Mass Scale Research Articles

Deformation-induced CPT violation in entangled pairs of neutral kaons

In this paper we consider description of kaon-antikaon interference in the context of a theory with deformed CPT symmetry. In the case of such theoretical models, deviations from the standard CPT invariance is related to the momentum carried by the particles; in particular the rest masses of particles and antiparticles are equal. We find that the decay intensity of kaon-antikaon pair has three contributing terms: the correct-parity, the wrong-parity, and the interference between them, all of which are affected by deformation. Using the fact that the presence of such terms was not observed we estimate, under plausible assumptions, the magnitude of deformation parameter κ≳1017 GeV at the LHC energy. This limit can be possibly improved to values closer to the expected Planck mass scale κ≳1018 GeV using a next-generation collider with energy larger by an order of magnitude. This raises hopes that the effect, if it exists, could be detected in future accelerator experiments. Uncertainties of the energy measurement and time resolution are important for accuracy of these predictions. Published by the American Physical Society 2024

The baryon cycle in modern cosmological hydrodynamical simulations

ABSTRACT In recent years, cosmological hydrodynamical simulations have proven their utility as key interpretative tools in the study of galaxy formation and evolution. In this work, we present a comparative analysis of the baryon cycle in three publicly available, leading cosmological simulation suites: EAGLE, IllustrisTNG, and SIMBA. While these simulations broadly agree in terms of their predictions for the stellar mass content and star formation rates of galaxies at $z\approx 0$, they achieve this result for markedly different reasons. In EAGLE and SIMBA, we demonstrate that at low halo masses ($M_{\rm 200c}\lesssim 10^{11.5}\, \mathrm{M}_{\odot }$), stellar feedback (SF)-driven outflows can reach far beyond the scale of the halo, extending up to $2\!-\!3\times R_{\rm 200c}$. In contrast, in TNG, SF-driven outflows, while stronger at the scale of the interstellar medium, recycle within the circumgalactic medium (within $R_{\rm 200c}$). We find that active galactic nucleus (AGN)-driven outflows in SIMBA are notably potent, reaching several times $R_{\rm 200c}$ even at halo masses up to $M_{\rm 200c}\approx 10^{13.5}\, \mathrm{M}_{\odot }$. In both TNG and EAGLE, AGN feedback can eject gas beyond $R_{\rm 200c}$ at this mass scale, but seldom beyond $2\!-\!3\times R_{\rm 200c}$. We find that the scale of feedback-driven outflows can be directly linked with the prevention of cosmological inflow, as well as the total baryon fraction of haloes within $R_{\rm 200c}$. This work lays the foundation to develop targeted observational tests that can discriminate between feedback scenarios, and inform subgrid feedback models in the next generation of simulations.

Optimizing Goldfish (Carassius auratus) Breeding and Larval Nurturing for Materialistic Aquaculture Utilizing Synthetic Hormones

Gold fish (Carassius auratus) are familiar in India as an ornamental freshwater fish with economic importance. This experiment aimed to explore the possibility for mass-scale breeding and larval rearing of goldfish under biofloc setup. Natural brooders were collected, acclimatized and induced to breed utilizing synthetic hormones at various dosages. Breeding execution parameters namely spawning success, fertilization rate and hatching performance were analysed. The highest fertilization and hatching rate were gradually noticed at 80.8% and 80.9% by using a dose of 0.4ml/kg body weight for females and 0.2ml/kg for males. Larval rearing was accomplish by applying several live and formulated feeds across various life stages in normal rearing tanks and biofloc tanks also. The growth performance of larvae in biofloc tanks express a satisfactory rate, with a maximum weight gain of 7.1 g and length gain of 5 cm over 120 days compared to 5.1 g and 3.5 cm in normal tanks. Water quality parameters were kept within the optimum range all over the experiment. The functionable study exhibits the viability of captive breeding and mass scale larval nurturing of goldfish employing induced breeding techniques and biofloc technology.

Dark matter production accompanied by gravitational wave signals during cosmological phase transitions

We investigate the temperature-dependent production of feebly interacting massive dark matter particle (FIMP DM) within a Z2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$Z_2$$\\end{document} model, incorporating two Z2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$Z_2$$\\end{document}-odd scalar fields. In specific parameter regions, three distinct mechanisms individually dominate the production of the FIMP DM. These mechanisms include the semi-production process, commonly known as the “exponential growth” process, the three-body decay process, and the production from pair annihilations of the bath particles. It is crucial to consider the thermal history during the evolution of FIMPs, as it involves multiple phase transitions occurring prior to the freeze-in of dark matter. Consequently, the scalar masses experience thermal variations, leading to distinctive evolutionary trajectories for FIMPs when compared to scenarios without accounting for the thermal effects. Notably, the unique patterns of FIMP evolution are accompanied by the production of gravitational waves, presenting promising opportunities for detection using forthcoming interferometers.

