Search

Cosmic voids identified in the spatial distribution of galaxies provide complementary information to two-point statistics. In particular, constraints on the neutrino mass sum, ∑ m ν , promise to benefit from the inclusion of void statistics. We perform inference on the CMASS Northern Galactic Cap sample of the third-generation Sloan Digital Sky Survey/Baryon Oscillation Spectroscopic Survey (BOSS) with the aim of constraining ∑ m ν . We utilize the void size function, the void–galaxy cross power spectrum, and the galaxy auto power spectrum. To extract constraints from these summary statistics we use a simulation-based approach, specifically implicit likelihood inference. We populate approximate gravity-only, particle-neutrino cosmological simulations with an expressive halo occupation distribution model. With a conservative scale cut of k max = 0.15 h Mpc − 1 and a Planck-inspired Lambda cold dark matter prior, we find upper bounds on ∑ m ν of 0.43 and 0.35 eV from the galaxy auto power spectrum and the full data vector, respectively (95% credible interval). Relaxing the scale cut to k max = 0.2 h Mpc − 1 , we find 0.28 and 0.32 eV. Generally, void statistics appear to add modest but nonzero information beyond the auto power spectrum. We also substantiate the usual assumption that the void size function is Poisson distributed. [ABSTRACT FROM AUTHOR]

Sterile neutrinos in the keV mass range present a viable candidate for dark matter. They can be detected through single β -decay, where they cause small spectral distortions. The Karlsruhe Tritium Neutrino (KATRIN) experiment aims to search for keV-scale sterile neutrinos with high sensitivity. To achieve this, the KATRIN beamline will be equipped with a novel multi-pixel silicon drift detector focal plane array named TRISTAN. In this study, we present the performance of a TRISTAN detector module, a component of the eventual 9-module system. Our investigation encompasses spectroscopic aspects such as noise performance, energy resolution, linearity, and stability. [ABSTRACT FROM AUTHOR]

Nonlinear gravitational evolution induces strong nonlinearities in the observed cosmological density fields, leading to positive off-diagonal correlations in the power spectrum covariance. This has caused the information saturation in the power spectrum, e.g., the neutrino mass constraints from the nonlinear power spectra are lower than their linear counterparts by a factor of ∼2 at z = 0. In this paper, we explore how nonlinear reconstruction methods improve the cosmological information from nonlinear cosmic fields. By applying nonlinear reconstruction to cold dark matter fields from the Quijote simulations, we find that nonlinear reconstruction can improve the constraints on cosmological parameters significantly, nearly reaching the linear theory limit. For neutrino mass, the result is only 12% lower than the linear power spectrum, i.e., the theoretical best result. This makes nonlinear reconstruction an efficient and useful method to extract neutrino information from current and upcoming galaxy surveys. [ABSTRACT FROM AUTHOR]

We endeavour to constrain the neutrino mass matrix on the phenomenological ground and procure model-independent textures by emphasizing on the simple linear relationships among the mass matrix elements. These simple textures predict the two Majorana phases. In this regard, two types of parametrization of neutrino mass matrix: general and exponential are employed. We obtain fifty-three predictive neutrino mass matrix textures, out of which twenty-eight are associated with the general parametrization, and the rest belong to the exponential one. Apart from Type-A/P textures, the rest deal with the prediction of a few other oscillation parameters as well. We try to realize the proposed textures in the light of A 4, Δ(27) and T 7 symmetry groups. [ABSTRACT FROM AUTHOR]

Measuring the sum of the three active neutrino masses, M ν , is one of the most important challenges in modern cosmology. Massive neutrinos imprint characteristic signatures on several cosmological observables, in particular, on the large-scale structure of the universe. In order to maximize the information that can be retrieved from galaxy surveys, accurate theoretical predictions in the nonlinear regime are needed. Currently, one way to achieve those predictions is by running cosmological numerical simulations. Unfortunately, producing those simulations requires high computational resources—several hundred to thousand core hours for each neutrino mass case. In this work, we propose a new method, based on a deep-learning network (D3M), to quickly generate simulations with massive neutrinos from standard ΛCDM simulations without neutrinos. We computed multiple relevant statistical measures of deep-learning generated simulations and conclude that our approach is an accurate alternative to the traditional N -body techniques. In particular the power spectrum is within ≃6% down to nonlinear scales k = 0.7 h Mpc−1. Finally, our method allows us to generate massive neutrino simulations 10,000 times faster than the traditional methods. [ABSTRACT FROM AUTHOR]

The location of Îł -ray-emitting region in blazars has been an open issue for several decades and is still being debated. We use the Paliya et al. sample of 619 Îł -ray-loud flat-spectrum radio quasars with available spectral energy distributions and employ a seed photon factor approach to locate the Îł -ray production region. This method efficiently sets up a relation between the peak frequencies and luminosities for the synchrotron emission and inverse Compton scattering, together with a combination of the energy density and characteristic energy for the external seed photon field, namely, U 0 / ϵ 0 , an indicative factor of seed photons in units of Gauss. By comparing it with canonical values of the broad-line region (BLR) and molecular dusty torus (DT), we principally ascertain that the GeV emission originated far beyond the BLR and close to the DTâ€"farther out at parsec scales from the central black hole, which supports a far-site scenario for Îł -ray blazars. We probe the idea that inverse Compton scattering of infrared seed photons is happening in the Thomson regime. This approach and our findings are based on the validity of the external Compton model, which is applicable in understanding the GeV emission mechanism in FSRQs. However, the completeness of this framework has been challenged by reports of neutrino emission from blazars. Thus, we also shed new light on the neutrino production region by using our derived results because blazars are promising neutrino emitters. [ABSTRACT FROM AUTHOR]

