PLANCK2024

3 Jun 2024, 08:30 → 7 Jun 2024, 21:00 Europe/Lisbon

Anfiteatro Abreu Faro (IST, Lisboa)

PLANCK2024 - The 26th International Conference From the Planck Scale to the Electroweak ScalePLANCK2024 is the 26th  in the series of Conferences "From the Planck scale to the electroweak scale". The Planck Conferences cover a broad spectrum of physics beyond the Standard Model and of the interface between Particle Physics and Cosmology with emphasis on the theoretical aspects related to the present experimental programmes.

The Conference is intended to bring together researchers working in a wide variety of topics, including Flavour Physics, Neutrino Physics, Higgs physics, CP violation, Collider Physics and Cosmology (e.g. Dark Matter and Gravitational Waves) to present new results, stimulate discussions and new collaborations.

PLANCK2024 will be held at Anfiteatro Abreu Faro, Instituto Superior Técnico (IST) Av. Rovisco Pais, 1049-001 Lisboa, Portugal, from the 3rd to the 7th of June 2024. 

Local Organising Committee:	Scientific Secretariat:	Secretariat:
Gustavo C. Branco (Chair) M. (Gui) N. Rebelo (Vice-Chair) Ricardo G. Felipe Filipe Joaquim  Gregory Patellis J. (Juca) I. Silva-Marcos	Francisco Albergaria José Bastos   Aditya Batra Henrique Câmara Anton Kunčinas Miguel Levy José Rocha	Dulce Conceição    Sandra Oliveira

International Advisory Committee:
Ignatios Antoniadis (LPTHE, Sorbonne University, Paris) R. Barbieri (Scuola Normale Superieure, Pisa) J. Ellis (King's College, London and CERN) H. P. Nilles (University of Bonn) S. Pokorski (University of Warsaw) M. Quirós (Institute of High Energy Physics, Barcelona) G. Senjanović (GSSI, L'Aquila and ICTP, Trieste)

Supported by:

PLANCK2024 Info.pdf

planck2024-poster.pdf

Monday 3 June

08:30 → 09:15 Registration

09:15 → 09:30 Conference Opening 09:15 - 09:30

09:30 → 10:00 S-Matrix and naturalness

TBA

Speaker: Georgi Dvali

Dvali.pdf

10:00 → 10:30 Flavor Physics: from the past to the future we have to go through the present

TBA

Speaker: Guido Martinelli (Sapienza Universita e INFN, Roma I (IT))

Martinelli_Planck2024.pdf

10:30 → 11:00 Coffee Break

11:00 → 11:30 Probing SUSY at Gravitational Wave Observatories

Speaker: Stefan Antusch

Antusch_SUSY-GWs_2024.pdf

11:30 → 12:00 Charge-breaking opportunities in the early Universe

TBA

Speaker: Igor Ivanov (Sun Yat-sen University, Zhuhai, China)

Planck-2024-Igor-Ivanov.pdf

12:00 → 12:30 Majorana mass generation in the early universe

TBA

Speaker: Pasquale Di Bari (University of Southampton)

DIBARI4PLANCK2024.pdf

DIBARI4PLANCK2024.pdf

12:30 → 14:30 Lunch Break

There are many restaurants around IST. There are also several cafeterias inside IST

14:30 → 15:00 Nilpotent Fierz-Pauli

TBA

Speaker: enrique alvarez

Avarez.pdf

15:00 → 15:30 Physics Results from ATLAS

TBA

Speaker: Patricia Conde Muino (Laboratory of Instrumentation and Experimental Particle Physics (PT))

ATLASPhysics_conde_Planck2024.pdf

15:30 → 16:00 ALP coupling to fermions: CP-even and CP-odd

TBA

Speaker: Belen Gavela Legazpi (UAM)

Gavela-Planck-2024-Lisbon-June-2024 .pdf

16:00 → 16:30 Coffee Break

16:30 → 17:00 The basis invariant flavor puzzle

TBA

Speaker: Andreas Trautner

Trautner_Basis_Invariant_Flavor_Puzzle_PLANCK_Lisbon_24.pdf

17:00 → 17:30 Searching for Primordial gravitational waves in angular correlations of the Cosmic Microwave Background

Speaker: Miguel Sanchis Lozano (Univ. of Valencia and CSIC (ES))

Lozano.pdf

19:00 → 22:00 Reception

Tuesday 4 June

09:30 → 10:00 Lepton family numbers of neutrinos at low energies and leptogenesis

TBA

Speaker: Takuya Morozumi

MOROZUMI.pdf

10:00 → 10:30 The quantumness of particle decays

TBA

Speaker: Juan Antonio Aguilar Saavedra (Consejo Superior de Investigaciones Científicas (ES))

quantum.pdf

10:30 → 11:00 Coffee Break

11:00 → 11:30 Top quark Production with Invisible Particles @ the LHC

TBA

Speaker: Antonio Onofre (Universidade do Minho/CFUMUP,LIP)

ttX-Invisible.pdf

11:30 → 12:00 Fermion mass hierarchy and CP violation in modular symmetry

TBA

Speaker: MORIMITSU TANIMOTO

TANIMOTO.pdf

12:00 → 12:30 Gravitational Waves as Probes of New Physics

TBA

Speaker: Stephen Frederick King

King_Planck_2024.pdf

12:30 → 14:30 Lunch Break

14:30 → 16:10 Parallel Session PI.1

Convener: Miguel Nebot

14:30 The automation of SMEFT-assisted constraints on UV-complete models

The ongoing Effective Field Theory (EFT) program at the LHC and elsewhere is motivated by streamlining the connection between experimental data and UV-complete scenarios of heavy new physics beyond the Standard Model (BSM). This connection is provided by matching relations mapping the Wilson coefficients of the EFT to the couplings and masses of UV-complete models. Building upon recent work on the automation of tree-level and one-loop matching in the SMEFT, we present a novel strategy automating the constraint-setting procedure on the parameter space of general heavy UV-models matched to dimension-six SMEFT operators. A new Mathematica package, match2fit, interfaces MatchMakerEFT, which derives the matching relations for a given UV model, and SMEFiT, which provides bounds on the Wilson coefficients by comparing with data. By means of this pipeline and using both tree-level and one-loop matching, we derive bounds on a wide range of single- and multi-particle extensions of the SM from a global dataset composed by LHC and LEP measurements. Whenever possible, we benchmark our results with existing studies. Our framework realises one of the main objectives of the EFT program in particle physics: deploying the SMEFT to bypass the need of directly comparing the predictions of heavy UV models with experimental data.
Additionally, thanks to upcoming work, this framework allows to easily obtain projected bounds on the same models from HL-LHC, FCC-ee or CEPC projections.
Based on arXiv:2309.04523 and upcoming work.

Speaker: Alejo Nahuel Rossia (University of Manchester)

Rossia_Planck_PDF2024.pdf

14:50 On Shell Matching

Effective field theories (EFTs) have become an essential tool in the search of new physics beyond the Standard Model. The calculation of the Wilson coefficients of the EFT for specific new physics models is usually performed by matching off-shell one-light-particle irreducible Green functions, which requires an off-shell basis of effective operators. This so-called Green's basis includes some operators that are redundant and can be written in terms of a minimal, physical basis when computing on-shell observables. This reduction is traditionally achieved by applying field redefinitions and equations of motion (EOMs). However, the absence of a systematic way of identifying the optimal field redefinition, coupled with the limitation that EOMs are only valid up to linear order in the perturbative expansion, calls for the search of a more systematic approach to the reduction of the Green's basis.

Our proposed method consists on performing a tree-level on-shell matching between the Green's and the physical bases. This matching requires a delicate cancellation between non-local contributions in both theories that we sidestep by evaluating the amplitudes with randomly generated physical momenta. Here, we present the application of this procedure to the dimension-eight Green's basis reduction of a toy model consisting on a real scalar field with Z2 symmetry. Furthermore, we derive the reduction of a set of bosonic operators in the SMEFT.

Speaker: FUENSANTA VILCHES BRAVO Not Supplied

OnShell-Matching_FuesantaVilches.pdf

15:10 Functional Matching at two-loop order

Effective field theories have been gathering increasing attention in recent years. Within this field, the matching process is a key question for connecting this formalism with precise UV theories beyond the Standard Model. It is precisely here where functional methods have emerged as very effective tools, especially for automating computations.

So far, this method has been applied up to one loop. I present a systematic procedure for going beyond, considering both fermionic and bosonic degrees of freedom. I will demonstrate how the inclusion of gauge bosons requires a new approach to the problem that was not necessary in the one-loop case. It will rely on the introduction of the Wilson line to obtain a covariant expansion.

Additionally, this method will be exemplifyed with the matching of QED to the Euler-Heisenberg Lagrangian

Speaker: Mr ADRIÁN Moreno Sánchez (Universidad de Granada)

Functional Matching at Two Loop Order - Adrian Moreno.pdf

15:30 Mapping the SMEFT one-loop structure of linear Standard Model extensions

This talk will present a one-loop UV/IR dictionary providing a mapping between the $B$-conserving dimension-6 SMEFT and the linear SM extensions. These are exotic multiplets that couple linearly to the SM through renormalisable interactions. Our work leverages recent progress in computational tools which automate the one-loop matching procedure. The utility of our map in assessing the implications of dimension-6 operator measurements on simplified models and vice versa is illustrated with an example model interpretation of a fit to electroweak precision data.

Speaker: John Gargalionis (IFIC)

Gargalionis.pdf

15:50 Mapping the SMEFT onto BSM models

While the matching of specific new physics scenarios onto the SMEFT framework is a well-understood procedure, the inverse problem, going from the SMEFT to UV scenarios, is more involved and requires the development of new methods to perform a systematic exploration of models. In this talk, I will discuss a diagrammatic approach to construct in an automated way a complete set of possible BSM models, given a certain set of well specified assumptions, that can reproduce specific patterns of SMEFT operators, and illustrate its use by generating models with no tree-level contributions to four-fermion operators. These class of models, which on the SMEFT only contribute to four-fermion operators at one-loop order, can contain relatively light particles that could be discovered at the LHC in direct searches, and even accommodate a dark matter candidate. In these scenarios, there is an interesting interplay between indirect SMEFT and direct searches, combining low-energy observables with the SMEFT Higgs-fermion analyses and searches for resonances at the LHC.