Hadronic spectrum in the chiral large Nc extension of quantum chromodynamics

We study quantum chromodynamics in the chiral large Nc limit which contains a left-handed Weyl fermion in the fundamental representation, a left-handed Weyl fermion in the two index antisymmetric representation and (Nc−3) left-handed Weyl fermions in the antifundamental representation of the SU(Nc) gauge group. We construct gauge singlet composite operators and study their masses and correlation functions at large Nc. It is shown that all hadron masses scale as ∼Nc0nq where nq is the number of constituent quarks in the hadron. In addition by simple gluon exchange considerations it is seen that scattering amplitudes between hadrons have the same Nc scaling as the mass of the lightest hadron involved. This is the case provided the hadrons in the scattering amplitude share a sufficiently large number of constituent quarks. The chiral large Nc extension also allows for other nontrivial processes. For instance we consider two different baryonium states that are unique to this extension and that decay via emissions of two- and three-quark hadrons. Also other nontrivial scattering processes are considered. Finally, we study composites made of a mix of left- and right-handed fields. We categorize multiple groups of hadrons within the full spectrum according to their flavor structure. Within these groups all n-point functions scale the same. Published by the American Physical Society 2024

THE SCALE SIMULATION APPLICATION IN THE MILITARY VEHICLES ARMORING

The armoring of the civilian vehicles during martial law requires the search for new parameters selecting methods that provide the required indicators of dynamic properties. The additional armored sheets installation on ordinary civilian vehicles leads to the weight increase, the center of mass position change and dynamic properties deterioration. Therefore, the ordinary civilian vehicles armoring can also be considered from the perspective of large-scale modeling. One of the ways to ensure the necessary dynamic indicators of the ordinary civilian vehicles when armoring is to use the theory of large-scale modeling due to the use of the mass scale as the main scale. In the study, using the theory of similarity, a system of scale coefficients was developed for choosing the main design parameters of armored vehicles. The dependences of engine power, wheel diameter and rigid suspension and tires, engine and transmission torques on the car reservation coefficient are obtained. The value of the indicator of the relevant parameters of the vehicle degree is given. The higher the degree indicator, the higher the sensitivity of the vehicle parameter to increase when armoring. It was determined that different physical (mechanical) quantities have different sensitivity to the increase in the weight of the vehicle. The greatest sensitivity is the value of the engine torque, and the least is the linear dimension. These dependencies can be used in the process of designing a car armoring. In addition, it was determined that there is a relationship between the maximum permissible parameter measurement error during dynamic tests of full-scale models and the maximum permissible parameter measurement error during full-scale machine testing. Іmproved requirements for the dynamic parameters measurement accuracy during armored vehicles tests are considered. During armored vehicles tests, the maximum permissible error of dynamic parameters measuring increases, which makes it possible not to use more complex measuring and recording equipment.

Complete analysis of the Landau-gauge three-gluon vertex from lattice QCD

Several continuum and lattice investigations of the QCD three-gluon vertex have recently exposed its key properties, some intimately connected with the low-momentum behavior of the two-point gluon Green’s function and especially relevant for the emergence of a mass scale in this latter, via the Schwinger mechanism. In the present study, we report on a lattice determination of the Landau-gauge, transversely projected three-gluon vertex, particularly scrutinizing an outstanding one of these properties, termed , exploring its implications and capitalizing on it to gain further insight on the low-momentum running of both the three-gluon vertex and its associated strong coupling. Published by the American Physical Society 2024

“Diminishing returns” in the scaling of leaf area vs. dry mass across 94 teas in China

ABSTRACT The scaling relationship between leaf area and dry mass is commonly employed to balance leaf acquisition and investment strategies. However, the understanding of the scaling of the leaf area and the dry mass in artificially domesticated species is limited, especially in tea. We analyzed the relationships between leaf area and dry mass in 94 tea cultivars across China. Then, we compared the scaling exponent with bamboo (50 species) and trees (252 species) growing under natural conditions. Our results revealed that the leaf area of tea scaled approximately as the 0.76-power with leaf dry mass, which is significantly lower than bamboo (0.86) and trees (1.03). Consequently, it was posited that the growth of the tea leaves may prefer to get more leaf dry mass rather than the expansion of the leaf area due to the long-term influence of artificial domestication.

