# 23rd International Conference From the Planck scale to the Electroweak scale (Planck 2021)

Europe/London
Description

The Planck conference series covers a broad spectrum of physics beyond the Standard Model and of the interface between particle physics and cosmology with an emphasis on the theoretical aspects related to the present experimental programmes.

The conference this year is the twenty-third in a series of meetings on Physics beyond the Standard Model, organized jointly by several European research groups.

The meeting this year in 2021 has a different format for obvious reasons, and will be held online by the IPPP. As well as a slimmed down set of plenary talks we will be providing opportunities for remote interaction using Gather.town so that we can all get a chance to meet new colleagues and old friends as usual. We look forward to welcoming you even if only virtually!

Confirmed speakers

 Prateek Agrawal Lara Anderson Daniel Baumann Monika Blanke Ilaria Brivio Danny van Dyk Marco Drewes Miguel Escudero Malcolm  Fairbairn Roberto Franceschini            Isabel Garcia Garcia Yonit Hochberg Joachim Kopp Thomas Kuhr Rebecca Leane Michelangelo Mangano Mitesh Patel Marianna Safronova Adam Schreckenberger Ofri Telem Irene Valenzuela

Local Organizers

 Steven Abel Djuna Croon            Rick Gupta Lucien Heurtier Rachel Houtz Michael Spannowsky
Participants
• Abbey Kitson
• Abhishek Roy
• Afif Omar
• Ahmed Ali
• Alejo Nahuel Rossia
• Aleks Smolkovic
• Alexis Plascencia
• Alon Faraggi
• Alvaro Herraez
• AMAN Gupta
• Anders Eller Thomsen
• Andreas Weiler
• Anirudh Prabhu
• Anish Ghoshal
• Anisha .
• Anke Biekoetter
• Anubhav Mahapatra
• Aoife Bharucha
• Aqil Khan
• Arthur Platschorre
• Benjamin Allanach
• Benjamin Berczi
• Bernardo Gonçalves
• Bethany Suter
• Bikash Thapa
• Binesh Mohan
• Biswajit Karmakar
• Björn Herrmann
• Bowen Fu
• Brian Shuve
• Catarina Cosme
• Chao Chen
• Chen SUN
• Chengcheng Han
• Christas Mony A
• Christophe Grojean
• CHRISTOS KOKORELIS
• Ciara Byers
• Daniel Lewis
• David Schaich
• David Stefanyszyn
• Debajit Bose
• Debtosh Chowdhury
• Deheng Song
• Dipan Sengupta
• Débora Barreiros
• Eduardo Gonzalo
• Edward Wang
• Eleanor Jones
• Elena Pinetti
• Elias Kiritsis
• Elina Fuchs
• Emilian Dudas
• Enrico Morgante
• Erwin Tanin
• Eun-Kyung Park
• Fa Peng Huang
• Fajfer Svjetlana
• Fazlollah Hajkarim
• FEI HUANG
• Flip Tanedo
• Florian Nortier
• Francesco Serra
• Francisco Campos Oliden
• Ganesh Subramaniam
• Georg Weiglein
• George Leontaris
• Gian Luigi Alberghi
• Giorgio Busoni
• Giovanni Grilli di Cortona
• Gonzalo Herrera
• Grégory Moreau
• Hanieh Karimi
• Hans Peter Nilles
• Hector Gisbert Mullor
• Henrique Brito Câmara
• Hironori Hoshino
• Iason Baldes
• Iason Baldes
• Ilaria Brivio
• Imanol Corredoira
• Isabel Garcia Garcia
• Jacob Leedom
• Jacob Linacre
• Jan Tristram Acuña
• Jarek Nowak
• Jasper Roosmale Nepveu
• Jeff Kost
• Jessica Turner
• Jiaming Shi
• Jiayin Gu
• Jim Talbert
• Jingjing Yang
• Jinsu Kim
• Joachim Kopp
• John March-Russell
• Jonas Rezacek
• Joy Ganguly
• Juan Rojo
