Haut PDF Probing physics beyond the standard model in diatomic molecules

Probing physics beyond the standard model in diatomic molecules

Probing physics beyond the standard model in diatomic molecules

is deeply bound which is an experimental advantage. The magnetic moment in the Ω = 1 component of this term is approximately zero which helps reduce the vulnerability of the experiment to decoherence and systematic errors [LBL + 11]. HfF + and ThF + exhibit a considerably large EDM effective electric field in the relevant “science” state [PMIT07, FN13, MB08] and, at the same time, a small Λ (or Ω) doublet splitting. This latter property is an asset for efficient mixing of rotational parity eigenstates through the external electric laboratory field. While HfF + , already employed in an eEDM experiment [LBL + 11], has been characterized in detail [AHT04, BABH11, PMIT07, PMT09, SMPT08, FN13] considerably less is known for ThF + [MB08, BAHP12, Iri12]. The joint experimental and theoretical work of Barker et al. [BAHP12] left some uncertainty as to whether the Ω = 1 state is the ground-state or the first excited state, as there is an Ω = 0 + state ( 1 Σ + 0 ) separated from it by only 315 cm −1 . The experimental resolution was not sufficient to unequivocally assign those states and, unlike HfF + , the Ω = 1 and 0 + states of ThF + possess similar vibrational frequencies at around 658 cm −1 . Accompanying theoretical calculations were also inconclusive, but from the best estimate the Ω = 0 + state was proposed as ground state with the Ω = 1 state higher by 65 cm −1 in Reference [BAHP12] and 202 cm −1 in Reference [HBA14a], respectively.
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Search for physics beyond the standard model in events with two leptons of same sign, missing transverse momentum, and jets in proton–proton collisions at $\sqrt{s} = 13\,\text {TeV} $

Search for physics beyond the standard model in events with two leptons of same sign, missing transverse momentum, and jets in proton–proton collisions at $\sqrt{s} = 13\,\text {TeV} $

Fig. 10 Correlations between the background predictions in the 15 exclusive regions luminosity of 35.9 fb −1 , has been studied to search for mani- festations of physics beyond the standard model. The data are found to be consistent with the standard model expectations, and no excess event yield is observed. The results are inter- preted as limits at 95% confidence level on cross sections for the production of new particles in simplified supersymmetric models. Using calculations for these cross sections as func- tions of particle masses, the limits are turned into lower mass limits that are as high as 1500 GeV for gluinos and 830 GeV for bottom squarks, depending on the details of the model. Limits are also provided on the production of heavy scalar (excluding the mass range 350–360 GeV) and pseudoscalar (350–410 GeV) bosons decaying to top quarks in the context of two Higgs doublet models, as well as on same-sign top quark pair production, and the standard model production of four top quarks. Finally, to facilitate further interpreta- tions of the search, model-independent limits are provided as a function of H T and E T miss , together with the background prediction and data yields in a smaller set of signal regions. Acknowledgements We congratulate our colleagues in the CERN
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Search for Physics Beyond the Standard Model in Events with High-Momentum Higgs Bosons and Missing Transverse Momentum in Proton-Proton Collisions at 13 TeV

Search for Physics Beyond the Standard Model in Events with High-Momentum Higgs Bosons and Missing Transverse Momentum in Proton-Proton Collisions at 13 TeV

DOI: 10.1103/PhysRevLett.120.241801 Primary motivations for building the CERN LHC [1] were to determine the source of electroweak symmetry breaking and to search for physics beyond the standard model (SM). In 2012, the first goal was achieved with the discovery of the Higgs boson H by the ATLAS and CMS Collaborations [2 – 4] . In this Letter, we exploit that discovery in a search for events containing high-momentum Higgs bosons in con- junction with hadronic jets and missing momentum trans- verse to the beam, ⃗p miss T . Large p miss T ≡ j⃗p miss T j can arise from the production of energetic weakly interacting particles that escape detection. A new particle of this type would be a candidate for weakly interacting massive particle (WIMP) dark matter [5–7] . High-momentum Higgs bosons appear rarely in SM processes, and would provide a unique signature of new physics. Such a signature can arise in a variety of models for physics beyond the SM, including extended electroweak sectors [8,9] , extended Higgs sectors [10] , and supersymmetry (SUSY) [11,12] .
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Efficient Probabilistic Inference in the Quest for Physics Beyond the Standard Model

