# Seminários do DRCC

Veja a programação:  Seminários DRCC

Abaixo, estão informações e vídeos dos seminários do DRCC que estão no canal do YouTube do DRCC:

#### Seminário de 31/08/2021, (16:00h)

Title: What can we learn from heavy neutron stars?
Speaker:Jaki Noronha-Hostler , University of Illinois Urbana-Champaign

#### Seminar video

Abstract:  The observation of gravitational waves from a blackhole-mystery object binary opens the possibility for heavy neutron stars of 2.5 solar masses (potentially seen in GW190814). If this mystery object is a neutron star of 2.5 solar masses, it poses direct challenges to models of the equation of state. Interestingly, introducing non-trivial structure in the speed of sound sourced by changes in the degrees of freedom (possibly quarks) of ultra-dense matter can resolve this conflict, which may have large ramifications in nuclear and astrophysics. However, for a clear smoking gun signature of the mystery object being a neutron star, one requires a measure of tidal deformability that is non-zero. Because the predicted values are very small, a tenfold increase in sensitivity may be needed to test this possibility with gravitational waves, which is feasible with third generation detectors.”

#### Seminário de 17/06/2021, (16:00h)

Title: The Compressed Baryonic Matter experiment at FAIR
Speaker: Alberica Toia, IKF JW Goethe University, Frankfurt and GSI

#### Seminar video

Abstract:  The study of QCD matter in extreme conditions of temperature and density such as those existing shortly after the Big Bang or in the core of neutron stars brings many insights into the innermost structure of the matter and the forces between its building blocks. While gravitational wave events revealed a glimpse of QCD matter at extreme conditions, the future Facility for Antiproton and Ion Research (FAIR) will directly create and investigate its properties in the laboratory. Nucleus-nucleus collisions at SIS100 beam energies produce very high net-baryon densities, where phenomena such as a first-order phase transition between hadronic and partonic matter or even exotic phases, are expected. The Compressed Baryonic Matter (CBM) is a dedicated heavy-ion experiment designed to explicitly access rare observables sensitive to the medium. For high-statistics measurements of rare probes, event rates of up to 10 MHz are needed. To meet these demands, the CBM experiment uses fast and radiation hard detectors, self-triggered detector front-ends, and a free-streaming readout architecture. Several of the CBM detector systems, the data read-out chain, and event reconstruction are commissioned and already used in experiments during the FAIR phase 0, and also within a full-system setup at GSI SIS18. In this presentation, the physics program of CBM will be reviewed and the current status of the experiment will be reported.

#### Seminário de 27/05/2021, (16:00h)

Title: Odderon discovery
Speaker: Jan Kaspar, CERN and Institute of Physics CAS, Prague

#### Seminar video

Abstract: The seminar will be devoted to the Odderon discovery recently announced by the TOTEM (CERN) and D0 (Fermilab) Collaborations. After introducing the Odderon and related theoretical/phenomenological concepts, I will outline the typical experimental apparatus to study the related phenomena. This will open the path to discussing the main two measurements leading to the discovery: determination of the rho parameter at 13 TeV and comparison of proton-proton and  proton-antiproton cross-sections at 1.96 TeV.

#### Seminário de 13/05/2021, (10:00h)

Title: Quantum mechanics under test in the underground laboratory of Gran Sasso
Speaker: Catalina Oana Curceanu – LNF-INFN, Frascati (Italy)

#### Seminar video

Abstract: We are experimentally investigating possible departures from the standard quantum mechanics predictions at the Gran Sasso underground laboratory in Italy. In particular, with advanced radiation detectors, we are searching for signals coming from a possible violation of the Pauli Exclusion Principle, motivated by quantum gravity models, and we test, with unprecedented sensitivity, collapse models which were proposed to solve the“measurement problem” in quantum physics. In my talk,  I shall present the most recent results we obtained in testing the Pauli ExclusionPrinciple [1] by searching for “impossible” atomic transitions and in testing various types of collapse models by searching the spontaneous emission of radiation, predicted by these models. In particular, I shall discuss our recent results, published in Nature Physics [2] under the title“Underground test of gravity-related wave function collapse”, where we ruled out the natural parameter-free version of the gravity-related model. I shall then present more generic results on testing CSL (Continuous Spontaneous Localization)collapse models and will conclude with future perspectives, both from experimental and theoretical points of view.