• Junsei Tokuda
• Jure Zupan
• Keisuke Harigaya
• Kelan Treanor
• Kensuke Akita
• Kim Berghaus
• Koichi Hirano
• Konstantinos Dimopoulos
• Lara Anderson
• Leonard Romano
• Ling-Xiao Xu
• Lotfi Boubekeur
• Louis Lyons
• Luca Armando Nutricati
• Luciano Petruzziello
• Lukas Witkowski
• Malcolm Fairbairn
• Mar Ciscar
• Marco Costa
• Marco Drewes
• Marianna Safronova
• Mariano Quiros
• Mario Reig
• Martin Bauer
• Masar Abdulzahra Al-muttairi
• Mathias Pierre
• Matthew Kirk
• Matthias Schlaffer
• Maud SARAZIN
• Maíra Dutra
• Merlin Reichard
• Michael Nee
• Michael Schmidt
• michelangelo mangano
• Michele Frigerio
• Michele Tammaro
• Miguel Escudero
• Mikael Chala
• Mitesh Patel
• Mitsuru Kakizaki
• Monika Blanke
• Murat Abdughani
• Nakorn Thongyoi
• Nashwan Sabti
• Navin McGinnis
• Neil Barrie
• Neil Barrie
• Nicole Righi
• Ofri Telem
• Pablo Martínez-Miravé
• Pham Ngoc Hoa Vuong
• Philipp Klose
• Prateek Agrawal
• Pyungwon Ko
• Quentin Bonnefoy
• Rachel Houtz
• Rakhi Mahbubani
• Ralph Torres
• Ramani Lachyan
• Ranjini Mondol
• Rebecca Leane
• Rhea Moutafis
• RINKU MAJI
• Roberto Franceschini
• Rohan Pramanick
• Roy Lemmon
• Rupert Coy
• Saarik Kalia
• Saboura Zamani
• Sacha Davidson
• Saeed Ur Rahman
• Saeid Foroughi-Abari
• Sagarika Rao Valluri
• Salvatore Bottaro
• Samuel Sanchez Lopez
• Samuel Wong
• Sebastian Baum
• Sebastian Ellis
• Sebastian Schenk
• Serah Moldovsky
• shigeo ohkubo
• Shinta Kasuya
• Shohei Okawa
• Shoichi Ichinose
• Shuntaro Aoki
• Simon Riquelme
• Sina Etebar
• Sonali Verma
• Sovan Sau
• Stefan Pokorski
• Steve King
• Steven Abel
• Stéphane Lavignac
• Suddhasattwa Brahma
• Supratim Das Bakshi
• Suruj Jyoti Das
• Susanne Westhoff
• Tanner Trickle
• Terrance Figy
• Thejus Mary S.
• Thomas Colas
• Thomas Kuhr
• Tim Jones
• Tirtha Sankar Ray
• Tobias Hurth
• Valery Khoze
• Vasileios Basiouris
• Veronica Guidetti
• Vincenzo Branchina
• Vivek Pathak
• Viviana Niro
• Volodymyr Aushev
• William DeRocco
• Xabier Marcano
• Xianguo Lu
• Xiu-Fei Li
• Yann Mambrini
• Yannis Georis
• Yi Zhang
• Yifan Chen
• Yong Xu
• Yosef Nir
• Yves Sirois
• Zahra Tabrizi
• Monday, June 28
• Opening Remarks
Convener: Steven Abel (IPPP)
• Dark Universe / Astro-particles
• 1
Dark Matter Hunting in 2021 – How do you look for something when you don’t know what it is?

The Search for clues as to the nature of Dark Matter continues in more varied and novel ways than ever before and has never been more challenging nor more stimulating. In this talk I will describe a variety of approaches that have been worked on over the past years, focusing shamelessly on those I have been involved in personally. We can learn about dark matter through observations of dwarf galaxies, by trying to explain anomalies at particle physics experiments (both collider and direct detection experiments), and also by looking at the impact of the dark sector on relics left over from the big bang in the form of nuclei and gravitational waves. I will also discuss some of the other physics which may emerge along the way and briefly comment on what we can expect from the future.

