Heavy Mass Research Articles

Non-perturbative Lee-Wick gauge theory: Towards Confinement & RGE with strong couplings

We consider a non-Abelian Lee–Wick gauge theory and discuss Becchi-Rouet-Stora-Tyutin invariance. It contains fourth-order derivative as extensions of the kinetic term, leading to massive ghosts in the theory upon quantization. We particularly provide essential clues towards confinement conditions in strongly-coupled regimes, using the Kugo–Ojima approach, and obtain the functions in the non-perturbative regimes. This is achieved using a set of exact solutions of the corresponding local theory in terms of Jacobi elliptical functions. We obtain a similar function just as for the ordinary Yang-Mills theory but the main differences are that now, the cut-off arises naturally from the Lee–Wick heavy mass scales (M). We show that the fate of the ghosts are fixed in these regimes: they are no more the propagating degrees of freedom in the infrared-limit. As it also happens for the ordinary case, confinement is due to the non-Abelian nature of the theory. In the limit , one recovers the standard results for the local non-Abelian Yang-Mills theory.

Mechanism of enhanced ion temperature by impurity seeding in EAST H-mode plasma

Ion temperature (T i) profiles are commonly observed to increase in peaking, leading to higher central T i, after impurity seeding in the EAST H-mode plasma. Argon can be more efficient at raising T i than neon. Toroidal rotation can also be enhanced in scenarios with NBI heating. A more significant increase in toroidal rotation is brought about by seeding argon than seeding neon. Turbulence is experimentally observed to be suppressed. Extensive modeling using the quasilinear gyrokinetic code QuaLiKiz is performed to explain the above observations. It is found that the enhanced T i can always be explained by the turbulence stabilization. However, the mechanism of turbulence stabilization is related to heating methods and the seeding impurity species. In the pure RF (ECRH + LHW) heating scenarios, where only the trapped electron mode (TEM) exists, argon can stabilize the TEM more significantly than neon due to its higher charge and heavier mass. In scenarios with increasing NBI power, the ion heat flux can be dominated by the ion temperature gradient (ITG), thus the enhanced T i is mainly attributed to ITG stabilization. In these cases, except argon’s ability to more efficiently stabilize TEM, more evident increased toroidal rotation brought about by argon seeding can also be beneficial to stabilize turbulence.

NUCLEAR STRUCTURE STUDY OF THE HALO NUCLEI

The existence of halo nuclei is one of the major important discoveries in the field of nuclear physics. These nuclei are treated as loosely bound system in which a core of normal nuclear density is surrounded by so-called neutron (or proton) halo of diluted nuclear matter. Many theoretical investigations have attempted to understand these nuclei, which exist at light to heavy masses. The phenomenon of nuclear halo is a quantum effect that occurs in nuclei due to the presence of valence nucleons with low separation energy and I = 0, 1 (low angular momentum), and is manifested by the extraordinarily large radii of these nuclei. The core plus halo model is commonly used to describe halo nuclei. This model recognizes the need to treat the core and the halo neutrons or protons separately. By considering different model spaces for the core and the halo nucleons, we can better explain the properties of halo nuclei. This separation is justified by the fact that the valence nucleons in a halo nucleus have different properties compared to the core. Halo nuclei at rest cannot be used as target due to their short-lived species and extraordinary ratio of neutrons and protons (either neutron-rich or proton-rich). Instead, they can be studied through direct reactions with a radioactive isotope beam, employing inverse kinematics where the role of the beam and target are exchanged. In order to investigate the charge and matter densities of these nuclei, total and differential reaction cross section analyses of proton scattering on halo nuclei have been carried out using various theoretical and phenomenological methods

Post-Neutron Mass Yield Distribution in the Epi-Cadmium Neutron-Induced Fission of 233U

