arXiv subjects

O. Sumensari

Publications and source records attributed to O. Sumensari.

8 recordsLinked to original sources

arXiv2026

Neutrinoless Double-Beta Decays from Operator Mixing

We perform a complete one-loop Renormalization Group (RG) analysis of neutrinoless double-beta decays within the Standard Model Effective Field Theory (SMEFT). Although several effective operators do not contribute to these processes at tree level, we show that they can generate sizable contributions through operator mixing. By accounting for the full one-loop RG evolution within the SMEFT, we find that the resulting constraints provide the most stringent bounds on numerous dimension-seven operators, improving upon limits derived from meson decays. We also highlight the importance of contributions beyond the first leading logarithm, which can provide the leading effects for specific operators and flavor combinations.

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arXiv2026

Interpreting the results on exclusive $c\rightarrow s\mu\nu$ modes

We examine the $q^2$-binned distributions of the $D\to K\mu\nu$ decay rate and of the corresponding forward-backward asymmetry which were recently measured by BESIII, showing a mild deviation from the Standard Model predictions. We point out that the proposed solution to remedy the discrepancy by turning on a complex-valued New Physics coupling is in tension with the constraints deduced from the LHC bounds on the high-$p_T$ tail of the relevant Drell-Yan process. We then show that there are several plausible scenarios that are compatible with both the measured low-energy and high-energy constraints but the selected couplings appear to be too small to be observed in the measurements of integrated observables, except for possibly the $q^2$-binned distribution of the angular observables relevant to $D_s\to \phi (\to KK) \mu\nu$ or $\Lambda_c\to \Lambda (\to p \pi) \mu\nu$ modes.

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arXiv2025

Flavor constraints from $pp\to Vh$ and $pp\to VW$ at the LHC

We investigate the potential of associated Higgs $pp\to Vh$ and diboson production $pp\to VW$ channels at the LHC (with $V=W,Z$) to constrain flavor-physics operators. Within a general Effective Field Theory (EFT) framework, we derive the helicity amplitudes for these processes at high energies and identify the leading contributions from dimension-six operators involving different quark flavors. Using available LHC data, we show that these processes are sensitive to non-trivial flavor structures and provide complementary constraints to those from low-energy observables. We illustrate this synergy through an explicit comparison between our LHC bounds with electroweak precision data, and with flavor limits derived from charged-current pion and kaon decays. In particular, we show that our HL-LHC projections can probe viable EFT scenarios proposed to accommodate the discrepancies in the extraction of the Cabibbo angle.

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arXiv2024

Correlating $0\nu\beta\beta$ decays and flavor observables in leptoquark models

In this paper, we investigate minimal scalar leptoquark models that dynamically generate neutrino Majorana masses at the one-loop level and examine their implications for low-energy processes. We show that these models can produce viable neutrino masses, consistent with neutrino oscillation and cosmological data. By using leptoquark couplings fixed by neutrino data, we predict additional contributions to neutrinoless double-beta decays ($0\nu\beta\beta$), which are chirality enhanced and compete with the standard contributions from the Majorana masses. Our analysis demonstrates that these effects are sizable for leptoquark masses as large as $\mathcal{O}(300~\mathrm{TeV})$, potentially increasing or decreasing the $0\nu\beta\beta$ half-life, and creating an ambiguity between the normal and inverted mass ordering scenarios. Furthermore, we explore the correlation between $0\nu\beta\beta$ and flavor observables, such as kaon decays and $\mu\to e$ conversion in nuclei, emphasizing that the latter is complementary to $0\nu\beta\beta$ decays.

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arXiv2023

Lepton Flavor Violation in Semileptonic Observables

In this paper, we perform a comprehensive study of Lepton Flavor Violation (LFV) in semileptonic transitions in the framework of an Effective Field Theory with general flavor structure. We account for the Renormalization Group Equations (RGEs), which induce non-trivial correlations between the different types of LFV processes. In particular, we show that these loop effects are needed to improve the bounds on several coefficients that are not efficiently constrained at tree level. For illustration, we consider a few concrete scenarios, with predominant couplings to third-generation quarks, and we explore the correlations between the various tree- and loop-level constraints on these models. As a by-product, we also provide expressions for several semileptonic LFV meson decays by using the latest determinations of the relevant hadronic form factors on the lattice.

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arXiv2020

Flavor constraints on electroweak ALP couplings

We explore the signals of axion-like particles (ALPs) in flavor-changing neutral current (FCNC) processes. The most general effective linear Lagrangian for ALP couplings to the electroweak bosonic sector is considered, and its contribution to FCNC decays is computed up to one-loop order. The interplay between the different couplings opens new territory for experimental exploration, as analyzed here in the ALP mass range $0<m_a \lesssim 5$ GeV. When kinematically allowed, $K\to πν\barν$ decays provide the most stringent constraints for channels with invisible final states, while $B$-meson decays are more constraining for visible decay channels, such as displaced vertices in $B\to K^{(\ast)} μ^+ μ^-$ data. The complementarity with collider constraints is discussed as well.

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arXiv2019

Revisiting the production of ALPs at B-factories

In this paper, the production of Axion-Like Particles (ALPs) at $B$-factories via the process $e^+e^- \to γa$ is revisited. To this purpose, the relevant cross-section is computed via an effective Lagrangian with simultaneous ALP couplings to $b$-quarks and photons. The interplay between resonant and non-resonant contributions is shown to be relevant for experiments operating at $\sqrt{s}=m_{Υ(nS)}$, with $n=1,2,3$, while the non-resonant one dominates at $Υ(4S)$. These effects imply that the experimental searches performed at different quarkonia resonances are sensitive to complementary combinations of ALP couplings. To illustrate these results, constraints from existing BaBar and Belle data on ALPs decaying into invisible final states are derived, and the prospects for the Belle-II experiment are discussed.

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arXiv2015

On the Viability of Minimal Neutrinophilic Two-Higgs-Doublet Models

We study the constraints that electroweak precision data can impose, after the discovery of the Higgs boson by the LHC, on neutrinophilic two-Higgs-doublet models which comprise one extra $SU(2)\times U(1)$ doublet and a new symmetry, namely a spontaneously broken $\mathbb{Z}_2$ or a softly broken global $U(1)$. In these models the extra Higgs doublet, via its very small vacuum expectation value, is the sole responsible for neutrino masses. We find that the model with a $\mathbb{Z}_2$ symmetry is basically ruled out by electroweak precision data, even if the model is slightly extended to include extra right-handed neutrinos, due to the presence of a very light scalar. While the other model is still perfectly viable, the parameter space is considerably constrained by current data, specially by the $T$ parameter. In particular, the new charged and neutral scalars must have very similar masses.

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