Speaker: Malcolm Fairbairn (King's College London)
• 2
The quest for the origin of matter

Observations strongly indicate that the baryonic matter in the observable universe is the remnant of a matter-antimatter asymmetry in the primordial plasma, which cannot be explained by the Standard Model of particle physics. If the new particles that are responsible for this asymmetry have masses below the TeV scale they may be discovered within the next decade. Using the example of low scale leptogenesis, we demonstrate that observables from different experiments can be combined to test the hypothesis that these particles are indeed the origin of matter. A key ingredient are state-of-the art simulations of processes in the early universe to make predictions for the properties of the new particles based on the requirement to explain the observed baryon-to-photon ratio.

Speaker: Marco Drewes
• Beyond the Standard Model
• 3
Axion Strings in the Sky

I will present some remarkable signals of axion strings coupled to photons. There are compelling theoretical motivations to expect axion strings that persist in the sky today. There is a model-independent polarization rotation of CMB photons in the string background, equal to $\alpha_{em}$ up to a rational number related to the fundamental unit of electromagnetic charge. This manifests itself as a rotation of E-modes in the CMB polarization to B-modes. The current CMB experimental sensitivity to this rotation is about 1%, with many orders of magnitude improvement expected for future experiments. As these strings pass through galactic magnetic fields, they build up localized charge and current density traveling along the string. This sets up a cosmological plasma collider where collisions can occur at very high energies and produce spectacular astrophysical signals.

Speaker: Prateek Agrawal
• 2:30 PM
Coffee break: Come share a coffee break with us on gather.town! (Link communicated by email)

Come share a coffee break with us on gather.town! (Link communicated by email)

• Dark Universe / Astro-particles
• 4
Detecting Dark Matter in Celestial Bodies

Stars and planets can be ideal playgrounds to discover dark matter. In this talk, I will review a range of dark matter searches using celestial objects, including neutron stars, exoplanets, solar-system planets, and our Sun. I will discuss different search strategies, their opportunities and limitations, and the interplay of regimes where different celestial objects are optimal detectors.

Speaker: Rebecca Leane
• Beyond the Standard Model
• 5
Bounce of Nothing
Speaker: Isabel Garcia Garcia
• 6
Amplitudes for Monopoles

On-shell methods are particularly suited for exploring the scattering of electrically and magnetically charged objects, for which there is no local and Lorentz invariant Lagrangian description. In this paper we show how to construct a Lorentz-invariant S-matrix for the scattering of electrically and magnetically charged particles. A key ingredient is a revision of our fundamental understanding of multi-particle representations of the Poincaré group. Surprisingly, the asymptotic states for electric-magnetic scattering transform with an additional little group phase, associated with pairs of electrically and magnetically charged particles. The corresponding “pairwise helicity” is identified with the quantized “cross product” of charges, e1g2 − e2g1, for every charge-monopole pair, and represents the extra angular momentum stored in the asymptotic electromagnetic field. We define a new kind of pairwise spinor-helicity variable, which serves as an additional building block for electric-magnetic scattering amplitudes. We then construct the most general 3-point S-matrix elements, as well as the full partial wave decomposition for the 2 → 2 fermion-monopole S-matrix. In particular, we derive the famous helicity flip in the lowest partial wave as a simple consequence of a generalized spin-helicity selection rule, as well as the full angular dependence for the higher partial waves. Our construction provides a significant new achievement for the on-shell program, succeeding where the Lagrangian description has so far failed.

Speaker: Ofri Telem
• Tuesday, June 29
• Flavour phenomenology
• 7
B-Mesogenesis: Baryogenesis and Dark Matter from B Mesons

I will present a new mechanism for Baryogenesis and Dark Matter production: B-Mesogenesis. Within the B-Mesogenesis paradigm, both the dark matter relic abundance and the baryon asymmetry of the Universe arise from the CP violating oscillations of B mesons and their subsequent decays in the early Universe. This mechanism would have distinctive experimental signals that I will discuss in detail: i) the new decay mode of B mesons into a baryon and missing energy and ii) a positive semileptonic asymmetry in neutral B meson decays. I will discuss the reach of current collider experiments to these signatures, and I will show that a combination of measurements at Belle II, LHCb, ATLAS & CMS can fully test B-Mesogenesis.