Post-neutron mass yield distribution in the epi-cadmium neutron-induced fission of 233U has been carried out by measuring the cumulative yields of various fission products within the mass ranges of 77 to 117 and 123 to 153 using an off-line gamma-ray spectrometric technique. Independent yields of a few fission products were also measured by using the same technique. Charge distribution correction has been applied on cumulative yields to obtain the post-neutron mass yields. The mass yield distribution parameters such as full-width at tenth-maximum of light and heavy mass wings, the average light mass <AL> and heavy mass <AH>, and the average number of neutrons <ν> were obtained. The spectrum average neutron energy is 1.9 MeV. Thus, the role of excitation energy on the nuclear structure effect was examined by comparing the mass yield data in between the epi-cadmium and thermal neutron–induced fission of 233U.

Three-loop b → sγ vertex with current-current operators

We compute three-loop vertex corrections to b → sγ induced by current-current operators. The results are presented as expansions in mc/mb with numerical coefficients which allow to cover all relevant values for the heavy quark masses in different renormalization schemes. Moreover we provide for the first time analytic results for the next-to-leading order contribution. Our results present an important building block to the next-to-next-to-leading order interference contributions of the current-current operators Q1 and Q2 with the electric dipole operator Q7.

Controlling crystal-electric field levels through symmetry-breaking uniaxial pressure in a cubic super heavy fermion

YbPtBi is one of the heavy-fermion systems with largest Sommerfeld coefficient γ and is thus classified as a ‘super’-heavy fermion material. In this work, we resolve the long-debated question about the hierarchy of relevant energy scales, such as crystal-electric field (CEF) levels, Kondo and magnetic ordering temperature, in YbPtBi. Through measurements of the a.c. elastocaloric effect and generic symmetry arguments, we identify an elastic level splitting that is unambiguously associated with the symmetry-allowed splitting of a quartet CEF level. This quartet, which we identify to be the first excited state at Δ/kB ≈ 1.6 K above the doublet ground state at ambient pressure, is well below the proposed Kondo temperature TK ≈ 10 K. Consequently, this analysis of the energy scheme can provide support models that predict that the heavy electron mass is a result of an enhanced degeneracy of the CEF ground state, i.e., a quasi-sextet in YbPtBi. At the same time, our study shows the potential of the a.c. elastocaloric effect to control and quantify strain-induced changes of the CEF schemes, opening a different route to disentangle the CEF energy scales from other relevant energy scales in correlated quantum materials.

Dai-Freed anomaly in the standard model and topological inflation

When we impose discrete symmetries in the standard model we have Dai-Freed global anomalies. However, interestingly if we introduce three right-handed neutrinos we can have an anomaly-free discrete Z4 gauge symmetry. This Z4 symmetry should be spontaneously broken down to the Z2 symmetry to generate the heavy Majorana masses for the right-handed neutrinos. We show that this symmetry breaking naturally generates topological inflation, which is consistent with the CMB observations at present and predicts a significant tensor mode with scalar-tensor ratio r > 0.03. The right-handed neutrinos play an important role in reheating processes. The reheating temperature is as high as ∼ 108 GeV, and non-thermal leptogenesis successfully takes place.

Supratransmission phenomenon in a Fermi-Pasta-Ulam diatomic lattice.

The nonlinear supratransmission phenomenon in a Fermi-Pasta-Ulam (FPU) diatomic lattice with two forbidden bands is investigated. Using a decoupling ansatz for the motion of the two different sublattices combined with the continuum (quasidiscrete) approximation, we derived analytically the threshold amplitudes of supratransmission occurrence when a sinusoidal driving with frequency in the upper forbidden band (lower forbidden band gap between acoustic and optical modes) is applied at one end. The resulting estimate of the threshold of a lattice with a first heavy particle is different to the one obtained from a lattice with a first light particle, showing the influence of the driven particle and giving also the possibility to have two thresholds on each forbidden gap of a diatomic lattice by switching the order of light (m) and heavy (M) masses. In the lower forbidden band, the dependence of the supratransmission threshold on the mass ratio (μ=m/M) has been evidenced and it appears that for large (small) values of μ, that is μ>60%, the coupling between the two modes must (must not) be considered. Numerical explorations were subsequently performed with an emphasis on the dependence of the threshold on the driving frequency and also on the mass of the driven particle (light or heavy). A good agreement is found between the numerical and analytical thresholds. For the limit case where all the masses are identical, the results of the monoatomic FPU previously found in the literature are recovered.