Efficient Probabilistic Inference in the Quest for Physics Beyond the Standard Model

[4] V. M. Abazov et al. A precision measurement of the mass of the top quark. Nature, 429:638–642, 2004. [5] J. Allison, K. Amako, J. Apostolakis, P. Arce, M. Asai, T. Aso, E. Bagli, A. Bagulya, S. Banerjee, G. Barrand, B. Beck, A. Bogdanov, D. Brandt, J. Brown, H. Burkhardt, P. Canal, D. Cano-Ott, S. Chauvie, K. Cho, G. Cirrone, G. Cooperman, M. Cortés-Giraldo, G. Cosmo, G. Cuttone, G. Depaola, L. Desorgher, X. Dong, A. Dotti, V. Elvira, G. Folger, Z. Francis, A. Galoyan, L. Garnier, M. Gayer, K. Genser, V. Grichine, S. Guatelli, P. Guèye, P. Gumplinger, A. Howard, I. Hˇrivnáˇcová, S. Hwang, S. Incerti, A. Ivanchenko, V. Ivanchenko, F. Jones, S. Jun, P. Kai- taniemi, N. Karakatsanis, M. Karamitros, M. Kelsey, A. Kimura, T. Koi, H. Kurashige, A. Lech- ner, S. Lee, F. Longo, M. Maire, D. Mancusi, A. Mantero, E. Mendoza, B. Morgan, K. Mu- rakami, T. Nikitina, L. Pandola, P. Paprocki, J. Perl, I. Petrovi´c, M. Pia, W. Pokorski, J. Quesada, M. Raine, M. Reis, A. Ribon, A. R. Fira, F. Romano, G. Russo, G. Santin, T. Sasaki, D. Sawkey, J. Shin, I. Strakovsky, A. Taborda, S. Tanaka, B. Tomé, T. Toshito, H. Tran, P. Truscott, L. Urban, V. Uzhinsky, J. Verbeke, M. Verderi, B. Wendt, H. Wenzel, D. Wright, D. Wright, T. Yamashita, J. Yarba, and H. Yoshida. Recent developments in GEANT4. Nuclear Instruments and Meth- ods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 835(Supplement C):186 – 225, 2016.
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Primary processes: from atoms to diatomic molecules and clusters

Primary processes: from atoms to diatomic molecules and clusters

2.1.4. Using COLTRIMS. A preliminary study of multiple capture processes in low energy (105 keV) N 7+ + Ne collision was also attempted using the COLTRIMS technique [71]. The resolution in Q- value that can be achieved with this technique cannot compete with high resolution electron spectroscopy or photon spectroscopy, but the measurement in coincidence of the charge states of both the projectile and the recoil ion gives direct access to capture multiplicity and to the stabilization ratios of the captured electrons. In this experiment, the branching ratios for configurations populated by the single and double capture processes could be clearly resolved and quantified. For the capture of three, four and five electrons, the populated configurations could be identified but the associated branching ratios could not be accurately determined. However, it was clearly shown that triple-, quadruple-, and quintuple-electron capture populate double Rydberg states and prefer to be doubly stabilized, with two electrons remaining on the scattered projectile while the others are ejected by Auger emission. With more than two active electrons, the number of channels leading to multiple capture becomes too large to be treated theoretically within the quasimolecular description and using close coupling standard calculations. Only the COBM [63] and a semi empirical model [72] could be used to describe these processes and be compared with the experimental results. These models predict a triple-electron capture stronger than the quadruple-electron capture, what was found to be in complete disagreement with the experimental results. This implies that electon-electron interaction, not included in these oversimplified calculations, may play an important role in multiple capture.
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Current status of the Standard Model CKM fit and constraints on $\Delta F=2$ New Physics

Current status of the Standard Model CKM fit and constraints on $\Delta F=2$ New Physics

cisely (1 + y s ) = 1.07 discussed in refs. [31–33]. III. RESULTS OF THE SM GLOBAL FIT A. CKM parameters and Unitarity Triangles The current situation of the global fit in the ( ¯ ρ, ¯ η) plane is indicated in Fig. 4. Some comments are in order be- fore discussing the metrology of the parameters. There exists a unique preferred region defined by the entire set of observables under consideration in the global fit. This region is represented by the yellow surface inscribed by the red contour line for which the values of ¯ ρ and ¯ η with a p-value such that 1 − p < 95.45 %. The goodness of the fit can be addressed in the simplified case where all the inputs uncertainties are taken as Gaussian, with a p-value found to be 66% (i.e., 0.4 σ; a more rigorous derivation of the p-value in the general case is beyond the scope of this article [34]). One obtains the following values (at 1σ) for the 4 parameters describing the CKM matrix:
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Quantum Population Dynamics: A Broad View from an Exploration beyond the Standard Model

