The Large Hadron Collider (LHC) at CERN is currently our most powerful tool for exploring the fundamental laws of nature at the energy frontier. Beyond its role as a discovery machine, the LHC has also demonstrated remarkable capability as a precision machine. In this presentation, I will highlight key results from precision measurements of Standard Model processes and searches for new...
Deep-learning methods have given us new tools for finding outliers in datasets, and opens up new opportunities for new-physics search strategies based on these anomaly-detection tools. In this talk I will discuss Normalised AutoEncoders, and how self-supervised learning can be used to find effective sets of observables for the analyses.
After more than a decade of operations, the LHC is entering into a new era of precision physics. This evolution demands the refinement of our tools to uncover New Physics (NP), leveraging the statistical advantages of unprecedented data volume. Assuming NP lies beyond the current energy reach, the Standard Model Effective Field Theory (SMEFT) emerges as a powerful framework for an indirect...
The Standard Model and Higgs Effective Field Theories (SMEFT and HEFT) are well-established theoretical frameworks for the parameterization of potential new physics signals from nearly decoupled BSM sectors. The two EFTs differ in the scalar field content and - most notably - in the power counting, i.e. the way they organize BSM effects into a series expansion. While in SMEFT the power...
While the Higgs boson’s couplings to massive gauge bosons and third-generation fermions align with Standard Model predictions, those to the light quarks and the electron remain experimentally elusive. In this talk, I will classify and investigate simplified UV models that can significantly enhance Yukawa couplings of light fermions. These models generate operators in Standard Model Effective...
Some effects induced by SMEFT operators at one-loop have been fully computed, in particular, the renormalization of divergences by physical operators in single insertions of dimension-six operators. Important non-logarithmically enhanced contributions remain to be calculated. We discuss dimensional regularization in the Breitenlohner-Maison 't Hooft-Veltman scheme. The goal here consists of...
A selection of recent results from the Belle II and LHCb experiments are presented.
Non-leptonic B decays are great probes of CP violation and the most precise probes for the CKM angles. These determinations use golden modes, data and/or isospin symmetry to reduce the theoretical uncertainties, as non-leptonic decays remain notoriously challenging to calculate from QCD principles. At the same time, there is a wealth of experimental data that can be exploited to obtain...
We consider various modes based on $c\to s e \nu$ in order to see what precision of LQCD results for relevant hadronic matrix elements and of the experimental data are needed to probe the effects of physics beyond the SM.
$c\to s e \nu$ case is good for many reasons, including the fact that all of its couplings to physics BSM are strongly constrained by the measured high-pT tails of the...
The non-observation of baryon number violation suggests that the scale of baryon-number violating interactions at zero temperature is comparable to the GUT scale. However, the pertinent measurements involve hadrons made of the first-generation quarks, such as protons and neutrons. One may entertain the idea that new flavor physics breaks baryon number at a much lower scale, but only in the...
In this talk, we discuss inclusive decays of heavy hadrons containing a b-quark, specifically focusing on Lambda-b baryons within the framework of the heavy quark expansion (HQE). By utilising recent lattice QCD calculations of exclusive form factors, we aim to identify the regions in the plane of non-perturbative parameters—namely the kinetic and Darwin terms—that are consistent with small...
A new run on the Z-pole producing more than 1 trillion Z bosons (Tera-Z) such as proposed at FCC-ee will have indirect sensitivity to heavy new physics up to the tens of TeV scale via higher-order loop contributions to electroweak precision observables. I discuss how new physics with the right flavor structure to lie within reach of future colliders populates a specific subset of SMEFT...
A fundamental part of event generation, hadronization is currently simulated with the help of fine-tuned empirical models. Motivated by the difficulties of these models, in this talk I'll present MLHAD: a proposed alternative where the empirical model is replaced by a surrogate Machine Learning-based model to be ultimately data-trainable. I'll detail the current stage of development and...
Despite extensive efforts, the fundamental nature of Dark Matter remains unknown. Collider searches provide a unique window into potential Dark Matter interactions, particularly through the "monojet" channel—characterized by a small number of energetic jets recoiling against significant missing transverse momentum in a lepton-free final state. Traditional analysis methods often struggle to...
I will explore measurements at the LHC and future colliders that are sensitive to the relative sign of the coupling between the Higgs and the W and the Higgs and the Z. The relative sign of these couplings can be opposite that of the Standard Model in models with Higgs multiplets larger than doublet. Finally, I will explain the caveats in recent experimental searches that claim to measure the...
The theoretical predictions for the $D-\bar{D}$ mixing parameters fall significantly short of experimental measurements, with discrepancies spanning several orders of magnitude. This divergence is largely attributed to the Glashow–Iliopoulos–Maiani (GIM) mechanism, which suppresses leading-order contributions. However, higher-order corrections and nonperturbative effects have the potential to...