#### Seminário de 06/05/2021, (16:00h)

Title: Flavour anomalies at LHCb
Speaker: Elena Graverini, EPFL (Lausanne)

#### Seminar video

Abstract: Although no evidence of new particles has been found in direct searches at the LHC, the motivation for physics beyond the Standard Model (SM) is clear. Recently, important discrepancies in b->sll decays with respect to predictions based on the Standard Model have been measured at LHCb, as well as anomalies in the b->clnu transition. This seminar will review and discuss these anomalies. Opportunities to shed light on the so-called “flavor puzzle” in the near future will be discussed

#### Seminário de 29/04/2021, (16:00h)

Title: A family of successful detectors: liquid Xe Time Projection Chambers
Speaker:  Marcello Messina – Laboratori Nazionali del Gran Sasso

#### Seminar video

Abstract: The XENON collaboration has operated so far a family of Time Projection Chamberswith liquefied Xe of increasing mass and so the sensitivity. The project went from running a small mass detector to prove the detection principle to the most sensitive detector in the field of Dark Mater search in the region of WIMP-nucleon spin-independent elastic scatter cross-section for WIMP masses above 6 GeV/c2, with a minimum of 4.1×10−47 cm2 at 30 GeV/c2 and 90% confidence level. The extremely good performance shown by the XENON1T detector allowed to search for possible new physics in different channels such as solar axions, an enhanced neutrino magnetic moment, and bosonic dark matter. The topics mentioned above will be treated in details.

#### Seminário de 15/04/2021, (16:00h)

Title: Strange nuclear physics at the LHC: at the frontiers of the standard model
Speaker:  Laura Fabietti – TUM/Munich

#### Seminar video

Abstract: Hadrons interact via a residual strong force that is unmeasured for most hadron species. The measurement and quantitative understanding of the strong interaction among hadrons are considered to be one of the frontiers within the standard model of nuclear and particle physics. Not only the interaction studies are important to understand the strong interaction in detail, but their knowledge has important implications for the equation of the state of neutron stars. The ALICE collaboration recently demonstrated that by combining excellent particle identification and a momentum correlation analysis method applied to pp and pPb collisions at the LHC, it is possible to measure the strong interaction among all hadrons containing strange quarks and protons. In this talk,  I will discuss the recent measurements carried out in this sector that allowed us to measure with unprecedented precision the following interactions: K^p, pLambda, pSigma, pXi^an pOmega^. The measured correlation functions can be used to test predictions from chiral effective field theory or lattice calculations for different channels and so far unknown features of the strong interaction will be discussed. The consequences for the physics of neutron stars will be presented. These measurements open a new avenue in nuclear physics, with the potential of accessing the strong force between any hadron pair.

#### Seminário de 08/04/2021, (10:00h)

Title: Some attempts to the chiral magnetic effect with inhomogeneous electromagnetic fields
Speaker:  Kenji Fukushima – Universidade de Kyoto

#### Seminar video

Abstract:  It is a longstanding problem how to probe the chiral anomaly with physical observables.  The chiral magnetic effect is a promising candidate and the theoretical understanding has been advanced for a simple case with constant electromagnetic backgrounds. In the first half of my talk. I will make a pedagogical overview of the idea, the status, and the remaining problems.  In the last half of my talk, I will discuss a description of the current generation in terms of particle production, which can be solved for constant electromagnetic backgrounds again, but it is still very challenging to tackle temporal and spatial inhomogeneous situations.  I will introduce some attempts of ours using a standing wave profile of the electromagnetic fields.

