GGI Tea Breaks' Seminars Report of Contributions

GGI Tea Breaks’ Seminars

Report of Contributions

https://agenda.infn.it/e/26354 GGI Tea Breaks’ … / Report of Contributions Theory Colloquium ”Portals to the…

Contribution ID: 1 Type: not specified

Theory Colloquium ”Portals to the Dark Sector” Wednesday, 24 March 2021 17:00 (1h 30m)

A handful of open questions, such as the nature of the cosmic dark matter, compel the search for a new paradigm of matter and forces. A novel, yet plausible, element of this framework maybea hidden or dark sector of new elementary particles, which does not experience the familiar strong and electroweak interactions. Such a hidden world may still influence our visible world if there is a very weak interaction, or portal, between the two sectors. I will introduce the basic theoretical framework of dark sectors and portals and highlight the growing experimental program to search for a variety of novel phenomena associated with these theories.

Presenter: BATELL, Brian (University of Pittsburgh)

September 26, 2021 Page 1 GGI Tea Breaks’ … / Report of Contributions Theory Colloquium ”How to test q…

Contribution ID: 2 Type: not specified

Theory Colloquium ”How to test quantum theory with thought experiments” Wednesday, 14 April 2021 17:00 (1h 30m)

Quantum theory is one of our most accurate theories ever when it comes to the description of small systems. It is therefore often assumed that the theory can equally well be applied to large objects, sometimes even astronomical ones like black holes. In my talk I will present a thought experiment that indicates that the range of validity of (current) quantum theory may be limited to small systems. (The talk is based on work with Daniela Frauchiger and Nuriya Nurgalieva.)

Presenter: RENNER, Renato (ETH Zurich)

September 26, 2021 Page 2 GGI Tea Breaks’ … / Report of Contributions Theory Colloquium ”Muon g-2: th…

Contribution ID: 3 Type: not specified

Theory Colloquium ”Muon g-2: the showdown” Wednesday, 21 April 2021 17:00 (1h 30m)

The Muon g-2 experiment at Fermilab has recently confirmed Brookhaven’s earlier measurement of the muon anomalous magnetic moment aμ. This new result increases the discrepancy Δaμ with the Standard Model (SM) prediction and strengthens its “new physics” interpretation as well as the quest for its underlying origin. In this talk I will review the SM prediction of the muon g-2, focusing on some of the latest developments, and discuss the connection of the discrepancy Δaμ to precision electroweak predictions via their common dependence on hadronic vacuum polarization effects.

Presenter: PASSERA, Massimo (INFN Padova)

September 26, 2021 Page 3 GGI Tea Breaks’ … / Report of Contributions Theory Colloquium ”Galactic Arch …

Contribution ID: 4 Type: not specified

Theory Colloquium ”Galactic Archaeology and the Search for Dark Matter” Wednesday, 28 April 2021 18:00 (1h 30m)

The Gaia mission is in the process of mapping nearly 1% of the Milky Way’s stars, nearly abillion in total. This data set is unprecedented and provides a unique view into the formation historyof our Galaxy and its associated dark matter halo. I will review recent results demonstrating howthe evolution of the Galaxy can be deciphered from the stellar remnants of massive satellite galaxies that merged with the Milky Way early on. This analysis is an inherently “big data” problem, and I will discuss how to leverage machine learning techniques to advance our understanding of the Galaxy’s evolution. Our results indicate that the local dark matter is not in equilibrium, as typically assumed, and instead exhibits distinctive dynamics tied to the disruption of satellite galaxies. The updated dark matter map built from the Gaia data has ramifications for direct detection experiments, which search for the interactions of these particles in terrestrial targets.

Presenter: LISANTI, Mariangela (Princeton)

September 26, 2021 Page 4 GGI Tea Breaks’ … / Report of Contributions Theory Colloquium ”Flavor Physic …

Contribution ID: 5 Type: not specified

Theory Colloquium ”Flavor Physics: Status and Prospects” Wednesday, 5 May 2021 17:00 (1h 30m)

Measurements of rare flavor changing transitions with either quarks or leptons can beusedto search for signs of new physics. I will review the status of the field, including the recent anomalies in B physics and anomalous magnetic moment of the muon. I will try to give sense of where the field is going next, driven in a large extent with several ambitious experimental programs coming on line in the near to midterm future (the LHCb upgrade, Belle II, Mu2e, MEG-II, etc).