In this talk, I will review the bounds that can be inferred on New Physics couplings to heavy sterile neutrinos $N$ from the recent measurements performed by the Belle collaboration of the angular analysis of $B \to D^*\ell\nu$ decays, with $\ell=e,\mu$. Indeed, a sterile neutrino N may lead to competing $B \to D^*\ell N$ decays and Belle might have measured an incoherent sum of these two...
For several years, many long-standing anomalies in rare $b \to s\ell \bar\ell$ decays have raised questions about possible hints of physics beyond the Standard Model (SM). These anomalies appear not only in branching ratios of $B\to K$, $B\to K^*$, and $B_s\to \phi$ in both high- and low-$q^2$ regions (with $q^2$ the invariant mass of the dilepton pair), but also in angular observables such as...
Any study of leptoquark (LQ) searches at colliders must include constraints on the parameter space from low-energy physics. I show that radiative corrections to the leptoquark-fermion couplings can be large and have a particularly simple pattern: If only one LQ species is present, the radiative corrections are universal and deplete all LQ-fermion couplings probed at high energies (in on-shell...
We derive a generalisation of the Boyd-Grinstein-Lebed (BGL) parametrization. Most form factors (FFs) in $b$-hadron decays exhibit additional branch cuts --- namely subthreshold and anomalous branch cuts --- beyond the "standard'' unitarity cut. These additional cuts cannot be adequately accounted for by the BGL parametrization. For instance, these cuts arise in the FFs for $B\to D^{(*)}$,...
The fact that the quark and charged-lepton mass spectrum is hierarchical remains a tantalising hint that beyond-SM physics might be at play. I will review work I completed with Baker and Cox on a systematic analysis of 1-loop generation of the bottom and tau masses, which are, of course, known to be suppressed compared to the fundamental electroweak scale. Note that both of those species have...
We revisit a class of lepton-flavor non-universal $\mathrm{U}(1)$ gauge extensions of the Standard Model, first introduced in~\cite{Davighi:2022qgb}, which provides a subtle mechanism to simultaneously accommodate the observed neutrino masses and mixing angles via a high-scale seesaw while predicting exact proton stability to all orders in the effective field theory, ensured by a residual...
In this talk, I will discuss the generation of a lepton asymmetry during
a first-order cosmological phase transition at which the sterile neutrinos of the seesaw
mechanism acquire their masses. Contrary to previous works who studied the same
problem, we compute the lepton asymmetry by solving quantum kinetic equations
derived from nonequilibrium quantum field theory, which take into...
I will discuss recent progress in the determination of parameters of thermal-phase transitions, relevant for describing production of gravitational wave backgrounds in the early Universe, using effective field theory (EFT) methods. I will highlight the importance of including previously neglected terms in the EFT expansion and the difficulties and solutions for computing the corresponding...
Vacuum decay through runaway first order phase transitions presents a unique opportunity for particle physics and cosmology: collisions of vacuum bubbles can act as cosmic scale high energy colliders close to the Planck scale, providing access to high energy physics far beyond any temperature or energy scale ever reached in the history of our Universe. This talk will cover recent developments...
Ultralight dark matter can induce oscillations in fundamental constants of nature, such as the fine-structure constant, the strength of the strong interaction, and particle masses. These oscillations can be probed through highly precise measurements of transition frequencies in atomic, molecular, and nuclear systems. This talk will focus on the potential for detecting ultralight dark matter...
Baryon and lepton number are excellent low-energy symmetries of the Standard Model (SM) that tightly constrain the form of its extensions. In this work, we investigate the possibility that these accidental symmetries are violated in the deep UV, in such a way that one multiple necessary for their violation lives at an intermediate energy M above the electroweak scale. We write down the...
A longstanding mismatch of the theoretical predictions and experimental measurements of $D$-meson mixing parameters stands at a couple orders of magnitude. The Glashow–Iliopoulos–Maiani (GIM) mechanism is responsible for the cancellations which leave $SU(3)$ breaking effects highly suppressed - to the fourth power. Higher order corrections, as well as nonperturbative effects, may give rise to...
In this poster, we present an in-depth investigation of the recently found issues in the FxFx matching-merging procedure in MadGraph5_aMC@NLO for usage at the LHC. We compare the predictions for $W+3$ jets and $Z+3$ jets against corresponding measurements from ATLAS and CMS, studying a variety of final-state kinematic distributions and highlighting regions where mismatches are most pronounced....
The study of cosmological first order phase transitions, and the associated gravitational wave signal, has seen growing interest in recent years, driven by the prospects of detection with next-generation ground- and space-based interferometers.