We construct a B âˆ' L model with A 4 Ă— Z 3 Ă— Z 4 flavor symmetry that accounts for the recent 3 + 1 active-sterile neutrino data. The tiny neutrino mass and the mass hierarchy are obtained by the type-I seesaw mechanism. The hierarchy of the lepton masses is satisfied by a factor of v H v l Λ 2 ∼ 1 0 âˆ' 4 G e V of the electron mass compared to the muon and tau masses of the order of v H v l Λ ∼ 1 0 âˆ' 1 G e V. The 3 + 1 active-sterile neutrino mixings are predicted to be 0.015 â©˝ | U 14|2 â©˝ 0.045, 0.004 â©˝ | U 24|2 â©˝ 0.012 and 0.004 â©˝ | U 34|2 â©˝ 0.014 for normal hierarchy while 0.020 â©˝ | U 14|2 â©˝ 0.045, 0.008 â©˝ | U 24|2 â©˝ 0.018 and 0.008 â©˝ | U 34|2 â©˝ 0.022 for inverted hierarchy. Sterile neutrino masses are predicted to be 0.7 ≲ m s  (eV) ≲ 3.16 for normal hierarchy and 2.6 ≲ m s  (eV) ≲ 7.1 for inverted hierarchy. For three neutrino scheme the model predicts 0.3401 â©˝ sin2  θ 12 â©˝ 0.3415, 0.460 â©˝ sin2  θ 23 â©˝ 0.540, âˆ'0.60 â©˝ sin  δ CP â©˝ âˆ'0.20 for normal hierarchy and 0.3402 â©˝ sin2  θ 12 â©˝ 0.3416, 0.434 â©˝ sin2  θ 23 â©˝ 0.610, âˆ'0.95 â©˝ sin  δ CP â©˝ âˆ' 0.60 for inverted hierarchy. [ABSTRACT FROM AUTHOR]

Recently there have been reports of finding a lower bound on the neutrino mass parameter (ÎŁ m ν ) when using the Atacama Cosmology Telescope (ACT) and SPTpol data; however, these bounds on the ÎŁ m ν are still weaker for most cases around the 1 σ level. In this context, here in this work, we study the consequences of using an enlarged four parameter dynamical dark energy equation of state on the neutrino mass parameter as well as on the Hubble and S8 tensions. The four parameter dark energy equation of state incorporates a generic nonlinear monotonic evolution of the dark energy equation of state, where the four parameters are the early and the present value of the equation of state, the transition scale factor, and the sharpness of the transition. We report that with lensing-marginalized Planck + BAO + Pantheon and prior on absolute magnitude M B , and KIDS/Viking S 8 prior, the model favors a nonzero value for the neutrino mass parameter at most at the 1 σ level ( ÎŁ m ν = 0.1847 âˆ' 0.165 + 0.0698 eV). In this case this model also brings down the Hubble tension to a 2.5 σ level and the S8 tension to a ∼1.5 σ level. This model also provides tighter constraints on the value of the dark energy equation of state at present epoch w 0 ( w 0 = âˆ' 0.9901 âˆ' 0.0766 + 0.0561 ) in comparison to the Chevalier-Polarski and Linder-like parameterization. [ABSTRACT FROM AUTHOR]

We present a complementary methodology to constrain the total neutrino mass, âˆ' m ν , based on the diffusion coefficient of the splashback mass function of dark matter halos. Analyzing the snapshot data from the Massive Neutrino Simulations, we numerically obtain the number densities of distinct halos identified via the SPARTA code as a function of their splashback masses at various redshifts for two different cases of âˆ' m ν = 0.0 and 0.1 eV. Then, we fit the numerical results to the recently developed analytic formula characterized by the diffusion coefficient that quantifies the degree of ambiguity in the identification of the splashback boundaries. Our analysis confirms that the analytic formula works excellently even in the presence of neutrinos and that the decrement of its diffusion coefficient with redshift is well described by a linear fit, B (z âˆ' z c ), in the redshift range of 0.2 ≤ z ≤ 2. It turns out that the massive neutrino case yields a significantly lower value of B and a substantially higher value of z c than the massless neutrino case, which indicates that the higher the masses that neutrinos have, the more severely the splashback boundaries become disturbed by the surroundings. Given our result, we conclude that the total neutrino mass can in principle be constrained by measuring how rapidly the diffusion coefficient of the splashback mass function diminishes with redshifts at z ≥ 0.2. We also discuss the anomalous behavior of the diffusion coefficient found at lower redshifts for both of the âˆ' m ν cases, and ascribe it to the fundamental limitation of the SPARTA code at z ≤ 0.13. [ABSTRACT FROM AUTHOR]

The scotogenic model is a well motivated scenario that provides both an explanation for neutrino masses and for dark matter (DM). We focus on a real scalar DM candidate in this model, produced through standard thermal freeze-out. We analyze the parameter space of the model compatible with the observed DM relic abundance, direct and indirect detection searches, limits from lepton flavour violating decays and constraints from the neutrino sector. As the mass differences of the DM with the neutral and charged states are found to be small, the new scalars and fermions of the theory will have macroscopic lifetimes, and could thus be potentially detected with long-lived particle signatures at colliders. We find regions in the parameter space to beâ€"partially or fullyâ€"consistent with the DM relic abundance, and the prediction of a long-lived charged scalar or lightest neutral fermion in the scotogenic scenario, for DM masses below 500 GeV. We discuss on the collider phenomenology in some detail. [ABSTRACT FROM AUTHOR]

Cyclotron radiation emission spectroscopy (CRES) is a modern approach for determining charged particle energies via high-precision frequency measurements of the emitted cyclotron radiation. For CRES experiments with gas within the fiducial volume, signal and noise dynamics can be modelled by a hidden Markov model. We introduce a novel application of the Viterbi algorithm in order to derive informational limits on the optimal detection of cyclotron radiation signals in this class of gas-filled CRES experiments, thereby providing concrete limits from which future reconstruction algorithms, as well as detector designs, can be constrained. The validity of the resultant decision rules is confirmed using both Monte Carlo and Project 8 data. [ABSTRACT FROM AUTHOR]

