Search

Unlike in 4k dimensions, the action of charge conjugation operator in 4k + 2 dimensions preserves spinor chirality. This property, in a generic orbifolded geometry (of scale 1 / R ∼ O (1 TeV)) with KK number conservation, leads to baryon number violating operators with KK fermion modes. These exotic operators can be mapped on to the 4D operators responsible for proton decay and hydrogen–antihydrogen oscillation by introducing the KK-1 hypercharge gauge boson interaction. This KK-1 hypercharge gauge boson, being the lightest, is stable and is the ideal dark matter (DM) candidate in the model. Hence, dark matter becomes a crucial ingredient in facilitating the proton decay and Δ B = 2 = Δ L processes. Thus, this model answeres the lack of their evidence in terrestrial experiments owing to the low density of dark matter on Earth. Nevertheless, though terrestrial experiments are not yet sensitive to dark matter influenced baryon number violations, their rates can be substantially enhanced in dense DM clusters at the centre of galaxies. [ABSTRACT FROM AUTHOR]

In this work, we explore the possibility of the n – n ¯ oscillation accompanied by CP-violation in the presence of magnetic fields. The n – n ¯ oscillation, which violates the baryon number ( B ) by two units ( ∣ Δ B ∣ = 2 ), can originate from the mixing between the neutron (n) and the neutral elementary particle (η) and may give rise to non-trivial physical consequences that can be testable in future experiments. We show that the probability of the n – n ¯ oscillation can be greatly enhanced by properly adjusting the magnetic field. In particular, the peak values of the oscillation probability in the presence of resonance magnetic fields can be 8–10 orders of magnitude higher than that in the absence of magnetic fields. We point out that there might not be sizable CP-violating effects in the n – n ¯ oscillation unless the mass of η is close to the mass of the neutron. We also analyze the interplay among various parameters associated with both B -violation and CP-violation and attempt to disentangle the effects of such parameters. The n – n ¯ oscillation process accompanied by CP-violation may open a promising avenue for exploring new physics beyond the Standard Model (SM). [ABSTRACT FROM AUTHOR]

Quark–Gluon plasma driven by the strong force is subject to the conservativeness of the baryon number, net electric charge, strangeness, etc. However, the fluctuations around their mean values at specific temperatures and chemical potentials can provide viable signals for the production of Quark–Gluon plasma. These fluctuations can be captured theoretically as moments of different orders in the expansion of pressure or the thermodynamic potential of the system under concern. Here, we look for possible explanations in the methodologies used for capturing them by using the framework of the Polyakov–Nambu–Jona-Lasinio (PNJL) model under the 2 + 1 flavor consideration with mean-field approximation. The various quantities thus explored can act to signify meaningfully near the phase transitions. Justifications are also made for some of the quantities capable of serving necessarily under experimental scenarios. Additionally, variations in certain quantities are also made for the different collision energies explored in the high-energy experiments. Rectification of the quantitative accuracy, especially in the low-temperature hadronic sector, is of prime concern, and it is also addressed. It was found that most of the observables stay in close proximity with the existing lattice QCD results at the continuum limit, with some artifacts still remaining, especially in the strange sector, which needs further attention. [ABSTRACT FROM AUTHOR]

We investigate the rapidity spectra of protons in central Ar+Sc and Pb+Pb collisions at Conseil Européen pour la Recherche Nucléaire (CERN) super proton synchrotron (SPS) energies, utilizing the HIJING code integrated with the advanced popcorn (AP) mechanism from PYTHIA6.4. We find that the standard HIJING/AP model is inadequate for fully capturing the proton rapidity distributions observed in these collisions. To overcome this, we focus on the leading diquark (LD) break-up component, distinguishing between diquark preserving and diquark breaking (DB) behaviors. Our analysis reveals that the suppressed DB component is essential for accurately describing the proton and neutron x F spectra, particularly noting an excess of baryon number at lower x F values consistent with experimental observations. By integrating the suppressed LD break-up mechanism, informed by pp and Be+Be collision data, we successfully replicate the proton rapidity spectra and also effectively capture the rapidity spectra of negative pions and charged kaons for the studied reactions. These outcomes underscore the critical role of the suppressed LD break-up component in elucidating the mechanisms of baryon production and stopping in heavy-ion collisions at CERN SPS energies. [ABSTRACT FROM AUTHOR]

We study cold strange quark stars employing an enhanced version of the quark-mass density-dependent model, which incorporates excluded volume effects to address non-perturbative QCD repulsive interactions. We provide a comparative analysis of our mass formula parametrization with previous models from the literature. We identify the regions within the parameter space where three-flavor quark matter is more stable than the most tightly bound atomic nucleus (stability window). Specifically, we show that excluded volume effects do not change the Gibbs free energy per baryon at zero pressure, rendering the stability window unaffected. The curves of pressure versus energy density exhibit various shapes—convex upward, concave downward, or nearly linear—depending on the mass parametrization. This behavior results in different patterns of increase, decrease, or constancy in the speed of sound as a function of baryon number density. We analyze the mass–radius relationship of strange quark stars, revealing a significant increase in maximum gravitational mass and a shift in the curves toward larger radii as the excluded volume effect intensifies. Excluded volume effects render our models compatible with all modern astrophysical constraints, including the properties of the recently observed low-mass compact object HESSJ1731. [ABSTRACT FROM AUTHOR]