THE ATTEMPTS TO CLOSED LIFE SUPPORT SYSTEM DEVELOPMENT, THE EARLY CONTEXT OF MELISSA PROJECT

For more than 50 years, space actors are considering quitting the Earth orbit, and to elaborate a human mission to Mars. This type of mission, estimated to be longer than 1000 days, requires only to support human metabolism a high mass of resources not compatible of the launchers. Although, nowadays, the possibility of heavy mass launcher is proposed, a more elegant approach based on a high recycling is proposed. Many projects have been started with this objective. So far almost all had to stop after some years. In this publication the authors are trying to understand some of the reasons, which could be later-on recommendations for project developments and key decisions.

NNLL resummation of Sudakov shoulder logarithms in the heavy jet mass distribution

The heavy jet mass event shape has large perturbative logarithms near the leading order kinematic threshold at ρ=13\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\rho =\\frac{1}{3} $$\\end{document}. Catani and Webber named these logarithms Sudakov shoulders and resummed them at double-logarithmic level. A resummation to next-to-leading logarithmic level was achieved recently. Here, we extend the resummation using an effective field theory framework to next-to-next-to-leading logarithmic order and show how to combine it with the resummation of dijet logarithms. We also solve the open problem of an unphysical singularity in the resummed momentum space distribution, in a way similar to how it is resolved in the Drell-Yan qT spectrum: through a careful analysis of the kinematics and scale-setting in position space. The heavy jet mass Sudakov shoulder is the first observable that does not involve transverse momentum for which position space resummation is critical. These advances may lead to a more precise extraction of the strong coupling constant from e+e− data.

Sound transmission reduction of double walls using porous and viscoelastic materials

Double-walled structures separated by an acoustic cavity are widely used in many applications for sound insulation purposes. Their sound transmission loss is estimated by calculating the ratio between the incident sound power on the first wall and the radiated sound power by the second. The introduction of a melamine foam associated with heavy masses brings a better sound insulation against external noise. In this context, this work deals with the numerical prediction of the sound transmission of a roller shutter box equipped with porous and viscoelastic materials. Such system can be modeled, at first approximation, as a double-walled structure. The proposed approach is based on the use of the finite element method for the modeling of the different solid and fluid domains of the problem. A mixed displacement pressure formulation of the Biot poroelasticity equations is used to model the poroelastic domain. The structure is excited by a diffuse field represented by a superposition of plane waves with random phases and directions. The acoustic power radiated by the second wall is calculated by applying the Rayleigh integral method. The results show the importance of optimizing the position of the porous and the heavy layers to maximize the sound insulation.

Ultrasonic Bubble Cleaner as a Sustainable Solution

We aim to develop a floor-cleaning design by exploiting oscillating bubbles combined with ambient pressure waves to clean various surfaces. Previous studies of this method in lab settings have proven its efficacy, but practical applications, especially concerning real-world conditions like dirt surfaces, remain largely unprobed. Our findings indicate that, excluding a configuration with a heavy mass bottom transducer, all tested configurations achieved approximately 60–70% cleaning performance. A slight improvement in cleaning performance was observed with the introduction of microbubbles, although it was within the error margin. Particularly noteworthy is the substantial reduction in water consumption in configurations with a water pocket, decreasing from 280 mL to a mere 3 mL, marking a significant step toward more environmentally sustainable cleaning practices, such as reduced water usage. This research provides implications for real-world cleaning applications, promising an eco-friendly and efficient cleaning alternative that reduces water usage and handles a variety of materials without causing damage.