We make an investigation of modular Î" 5 ′ ≃ A 5 ′ group in inverse seesaw framework. Modular symmetry is advantageous because it reduces the usage of extra scalar fields significantly. Moreover, the Yukawa couplings are expressed in terms of Dedekind eta functions, which also have a q expansion form, generally utilized to achieve numerical simplicity. Our proposed model includes six heavy fermion superfields i.e., N R i , S L i and a weighton. The study of neutrino phenomenology becomes simplified and effective by the usage of A 5 ′ modular symmetry, which provides us a well defined mass structure for the lepton sector. Here, we observe that all the neutrino oscillation parameters, as well as the effective electron neutrino mass in neutrinoless double beta decay can be successfully accommodated in this model. We also briefly discuss the lepton flavor violating decays â„" i â†' â„" j Îł, the collider bound on Z ′ mass and comment on non-unitarity of lepton mixing matrix. [ABSTRACT FROM AUTHOR]

We discuss the phenomenology of type-II seesaw by extending the standard model with additional Higgs doublets, scalar triplets as well as a scalar singlet invoked with discrete flavor symmetry Δ(27), for the explanation of non-zero neutrino masses and mixing, matter–antimatter asymmetry, and lepton flavor violation (LFV). The light neutrino masses can be obtained via type-II seesaw mechanism by transforming scalar triplets as 3 and scalar doublets as various singlet representations like 1 1 , 1 2 , 1 3 along with scalar singlet as 1 1 under Δ(27) symmetry. With the implementation of this discrete flavor symmetry Δ(27), we get simpler structure for light neutrino mass matrix, which helps in analyzing neutrino phenomenology analytically as well as numerically. We further demonstrate the detailed numerical analysis by scanning the input model parameters in agreement with neutrino oscillation data like non-zero reactor mixing angle (θ 13), CP-violating phase (δ CP), the sum of the light neutrino masses, two mass squared differences, and its implication to neutrino-less double beta decay. The model also explains the matter–antimatter asymmetry of the Universe through resonant leptogenesis with the decay of TeV scale scalar triplets and variation of CP-asymmetry with input model parameters. Finally, we comment on the implication to LFV decays like μ → eγ, μ → 3 e processes via the mediation of these TeV scale scalar triplets. We have studied collider physics briefly. [ABSTRACT FROM AUTHOR]

We quantify the information content of the nonlinear matter power spectrum, the halo mass function, and the void size function, using the Quijote N-body simulations. We find that these three statistics exhibit very different degeneracies among the cosmological parameters, and thus the combination of all three probes enables the breaking of degeneracies, in turn yielding remarkably tight constraints. We perform a Fisher analysis using the full covariance matrix, including all auto- and cross correlations, finding that this increases the information content for neutrino mass compared to a correlation-free analysis. The multiplicative improvement of the constraints on the cosmological parameters obtained by combining all three probes compared to using the power spectrum alone are: 137, 5, 8, 20, 10, and 43, for Ωm, Ωb, h, ns, σ8, and Mν, respectively. The marginalized error on the sum of the neutrino masses is σ(Mν) = 0.018 eV for a cosmological volume of , using , and without cosmic microwave background (CMB) priors. We note that this error is an underestimate insomuch as we do not consider super-sample covariance, baryonic effects, and realistic survey noises and systematics. On the other hand, it is an overestimate insomuch as our cuts and binning are suboptimal due to restrictions imposed by the simulation resolution. Given upcoming galaxy surveys will observe volumes spanning , this presents a promising new avenue to measure neutrino mass without being restricted by the need for accurate knowledge of the optical depth, which is required for CMB-based measurements. Furthermore, the improved constraints on other cosmological parameters, notably Ωm, may also be competitive with CMB-based measurements. [ABSTRACT FROM AUTHOR]

We propose a non-universal U(1)X gauge extension to the standard model (SM) and an additional Peccei–Quinn (PQ) global symmetry to study the mass hierarchy and strong CP problem. The scheme allows us to distinguish among fermion families and to generate the fermionic mass spectrum of particles of the SM. The symmetry breaking is performed by two scalar Higgs doublets and two scalar Higgs singlets, where one of these has the axion which turns out to be a candidate for cold dark matter. The exotic sector is composed by one up-like T and two down-like J1,2 heavy quarks, two heavy charged leptons , one additional right-handed neutrino per family , and an invisible axion a. In addition, the large energy scale associated to the breaking of the PQ-symmetry gives masses to the right-handed neutrinos in such a way that the active neutrinos acquire eV-mass values due to the see-saw mechanism. On the other hand, from the non-linear effective Lagrangian, the flavour changing of the down quarks and charged leptons with the axion are considered. [ABSTRACT FROM AUTHOR]

We investigate the phenomenology of singlet scalar dark matter (DM) in a simple U(1)B−L gauge extension of the standard model, made anomaly-free with four exotic fermions. The enriched scalar sector and the new gauge boson Z′, associated with U(1) gauge extension, connect the dark sector to the visible sector. We compute relic density, consistent with Planck limit and a Z′ mediated DM-nucleon cross section, compatible with PandaX bound. The mass of Z′ and the corresponding gauge coupling are constrained from LEP-II and LHC dilepton searches. We also briefly scrutinize the tree-level neutrino mass with a dimension five operator. Furthermore, resonant leptogenesis phenomena is discussed with TeV-scale exotic fermions to produce the observed baryon asymmetry of the Universe. Further, we briefly explain the impact of flavor in leptogenesis and we also project the combined constraints on Yukawa, consistent with oscillation data and observed baryon asymmetry. Additionally, we restrict the new gauge parameters by using the existing data on branching ratios of rare B(τ) decay modes. We see that the constraints from the dark sector are much more stringent from the flavor sector. [ABSTRACT FROM AUTHOR]

The recent measurements of lepton flavor universality (LFU) violating observables in semileptonic and b → sℓ+ℓ− transitions by various experiments hint towards the possible role of new physics (NP) in and b → sμ+μ− decay channels. This in turn suggests that the same class of NP as appeared in , might also show up in other tree level processes involving transition. In this paper, we study the implications of the vector leptoquark (LQ) U1(3, 1, 2/3), which is one of the few scenarios that can simultaneously explain all the observed LFU violating signals, on the semileptonic decays and. In particular, we pay our attention to the branching fractions, lepton flavor non-universality (LNU) observables, forward–backward asymmetry and the polarization asymmetry parameters of these decay modes. We find that substantial deviations in the branching fractions as well as LNU observables could be possible due to the additional contributions from U1 LQ, which can be probed by the currently running experiments LHCb and Belle-II. [ABSTRACT FROM AUTHOR]