Speaker: Dr Ricardo Cepedello (Universidad de Granada)

Mapping_SMEFT.pdf

14:30 → 16:10 Parallel Session PI.2

Convener: João Penedo

14:30 Quadratic Coupling of Axions to Photons

Using chiral perturbation theory as a guideline, we show that the QCD axion couples to the electromagnetic (EM) kinetic term at one loop, generating a shift-breaking effective operator $a^2F_{\mu\nu}F^{\mu\nu}$. If axions make up dark matter, they induce some temporal variation of the EM-fine structure constant $\alpha$, which is severely constrained. Therefore, we can exploit the precision of upcoming quantum metrology experiments to probe the signal of axion dark matter. We recast these constraints on the QCD axion parameter space. Finally, we discuss how to generalise our finding to axion-like particles (ALPs), leading to more stringent constraints on the ALPs parameter space.

Reference: arXiv: 2307.10362 (https://arxiv.org/abs/2307.10362)

Speaker: Hoa Vuong (DESY)

QuadraticAxion_Planck2024.pdf

14:50 Flavour-Invariant Contributions to the Strong CP Problem

Small instantons can increase the axion mass, due to an appropriate modification of QCD in the ultraviolet (UV), in a way where the axion still solves the strong CP problem. However, if any CP violation is present in UV theories which enhance small instantons, the minimum of the axion potential will be shifted, destroying the axion solution strong CP problem. In this talk, I will first introduce the use of flavour invariants to capture CP violation in the Standard Model Effective Field Theory (SMEFT). I will then show that these CP-breaking SMEFT flavour invariants naturally arise in the instanton computation of the shifted minimum of the axion potential. Finally, I will present how the invariants can be used to make statements about the way CP-violating SMEFT operators can enter in instanton computations and how the invariants provide a classification of the leading effects of all possible SMEFT operators.

Speaker: Jonathan Kley (DESY)

Planck2024_Kley.pdf

15:10 ALP contribution to the Strong CP problem

We compute the one-loop contribution to the $\bar{\theta}$-parameter of an axion-like particle (ALP) with CP-odd derivative couplings. Its contribution to the neutron electric dipole moment is shown to be orders of magnitude larger than that stemming from the one-loop ALP contributions to the up- and down-quark electric and chromoelectric dipole moments. This strongly improves existing bounds on ALP-fermion CP-odd interactions, and also sets limits on previously unconstrained couplings. The case of a general singlet scalar is analyzed as well. In addition, we explore how the bounds are modified in the presence of a Peccei-Quinn symmetry.

Speaker: Mr Victor Enguita Vileta

planck-2024-talk_v2.pdf

15:30 A Minimal Solution to the Strong CP Problem

I propose a solution to the Strong CP problem, based on an underlying CP symmetry and a flavor symmetry. Requiring the Standard Model to have more than one Higgs doublet and softly breaking CP and the flavor symmetry only in the scalar sector, allows to recover the CP violating phase in the quark mass matrix without generating a large strong CP angle. I show that this conclusion holds at higher orders and discuss the profound consequences for flavor.

Speaker: Claudio Andrea Manzari (UC Berkeley & LBNL)

Manzari_Talk.pdf

15:50 Axion paradigm with "coloured" neutrino masses

I will discuss our recent paper Phys.Rev.Lett. 132 (2024) 5, 051801, where we propose a generalized KSVZ-type axion framework in which coloured fermions and scalars act as two-loop Majorana neutrino-mass mediators. The global Peccei-Quinn symmetry under which exotic fermions are charged solves the strong CP problem. Within our general proposal, various setups can be distinguished by probing the axion-to-photon coupling at helioscopes and haloscopes. We also comment on axion dark-matter production in the early Universe.

Speaker: Henrique Brito Câmara (CFTP/IST, U. Lisboa)

HBCâmara_PLANCK_2024_Talk.pdf

14:30 → 16:10 Parallel Session PI.3

Convener: Stefan Antusch

14:30 Probing Gravitational Waves Using Neutrino Flavor Oscillations

Gravitational waves can affect neutrino oscillation probabilities and
may hence be detectable at neutrino telescopes. We propose a heuristic
model describing the influence of gravitational waves on the propagation
and flavor oscillations of neutrino wave packets.
This model is based on the assumption that at lowest order in the
metric perturbation caused by the gravitational wave only the average
propagation distance of the neutrino system is affected. In combination
with an averaging procedure over the time of data taking of the neutrino
experiment this leads to a damping of the neutrino flavor oscillations, if
certain criteria are met.
Therefore, considering the imprints of gravitational waves in the flavor
transition probabilities of high energy neutrinos from pulsars located in
our Galaxy might pave the way for new discoveries in the quickly expanding
field of multi-messenger astronomy.

Speaker: Mr Dominik Hellmann (Technische Universität Dortmund)

hellmann.pdf

14:50 Neutrino masses and Dark Matter from TeV-scale dark confinement

The smallness of neutrino masses in the inverse seesaw mechanism arises due to the interplay of TeV-scale Pseudo-Dirac mass terms and a small explicit breaking of lepton number. Here we propose to use dynamical symmetry breaking from a confining dark non-abelian symmetry to explain such a small lepton-number breaking mass. We couple a single generation of vector-like dark quarks, transforming under a $\text{SU}(3)_\text{D}$ gauge symmetry, to a real singlet scalar, which communicates the dark quark condensate to three generations of heavy neutrinos. The lightest dark baryon is stabilized at the renormalizable level by an accidental dark baryon number symmetry and can account for the observed relic density. This model may be probed by next generation neutrino telescopes via neutrino lines produced from dark matter annihilations.

Speaker: giacomo landini (CSIC-IFIC)

Planck Talk GOOD.pdf

15:10 Unraveling Dark Matter and neutrino mysteries with a scotogenic approach

In this study conducted under a freeze-out scenario, we examine a scotogenic model that tackles the dark matter problem while simultaneously producing three non-zero neutrino masses. Our investigation delves into the dual nature of a dark matter candidate, manifesting from distinct particle components across various energy regimes within the HL-LHC energy range. The results shed light on the behavior of the dark matter candidate in diverse energy contexts, emphasizing correlations with neutrino masses. Additionally, we carefully consider experimental constraints, with a specific focus on lepton flavor-violating observables, providing a comprehensive overview of the model's implications for advancing our understanding of fundamental particles within the freeze-out framework.

Speaker: Ugo DE NOYERS (LAPTh / Université Savoie Mont Blanc)

de Noyers Planck.pdf

15:30 From Dark Matter to Neutrino Masses via a Late Phase Transition

We present a model which addresses two open questions of the Standard Model (SM): the origin of neutrino masses and the nature of dark matter. To achieve this, the SM is extended by two keV-mass right-handed neutrinos as well as a Froggatt-Nielsen-like mechanism, under which only the non-SM fields are charged.

The sterile neutrinos form a 2-component dark matter candidate. We assume the mass term of the new flavon-like scalar field $S$ to be negative, but a non-minimal coupling to curvature causes the effective mass to become tachyonic only in the recent universe, which triggers a late phase transition.

Throughout the early universe and before the phase transition, the left-handed neutrinos are massless. Then, the non-zero expectation value $\langle S \rangle $ leads to small effective neutrino Yukawa couplings and a seesaw mechanism becomes efficient which results in two active neutrinos getting masses, while the third remains massless. The phase transition proceeds slowly, and the changing $\langle S \rangle$ introduces a time dependence to neutrino masses and mixings with potentially interesting phenomenological consequences. Additionally, $S$ can potentially act as thawing quintessence therefore solving another puzzle of the SM.

Speaker: Maya Hager (Max-Planck-Institut für Kernphysik)

Planck_MayaHager.pdf

15:50 Freeze-in at stronger coupling

In this talk, I will discuss the freeze-in dark matter production mechanism at low reheating temperatures. The process is Boltzmann-suppressed if the dark matter mass is above the reheating temperature, and, in this case, the coupling to the thermal bath has to be significant to account for the observed dark matter relic density. As a result, the direct DM detection experiments can already probe such freeze-in models, excluding significant parts of parameter space. The forthcoming experiments will explore this framework further, extending to lower couplings and higher reheating temperatures.

Speaker: Catarina Cosme (U. Coimbra)

Planck2024_CCosme.pdf

14:30 → 16:10 Parallel Session PI.4

Convener: Yifan Chen

14:30 CMB hotspots from tachyonic instability of the Higgs potential

At high energies, such as during inflation, the quartic coupling of the Standard Model (SM) Higgs potential runs negative, according to current measurements. This can lead the potential into a tachyonic regime, where the square of the mass of the SM Higgs becomes negative. This tachyonic instability can exponentially enhance Higgs particle production via Hubble-induced effects and via the dynamics of the Higgs field itself. Furthermore the enhanced Higgs particle production can draw energy out of the Higgs field and produce stabilizing thermal corrections.

The early produced Higgs particles would then modify the curvature perturbations of the early universe which in turn can cause hot or cold spots on the cosmic microwave background (CMB).
The aim of our work is to look into this enhanced Higgs particle production and calculate the temperature of the CMB hotspots, as well as looking into CMB hotspots from other sources such as primordial black holes.

Speaker: Julia Ziegler (Hamburg University)

tachyonic_15_plus_5_v_02.pdf

14:50 Higgs Vacuum Stability during Kination

It is well known that a non-minimal interaction between the Standard-Model Higgs and spacetime curvature can help stabilising the Higgs at high energies, thus avoiding the problem of electroweak vacuum stability during inflation. However, the same non-minimal coupling can be responsible for driving the Higgs close to the instability scale during a post-inflationary phase of kinetic-energy domination, aka kination, due to a change in sign of the Ricci scalar. The Higgs can potentially overcome the barrier in the effective potential that separates the false electroweak vacuum from the true vacuum at super-Planckian field values, with catastrophic consequences.

In this talk, I will discuss how avoiding such instability during kination sets constraints on cosmological observables (the inflationary scale) and on the parameters of the standard model (top quark mass) alike. Interestingly, the mere existence of a barrier between the two vacua is enough to guarantee the stability of the Standard-Model vacuum. Because of the copious tachyonic production of Higgs particles triggered by the change in sign of the Ricci scalar, the Higgs itself can be tasked with (re)heating the Universe after inflation, setting an additional lower bound on the inflationary scale. Smaller top-quark masses are generally favoured, as they allow for higher inflationary scales and higher (re)heating temperatures.