Emergence of R4-terms in M-theory

It has been recently suggested that the strong Emergence Proposal is realized in M-theory limits by integrating out all light towers of states with a typical mass scale not larger than the species scale, i.e. the eleventh dimensional Planck mass. Within the BPS sector, these are transverse M2- and M5-branes, that can be wrapped and particle-like, carrying Kaluza-Klein momentum along the compact directions. We provide additional evidence for this picture by revisiting and investigating further the computation of R4-interactions in M-theory à la Green-Gutperle-Vanhove. A central aspect is a novel UV-regularization of Schwinger-like integrals, whose actual meaning and power we clarify by first applying it to string perturbation theory. We consider then toroidal compactifications of M-theory and provide evidence that integrating out all light towers of states via Schwinger-like integrals thus regularized yields the complete result for R4-interactions. In particular, this includes terms that are tree-level, one-loop and space-time instanton corrections from the weakly coupled point of view. Finally, we comment on the conceptual difference of our approach to earlier closely related work by Kiritsis-Pioline and Obers-Pioline, leading to a correspondence between two types of constrained Eisenstein series.

Black hole outflows initiated by a large-scale magnetic field

Context. Accreting black hole sources show variable outflows at different mass scales. For instance, in the case of galactic nuclei, our own Galactic center Sgr A* exhibits flares and outbursts in the X-ray and infrared bands. Recent studies suggest that the inner magnetospheres of these sources have a pronounced effect on these emissions. Aims. Accreting plasma carries the frozen-in magnetic flux along with it down to the black hole horizon. During the infall, the magnetic field intensifies, and this can lead to a magnetically arrested state. We investigate the competing effects of inflows at the black hole horizon and the outflows that develop in the accreting plasma through the action of the magnetic field in the inner magnetosphere, and we determine the implications of these effects. Methods. We started with a spherically symmetric Bondi-type inflow and introduced a magnetic field. In order to understand the influence of the initial configuration, we started the computations with an aligned magnetic field with respect to the rotation axis of the black hole. Then we proceeded to the case of magnetic fields that are inclined to the rotation axis of the black hole. We employed the 2D and 3D versions of the code HARM for the aligned field models and used the 3D version for the inclined field. We compared the results of computations with each other. Results. We observe that the magnetic lines of force start to accrete with the plasma while an equatorial intermittent outflow develops. This outflow continues to push some material away from the black hole in the equatorial plane, while some other material is ejected in the vertical direction from the plane. In consequence, the accretion rate fluctuates as well. The direction of the black hole spin prevails at later stages. It determines the flow geometry near the event horizon. On larger scales, however, the flow geometry remains influenced by the initial inclination of the field.

A New Timescale–Mass Scaling for the Optical Variation of Active Galactic Nuclei across the Intermediate-mass to Supermassive Scales

The variability of active galactic nuclei (AGNs) has long been servicing as an essential avenue of exploring the accretion physics of a black hole (BH). There are two commonly used methods for analyzing AGN variability. First, the AGN variability, characterized by the structure function (SF) of a single band, can be well described by a damped random walk (DRW) process on timescales longer than ∼weeks, shorter than which departures have been reported. Second, the color variation (CV) between two bands behaves timescale dependent, raising challenges to the widely accepted reprocessing scenario. However, both the departure from the DRW process and the timescale-dependent CV are hitherto limited to AGNs, mainly quasars, at the supermassive scale. Here, utilizing the high-cadence multiwavelength monitoring on NGC 4395 harboring an intermediate-mass BH, we unveil at the intermediate-mass scale for the first time, prominent departures from the DRW process at timescales shorter than ∼hours in all three nights and bands, and plausible timescale-dependent CVs in the two longest nights of observation. Furthermore, comparing SFs of NGC 4395 to four AGNs at the supermassive scale, we suggest a new scaling relation between the timescale (τ; across nearly 3 orders of magnitude) and the BH mass (M BH): τ∝MBHγ where the exponent γ is likely ≃0.6–0.8. This exponent differs from most previous measurements, but confirms a few, and is consistent with a recent theoretical prediction, suggesting a similar accretion process in AGNs across different mass scales.

