Effective field theories are a very powerful mean to describe theories at energies well below a certain cutoff scale. However, not all points in the parameter space spanned by their coefficients allow for a UV completion that is both unitary and analytic, and various bounds have been derived in the literature. These bounds attain particular phenomenological relevance when applied to the...
Some New Physics scenarios that can explain the hints of Lepton Flavor Universality Violation (LFUV) observed in the B-meson decays also predict Lepton Flavor Violating (LFV) decay modes. We explore minimalistic scenarios involving leptoquark states at the $\mathcal{O}(\mathrm{TeV})$ scale which are consistent with low energy flavor physics observables. We show that the upper bound on LFV...
$SU(2)_L$-invariance links charged dilepton $\bar{q}\,q^\prime\,\bar{\ell}\,\ell$ and dineutrino $\bar{q}\,q^\prime\,\bar{\nu}\,\nu$ couplings.
This connection can be established using SMEFT and holds model-independently if only SM-like left-handed light neutrinos are present. This allows to perform complementary experimental tests of lepton universality and charged lepton flavour...
Higgs production in association with a photon at hadron colliders is a rare process, not yet observed at the LHC. We show that this process is sensitive to significant deviations of Higgs couplings to first and second generation SM quarks (particularly the up-type) from their SM values, and use a multivariate neural network analysis to derive the prospects of the High Luminosity LHC to probe...
We study an extended 2 Higgs doublet model (2HDM) in which the Standard Model (SM) Yukawa interactions are forbidden due to a global $U(1)^\prime$ symmetry, but may arise via mixing with vector-like families. In this model, the hierarchical structure of Yukawa couplings of quarks and leptons in the SM arises from the heavy masses of the fourth and fifth vector-like families. Within this model,...
In recent years particle physics research has undergone somewhat of a phase transition, looking increasingly towards hidden sectors and the feebly interacting frontier. In this talk I will introduce a new approach to parameterising dark sector forces, underpinned by the Källén-Lehman representation, in which the effects of any general scalar fifth force are captured by a single...
We apply on-shell amplitude techniques to the study of neutrino oscillations in vacuum, focussing on processes involving W bosons. We start by determining the 3-point amplitude involving one neutrino, one charged lepton and one W boson, highlighting all the allowed kinematic structures. The result we obtain contains terms generated at all orders in an expansion in the cutoff scale of the...
Neutrino oscillations occur due to non-zero masses and mixings and most importantly
they are believed to maintain quantum coherence even over astrophysical length scales. In the present study, we explore the quantumness of three flavour neutrino oscillations by studying the extent of violation of Leggett-Garg inequalities (LGI) if non-standard interactions are taken into account. We report an...
Current limits for the tau-neutrino transition magnetic moment to a sterile neutrino are far weaker than its electron and muon counterparts. In this poster/talk I discuss on-going work to investigate possible constraints on the transition magnetic moment between the tau neutrino and an O(MeV) sterile neutrino at DUNE: the proposed neutrino-beam experiment at FermiLab. I compare this with...
The simplest extension of the SM to account for the observed neutrino masses and mixings is the addition of at least two singlet fermions (or right-handed neutrinos). If their masses lie at or below the GeV scale, such new fermions would be produced in meson decays. Similarly, provided they are sufficiently heavy, their decay channels may involve mesons in the final state. Although the...
Type-II seesaw mechanism has been widely studied already as the link between neutrino mass generation beyond Standard Model (SM) and leptogenesis. In this study, the SM is minimally extended by two triplet Higgs scalars (with hypercharge $Y=2$), with one triplet having complex vacuum expectation value (vev) to impose generality. The triplet vevs are bounded by the $\rho$-parameter constraint...
The detection of Coherent Elastic Neutrino-Nucleus Scattering (CEʋNS) represents an experimental challenge because of its unique signature: a nuclear recoil with low energy in range of 10 to 100 eV on average.
This process, largely unexplored until today, could probe physics beyond the Standard Model such as non-standard neutrino interactions and electromagnetic form factors.
NUCLEUS is a...
