Saturnalia 2022

16 Dec 2022, 09:00 → 22 Dec 2022, 19:30 Europe/Madrid

Seminario de Física Atómica y Nuclear y ONLINE https://rediris.zoom.us/j/7818936953 (Facultad de Ciencias and ONLINE https://rediris.zoom.us/j/83767424733)

Javier Redondo, Jorge Alda, Mathieu Kaltschmidt, Siannah Peñaranda

Conference series dedicated to catch up with the recent Theoretical and Experimental developments in the broad range of fields covered by our newborn center CAPA,  as well as with the adventures and misfortunes of our dear young expats.

This year we will have a mixed format, in-person meetings with zoom broadcast

saturnalia22_poster.pdf

Friday 16 December

Afternoon session

Zoom link: https://rediris.zoom.us/j/83767424733

1 Searching for Dark Photons with IAXO

Axion heliioscopes such as CAST have been used to search for dark photons and, in the absence of their detection, set a limit on dark photon parameters. I am using similar analysis to determine the parameter space that IAXO will be able to explore, and will extend this analysis to include the mixing of different polarisations of solar plasmons by the sun's magnetic field and how this mixing can affect the dark photon flux

Speaker: Tomás Gerard O Shea (CAPA)

Monday 19 December

Morning session

Zoom link: https://rediris.zoom.us/j/83767424733

2 Using X-ray optics for nuclear physics applications

Speaker: Jaime Ruz (CAPA)

3 ALP production in weak mesonic decays

Axion-Like-Particles are among the most economical and well motivated extensions of the Standard Model. In this talk ALP production from hadronic and leptonic meson decays are studied. The hadronization part of these decay amplitudes has been obtained using Brodsky-Lepage method or LQCD, at needs. In particular, the general expressions for ALP emission in mesonic s- and t-channel tree-level processes are thoroughly discussed, for pseudoscalar and vector mesons. Accordingly, results and useful approximation for meson-to-meson and meson leptonic decay amplitudes are presented.
I will the discuss the phenomenology of various decays and highlight the most robust in terms of experimental searches and theoretical predictions. Finally, bounds on the (low-energy effective Lagrangian) ALP--fermion couplings are derived, from present and future flavour experiments. If I have time left I'll also cover some of the new form factors calculations in B mesogenesis.

Speaker: Alfredo Walter Mario Guerrera (Università degli Studi di Padova/INFN)

Saturnalia22_Guerrera.pdf

Tuesday 20 December

Morning session

Zoom link: https://rediris.zoom.us/j/83767424733

4 Searching for ALPs-photon conversion on fiber interferometer

Speaker: Yikun Gu (Hamburg University)

5 Parametric resonances in domain walls and cosmic strings

Based on
https://arxiv.org/abs/2209.12945
https://arxiv.org/abs/2212.06194

Speaker: Daniel Jiménez Aguilar (UPV/EHU)

Zaragoza_slides_DanielJimenezAguilar.pdf

Afternoon session

Zoom link: https://rediris.zoom.us/j/83767424733

6 Cosmology from SKA Observatory pathfinders

Speaker: Jacobo Asorey (Universidad Complutense de Madrid)

Saturnalia_Jacobo_Asorey_2022 copia.pdf

7 Formation of shadows around compact objects as observational proofs of new gravitational physics

In this talk I will discuss the features of the formation of shadows around some (ultra)-compact objects due to the presence of light rings surrounding the central depression of optically-thin accretion disks. The shapes of the shadows might reveal novel spacetime structures beyond the well known Kerr family, such that future observations of additional light rings through very-long baseline interferometry will make a compelling case for the existence of new gravitational physics.

Speaker: Diego Sáez

Saez_Saturnalia2022.pdf

Wednesday 21 December

Morning session

Zoom link: https://rediris.zoom.us/j/83767424733

8 Machine-learned exclusion limits without binning

Machine-Learned Likelihood (MLL) is a method that, by combining modern machine-learning classification techniques with likelihood-based inference tests, allows to estimate the experimental sensitivity of high-dimensional data sets. We extend the MLL method by including the exclusion hypothesis tests, and show that the addition of Kernel Density Estimators avoids the need to bin the classifier output in order to extract the resulting one-dimensional signal and background probability density functions. We first test our method on a toy model of multivariate Gaussian distributions, where the true probability distribution functions are known. We then apply it to a case of interest in the search for new physics at the LHC, in which a Z' boson decays into lepton pairs, comparing the performance of MLL for estimating 95% CL exclusion limits to the prospects reported by ATLAS at 14 TeV with a luminosity of 3 ab^{-1}.

Speaker: Rosa María Sandá Seoane (IFT Universidad Autónoma de Madrid-CSIC)

Charla_Saturnalia_2022_RMSanda.pdf

9 Using Machine Learning techniques in phenomenological studies in flavour physics

In the recent years, a series of measurements in the observables RK(*) and RD(*) concerning the semileptonic decays of the B mesons have shown hints of violations of Lepton Flavour Universality (LFU). An updated model-independent analysis of New Physics violating LFU, by using the Standard Model Effective Field Theory (SMEFT) Lagrangian with semileptonic dimension six operators at Λ = 1 TeV is presented. We perform a global fit, in order to assess the impact of the New Physics in a broad range of observables including B-physics, electroweak precision test, Higgs physics and nuclear β decays. We discuss the relevance of the mixing in the first generation for the observables with heavier lepton flavours. We use for the first time in this context a Montecarlo analysis of the likelihood function to extract the confidence intervals and correlations between observables. Our results show that a suitable strategy is to use a Gradient Boosting predictor as a proxy of the real likelihood function, and to analyze the SHAP values as a measure of the impact of each parameter of SMEFT Lagrangian in the fit.

Speaker: Jorge Alda (CAPA)

slides.pdf

Afternoon session

Zoom link: https://rediris.zoom.us/j/83767424733

10 Automatic Nelson-Barr from Gauged Flavor and ALP searches at FASER

Despite the exceptional appeal of the Peccei-Quinn mechanism as a solution to the strong CP problem, alternative mechanisms should still be pursued. In this direction, I will present in the first part of my talk how a Nelson-Barr mechanism (NB) arises automatically in the context of gauged flavor models. Given the tight connection of the strong CP problem with flavor, this framework will be shown to solve some of the issues of usual NB realizations.
In the second part of my talk, I will briefly comment on a recent idea to look for axions using the LHC as a Light Shining through Wall experiment. Based on 2204.03599.

Speaker: Pablo Quílez (DESY)

Saturnalia 2023- Automatic NB from gauged flavor.pdf

Thursday 22 December

Morning session

Zoom link: https://rediris.zoom.us/j/83767424733

11 Over the Rainbow ... of Gravitational Waves

Gravitational waves from different frequencies bring information about different phenomena of the Universe. CMB studies, Ligo-Virgo-Kagra, PTA and LISA-like missions are able to provide relevant information in several bands, but leave some gaps where new signals may be hiding. In this talk, I’ll first give an overview of the different phenomena probed and main detection strategies at different frequencies After that, I‘ll focus on two gaps poorly studied by these searches (the microHz band and gravitational waves above kHz) and describe why they are important and some ideas to reach interesting sensitivities.

Speaker: Diego Blas (UAB/IFAE)

Blas_Saturnalia2022.pdf

12 Doubly special relativity as a road to quantum gravity

Speaker: Javier Relancio Martínez (Universidad de Burgos)

Saturnalia_22_Relancio.pdf