The existence of dibaryons, the systems with baryon number two, is one of the central questions in modern nuclear physics. It is closely connected with the problem of phase transitions in nuclear matter, various manifestations of which are being searched for in the experiments with colliding heavy nuclei. Since the theory of these processes is very difficult, the interpretation of such data usually contains large uncertainties. At the same time there is a possibility of understanding some features of these processes in the collision of the lightest nuclei–deuterons. Exploring such an opportunity at the future NICA SPD is the focus of this paper. It is shown that while using Kinematical fit technique at the simulation of the process below meson production threshold, the accuracy of the estimation of the mass is on the level 2–3 MeV/ when the deuteron moment of the NICA Collider is equal to 2.6 GeV/c (below is used as a mass of , i.e. , where , are deuteron mass and excitation energy). The system is called sometimes as dibaryons below. [ABSTRACT FROM AUTHOR]

We investigate a crossover quantum chromodynamical (QCD) phase transition that occurred in the early Universe and explore a potential formation scenario for stable strangeon nuggets during this process. To analyze the thermodynamics of the QCD phase involving u, d, s quarks, we employ the Polyakov–Nambu–Jona-Lasinio model, while the relativistic mean-field model is used to describe the hadronic matter. We consider the participation of strangeons (strange quark clusters with net strangeness) in the quark-hadron phase transition process. During this process, strangeon nuggets are formed, and larger nuggets could survive after the phase transition. The crossover phase transition from quarks to hadrons occur at a cosmic temperature of approximately T ∼ 1 7 0 MeV, and these two phases (quark phase and strangeon nugget-hadronic phase) are connected in a three-window model. We introduce a distribution function of the nugget baryon number, A, to describe the nugget's number density (equivalent to the mass spectrum). All strangeon nuggets with A > A c are considered to be stable, where the critical number, A c , is determined by both weak and strong interactions. To calculate the thermodynamics of stable strangeon nuggets, a nonrelativistic equation of state was applied, resulting in negligible thermodynamic contributions (pressure, entropy, etc.) compared to the hadronic part. Our study shows that the mass fraction of the strangeon nuggets that survived from the early Universe is comparable to dark matter, suggesting a possible explanation for cold dark matter without introducing any exotic particles beyond the Standard Model. [ABSTRACT FROM AUTHOR]

This document provides an overview of the PREX and CREX experiments, which aimed to measure the neutron skin thickness in lead-208 and calcium-48 nuclei using the weak force. The results of these experiments revealed a thick neutron skin for lead-208 and a surprisingly thin skin for calcium-48, challenging current theoretical frameworks. The implications of these findings for understanding the structure and composition of neutron stars are also discussed. The document emphasizes the importance of collaboration between theoretical and experimental groups to further investigate these complex nuclear structures. [Extracted from the article]

We solve the particle-antiparticle and cosmological constant problems proceeding from quantum theory, which postulates that: various states of the system under consideration are elements of a Hilbert space H with a positive definite metric; each physical quantity is defined by a self-adjoint operator in H ; symmetry at the quantum level is defined by a representation of a real Lie algebra A in H such that the representation operator of any basis element of A is self-adjoint. These conditions guarantee the probabilistic interpretation of quantum theory. We explain that in the approaches to solving these problems that are described in the literature, not all of these conditions have been met. We argue that fundamental objects in particle theory are not elementary particles and antiparticles but objects described by irreducible representations (IRs) of the de Sitter (dS) algebra. One might ask why, then, experimental data give the impression that particles and antiparticles are fundamental and there are conserved additive quantum numbers (electric charge, baryon quantum number and others). The reason is that, at the present stage of the universe, the contraction parameter R from the dS to the Poincare algebra is very large and, in the formal limit R → ∞ , one IR of the dS algebra splits into two IRs of the Poincare algebra corresponding to a particle and its antiparticle with the same masses. The problem of why the quantities (c , ℏ , R) are as are does not arise because they are contraction parameters for transitions from more general Lie algebras to less general ones. Then the baryon asymmetry of the universe problem does not arise. At the present stage of the universe, the phenomenon of cosmological acceleration (PCA) is described without uncertainties as an inevitable kinematical consequence of quantum theory in semiclassical approximation. In particular, it is not necessary to involve dark energy the physical meaning of which is a mystery. In our approach, background space and its geometry are not used and R has nothing to do with the radius of dS space. In semiclassical approximation, the results for the PCA are the same as in General Relativity if Λ = 3 / R 2 , i.e., Λ > 0 and there is no freedom for choosing the value of Λ. [ABSTRACT FROM AUTHOR]

