Possible non-decoupling effects of heavy Higgs bosons in e+ e- -> W+ W- within THDM

We discuss the origin of the nondecoupling effects of the heavy Higgs bosons within the two Higgs doublet extension (THDM) of the Standard Model (SM) and illustrate it by means of the one-loop calculation of the differential cross-sections of the process e+ e- -> W+ W- in both the decoupling and the non-decoupling regimes. We argue that there are many regions in the THDM parametric space in which the THDM and SM predictions differ by several percents and such effects could, at least in principle, be testable at the future experimental facilities.Comment: 8 pages, 2 figures; to appear soon in EPJC. v2 - several minor corrections (typos), references adde

On CP Violation in Minimal Renormalizable SUSY SO(10) and Beyond

We investigate the role of CP phases within the renormalizable SUSY SO(10) GUT with one 10_H, one 126bar_H one 126_H and one 210_H Higgs representations and type II seesaw dominating the neutrino mass matrix. This framework is non trivially predictive in the fermionic sector and connects in a natural way the GUT unification of b and tau Yukawa couplings with the bi-large mixing scenario for neutrinos. On the other hand, existing numerical analysis claim that consistency with quark and charged lepton data prevents the minimal setup from reproducing the observed CP violation via the Cabibbo-Kobayashi-Maskawa (CKM) matrix. We re-examine the issue and find by inspection of the fermion mass sum rules and a detailed numerical scan that, even though the CKM phase takes preferentially values in the second quadrant, the agreement of the minimal model with the data is actually obtained in a non negligible fraction of the parameter space. We then consider a recently proposed renormalizable extension of the minimal model, obtained by adding one chiral 120-dimensional Higgs supermultiplet. We show that within such a setup the CKM phase falls naturally in the observed range. We emphazise the robust predictivity of both models here considered for neutrino parameters that are in the reach of ongoing and future experiments.Comment: 9 pages, 6 figures. Two refs added, discussion expanded. To appear on Phys. Rev.

Renormalization group running of neutrino parameters in the inverse seesaw model

We perform a detailed study of the renormalization group equations in the inverse seesaw model. Especially, we derive compact analytical formulas for the running of the neutrino parameters in the standard model and the minimal supersymmetric standard model, and illustrate that, due to large Yukawa coupling corrections, significant running effects on the leptonic mixing angles can be naturally obtained in the proximity of the electroweak scale, perhaps even within the reach of the LHC. In general, if the mass spectrum of the light neutrinos is nearly degenerate, the running effects are enhanced to experimentally accessible levels, well suitable for the investigation of the underlying dynamics behind the neutrino mass generation and the lepton flavor structure. In addition, the effects of the seesaw thresholds are discussed, and a brief comparison to other seesaw models is carried out.Comment: 30 pages, 7 figures. Final version published in Phys. Rev. D. v3: Typo in Eq. (33) correcte

A unified leptoquark model confronted with lepton non-universality in B-meson decays

The anomalies in the B-meson sector, in particular RK(⁎) and RD(⁎), are often interpreted as hints for physics beyond the Standard Model. To this end, leptoquarks or a heavy Z′ represent the most popular SM extensions which can explain the observations. However, adding these fields by hand is not very satisfactory as it does not address the big questions like a possible embedding into a unified gauge theory. On the other hand, light leptoquarks within a unified framework are challenging due to additional constraints such as lepton flavor violation. The existing accounts typically deal with this issue by providing estimates on the relevant couplings. In this letter we consider a complete model based on the SU(4)C⊗SU(2)L⊗U(1)R gauge symmetry, a subgroup of SO(10), featuring both scalar and vector leptoquarks. We demonstrate that this setup has, in principle, all the potential to accommodate RK(⁎) and RD(⁎) while respecting bounds from other sectors usually checked in this context. However, it turns out that KL→e±μ∓ severely constraints not only the vector but also the scalar leptoquarks and, consequently, also the room for any sizeable deviations of RK(⁎) from 1. We briefly comment on the options for extending the model in order to conform this constraint. Moreover, we present a simple criterion for all-orders proton stability within this class of models

Soft masses in SUSY SO(10) GUTs with low intermediate scales

The specific shape of the squark, slepton and gaugino mass spectra, if measured with suficient accuracy, can provide invaluable information not only about the dynamics underpinning their origin at some very high scale such as the unification scale MG, but also about the intermediate scale physics encountered throughout their RGE evolution down to the energy scale accessible for the LHC. In this work, we study general features of the TeV scale soft SUSY breaking parameters stemming from a generic mSugra configuration within certain classes of SUSY SO(10) GUTs with different intermediate symmetries below MG. We show that particular combinations of soft masses show characteristic deviations from the mSugra limit in different models and thus, potentially, allow to distinguish between these, even if the new intermediate scales are outside the energy range probed at accelerators. We also compare our results to those obtained for the three minimal seesaw models with mSugra boundary conditions and discuss the main differences between those and our SO(10) based models.Comment: 18 pages, 12 figures, 5 table

Non-Standard Neutrino Interactions from a Triplet Seesaw Model

We investigate non-standard neutrino interactions (NSIs) in the triplet seesaw model featuring non-trivial correlations between NSI parameters and neutrino masses and mixing parameters. We show that sizable NSIs can be generated as a consequence of a nearly degenerate neutrino mass spectrum. Thus, these NSIs could lead to quite significant signals of lepton flavor violating decays such as \mu^- \to e^- \nu_e anti\nu_\mu and \mu^+ \to e^+ anti\nu_e \nu_\mu at a future neutrino factory, effects adding to the uncertainty in determination of the Earth matter density profile, as well as characteristic patterns of the doubly charged Higgs decays observable at the Large Hadron Collider.Comment: 4 pages, 3 figures and 1 table; v2: minor corrections, Sect. IV revise

Non-standard antineutrino interactions at Daya Bay

We study the prospects of pinning down the effects of non-standard antineutrino interactions in the source and in the detector at the Daya Bay neutrino facility. It is well known that if the non-standard interactions in the detection process are of the same type as those in the production, their net effect can be subsumed into a mere shift in the measured value of the leptonic mixing angle theta_13. Relaxing this assumption, the ratio of the antineutrino spectra measured by the Daya Bay far and near detectors is distorted in a characteristic way, and good fits based on the standard oscillation hypothesis are no longer viable. We show that, under certain conditions, three years of Daya Bay running can be sufficient to provide a clear hint of non-standard neutrino physics.Comment: 31 pages, 12 figures; a brief discussion of systematics added in v2, published versio