The CUORE experiment is a ton-scale array of TeO$_2$ cryogenic bolometers located at the underground Gran Sasso National Laboratories, in Italy. The CUORE detector consists of 988 crystals operated as source and detector at a base temperature of $\sim$10 mK. The primary goal of CUORE is the search for neutrinoless double beta (0$\nu\beta\beta$) decay of $^{130}$Te, but thanks to its large...
The Cryogenic Underground Observatory for Rare Events (CUORE) experiment is an ongoing search for neutrinoless double beta decay located at the Gran Sasso National Laboratory (LNGS) in Italy. Recent work has found that the CUORE calorimeters are sensitive to acoustic and seismic events originating from outside the detector at LNGS. To measure the effect of these mechanical disturbances on the...
The exotic contributions of sfermions, neutralinos, and gluinos to neutrinoless double beta decay (0νββ) in the presence of R-parity violating (RPV) couplings have been known for some time. In this talk and poster, we update the sensitivity of 0νββ to the lightest mostly-bino neutralino over the neutralino mass range 0.1 MeV - 10 TeV, constraining the RPV coupling in a way that is compatible...
At present, cosmological observations set the most stringent bound on the neutrino mass scale. Within the standard cosmological model ($\Lambda$CDM), the Planck collaboration reports $\sum m_\nu < 0.12\,\text{eV}$ at 95 % CL. This bound, taken at face value, excludes many neutrino mass models. However, unstable neutrinos, with lifetimes shorter than the age of the universe $\tau_\nu \leq t_U$,...
We consider a dark sector with multiple dark fermions interacting under a dark U(1) gauge interaction, mediated by a massless dark photon, with no kinetic mixing. Apart from this self interaction, a portal interaction, mediated by scalar messengers, exists between dark fermions and SM fermions. The species which contribute to the total matter relic density of the Universe, are the stable dark...
Belle II is a B-Factory experiment designed to produce precision measurements of CP violation in the weak sector as well as search for Beyond the Standard Model particle physics. The $e^{+}e^{-}$ collisions are created by the SuperKEKB accelerator which has achieved a world record of instantaneous luminosity of $2.4 \times 10^{34} {\text{cm}^{-2}}{\text{s}^{-1}}$. One of the highest priorities...
In light of the recent measurement of the anomalous muon magnetic moment which confirms a tension with the standard model, we revisit the light vector boson explanation of this discrepancy and show that there is still available parameter space in the context of models with co-annihilating dark matter or dark heavy neutral fermions. Reinterpreting the bounds from B factories with a semi-visible...
Massive photon-like particles are predicted in many extensions of the Standard Model as possible portals to a hidden sector where Dark Matter is secluded [1]. They are vector bosons mediating the interaction between ordinary and dark matter and can be produced in different processes through a feeble mixing to the photon. The PADME experiment [2], conducted at Laboratori Nazionali di Frascati...
In this talk I will discuss the possibility of obtaining a viable Dark Matter candidate in the context of a gauged, anomaly-free, flavor dependent U(1)' symmetry. I will discuss the relic density constraints, as well as the direct detection and neutrino physics input to the model. Possible detection at future experiments, such as SuperCDMS SNOLAB, is also considered.
In this talk I will give an overview of my research work on Accidental Dark Matter models. I briefly discuss some general aspects of Dark Matter model building and I show examples of specific models I have studied.
In this talk I discuss the viability of higgs portal majorana dark matter in light of current constraints, considering parameter ranges motivated by the thermal relic abundance and the potential GCE annihilation signal. Typically in these types of models, the mass of the dark matter is tuned so that annihilation occurs through the higgs resonance, in order to get a large enough annihilation...
The existence of a SM-neutral and light dark sector coupled to the visible sector via irrelevant portal interactions was considered in [$2012.08537$][1]. Such scenarios tend to be common in dark matter models arising as various extensions of the Standard Model.
The authors of $2012.08537$ use the conformal behaviour of this dark sector at energies $\Lambda_{IR} << E << \Lambda_{UV}$ to study...
In our work we study the cosmological phase transition (PT) in a conformal extension of the Standard Model (SM). The model considered is called SU(2)cSM, it extends the SM gauge group by an additional hidden SU(2)$_X$ gauge group, and a scalar doublet (whilist singlet under SM gauge group). The tree-level potential has no mass terms, all the masses are generated via the Coleman-Weinberg...