Recently, the rapidity-odd directed flow ( v 1 ) of produced hadrons ( K − , ϕ , p ¯ , Λ ¯ , Ξ ¯ + , Ω − , and Ω ¯ + ) has been studied. Several combinations of these produced hadrons, with very small mass differences but differences in the net electric charge ( Δ q ) and net strangeness ( Δ S ) on the two sides, have been considered. A difference in v 1 between the two sides of these combinations ( Δ v 1 ) has been proposed as a consequence of the electromagnetic field produced in relativistic heavy-ion collisions, especially if Δ v 1 increases with Δ q . Our study is performed to understand the effect of the coalescence sum rule (CSR) on Δ v 1 . We point out that the CSR leads to Δ v 1 = c q Δ q + c S Δ S , where the coefficients c q and c S reflect the Δ v 1 of produced quarks. Equivalently, one can write Δ v 1 = c q Δ q + c B Δ B , involving the difference in the net baryon number Δ B , where the CSR gives c B = − 3 c S . We then propose two methods to extract the coefficients for the Δ q and Δ S dependences of Δ v 1 . [ABSTRACT FROM AUTHOR]

The ground state of QCD with two flavors at a finite baryon chemical potential under rapid rotation is a chiral soliton lattice (CSL) of the η meson, consisting of a stack of sine-Gordon solitons carrying a baryon number, due to the anomalous coupling of the η meson to the rotation. In a large parameter region, the ground state becomes a non-Abelian CSL, in which due to the neutral pion condensation each η soliton decays into a pair of non-Abelian sine-Gordon solitons carrying S2 moduli originated from Nambu-Goldstone (NG) modes localized around it, corresponding to the spontaneously broken vector symmetry SU(2)V. There, the S2 modes of neighboring solitons are anti-aligned, and these modes should propagate in the transverse direction of the lattice due to the interaction between the S2 modes of neighboring solitons. In this paper, we calculate excitations including gapless NG modes and excited modes around non-Abelian and Abelian (η) CSLs, and find three gapless NG modes with linear dispersion relations (type-A NG modes): two isospinons (S2 modes) and a phonon corresponding to the spontaneously broken vector SU(2)V and translational symmetries around the non-Abelian CSL, respectively, and only a phonon for the Abelian CSL because of the recovering SU(2)V. We also find in the deconfined phase that the dispersion relation of the isospinons becomes of the Dirac type, i.e. linear even at large momentum. [ABSTRACT FROM AUTHOR]

Based on the chiral perturbation theory at the leading order, we show a signal of the presence of a new phase in rapidly rotating QCD matter with two flavors, that is a domain-wall Skyrmion phase. Based on the chiral Lagrangian with a Wess-Zumino-Witten (WZW) term responsible for the chiral anomaly and chiral vortical effect, it was shown that the ground state is a chiral soliton lattice (CSL) consisting of a stack of η-solitons in a high density region under rapid rotation. In a large parameter region, a single η-soliton decays into a pair of non-Abelian solitons, each of which carries SU(2)V/U(1) ≃ ℂP1 ≃ S2 moduli as a consequence of the spontaneously broken vector symmetry SU(2)V. In such a non-Abelian CSL, we construct the effective world-volume theory of a single non-Abelian soliton to obtain a d = 2 + 1 dimensional ℂP1 model with a topological term originated from the WZW term. We show that when the chemical potential is larger than a critical value, a topological lump supported by the second homotopy group π2(S2) ≃ ℤ has negative energy and is spontaneously created, implying the domain-wall Skyrmion phase. This lump corresponds in the bulk to a Skyrmion supported by the third homotopy group π3[SU(2)] ≃ ℤ carrying a baryon number. This composite state is called a domain-wall Skyrmion, and is stable even in the absence of the Skyrme term. An analytic formula for the effective nucleon mass in this medium can be written only in terms of the meson's constants as 4 2 π f π f η / m π ~ 1.21 GeV with the decay constants fπ and fη of the pions and η meson, respectively, and the pion mass mπ. This is reasonably heavier than the nucleon mass in the QCD vacuum. [ABSTRACT FROM AUTHOR]

Tensions in the measurements of neutron and kaon weak decays, such as of the neutron lifetime, may speak to the existence of new particles and dynamics not present in the Standard Model (SM). In scenarios with dark sectors, particles that couple feebly to those of the SM appear. We offer a focused overview of such possibilities and describe how the observations of neutron stars, which probe either their structure or dynamics, limit them. In realizing these constraints, we highlight how the assessment of particle processes within dense baryonic matter impacts the emerging picture—and we emphasize both the flavor structure of the constraints and their broader connections to cogenesis models of dark matter and baryogenesis. [ABSTRACT FROM AUTHOR]

The Generalized Uncertainty Principle (GUP) is motivated by the premise that spacetime fluctuations near the Planck scale impose a lower bound on the achievable resolution of distances, leading to a minimum length. Inspired by a semiclassical method that integrates the GUP into the partition function by deforming its phase space, we induce a modification on the thermodynamic quantities of the MIT bag model that we propose serves as an effective semiclassical description of deconfined quark matter in a space with minimal length. We investigate the consequences of this deformation on the zero‐temperature limit, revealing a saturation limit for the energy density, pressure, and baryon number density and an overall decrease of the thermodynamic quantities which suggests an enhanced stability against gravitational collapse. These findings extend existing research on GUP‐deformed Fermi gases. Ultimately, our description introduces the effects of quantum gravity in the equations of state for compact stars in a mathematically simple manner, suggesting the potential for extension to more complex systems. [ABSTRACT FROM AUTHOR]

