Apesar do grande sucesso alcancado pela teoria do modelo padrao baseada nas simetrias SUs(3)? SUs... more Apesar do grande sucesso alcancado pela teoria do modelo padrao baseada nas simetrias SUs(3)? SUs(2)? U(1), ainda existem alguns desafios a serem conquistados. Uma maneira direta de resolver os problemas e interpretar o modelo padrao (SM) como um modelo efetivo cuja validade chega ate uma escala de energia E ? ?, na qual ele deixa de ser valido. Suspeita-se de que ? ~ TeV, e podera ser observada nova fisica com as analises do Large Hadron Collider (LHC). No sentido de teoria efetiva do SM, e possivel explicar a origem da oscilacao de neutrinos [2] via mecanismo de Higgs, combinado com o modelo See-saw[1]. Esse mecanismo produz um operador 5-dimensional renormalizavel que gera os ângulos de mistura dos neutrinos. Esse trabalho faz um estudo sobre a evolucao dos ângulos de mistura dos neutrinos com a energia, via equacoes do grupo de renormalizacao. Comparando o modelo padrao com sua possivel extensao, o modelo supersimetrico e modelos com uma dimensao espacial extra. A evolucao dos ângulos de mistura e bem sutil mesmo para altas energias na ordem de 14TeV, ~ 2:5% para os modelos padrao e supersimetrico, com evolucao com a escala na forma logaritmica e, um pouco mais acentuada, ~ 15% para o modelos com dimensoes extras, cujo resultado esperado pela dependencia quadratica na escala de energia problema. A analise foi feita para alguns valores nos raios das dimensoes extras, e foi visto, como o esperado, que quanto menor o raio, menor e a mudanca visivel a baixas energias. Tais resultados podem ajudar na selecao de modelos, entretanto a variacao no ângulo de mistura nao e observavel fora dos erros experimentais atuais- de medicoes ja realizadas sobre oscilacao de neutrinos. A variacao entre os modelos e, portanto, leve, de forma que nao e possivel verifica-la com os dados atuais Abstract
The recent XENON1T excess can be explained by the solar active-sterile neutrino conversion with b... more The recent XENON1T excess can be explained by the solar active-sterile neutrino conversion with bound electrons via light mediator. Nevertheless, the atomic effects are usually omitted in the solar neutrino explanations. We systematically establish a second quantization formalism for both bound and ionized electrons to account for the atomic effects. This formalism is of great generality to incorporate various interactions for both neutrino and dark matter scatterings. Our calculation shows that the change in the cross section due to atomic effects can have important impact on the differential cross section. It is necessary to include atomic effects in the low-energy electron recoil signal at dark matter direct detection experiments even for energetic solar neutrinos. With the best-fit values to the XENON1T data, we also project the event rate at PandaX-4T, XENONnT, and LZ experiments.
We explore the possibility of using the recently proposed THEIA detector to measure the $\bar ν_μ... more We explore the possibility of using the recently proposed THEIA detector to measure the $\bar ν_μ\rightarrow \bar ν_e$ oscillation with neutrinos from a muon decay at rest ($μ$DAR) source to improve the leptonic CP phase measurement. Due to its intrinsic low-energy beam, this $μ$THEIA configuration ($μ$DAR neutrinos at THEIA) is only sensitive to the genuine leptonic CP phase $δ_D$ and not contaminated by the matter effect. With detailed study of neutrino energy reconstruction and backgrounds at the THEIA detector, we find that the combination with the high-energy DUNE can significantly reduce the CP uncertainty, especially around the maximal CP violation cases $δ_D = \pm 90^\circ$. Both the $μ$THEIA-25 with 17kt and $μ$THEIA-100 with 70kt fiducial volumes are considered. For DUNE + $μ$THEIA-100, the CP uncertainty can be better than $8^\circ$.
