New Physics Hints from Flavour

Abstract

This Thesis presents my personal contributions to two distinct fields, namely the recent experimental anomalies in B-meson decays, and the longstanding quest for a theoretical explanation of lepton masses and mixings, under a unifying umbrella: Flavour Physics. The modern view of the Standard Model as an effective theory is motivated, and the dual role of flavour, as a probe of New Physics effects on one side, and as a piece of the puzzle itself on the other, is emphasized. By jointly discussing two physics cases of different nature, I attempt to offer a broader perspective on the current status of Beyond Standard Model searches. The discussion begins with a preliminary review of Standard Model Effective Field Theories, in which some utility results in theory matching are presented. The focus then moves to B-meson decay anomalies: after introducing Lepton Flavour Universality, we discuss the phenomenology of a specific Standard Model extension by scalar leptoquarks, and also present the Effective Field Theory framework of Rank-One Flavor Violation, providing a less detailed but broader picture for the case of neutral-current anomalies. Finally, we tackle the Standard Model flavour puzzle, describing an attempt to address charged lepton mass hierarchies in the framework of supersymmetric modular invariant models of lepton flavour.

arXiv commentPhD Thesis

References in corpus (86)

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• Dimension-Six Terms in the Standard Model Lagrangian
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• Measurement of the Negative Muon Anomalous Magnetic Moment to 0.7 ppm
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• Measurement of an Excess of B -> D(*) Tau Nu Decays and Implications for Charged Higgs Bosons
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• Measurement of the branching ratio of $\bar{B}\to D^{(\ast )}{\tau }^{-}{\bar{\nu }}_{\tau }$ relative to $\bar{B}\to D^{(\ast )}{\ell }^{-}{\bar{\nu }}_{\ell }$ decays with hadronic tagging at Belle
• Renormalization Group Evolution of the Standard Model Dimension Six Operators I: Formalism and lambda Dependence
• Searches for Lepton Flavor Violation in the Decays tau -> e gamma and tau -> mu gamma
• Electroweak symmetry breaking after LEP1 and LEP2
• Measurement of form-factor independent observables in the decay $B^0\to K^{\ast 0}{\mu }^{+}{\mu }^{-}$
• Model-independent constraints on Delta F=2 operators and the scale of New Physics
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• Search for Lepton Flavor Violating Tau Decays into Three Leptons with 719 Million Produced Tau+Tau- Pairs
• On the Standard Model predictions for $R_K$ and $R_{K^{\ast }}$
• Dressing L_mu - L_tau in Color
• The Composite Nambu-Goldstone Higgs
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• Simultaneous Explanation of $R(D^{(\ast )})$ and $b\to s{\mu }^{+}{\mu }^{-}$: The Last Scalar Leptoquarks Standing
• Anomalies in $B$-decays and $U(2)$ flavour symmetry
• A three-site gauge model for flavor hierarchies and flavor anomalies
• Confronting lepton flavor universality violation in B decays with high-$p_T$ tau lepton searches at LHC
• U(2) and Minimal Flavour Violation in Supersymmetry
• Neutrino Mass Anarchy
• Simultaneous Explanation of the $R_K$ and $R(D^{(\ast )})$ Puzzles
• Lepton Flavor Violation in B Decays?
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• Gauge leptoquark as the origin of B-physics anomalies
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• $R_K$ and $R_{K^{\ast }}$ beyond the Standard Model
• Modular $A_4$ invariance and neutrino mixing
• $R_{D^{(\ast )}}$ anomaly: A possible hint for natural supersymmetry with $R$-parity violation
• Low-energy effective field theory below the electroweak scale: matching at one loop
• Search for $\mathbf{B}\to \mathbf{h\nu }\bar{\mathbf{\nu }}$ decays with semileptonic tagging at Belle
• New Physics in $b\to s{\mu }^{+}{\mu }^{-}$ after the Measurement of $R_{K^{\ast }}$
• Maximal Flavour Violation: a Cabibbo mechanism for leptoquarks
• CKM benchmarks for electron EDM experiments
• Unification and Fermion Mass Structure
• Search for the Electric Dipole Moment of the tau Lepton
• The Mono-Tau Menace: From $B$ Decays to High-$p_T$ Tails
• CoDEx: Wilson coefficient calculator connecting SMEFT to UV theory
• Measurement of the decay $B\to D\ell {\nu }_{\ell }$ in fully reconstructed events and determination of the Cabibbo-Kobayashi-Maskawa matrix element $|V_{cb}|$
• Double Cover of Modular $S_4$ for Flavour Model Building
• A modified naturalness principle and its experimental tests
• A note on the predictions of models with modular flavor symmetries
• Statistical Test of Anarchy
• Combined explanations of B-physics anomalies: the sterile neutrino solution
• Matching scalar leptoquarks to the SMEFT at one loop
• Is there a Landau Pole Problem in QED?
• Eclectic Flavor Groups
• Low-energy phenomenology of scalar leptoquarks at one-loop accuracy
• Lessons from eclectic flavor symmetries
• Complete One-Loop Matching for a Singlet Scalar in the Standard Model EFT
• The role of the $S_3$ GUT leptoquark in flavor universality and collider searches
• Muon $g-2$ and scalar leptoquark mixing
• MatchingTools: a Python library for symbolic effective field theory calculations
• KL to pi0 e+ e- and KL to pi0 mu+ mu- : A binary star on the stage of flavor physics
• Type II seesaw models with modular $A_4$ symmetry
• Search for the decays $B_s^0\to {\tau }^{+}{\tau }^{-}$ and $B^0\to {\tau }^{+}{\tau }^{-}$
• Improved Bhabha cross section at LEP and the number of light neutrino species
• $CP$ violation in modular invariant flavor models
• Lepton flavor model with modular $A_4$ symmetry in large volume limit
• $U(1{)}_{B_3-3L_{\mu }}$ gauge symmetry as a simple description of $b\to s$ anomalies
• $B$ decay anomalies and dark matter from vectorlike confinement
• A search for the decay modes B+/- to h+/- tau l
• First measurement of the differential branching fraction and $CP$ asymmetry of the $B^{\pm }\to {\pi }^{\pm }{\mu }^{+}{\mu }^{-}$ decay
• Search for $B^{+}\to K^{+}{\tau }^{+}{\tau }^{-}$ at the BaBar experiment
• Search for Lepton-Flavor-Violating tau Decays into a Lepton and a Vector Meson
• Half-integral weight modular forms and application to neutrino mass models
• Towards unification of quark and lepton flavors in $A_4$ modular invariance
• Dirac neutrino mass models with a modular $S_4^{}$ symmetry
• Non-Renormalization Theorems in Non-Renormalizable Theories
• No Effect of Majorana Phases in Neutrino Oscillations
• Effective Field Theory of Integrating out Sfermions in the MSSM: Complete One-Loop Analysis
• Flavour from accidental symmetries
• $R(K^{(\ast )})$ from dark matter exchange
• Improved limit on the branching fraction of the rare decay $K_S^0\to {\mu }^{+}{\mu }^{-}$
• Dark Matter in the Standard Model?