The article explores the possibility of a mesonic nuclear state and discusses the presence of exotic forms of hadrons. It describes an experiment conducted to search for a kaonic nuclear bound state and discusses the formation and decay processes of the particle "K-pp." The study focuses on the advantages of studying the invariant mass of the particle and the ability to deduce the invariant mass and momentum transfer from the initial K-meson. The authors observe a clear peak formation below the kaon binding threshold, indicating the presence of a kaonic nuclear bound state. This is the first convincing signal that a K-meson can form a nuclear bound state with two nucleons. The state has a large binding energy but is unstable and decays through the strong interaction. The study of light kaonic nuclei is important for understanding the strong interaction and exploring physics beyond normal nuclear density. [Extracted from the article]

In this review article, we revisit the topic of baryogenesis, which is the physical process that generated the observed baryon asymmetry during the first stages of the primordial Universe. A viable theoretical explanation to understand and investigate the mechanisms underlying baryogenesis must always ensure that the Sakharov criteria are fulfilled. These essentially state the following: (i) baryon number violation; (ii) the violation of both C (charge conjugation symmetry) and CP (the composition of parity and C); (iii) and the departure from equilibrium. Throughout the years, various mechanisms have been proposed to address this issue, and here we review two of the most important, namely, electroweak baryogenesis (EWB) and Grand Unification Theories (GUTs) baryogenesis. Furthermore, we briefly explore how a change in the theory of gravity affects the EWB and GUT baryogenesis by considering Scalar–Tensor Theories (STT), where the inclusion of a scalar field mediates the gravitational interaction, in addition to the metric tensor field. We consider specific STT toy models and show that a modification of the underlying gravitational theory implies a change in the time–temperature relation of the evolving cosmological model, thus altering the conditions that govern the interplay between the rates of the interactions generating baryon asymmetry, and the expansion rate of the Universe. Therefore, the equilibrium of the former does not exactly occur as in the general relativistic standard model, and there are consequences for the baryogenesis mechanisms that have been devised. This is representative of the type of modifications of the baryogenesis processes that are to be found when considering extended theories of gravity. [ABSTRACT FROM AUTHOR]

Asymptotic Grand Unification theories (aGUTs) in five dimensions provide a valid alternative to standard quantitative unification. We define the pathway towards viable models starting from a general unified bulk gauge symmetry. Imposing the presence of ultra-violet fixed points for both gauge and Yukawa couplings strongly limits the possibilities. Within the SU(N) kinship, we identify and characterise only two realistic minimal models, both based on a bulk SU(6) symmetry. Both models feature the generation of either up or down-type Yukawas via gauge scalars, two Higgs doublets with build-in minimal flavour violation at low energies, and conservation of baryon number. We also propose interesting avenues beyond the minimality criterion. [ABSTRACT FROM AUTHOR]

Various models of tetraquark generation in the reaction are considered. The predictions for corresponding inclusive spectra were evaluated at the energies 32 and 250 GeV. [ABSTRACT FROM AUTHOR]

Motivated by the neutron lifetime puzzle, it is proposed that neutrons may decay into new states yet to be observed. We review the neutron star constraints on dark fermions carrying unit baryon number with masses around 939 MeV, and discuss the interaction strengths required for the new particle. The possibility of neutrons decaying into three dark fermions is investigated. While up to six flavors of dark quarks with masses around 313 MeV can be compatible with massive pulsars, any such exotic states lighter than about 270 MeV are excluded by the existence of low-mass neutron stars around ∼ 1.2 M ⊙ . Light dark quarks in the allowed mass range may form a halo surrounding normal neutron stars. We discuss the potential observable signatures of the halo during binary neutron star mergers. [ABSTRACT FROM AUTHOR]

It is possible that the proton is stable while atomic hydrogen is not. This is the case in models with new particles carrying baryon number which are light enough to be stable themselves, but heavy enough so that proton decay is kinematically blocked. Models of new physics that explain the neutron lifetime anomaly generically have this feature, allowing for atomic hydrogen to decay through electron capture on a proton. We calculate the radiative hydrogen decay rate involving the emission of a few hundred keV photon, which makes this process experimentally detectable. In particular, we show that the low energy part of the Borexino spectrum is sensitive to radiative hydrogen decay, and turn this into a limit on the hydrogen lifetime of order 10 30 s or stronger. For models where the neutron mixes with a dark baryon, χ , this limits the mixing angle to roughly 10 − 11 , restricting the n → χ γ branching to 10 − 4 , over a wide range of parameter space. [ABSTRACT FROM AUTHOR]

Since for baryons and leptons, positive numbers represent matter and negative numbers represent antimatter, the consequence of ( I B i - I L i ) conservation is that baryons can convert into antimatter leptons and antimatter baryons can convert into matter leptons; for example, a proton could convert into a positron (antimatter electron). When the expansion of the universe dropped the photon energy below 1.022 MeV, electron/positron production ceased, nominally locking in the universe as being a bath of photons, electrons, and positrons. The universe would also contain neutrinos, the production of which is beyond this article, as well as a few protons and antimatter protons that were created by chance encounter by triplets of quarks or antiquarks. It predicted the existence of what we now call antimatter.[4] Antimatter is the opposite of matter.[5] When matter and antimatter are combined, they annihilate into a substantial amount of energy. [Extracted from the article]