Speaker: Miguel Escudero
• 8
Flavour Anomalies: Hints for BSM physics in expected and unexpected places

Quark flavour physics has received a lot of attention over the last decade. The influx of attention is driven by the so-called flavour anomalies: a series of statistically significant tensions between Standard Model predictions and measurements, shy of the celeberated 5 sigma significance. I will review the status of the so-called "b anomalies", a subset of the flavour anomalies, and provide context for the theoretical information required for their interpretation.

Speaker: Danny van Dyk (TU München)
• 9
Neutrinos as a Window to New Physics

We discuss some of the manifold ways in which neutrino experiments can be leveraged to probe physics beyond the Standard Model. Topics covered will include searches for light dark sectors, constraints on Standard Model Effective Field Theory (SMEFT) using LHC neutrinos, and neutrino magnetic moments. In the latter case, we highlight interesting connections to the muon g-2 anomaly and to some of the quark flavor anomalies.

Speaker: Joachim Kopp
• 2:30 PM
Coffee Break: Come share a coffee break with us on gather.town! (Link communicated by email)

Come share a coffee break with us on gather.town! (Link communicated by email)

• Higgs phenomenology
• 10
The SMEFT program at the LHC

The LHC experiments are entering a precision era, where the sensitivity to indirect effects of new physics, i.e. discrepancies between data and SM predictions, will increase substantially.
Searches for these signals are most conveniently performed within the framework of the Standard Model Effective Field Theory (SMEFT), that allows to implement a very ambitious program: a systematic search for inconsistencies with SM predictions in a large number of different processes, from which "agnostic" information about new physics can be extracted via a combined SMEFT interpretation.
I will review the current status of this effort, that has seen important theoretical and experimental advancements in recent years. I will focus in particular on studies in the Higgs sector and on the complementarities between Higgs, electroweak and top quark processes.

Speaker: Ilaria Brivio
• 11
Prospects for Higgs measurements at future colliders

I review the potential of future colliders to improve the knowledge of Higgs properties, emphasizing the synergy and complementarity between lepton and hadron facilities.

Speaker: Michelangelo Mangano (CERN)
• 12
Higgs Physics at Future(^2) Colliders

I will discuss where do we stand in the task of characterizing the Higgs boson at LHC, the future prospects to learn more from the HL-LHC and future colliders presently under study. I will focus in particular on the long term goals in the exploration of Higgs boson properties and and possible lessons to be learned about electroweak symmetry breaking.

Speaker: Roberto Franceschini (Rome 3 University)
• Wednesday, June 30
• String Phenomenology
• 13
Bootstrapping Cosmological Correlations

Cosmology is famously an observational rather than an experimental science. No experimentalists were present in the early universe, and the birth and subsequent evolution of the universe cannot be repeated. Instead, we can only measure the spatial correlations between cosmological structures at late times. A central challenge of modern cosmology is to construct a consistent "history" of the universe that explains these correlations. In the last few years, a new bootstrap approach was developed to understand this history using physical consistency conditions alone. In this talk, I will describe the basic idea behind this "cosmological bootstrap" and explain why it promises new insights into the physics of the very early universe.

Speaker: Daniel Baumann
• 14
SU(3)-Holonomy and SU(3)-Structure metrics from Machine Learning

The metric on the compact internal geometry of a string compacitification has long stood as an important missing piece in the study of low energy physics arising from string theory. I will review recent progress using machine learning to approximate Calabi-Yau and SU(3)-structure metrics, including for the first time their dependence. These methods are demonstrated for Calabi-Yau as well as SU(3)-structure manifolds.

Speaker: Lara B. Anderson
• 15
Light Fermions and the Swampland

Quantum gravity can have important implications for Particle Physics and Cosmology. In this talk, I will describe the state-of-the-art and phenomenological implications of the AdS Distance conjecture and the Non-susy AdS Instability conjecture. In particular, we consider constraints on D-dimensional theories in Minkowski, dS and AdS backgrounds in the light of these swampland conjectures as applied to their compacti cation in a circle. For Minkowski and dS vacua the results may be summarized by a light fermion conjecture which states that in theories with a positive first non-vanishing supertrace $(-1)^{k+1}Str(M^{2k}) > 0$, a surplus of light fermions with mass $m_f < \Lambda_D^{1/D}$ must be present, where $\Lambda_D$ is the cosmological constant. The case of AdS can be made consistent with the mild but not the strong version of the AdS Distance conjecture. I will also apply the above constraints to the Standard Model of particle physics, obtaining that it would be inconsistent in Minkowski space but consistent in dS if the lightest neutrino is Dirac and lighter than the cosmological constant scale, unless there is light fermionic dark matter. This can be translated to an upper bound on the EW scale which may shed some light into the naturalness issues observed in our universe.