We classify all possible texture zeros in a light neutrino mass matrix in a diagonal charged lepton basis by considering the Dirac nature of light neutrinos. For the Hermitian nature of neutrino mass matrix, the number of possible texture zeros remain the same as Majorana texture zeros, but with less free parameters due to the absence of additional Majorana CP phases. Relaxing the Hermitian nature of the neutrino mass matrix leads to many more possibilities and freedom due to additional CP phases, mixing angles not constrained by neutrino data. While we find only a very few of the one-zero and two-zero textures in the Hermitian case to be allowed, in the non-Hermitian case some textures even with four zeros are allowed. While most of the one-zero, two-zero and three-zero textures in this case are allowed, four-zero textures are tightly constrained with only six allowed out of 126 possibilities. The allowed textures also give interesting correlations between light neutrino parameters with sharp distinctions between normal and inverted mass ordering. Many of these allowed textures also saturate the Planck 2018 upper bound on the sum of absolute neutrino masses. [ABSTRACT FROM AUTHOR]

Given its briefness and predictability, the minimal seesaw—a simplified version of the canonical seesaw mechanism with only two right-handed neutrino fields—has been studied in depth and from many perspectives, and now it is being pushed close to a position of directly facing experimental tests. This article is intended to provide an up-to-date review of various phenomenological aspects of the minimal seesaw and its associated leptogenesis mechanism in neutrino physics and cosmology. Our focus is on possible flavor structures of such benchmark seesaw and leptogenesis scenarios and confronting their predictions with current neutrino oscillation data and cosmological observations. In this connection particular attention will be paid to the topics of lepton number violation, lepton flavor violation, discrete flavor symmetries, CP violation and antimatter of the Universe. [ABSTRACT FROM AUTHOR]

The hypothesis of the decay of neutrino mass eigenstates leads to a substantial modification of the appearance and disappearance probabilities of flavor eigenstates. We investigate the impact on the standard oscillation scenario caused by the decay of the heaviest mass eigenstate ν3 (with a mass m3 and a mean life τ3) to a sterile state in deep underground neutrino experiment. We find that the lower bound of 5.1 × 10−11 s eV−1 at 90% confidence level on the decay parameter τ3/m3 can be set if the neutral current data are included in the analysis, thus providing the best long-baseline expected limit so far. We also show that the ντ appearance channel would give only a negligible contribution to the decay parameter constraints. Our numerical results are corroborated by analytical formulae for the appearance and disappearance probabilities in vacuum (which is a useful approximation for the study of the invisible decay model) that we have developed up to the second order in the solar mass splitting and to all orders in the decay factor t/τ3. [ABSTRACT FROM AUTHOR]

A failed core-collapse supernova from a nonrotating progenitor can eject mass due to a weakening of gravity associated with neutrino emission from the protoneutron star. This mechanism yields observable transients and sets an upper limit on the mass of the black hole (BH) remnant. Previous global simulations of this mechanism have included neutrino losses parametrically, however, with direct implications for the ejecta mass and energy. Here we evolve the inner supernova core with a spherically symmetric, general-relativistic neutrino radiation-hydrodynamic code until BH formation. We then use the result in a Newtonian code that follows the response of the outer layers of the star to the change in gravity and resolves the surface pressure scale height. We find that the dense-matter equation of state (EOS) can introduce a factor of ∼2 variation in gravitational mass lost to neutrinos, with a stiff EOS matching previous parametric results and a soft EOS yielding lower ejecta masses and energies by a factor of several. This difference is caused primarily by the longer time to BH formation in stiffer EOSs. With a soft EOS, our red and yellow supergiant progenitors fail to unbind mass if hydrogen recombination energy is not included. Using a linear ramp in time for mass-energy lost to neutrinos (with suitable parameters) yields a stellar response within ∼10% of that obtained using the detailed history of neutrino losses. Our results imply quantitative but not qualitative modifications to previous predictions for shock breakout, plateau emission, and final BH masses from these events. [ABSTRACT FROM AUTHOR]

Parametrization of the neutrino mass matrix in terms of well-known measured quantities is an attractive way to obtain a phenomenologically viable form. We propose a model of neutrino mass matrix based on type-II seesaw mechanism adhering the concept of badly broken symmetry. Two of the mixing angles are coming out as θ23 ∼ 46.08°, θ13 ∼ 8.69°. However, to accommodate the other oscillation parameters, we further add an extra doublet and the neutrino masses are generated through the Zee mechanism at the one loop level, and the modified model can admit all the extant data for a suitable choice of model parameters. [ABSTRACT FROM AUTHOR]

The TBM neutrino mass matrix is invariant under the TM1, TM2, and μ − τ exchange symmetry. The prediction of vanishing θ13 by TBM is due to its invariance under μ − τ exchange symmetry. We can construct neutrino mass textures where TBM mass matrix is the main contributing matrix and a μ − τ symmetry breaking term is added as an additional contribution. The overall matrix will be invariant under either TM1 or TM2 symmetry only. We present eight such textures which are invariant under either TM1 or TM2 symmetry but are not invariant under the μ − τ exchange symmetry. These textures give definite predictions on the values of mβ, mββ, CP violating phase δ, and the octant of the mixing angle θ23. [ABSTRACT FROM AUTHOR]

In loop quantum gravity (LQG) the quantisation of general relativity leads to precise predictions for the eigenvalues of geometrical observables like volume and area, up to the value of the only free parameter of the theory, the Barbero–Immirzi (BI) parameter. With the help of the eigenvalues equation for the area operator, LQG successfully derives the Bekenstein–Hawking entropy of large black holes with isolated horizons, fixing at this limit the BI parameter as γ ≈ 0.274. In the present paper we show some evidence that a black hole with angular momentum ℏ and Planck mass is an eigenstate of the area operator provided that. As the black hole is extremal, there is no Hawking radiation and the horizon is isolated. We also suggest that such a black hole can be formed in the head-on scattering of two parallel standard model neutrinos in the mass state m2 (assuming m1 = 0). Furthermore, we use the obtained BI parameter to numerically compute the entropy of isolated horizons with areas ranging up to , by counting the number of micro-states associated to a given area. The resulting entropy has a leading term , in agreement to the Bekenstein–Hawking entropy. As the identification of the above eigenstate rests on the matching between classical areas and quantum area eigenvalues, we also present, on the basis of an effective quantum model for the Schwarzschild black hole recently proposed by Ashtekar, Olmedo and Singh, an expression for the quantum corrected area of isolated horizons, valid for any black hole mass. Quantum corrections are shown to be negligible for a Planck mass black hole, of order 10−3 relative to the classical area. [ABSTRACT FROM AUTHOR]