Unusual masses of black holes being discovered by gravitational wave experiments pose fundamental questions about the origin of these black holes. More interestingly, black holes with masses smaller than the Chandrasekhar limit ($\sim$ 1.4 $M_{\odot}$) are essentially impossible to produce through any standard stellar evolution. Primordial black holes, with fine-tuned parameters and with no...
I present the one-loop contributions to ALP-SM couplings stemming from effective ALP operators, including all finite corrections. The complete leading-order (dimension five) effective linear Lagrangian is considered. These corrections can become a useful tool to test ALP-SM interactions which are hard to measure via their loop impact on other observables that are more experimentally...
The theoretical calculation for pseudo--scalars hadronic decays $P \to M a$, with the Axion-Like-Particle escaping
the detection, is reviewed. While one-loop penguin contributions are usually considered, tree-level processes have
most often been overlooked in literature. Following the Brodsky/Lepage approach the tree-level contribution to the
ALP pseudo--scalar decay is estimated....
Pseudo-Nambu-Goldstone bosons (pNGBs) are attractive dark matter (DM) candidates since they are coupled to the Standard Model (SM) predominantly through derivative interactions. Thereby, they naturally evade the strong existing limits inferred from DM direct detection experiments. Working in an effective field theory that includes both derivative and non-derivative DM-SM operators, we perform...
In my talk and poster, I will motivate dark matter from composite Higgs models. In this framework, the dark matter candidate is a pseudo-Nambu Goldstone boson (pNGB) of a spontaneously broken symmetry, that lies naturally at the electroweak scale. In non-minimal scenarios, other pNGBs arise which can be lighter than the dark matter candidate and therefore affect its phenomenology significantly...
A fast-spinning axion can dominate the Universe at early times and generates the so-called kination era. The presence of kination imprints a smoking-gun spectral enhancement in the primordial gravitational-wave (GW) background. Current and future-planned GW observatories could constrain particle theories that generate the kination phase. Surprisingly, the viable parameter space allows for a...
The $\sigma_8$-tension of Planck data with weak lensing and redshift surveys is one of the main problems with the $\Lambda$CDM model of cosmology. We show that the tension can be alleviated by introducing an interaction between dark matter and neutrinos. We model the interaction using a linear Boltzmann treatment, introducing a novel implementation that for the first time uses the full massive...
I will present recent application of the SN 1987A cooling bound to set a constraint on dark flavored sectors. This is possible thanks to the fact that the protoneutron stars are hot and dense environments where hyperons can be efficiently produced. Therefore a decay of the form Λ→nX0, where X^0 is a new bosonic dark particle, will be severely constrained. I will explain the ingredients...
The reason why dwarf spheroidal and other galaxies appear to have a lower central density than predicted from N-body simulations based on LCDM cosmology is still an open question.
Apart from the possibility that baryonic physics could play a leading role in shaping the inner density profile of galaxies, the most popular new-physics explanation is to assume heat transfer caused by dark matter...
Could Dark Matter (DM) be made of Primordial Massive Black Holes (PMBHs) with such mass as detected by LIGO? The amplitude and frequency of gravitational microlensing can be used to detect PBHs. However, they can be mixed with the normal stellar population that can also contribute to microlensing. To separate the contributions from both populations, we perform numerical simulations to study...
Following theoretical (high-energy physics) considerations, we explore the possibility that our Universe contains a negative cosmological constant, dubbed $\lambda$, on top of an additional component $X$ accounting for the late-time accelerated stage of expansion. In this talk, I will present some of the cosmological implications of introducing $\lambda$. In particular, we will assess the...
The proximity of our Galaxy's center presents a unique opportunity to study a galactic nucleus with orders of magnitude higher spatial resolution than can be brought to bear on any other galaxy. After more than a decade of diffraction-limited imaging on large ground-based telescopes, the case for a supermassive black hole at the Galactic center has gone from a possibility to a certainty,...
We propose a new approach to explore the neutral-current non-standard neutrino interactions (NSI) in atmospheric neutrino experiments using oscillation dips and valleys in reconstructed muon observables, at a detector like ICAL. We show that the non-zero value of NSI parameter $\varepsilon_{\mu\tau}$ shifts the oscillation dip locations in $L/E$ distributions of the up/down event ratios of...