Speaker: Irene Valenzuela
• 2:30 PM
Coffee Break: Come share a coffee break with us on gather.town! (Link communicated by email)

Coffee Break: Come share a coffee break with us on gather.town! (Link communicated by email)

• Quantum algorithms and technologies
• 16
New Technologies for Dark Matter Detection

The exploration of dark matter beyond the WIMP is of vital importance towards resolving the identity of dark matter. I will discuss new proposals for the direct detection of light dark matter which hold much promise. These include the use of superconducting nanowires, two-dimensional targets such as graphene, and heavy fermion materials. Considering dark matter interactions with these targets, I will demonstrate the potential of the light dark matter direct detection program in upcoming years.

Speaker: Yonit Hochberg
• 17
Quantum Technologies for New-physics Searches

The extraordinary advances in quantum control of matter and light have been transformative for precision measurements enabling probes of the most basic laws of Nature to gain a fundamental understanding of the physical Universe. Exceptional versatility, inventiveness, and rapid development of precision experiments supported by continuous technological advances and improved atomic and molecular theory led to rapid development of many avenues to explore new physics. I will give an overview of atomic and molecular physics searches for physics beyond the standard model and then focus on dark matter searches with atomic and nuclear clocks.

Speaker: Marianna Safronova
• 4:40 PM
Coffee Break: Come share a coffee break with us on gather.town! (Link communicated by email)

Come share a coffee break with us on gather.town! (Link communicated by email)

• Muon Anomalies
• 18
The B anomalies

An overview of the anomalies observed in measurements of neutral- and charged-current b quark transitions will be presented. Experimental and theoretical challenges for the relevant measurements will be discussed, and at outlook for future developments that may give clarity presented.

Speaker: Mitesh Patel (LHCb) (Imperial College London)
• 19
Belle II: status and prospects

The Belle II experiment at the SuperKEKB energy-asymmetric e+e− collider is a substantial upgrade of the B factory facility at the Japanese KEK laboratory. The target luminosity of the machine is $6\times10^{35}$ cm$^{−2}$s$^{−1}$ and the Belle II experiment aims to record 50 ab$^{−1}$ of data, a factor of 50 more than its predecessor. With this data set, Belle II will be able to measure the Cabibbo-Kobayashi-Maskawa (CKM) matrix, the matrix elements and their phases, with unprecedented precision and explore the B anomalies. Belle II has also a unique capability to search for low mass dark matter and low mass mediators. In this presentation, we will review the status of the Belle II detector, the results of the planned measurements with the full available Belle II data set, and the prospects for physics at Belle II.

Speaker: Dr Thomas Kuhr (Belle II)
• 20
Fermilab Muon g-2: from a_\mu to g

The Fermilab Muon g-2 Collaboration recently measured the muon magnetic anomaly with an unprecedented precision of 0.46 ppm. The new result is consistent with the measurement published by the g-2 experiment based at Brookhaven National Laboratory, and a difference of 4.2 standard deviations exists between the Standard Model prediction recommended by the Muon g-2 Theory Initiative and the combined Fermilab and Brookhaven measurements. This talk will describe the Fermilab experiment and the latest measurement of the muon magnetic anomaly.

Speaker: Dr Adam Schreckenberger (Fermilab g-2 collaboration)
• 21
Theory perspective on the flavour anomalies

Over the past few years, several anomalies related to the violation of lepton flavour universality emerged in charged and neutral current B meson decays, and also the longstanding tension in the muon g-2 has been strengthened by recent data. In this talk I will review possible New Physics explanations of these anomalies and discuss how they can be probed by complementary observables in the flavour sector and beyond.

Speaker: Dr Monika Blanke
• Concluding Remarks
Convener: Michael Spannowsky (IPPP, Durham University)