Adequacy of Effective Born for electroweak effects and TauSpinner algorithms for high energy physics simulated samples

Matching and comparing the measurements of past and future experiments call for consistency checks of electroweak (EW) calculations used for their interpretation. On the other hand, new calculation schemes of the field theory can be beneficial for precision, even if they may obscure comparisons with earlier results. Over the years, concepts of Improved Born, Effective Born, as well as of effective couplings, in particular of $$\sin ^2\theta _W^{{\textit{eff}}}$$ sin 2 θ W eff mixing angle for EW interactions, have evolved. In our discussion, we use four versions of EW library for phenomenology of practically all HEP accelerator experiments over the last 30 years. We rely on the codes published and archived with the Monte Carlo program for $$e^+e^- \rightarrow f {\bar{f}} n(\gamma )$$ e + e - → f f ¯ n ( γ ) and available for the as well. re-weighs generated events for introduction of EW effects. To this end, is first invoked, and its results are stored in data file and later used. Documentation of upgrade, to version 2.1.0, and that of its new arrangement for semi-automated benchmark plots are provided. In our paper, focus is placed on the numerical results, on the different approximations introduced in Improved Born to obtain Effective Born, which is simpler for applications of strong or QED processes in pp or $$e^+e^-$$ e + e - colliders. The $$\tau $$ τ lepton polarization $$P_{\tau }$$ P τ , forward–backward asymmetry $$A_{{\textit{FB}}}$$ A FB and parton-level total cross section $$\sigma ^{{\textit{tot}}}$$ σ tot are used to monitor the size of EW effects and effective $$\sin ^2\theta _W^{{\textit{eff}}}$$ sin 2 θ W eff picture limitations for precision physics. Collected results include: (i) Effective Born approximations and $$\sin ^2\theta _W^{{\textit{eff}}}$$ sin 2 θ W eff , (ii) differences between versions of EW libraries and (iii) parametric uncertainties due to, for example, $$m_t$$ m t or $$\Delta \alpha _h^{(5)}(s)$$ Δ α h ( 5 ) ( s ) . These results can be considered as benchmarks and also allow to evaluate the adequacy of Effective Born with respect to Improved Born. Definitions are addressed too.

Flavored leptogenesis and neutrino mass with A4 symmetry

We propose a minimal A4 flavor symmetric model, assisted by Z2× Z3 symmetry, which can naturally takes care of the appropriate lepton mixing and neutrino masses via Type-I seesaw. It turns out that the framework, originated due to a specific flavor structure, favors the normal hierarchy of light neutrinos and simultaneously narrows down the range of Dirac CP violating phase. It predicts an interesting correlation between the atmospheric mixing angle and the Dirac CP phase too. While the flavor structure indicates an exact degeneracy of the right-handed neutrino masses, renormalization group running of the same from a high scale is shown to make it quasi-degenerate and a successful flavor leptogenesis takes place within the allowed parameter space obtained from neutrino phenomenology.

Reinterpreting the ATLAS bounds on heavy neutral leptons in a realistic neutrino oscillation model

Heavy neutral leptons (HNLs) are hypothetical particles, motivated in the first place by their ability to explain neutrino oscillations. Experimental searches for HNLs are typically conducted under the assumption of a single HNL mixing with a single neutrino flavor. However, the resulting exclusion limits may not directly constrain the corresponding mixing angles in realistic HNL models — those which can explain neutrino oscillations. The reinterpretation of the results of these experimental searches turns out to be a non-trivial task, that requires significant knowledge of the details of the experiment. In this work, we perform a reinterpretation of the latest ATLAS search for HNLs decaying promptly to a tri-lepton final state. We show that in a realistic model with two HNLs, the actual limits can vary by several orders of magnitude depending on the free parameters of the model. Marginalizing over the unknown model parameters leads to an exclusion limit on the total mixing angle which can be up to 3 orders of magnitude weaker than the limits reported in ref. [1]. This demonstrates that the reinterpretation of results from experimental searches is a necessary step to obtain meaningful limits on realistic models. We detail a few steps that can be taken by experimental collaborations in order to simplify the reuse of their results.

Evolution of neutrino mass-mixing parameters in matter with non-standard interactions

We explore the role of matter effect in the evolution of neutrino oscillation parameters in the presence of lepton-flavor-conserving and lepton-flavor-violating neutral-current non-standard interactions (NSI) of the neutrino. We derive simple approximate analytical expressions showing the evolution of mass-mixing parameters in matter with energy in the presence of standard interactions (SI) and SI+NSI (considering both positive and negative values of real NSI parameters). We observe that only the NSI parameters in the (2,3) block, namely εμτ and (γ − β) ≡ (εττ− εμμ) affect the modification of θ23. Though all the NSI parameters influence the evolution of θ13, εeμ and εeτ show a stronger impact at the energies relevant for DUNE. The solar mixing angle θ12 quickly approaches to ∼ 90° with increasing energy in both SI and SI+NSI cases. The change in ∆$$ {m}_{21,m}^2 $$ m 21 , m 2 is quite significant as compared to ∆$$ {m}_{31,m}^2 $$ m 31 , m 2 both in SI and SI+NSI frameworks for the energies relevant for DUNE baseline. Flipping the signs of the NSI parameters alters the way in which mass-mixing parameters run with energy. We demonstrate the utility of our approach in addressing several important features related to neutrino oscillation such as: a) unraveling interesting degeneracies between θ23 and NSI parameters, b) estimating the resonance energy in presence of NSI when θ13 in matter becomes maximal, c) figuring out the required baselines and energies to have maximal matter effect in νμ → νe transition in the presence of different NSI parameters, and d) studying the impact of NSI parameters εμτ and (γ − β) on the νμ → νμ survival probability.