Development of generic no-scale inflation

We develop generalized no-scale supergravity models of inflation, and then study the corresponding cosmological predictions as well as the formation of primordial black holes (PBHs) and scalar-induced gravitational waves (SIGWs). With a new parameter 0 < a ≤ 1, the generalized no-scale supergravity provides the continuous connections among the generic no-scale supergravity from string theory compactifications. The resulting prediction of the CMB, spectrum index ns , and tensor-to-scalar ratio r can be highly consistent with the latest Planck/BICEP/Keck Array observations. Notably, the models with a ≠ 1 give a smaller ratio r ≤ 10-3, which is flexible even under the anticipated tighter observational constraints at the future experiments. Additionally, these models have the potential to generate a broad-band stochastic gravitational wave background, and thus explain the NANOGrav 15yr signal. Furthermore, they predict the formation of PBHs with various mass scales, which could account for a significant portion of dark matter relic density in the Universe.

Simulating nearby disc galaxies on the main star formation sequence

Past studies have long emphasised the key role played by galactic stellar bars in the context of disc secular evolution, via the redistribution of gas and stars, the triggering of star formation, and the formation of prominent structures such as rings and central mass concentrations. However, the exact physical processes acting on those structures, as well as the timescales associated with the building and consumption of central gas reservoirs are still not well understood. We are building a suite of hydro-dynamical RAMSES simulations of isolated, low-redshift galaxies that mimic the properties of the PHANGS sample. The initial conditions of the models reproduce the observed stellar mass, disc scale length, or gas fraction, and this paper presents a first subset of these models. Most of our simulated galaxies develop a prominent bar structure, which itself triggers central gas fuelling and the building of an over-density with a typical scale of 100−1000 pc. We confirm that if the host galaxy features an ellipsoidal component, the formation of the bar and gas fuelling are delayed. We show that most of our simulations follow a common time evolution, when accounting for mass scaling and the bar formation time. In our simulations, the stellar mass of 1010 M⊙ seems to mark a change in the phases describing the time evolution of the bar and its impact on the interstellar medium. In massive discs (M⋆ ≥ 1010 M⊙), we observe the formation of a central gas reservoir with star formation mostly occurring within a restricted starburst region, leading to a gas depletion phase. Lower-mass systems (M⋆ &lt; 1010 M⊙) do not exhibit such a depletion phase, and show a more homogeneous spread of star-forming regions along the bar structure, and do not appear to host inner bar-driven discs or rings. Our results seem to be supported by observations, and we briefly discuss how this new suite of simulations can help our understanding of the secular evolution of main sequence disc galaxies.

The Evolution of Galaxies and Clusters at High Spatial Resolution with Advanced X-ray Imaging Satellite (AXIS)

Stellar and black hole feedback heat and disperse surrounding cold gas clouds, launching gas flows off circumnuclear and galactic disks, producing a dynamic interstellar medium. On large scales bordering the cosmic web, feedback drives enriched gas out of galaxies and groups, seeding the intergalactic medium with heavy elements. In this way, feedback shapes galaxy evolution by shutting down star formation and ultimately curtailing the growth of structure after the peak at redshift 2–3. To understand the complex interplay between gravity and feedback, we must resolve both the key physics within galaxies and map the impact of these processes over large scales, out into the cosmic web. The Advanced X-ray Imaging Satellite (AXIS) is a proposed X-ray probe mission for the 2030s with arcsecond spatial resolution, large effective area, and low background. AXIS will untangle the interactions of winds, radiation, jets, and supernovae with the surrounding interstellar medium across the wide range of mass scales and large volumes driving galaxy evolution and trace the establishment of feedback back to the main event at cosmic noon. This white paper is part of a series commissioned for the AXIS Probe mission concept; additional AXIS white papers can be found at the AXIS website.

Experimental neutrino physics in a nuclear landscape.

There are profound connections between neutrino physics and nuclear experiments. Exceptionally precise measurements of single and double beta-decay spectra illuminate the scale and nature of neutrino mass and may finally answer the question of whether neutrinos are their own anti-matter counterparts. Neutrino-nucleus scattering underpins oscillation experiments and probes nuclear structure, neutrinos offer a rare vantage point into collapsing stars and nuclear fission reactors and techniques pioneered in neutrino nuclear physics experiments are advancing quantum sensing technologies. In this article, we review current and planned efforts at the intersection of neutrino and nuclear experiments. This article is part of the theme issue 'The liminal position of Nuclear Physics: from hadrons to neutron stars'.