#### Seminário de 04/12/2020, (11:00h)

Title: Dissecting the Guts of the Proton
Speaker:  Matt Sievert (New Mexico State University)

#### Seminar video

Abstract: Since the discovery of the atom and the proton a century ago, our knowledge of atomic structure and the electromagnetic force has advanced to astronomical precision. But to this day, our knowledge of the internal structure of the proton is sporadic and incomplete, with fundamental questions about the origin of the proton mass and spin still unanswered. These persistent questions and challenges reflect the beautiful, emergent complexity of the nuclear force itself. In this talk I will present an overview of the nuclear force known as Quantum Chromodynamics and the experimental programs to study it in two distinct regimes: in the plasma state at high temperatures produced in heavy-ion collisions, and “in situ” within the proton using the forthcoming Electron-Ion Collider — the most powerful electron microscope ever created.

#### Seminário de 27/11/2020, (11:00h)

Title: Applying and understanding (Very) Deep Learning for physics
Speaker:  Olena Linnyk (Frankfurt Institute of Advanced Studies, Milch & Zucker)

#### Seminar video

Abstract: Let us open the Black Box! Deep Learning is the game changing technology behind the chatbots, DeepL, diagnostic apps as well as fast detector simulations, online calibration and systematic uncertainty reduction. What is Deep Learning and Very Deep Learning and how does it differ from the traditional Machine Learning and rule-based AI? Are there ways to look under the hood and explain the decisions of a deep net? You will see the new research fields opening up and understand,why do I think that the best data scientists are physicist.

#### Seminário de 20/11/2020, (11:00h)

Title: Upper limits on the total cosmic-ray luminosity of individual
sources from gamma-rays
Speaker:  Rita Cassia Dos Anjos (UFPR)

#### Seminar video

Abstract: The upper limit on the integral flux of GeV–TeV gamma-rays is used to extract the upper limit on the total UHECR luminosity of individual sources. The correlation between the upper limit on the integral GeV–TeV gamma-ray flux and the upper limit on the UHECR luminosity is established through the cascading process that takes place during the propagation of the cosmic rays in the background radiation fields. The measured upper limit on the GeV–TeV gamma-ray flux is restrictive enough to allow the calculation of an upper limit on the total UHECR cosmic-ray luminosity of five sources. The upper limit on the UHECR cosmic-ray luminosity of these sources is shown for several assumptions on the emission mechanism. The construction of the CTA Observatory will increase the number of observed sources and enhance the sensitivity of the measurements significantly in the next years. The combination of this multi-messenger information to come is certainly going to shed light on the puzzle of UHECR generation.

#### Seminário de  06/11/2020, (11:00h)

Title: Chiral vortical effect
Speaker:  Andrey Sadofyev (Los Alamos National Laboratory)

#### Seminar video

Abstract: Chiral effects are new transport phenomena in systems of massless fermions which are argued to be macroscopic manifestations of the axial anomaly. The anomaly is quantum in its nature and so are the chiral effects being similar in this sense to superfluidity and superconductivity. They attracted significant attention in the literature appearing in a variety of systems from Dirac semimetals to quark-gluon plasma. Among these phenomena, there is a class of effects caused by the medium rotation — chiral vortical effects (CVE), which are related to the spin polarization. In this overview talk, I will discuss the relation of the CVEs to the anomalies and tell about new examples of vortical responses in chiral media.

#### Seminário de  23/10/2020, (11:00h)

Title: The electron-ion collider: A collider to unravel the mysteries of visible matter
Speaker:  Elke-Caroline Aschenauer (Brookhaven National Laboratory)

#### Seminar video: It is not available

Abstract:

Understanding the properties of nuclear matter and its emergence through the underlying partonic structure and dynamics of quarks and gluons requires a new experimental facility in hadronic physics known as the Electron-Ion Collider (EIC). The EIC will address some of the most profound questions concerning the emergence of nuclear properties by precisely imaging gluons and quarks inside protons and nuclei such as their distributions in space and momentum, their role in building the nucleon spin, and the properties of gluons in nuclei at high energies. In January 2020 the EIC received CD-0 and Brookhaven National Laboratory was selected as site. This presentation will highlight the capabilities of an EIC and discuss the accelerator design and the concepts for the experimental equipment.