Numerical and experimental investigation of sound transmission through roller shutter boxes

Roller shutter boxes are essential components of building facades, providing crucial thermal and acoustic insulation. Conventional laboratory tests have been traditionally used to evaluate the sound transmission of roller shutter boxes. However, these tests can be expensive and lack repeatability and reproducibility, especially in the low-frequency range. To overcome these limitations, this study aims to introduce an advanced numerical model capable of accurately predicting the vibroacoustic response of roller shutter boxes and optimizing their acoustic insulation performance. The proposed numerical approach utilizes the finite element method to model the various solid and fluid domains within the roller shutter box structure. To capture the behavior of the poroelastic layers, a mixed displacement–pressure formulation of the Biot poroelasticity equations is employed. Excitation of the structure is achieved using a diffuse field comprising a superposition of plane waves with random phases and directions, while the resulting sound radiation is computed utilizing the infinite elements method. To validate the proposed numerical model, a comparison is made with results obtained from laboratory tests, and the experimental protocol is thoroughly described. The practical application of the proposed numerical method extends to the investigation of several influential factors on the acoustic behavior of roller shutter boxes, including assembly conditions, the positioning of poroelastic layers, and the inclusion of heavy masses.

On the decay mode Λb → Xsγ

We study the inclusive Hb→ Xsγ decay with Hb a beauty baryon, in particular Λb, employing an expansion in the heavy quark mass at Omb−3\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\mathcal{O}\\left({m}_b^{-3}\\right) $$\\end{document} at leading order in αs, keeping the dependence on the hadron spin. For a polarized baryon we compute the distribution d2ΓdydcosθP\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\frac{d^2\\Gamma}{dy\\ d\\cos {\ heta}_P} $$\\end{document}, with y = 2Eγ/mb, Eγ the photon energy and θP the angle between the baryon spin vector and the photon momentum in the Hb rest-frame. We discuss the correlation between the baryon and photon polarization, and show that effects of physics beyond the Standard Model can modify the photon polarization asymmetry. We also discuss a method to treat the singular terms in the photon energy spectrum obtained by the OPE.

Total kinetic energy release in the fast neutron induced fission of actinide nuclei

The total kinetic energy release and fission mass distributions for the fast neutron (En = 3–100 MeV) induced fission of 232Th, 233U, 235U, 237Np, 239Pu, 240Pu, and 242Pu have been measured using the LANSCE facility. The neutron energies were deduced from time-of- flight measurements. The fission fragments were detected using Si PIN diode detectors, giving us the fragment energies. The actinide targets were made by vapor deposition leading to high-quality targets, that were thin and uniform with reduced impurities. Corrections were made to the data for pulse height defect and the fragment energy loss in the target and its backing. The TKE distributions were Gaussian in shape and their mean value as a function of incoming neutron energy could be fitted with second order polynomials. In the case of 233U and 235U, our measurements agree with prior work. Our measurements for 232Th are unique. Our data agree with Viola scaling. The constant position of the heavy mass peak is interpreted as being due to the influence of the N = 88 and Z = 50 shells. The GEF model predictions agree with the data in general as do the CGMF model predictions.

Dead cone effect in charm and bottom quark jets

The evolution of a heavy quark initiated jet is mainly ruled by gluon bremsstrahlung. As a consequence of the dead-cone effect, this radiation is suppressed in the forward direction at angles smaller than that proportional to the heavy quark mass MQ, i.e. Θ0=MQ/EQ at energy EQ of the primary quark. In this paper, we unveil this effect in charm and bottom quark jets using DELPHI and OPAL data from Z0 boson decays in e+e− annihilation at center of mass energy 91.2 GeV. The analysis of the reconstructed heavy quark fragmentation function in momentum space shows the strong suppression of hadrons at high momenta in such events compared to light quark fragmentation by a factor ≲1/10. The amount of this suppression is well reproduced by perturbative QCD (pQCD) within the Modified Leading Logarithmic Aproximation and the compact scheme of Local Parton Hadron Duality (MLLA-LPHD). As a new result, we obtain an almost perfect agreement between the light quark fragmentation functions expected at W0∝MQ from DELPHI and OPAL data with Pythia8 and shed light on the reasons for the existence of the ultra-soft gluon excess at small momentum fraction in comparison with pQCD predictions.