Speaker: Giorgio Laverda

presentation_PLANCK_2024_laverda.pdf

15:10 Curvature Perturbations Protected Against One Loop

I examine one-loop corrections from small-scale curvature perturbations to the superhorizon-limit ones in single-field inflation models, which have recently caused controversy. I consider the case where the Universe experiences transitions of slow-roll (SR) → intermediate period → SR. The intermediate period can be an ultra-slow-roll period or a resonant amplification period, either of which enhances small-scale curvature perturbations. I assume that the superhorizon curvature perturbations are conserved at least during each of the SR periods. Within this framework, I show that the superhorizon curvature perturbations during the first and the second SR periods coincide at one-loop level in the slow-roll limit.

Speaker: Keisuke Inomata (Jonhs Hopkins University)

planck2024_lisbon_june_4_inomata_pdf.pdf

15:30 Natural Metric-Affine Inflation

We study natural inflation in the low energy (two-derivative) metric-affine theory containing only the minimal degrees of freedom in the inflationary sector, i.e. the massless graviton and the pseudo-Nambu-Goldstone boson (PNGB). This theory contains the Ricci-like and parity-odd Holst invariants together with non-minimal couplings between the PNGB and the above-mentioned invariants. The Palatini and Einstein-Cartan realizations of natural inflation are particular cases of our construction. Explicit models of this type are shown to admit an explicit UV completion in a QCD-like theory with a Planckian confining scale. Moreover, for these models, we find regions of the parameter space where the inflationary predictions agree with the most recent observations at the $2\sigma$ level. We find that in order to enter the $1\sigma$ region it is necessary (and sufficient) to have a finite value of the Barbero-Immirzi parameter and a sizable non-minimal coupling between the inflaton and the Holst invariant (with sign opposite to the Barbero-Immirzi parameter). Indeed, in this case the potential of the canonically normalized inflaton develops a plateau as shown analytically.

Speaker: Antonio Racioppi (National Institute of Chemical Physics and Biophysics (EE))

Racioppi_Lisbon.pdf

15:50 Oscillons in Higgs Inflation

Higgs inflation stands out among many possible inflationary models for its minimal character, not requiring any extra degrees of freedom beyond the Standard Model. Nonetheless, the inflationary predictions, as well as the post-inflationary dynamics, are sensitive to the formulation of gravity one uses.

In this work, we study the preheating phase of Higgs Inflation in Einstein-Cartan gravity.
Focusing for concreteness on a simplified scenario involving the seminal Nieh-Yan term, we explicitly show the formation of dense and spatially localized oscillon configurations constituting up to 70% of the total energy density.
The emergence of these meta-stable objects may lead to a prolonged period of matter domination, effectively modifying the post-inflationary history of the Universe as compared to the metric and Palatini counterparts.
Notably, the creation of oscillons comes together with a significant gravitational wave signal, whose typical frequency lies, however, beyond the range accessible by existing and planned gravitational wave experiments. The impact of the Standard Model gauge bosons and fermions and the potential extension of our results to more general Einstein-Cartan settings are also discussed.

Speaker: Matteo Piani (CENTRA, Instituto Superior Técnico, Universidade de Lisboa)

Oscillons in Higgs Inflation (Matteo Piani).pdf

16:10 → 16:40 Coffee break

16:40 → 19:00 Parallel Session PI.5

Convener: Ivo de Medeiros Varzielas (CFTP, IST, University of Lisbon)

16:40 Proton decay, a fresh look into their RG effects and possible UV models

I will discuss an agnostic, model-independent analysis of baryon number violation using the power of Effective Field Theory. In my presentation, I show the contribution of dimension six and seven effective operators to ∣Δ(B−L)∣=0, 2 nucleon decays taking into account the effects of Renormalisation Group Evolution and we will find lower limits on the energy scale of each operator and correlations between different decay modes. Furthermore, I will also discuss possible UV theories responsible for the phenomena of proton decay and/or (Majorana) neutrino masses and the implications on the masses of the particles in the UV.

Speaker: Arnau Bas i Beneito (Universitat de València (UV, IFIC))

BasiBeneito_PLANCK2024.pdf

17:00 Global LFV constraints on EFTs

We present a new global analysis of the charged lepton flavor violating sector of low-energy and SM effective field theories, performing a global fit beyond the most common consideration of one operator at a time. We investigate how much present data is able to constrain the full parameter space, inspecting the potential flat directions that hinder this task, and discuss how the bounds dramatically change when considering a global picture.

Speaker: Xabier Marcano (UAM-IFT)

Planck24_xmarcano.pdf

17:20 Renormalization group equations of a general effective field theory

The RGEs of a generic renormalizable model have been known for a long time, up to two loops and beyond. Similar results exist for a generic softly broken supersymmetric model. The usefulness of these well-known equations hinges on the fact that the relevant loop calculations are done once and for all, so that in order to get the RGEs of a specific model one only needs to perform some algebra with tensors. In this talk, I will discuss the idea of extending these results to operators beyond dimension four.

Speaker: Renato Fonseca (University of Granada)

Renato-Fonseca-Planck2024.pdf

17:40 Gaussian Formalism: From Hesenberg's Uncertainty Principle to Time-Boundary Effect and Lorentz-Covariant Complete Basis for Spinors

This talk provides an overview of Gaussian formalism and its diverse applications. We will explore Heisenberg's uncertainty principle within the framework of quantum information theory. Additionally, we will examine the Time-Boundary Effect in quantum field theory and its significance in resolving isospin anomalies in vector-meson decay. The development of a Lorentz-covariant complete basis for spinors will also be briefly discussed.

Speaker: Kin-ya Oda (Osaka University)

odakin_Planck2024.pdf

18:00 No talks - Room booked for another event

16:40 → 19:00 Parallel Session PI.6

Convener: Juan A. Aguilar-Saavedra

16:40 Precise Estimation of Charged Higgsino/Wino Decay Rates and Implications for Collider Searches

Electroweakly interacting massive particles are strong candidates for
dark matter and are included in various new physics models. For example,
Higgsinos and Winos are leading dark matter candidates in supersymmetry
models. A major characteristic of such dark matter is that there are
slightly heavier isospin partner particles in addition to the dark
matter itself. These particles are metastable and eventually decay into
dark matter, but they produce signals such as charged tracks and
displaced vertices, playing a significant role in the search at
colliders like the LHC. The decay modes and lifetimes of these heavier
particles are crucial for the collider search for dark matter. In this
talk, I will discuss the precise calculations of these decay rates,
including quantum corrections, and the impacts of these results on
collider searches.

Speaker: Satoshi Shirai (Kavli IPMU)

Planck2024.pdf

17:00 Measuring spin correlations of bottom and charm quark pairs at the LHC

Spin correlations have been studied in detail for top quarks at the LHC, but have not yet been explored for the other flavors of quarks. Utilizing the partial preservation of the quark spin information in baryons in the jet produced by the quark, we present possible analysis strategies for ATLAS and CMS to measure the spin correlations in $b\bar b$ and $c\bar c$ samples. We find that some measurements are feasible with existing datasets while others will become possible at the HL-LHC. The proposed measurements will provide new information on the polarization transfer from quarks to baryons and might even be sensitive to physics beyond the Standard Model.

Speaker: Yevgeny Kats (Ben-Gurion University)

Kats PLANCK 2024.pdf

17:20 $S$-wave contribution to rare $D^0 \to \pi^+ \pi^- \ell^+ \ell^-$ decays in the Standard Model and sensitivity to New Physics

Physics of the up-type flavour offers unique possibilities of testing the Standard Model (SM) compared to the down-type flavour sector. Here, I discuss SM and New Physics (NP) contributions to the rare charm-meson decay $ D^0 \to \pi^+ \pi^- \ell^+ \ell^- $. In particular, I discuss the effect of including the lightest scalar isoscalar resonance in the SM picture, namely, the $f_0 (500)$, which manifests in a big portion of the allowed phase space. Other than showing in the total branching ratio at an observable level of about $ 20\% $, the $f_0 (500)$ resonance manifests as interference terms with the vector resonances, such as at high invariant mass of the leptonic pair in distinct angular observables. Recent data from LHCb optimize the sensitivity to $P$-wave contributions, that I analyse in view of the inclusion of vector resonances. I propose the measurement of alternative observables which are sensitive to the $S$-wave and are straightforward to implement experimentally. This leads to a new set of null observables, that vanish in the SM due to its gauge and flavour structures. Finally, I study observables that depend on the SM interference with generic NP contributions from semi-leptonic four-fermion operators in the presence of the $S$-wave.

Speaker: Mr Luiz Vale Silva

Luiz_VALE_SILVA_v6_short.pdf

17:40 Measuring lepton number violation at colliders

Seesaw extensions of the Standard Model explain the observed neutrino masses by introducing right-handed neutrinos with lepton number violating (LNV) interactions. In order for the neutrinos to be collider-detectable they must form almost mass-degenerate pseudo-Dirac pairs. Their tiny mass splitting leads to heavy neutrino-antineutrino oscillations. A measurement of these oscillations can be utilised to determine the amount of LNV introduced by the seesaw. I present minimal viable models and evaluate the potential of current and future collider experiments to observe LNV.

Speaker: Jan Hajer (CFTP, IST, Universidade de Lisboa)

Measuring lepton number violation at colliders

18:00 Minimal Dark Matter Search at Muon Collider

Minimal dark matter is one of the most motivated dark matter candidates, and many analyses at collider experiments for this model have been discussed. In our work, we considered the search for minimal dark matter at future high-energy muon collider experiments, in particular the $\mu^+$$\mu^+$ collider experiment. We found that the indirect search, which measures the quantum correction to the muon elastic scattering, is much more sensitive than the direct search. We also discussed the usefulness of the polarised muon beam in this search.