#### Colóquio extraordinário da Pós-Graduação  09/19/2020, (11:00h)

Title: Neutrinos e a busca por física além do modelo padrão
Speaker:  Pedro Pasquini (JiaoTong University, Shangha)

Seminário baseado na tese de doutorado de Pedro Pasquini que ganhou o prêmio de melhor tese de 2019 em Física/Astronomia – CAPES.

#### Seminar video

Abstract: Os neutrinos foram propostos por Pauli em 1930 através de uma carta na qual ele afirma “Essa é uma ideia que eu não ouso publicar”, pois era uma partícula impensavelmente difícil de se detectar. Hoje, 90 anos depois, os neutrinos já renderam mais de 5 prêmios Nóbel e tomam um papel central na física de partículas de fronteira. Mas o que uma partícula já tão estudada pode trazer de novo? Uma das poucas evidências de física além do modelo padrão: A sua massa! É através dela que podemos explorar fenômenos que não podem ser alcançados por grandes aceleradores, mas podem ajudar a resolver problemas em aberto tanto na física de baixas e altas energias e ajudar até a entender o universo primordial.

#### Seminário de  25/09/2020, (11:00h)

Title: Evidence for Higgs boson decay to a pair of muons
Speaker:  Raffaele Gerosa (CERN)

#### Seminar video

Abstract: Probing the Higgs boson coupling to the muon is one of the last experimentally accessible frontiers In the direct measurement of Higgs boson couplings at the LHC. This seminar will highlight the first evidence for the rare Higgs boson decay to muons, achieved by the CMS Collaboration using the full dataset collected at 13 TeV during Run-2 of the LHC. This milestone was achieved earlier than expected thanks to the excellent performance of the CMS detector, with high precision tracking and muon reconstruction systems, and also through the development of novel analysis strategies that include intensive use of machine learning techniques. The first set of measurements of the Higgs boson properties through the muon decay channel is also presented, with the observed signal well consistent with the standard model predictions. Finally, prospects for this measurement at the HL-LHC are reported

#### Seminário de 02/09/2020 (16h)

Title: Neutrino physics, Dark matter and U(1) symmetries

#### Seminar video

Abstract: Neutrino masses and the existence of non-baryonic Dark Matter (DM) are, together with the Baryon asymmetry in the Universe, three pieces of evidence that the Standard Model is not the final theory to describe our nature. In this talk, I will discuss scenarios where the generation of neutrino masses and its Dirac/Majorana nature are linked to the DM sector. In particular, I will focus on scenarios where the connection is coming from a U(1) symmetry, either an anomaly free B-L or the Peccei-Quinn symmetry. I will also discuss scenarios with a U(1)´ gauge symmetry in the light of COHERENT data.

#### Seminário de 19/08/2020 (16h)

Title: Precision measurements in the DUNE Near Detector Complex
Speaker: Zahra Tabrizi, Virgina Tech University

#### Seminar video

Abstract: The experimental confirmation of the oscillation of neutrino flavors in the last 2 decades has been a milestone in clarifying the framework of particle physics. Some of neutrino properties can be explained through the current rich data of the neutrino experiments; however, there are still important unanswered questions which need to be clarified. Next-generation, long-baseline neutrino oscillation experiments are under serious consideration to answer these questions. The unprecedented neutrino fluxes at these experiments make them suitable for precision calculations of the SM predictions as well as searching for light new physics (NP) via measurements of the trident production and neutrino scattering off electrons and nuclei in the near detectors. We provide estimates of the number and distribution of neutrino-electron scattering and trident events at the DUNE near detector, and use them to study the weak angle. We then use these neutrino scatterings to probe leptophilic  light Z’ models. Finally, we quantify the DUNE sensitivity to dimension-6 operators in the SMEFT parameters.