arXiv: High Energy Physics - Phenomenology, Nov 21, 2019
The mixing of three active neutrino flavors is parameterized by the unitary PMNS matrix. If there... more The mixing of three active neutrino flavors is parameterized by the unitary PMNS matrix. If there are more than three neutrino flavors and if the extra generations are heavy iso-singlets, the effective 3 × 3 mixing matrix for the three active neutrinos will be non-unitary. We have analyzed the latest T2K and NOνA data with the hypothesis of non-unitary mixing of the active neutrinos. We found that the 2019 NOνA data slightly (at ∼ 1 σ C.L.) prefer the non-unitary mixing over unitary mixing. In fact, allowing the non-unitary mixing brings the NOνA best-fit point in the sin 2 θ 23 − δ CP plane closer to the T2K best-fit point. The 2019 T2K data, on the other hand, cannot rule out any of the two mixing schemes. A combined analysis of the NOνA and T2K 2019 data prefers the non-unitary mixing at 1 σ C.L.. We derive constraints on the non-unitary mixing parameters using the best-fit to the combined NOνA and T2K data. These constraints are weaker than previously found. The latest 2020 data from both the experiments prefer non-unitarity over unitary mixing at 1 σ C.L. The combined analysis prefers non-unitarity at 2 σ C.L. The stronger tension, which exists between the latest 2020 data of the two experiments, also gets reduced with non-unitary analysis.
We show that the minimal 3-3-1 model cannot accommodate the neutrino masses at tree level using p... more We show that the minimal 3-3-1 model cannot accommodate the neutrino masses at tree level using present experimental data. Nevertheless, a modified Zee and the Zee-Babu mechanisms for generating neutrino masses at 1-loop and 2-loop, respectively, are automatically implemented in the minimal 3-3-1 model, without introducing new degrees of freedom to the model. We also present a systematic method for finding solutions to the leptonic sector masses and mixing. As a case study, we accommodate the charged and neutral leptons masses and the PMNS matrix in the 1-loop modified Zee mechanism contained in the minimal 3-3-1 model.
We found an analytical solution for the neutrino mass matrix in the most general case of the Zee ... more We found an analytical solution for the neutrino mass matrix in the most general case of the Zee model. Using the recent data on the neutrino parameters besides generating neutrino masses at 1-loop level we fit also the masses of the charged leptons and the leptonic mixing matrix. We also show in what conditions the model is not compatible with neutrino data.
We review the current status of neutrino oscillation experiments, mainly focussed on T2(H)K, NO$\... more We review the current status of neutrino oscillation experiments, mainly focussed on T2(H)K, NO$\nu$A and DUNE. Their capability to probe high energy physics is found in the precision measurement of the CP phase and $\theta_{23}$. In general, neutrino mass models predicts correlations among the mixing angles that can be used to scan and shrink down its parameter space. We updated previous analysis and presents a list of models that contain such structure.
The effects of Lorentz Invariance Violation(LIV) operators up to dimension 6 in long baseline neu... more The effects of Lorentz Invariance Violation(LIV) operators up to dimension 6 in long baseline neutrino experiments are discussed, in specific for DUNE and T2K. A phenomenological Lagrangian is proposed followed by a computation of the effective Hamiltonian of neutrino propagation in matter for mass eigenstates. It is shown that the simplest dimension 4 Lorentz violation parameter can decrease DUNE sensitivity to neutrino mass hierarchy. Also, a $\chi^2$ analysis is performed to obtain the expected long-baseline constraints to the LIV operators up to dimension 6.
The mixing of three active neutrino flavors is parameterized by the unitary PMNS matrix. If there... more The mixing of three active neutrino flavors is parameterized by the unitary PMNS matrix. If there are more than three neutrino flavors and if the extra generations are heavy iso-singlets, the effective $$3\times 3$$ 3 × 3 mixing matrix for the three active neutrinos will be non-unitary. We have analyzed the latest T2K and NO$$\nu $$ ν A data with the hypothesis of non-unitary mixing of the active neutrinos. We found that the 2019 NO$$\nu $$ ν A data slightly (at $$\sim 1\, \sigma $$ ∼ 1 σ CL) prefer the non-unitary mixing over unitary mixing. In fact, allowing the non-unitary mixing brings the NO$$\nu $$ ν A best-fit point in the $$\sin ^2{\theta _{23}}-\delta _{\mathrm {CP}}$$ sin 2 θ 23 - δ CP plane closer to the T2K best-fit point. The 2019 T2K data, on the other hand, cannot rule out any of the two mixing schemes. A combined analysis of the NO$$\nu $$ ν A and T2K 2019 data prefers the non-unitary mixing at $$1\, \sigma $$ 1 σ CL. We derive constraints on the non-unitary mixing p...