Speaker: Mr Atsuya Niki (University of Tokyo)

planck2024_niki.pdf

18:20 Hunting for Charged Resonances and Minimal Dark Matter at a Muon Collider

A multi-TeV muon collider would be very efficient not only for the search for new heavy neutral particles, but also for the discovery of charged bosons of the W′ type. We find that, by analyzing the associated production with a Standard Model W, charged resonances can be probed directly up to multi-TeV mass values close to the collision energy, and for very small couplings with the SM fermions, marking an unprecedented level of sensitivity for a direct search. Furthermore, the channel offers a very efficient and alternative way to probe the WIMP scenario for the very special and compelling case of Minimal Dark Matter (MDM) in the 5-plet EW representation, by allowing the direct detection of the charged component of the MDM bound state. The reach on the WIMP 5-plet thermal target is found to be much higher than those of mono-X, missing-mass and disappearing tracks signatures.

Speaker: Natascia Vignaroli

Vignaroli-planck2024.pdf

18:40 Imprints of new physics phenomena: from collider to gravitational waves observables

Despite the tremendous success of the Standard Model (SM) with its properties remarkably well measured, there is overwhelming phenomenological evidence that strongly suggests the need for physics beyond the current SM, such as explanations for dark matter and neutrino masses. In this presentation we will discuss LISA's potential to reveal further evidence of new physics phenomena through upcoming measurements of the Stochastic Gravitational Wave Background (SGWB) generated from strong first-order phase transitions in the early Universe. As benchmark scenarios, we examine:
1) Colour symmetry restoration at low temperatures within a framework featuring two scalar leptoquarks with thermal vacuum expectation values (VEVs).
2) The impact of supercooling in abelian extensions of the SM governed by classical scale invariance.
3) Phase transitions occurring within a non-abelian dark sector.
Specifically, we explore the conditions that allow these scenarios to be probed at LISA and discuss the potential consequences for collider physics observables. This includes the trilinear Higgs coupling, mixing angles and the mass of new particles.

Speaker: António Morais (University of Aveiro)

Morais.pdf

16:40 → 19:00 Parallel Session PI.7

Convener: Igor Ivanov

16:40 A model of pseudo-Nambu–Goldstone dark matter with two complex scalars

Within the WIMP paradigm, a Higgs-portal DM that interacts with SM particles through Higgs-portal interaction is a simple and testable scenario. On the other hand, such models are severely constrained by DM direct detection experiments. It is not easy to avoid the constraint maintaining the correct DM relic abundance unless the DM mass is fine-tuned to be around the resonance. Recently, pseudo-Nambu-Goldstone DM (pNG DM) has been proposed to cure this double bind. It has an interesting property that it can easily suppresse the spin-independent cross section with nucleon in the direct detection experiments keeping the DM abundance thanks to the low-energy theorem. In this talk we propose a new pNG DM model consisting of two SM-singlet complex scalars charged under dark U(1) gauge symmetry, which easily evades all existing constraints and explains the DM abundance by freeze-out mechanism. Our model contains several merits compared to the original pNG DM model and other variants; no domain-wall problem, no Landau pole, and DM is absolutely stabilized by Z2 symemtry.

Speaker: Dr Yu Hamada (DESY)

planck24_hamada.pdf

17:00 A model of two dark matter candidates with equal abundance

We consider a model with two inert scalars, originating two dark matter (DM) particles. We identify the criteria ensuring that the inert vacuum is the global minimum. While taking into account all the theoretical and current experimental constraints, we find unexplored regions of parameter space where the two DM candidates contribute equally to the experimental relic density.

Speaker: Rafael Filipe Teixeira Boto (Instituto Superior Técnico)

Boto_PLANCK.pdf

17:20 $U(1)$-charged Dark Matter in three-Higgs-doublet models

We explore three-Higgs-doublet models that may accommodate scalar Dark Matter where the stability is based on an unbroken $U(1)$-based symmetry, rather than the familiar $\mathbb{Z}_2$ symmetry. We try to classify all possible ways of embedding a $U(1)$ symmetry in a three-Higgs-doublet model. The class of such models is presented and models are compared. These models all contain mass-degenerate pairs of Dark Matter candidates, due to the $U(1)$ symmetry unbroken (conserved) by the vacuum. The pairs can be seen as one even and one odd, under CP, or, in a different basis, as having opposite charges under $U(1)$. Most of these models preserve CP. Three of the discussed models have not been considered before in the literature, which reminds us that there are still many aspects to consider in the three-Higgs-doublet models. Such classification and identification of models is useful for model builders interested in the three-Higgs-doublet models stabilised by continuous symmetries. Apart from classifying the Dark Matter candidates, we perform a numerical check of the $U(1) \otimes U(1)$-symmetric 3HDM, which is the most general phase-invariant three-Higgs-doublet model.

Speaker: Anton Kunčinas (CFTP/IST, U. Lisboa)

Kuncinas_U1-DM.pdf

17:40 Astrophysical Phenomenology of Colored Higgs Triplet

The color-triplet partner of the Higgs doublet is a model-independent prediction of grand unification.
It has been shown some time ago that this particle can be much lighter than the GUT scale, all the way
to TeV mass range, and correspondingly very long lived. In this presentation we concentrate on a stable $(\tau > t_{universe})$
triplet and investigate its astrophysical and phenomenological implications. In particular, we explore the possibility that
their color-singlet bound states with ordinary quarks can be dark matter. We discuss how the triplet affects the history of
our universe and where it might hide today (core of planet/stars or daily-life matter).

Speaker: Anna Jankowsky (University of Munich (LMU))

Colored_Triplet_Pheno_PLANCK2024-6.pdf

18:00 No talks - Room booked for another event

16:40 → 19:00 Parallel Session PI.8

Convener: Javier Rubio

16:40 Shedding light on the $\Delta m^2_{21}$ tension with supernova neutrinos

One long-standing tension in the determination of neutrino parameters is the mismatched value of the solar mass square difference, $\Delta m_{21}^2$, measured by different experiments: the reactor antineutrino experiment KamLAND finds a best fit larger than the one obtained with solar neutrino data. Even if the current tension is mild ($\sim 1.5\sigma$), it is timely to explore if independent measurements could help in either closing or reassessing this issue. In this regard, we explore how a future supernova burst in our galaxy could be used to determine $\Delta m_{21}^2$ at the future Hyper-Kamiokande detector, and how this could contribute to the current situation. We study Earth matter effects for different models of supernova neutrino spectra and supernova orientations. We find that, if supernova neutrino data prefers the KamLAND best fit for $\Delta m_{21}^2$, an uncertainty similar to the current KamLAND one could be achieved. On the contrary, if it prefers the solar neutrino data best fit, the current tension with KamLAND results could grow to a significance larger than $5\sigma$. Furthermore, supernova neutrinos could significantly contribute to reducing the uncertainty on $\sin^2\theta_{12}$.

Speaker: Rasmi Muñoz

Rasmi Munoz PLANCK 2024.pdf

17:00 Geometric (p)reheating of the Universe

We study the energy transfer after inflation from the inflaton ($\phi$) into a scalar field ($\chi$) non-minimally coupled to gravity via $\xi R|\chi|^2$, considering single field inflationary models with potential $\propto |\phi|^{p}$ around $\phi = 0$. This corresponds to the paradigm of geometric preheating, which we extend to its non linear regime by means of lattice simulations. Using $\alpha$-attractor T-model potentials as a proxy, we study the dynamics of the system for $p=2, 4, 6$, and determine whether energetic dominance of $\chi$ over $\phi$ (i.e.~proper reheating) can be achieved, depending on the inflationary energy scale $\Lambda$. While reheating is frustrated for $p = 2$, it can be partially achieved for $p = 4$, and it becomes very efficient for $p = 6$. In the latter case we determine the energy and time scales of reheating as a function of $\xi$ and $\Lambda$, and highlight that contrary to other scenarios, the uncovered mechanism enables full reheating via non-perturbative particle production at arbitrarily low energy scales. Furthermore, we point out that due to the non-linear dynamics, a large gravitational wave background is to be expected, peaked at frequencies accessible to current/planned detectors for sufficiently low $\Lambda$.

Speaker: Nicolás Loayza (IFIC - Universitat de Valéncia - CSIC)

Planck24_Loayza.pdf

17:20 Energy distribution and equation of state during and after tachyonic preheating

We discuss the evolution of the energy distribution and equation of state during the reheating phase. We consider observationally consistent single-field inflation models, with potentials that have monomial shape around the origin and a reheating sector that comprises a massless scalar field, which couples via a trilinear interaction to the inflaton. By investigating the non-linear dynamics of these systems with the help of lattice simulations, we are able to trace back the evolution of the fields during the early preheating stage, and eventually reconstruct the whole phase of reheating. This allows us to determine the exact number of e-folds that are required to reheat the universe, such that we can reduce the uncertainty of the predictions of the spectral tilt and tensor-to-scalar ratio substantially.

Speaker: Kenneth Marschall

Energy distribution and equation of state during and after tachyonic preheating.pdf

17:40 Emergent particles of a de Sitter universe: Thermal interpretation of the stochastic formalism and beyond

A thermal interpretation of the stochastic formalism of a slow-rolling scalar field in a de Sitter (dS) universe is given. We construct a correspondence between causal patches in the 3-dimensional space of a dS universe and particles living in an abstract space. By assuming a dual description of scalar fields and classical mechanics in the abstract space, we show that the stochastic evolution of the infrared part of the field is equivalent to the Brownian motion in the abstract space filled with a heat bath of massless particles. The 1st slow-roll condition and the Hubble expansion are also reinterpreted in the abstract space as the speed of light and a transfer of conserved energy, respectively. Inspired by this, we sketch the quantum emergent particles, which may realize the Hubble expansion by an exponential particle production. This gives another meaning of dS entropy as entropy per Hubble volume in the global dS universe.

Speaker: Dr TaeHun Kim (KIAS)

TaeHun_Kim.pdf

18:00 Probing Reheating with Graviton Bremsstrahlung

In this talk, I will discuss the inevitable stochastic gravitational wave (GW) spectrum resulting from graviton bremsstrahlung during inflationary reheating. We will focus on an inflaton, denoted as $\phi$, oscillating around a generic monomial potential $V(\phi) \propto \phi^n$, while considering two different reheating scenarios: (i) inflaton decay and (ii) inflaton annihilation. I will demonstrate the intriguing dependence of GW on the shape of the inflaton potential as well as the type of inflaton-matter coupling. Finally, I will highlight the novel potential of future high-frequency GW detectors in probing the dynamics of reheating.