In this work, we study an extension of the standard model (SM) based on the gauge symmetry SU(3)C × SU(2)L × U(1)Y′ × U(1)R where only the right-handed fermions have nonzero U(1)R charge and the weak hypercharge of the SM is identified as a combination of the U(1)Y′ and U(1)R charges. The gauge charge assignment of the fields is constrained by the conditions of the anomaly cancellation and the gauge invariance of the Yukawa couplings. The light neutrino masses are generated via the type-I seesaw mechanism where the Majorana masses of the right-handed neutrinos are related to the U(1)Y′ × U(1)R symmetry breaking scale. Then, we discuss the constraints on the free parameters of the model from various current experiments, such as the precision measurement of the total Z width, ρ parameter, atomic parity violation of cesium, LEP and LHC bounds. In addition, we investigate the potential of probing for the signal of the new neutral gauge boson based on the forward–backward asymmetry for the process e+e− → μ+μ− which is the most sensitive mode at the ILC. [ABSTRACT FROM AUTHOR]

We show that future observations of binary neutron star systems with electromagnetic counterparts together with the traditional probes of low- and high-redshift Type Ia supernovae (SNe Ia) can help resolve the Hubble tension. The luminosity distance inferred from these probes and its scatter depend on the underlying cosmology. By using the gravitational lensing of light or gravitational waves emitted by, and peculiar motion of, these systems we derive constraints on the sum of neutrino masses, the equation of state of dark energy parameterized in the form , along with the Hubble constant and cold dark matter density in the universe. We show that even after marginalizing over poorly constrained physical quantities, such as the sum of neutrino masses and the nature of dark energy, low-redshift gravitational-wave observations, in combination with SNe Ia, have the potential to rule out new physics as the underlying cause of the Hubble tension at ≳5.5σ. [ABSTRACT FROM AUTHOR]

We present the results of cosmological simulations of large-scale structure formation with massive neutrinos. The phase-space distribution of the cosmic relic neutrinos is followed, for the first time, by directly integrating the six-dimensional Vlasov–Poisson equations. Our novel approach allows us to represent free streaming and clustering of neutrinos, and their gravitational interaction with cold dark matter accurately. We thus obtain solutions for the collisionless dynamics independent of conventional N-body methods. We perform a suite of hybrid N-body/Vlasov simulations with varying the neutrino mass, and systematically examine the dynamical effects of massive neutrinos on large-scale structure formation. Our simulations show characteristic large-scale clustering of the neutrinos and their coherent streaming motions relative to dark matter. The effective local neutrino "temperature" around massive galaxy clusters varies by several percent with respect to the cosmic mean; the neutrinos in clusters can be hotter or colder depending on the neutrino mass. We study a number of statistics of the large-scale structure and of dark matter halos in comparison with those obtained by N-body simulations and/or by perturbation theory. Our simulations mark an important milestone in numerical cosmology, and pave a new way to study cosmic structure formation with massive neutrinos. [ABSTRACT FROM AUTHOR]

We study the possibility of texture zeros in Majorana light neutrino mass matrix in the light of dark large mixing angle (DLMA) solution to solar neutrino problem where solar mixing angle (sin2θ12 ≃ 0.7) lies in the second octant instead of first octant in standard large mixing angle (LMA) scenario (sin2θ12 ≃ 0.3). In three neutrino scenario, we find that LMA and DLMA solutions lead to different set of allowed and disallowed textures with one and two zeros. While being consistent with existing bounds from neutrino oscillation data, neutrinoless double beta decay and cosmology these allowed textures also lead to interesting correlations among light neutrino parameters which can distinguish LMA from DLMA solution. We also check the implications for texture zeros in 3 + 1 neutrino scenario using both LMA and DLMA solutions. While LMA and DLMA solutions do not play decisive role in ruling out texture zeros in this case, they do give rise to distinct predictions and correlations between light neutrino parameters. [ABSTRACT FROM AUTHOR]

We report on the core-collapse supernova simulation we conducted for a 11.2M⊙ progenitor model in three-dimensional space up to 20 ms after bounce, using a radiation-hydrodynamics code with full Boltzmann neutrino transport. We solve the six-dimensional Boltzmann equations for three neutrino species and the three-dimensional compressible Euler equations with Furusawa and Togashi's nuclear equation of state. We focus on the prompt convection at ∼10 ms after bounce and investigate how neutrinos are transported in the convective matter. We apply a new analysis based on the eigenvalues and eigenvectors of the Eddington tensor and make a comparison between the Boltzmann transport results and the M1 closure approximation in the transition regime between the optically thick and thin limits. We visualize the eigenvalues and eigenvectors using an ellipsoid, in which each principal axis is parallel to one of the eigenvectors and has a length proportional to the corresponding eigenvalue. This approach enables us to understand the difference between the Eddington tensor derived directly from the Boltzmann simulation and the one given by the M1 prescription from a new perspective. We find that the longest principal axis of the ellipsoid is almost always nearly parallel to the energy flux in the M1 closure approximation, whereas in the Boltzmann simulation it becomes perpendicular in some transition regions, where the mean free path is ∼0.1 times the radius. In three spatial dimensions, the convective motions make it difficult to predict where this happens and to possibly improve the closure relation there. [ABSTRACT FROM AUTHOR]