Here, I present PT2GWFinder, a Mathematica package designed to compute phase transition parameters and the gravitational wave power spectrum for an...
We revisit the computation of the electroweak vacuum decay rate in the Standard Model, incorporating the full one-loop prefactor and focusing on the gauge degrees of freedom. Using group theoretical arguments, we derive the correct degeneracy factors in the functional determinant and identify an overcounting of transverse modes in previous calculations. The new result modifies the gauge...
The axion was originally introduced in the 70s to explain the absence of CP-violating effects in quantum chromodynamics (QCD) through the Peccei-Quinn (PQ) mechanism. It is a pseudo-scalar boson whose mass and couplings to standard model particles are related to the energy scale where the so called Peccei and Quinn symmetry is broken. Several axion models have been proposed, with the common...
We present an axion model based on the Pati-Salam group, where $\mathrm{SU}(3)_{f_R}$ (part of flavor symmetry) has also been gauged. The choice of field content ensures a careful interplay of the two symmetries, such that an accidental global $\mathrm{U}(1)$ Peccei-Quinn (PQ) symmetry emerges. The resulting axion is of high quality for the breaking scale in a certain range, and the model's...
The QCD axion does not need to be a perfect pseudoscalar for solving the strong CP problem. I will discuss a cosmological role of such imperfectness by solving the domain wall problem that prevails in post-inflationary axion models with discrete symmetry. Effective operators, where the Peccei-Quinn field linearly couples to Standard Model particles, can provide a dynamical solution to the...
Axion-like particles (ALPs) are a common feature in many extensions of the Standard Model. However, their stability is not guaranteed by any symmetry, making the consideration of their lifetime crucial when investigating their cosmological consequences. In this talk, I will explore two distinct ALP mass regimes and their corresponding signatures. First, I will focus on sub-eV ALPs, presenting...
A new set of experiments will deliver in the next few years unprecedented sensitivity to Lepton Flavor Violating (LFV) muon decays. Mu3e, proposed at PSI (Switzerland), will focus on observing $\mu\to 3e$ decays, with a projected target of $10^{15}$ muons decaying at rest, and excellent electron/positron track reconstruction. In this talk I will review the current and future statues of these...
The cosmological history of axions is most predictive when their associated symmetry is restored in the post-inflationary universe, producing a network of cosmic strings. On the other hand, arguably the most well-motivated (high-quality) axions — those arising from extra dimensions and string theory — are often thought to be in tension with this scenario. In this talk, I explain how these are...
Abstract: I discuss paradoxical situation in detection of the highest energy cosmic rays by Telescope Array and Pierre Auger experiments, in particular, a strong discrepancy between their results for cosmic ray fluxes at energies above the GZK cutoff, most notably at E>100 EeV. I also discuss ideas of new BSM physics and dark matter identity which could naturally resolve these paradoxes.
I will present a novel mechanism for producing primordial black holes (and beyond) in the post-inflation universe. The mechanism invokes an epoch of early matter domination, and self-interactions of the dominating particles, which trigger a gravothermal collapse of halos into black holes. The gravothermal collapse also gives rise to other exotic compact objects including boson stars, as well...
I will briefly review the physics of the Q-balls. Particular attention will be paid on the Q balls interactions with its perturbations and its phenomenological aspects for the early universe.
We discuss a variety of topological structures that are predicted in realistic extensions of the Standard Model.
We also show how primordial monopoles, cosmic strings and other extended structures can cope with cosmic inflation.
Plasma wakefield acceleration offers a new path toward building compact, high-energy colliders, with the potential to open up fresh opportunities for new physics searches. In this talk, I’ll introduce the basic ideas behind the technology and discuss what a future plasma wakefield collider could look like. I’ll then explore its reach for discovering new particles using simple benchmark models,...
I will discuss the physics potential of coherent elastic neutrino-nucleus scattering (CEvNS), a neutral-current process in which a neutrino scatters off an entire nucleus. I will first briefly review the main features of CEvNS and the status of current observations. Then, I will discuss how these measurements have opened the window to many physics applications, from Standard Model precision...
Long-lived particles (LLPs) arise in many theories beyond the Standard Model. These may be copiously produced from meson decays (or through their mixing with the LLP) at neutrino facilities and leave a visible decay signal in nearby neutrino detectors. We compute the expected sensitivity of the DUNE liquid argon (LAr) and gaseous argon (GAr) near detectors (ND) to light LLP decays. In doing...
Neutrino trident production is a rare Standard Model process, sensitive to the structure of the electroweak interaction. Flavour-violating tridents are also an important background to searches for deviations from lepton flavour symmetry beyond the Standard Model. Entering a frontier of precision neutrino physics comes with new regimes of energy-spread and intensity of accelerator neutrino...