Speaker: Dr Yong Xu (JGU Mainz)

Planck24_Xu.pdf

18:20 Black Hole Quadratic Quasi-Normal Modes

We study the quadratic quasi-normal modes of a Schwarzschild black hole, i.e. those perturbations that originate from the coupling of two (linear) quasi-normal modes.
Assuming the amplitude of the two linear modes is known, we compute the amplitude of the resulting quadratic mode for a wide range of possible angular momenta. Finally, we reconstruct the waveform in radiation gauge.

Speaker: Bruno Bucciotti (Scuola Normale Superiore di Pisa)

Bucciotti.pdf

18:40 Nonlocal field theories and nonlocal gravitational models

Nonlocal field theories allow us to formulate a quantum renormalizable theory of the gravitational field, thanks to an improved ultraviolet convergence of the quantum propagator. In this talk, I will describe the main features of these models, such as renormalizability and quantum unitarity. Additionally, I will discuss some properties of classical solutions of the modified Einstein's equations.

Speaker: Fabio Briscese

Briscese_Planck2024.pdf

Wednesday 5 June

09:30 → 10:00 The Path Towards the Future Circular Collider at CERN.

TBA

Speaker: Emmanuel Tsesmelis (CERN)

Tsesmelis PLANCK2024.pdf

10:00 → 10:30 Searches for Long Lived Particles

TBA

Speaker: James Beacham (Duke University (US))

Beacham_LLPs_PLANCK2024_Lisbon_2024June5.pdf

10:30 → 11:00 Coffee Break

11:00 → 11:30 Gravitational Vector Dark Matter

TBA

Speaker: Bohdan Grzadkowski

Grzadkowski_Planck24_v2.pdf

11:30 → 12:00 Generalized BGL 2HDM models

TBA

Speaker: francisco j. botella (University of Valencia)

botella_1.pdf

12:00 → 12:30 Flavor-nondiagonal neutral Higgs Yukawa couplings revisited

TBA

Speaker: Howard Haber (University of California,Santa Cruz (US))

Haber_Revisit.pdf

12:30 → 14:30 Lunch

17:00 → 19:10 Boat Trip

19:30 → 23:00 Conference Dinner

Thursday 6 June

09:30 → 10:00 Yukawa couplings at infinite distance

TBA

Speaker: Luis E. Ibañez

Ibanez.pdf

10:00 → 10:30 Dark Matter Production from Oscillations

TBA

Speaker: Joshua Thomas Ruderman

PlanckROMP.pdf

10:30 → 11:00 Coffee Break

11:00 → 11:30 Dark matter on dark branes

TBA

Speaker: Stefan Pokorski

Pokorski.pdf

11:30 → 12:00 Landscape, swampland and extra dimensions

TBA

Speaker: Ignatios Antoniadis (UPMC)

12:00 → 12:30 Strong Gravity Frontier of Particle Physics

TBA

Speaker: Yifan Chen

PLANCK24_6June24.pdf

12:30 → 14:30 Lunch Break

14:30 → 16:10 Parallel Session PII.1

Convener: Fabio Briscese

14:30 Ultra-high frequency GW backgrounds from cosmic strings

This talk focuses on gravitational-wave backgrounds (GWB) from cosmic strings that would manifest only at ultra-high frequencies (above kilohertz), that leave no signal at either LIGO, Einstein Telescope, or LISA, and correspond to high-energy scale (beyond $10^{10}$ GeV) particle physics parameters. Signals from metastable local strings, with amplitude as large as the $\Delta N_{\rm eff}$ bounds, offer exciting prospects to probe grand unification physics. Beyond the information of the symmetry-breaking scale, the high-frequency spectrum encodes the microscopic structure of the strings through the position of the UV cutoff. The detection of such cut-off enables the reconstruction of the scalar potential, particularly the scalar self-coupling. We estimate the needed reach of hypothetical futuristic GW detectors to probe such GW and, therefore, the corresponding high-energy physics processes. On the other hand, the GWB from global axionic strings is suppressed even for large symmetry-breaking scales due to the matter era from the associated heavy axions. (Based on 2312.09281)

Speaker: Peera Simakachorn (IFIC, Valencia U.)

Planck2024_Peera.pdf

14:50 Type II seesaw: vacuum stability, phase transitionsand gravitational waves

Type II seesaw provides an attractive way to account for the observed light neutrino masses by adding a scalar triplet to the Standard Model. Due to a larger scalar sector, the vacuum structure of the model is richer and first-order phase transitions become available. We study (meta)stability of the electroweak vacuum, cosmic phase transitions and gravitational waves in the type II seesaw model. We find that there are no `panic' vacua for realistic parameter space, but there is parameter space where electroweak vacuum is unstable.

Speaker: Aleksei Kubarski

Planck2024_Kubarski.pdf

15:10 Dark linear seesaw mechanism

I will discuss our recent paper Phys.Lett.B 843 (2023) 138012 where we propose a minimal model where a dark sector, odd under a Z2 discrete symmetry, is the seed of lepton number violation in the neutrino sector at the loop level, in the context of the linear seesaw mechanism. We study the dark-matter phenomenology of the model, focusing on the case in which the stable particle is the lightest neutral scalar arising from the dark scalar sector. Prospects for testing our framework with the results of current and future lepton flavour violation searches are also discussed.

Speaker: Aditya Batra (CFTP-IST, Lisbon)

Batra.pdf

15:30 Melting domain walls for Pulsar timing arrays

Based on: arxiv 2307.04582

We discuss cosmic domain walls described by a tension redshifting with the expansion of the Universe. These melting domain walls emit gravitational waves with the low-frequency spectral shape corresponding to the spectral index \gamma=3 favored by the recent Pulsar timing data. We discuss a concrete high-energy physics scenario leading to such a melting domain wall network in the early Universe. This scenario involves a feebly coupled scalar field, which can serve as a promising dark matter candidate. We identify parameters of the model that match the gravitational wave characteristics observed in the Pulsar timing data. The dark matter mass is pushed to the ultralight range accessible through planned observations thanks to the effects of the superradiance of rotating black holes.

Speaker: Rome Samanta

Rome_Samanta_Planck24_talk_ppt.pptx

15:50 Model-independent constraints on the QCD axion from supernovae

The QCD axion solves the strong CP problem and is one of the most searched for DM candidates. As of today, astrophysical observations, such as neutron star cooling and energy loss from supernovae, place the strongest bounds.
This bound generally depends on the specific QCD axion model under consideration. However, it also depends on couplings that are model-independent and still present when all the model-dependent couplings are tuned away, as in the case of the so-called astrophobic axion.
In my talk, I will show the dominant axion production mechanism in a SN considering only model-independent couplings. This will lead to a orders of magnitude stricter bound than in current literature, where the operator responsible for the dominant model independent contribution has been neglected so far. Additionally, I will explore the full non-trivial momentum dependence of the axion-nucleon coupling in zero- and finite-density environments. This dependence is induced by one-loop corrections to the coupling that can be systematically calculated within the framework of chiral perturbation theory, both at zero density and in thermal field theory.

Speaker: Michael Stadlbauer

Presentation_Axion_Planck_2024_final.pdf

14:30 → 16:10 Parallel Session PII.2

Convener: Xabier Marcano (UAM-IFT)

14:30 Unitarity constraints on large multiplets of arbitrary gauge groups

We impose partial-wave unitarity on 2 –> 2 tree-level scattering processes to derive constraints on the dimensions of large scalar and fermionic multiplets of arbitrary gauge groups. We apply our results to various scalar and fermionic extensions of the Standard Model, and also to the Grand Unified Theories (GUTs) based on the groups SU(5), SO(10), and E6. We identify scenarios within the latter two GUTs that violate the unitarity condition — this may require a reevaluation of the validity of perturbation theory in those scenarios.

Speaker: Mr André Milagre (CFTP)

Milagre_PLANCK2024.pdf

14:50 Oblique Parameters in General New Physics Frameworks

The oblique parameters provide a convenient way of comparing the predictions of a New Physics Model with $SU(2) \times U(1)$ as its gauge group with those of the Standard Model (SM). The Beyond the Standard Model (BSM) particle content of these New Physics Models must consist of fermions and/or scalars that should preferably be in the representations of the gauge group such that they cannout couple to the light fermions with which most experiments are performed. In that way, one ensures that the only effects of these BSM particles are through their contributions to the vacuum polarizations. Therefore, the oblique parameters can be used to constrain New Physics Models. In my presentation, I will talk about our results for the oblique parameters in general New Physics frameworks.

Speaker: Francisco Albergaria (CFTP/IST, U. Lisboa)

Albergaria.pdf

15:10 Accidentally Light Scalars from Large Representations

In models with spontaneous symmetry breaking by scalar fields in large group representations, we observe that some of the scalar masses can be loop-suppressed with respect to the naive expectation from symmetry selection rules. We present the most minimal model — the SU(2) five-plet — with such accidentally light scalars, featuring compact tree-level flat directions lifted by radiative corrections. We sketch some applications, from stable relics and slow roll in cosmology, to hierarchy and fine-tuning problems in particle physics.

Speaker: Giacomo Ferrante (LUPM)

Planck_FERRANTE.pdf

15:30 Minimal U(1) two-Higgs-doublet models for quark and lepton flavour

In this talk I will describe the minimal 2HDM with U(1) flavour symmetries which accounts for the observed pattern of quark and lepton masses and mixings. The corresponding phenomenology related to flavour processes in both sectors will also be investigated, as well as the constraints imposed in the parameter space.

Speaker: José Maria Rebelo Rocha

Jose Rocha.pdf

15:50 Spontaneous CP violation and μ−τ symmetry in two-Higgs-doublet models with flavour conservation

In multi-Higgs-doublet models, the simultaneous requirement that (i) CP violation only arises spontaneously, (ii) there are no tree level scalar flavour changing couplings and (iii) the fermion mixing matrix is CP violating, can only be achieved in a very specific way. A general approach on the question is presented stressing new clarifying insights. In the quark sector, that possibility is not viable on phenomenological grounds while in the lepton sector it is highly interesting and leads to viable models with μ−τ symmetric PMNS matrices. Models with Dirac or Majorana (in a type I seesaw scenario) neutrinos, including phenomenological implications, are analysed.