There is no reason why the gauge symmetry extension is family universal as in the standard model and the most well-motivated models, e.g. left-right symmetry and grand unification. Hence, we propose a simplest extension of the standard model – a flavor-dependent U(1) gauge symmetry – and find the new physics insight. For this aim, the U(1) charge, called X, is expressed as X = x B + y L in which x and y are free parameters as functions of flavor index, e.g. for a flavor i they take x i and y i respectively, where B and L denote normal baryon and lepton numbers. Imposing a relation involved by the color number 3, i.e. - x 1 , 2 , ... , n = x n + 1 , n + 2 , ... , n + m = 3 y 1 , 2 , ... , n + m ≡ 3 z , for arbitrarily nonzero z, we achieve a novel U(1) theory with implied X-charge. This theory not only explains the origin of the number of observed fermion families but also offers a possible solution for both neutrino mass and dark matter, which differs from B - L extension. Two typical models based on this idea are examined, yielding interesting results for flavor-changing neutral currents and particle colliders, besides those of neutrino mass and dark matter. [ABSTRACT FROM AUTHOR]

A new method is introduced to construct approximations to Skyrmions that are explicit rational functions of the spatial Cartesian coordinates. The scheme uses ADHM data of a Yang–Mills instanton to produce a Skyrmion with a baryon number that is equal to the instanton number. The formula for the Skyrmion involves only the evaluation of the ADHM data, in contrast to the Atiyah–Manton construction that requires the solution of a differential equation that can only be solved explicitly in the case of a spherically symmetric Skyrmion. Examples with baryon numbers one and two are studied in detail. The energy of the rational Skyrmion with baryon number one is lower than that of the Atiyah–Manton Skyrmion, which is already within one percent of the energy of the true numerically computed Skyrmion. A family of baryon number two Skyrmions is presented, which includes an axially symmetric Skyrmion that smoothly transforms to a pair of well-separated single Skyrmions as the parameter is varied. [ABSTRACT FROM AUTHOR]

The crystalline structure of nuclear matter is investigated in the standard Skyrme model with massive pions. A semi-analytic method is developed to determine local minima of the static energy functional with respect to variations of both the field and the period lattice of the crystal. Four distinct Skyrme crystals are found. Two of these were already known–the cubic lattice of half-skyrmions and the α-particle crystal–but two are new. These new solutions have lower energy per baryon number and less symmetry, being periodic with respect to trigonal but not cubic period lattices. Minimal energy crystals are also constructed under the constraint of constant baryon density, and it is shown that the two new non-cubic crystals tend to chain and multi-wall solutions at low densities. [ABSTRACT FROM AUTHOR]

The centrality determination and the estimated fluctuations of number of participant nucleons N part in Au–Au collisions at 1.23 AGeV beam kinetic energy suffers from severe model dependencies. Comparing the Glauber Monte Carlo (MC) and UrQMD transport models, it is shown that N part is a strongly model dependant quantity. In addition, for any given centrality class, Glauber MC and UrQMD predicts drastically different N part distributions. The impact parameter b and the number of charged particles N ch on the other hand are much more correlated and give an almost model independent centrality estimator. It is suggested that the total baryon number balance, from integrated rapidity distributions, can be used instead of N part in experiments. Preliminary HADES data show significant differences to both, UrQMD simulations and STAR data in this respect. [ABSTRACT FROM AUTHOR]

We study baryogenesis in a hybrid inflation model which is embedded to the minimal supersymmetric model with right-handed neutrinos. Inflation is induced by a linear combination of the right-handed sneutrinos and its decay reheats the universe. The decay products are stored in conserved numbers, which are transported under the interactions in equilibrium as the temperature drops down. We find that at least a few percent of the initial lepton asymmetry is left under the strong wash-out due to the lighter right-handed (s)neutrinos. To account for the observed baryon number and the active neutrino masses after a successful inflation, the inflaton mass and the Majorana mass scale should be 1013 GeV and O (109–1010) GeV, respectively. [ABSTRACT FROM AUTHOR]

We develop an action principle to construct the field equations for dissipative/resistive general relativistic two-temperature plasmas, including a neutrally charged component. The total action is a combination of four pieces: an action for a multifluid/plasma system with dissipation/resistivity and entrainment; the Maxwell action for the electromagnetic field; the Coulomb action with a minimal coupling of the four-potential to the charged fluxes; and the Einstein–Hilbert action for gravity (with the metric being minimally coupled to the other action pieces). We use a pull-back formalism from spacetime to abstract matter spaces to build unconstrained variations for the neutral, positively, and negatively charged fluid species and for three associated entropy flows. The full suite of field equations is recast in the so-called " 3 + 1 " form (suitable for numerical simulations), where spacetime is broken up into a foliation of spacelike hypersurfaces and a prescribed "flow-of-time". A previously constructed phenomenological model for the resistivity is updated to include the modified heat flow and the presence of a neutrally charged species. We impose baryon number and charge conservation as well as the Second Law of Thermodynamics in order to constrain the number of free parameters in the resistivity. Finally, we take the Newtonian limit of the " 3 + 1 " form of the field equations, which can be compared to existing non-relativistic formulations. Applications include main sequence stars, neutron star interiors, accretion disks, and the early universe. [ABSTRACT FROM AUTHOR]