Two interacting electrons in N-dimensional quantum dot with generalized cornell potential

In this work, the interacting electrons in N-dimensional quantum dot with generalized Cornell potential in the presence of an external magnetic field are investigated using the Laplace transformation method. The energy eigenvalues and the corresponding normalized wave functions are calculated. The parameter defining the force of a constant traction on the electrons is quantified and represents well the negative of the electric force. The spectrum for some special cases of the generalized Cornell potential is obtained. One of the applications of such models is the calculation of heavy quarkonia mass spectra. We have calculated these masses and the current results are in agreement with the experimental data.

Muon puzzle in inclined muon bundles detected by NEVOD-DECOR

The data of cosmic ray NEVOD-DECOR experiment on the investigation of inclined muon bundles for a long time period (May 2012 - March 2021) are presented. The analysis showed that the observed intensity of muon bundles at primary cosmic ray energies of about 1 EeV and higher can be compatible with the expectation in frame of widely used hadron interaction models only under the assumption of an extremely heavy mass composition. This conclusion is consistent with data of several experiments on investigations of muon content in air showers, but contradicts the available fluorescence data on X_{max}Xmax which favor a light mass composition at these energies. In order to clarify the nature of the "muon puzzle", investigations of the muon bundle energy deposit in the detector material were carried out. For the first time, experimental estimates of the average energy of muons in the bundles of inclined air showers initiated by primary particles with energies from 10 to 1000 PeV have been obtained.

NANOGrav meets Hot New Early Dark Energy and the origin of neutrino mass

It has recently been speculated that the NANOGrav observations point towards a first-order phase transition in the dark sector at the GeV scale [1]. Here, we show that such a phase transition might already have been predicted in the Hot New Early Dark Energy model (Hot NEDE) [2,3]. There, it was argued that two dark sector phase transitions are the signature of neutrino mass generation through the inverse seesaw mechanism. In particular, an IR phase transition serves a double purpose by resolving the Hubble tension through an energy injection and generating the Majorana mass entry in the inverse seesaw mixing matrix. This usual NEDE phase transition is then accompanied by a UV counterpart, which generates the heavy Dirac mass entry in the inverse seesaw mass matrix of a right-handed neutrino. Here, we investigate if the UV phase transition of the Hot NEDE model can occur at the GeV scale in view of the recent NANOGrav observations.

Beyond lepton number violation at the HL-LHC: resolving heavy neutrino-antineutrino oscillations

Collider testable low-scale seesaw models predict pseudo-Dirac heavy neutrinos, that can produce an oscillating pattern of lepton number conserving and lepton number violating events. We explore if such heavy neutrino-antineutrino oscillations can be resolved at the HL-LHC. To that end, we employ the first ever full Monte Carlo simulation of the oscillations, for several example benchmark points, and show under which conditions the CMS experiment is able to discover them. The workflow builds on a FeynRules model file for the phenomenological symmetry protected seesaw scenario (pSPSS) and a patched version of MadGraph, able to simulate heavy neutrino-antineutrino oscillations. We use the fast detector simulation Delphes and present a statistical analysis capable of inferring the significance of oscillations in the simulated data. Our results demonstrate that, for heavy neutrino mass splittings smaller than about 100 μeV, the discovery prospects for heavy neutrino-antineutrino oscillation at the HL-LHC are promising.