Speaker: Dr Miguel Ruben Nebot Gómez (U. of Valencia - IFIC)

Nebot_Planck2024.pdf

14:30 → 16:10 Parallel Session PII.3

Convener: Ricardo Cepedello (IFIC (CSIC-Univ. Valencia))

14:30 Phenomenology of GeV-scale dark matter near p-wave resonance

We consider a light scalar dark matter candidate with mass in the GeV range whose p-wave annihilation is enhanced through a Breit-Wigner resonance. The annihilation proceeds in the s-channel via a dark photon mediator. We compute the temperature at which kinetic decoupling between dark matter and the primordial plasma occurs and show that including the effect of kinetic decoupling can reduce the dark matter relic density by orders of magnitude. We also find that μ and y-distortions of the CMB spectrum and X-ray data from XMM-Newton strongly constrain the model and rule out the region where the dark matter annihilation cross-section is strongly enhanced at small dispersion velocities. Constraints from direct detection searches and the accelerator limits for dark photons offer complementary probes of the model.

Speaker: Sreemanti Chakraborti (IPPP Durham University)

Planck2024_SC.pdf

14:50 Detecting Hidden Photon Dark Matter Using Superconducting Qubits

Superconducting qubits are one of the most promising candidates for quantum computers and it have been rapidly being developed. We propose to use superconducting qubits for the detection of the hidden photon dark matter of a mass of O(10) μeV. By measuring the excitation of qubits by the dark photon, we find that one can reach 𝜀∼10^-13–10^-12 (where 𝜀 is the kinetic mixing parameter of the hidden photon) with a few tens of seconds using a single standard superconducting qubit. We also propose to construct a quantum circuit to enhance the dark matter signal, which may improve the reach by O(n_q), where n_q is the number of involved qubits.

Speaker: Hajime Fukuda

planck2024.pdf

15:10 Electron Trap as Dark Matter Detector

Ultralight dark matter, such as axion and dark photon, in the milli-eV mass range, is notoriously difficult to detect. It is too high in frequency for high-Q cavity resonators yet below the energy threshold of single-photon detectors. Our recent work (arXiv:2208.06519) showed that the cyclotron motion of trapped electrons can resonantly couple to dark photon and provide a powerful probe of this mass range. The effect is enhanced by the geometric focusing of a spherical cavity. We demonstrated the method is background-free over a 7-day period. I will also present some new ideas for improving this method using excited states and modifying it to search for axion.

Speaker: Mr Samuel S. Y. Wong (Stanford University)

Electron Trap as a Dark Matter Detector PLANCK2024.pdf

15:30 Probing dark matter models with DarkPACK: present state and future developments

Nowadays, the research in Beyond Standard Model (BSM) scenarios aimed at describing the nature of dark matter is a very active field. DarkPACK is a recently released software conceived to help to sudy such models. It can already compute the relic density in the freeze-out scenario, and its potential can be used to compute other observables. With the present contribution, I would like to introduce DarkPACK, its current capabilities and the future perspectives.

Speaker: Marco PALMIOTTO (Institut de physique des deux infinis Lyon, Université Claude Bernard Lyon 1)

presentation_planck24_final.pdf

15:50 Impact of Sommerfeld effect and bound state formation of colored mediators in dark matter studies

Simplified t-channel dark matter models serve as a versatile and well-motivated framework for rich dark sectors that are widely studied by ongoing experimental and theoretical efforts. In this work, we investigate the impact of non-perturbative effects on the dark matter relic abundance for two representative models of this kind of models, focusing on regions of parameter space where coannihilations of colored mediators are important.
In such scenarios, it is well known that the Sommerfeld enhancement and bound state formation processes can significantly alter the predictions for the model parameters of the dark matter candidate.
Besides including the effects stated above, we take into account the effects of excited states beyond the ground state. We will present constraints on models with fermionic and scalar mediators, highlighting the differences and common features of these two.
Moreover, we introduce code that seamlessly integrates with micrOMEGAs 6.0.3, which can be easily adapted by the user for different models.

Speaker: Martin Napetschnig (Technical University of Munich)

Napetschnig_tchannel_BSF.pdf

14:30 → 16:10 Parallel Session PII.4

Convener: Jan Hajer (CFTP, IST, Universidade de Lisboa)

14:30 Leptonic neutral-current probes in a short-distance DUNE-like setup

Precision measurements of neutrino-electron scattering may provide a viable way to test the non-minimal form of the charged and neutral current weak interactions within a hypothetical near-detector setup for the Deep Underground Neutrino Experiment (DUNE). Although low-statistics, these processes are clean and provide information complementing the results derived from oscillation studies. They could shed light on the scale of neutrino mass generation in low-scale seesaw schemes.

Speaker: Salvador Centelles Chuliá (Max-Planck-Institut für Kernphysik)

Salvador Centelles Chuliá.pdf

14:50 Neutrinoless double beta decay searches with the LEGEND experiment

Neutrinoless double beta (0νββ) decay is an ultra-rare process which could take place only if neutrinos were Majorana fermions, namely if neutrinos were their own antiparticle: if observed, this decay would shed light
on neutrinos’ nature and would be an unambiguous evidence for the existence of some Beyond Standard Model Physics, as it entails a violation of the lepton number by two units. Also, from the study of this decay it would
be possible to give an explanation of the matter-antimatter asymmetry observed in the Universe and to extract information about neutrino masses.
The LEGEND Experiment is designed to search for the neutrinoless double beta decay of 76Ge employing active 76Ge-enriched HPGe detectors; these detectors are operated bare in Liquid Argon (LAr), serving both
as a refrigerant and as a veto for background events; the LAr cryostat itself is immersed in a large volume of water, serving as muon veto.
The first phase of the experiment, LEGEND-200, started taking data in March 2023 at Laboratori Nazionali del Gran Sasso (LNGS) in Italy and is now running in a stable physics data taking regime. With an exposure
of 1 ton yr and a target background index of 2 · 10−4 cts/(keV kg yr) at Qββ = 2039 keV, LEGEND-200 is planned to reach a 3σ discovery sensitivity of 1027 yr. The second phase, LEGEND-1000, will operate 1000 kg
of Germanium and is planned to achieve a 3σ discovery sensitivity beyond 1028 yr with its target background index of 1 · 10−5 cts/(keV kg yr) at Qββ. LEGEND-1000 sensitivity will allow to cover the full inverted mass
ordering region.
In this contribution LEGEND’s physics program will be presented, with a focus on the current status and results of the ongoing experimental campaign.

Speaker: Giovanna Saleh

Planck2024_Saleh.pdf

15:10 HNLs from Heavy ALP decays at Neutrino Facilities

Heavy neutral leptons (HNL) are among the hypothetical ingredients behind nonzero neutrino masses. If sufficiently light, they can be produced and detected in fixed-target-like experiments. We show that if the HNLs belong to a richer -- but rather generic -- dark sector, their production rate can deviate dramatically from expectations associated to the standard-model weak interactions. In this work, we postulate that the dark sector contains an axion-like particle (ALP) that naturally decays into HNLs. Since ALPs mix with the pseudoscalar hadrons, the HNL flux might be predominantly associated to the production of neutral mesons (e.g. \pi^0, \eta) as opposed to charge hadrons (e.g. \pi^{\pm}, K^{\pm}). In this case, the physics responsible for HNL production and decay are not directly related and experiments like DUNE might be sensitive to HNLs that are too weakly coupled to the standard model to be produced via weak interactions, as is generically the case of HNLs that play a direct role in the type-I seesaw mechanism.

Speaker: Asli Abdullahi (Universidad Autónoma de Madrid)

Asli.pdf

15:30 Searching for hints of LNV in rare meson decays

The observation of a lepton-number violating (LNV) process would have far-reaching consequences for our understanding of fundamental physics. It would have implications on the viability of leptogenesis scenarios, and point toward a Majorana nature of neutrinos. In this talk, we will point out the possibility of searching for a hint of LNV in the rare meson decays $K\to\pi+$ invisible and $B\to K(K^*)+$ invisible through detailed measurements of kinematic distributions in the missing energy. Although our main focus is on LNV, we highlight that our framework can also be used to search for other types of new physics. In particular, we show to what extent one can distinguish between new physics contributions from a dark sector and LEFT through dedicated measurements of kinematic distributions only. Finally, we point out that the observation of LNV in rare meson decays would have implications for flavor structures in the UV, and could put high-scale leptogenesis under tension.

Speaker: Martin Mojahed

Planck2024.pdf

15:50 Heavy Neutrino-Antineutrino Oscillations at Colliders

Symmetry protected type I seesaw models have been proposed as an explanation for the small masses of the observed neutrinos. These predict heavy neutral leptons that are organized in pseudo-Dirac pairs, whose mass splitting induces heavy neutrino-antineutrino oscillations. We employ a minimal phenomenological model to discuss the ability of future lepton collider experiments to probe the oscillatory signatures.

Speaker: Mr Bruno M. S. Oliveira (Centro de Física Teórica de Partículas (CFTP), Instituto Superior Técnico (IST), Universidade de Lisboa (UL))

Bruno M. S. Oliveira - Heavy Neutrino-Antineutrino Oscillations at Colliders (PLANCK2024).pdf

16:10 → 16:40 Coffee Break

16:40 → 19:00 Parallel Session PII.5

Convener: António Morais (University of Aveiro)

16:40 Hubble-induced phase transitions as a natural quintesential inflation reheating mechanism

A Hubble-induced phase transition is a natural spontaneous symmetry breaking mechanism allowing for explosive particle production in non-oscillatory models of inflation involving non-minimally coupled spectator fields. I will discuss the impact of this effect on the reheating of the Universe after inflation and its characterization via 3+1-dimensional classical lattice simulations, discussing also interesting phenomenological aspects like the generation of short-lived topological defects and gravitational waves.