In this work, we propose new five texture zeros for the mass matrices in the lepton sector in order to predict neutrino masses. In our approach, we extend beyond the standard model (SM) by assuming Dirac masses for the neutrinos, a feature which allows us to make a theoretical prediction for the lightest neutrino mass in the normal ordering. The textures that were analyzed have enough free parameters to adjust the VPMNS mixing matrix including the CP-violating phase, the neutrino mass squared differences , and the three charged lepton masses. In order to obtain reliable results, we used two different procedures that are based on the weak basis transformation, a well known technique to analyze textures and their implications for flavor physics. The first method was based on a least-squares analysis to theoretically fit the lepton masses and the mixing parameters to their corresponding experimental values; for this case, the best fit obtained for the lightest neutrino mass was eV. The second approach was algebraic, resulting in a lightest neutrino mass consistent with the experimental values and the restrictions arising from the five texture zeros of the mass matrices, and the lightest neutrino mass obtained was (3.5 ± 0.9) × 10−3 eV. [ABSTRACT FROM AUTHOR]

Using the Boltzmann-radiation-hydrodynamics code, which solves the Boltzmann equation for neutrino transport, we present the results of the simulations with the nuclear equations of state (EOSs) of Lattimer and Swesty (LS) and Furusawa and Shen (FS). We extend the simulation time of the LS model and conduct thorough investigations, though our previous paper briefly reported some of the results. Only the LS model shows the shock revival. This seems to originate from the nuclear composition: the different nuclear composition results in the different energy loss by photodissociation and hence the different strength of the prompt convection and the later neutrino-driven convection. The protoneutron star seen in the FS model is more compact than that in the LS model because the existence of multinuclear species softens the EOS. For the behavior of neutrinos, we examined the flux and the Eddington tensor of neutrinos. In the optically thick region, the diffusion of neutrinos and the dragging by the motion of matter determine the flux. In the optically thin region, the free-streaming determines it. The Eddington tensor is compared with that obtained from the M1-closure relation. The M1-closure scheme overestimates the contribution from the velocity-dependent terms in the semitransparent region. [ABSTRACT FROM AUTHOR]

Determining the electron neutrino mass by electron capture in 163Ho relies on an accurate understanding of the differential electron capture nuclear decay rate as a function of the distribution of the total decay energy between the neutrino and electronic excitations. The resulting spectrum is dominated by resonances due to local atomic multiplet states with core holes. Coulomb scattering between electrons couples the discrete atomic states, via Auger–Meitner decay, to final states with free electrons. The atomic multiplets are above the auto-ionisation energy, such that the delta functions representing these discrete levels turn into a superposition of Lorentzian, Mahan- and Fano-like line-shapes. We present an ab initio method to calculate nuclear decay modifications due to such processes. It includes states with multiple correlated holes in local atomic orbitals interacting with unbound Auger–Meitner electrons. A strong energy-dependent, asymmetric broadening of the resonances in good agreement with recent experiments is found. We present a detailed analysis of the mechanisms determining the final spectral line-shape and discuss both the Fano interference between different resonances, as well as the energy dependence of the Auger–Meitner Coulomb matrix elements. The latter mechanism is shown to be the dominant channel responsible for the asymmetric line-shape of the resonances in the electron capture spectrum of 163Ho. [ABSTRACT FROM AUTHOR]

We investigate baryogenesis via leptogenesis in an A4 flavor model within the paradigm of type-I and II seesaw mechanism resulting in a magic neutrino mass matrix with broken μ − τ symmetry in a minimal scenario with two right-handed neutrinos (2RHN). Additional Z3 cyclic symmetry is employed to constrain the Yukawa structure of the model. The type-II seesaw terms play a crucial role in generating non-degenerate neutrino masses and non-zero θ13 and contribute to baryogenesis. In particular, after the spontaneous symmetry breaking, the Yukawa couplings and are responsible for the breaking of μ − τ symmetry. The effective Majorana neutrino mass is found to be well within the sensitivity reach of the 0νββ experiments, in particular, for inverted hierarchy. The model has an imperative implication for inverted hierarchy, for example, the non-observation of this process at nEXO will rule out IH. The predicted baryon asymmetry is in good agreement with the observed baryon asymmetry for NH whereas IH is disallowed at 2.5σ C.L. [ABSTRACT FROM AUTHOR]

Simple extensions of the standard model (SM) with additional right handed neutrinos (RHNs) can elegantly explain the existence of small neutrino masses and their flavor mixings. Collider searches for sterile neutrinos are being actively pursued currently. Heavy RHNs may dominantly decay into after being produced at the LHC. In this paper, we consider collider signatures of heavy pseudo-Dirac neutrinos in the context of the inverse seesaw scenario, with a sizable mixing with the SM neutrinos under two different flavor structures, viz. flavor diagonal and flavor non-diagonal (FND) scenarios. For the latter scenario we use a general parametrization for the model parameters by introducing an arbitrary orthogonal matrix and nonzero Dirac and Majorana phases. We then perform a parameter scan to identify allowed parameter regions which satisfy all experimental constraints. As an alternative channel to the traditional trilepton signature, we propose the opposite-sign di-lepton signature in the final state, in association with a fat jet from the hadronic decay of the boosted. We specifically consider a fat jet topology and explore the required enhancements from exploiting the characteristics of the jet substructure techniques. We perform a comprehensive collider analysis to demonstrate the effectiveness of this channel in both of the scenarios, significantly enhancing the bounds on the RHN mass and mixing angles at the 13 TeV LHC. Interestingly the FND scenario can reach up to a 5-σ limit under the presence of the general parametrization at the high luminosity LHC. [ABSTRACT FROM AUTHOR]

By allowing gauge anomaly cancellation between fermions in different families we find a non-universal solution for a Z′ family of models with the same content of fermions of the standard model plus three right-handed neutrinos. We also impose constraints from the Yukawa interaction terms in such a way that at the end we obtain a solution with six free parameters. Our solution contains as particular cases well-known models in the literature. As an application, we report a model that evades LHC constraints, flavor changing neutral currents and low energy constraints. Simultaneously, the model is able to explain the flavor anomalies in the Wilson coefficients C9(μ) and C10(μ) without modifying the corresponding Wilson coefficients for the first family. In our approach, this procedure is always possible for Z′ masses smaller than ∼2.5 TeV. [ABSTRACT FROM AUTHOR]