Presenter: ZUPAN, Jure (U. of Cincinnati)

September 26, 2021 Page 5 GGI Tea Breaks’ … / Report of Contributions Focus Meeting ”Naturalness and t …

Contribution ID: 6 Type: not specified

Focus Meeting ”Naturalness and the future of High Energy Physics” Wednesday, 19 May 2021 17:00 (1h 30m)

Naturalness arguments have been a powerful guiding principle for physicists as they try to con- struct new theories. While considerations based on simplicity and elegance have characterized the scientific thought since very early times, numerical naturalness, as most clearly formulated by’t Hooft and Wilson, has been especially influential in the search for theories of fundamental interactions. When applied to our current description of the microscopic world in terms of quantum field theory, it leads to the apparent paradox of the smallness of the electroweak scale and of the cosmological constant as compared to the Planck scale. In this Focus Meeting, Gian Francesco Giudice and Riccardo Rattazzi will review the concept of naturalness and its implications. The seemingly convincing notions of naturalness and simplicity in Effective Field Theory will be introduced and argued that they appear mutually contradictory in both the SM and its natural extensions. This state of things defines the Hierarchy Paradox. The hypotheses on which the naturalness principle rests, the consequences of relaxing some of these hypotheses, and the current attempts to develop new paradigms beyond naturalness will then be discussed.

Presenters: GIUDICE, Gian (CERN); RATTAZZI, Riccardo (EPFL)

September 26, 2021 Page 6 GGI Tea Breaks’ … / Report of Contributions Focus Meeting ”The Precision Leg …

Contribution ID: 7 Type: not specified

Focus Meeting ”The Precision Legacy of the (HL-)LHC” Wednesday, 9 June 2021 17:00 (1h 30m)

The data collected at the LHC and its High-Luminosity successor over the next 20 years willenable a multitude of precise experimental measurements in the Electroweak, Higgs and Top sectors, potentially leading to a systematic program of exploration at the frontier of fundamental physics. The design of this program and its exploitation requires multiple forms of theoretical input, ranging from the definition of the target measurements and their implications on putative newphysics scenarios to the development of sufficiently accurate and easily available theoretical predictions as well as of novel analysis data techniques that will be needed to deal with the amazing richness and complexity of the LHC data. In this Focus Meeting, Fabio Maltoni and Andrea Wulzer will review the current status of the field and give a perspective on the future challenges.

Presenters: WULZER, Andrea (CERN & EPFL, Padova U.); MALTONI, Fabio (Bologna U.)

September 26, 2021 Page 7 GGI Tea Breaks’ … / Report of Contributions Theory Colloquium ”Artificial Inte …

Contribution ID: 8 Type: not specified

Theory Colloquium ”Artificial Intelligence and Fundamental Interactions” Wednesday, 30 June 2021 17:00 (1h 30m)

In this talk, I explain how various concepts and techniques in quantum field theory and collider physics can be naturally translated into a new geometric language. Using the energy mover’s distance, which quantifies the minimal amount of “work” required to rearrange one event into another, we can define a distance between pairs of collider events. This distance can thenbeused to triangulate the “space” of collider events and rigorously define various geometric objects. Many well-known collider observables, jet algorithms, and pileup mitigation schemes have a simple geometric interpretation, as does the important concept of infrared and collinear safety. Intriguingly, these ideas can be lifted from a distance between events into a distance between theories, with potential relevance for visualizing and interpreting data from the LHC.

Presenter: THALER, Jesse (MIT)

September 26, 2021 Page 8 GGI Tea Breaks’ … / Report of Contributions Theory Colloquium ”What are T-…

Contribution ID: 10 Type: not specified

Theory Colloquium ”What are T-Tbar deformations?” Wednesday, 20 January 2021 17:00 (1h 30m)

The presence of an irrelevant field in a quantum field theory is usually not good news, asfar understanding the high-energy physics of the model is concerned. In two space-time dimensions, the T-Tbar deformation is solvable. We can describe physical observables of interest, such as the S- matrix and the finite-volume spectrum, in terms of the corresponding undeformed quantities. For this irrelevant perturbation, we can reverse the renormalization group trajectory and gain exact information about ultraviolet physics. The outcome is stunning: low-energy physics resembles that of a conventional local quantum field theory while at high-energy the density of states ona cylinder shows Hagedorn growth similar to that of a string theory.

Presenter: TATEO, Roberto (TO)

September 26, 2021 Page 9 GGI Tea Breaks’ … / Report of Contributions Theory Colloquium ”Is the ΛCDM …

Contribution ID: 11 Type: not specified

Theory Colloquium ”Is the ΛCDM model in trouble?” Wednesday, 13 January 2021 17:00 (1h 30m)

We’ve known since the late 1920s that the Universe is expanding. However, the expansion rate currently inferred from measurements of the cosmic microwave background now disagrees with that obtained from supernova measurements. Over the past few years, theorists have been explor- ing the possibility that this Hubble tension is explained by some new “early dark energy”: a new component of matter that may have been dynamically important several hundred thousand years after the Big Bang.