We explore the effective theory of an axion in a gauged baryon number symmetry extension of the Standard Model (SM), where the axion is realized from a Dine-Fischler-Srednicki-Zhitnitsky (DFSZ) model construction. Integrating out the anomalons realizes a pattern of effective Wilson coefficients reflecting the factorization between the anomalous Peccei-Quinn and gauged baryon number symmetries. We construct and analyze the chiral transformation invariance of the axion effective theory, accounting for possible flavor-violating axion couplings. We calculate and study the unique phenomenology of the axion and Z′ boson, and we present the current collider limits on these particles in the m Z ′ g B , {ma, Gaγγ}, and m a f a − 1 planes. [ABSTRACT FROM AUTHOR]

The production mechanism of multiquark exotic hadrons in high energy multiproduction processes lies in the structure of the relevant exotic hadrons as well as in some important aspects of high energy scattering, such as multi-parton interactions, underlying events, etc. At mass pole around 2900 MeV, a family of open charm tetraquarks,  T c s s and  T c s ¯ s, are observed in B decay. They are also suitable for study in multiproduction processes to obtain more information on their structure. If these resonances are produced as compact four-quark states, one can predict the production properties based on the similarities in their production mechanism to those of  Ξ c ,  Σ c , and  Λ c . Physics implies that the colour and baryon number fluctuations of the preconfinement system in high energy scattering can enhance both the baryon and four-quark state production rates via 'diquark fragmentation'. We calculate the production properties of the tetraquark family  T c s s and  T c s ¯ s at LHC energy for the forthcoming LHC measurements. [ABSTRACT FROM AUTHOR]

Quark has an electric charge either - 1 / 3 or 2/3 and a baryon number 1/3, where the divisions 3's match the color number. Although the electric charge and the baryon number have a nature distinct from the color charge, the matching is necessary for the standard model or a relevant B - L extension consistent at quantum level, since the relevant anomaly [ S U (2) L ] 2 U (1) A for A = Y or B - L must vanish. If elementary particles have a new U(1) charge differently from A, such anomaly is not cancelled for each family. However, if we demand that the anomaly is cancelled over all families, this relates the color number to the family number instead of the electric charge and baryon number, and interestingly the family number guides us to a novel U(1) theory. We will discuss the implication of this theory for neutrino mass, recent W-boson mass anomaly, FCNC, and particle colliders. [ABSTRACT FROM AUTHOR]

Renormalization group evolution above the electroweak scale is a crucial ingredient in the phenomenology of the Standard Model Effective Theory. The RGESolver open-source C++ library performs the evolution at leading order for dimension-six operators in the most general flavour scenario (assuming lepton and baryon number conservation). Given its efficiency, RGESolver can be used to include the effects of renormalization group evolution in extensive phenomenological analyses in the framework of the Standard Model Effective Theory. [ABSTRACT FROM AUTHOR]

Tensions in the measurements of neutron and kaon weak decays, such as of the neutron lifetime, may speak to the existence of new particles and dynamics not present in the Standard Model (SM). In scenarios with dark sectors, particles that couple feebly to those of the SM appear. We offer a focused overview of such possibilities and describe how the observations of neutron stars, which probe either their structure or dynamics, limit them. In realizing these constraints, we highlight how the assessment of particle processes within dense baryonic matter impacts the emerging picture—and we emphasize both the flavor structure of the constraints and their broader connections to cogenesis models of dark matter and baryogenesis.

A 5th force coupling to baryon number B has been proposed to account for the correlations between the acceleration differences Δ a i j of the samples studied in the Eötvös experiment, and the corresponding differences in the baryon-to-mass ratios Δ (B ∕ μ) i j . To date the Eötvös results have not been supported by modern experiments. Here, we investigate the phenomenological implications of a possible magnetic analog ℬ 5 of the conventional 5th force electric field, ℰ 5 , arising from the Earth's rotation. We demonstrate that, in the presence of couplings proportional to ℬ 5 , both the magnitude and direction of a possible 5th force field could be quite different from what would otherwise be expected and warrants further investigation. [ABSTRACT FROM AUTHOR]

We explore the presence of thermodynamic instabilities and, consequently, the realization of a pure hadronic phase transition in the hot and finite baryon density nuclear matter. The analysis is performed by means of an effective relativistic mean-field model with the inclusion of hyperons, Δ -isobars, and the lightest pseudoscalar and vector meson degrees of freedom. The Gibbs conditions on the global conservation of baryon number and zero net strangeness in symmetric nuclear matter are required. Similarly to the liquid–gas phase transition, we show that a phase transition, characterized by mechanical instabilities (due to fluctuations on the baryon number) and chemical-diffusive instabilities (due to fluctuations on the strangeness number), can take place for a finite range of Δ -meson coupling constants, compatible with different experimental constraints. The hadronic phase transition, which presents similar features to the quark-hadron phase transition, is characterized by different strangeness content during the mixed phase and, consequently, by a sensible variation of the strange anti-particle to particle ratios. [ABSTRACT FROM AUTHOR]