In this work, we present the first spectroscopic measurements of conversion electrons originating from the decay of metastable gaseous 83mKr with the Karlsruhe Tritium Neutrino (KATRIN) experiment. The obtained results represent one of the major commissioning milestones for the subsequent direct neutrino mass measurement with KATRIN. The successful campaign demonstrates the functionalities of the KATRIN beamline. Precise measurement of the narrow K-32, L3-32, and N2,3-32 conversion electron lines allowed to verify the eV-scale energy resolution of the KATRIN main spectrometer necessary for competitive measurement of the absolute neutrino mass scale. [ABSTRACT FROM AUTHOR]

We propose and discuss a new Littlest Seesaw model, realized in the tri-direct CP approach, in which the couplings of the two right-handed neutrinos to the lepton doublets are proportional to (0, −1, 1) and (1,5/2, −1/2) respectively with the relative phase η = −π/2. This model can give an excellent description of lepton flavour mixing, including an atmospheric neutrino mixing angle in the second octant, in terms of only two input parameters. We show that the observed baryon asymmetry can be generated for the lightest right-handed neutrino mass M1 = 1.176 × 1011 GeV in SM and M1 = 3.992 × 1010 GeV in MSSM with. We construct an explicit Littlest Seesaw model based on the flavour symmetry S4 × Z5 × Z8 in which the desired alignments and the phase η = −π/2 are achieved. [ABSTRACT FROM AUTHOR]

Adopting the 3 + 1 neutrino mixing parameters by the IceCube and short baseline experiments, we investigate the sterile–active neutrino oscillation effects on the supernova neutrino process. For the sterile neutrino (νs), we study two different luminosity models. First, we presume that the νs does not interact with other particles through the standard interactions apart from the oscillation with the active neutrinos. Second, we consider the νs directly produced by νe scattering with the matter. In both cases, we find that the pattern of neutrino oscillations drastically impacts on the νs in supernova environments. In particular multiple resonances occur, and consequently affect thermal neutrino-induced reaction rates. As a result, 7Li, 7Be, 11B, 11C, 92Nb, 98Tc, and 138La yields in the ν-process change. Among those nuclei, we constrain the 7Li and 11B yields using the analysis of observed SiC X grains. Based on the meteoritic data, we conclude that the second model can be allowed, while the first model is excluded. The viability of the second model depends on the sterile neutrino temperature and the neutrino mass hierarchy. [ABSTRACT FROM AUTHOR]

We revisit the accretion-induced collapse (AIC) process, in which a white dwarf collapses into a neutron star. We are motivated by the persistent radio source associated with the fast radio burst FRB 121102, which was explained by Waxman as a weak stellar explosion with a small (∼10−5 M⊙) mildly relativistic mass ejection that may be consistent with AIC. Additionally, the interaction of the relatively low ejected mass with a pre-collapse wind might be related to fast optical transients. The AIC is simulated with a one-dimensional, Lagrangian, Newtonian hydrodynamic code. We put an emphasis on accurately treating the equation of state and the nuclear burning, which is required for any study that attempts to accurately simulate AIC. We leave subjects such as neutrino physics and general relativity corrections for future work. Using an existing initial profile and our own initial profiles, we find that the ejected mass is ∼10−2 to 10−1 M⊙ over a wide range of parameters, and we construct a simple model to explain our results. [ABSTRACT FROM AUTHOR]

A new diagnostics to break the degeneracy between the total neutrino mass (Mν) and the primordial power spectrum amplitude (σ8) using the drifting coefficient of the field cluster mass function is presented. Analyzing the data from the Cosmological Massive Neutrino Simulations, we first determine the numerical mass functions of the field clusters at various redshifts. Then, we compare the numerical results with the analytical model characterized by a single parameter called the drifting coefficient, which measures the drifts of the collapse density threshold, δc, from the Einstein–de Sitter spherical value, δsc, at a given mass scale. It is found that the analytic model for the field cluster mass function is found to work excellently even in the presence of massive neutrinos, and that its drifting coefficient evolves differently in the cosmologies with different values of Mν. At low redshifts (z ≲ 0.3) the more massive neutrinos drift δc further from δsc, while the opposite trend is found at higher redshifts (z ≳ 0.3). Speculating that this distinct redshift-dependent effect of massive neutrinos on the drifting coefficient of the field cluster mass function might help break the σ8–Mν degeneracy, we also show that the sensitivity of this new diagnostics to Mν is high enough to discriminate the case of Mν = 0.1 eV from that of massless neutrinos. [ABSTRACT FROM AUTHOR]

Leptogenesis appears to be a viable alternative to account for the baryon asymmetry of the Universe through baryogenesis. In this context, we consider a scenario in which the standard model is extended with S3 and Z2 symmetry in addition to the two scalar triplets, two scalar doublets and three right-handed neutrinos. Presence of scalar triplets and right-handed neutrinos in the scenarios of both type-I and type-II seesaw frameworks provide a different leptogenesis option and can help us to understand the matter-antimatter asymmetry with simple S3 symmetry. We discuss the neutrino phenomenology and leptogenesis in both high (O(1010) GeV) and low energy scale (O(2) TeV) by constraining the Yukawa couplings. Moreover, we also consider the constraints on model parameters from neutrino oscillation data and leptogenesis to explain the rare lepton flavor violating decay and muon g-2 anomaly. [ABSTRACT FROM AUTHOR]

We propose a renormalizable B − L standard model extension based on D4 symmetry which accommodates fermion mass and mixing parameters with CP violation. Both normal and inverted neutrino mass ordering as well as the smallness of the active neutrino masses are generated through a type I seesaw mechanism. The obtained physical parameters are well consistent with the global fit of neutrino oscillation in Esteban et al (2019 J. High Energy Phys. JHEP01(2019)106) while the quark masses are in good agreement with the recent experimental data (Tanabashi et al (Particle Data Group) 2018 Phys. Rev. D 98 030001 and 2019 update). The model also predicts an effective neutrino mass parameter of for normal hierarchy and for inverted hierarchy which are all consistent with the recent experimental limits on neutrinoless double beta decay. [ABSTRACT FROM AUTHOR]