We point out that the states required by the Lattice Weak Gravity Conjecture, along with certain genericity conditions, imply the existence of non-vanishing kinetic mixing between massless Abelian gauge groups in the low-energy effective theory. We carry out a phenomenological estimate using a string-inspired probability distribution for the masses of superextremal states and compare the...
Axion fragmentation may serve as a mechanism to produce the observed DM abundance, which makes it possible for axion DM to appear with lower values of the decay constant than those allowed by the conventional misalignment mechanism. Specifically, regions of parameter space accessible to a range of experiments may contain such viable DM candidates. Fragmentation can take place if a light scalar...
The observation of neutrinoless double beta decay ($2\beta0\nu$) would be a breakthrough in our understanding of particle physics. It could give an answer on the nature of neutrinos (Dirac or Majorana Particles), prove the violation of the lepton number, and explain the asymmetry matter/antimatter. This is why, since many years, physicists are thinking and building huge experiments with the...
The Minimal Linear $\sigma$ Model is a useful theoretical laboratory. One can investigate in a perturbative renormalisable model the properties of the Higgs boson as a pseudo-Goldstone boson, the phenomenological effects of the radial mode of the field $s$ which spontaneously breaks the global $SO(5)$ symmetry and the validity of conclusions based on the Effective Field Thery (EFT) approach ...
We introduce a new approach for training jet taggers based on multivariate methods, where the mass and transverse momentum are input variables, along with jet substructure observables, varying over wide ranges. Known as Mass Unspecific Supervised Tagging (MUST), this strategy allows the development of taggers that are sensitive to different types of signal and efficient across large...
The ENUBET experiment, included in the CERN Neutrino Platform effort as NP06/ENUBET, is developing a new neutrino beam based on conventional techniques in which the flux and the flavor composition are known with unprecedented precision ($\mathcal{O}$(1%)). Such a goal is accomplished monitoring the associated charged leptons produced in the decay region of the ENUBET facility. Positrons and...
The India-based tin detector (TIN.TIN) proposes to explore neutrinoless double beta decay in the isotope $^{124}Sn$ by employing an array of cryogenic tin-based bolometers which will be operated at ~10 mK. However, pure tin is susceptible to tin pest, an allotropic phase transition of tin near ambient conditions which results in the mechanical failure of the tin sample. This poses a concern...
A detailed understanding of Earth’s Matter effect is inevitable to correctly analyze the data from the upcoming high-precision long-baseline experiments to resolve the remaining fundamental unknowns such as neutrino mass ordering, leptonic CP violation and precision measurements of the oscillation parameters. In this paper, for the first time, we explore in detail the capability of Deep...
While overwhelming cosmological evidences point to the existence of Dark Matter (DM), only its gravitational interaction has been experimentally confirmed. Limitations on the most general mono-X DM signature at colliders motivate searches beyond this. This could manifest in the form of a weak multiplet/doublet DM via weak interactions giving multilepton plus missing energy final states that...
Axion-like particles (ALPs) play an important role for inflationary model building, as well as are well motivated dark matter candidates. The out-of-equilibrium initial conditions, combined with their possibly nontrivial potentials, allow for a rich nonlinear dynamics of such fields in the early universe.
We consider coherent oscillations of an ALP field in a wiggly potential and...
In the next decade, ultra-high-energy neutrinos in the EeV-ZeV energy range will be potentially detected by next-generation neutrino telescopes. Although their primary goals are to observe cosmogenic neutrinos and to gain insight into extreme astrophysical environments, they have the great potential of indirectly probing the nature of dark matter. In this talk, we study the projected...
Recent weak lensing surveys have revealed that the direct measurement of the parameter combination S8 = σ8 (Ωm/0.3)^0.5-- measuring the amplitude of matter fluctuations on 8 Mpc/h scales -- is ∼3σ discrepant with the value reconstructed from cosmic microwave background (CMB) data assuming the ΛCDM model. In this talk, I discuss that it is possible to resolve the tension if dark matter (DM)...