Quantum Population Dynamics: A Broad View from an Exploration beyond the Standard Model

Abstract: To explore quantum and classical connection from a new perspective, a Quantum Population Dynamics (QPoD) model based on the logistic relation common to several sciences is investigated from a very broad perspective to explore the numerous links to current physics. From postulates of causality and finiteness a classical quantum entity, a quanta of spacetime, is defined with unitary extension and intensity. Applying the logistic equation to a quantum population of non-local two-state oscillators results in a quantum-classical equation linking wave and particle dynamics with an explicit account of decoherence. Varying over 124 orders of magnitude, the coupling constant acts like a delta Dirac function between regimes. The quantum regime is conform to Schr¨odinger and Dirac equations according to respective Hamiltonian while the classical mode suppresses the quantum wave function and follows the Hamilton-Jacobi equation. Besides the quantum wave solutions, in the classical range, the general equation admits Fermi-Dirac and Bose-Einstein solutions, relating to thermodynamics. Inertial mass is found in terms of the quantum entropy gradient. The most compact quantum cluster forming a crystal produces a unique flat space filling lattice cells of one simple tetrahedron and one composite truncated tetrahedron corresponding respectively to a fermionic cell and a bosonic cell. From this lattice geometry alone, the mass ratios of all fermions are expressed uniquely in terms of vertices and faces, matching charges properties of three generations and three families. Except for a minor degeneracy correction, the solution is shown to follow the logistic dynamics. The resulting mass equation is a function of dimensionless natural numbers. Many properties of the Standard Model are recovered from geometry at the Planck scale, respecting naturalness, uniqueness and minimality. QPoD may help addressing questions about the nature of spacetime and the physical microstructure of particles. The model predicts a single spinless matter particle of a 4th generation as a WIMP particle close to Higgs mass.
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Beyond-Standard-Model Tensor Interaction and Hadron Phenomenology

Beyond-Standard-Model Tensor Interaction and Hadron Phenomenology

DOI: 10.1103/PhysRevLett.115.162001 PACS numbers: 13.60.Hb, 13.40.Gp, 24.85.+p High precision measurements of beta decay observables play an important role in beyond the standard model (BSM) physics searches, as they allow us to probe couplings other than of the V − A type, which could appear at the low energy scale. Experiments using cold and ultracold neutrons [1 –4] , nuclei [5 –8] , and meson rare decays [9] are being performed, or have been planned, that can reach the per-mil level or even higher precision. Effective field theory (EFT) allows one to connect these measurements and BSM effects generated at TeV scales. In this approach that complements collider searches, the new interactions are introduced in an effective Lagrangian describing semileptonic transitions at the GeV scale including four-fermion terms, or operators up to dimension six for the scalar, tensor, pseudoscalar, and V þ A interactions (for a review of the various EFT approaches, see Ref. [10] ). Because the strength of the new interactions is defined with respect to the strength of the known SM interaction, the coefficients of the various terms, ϵ i ,
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Beyond the Standard Litany: Losp and Higgs Portals; Lattice Lattice Gauge Theory

Beyond the Standard Litany: Losp and Higgs Portals; Lattice Lattice Gauge Theory

GeV. The unification will continue to work if we include additional complete SO(10) multiplets with intermediate masses, though the scale will be modified. In this way, by addressing the first shortcoming of the standard model, we are led to a won- derful expectation, that superpartners should be accessible to the LHC. As a bonus, we find that several other shortcomings have also been addressed. Small but non-zero neutrino masses are gen- erated naturally, by the seesaw mechanism. SO(10) gives us the SU (3) × SU (2) × U (1) singlet “right-handed neutrino” we need, and the unification scale motivates its required large mass. The enormous energy scale for unification, which emerges from the phenomenology of particle physics, is close to the Planck scale of gravity. This means that the powers of all four basic interactions approach equality. This is a most remarkable result, since at practically accessible energies and distances gravity is absurdly weak compared to the other basic interactions among fundamental particles. Low-energy supersymmetry also, in many implementations, produces promising candi- dates to provide the astronomers’ dark matter. So by relieving the first shortcoming of the standard model on our list we seem to make progress on the subsequent three, as well.
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Bs→Dsℓνℓ near zero recoil in and beyond the Standard Model