Presenter: KAMIONKOWSKY, Marc (Johns Hopkins University)

September 26, 2021 Page 10 GGI Tea Breaks’ … / Report of Contributions Theory Colloquium ”The Hunt for…

Contribution ID: 12 Type: not specified

Theory Colloquium ”The Hunt for the Axion” Wednesday, 3 February 2021 17:00 (1h 30m)

We review the physics case for the axion and discuss different methods to hunt for it in current and future experiments.

Presenter: RINGWALD, Andreas (DESY)

September 26, 2021 Page 11 GGI Tea Breaks’ … / Report of Contributions Theory Colloquium ”Axion Dark …

Contribution ID: 13 Type: not specified

Theory Colloquium ”Axion Dark Matter” Wednesday, 10 February 2021 17:00 (1h 30m)

While providing a simple dynamical explanation for the smallness of CP violation in strong interactions, the QCD axion is also one of the most compelling candidates of dark matter in the Universe. While the presence of relic QCD axions is almost guaranteed if such particle exists, a reliable computation of its abundance is still lacking. Such information could be pivotal in both focusing the experimental efforts and drawing the right theoretical conclusions should such particle be found. In this talk I will review the challenges of such computation and the most recent developments.

Presenter: VILLADORO, Giovanni

September 26, 2021 Page 12 GGI Tea Breaks’ … / Report of Contributions Theory Colloquium ”Tangles to N …

Contribution ID: 14 Type: not specified

Theory Colloquium ”Tangles to Narnia” Wednesday, 17 February 2021 17:00 (1h 30m)

Recently, a new type of holographic pair has been found, in which quantum gravity theories are dual to random ensembles of quantum mechanical systems in one and two dimensions. This dis- covery has revived questions on role of wormholes in quantum gravity and its implications in the holography. I will discuss their generalization in the context of three-dimensional gravity theories. Mathematical theory of knots and hyperbolic geometries associated to them plays an important role.

Presenter: OOGURI, Hirosi (Caltech & Kavli IPMU)

September 26, 2021 Page 13 GGI Tea Breaks’ … / Report of Contributions Theory Colloquium ”The String La…

Contribution ID: 15 Type: not specified

Theory Colloquium ”The String Landscape and the Swampland” Wednesday, 3 March 2021 17:00 (1h 30m)

String theory landscape of vacua point to new consistency conditions that a quantum gravitational system must satisfy. There are only a small number of quantum field theories that satisfy these conditions and all the rest belong to the ‘Swampland’ which cannot be consistently coupled to gravity. In this talk I review some of these conditions and their implications for cosmology and particle physics.

Presenter: VAFA, Cumrun (Harvard University)

September 26, 2021 Page 14 GGI Tea Breaks’ … / Report of Contributions Theory Colloquium ”Gravitational …

Contribution ID: 16 Type: not specified

Theory Colloquium ”Gravitational Wave Astrophysics with LIGO/VIRGO Data” Wednesday, 10 March 2021 17:00 (1h 30m)

I will describe our recent work re-analyzing the GW data made public by the LIGO collaboration. More broadly I will discuss some of the outstanding questions related to binary black hole mergers, what the data might be saying and what we might expect in the near future.

Presenter: ZALDARRIAGA, Matias (Institute for Advanced Study)

September 26, 2021 Page 15 GGI Tea Breaks’ … / Report of Contributions Focus Meeting ”The trouble with H0”

Contribution ID: 17 Type: not specified

Focus Meeting ”The trouble with H0” Wednesday, 17 March 2021 16:00 (1h 30m)

The Hubble constant H0 is one of the most important parameters in the cosmological model,setting the size and age scales of the Universe. The distance ladder relying on supernovae yields values of H0 higher than those inferred from the inverse distance ladder, which is instead based on early- time physics and relies on observations typically involving the cosmic microwave background, in combination with galaxy surveys. Such discrepancy has come to be known as the ‘Hubble tension’. In this Focus Meeting Adam Riess and Licia Verde will illustrate the different methods of measurement of H0, and analyze possible resolutions of the Hubble tension. The Hubble tension has motivated the exploration of extensions to the standard cosmological model in which higher values of H0 can be obtained from CMB measurements and galaxy surveys. The trouble, however, goes beyond H0; such modifications affect other quantities too,such as cosmic times and the matter density. Any Hubble trouble has implications well beyond H0 itself. Licia Verde will analyze the tension in both a model-dependent and a model-independent way, and will propose a new representation of parameter constraints that, hopefully, will help us find a resolution. A streamlined distance ladder constructed from infrared observations of Cepheids and type Ia supernovae with ruthless attention paid to systematics now provides < 2% precision and offer the means to do much better. By steadily improving the precision and accuracy of theHubble constant, we now see evidence for significant deviations from the standard model, referred toas LambdaCDM, and thus the exciting chance, if true, of discovering new fundamental physics such as exotic dark energy, a new relativistic particle, or a small curvature to name a few possibilities. Adam Riess will review recent and expected progress, most recently based on measurements from Gaia EDR3 released in December, 2020.