In dark-energy models where a scalar field is nonminimally coupled to the spacetime geometry, gravitational waves are expected to be supplemented with a scalar mode. Such scalar waves may interact with the standard tensor waves, thereby affecting their observed amplitude and polarization. Understanding the role of scalar waves is thus essential in order to design reliable gravitational-wave...
One of the main questions of fundamental physics is the problem of the asymmetry matter/antimatter in the universe and the action of gravity on antimatter. Tests on antimatter gravity have currently a limited precision, with the sign of gravity acceleration not yet known experimentally. Ambitious projects are developed at CERN facilities to produce low energy antihydrogen with the aim of...
Explaining the tiny neutrino masses and non-zero mixings have been one of the key motivations for going beyond the framework of the Standard Model (SM). We discuss a collider testable model for generating neutrino masses and mixings via radiative seesaw mechanism. That the model does not require any additional symmetry to forbid tree-level seesaws makes its collider phenomenology interesting....
The recent tension between local and early measurements of the Hubble constant can be explained in a particle physics context. A mechanism is presented where this tension is alleviated due to the presence of a Majoron, arising from the spontaneous breaking of Lepton Number. The lightness of the active neutrinos is consistently explained. Moreover, this mechanism is shown to be embeddable in...
I will present our recent work on a simple scoto-seesaw model that accounts for dark matter and neutrino masses with spontaneous CP violation. This is achieved with a single horizontal Z8 discrete symmetry, broken to a residual Z2 subgroup responsible for stabilizing dark matter. CP is broken spontaneously via the complex vacuum expectation value of a scalar singlet, inducing leptonic...
We present a new module of MadDM that enables the complete automation of the computation of loop-induced processes, relevant for indirect detection of dark matter. The interface between MadDM and MadLoop allows for the calculation of any annihilation cross-section of dark matter into $\gamma X$, where $X=\gamma, Z, H$ or a new unstable particle contained in the dark matter model, odd under the...
We study the capabilities of the DUNE near detector to probe deviations from unitarity of the leptonic mixing matrix, the 3+1 sterile formalism and NSI in detection and production, clarifying the relation and possible mappings among the three formalisms. We add to the current analyses in the literature the use of the charged current events for the ντ appearance channel and the consideration of...
We point out novel kaon and pion decays to several leptons pairs that can probe states beyond the Standard Model at the MeV scale. In particular, modes like K → π 2(e+e-) have never been measured or considered before and could be used to search for MeV axions, as well as multi-component dark sectors. In particular, the ``17 MeV QCD axion" is robustly tested with these signatures, as it...
We investigate if the CP violation necessary for successful electroweak baryogenesis may be sourced by the neutrino Yukawa couplings. In particular, we consider an electroweak scale Seesaw realization with sizable Yukawas where the new neutrino singlets form (pseudo)-Dirac pairs, as in the linear or inverse Seesaw variants. We find that the baryon asymmetry obtained strongly depends on how the...
Non-resonant searches take advantage on the derivative nature of the interaction between Axion-Like particles and the particles in the Standard Model. In this talk I would like to review the work carried out by our group (ALPs $\&$ Colliders IFT-UAM) on the matter of VBS as a key channel to probe electroweak ALP couplings (independently of gluon-ALP coupling).
We explore the discovery prospect of a relatively light right handed neutrino (RHN) state at the proposed $ep$ collider LHeC, which is planned to operate with 60 GeV electron beam and 7 TeV proton beam. We consider $\tilde{R}_2$ class of leptoquark model, which offers a large production cross-section of RHN along with a jet. For the chosen mass range, the RHN is boosted and can undergoes...
We study the status of the reactor antineutrino anomaly in light of new reactor flux models from both conversion and summation methods. We find that both the reactor rate and fuel evolution data are consistent with the predictions both from the conversion model of Kopeikin et al. and the summation model of Estienne et al. The convergence of both model predictions indicatesthe rebustness for...
We explore relativistic freeze-in production of scalar dark matter in gauged $B-L$ model, where we focus on the production of dark matter from the decay and annihilation of Standard Model (SM) and $B-L$ Higgs bosons. We consider the Bose-Einstein (BE) and Fermi-Dirac (FD) statistics, along with the thermal mass correction of the SM Higgs boson in our analysis. We show that in addition to the...
