Nuclear Theory·nucl-th

Tuesday·August 6, 2024

11 papers—6 primary·5 cross-listed

07
Old neutron stars as a new probe of relic neutrinos and sterile neutrino dark matter
Saurav Das🇺🇸 · P. S. Bhupal Dev🇺🇸 · Takuya Okawa🇺🇸 · Amarjit Soni🇺🇸
We study the kinetic cooling (heating) of old neutron stars due to coherent scattering with relic neutrinos (sterile neutrino dark matter) via Standard Model neutral-current interactions. We take into account several important physical effects, such as gravitational clustering, coherent enhancement, neutron degeneracy and Pauli blocking. We find that the anomalous cooling of nearby neutron stars due to relic neutrino scattering might actually be observable by current and future telescopes operating in the optical to near-infrared frequency band, such as the James Webb Space Telescope (JWST), provided there is a large local relic overdensity that is still allowed. Similarly, the anomalous heating of neutron stars due to coherent scattering with keV-scale sterile neutrino dark matter, could also be observed by JWST or future telescopes, which would probe hitherto unexplored parameter space in the sterile neutrino mass-mixing plane.
↳ hep-phastro-ph.HEastro-ph.SRnucl-thPRD(2025)·15 citations
08
Linearized fluctuating hydrodynamics via random polynomials
Farid Taghinavaz🇮🇷 · Giorgio Torrieri🇧🇷
We argue that an ensemble of backgrounds best understands hydrodynamic dispersion relations in a medium with few degrees of freedom and is therefore subject to strong thermal fluctuations. In the linearized regime, dispersion relations become describeable by polynomials with random coefficients. We give a short review of this theory and perform a numerical study of the distribution of the roots of polynomials whose coefficients are of the order of a Knudsen series but fluctuate in accordance with canonical fluctuations of temperature. We find that, remarkably, the analytic structure of the poles of fluctuating dispersion relations is very different from deterministic ones, particularly regarding the distribution of imaginary parts with respect to real components. We argue that this provides evidence that hydrodynamic behavior persists, and is enhanced, by non-perturbative background fluctuations.
↳ hep-thhep-phnucl-thPRD(2024)·3 citations
09
Calculation of Some Integrals over Gaussian Measure with Nuclear Covariance Operator in Separable Hilbert Space
Nikita A. Ignatyuk🇷🇺 · Anna A. Ogarkova🇷🇺 · Stanislav L. Ogarkov🇷🇺
The main purpose of this paper is to construct convergent series for the approximate calculation of certain integrals over the Gaussian measure with a nuclear covariance operator, nonlocal propagator, in separable Hilbert space. Such series arise, for example, in the model with the interaction Lagrangian $sinh^{2 (p + 1)} φ$ , where $p \in N$ and $φ$ is the scalar field, although the problem can be solved in general form for a fairly wide class of Lagrangians: an even, strictly convex, continuous, non-negative function with a single zero value for $φ = 0$ and for $∣ φ ∣ \to + \infty$ growing faster than $φ^{2}$ . We strictly define the scattering matrix, $S$ -matrix, at the zero value of the classical field, argument of the $S$ -matrix, of such a theory in terms of the corresponding integral, find the iterated expansion for the integrand (the Gaussian measure doesn't expand) over two orthonormal bases of functions, prove the validity of summation and integration interchange and thus find the expansion of the $S$ -matrix at the zero value of the classical field into the iterated series in powers of the interaction action. The individual terms of the resulting series have the form of a canonical partition function (CPF), and the methods of statistical physics are applicable to them. In particular, we express them in terms of Bell polynomials. It is important to note that such iterated series cannot be reduced to the perturbation theory (PT) series, since in the proposed model the latter diverges as $e^{n^{2}}$ , where $n \in N$ is the PT order. Along the way, we provide detailed mathematical background, including Beppo Levi's monotone convergence theorem (MCT) and Henri Lebesgue's dominated convergence theorem (DCT), without which the presented calculation would be significantly more complex.
↳ hep-thcond-mat.stat-mechmath-phmath.MP+10 citations
10
A possible evidence of pion condensation
Wei Zhu🇨🇳 · Yu-Chen Tang🇨🇳 · Lei Feng🇨🇳 · Feng-yao Hou🇨🇳
This work demonstrates that once a large number of pion is condensed in a high-energy hadron collision, the gamma-ray spectrum from $π^{0}$ decay takes on a typical broken power-law shape, which has been documented in many astronomical observations, but we have not yet recognized it. We show that this pion condensation is caused by a large number of soft gluons condensed in protons.
↳ hep-phastro-ph.HEcond-mat.othernucl-thCommun.Theor.Phys.(2025)·0 citations
11
The Fate of Weakly Bound Light Nuclei in Central Collider Experiments: a Challenge in Favor of a Late Continuous Decoupling Mechanism
Jörn Knoll🇩🇪
Arguments are presented that the reaction products of central high energy nuclear collisions up to collider energies can rigorously be interpreted in terms of a continuous decoupling mechanism based on continuous equations of motion. The various aspects of the collision dynamics are investigate in terms of the individual decoupling processes. Thereby each observed particle decouples during its own temporal decoupling window. This includes a ``very late'' decoupling of the faintly bound Hypertritons observed in recent ALICE experiments. The success of the strategy is based upon 200 years old wisdom and leads to a revised interpretation of the entire decoupling process.
↳ hep-phnucl-thPLB(2024)·2 citations

Affiliations

first authorsco-authorsvia INSPIRE

Old neutron stars as a new probe of relic neutrinos and sterile neutrino dark matter

Linearized fluctuating hydrodynamics via random polynomials

Calculation of Some Integrals over Gaussian Measure with Nuclear Covariance Operator in Separable Hilbert Space

A possible evidence of pion condensation

The Fate of Weakly Bound Light Nuclei in Central Collider Experiments: a Challenge in Favor of a Late Continuous Decoupling Mechanism

Affiliations