Bs→Dsℓνℓ near zero recoil in and beyond the Standard Model

formation about the scalar form factor [27]. Since then, a number of studies appeared trying to ex- plain that discrepancy by interpreting it as a po- tential signal of New Physics (NP) [28, 29]. In the models with two Higgs doublets (2HDM), the charged Higgs boson can mediate the tree level pro- cesses, including B → D`ν, and considerably en- hance the coefficient multiplying the scalar form factor in the decay amplitude. For that reason it becomes important to get a lattice QCD estimate of f 0 (q 2 ). Furthermore, the model independent con-
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Beyond Benchmarking - How Experiments and Simulations Can Work Together in Plasma Physics

Beyond Benchmarking - How Experiments and Simulations Can Work Together in Plasma Physics

2. Case Studies Numerous case studies exist which illustrate the synergy between experimental and computational/theoretical research. Consider the course of research into the role of ITG (Ion Thermal Gradient) turbulence and transport in tokamak plasmas. Earlier work on the Alcator experiments showed a clear decrease in transport as the plasma density was raised [4]. However, subsequent studies on Alcator-C found that this effect saturated at a relatively low density. During the same period, theoretical and computation studies suggested that important instabilities were excited when η i , the ratio of density profile scale length, to temperature profile scale length exceeded a critical value on the order of 1 [5]. It was predicted that plasmas with steeper density profiles would be immune to this instability and thus might have lower levels of transport. Experiments to test this prediction were carried out using injection of high-speed deuterium pellets to fuel the plasma core and peak the density. The result was a dramatic drop in energy and particle transport consistent with predictions[6]. These experiments, among other results, spurred interest and activity in a class of instabilities and turbulence which are now believed to be the principle cause of anomalous transport in tokamaks. Experimental observation of transport “barriers” in the core and edge [7-10] motivated theoretical research into stabilization mechanisms. Out of this work, a new paradigm arose in which sheared plasma flows were seen as the principle agent of ITG turbulence regulation and suppression [11]. While far from complete, this theory is now thestandard model” for anomalous ion transport.
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Beyond the Standard Model Physics at the HL-LHC and HE-LHC

Beyond the Standard Model Physics at the HL-LHC and HE-LHC

3.1.2 Monojet Signatures from Heavy Coloured Particles at HL- and HE-LHC Contributors: A. Chakraborty, S. Kuttimalai, S. H. Lim, M. M. Nojiri, and R. Ruiz Search strategies for hypothetical coloured particles Q that can decay to dark matter candidates usually involve jets and leptons produced in association with large missing transverse energy E T miss . In compressed mass spectrum scenarios the visible decay products in the Q →DM+SM process do not have sufficient momenta to be readily distinguished from SM backgrounds and monojet-like topologies arise. Were evidence for a new particle Q established at the LHC, or a successor experiment such as the HE-LHC, it would be crucial to determine the properties of Q, especially its mass, spin, and colour rep- resentation, in order to help understand the nature of DM. Such a program would typically include inves- tigating various collider observables that can discriminate against possible candidates for Q, and hence requires that observables are known to sufficiently high precision. It is the case though that leading order (LO) calculations are poor approximations for QCD processes, even when using sensible scale choices. The situation, however, is more hopeful with the advent of general-purpose precision Monte Carlo event generators H ERWIG [ 194 ], M AD G RAPH 5_ A MC@NLO+P YTHIA 8 [ 67 , 68 ], and SHERPA [ 195 ]. With automated event generation up to NLO in QCD with parton shower (PS) matching and multijet merg- ing, even for BSM processes [ 196 ], one can now systematically investigate the impact of crucial O(α s ) corrections on the inclusive monojet process.
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Diffuse Ultra-High Energy Neutrino Fluxes and Physics Beyond the Standard Model