Presenters: RIESS, Adam (Johns Hopkins University); VERDE, Licia (ICREA)

September 26, 2021 Page 16 GGI Tea Breaks’ … / Report of Contributions Theory Colloquium ”Quantum Gr…

Contribution ID: 18 Type: not specified

Theory Colloquium ”Quantum Gravity meets Statistical Physics” Wednesday, 12 May 2021 17:00 (1h 30m)

Recent work on quantum gravity has revealed deep connections with subjects like quantum information, statistical physics and quantum chaos. In particular, low-energy effective field theories that include gravity turn out to have more access to high-energy degrees offreedom than their non-gravitational Wilsonian counterparts. While precise microscopic high-energy information is inaccessible, certain statistical high-energy information does manifest itself in an interesting way at low energies. I will describe some recent work trying to make this connection more precise, and explain how it connects to issues like wormholes, baby universes, averaging over theories and the black hole information paradox.

Presenter: DE BOER, Jan (Amsterdam University)

September 26, 2021 Page 17 GGI Tea Breaks’ … / Report of Contributions Theory Colloquium ”Generalised R…

Contribution ID: 19 Type: not specified

Theory Colloquium ”Generalised Riemann Hypothesis and Brownian Motion” Wednesday, 16 June 2021 17:00 (1h 30m)

If Number Theory is arguably one of the most fascinating subjects in Mathematics, Theoretical Physics adds to it the standard of clarity, beauty and deepness which have helped us to shape our understanding of the laws of Nature: together, these two subjects present a fascinating story worth telling, one of those vital, wonderful and superb narratives of enquires rarely found in human history. From this point of view, the seminar presents the main features of the Riemann Hypothesis and discusses its generalisation to an infinite class of complex functions, the so called Dirichlet L- functions, regarded as quantum partition functions on the prime numbers. The position of the infinite number of zeros of all the Dirichlet L-functions along the axiswithreal part equal to 1/2 finds a very natural explanation in terms of one of the most basic phenomena in Statistical Physics, alias the Brownian motion. We present the probabilistic arguments which lead to this conclusion and we also discuss a battery of highly non-trivial tests which support withan extremely high confidence the validity of this result.

Presenter: MUSSARDO, Giuseppe (SISSA)

September 26, 2021 Page 18 GGI Tea Breaks’ … / Report of Contributions Reflections on 50+ years of success …

Contribution ID: 20 Type: not specified

Reflections on 50+ years of success stories Wednesday, 7 July 2021 17:00 (1h 30m)

I will share some thoughts prompted by the amazing successes but also by some puzzling aspects of our present description of Nature from the smallest scales of elementary particle physics to the largest ones of gravity and cosmology.

Presenter: VENEZIANO, Gabriele (CERN and College de France)

September 26, 2021 Page 19 GGI Tea Breaks’ … / Report of Contributions Exclusion of de Sitter Vacua and N …

Contribution ID: 21 Type: not specified

Exclusion of de Sitter Vacua and Naturalness Wednesday, 14 July 2021 17:00 (1h 30m)

According to the landscape view, the origin of physical parameters, such as the vacuum energy or the Higgs mass, is linked with the existence of a vast landscape of de Sitter vacua, supposedly provided by quantum gravity. The assumed plentitude of such vacua is a necessary ingredient for anthropic selection. In this talk we shall provide evidence that the situation is actually the oppo- site and that the de Sitter landscape is incompatible with quantum gravity. In this way, quantum gravity/string theory nullifies an outstanding cosmological puzzle of vacuum energy. The exclusion of an eternally inflating Universe raises a number of fundamental questions about pastand future cosmology. It also leads to new predictions about cosmological observables and about the nature of dark energy. The lack of anthropic and cosmological selections sharpens other naturalness questions, such as the weak scale hierarchy and strong-CP violation, and correspondingly strengthens the case for new physics.

Presenter: DVALI, Gia (Ludwig-Maximilians University, Munich)

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