We examine the impact of a faster expanding Universe on the phenomenology of scalar dark matter (DM) associated with SU(2) multiplets. Earlier works with radiation dominated Universe have reported the presence of desert region for both inert SU(2) doublet and triplet DM candidates where the DM is under abundant. We find that the existence of a faster expanding component before BBN can revive a...
The Standard Model (SM) of particle physics is currently the best known description of the fundamental constituents of matter and their interactions. However, among other things, it cannot explain the existence of dark matter, and some experimental results deviate from SM predicitons, suggesting the possibility of including New Physics by extending the SM. Possible extensions are known as dark...
In this presentation, I will talk about the prospects to search for a muonic dark force at Belle II in events with four muons in the final state. These events could be due to a new gauge boson Z$^{\prime}$ which couples only to the second and third lepton family. A short description of the background suppression technique, based on artificial neural networks, and the fitting strategies for the...
Ultralight bosonic dark matter can induce temporal variation in the masses and coupling of the Standard Model. A coupling between this dark matter candidate and neutrinos could lead to three different signatures in oscillation experiments: a time modulation of the signal, a distortion in the oscillation probability or it could manifest as a fast-varying matter potential.
In a bid to simultaneous explanation of dark matter (DM) and tiny but non-zero masses of left-handed neutrinos, we propose a minimal extension of the Standard Model (SM) by a vector-like fermion doublet and three right handed (RH) singlet neutrinos. The DM arises as a mixture of the neutral component of the fermion doublet and one of the RH neutrinos, both assumed to be odd under an additional...
We study the phenomenology of the minimal inverse-seesaw model composed of two ‘right-handed neutrinos’ and two sterile singlet fermions, besides the Standard Model (SM) particle content. The model is supplemented with Abelian flavour symmetries to ensure maximal predictability and establish the most restrictive flavour patterns which can be realised by those symmetries. This setup requires...
Low-energy neutrinos are clean messengers from supernovae explosions and probably carry unique insights into the process of stellar evolution. We estimate the expected number of events considering coherent elastic scattering of neutrinos off silicon nuclei, as would happen in Charge Coupled Devices (CCD) detectors. The number of expected events, integrated over a window of about 18 s, is ∼ 4...
We study axion effective field theories (EFTs), with a focus on axion couplings to massive chiral gauge fields. We investigate the EFT interactions that participate in processes with an axion and two gauge bosons, and we show that, when massive chiral gauge fields are present, such interactions do not entirely originate from the usual anomalous EFT terms. When applied to the case of the...
In the context of holography, a black hole horizon is commonly introduced to model finite temperatures. However, this choice is not unique. We investigate the minimal features that a more general metric should display in order to describe a system at a finite temperature, using semi-analytical techniques and well-established holographic superconductor models as our testing ground. The...
The recent measurement of the muon g−2 anomaly continues to defy a Standard Model explanation. Although such anomaly can be accommodated within the framework of two Higgs doublet models, one of the most popular scalar sector extensions, the allowed parameter space has been further restricted due to conflicts with several constraints. However, if one includes extra fermion content in the form...
General Relativity predicts that the passage of matter or radiation from an asymmetrically-emitting source should cause a permanent change in the local space-time metric. This phenomenon, called the \emph{gravitational memory effect}, has never been observed, however supernova neutrinos have long been considered a promising avenue for its detection in the future. With the advent of deci-Hertz...
We consider the generation of neutrino masses via a singly-charged scalar singlet. Under general assumptions we identify two distinct structures for the neutrino mass matrix. This yields a constraint for the antisymmetric Yukawa coupling of the singly-charged scalar singlet to two left-handed lepton doublets, irrespective of how the breaking of lepton-number conservation is achieved. The...
The Astroparticle Physics Group at the University of Zurich operates a high-purity germanium (HPGe) spectrometer (Gator) in a low-background environment underground at the Laboratori Nazionali del Gran Sasso (LNGS) in Italy. The 2.2 kg $\gamma$-ray spectrometer is one of the world’s most sensitive HPGe detectors with an integrated count rate of (85.0 ± 0.9) events/(day kg) in the energy...