Diffuse Ultra-High Energy Neutrino Fluxes and Physics Beyond the Standard Model

3 The spectra shown here is unrealistic and chosen only to demon- strate the effect of standard oscilaltions on even such widely differing flavour fluxes. [43]. Additionally, if quantum gravity demands a funda- mental length scale, leading to a breakdown of special rel- ativity, or loop quantum gravity [44–49] leads to discrete space-time , one expects tiny LV effects to percolate to lower energies. For a recent discussion see [50] and ref- erences therein. UHE neutrinos, with their high energies and long oscillation baselines present a unique opportu- nity for testing these theories. Their effects in the context of flavour flux ratios have been discussed in [22]. Here we demonstrate their effects on diffuse UHE fluxes (or equiva- lently, on the bounds thereon) by a representative calcula- tion. For specificity we pick the low energy limit of string theory represented by the Standard model Extension [42] and the corresponding modified dispersion relation im- plied by it. We consider, for simplicity, the two-flavour case with ν µ − ν τ oscillations and a single real off-diagonal Lorentz and CPT violating parameter a with dimensions of mass, which modifies the effective hamiltonian (in the mass eigenstate basis) to
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Beyond Standard Model Searches in the MiniBooNE Experiment

Beyond Standard Model Searches in the MiniBooNE Experiment

The MiniBooNE experiment has contributed substantially to beyond standard model searches in the neutrino sector. The experiment was originally designed to test the Δ𝑚 2 ∼ 1 eV 2 region of the sterile neutrino hypothesis by observing ] 𝑒 (] 𝑒 ) charged current quasielastic signals from a ] 𝜇 (] 𝜇 ) beam. MiniBooNE observed excesses of ] 𝑒 and ] 𝑒 candidate events in neutrino and antineutrino mode, respectively. To date, these excesses have not been explained within the neutrino standard model (]SM); the standard model extended for three massive neutrinos. Confirmation is required by future experiments such as MicroBooNE. MiniBooNE also provided an opportunity for precision studies of Lorentz violation. The results set strict limits for the first time on several parameters of the standard-model extension, the generic formalism for considering Lorentz violation. Most recently, an extension to MiniBooNE running, with a beam tuned in beam-dump mode, is being performed to search for dark sector particles. This review describes these studies, demonstrating that short baseline neutrino experiments are rich environments in new physics searches.
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Probing the scotogenic model with lepton flavor violating processes

Probing the scotogenic model with lepton flavor violating processes

5 Conclusions 21 A Loop functions 22 1 Motivation The experimental bounds on lepton flavor violating processes will be greatly improved in the near future [ 1 ]. For lepton flavor violating τ decays, such as τ → `γ and τ → 3 `, the ex- pected future sensitivity is about one order of magnitude below their present limits, which already exclude branching ratios larger than about 10 −8 . In the µ-e sector, current limits are more stringent and the expected improvements are more significant. For µ → 3 e a sen- sitivity four orders of magnitude below the present bound is foreseen, while the limit on µ-e conversion in nuclei could be increased by up to six orders of magnitude. Even for µ → eγ, which currently provides the strongest bound, a one order of magnitude improvement is expected in the near future. Given that the present limits on some of these processes are already very impressive and can restrict the parameter space of new physics models in an important way, one can only wonder about the impact that these future experimental im- provements might have on such models. Could they exclude some scenarios? How will they affect their viable parameter space? In this paper, we address precisely these issues within a specific and well-motivated extension of the Standard Model: the scotogenic model.
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Evolvability signatures of generative encodings: beyond standard performance benchmarks

Evolvability signatures of generative encodings: beyond standard performance benchmarks

. Numerous encod- ings have been proposed in ER, taking inspiration from nat- ural developmental processes, in particular, to evolve con- trol systems for robots (e.g., Gruau (1994); Kodjabachian and Meyer (1998); Clune et al. (2009a); Cheney et al. (2013); Lee et al. (2013); Lewis et al. (1992); Morse et al. (2013)). Given the multitude of available encodings, it is crucial to compare them and understand their differences, so that the ER com- munity can focus on the most promising ones. In the selec- tion of encodings investigated in our study, both direct and generative schemes are considered. Direct encodings encom- pass a one-to-one mapping between genes and phenotypic traits, and are the simplest form of encoding thus serving as a reference for comparison (e.g., Koos et al. (2013)). We also evaluate the more complex generative encodings character- ized by a one-to-many mapping between genes and pheno- typic traits, i.e., a single gene describes several phenotypic traits (Stanley and Miikkulainen, 2002; Stanley, 2007). These state of the art encodings are expected to exploit geomet- ric information of the robot morphology to generate regular and modular phenotypic patterns (e.g., (Stanley et al., 2009; Clune et al., 2011; Morse et al., 2013)).
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Search for the standard model Higgs boson in tau final states

