.
Comments:
9-pages and 6-captioned figures, Submitted for publication
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2308.09337 [pdf]
5 citations
15
[Submitted on 18 Aug 2023] (cross-list from hep-ph)
$K^{+} N$ elastic scatterings for estimation of in-medium quark condensate with strange quarks
Yutaro Iizawa🇯🇵 · Daisuke Jido🇯🇵 · Stephan Hübsch🇯🇵
We revisit the low-energy $K^{+} N$ elastic scatterings in the context of the in-medium quark condensate with strange quarks. The chiral ward identity connects the in-medium quark condensate to the soft limit value of the pseudoscalar correlation function evaluated in nuclear matter. The in-medium correlation function of the psuedoscalar fields with strangeness describes in-medium kaon propagation and is obtained by kaon-nucleon scattering amplitudes in the low density approximation. We construct the kaon-nucleon scattering amplitudes in chiral perturbation theory up to the next-to-leading order and add some terms of the next-to-next-to-leading order with the strange quark mass to improve expansion of the strange quark sector. We also consider the effect of a possible broad resonance state around $P_{lab} = 600$ MeV/c for $I = 0$ reported in the previous study. The low energy constants are determined by existent $K^{+} N$ scattering data. We obtain good reproduction of the $K^{+} p$ scattering amplitude by chiral perturbation theory, while the description of the $K N$ amplitude with $I = 0$ is not so satisfactory due to the lack of low energy data. Performing analytic continuation of the scattering amplitudes obtained by chiral perturbation theory to the soft limit, we estimate the in-medium strange quark condensate.
Comments:
34 pages, 11 figures, 5 tables
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2308.09397 [pdf]
PTEP(2024)·5 citations
16
[Submitted on 18 Aug 2023] (cross-list from astro-ph.HE)
An updated mass-radius analysis of the 2017-2018 NICER data set of PSR J0030+0451
Serena Vinciguerra · Tuomo Salmi · Anna L. Watts · Devarshi Choudhury · Thomas E. Riley · Paul S. Ray · Slavko Bogdanov · Yves Kini · Sebastien Guillot · Deepto Chakrabarty · Wynn C. G. Ho · Daniela Huppenkothen · Sharon M. Morsink · Zorawar Wadiasingh
In 2019 the NICER collaboration published the first mass and radius inferred for PSR J0030+0451, thanks to NICER observations, and consequent constraints on the equation of state characterising dense matter. Two independent analyses found a mass of $\sim 1.3 - 1.4 M_{⊙}$ and a radius of $\sim 13$ km. They also both found that the hot spots were all located on the same hemisphere, opposite to the observer, and that at least one of them had a significantly elongated shape. Here we reanalyse, in greater detail, the same NICER data set, incorporating the effects of an updated NICER response matrix and using an upgraded analysis framework. We expand the adopted models and jointly analyse also XMM-Newton data, which enables us to better constrain the fraction of observed counts coming from PSR J0030+0451. Adopting the same models used in previous publications, we find consistent results, although with more stringent inference requirements. We also find a multi-modal structure in the posterior surface. This becomes crucial when XMM-Newton data is accounted for. Including the corresponding constraints disfavors the main solutions found previously, in favor of the new and more complex models. These have inferred masses and radii of $\sim [1.4 M_{⊙}, 11.5$ km] and $\sim [1.7 M_{⊙}, 14.5$ km], depending on the assumed model. They display configurations that do not require the two hot spots generating the observed X-rays to be on the same hemisphere, nor to show very elongated features, and point instead to the presence of temperature gradients and the need to account for them.
Comments:
35 pages, 11 figures, 7 tables
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Theory (nucl-th)
arXiv:
2308.09469 [pdf]
ApJ(2024)·276 citations
17
[Submitted on 18 Aug 2023] (cross-list from cond-mat.quant-gas)
Emergent interaction-driven elliptic flow of few fermionic atoms
Sandra Brandstetter🇩🇪 · Philipp Lunt🇩🇪 · Carl Heintze🇩🇪 · Giuliano Giacalone🇩🇪 · Lars H. Heyen🇩🇪 · Maciej Gałka🇩🇪 · Keerthan Subramanian🇩🇪 · Marvin Holten🇩🇪 · Philipp M. Preiss🇩🇪 · Stefan Floerchinger🇩🇪 · Selim Jochim🇩🇪
Hydrodynamics provides a successful framework to effectively describe the dynamics of complex many-body systems ranging from subnuclear to cosmological scales by introducing macroscopic quantities such as particle densities and fluid velocities. According to textbook knowledge, it requires coarse graining over microscopic constituents to define a macroscopic fluid cell, which is large compared to the interparticle spacing and the mean free path. In addition, the entire system must consist of many such fluid cells. In high energy heavy ion collisions, hydrodynamic behaviour is inferred from the observation of elliptic flow. Here, we demonstrate the emergence of elliptic flow in a system of few strongly interacting atoms. In our system a hydrodynamic description is a priori not applicable, as all relevant length scales, i.e. the system size, the inter-particle spacing, and the mean free path are comparable. The single particle resolution, deterministic control over particle number and interaction strength in our experiment allow us to explore the boundaries between a microscopic description and a hydrodynamic framework in unprecedented detail.
Comments:
11 pages, 6 figures
Subjects:
Quantum Gases (cond-mat.quant-gas); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
arXiv:
2308.09699 [pdf]
Nat.Phys.(2025)·36 citations

Affiliations

first authorsco-authorsvia INSPIRE