Vector dark matter with Higgs portal in type II seesaw framework

We study the phenomenology of a vector dark matter (VDM) in a U(1)X gauged extension of the Standard Model (SM), which is set in a type II seesaw framework. When this U(1)X symmetry is spontaneously broken by the vacuum expectation value (VEV) of a newly introduced complex scalar singlet, the gauge boson Z′ becomes massive. The stability of the dark matter (DM) is ensured by the presence of an exact charge conjugation symmetry resulting from the structure of the Lagrangian. On the other hand, the SU(2)L triplet scalar facilitates light neutrino masses via the type II seesaw mechanism. We have studied the phenomenology of the usual WIMP DM, considering all possible theoretical and experimental constraints that are applicable. Due to the presence of a triplet scalar, the present framework can also accommodate the observed 2σ deviation in h→Zγ decay rate, recently measured at the LHC. The possibility of nonthermal production of DM from the decay of the singlet scalar has also been briefly discussed. Published by the American Physical Society 2024

Probing lepton number violation and Majorana nature of neutrinos at the LHC

Observation of lepton number (L) violation by two units at colliders would provide evidence for the Majorana nature of neutrinos. We study signals of L-violation in the context of two popular models of neutrino masses, the type-II seesaw model and the Zee model, wherein small neutrino masses arise at the tree-level and one-loop level, respectively. We focus on L-violation signals at the LHC arising through the process pp → ℓ±ℓ′± + jets within these frameworks. We obtain sensitivity to L-violation in the type-II seesaw model for triplet scalar masses up to 700 GeV and in the Zee model for charged scalar masses up to 4.8 TeV at the high-luminosity LHC with an integrated luminosity of 3 ab−1.

Partition functions for U(1) vectors and phases of scalar QED in AdS

We extend the computation of one-loop partition function in AdSd+1 using the method in [23] and [24] for scalars and fermions to the case of U(1) vectors. This method utilizes the eigenfunctions of the AdS Laplacian for vectors. For finite temperature, the partition function is obtained by generalizing the eigenfunctions so that they are invariant under the quotient group action, which defines the thermal AdS spaces. The results obtained match with those available in the literature. As an application of these results, we then analyze phases of scalar QED theories at one-loop in d = 2, 3. We do this first as functions of AdS radius at zero temperature showing that the results reduce to those in flat space in the large AdS radius limit. Thereafter the phases are studied as a function of the scalar mass and temperature. We also derive effective potentials and study phases of the scalar QED theories with N scalars.

Self-interacting forbidden dark matter under a cannibally co-decaying phase

In a usual dark matter (DM) model without a huge mass difference between the DM and lighter mediator, using the coupling strength suitable for having the correct relic density, the resulting self-interaction becomes several orders of magnitude smaller than that required to interpret the small-scale structures. We present a framework that can offer a solution for this point. We consider a model that contains the vector DM and a heavier but unstable Higgs-like scalar in the hidden sector. When the temperature drops below ~ mDM, the hidden sector, which is thermally decoupled from the visible sector, enters a cannibal phase, during which the DM density is depleted with the out-of-equilibrium decay of the scalar. The favored parameter region, giving the correct relic density and the proper size of self-interactions, shows the scalar-to-DM mass ratio ∈ [1.1, 1.33] and the scalar mass ∈ [9, 114] MeV. A sizable parameter space still survives the most current constraints and can be further probed by the near future NA62 beam dump experiment.

The Correlation Luminosity-Velocity Dispersion of Galaxies and Active Galactic Nuclei

In this work we discuss the correlation between luminosity L and velocity dispersion σ observed in different astrophysical contexts, in particular that of early-type galaxies (ETGs; Faber–Jackson (FJ) law) and that of active galactic nuclei (AGN). Our data for the ETGs confirm the bending of the FJ at high masses and the existence of similar curvatures in the projections of the Fundamental Plane (FP) approximately at the mass scale of ∼1010M⊙. We provide an explanation for such curvatures and for the presence of the Zone of Exclusion (ZoE) in these diagrams. The new prospected theory for the FJ law introduces a new framework to understand galaxy evolution in line with the hierarchical structure of the Universe. The classic analysis carried out for a class of type 1 AGN accreting gas at very high rates, confirms that a FJ law of the form L=L0σ4 is roughly consistent with the observations, with a slope quite similar to that of ETGs. We discuss the physics behind the FJ law for the AGN in different contexts and also examine the biases affecting both the luminosity and the velocity dispersion, paying particular attention to the effects induced by the spherical symmetry of the emitting sources on the accuracy of the luminosity estimates.