Search for the standard model Higgs boson in tau final states

in the combined τ ν and τ τ analyses. This is the first limit on SM Higgs production using final states involving hadronically decaying tau leptons. These results contribute to the sensitivity of the combined Tevatron search for low mass Higgs bosons [2]. We thank the staffs at Fermilab and collaborating institutions, and acknowledge sup- port from the DOE and NSF (USA); CEA and CNRS/IN2P3 (France); FASI, Rosatom and RFBR (Russia); CNPq, FAPERJ, FAPESP and FUNDUNESP (Brazil); DAE and DST (In- dia); Colciencias (Colombia); CONACyT (Mexico); KRF and KOSEF (Korea); CONICET and UBACyT (Argentina); FOM (The Netherlands); STFC and the Royal Society (United Kingdom); MSMT and GACR (Czech Republic); CRC Program, CFI, NSERC and West- Grid Project (Canada); BMBF and DFG (Germany); SFI (Ireland); The Swedish Research Council (Sweden); CAS and CNSF (China); and the Alexander von Humboldt Foundation (Germany).
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Ultra-high neutrino fluxes as a probe for non-standard physics

Ultra-high neutrino fluxes as a probe for non-standard physics

investigations of the effects of pseudo-Dirac neutrinos and decoherence in the last two sections. 2 The diffuse neutrino flux from Active Galactic Nuclei Active galactic nuclei are extremely distant galactic cores having very high densities and temperatures. Due to the high temperatures and the presence of strong electromagnetic fields, AGN’s act as accelerators of fundamental particles, driving them to ultra-high en- ergies (> 1000 GeV). The acceleration of electrons as well as protons (or ions) by strong magnetic fields in cosmic accelerators like AGN’s leads to neutrino production. Specifically, accelerated electrons lose their energy via synchrotron radiation in the magnetic field leading to emission of photons that act as targets for the accelerated protons to undergo photo- hadronic interactions. This leads to the production of mesons which are unstable and decay. In the standard case the charged pions decay primarily contributing to neutrino production
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About the choice of a turbulence model in building physics simulations

About the choice of a turbulence model in building physics simulations

Case 4: Radiation Case Results of this case are drawn at Figure 7. The agreement is still quite good; the mean error is indeed less than 0.2°C for each turbulence models. One more time, there is no big differences between different turbulence models. It is interesting to see the impact of the near-wall treatment. Indeed, k-ε model is here based on wall functions. It is not the case for k-ω model, thanks to a low-Reynolds correction. So, it can be concluded that wall functions implemented in Fluent works correctly. This aspect is very important and has been discussed for years (Chen and Jiang, 1992).
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Scalar and fermionic extensions of the Standard Model

Scalar and fermionic extensions of the Standard Model

Neutrinos being electrically neutral can be either Dirac or Majorana particles. Ex- perimentally determining their nature requires measuring lepton number violating ob- servables, of which neutrinoless double-β (0νββ) decay provides—certainly—the most sensitive probe. Observing a 0νββ decay signal constitutes a demonstration that lepton number is not conserved in nature and, according to the Schechter-Valle black-box theo- rem [ 15 ], that neutrinos are Majorana particles. The non-observation, however, does not prove otherwise. The 0νββ decay rate is highly sensitive to the neutrino mass spectrum: for an inverted mass spectrum (m ν 3 < m ν 1 < m ν 2 ) there is sizeable lower limit for this rate whereas for a normal mass spectrum (m ν 1 < m ν 2 < m ν 3 ) the leptonic CP phases can conspire leading to a vanishing rate [ 129 ]. Thus, only in the case of neutrinos having an inverted spectrum definitive conclusions can be drawn from the non-observation of 0νββ. Given the absence of a 0νββ signal the two possibilities are viable. If neutrinos are assumed to be Dirac particles, the addition of fermion EW singlets to the SM content allows the construction of new renormalizable Yukawa operators. After EWSB, neutrinos as any other SM fermion acquire mass. If instead neutrinos are assumed to be of Majorana
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