We present a pedagogical introduction to the electroweak baryogenesis. The review focuses principally on the sphaleron and baryon number (non)-conservation or chiral anomaly. All results are derived with details for a self-contained reading. [ABSTRACT FROM AUTHOR]

Motivated by the work of Paliathanasis et al. (A. Paliathanasis and G. Leon, "Cosmological solutions in Hořava–Lifshitz scalar field theory," ZnA, vol. 75, p. 523, 2020), this work reports the baryogenesis in Hořava–Lifshitz cosmology by taking the background evolution as modified Chaplygin gas and modified holographic dark energy. The Starobinsky potential has been selected to initiate the study. The scalar field and its potential have been reconstructed and found to be consistent with the universe's expansion. The quintessence behaviour of equation of state parameters has been observed for both cases. Finally, baryogenesis has been studied in both cases. The baryon entropy ratio attained the observed value. It is also well explained that either the model will achieve an equal number of baryon and antibaryon densities or will satisfy the Generalized Second Law of Thermodynamics. [ABSTRACT FROM AUTHOR]

It was previously shown within chiral perturbation theory that the ground state of QCD in a sufficiently large magnetic field and at nonvanishing, but not too large, baryon chemical potential is a so-called chiral soliton lattice. The crucial ingredient of this observation was the chiral anomaly in the form of a Wess-Zumino-Witten term, which couples the baryon chemical potential to the magnetic field and the gradient of the neutral pion field. It was also shown that the chiral soliton lattice becomes unstable towards charged pion condensation at larger magnetic fields. We point out that this instability bears a striking resemblance to the second critical magnetic field of a type-II superconductor, however with the superconducting phase appearing upon increasing the magnetic field. The resulting phase has a periodically varying charged pion condensate that coexists with a neutral pion supercurrent. We construct this phase analytically in the chiral limit and show that it is energetically preferred. Just like an ordinary type-II superconductor, it exhibits a hexagonal array of magnetic flux tubes, and, due to the chiral anomaly, a spatially oscillating baryon number of the same crystalline structure. [ABSTRACT FROM AUTHOR]

We discuss electroweak baryogenesis in aligned two Higgs doublet models. It is known that in this model the severe constraint from the experimental results for the electron electric dipole moment can be avoided by destructive interference among CP-violating effects in the Higgs sector. In our previous work, we showed that the observed baryon number in the Universe can be explained without contradicting current available data in a specific scenario in the same model. We here first discuss details of the evaluation of baryon number based on the WKB method taking into account all order of the wall velocity. We then investigate parameter spaces which are allowed under the current available data from collider, flavor and electric dipole moment experiments simultaneously. We find several benchmark scenarios which can explain baryon asymmetry of the Universe. We also discuss how we can test these benchmark scenarios at future collider experiments, various flavor experiments and gravitational wave observations. [ABSTRACT FROM AUTHOR]

Realistic models based on the renormalizable grand unified theories have varieties of scalars, many of which are capable of mediating baryon (B) and lepton (L) number non-conserving processes. We identify all such scalar fields residing in 10, 126 ¯ and 120 dimensional irreducible representations of SO(10) which can induce baryon and lepton number violating interactions through the leading order d = 6 and d = 7 operators. Explicitly computing their couplings with the standard model fermions, we derive the effective operators including the possibility of mixing between the scalars stemming from a given representation. We find that such interactions at d = 6 are mediated by only three sets of scalars: T(3, 1, −1/3), T (3, 1, −4/3) and T (3, 3, −1/3) and their conjugates. In the models with 10 and 126 ¯ , only the first has appropriate couplings to mediate the proton decay. While T and T can induce baryon number violating interactions when 120 is present, T does not contribute to the proton decay at tree level because of its flavour antisymmetric coupling. Three additional colour triplets and their conjugates can mediate nucleon decay via d = 7 operators which violate also the B − L. We give general expressions for partial widths of proton in terms of the fundamental Yukawa couplings and use these results to explicitly compute the proton lifetime and branching ratios for the minimal non-supersymmetric SO(10) model based on 10 and 126 ¯ Higgs. We find that the proton preferably decays into ν ¯ K+ or μ+K0 and list several distinct features of scalar mediated proton decay. If the latter dominates over the gauge mediated contributions, the proton decay spectrum provides a direct probe to the flavour structure of the underlying grand unified theory. [ABSTRACT FROM AUTHOR]

We investigate an economical explanation for the (g − 2)μ anomaly with a neutral vector boson from a spontaneously broken U(1)X gauge symmetry. The Standard Model fermion content is minimally extended by 3 right-handed neutrinos. Using a battery of complementary constraints, we perform a thorough investigation of the renormalizable, quark flavor-universal, vector-like U(1)X models, allowing for arbitrary kinetic mixing. Out of 419 models with integer charges not greater than ten, only 7 models are viable solutions, describing a narrow region in model space. These are either Lμ− Lτ or models with a ratio of electron to baryon number close to −2. The key complementary constraints are from the searches for nonstandard neutrino interactions. Furthermore, we comment on the severe challenges to chiral U(1)X solutions and show the severe constraints on a particularly promising such candidate. [ABSTRACT FROM AUTHOR]