Theory requirements for SM Higgs and EW precision physics at the FCC-ee

High-precision experimental measurements of the properties of the Higgs boson at $$\sim 125$$ ∼ 125 GeV as well as electroweak precision observables such as the W-boson mass or the effective weak leptonic mixing angle are expected at future $$e^+e^-$$ e + e - colliders such as the FCC-ee. This high anticipated precision has to be matched with theory predictions for the measured quantities at the same level of accuracy. We briefly summarize the status of these predictions within the standard model and of the tools that are used for their determination. We outline how the theory predictions will have to be improved in order to reach the required accuracy, and also comment on the simulation frameworks for the Higgs and EW precision program.

Heavy neutral leptons in effective field theory and the high-luminosity LHC

Heavy neutral leptons (HNLs) with masses around the electroweak scale are expected to be rather long-lived particles, as a result of the observed smallness of the active neutrino masses. In this work, we study long-lived HNLs in NRSMEFT, a Standard Model (SM) extension with singlet fermions to which we add non-renormalizable operators up to dimension-6. Operators which contain two HNLs can lead to a sizable enhancement of the production cross sections, compared to the minimal case where HNLs are produced only via their mixing with the SM neutrinos. We calculate the expected sensitivities for the ATLAS detector and the future far-detector experiments: AL3X, ANUBIS, CODEX-b, FASER, MATHUSLA, and MoEDAL-MAPP in this setup. The sensitive ranges of the HNL mass and of the active-heavy mixing angle are much larger than those in the minimal case. We study both, Dirac and Majorana, HNLs and discuss how the two cases actually differ phenomenologically, for HNL masses above roughly 100 GeV.

The Higgs potential in 2HDM extended with a real triplet scalar: A roadmap

We perform a comprehensive study of the Higgs potential of the two Higgs doublet model extended by a real triplet scalar field [Formula: see text]. This model, dubbed [Formula: see text], has a rich Higgs spectrum consisting of three CP-even Higgs [Formula: see text], one CP-odd [Formula: see text] and two pairs of charged Higgs [Formula: see text]. First, we determine the perturbative unitarity constraints and a set of nontrivial conditions for the boundedness from below (BFB). Then we derive the Veltman conditions by considering the quadratic divergencies of Higgs boson self-energies in [Formula: see text]. We find that the parameter space is severely delimited by these theoretical constraints, as well as experimental exclusion limits and Higgs signal rate measurements at LEP and LHC. Using HiggsBounds-5.3.2beta and HiggSignals-2.2.3beta public codes, an exclusion test at [Formula: see text] is then performed on the physical scalars of [Formula: see text]. Our analysis provides a clear insight on the nonstandard scalar masses, showing that the allowed ranges are strongly sensitive to the sign of mixing angle [Formula: see text], essentially when naturalness is involved. For [Formula: see text] scenario, our results place higher limits on the bounds of all scalar masses, and show that the pairs [Formula: see text] and [Formula: see text] are nearly mass degenerate varying within the intervals [Formula: see text] GeV and [Formula: see text] GeV, respectively. When [Formula: see text] turns positive, we show that consistency with theoretical constraints and current LHC data, essentially on the diphoton decay channel, favors Higgs masses varying within wide allowed ranges: [Formula: see text] GeV for [Formula: see text]; [Formula: see text] GeV for ([Formula: see text], [Formula: see text]) and [Formula: see text] GeV for ([Formula: see text], [Formula: see text]). Finally, we find that the [Formula: see text] and [Formula: see text] Higgs decay modes are generally correlated if [Formula: see text] lies within the reduced intervals [Formula: see text] and [Formula: see text] parameter is frozen around [Formula: see text] ([Formula: see text]) for [Formula: see text] ([Formula: see text]).

Mixing Behavior and Pressure Drop Analysis of Micromixer with Different Geometric Conditions

A 3-D design of and analysis of fluid flow in the micromixer with different configurations is carried out in this dissertation. The main purpose of this research is to obtain minimum mixing length as rapid mixing is essential in many of the micro-fluidic systems used in biochemistry analysis, drug delivery, sequencing, or synthesis of nucleic acids. Also effect on various parameters such as mixing behavior, volume arrow, mixing length, maximum velocity, maximum pressure, pressure drop, and velocity distribution were analyzed by changing the mixing angle between inlets. Micromixers with square cross-section rectangular mixing chamber with various types of obstacle place in fluid flow paths such as rectangular obstacles, elliptical obstacle, and circular obstacle in split and recombination manner were designed for the analysis. The micromixer has 3 inlets and 1 outlet. Water and ethanol were used as working fluids. For computational fluid dynamics analysis, COMSOL Multiphysics 5.0 is used. From various results, we have found that size, the geometry of mixing chambers and obstacles, and mixing angle effect mixing length, pressure, and velocity. With a decrease in mixing angle mixing length, pressure drop, and maximum velocity decrease i.e it gives better mixing performance. Also with an increase in the number of obstacles mixing length and maximum velocity decreases and pressure drop increases. Micromixer with mixing angle 60 degree and circular obstacles gives minimum mixing length than any other models consisting rectangular or elliptical obstacle and mixing angle greater than 60 degrees.