We propose a new scenario of using the dark axion portal at one-loop level to explain the recentl... more We propose a new scenario of using the dark axion portal at one-loop level to explain the recently observed muon anomalous magnetic moment by the Fermilab Muon g-2 experiment. Both axion/axion-like particle (ALP) and dark photon are involved in the same vertex with photon. Although ALP or dark photon alone cannot explain muon $$g-2$$ g - 2 , since the former provides only negative contribution while the latter has very much constrained parameter space, dark axion portal can save the situation and significantly extend the allowed parameter space. The observed muon anomalous magnetic moment provides a robust probe of the dark axion portal scenario.
The recent Xenon1T excess can be explained by solar neutrino scattering with electron via a light... more The recent Xenon1T excess can be explained by solar neutrino scattering with electron via a light mediator, either scalar or vector, in addition to many other explanations from the dark sector. Since only the recoil electron is observable, a keV sterile neutrino instead of an active neutrino can appear in the final state. The sterile neutrino allows pseudoscalar mediator to explain the Xenon1T excess which was thought impossible. In addition, nonzero recoil energy lower bound arises from the sterile neutrino mass, which can be used to testify if the sterile neutrino is massive or not. We also briefly discuss the case of sterile neutrino final state with light Z mediator.
The conventional derivation of neutrino oscillation treats neutrino mass eigenstate as plane wave... more The conventional derivation of neutrino oscillation treats neutrino mass eigenstate as plane wave with an overall evolution phase. Nevertheless, due to the intrinsic parity-violating nature of weak interactions, only the left-chiral neutrino can be produced as initial condition. On the other hand, the neutrino mass term connects the left-chiral component to the right-chiral one and unavoidably leads to generation of the later through oscillation. This chiral oscillation has significant consequences on the detection of the cosmological relic neutrinos. The event rate is reduced by a factor of 2 than the conventional prediction.
We performed a simulation on the DUNE experiment to probe the capability of future neutrino long-... more We performed a simulation on the DUNE experiment to probe the capability of future neutrino long-baseline experiments' ability to constrain the parameter space of high-energy models by using the correlation between the atmospheric and reactor mixing angles. As an example, we took the Tetrahedral Flavour Symmetry model, which predicts a strong relation between the non-zero value of θ13 and deviation of θ23 from the maximality. We show that in this case, the model can realistically be excluded in more than 3σ for most of the parameter space. We also study the octant degeneracy at DUNE and this impact on the sensitivity of such models.
We study the capabilities of the short baseline neutrino program at Fermilab to probe the unitari... more We study the capabilities of the short baseline neutrino program at Fermilab to probe the unitarity of the lepton mixing matrix. We find the sensitivity to be slightly better than the current one. Motivated by the future DUNE experiment, we have also analyzed the potential of an extra liquid Argon near detector in the LBNF beamline. Adding such a near detector to the DUNE setup will substantially improve the current sensitivity on non-unitarity. This would help to remove CP degeneracies due to the new complex phase present in the neutrino mixing matrix. We also study the sensitivity of our proposed setup to light sterile neutrinos for various configurations.
Here we study the pattern of neutrino oscillations emerging from a previously proposed warped mod... more Here we study the pattern of neutrino oscillations emerging from a previously proposed warped model construction incorporating ∆(27) flavor symmetry [1]. In addition to a complete description of fermion masses, the model predicts the lepton mixing matrix in terms of two parameters. The good measurement of θ 13 makes these two parameters nearly proportional, leading to an approximate one-parameter description of neutrino oscillations. There is a sharp fourfold degenerate correlation between δ CP and the atmospheric mixing angle θ 23 , so that maximal θ 23 also implies maximal leptonic CP violation. The predicted electron neutrino and anti-neutrino appearance probabilities indicate that the model should be tested at the T2K, NOνA and DUNE long baseline oscillation experiments.
We review the current status of neutrino oscillation experiments, mainly focusing on T2(H)K, NOνA... more We review the current status of neutrino oscillation experiments, mainly focusing on T2(H)K, NOνA, and DUNE. Their capability to probe high energy physics is found in the precision measurement of the CP phase and θ23. In general, neutrino mass models predict correlations among the mixing angles that can be used to scan and shrink their parameter space. We updated previous analysis and presented a list of models that contain such structure.
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Papers by Pedro Pasquini