Speaker: Dr JAVIER RUBIO (Universidad Complutense de Madrid)

JAVIERRUBIO_PLANCK2024.pdf

17:00 Directional detection of Cosmic-Ray boosted dark matter coming from Galactic center

TBA

Speaker: Dr Keiko Nagao (Okayama University of Science)

Nagao.pdf

17:20 Electroweak Symmetry Restoration in Extended Higgs Sectors via Domain Walls

Domain walls are a type of topological defects that can arise in the
early universe after the spontaneous breaking of a discrete symmetry. This occurs in several beyond Standard Model theories with an
extended Higgs sector such as the Next-to-Two-Higgs-Doublet model
(N2HDM). In this talk I will discuss the domain wall solution related
to the singlet scalar of the N2HDM as well as demonstrate the possibility of restoring the electroweak symmetry in the vicinity of the
domain wall. Such symmetry restoration can have profound implications on the early universe cosmology as the sphaleron rate inside the
domain wall would, in principle, be unsuppressed compared with the
rate outside the wall.

Speaker: Mohamed Younes Sassi (2.Institute for theoretical Physics Hamburg)

PlanckTalkDomainWallsv3.pdf

17:40 Precision Calculations of Effective Potentials and Electroweak Phase Transitions in the Early Universe

We present a detailed study of the precision calculations of higher-order contributions to effective potential with the application of three-dimensional effective field theories (3D EFTs). Our work focuses on the thermodynamic quantification and description of electroweak phase transitions in the early Universe for the complex singlet extended Standard Model (cxSM). In particular, we address the issue of gauge and scale dependences associated with the effective potential, which can lead to ambiguities when calculating thermodynamical quantities from the effective potential. To overcome this issue, we employ the high temperature 3D EFT framework, which provides a robust approach for consistently taking into account the relevant contributions in physical predictions. In addition, we study the ambiguities in commonly used renormalization schemes of the effective potential. The phenomenological implications of our results are discussed.

Speaker: Mr Andrii Dashko (DESY Theory)

PLANCK-2024.pdf

18:00 No talks - Room booked for another event

16:40 → 19:00 Parallel Session PII.6

Convener: Renato Fonseca (University of Granada)

16:40 How to rule out $(g-2)_\mu$ in $U(1)_{L_\mu-L_\tau}$ with White Dwarf Cooling

In recent years, the gauge group $U(1)_{L_\mu-L_\tau}$ has received a lot of attention since it can, in principle, account for the observed excess in the anomalous muon magnetic moment $(g-2)_\mu$, as well as the Hubble tension. Due to unavoidable, loop-induced kinetic mixing with the SM photon and $Z$, the $U(1)_{L_\mu-L_\tau}$ gauge boson $A'$ can contribute to stellar cooling via decays into neutrinos.
In this work, we perform for the first time an ab initio computation of the neutrino emissivities of white dwarf stars due to plasmon decay in a model of gauged $U(1)_{L_\mu-L_\tau}$. Our central finding is that an observation of the early-stage white dwarf neutrino luminosity at the 30% level could exclude (or partially exclude) the remaining allowed parameter space for explaining $(g-2)_\mu$ . In this work, we present the relevant white dwarf sensitivities over the entire $A'$ mass range. In particular, we have performed a rigorous computation of the luminosities in the resonant regime, where the $A'$ mass is comparable to the white dwarf plasma frequencies.

Speaker: Patrick Foldenauer (Instituto de Física Teórica UAM/CSIC Madrid)

foldenauer_planck24.pdf

17:00 New Constraints on Gauged U(1)$_{L_\mu-L_\tau}$ Models via $Z-Z'$ Mixing

It is known that the model based on U(1)$_{L_\mu-L_\tau}$ gauge symmetry can explain not only the discrepancy between the measured value of muon $g-2$ and the theoretical prediction, but also the structure of the neutrino mass and mixings. We revisit the analysis of the mass matrix structure in the minimal U(1)$_{L_\mu-L_\tau}$ models based on the latest experimental result, where the minimal stands for the symmetry breaking caused only by a single scalar field. We find that the model called type ${\bf 2}_{+1}$, where an SU(2)$_L$ doublet scalar $\Phi_{+1}$ with the U(1)$_{L_\mu - L_\tau}$ charge $+1$ and the hypercharge $+1/2$, predicts the $\bf B_3$ texture and is marginally acceptable under the current neutrino oscillation data and cosmological observation. When the U(1)$_{L_\mu - L_\tau}$ gauge symmetry is broken by the vacuum expectation value of the standard model non-singlet representation such as $\Phi_{+1}$, there are additional contributions to the flavor-changing meson decay process and atomic parity violation via the $Z-Z'$ mixing. We newly evaluate the model-dependent constraints on the model and conclude that the type ${\bf 2}_{+1}$ model is robustly ruled out. The model is extended to have an additional vacuum expectation value of a standard model singlet scalar
in order to avoid the stringent constraint from the flavor-changing meson decay. Finally, we find the allowed range of the ratio of these vacuum expectation values.

Speaker: 光 宮尾

miyao.pdf

17:20 Looking closer at the U(1)_(B-L) explanation of the ATOMKI nuclear anomalies

We revisit the gauged U(1)B−L explanation of the ATOMKI nuclear anomalies, in which the new gauge boson is the hypothetical X(17) particle. It is known that the vanilla B−L scenario is unable to account for appropriate couplings, namely the suppression of the couplings of X(17) to neutrinos, which motivates adding vector-like leptons. The simplest case, in which the new fields have B−L charges equal to 1, is highly disfavoured since it requires large mixing with the Standard Model fields. One solution recently put forward is to consider large B−L charges to counterbalance small mixing. We show that, in this scenario, and after taking into account several phenomenological constraints, the dominant contribution to the muon anomalous magnetic moment (g−2)μ is expected to be extremely large and with a negative sign, being thus excluded by experiment.

Speaker: Bernardo Lopes Gonçalves

Bernardo Goncalves PLANCK2024.pdf

17:40 Extending the SM with vector-like quarks: consequences for CKM unitarity and CP violation

Although, a fourth chiral generation of fermions is excluded by experimental data, the possibility of extending the SM with vector-like quarks, where both chiral components transform the same way under SU(2)_L, has not been ruled out. In fact, these fields are present in a great variety of NP models, from GUTs to solutions to the strong CP problem.
Moreover, introducing VLQs leads to the loss of CKM unitarity making them some of the simplest solutions to the Cabibbo Angle Anomaly (CAA). However, this in turn leads to the emergence of flavour changing neutral currents at tree-level and other phenomenological effects. Additionally, their introduction leads to extended mass matrices with a larger content of physical phases and thus new sources of CP violation, which could have important implications for baryogenisis.
Here we explore the main phenomenological effects of adding VLQs, in particular in the context of addressing the CAA; discuss how one may construct weak basis invariants for the extended theory and present some of the most important CP-odd invariants, which may point to potentially observable CP violation even at collisions with energies much higher than the EW scale.

Speaker: José Bastos

BASTOS.pdf

18:00 Quarks at the modular $S_4$ cusp

We analyse the possibility of describing quark masses, mixing and CP violation in $S'_4$ modular flavour models without flavons. We focus on the case where the closeness of the modulus to the point of residual $\mathbb{Z}^{ST}_3$ symmetry (the cusp) plays a role in generating quark mass hierarchies and discuss the role modular form normalisations play in such constructions. We find that fitting quark data requires explicit CP breaking, unless a second modulus is introduced.

Speaker: Miguel Levy

Planck_Levy_v2.pdf

18:20 Modular stabilisation in the multiple-modulus framework

Modular symmetry provides us with a satisfactory and appealing framework for addressing the flavour problem. The only flavons present in such a framework are one or more moduli fields $\tau$. It seems that the fixed points $\tau = i$ and $\omega$ play a special role in both the phenomenological model building and the 10d supersymmetric orbifold examples. In this talk, I will investigate a modulus stabilisation mechanism in the multiple-modulus framework which is capable of providing de Sitter (dS) global minima precisely at the fixed points $\tau = i$ and $\omega$, by taking into consideration non-perturbative effects on the superpotential and the Kähler potential. Due to the existence of additional Kähler moduli, more possible vacua can occur, and the dS vacua could be in general the deepest. I will classify different choices of the vacua, and discuss their phenomenological implications for lepton masses and flavour mixing.

Speaker: Xin Wang (University of Southampton)

Xin-Planck2024-Modular stabilisation&Inflation.pdf

18:40 Reduction of Couplings in the 2HDM

The method of reduction of couplings consists in the search for relations between seemingly independent couplings that are renormalization group invariant. In this talk the existence of such 1-loop relations among the top Yukawa, the Higgs quartic and the gauge colour couplings of the Type-II Two Higgs Doublet Model at a high-energy boundary is demonstrated. The phenomenological viability of the reduced theory suggests the value of tanβ and the scale in which new physics may appear.

Speaker: Dr Gregory Patellis (Instituto Superior Técnico, CFTP)

Patellis_PLANCK2024.pdf

16:40 → 19:00 Parallel Session PII.7

Convener: Catarina Cosme (U. Coimbra)

16:40 Boosting galactic dark matter with relic supernova neutrinos

Diffuse neutrinos from past supernovae in the Universe present
us with a unique opportunity to test dark matter (DM) interactions.
These neutrinos can scatter and boost the DM particles in the Milky Way
halo to relativistic energies allowing us to detect them in terrestrial
laboratories. In this talk, I will discuss how the consideration of
energy-dependent cross-sections for DM interactions can significantly
affect constraints previously derived under the assumption of constant
cross-sections, modifying them by multiple orders of magnitude. I will
focus on generic models of DM-neutrino and electron interactions,
mediated by a vector or a scalar boson, and discuss new limits obtained
on DM-neutrino and electron interactions for DM with masses in the range
$\sim (0.1, 10^4)$~MeV, using recent data from XENONnT, LUX-ZEPLIN, and
PandaX-4T direct detection experiments.

Speaker: Manibrata Sen

manibrata.pdf

17:00 The interplay between Primordial Black Holes and Leptogenesis

Primordial Black holes (PBHs) with masses lighter than 10^15 grams should have been evaporated by now giving potentially access to the physics of the Early Universe. In particular, the presence of PBHs could have impacted the process of leptogenesis in different ways depending on the mass and so on the temperature of the PBHs. We present the impact of the non-standard cosmology driven by the presence and the evaporation of light primordial black holes on the production of the baryon asymmetry of the Universe in different scenarios of leptogenesis.