Nuclear matrix elements (NMEs) for double beta decays (DBDs) are crucial for studying the neutrino mass and other neutrino properties beyond the standard electro-weak model by measuring neutrino-less DBDs. The spin-dipole (SD) Jπ = 2− NME is one of the major components associated with the DBD NME. The SD NME for 76Ge was derived for the first time by using the 74,76 Ge (3He, t) at RCNP Osaka. The obtained SD NME for the 76Ge → 76As ground-state transition is in natural units. This is smaller by a coefficient around k ≈ 0.2 with respect to the quasi-particle model NME. The impact of the reduced (quenched) SD NME on DBD neutrino studies is discussed. [ABSTRACT FROM AUTHOR]

In this paper, we study the viability of having a fermion Dark Matter particle below the TeV mass scale in connection to the neutrino mass generation mechanism. The simplest realisation is achieved within the scotogenic model where neutrino masses are generated at the 1-loop level. Hence, we consider the case where the dark matter particle is the lightest -odd Majorana fermion running in the neutrino mass loop. We assume that lepton number is broken dynamically due to a lepton number carrier scalar singlet which acquires a non-zero vacuum expectation value. In the present scenario the Dark Matter particles can annihilate via t- and s-channels. The latter arises from the mixing between the new scalar singlet and the Higgs doublet. We identify three different Dark Matter mass regions below 1 TeV that can account for the right amount of dark matter abundance in agreement with current experimental constraints. We compute the Dark Matter-nucleon spin-independent scattering cross-section and find that the model predicts spin-independent cross-sections 'naturally' dwelling below the current limit on direct detection searches of Dark Matter particles reported by XENON1T. [ABSTRACT FROM AUTHOR]

Since its inception, no decisive departure from the predictions of the standard model (SM) has been reported. However, recently various experiments have observed a few hints of possible departure from SM predictions in lepton flavor universality observables such as , , muon (g–2), , etc. Many of these are observable where deviation from the SM in the range of (2–4)σ is observed related to the muon (μ) lepton. So these deviations may hint at a possible new physics (NP) in the muon sector. In this work we extend the SM by introducing two SM singlet heavy charged leptons (Fe, Fμ), whose left-handed components are charged under a new U(1)F gauge symmetry, one color triplet lepto-quark (ϕQ) doublet under SU(2)L, one inert Higgs doublet (ϕl), and three very heavy Majorana neutrinos (NiR), all of which are odd under a Z2 discrete symmetry. One more scalar (ϕ) charged only under the U(1)F, whose VEV gives masses to the U(1)F gauge boson as well as the heavy leptons. With these new particles, we show that the observed anomalies in the muon sector as well as small neutrino masses can be explained taking into account all the other experimental and theoretical constraints to date. [ABSTRACT FROM AUTHOR]

Various thermodynamic quantities for baryon-free matter are calculated by combining the most reliable non-perturbative and perturbative calculations, especially the most recent ones including as many quark flavors as possible. We extend these calculations by including other degrees of freedom (dof), such as photons, neutrinos, leptons, electroweak particles and Higgs bosons, which allows us to consider temperatures up to the TeV-scale. The calculations show that similar to QCD, the EW phase transition is also a crossover. We have found that while the equation of state for the hadronic matter is linear, , the one for higher temperatures is rather complex; it exhibits two crossover-type phase transitions, corresponding to strong and EW matter. At even larger energy densities, the deduced EoS becomes linear again and close to ideal gas. Analytical parameterizations of obtained results are presented. The combined equation of state can be used for modelling the expansion of the Universe from very early times and through the EW and QCD era. [ABSTRACT FROM AUTHOR]

We construct two viable extensions of the SM with a heavy vector in the fundamental representation and nine SM singlet scalar fields, consistent with the current SM fermion mass spectrum and fermionic mixing parameters. The small masses for the active neutrinos are generated from radiative seesaw mechanism at one loop level mediated by the neutral components of the heavy vector as well as by the left-handed Majorana neutrinos. The proposed models predicts rates for charged lepton flavor violating processes within the reach of the forthcoming experiments. [ABSTRACT FROM AUTHOR]

We consider the minimal 3-3-1 model adding three right-handed neutrinos that transform as singlet under the SU(3)L ⨂ U(1)X symmetry. This model predicts flavor violating interactions in both quark and lepton sectors, since all the charged fermions mass matrices cannot be assumed diagonal in any case. Here we accommodate the lepton masses and the Pontecorvo–Maki–Nakagawa–Sakata matrix at the same time, and as a consequence the Yukawa couplings and the unitary matrices which diagonalize the mass matrices are no longer parameters. We study some phenomenological consequences, i.e., and li → ljγ which are induced by the neutral and doubly charged particles present in the model. In particular we show that if is observed in the future, the only particle in the model that could explain this decay is the doubly charged vector bilepton mediator, because the contribution due to the doubly charged and neutral scalars is suppressed. [ABSTRACT FROM AUTHOR]

The model with lepton flavor non-universality can generate the active neutrino masses via the Zee mechanism, which predicts the existence of the charged Higgs bosons by introducing new free parameters and Mh where i, j denote e, μ, or τ. We calculate the contributions of to the , , and decays, and extract individual constraints on the factor /Mh by combining the current experimental measurements. We find that can provide more stringent constraints on /Mh than , while the obtained constraints on /Mh are comparable from these decays. The contributions of to the muon anomalous magnetic moment aμ and non-standard interactions of neutrinos are also discussed. [ABSTRACT FROM AUTHOR]

Sterile neutrinos appear in minimal extensions of the Standard Model of particle physics. If their mass is in the keV regime, they are viable dark matter candidates. One way to search for sterile neutrinos in a laboratory-based experiment is via the analysis of β-decay spectra, where the new neutrino mass eigenstate would manifest itself as a kink-like distortion of the β-decay spectrum. The objective of the TRISTAN project is to extend the KATRIN setup with a new multi-pixel silicon drift detector system to search for a keV-scale sterile neutrino signal. In this paper we describe the requirements of such a new detector, and present first characterization measurement results obtained with a 7 pixel prototype system. [ABSTRACT FROM AUTHOR]