It is clear that matter is dominant in the Universe compared to antimatter. We call this problem baryon asymmetry. The baryon asymmetry is experimentally determined by both cosmic microwave background and big bang nucleosynthesis measurements. To resolve the baryon number asymmetry of the Universe as well as neutrino oscillations, we study a radiative seesaw model in a modular A4 symmetry. Degenerate heavy Majorana neutrino masses can be naturally realized in an appropriate assignments under modular A4 with large imaginary part of modulus τ, and it can induce measured baryon number via resonant leptogenesis that is valid in around TeV scale energy theory. We also find that the dominant contribution to the CP asymmetry arises from Re[τ] through our numerical analysis satisfying the neutrino oscillation data. [ABSTRACT FROM AUTHOR]

We investigate an economical explanation for the (g − 2)μ anomaly with a neutral vector boson from a spontaneously broken U(1)X gauge symmetry. The Standard Model fermion content is minimally extended by 3 right-handed neutrinos. Using a battery of complementary constraints, we perform a thorough investigation of the renormalizable, quark flavor-universal, vector-like U(1)X models, allowing for arbitrary kinetic mixing. Out of 419 models with integer charges not greater than ten, only 7 models are viable solutions, describing a narrow region in model space. These are either Lμ− Lτ or models with a ratio of electron to baryon number close to −2. The key complementary constraints are from the searches for nonstandard neutrino interactions. Furthermore, we comment on the severe challenges to chiral U(1)X solutions and show the severe constraints on a particularly promising such candidate. [ABSTRACT FROM AUTHOR]

We report the first measurements of cumulants, up to 4 t h order, of deuteron number distributions and proton-deuteron correlations in Au+Au collisions recorded by the STAR experiment in phase-I of Beam Energy Scan (BES) program at the Relativistic Heavy Ion Collider. Deuteron cumulants, their ratios, and proton-deuteron mixed cumulants are presented for different collision centralities covering a range of center-of-mass energy per nucleon pair s NN = 7.7 to 200 GeV. It is found that the cumulant ratios at lower collision energies favor a canonical ensemble over a grand canonical ensemble in thermal models. An anti-correlation between proton and deuteron multiplicity is observed across all collision energies and centralities, consistent with the expectation from global baryon number conservation. The UrQMD model coupled with a phase-space coalescence mechanism qualitatively reproduces the collision-energy dependence of cumulant ratios and proton-deuteron correlations. [ABSTRACT FROM AUTHOR]

Dyonium induced fermion number violation is studied in a S U (2) L × U (1) Y gauge theory with a doublet Higgs field. Dyonium is a generalization of Nambu's monopolium, having finite sized pair of dyon and anti-dyon, connected with a thin string under the linear plus Coulomb force.1 This is a follow-up of the author's paper on monopolium induced neutrino mass (including the lepton and baryon number violations), studied with a SO(10) Grand Unified model in 1983. To fulfill the requirement from the chiral anomaly or its index theorem, an electric field should be excited in parallel to the dipole magnetic field. This crucial dynamical problem, not fully answered then, has been solved, by considering not monopolium but dyonium. The fermionic zero modes in the dyonium background fields are necessary in evaluating the transition rate of the fermion number violation processes. Their Dirac equation can be reduced to a single component partial differential equation, similar to the renormalization group equation, which may be useful to estimate the reaction rates. [ABSTRACT FROM AUTHOR]

We show that the Linear Sigma Model with quarks produces an effective description of the QCD phase diagram and of the system's equilibrium distribution properties that deviate from those of the Hadron Resonance Gas Model. The deviation is due to the inclusion of plasma screening properties, encoded in the contribution of the ring diagrams and thus to the introduction of a key feature of plasmas near phase transitions, namely, long-range correlations. After fixing the model parameters using input from LQCD for the crossover transition at vanishing chemical potential, we study the location of the Critical End Point in the effective QCD phase diagram. We use the model to study baryon number fluctuations and show that in heavy-ion collisions, the CEP can be located for collision energies s NN ∼ 2 GeV, namely, in the lowest NICA or within the HADES energy domain. [ABSTRACT FROM AUTHOR]

Even though lots of Λ -hypernuclei have been found and measured, multi-strangeness hypernuclei consisting of Ω are not yet discovered. The studies of multi-strangeness hypernuclei help us further understand the interaction between hyperons and nucleons. Recently the Ω N and Ω Ω interactions as well as binding energies were calculated by the HAL-QCD's lattice Quantum Chromo-Dynamics (LQCD) simulations and production rates of Ω -dibaryon in Au + Au collisions at RHIC and Pb + Pb collisions at LHC energies were estimated by a coalescence model. The present work discusses the production of more exotic triple-baryons including Ω , namely Ω N N and Ω Ω N as well as their decay channels. A variation method is used in calculations of bound states and binding energy of Ω N N and Ω Ω N with the potentials from the HAL-QCD's results. The productions of Ω N N and Ω Ω N are predicted by using a blast-wave model plus coalescence model in ultra-relativistic heavy-ion collisions at s NN = 200 GeV and 2.76 TeV. Furthermore, plots for baryon number dependent yields of different baryons (N and Ω ), their dibaryons and hypernuclei are made and the production rate of a more exotic tetra-baryon ( Ω Ω N N ) is extrapolated. [ABSTRACT FROM AUTHOR]