Speaker: Marco Chianese (University of Naples Federico II & INFN)

PLANCK24_chianese.pdf

17:20 Regurgitated Dark Matter

We present a new model for WIMP production based on the formation and subsequent evaporation of early Universe primordial black holes (PBHs) themselves formed from DM particles. We consider a first order phase transition that traps the initially thermal DM particles, resulting in the formation of Fermiball remnants that collapse to PBHs, which then emit the same types of DM particles. We show that the regurgitated DM scenario allows for DM to be fermions in the WIMP mass range $\sim 1 \textrm{ GeV}− 10^4 \textrm{ GeV}$ and beyond, thereby unlocking parameter space considered excluded.

Speaker: Philip Lu (KIAS)

Regurgitated Dark Matter Planck.pdf

17:40 Relic \nu Background boosted in Cosmic Reservoirs

Abstract: The relic \nu background (R\nu B) is the `holy grail’ of neutrino physics and it is also the only known Dark Matter subcomponent. Yet, it has so far escaped detection attempts, mainly due to the very low energies and very weak cross-sections involved in the detection channels. In this talk, I will describe the mechanism by which ultra-high energy (UHE) cosmic rays, stored in cosmic reservoirs for \sim Gyr timescales, can upscatter the R\nu B to ultra-high energies. For sufficiently high overdensities of the R$\nu$B in the location of the source, which may potentially be induced by BSM effects, the up-scattered neutrino flux is within the reach of future UHE neutrino detection experiments (e.g. IceCube-Gen2 and GRAND) and distinguishable from other neutrino signals via its unique features such as its spectral shape and flavour composition. The non-detection of this flux at current UHE neutrino experiments sets the current most stringent bound on neutrino overdensities on the scales of galaxy clusters.

Speaker: Andrea Giovanni De Marchi

PLANCK_De_Marchi.pdf

18:00 No talks - Room booked for another event

16:40 → 19:00 Parallel Session PII.8

Convener: Salvador Centelles Chulia (Max-Planck-Institut für Kernphysik)

16:40 Phenomenological implications of neutrinos and axions in Many Species Theories

The framework of TeV scale gravity theories was originally invented to solve the hierarchy problem. One specific BSM model is the Many Species Theory in which the scale of quantum gravity gets lowered by the existence of many additional light states. In this talk, we want to present how small neutrino masses can be generated in this infrared approach and how this modifies the oscillation pattern. Then we present how current neutrino data can be used to give a lower bound on the number of additional species. Moreover, we show how to get an upper bound from axion physics. These results give the first time a theoretically restricted parameter space that can be tested by current and future experiments.

Speaker: Dr Manuel Ettengruber (german)

Planck2024.pdf

17:00 How long do neutrinos live and how much do they weigh?

The observation of neutrino flavor oscillations marks the dawn of a new era in neutrino physics: the era of massive (and decaying) neutrinos. Neutrinos produced by core-collapse Supernova explosions open the possibility to simultaneously study, together with the mechanism driving the stellar explosion, also neutrinos properties, as their mass and lifetime. The next-generation water Cherenkov Hyper-Kamiokande detector will be able to detect thousands of neutrino events from a galactic Supernova explosion via Inverse Beta Decay processes followed by neutron capture on Gadolinium. This superb statistics provides a unique window to set bounds on these neutrino properties via the time delay and the flux suppression induced in the Supernovae neutrino time and energy spectra. Special attention should be devoted to the statistically sub-dominant elastic scattering induced events, which can substantially improve the neutrino mass bound via time delays. When allowing for a invisible decaying scenario, the $95\%~$C.L. lower bound on $\tau/m$ is almost one order of magnitude better than the one found with SN1987A neutrino events. Simultaneous limits can be set on both $m_\nu$ and $\tau_{\nu}$, combining the neutrino flux suppression with the time-delay signature. The tightest $95\%~$C.L. bounds on the neutrino mass found results to be competitive with the tightest neutrino mass limits nowadays, but also comparable to future laboratory direct mass searches.

Speaker: Federica Pompa

PLANCK24_FP.pdf

17:20 The Type-I Seesaw family

Models based on the type-I seesaw mechanism are among the most popular ones for explaining neutrino masses. These models predict that neutrinos are Majorana fermions, either through the explicit or the spontaneous breaking of lepton number. Furthermore, some models introduce seesaw mediators at very high energy scales, while others operate at energies not far from the electroweak scale. I will provide a comprehensive analysis of the Type-I Seesaw family of neutrino mass models, including the conventional type-I seesaw and its low-scale variants. After showing that all these models correspond to a particular form of the type-I seesaw when the breaking of lepton number is explicit, I will delve into the more interesting scenario of spontaneous lepton number violation, systematically categorizing all inequivalent minimal models. In the latter scenario, a Goldstone boson emerges in the spectrum, the majoron ($J$). This leads to a very rich phenomenology and allows for the differentiation among models. In particular, I will discuss models in which, despite having heavy mediators and not being visible in processes such as $\mu \to e \gamma$, could be tested in experiments looking for $\mu \to e J$.

Speaker: Antonio Herrero

TheTypeISeesawFamily.pdf

17:40 Charged Lepton Flavour Violation in the Inverse Seesaw

We discuss Charged Lepton Flavour Violating (CLFV) signals in inverse seesaw scenarios with 3+3 heavy sterile states and flavour and CP symmetries. In this framework the heavy sterile states are (almost) degenerate in mass, while the flavour structure of the neutrino Yukawa coupling is non-trivial. Different lepton mixing patterns are predicted depending on the choice of residual groups preserved among charged leptons and the neutral states. The compatibility of our scenario with bounds of CLFV processes is investigated, and bounds on the parameters (e.g. the masses of heavy sterile states) are derived. The possibility of distinguishing different choices of symmetries through such signals is also studied.

Speaker: Mr Francesco Paolo Di Meglio (IFIC, Valencia)

Planck2024.pdf

18:00 Thermal leptogenesis in the minimal gauged U(1)Lμ-Lτ model

We discuss the thermal leptogenesis mechanism within the minimal gauged U(1)$_{L_\mu-L_\tau}$ model to explain the observed baryon asymmetry of the Universe (BAU). In such framework, the phases of the Pontecorvo–Maki–Nakagawa–Sakata neutrino mixing matrix and the sum of the Standard Model neutrino masses are predictable because of a restricted neutrino mass matrix structure. Additionally, in the context of thermal leptogenesis, the BAU can be computed in terms of the three remaining free variables that parameterise the right-handed neutrino masses and their Yukawa couplings to the Higgs and lepton doublets. We identify the ranges of such parameters for which the correct BAU can be reproduced. We adopt the formalism of the density matrix equations to fully account for flavour effects and consider the decays of all the three right-handed neutrinos. Our analysis reveals that thermal leptogenesis is feasible within a wide parameter space, specifically for Yukawa couplings ranging from approximate unity to $\mathcal{O}(0.03-0.05)$ and mass of the lightest right-handed neutrino $M_1\gtrsim 10^{11-12}\,\text{GeV}$, setting a leptogenesis scale in the considered model which is higher than that of the non-thermal scenario.

Speaker: Juntaro Wada (University of Tokyo)

PLANCK2024_Juntaro_Wada.pdf

18:20 A minimal solution to the axion isocurvature problem from a non-minimal coupling

The main limitation for pre-inflationary breaking of Peccei-Quinn (PQ) symmetry is the upper bound on the Hubble rate during inflation from axion isocurvature fluctuations. This leads to a tension between high scale inflation and QCD axions with Grand Unified Theory (GUT) scale decay constants, which reduces the potential for a detection of tensor modes at next generation CMB experiments. We propose a mechanism that excplicitly breaks PQ symmetry via non-minimal coupling to gravity, that lifts the axion mass above the Hubble scale during inflation and has negligible impact on today's axion potential. The initially heavy axion gets trapped at an intermediate minimum during inflation given by the phase of the non-minimal coupling, before it moves to its true CP-conserving minimum after inflation. During this stage it undergoes coherent oscillations around an adiabatically decreasing minimum, which slightly dilutes the axion energy density, while still being able to explain the observed dark matter relic abundance. This scenario can be tested by the combination of next generation CMB surveys like CMB-S4 and LiteBIRD with haloscopes such as ABRACADABRA or CASPEr-Electric.

Speaker: Maximilian Berbig (IFIC & University of Valencia)

MB-Planck2024-AxionIsocurvature.pdf

18:40 Impact of non-standard interactions on low-scale leptogenesis and neutrinoless double beta decay

In this talk, we investigate the interplay between the observation of lepton number violating processes and the generation of the baryon asymmetry of the Universe via low-scale leptogenesis. We focus on the impact of non-standard interactions, beyond the usual Majorana mass term, on the observation of neutrinoless double beta decay and the resulting parameter space for successful leptogenesis. Parameterizing these effects in a model independent way, we showcase how additional operators can influence the final baryon asymmetry.

Speaker: Sascha Weber (Johannes Gutenberg-Universität Mainz)

weber.pdf

Friday 7 June

09:30 → 10:00 Invariants and Lepton Flavour

TBA

Speaker: Sacha Davidson

DavidsonPlanck.pdf

10:00 → 10:30 CMS Physics

TBA

Speaker: Nuno Leonardo (LIP)

leonardo_cms.pdf

10:30 → 11:00 Coffee Break

11:00 → 11:30 Axion Dark Matter from Kinetic Misalignment

TBA

Speaker: Geraldine Servant

Servant-Lisbon-axions-2024.pdf

11:30 → 12:00 Dark Dimension, Swampland, and Effective Field Theory Limit

TBA

Speaker: Vincenzo Branchina (Universita e INFN (IT))

4Branchina-Planck-2024.pdf

12:00 → 12:30 Stability of multibrane worlds

TBA

Speaker: Marek Olechowski

Olechowski.pdf

12:30 → 14:30 Lunch Break

14:30 → 15:00 Finite modular symmetries and the strong CP problem

Speaker: Dr Joao Penedo

Penedo_PLANCK24.pdf

15:00 → 15:30 Flavor's Delight

TBA

Speaker: Hans Peter Nilles (Technische Universitaet Muenchen (DE))

NillesPlanck24.pdf

Planck2025-Padua.pdf

15:30 → 15:40 Closing of the Conference

Closing of the Conference

15:40 → 16:10 Coffee Break