#### Seminário de 05/08/2020 (16h)

Title: LHCb discovery of J/psi-J/psi mass structure
Speaker: Tomasz Skwarnicki, Syracuse University

#### Seminar video

Abstract: The LHCb experiment has reported a significant structure in invariant mass distribution of promptly produced J/psi J/psi combinations, with a peak at 6.9 GeV, which is a good tetraquark candidate. I will discuss this discovery in a broader context of tetraquark and pentaquark candidates observed by the LHCb and other experiments.

#### Seminário de 22/07/2020 (16h)

Title: Insights into Scattering from symmetries and the Infrared
Speaker: Monica Pate – Harvard

#### Seminar video

Abstract: The scattering problem has served as the arena for significant breakthroughs in modern high-energy physics, including the discovery of the Standard Model, and thereby become a pillar of the field. Exhibiting rich mathematical structure while maintaining direct experimental significance, the scattering problem is amenable to a variety of approaches, whose combination has been advantageous historically. While scattering experiments that probe the quantum nature of gravity are beyond our present day capabilities, the theoretical question remains well-posed and a definitive answer would have profound implications for our understanding of the microscopic structure of the universe. In this talk, I will describe a recently-discovered new class of symmetries of the scattering problem in theories of gauge and gravity. These symmetries are infinite numbers and as a result imply an infinite number of constraints.The constraints have been identified with the so-called soft theorems from quantum theory which characterize low-energy limits of scattering amplitudes. Finally, I will describe a new proposal for holography of quantum gravity in asymptotically flat spacetimes that was motivated by these new symmetries.

#### Seminário de 08/07/2020 (16h)

Title: Neutrino Physics with High-Energy Cosmic Neutrinos
Speaker: Mauricio Bustamante, Nordita

#### Seminar video

Abstract: The cosmic neutrinos discovered by IceCube are doubly unique: they have the highest detected neutrino energies — up to a few PeV — and travel the longest distances — up to a few Gpc, the size of the observable Universe. These features make them attractive probes of particle-physics properties, possibly tiny in size, at energy scales unreachable by other means. In the decades before the IceCube discovery there were plenty of proposals of prospective studies using high-energy cosmic neutrinos. Today, these proposals have become a reality. I will showcase examples of testing neutrino physics at these scales, including stringent tests of physics beyond the Standard Model, like new neutrino-neutrino interactions and neutrino decay.

#### Seminário de 24/06/2020 (16h)

Title: Quark matter cores in massive neutron stars
Speaker: Aleksi Vuorinen, University of Helsinki

#### Seminar video

Abstract: Confirming or ruling out the existence of deconfined quark matter inside at least some neutron stars is a classic open problem in nuclear astrophysics. While the ultimate goal continues to be the observation of a smoking gun signal directly indicating the presence or creation of quark matter, a more indirect approach to the problem has lately become feasible. By combining ab-initio theoretical results for the microscopic properties of dense QCD matter with the latest astrophysical measurements of neutron star properties, it is possible to build stringent model-independent constraints for the material properties of
neutron-star matter at different densities. Presenting results from a very recent analysis of this kind, we argue that matter in the cores of the heaviest stable neutron stars has characteristics considerably closer to the predicted properties of deconfined quark matter than those of nuclear matter. The implications of the finding as well as potential ways of improving its accuracy are also discussed.

Baseado na publicação no periódico Nature,

#### Seminário de 17/06/2020 (16h)

Title: Indications for the Chiral Magnetic Effect in Ion-Ion collisions at RHIC
Speaker: Roy Lacey, State University of New York at Stony Brook

#### Seminar video

Abstract: Validation of the Chiral Magnetic Eect (CME) in the magnetized chiral relativistic quark-gluon plasma (QGP) produced in heavy-ion collisions, can provide key insights into anomalous transport in the QGP and the connections between chiral symmetry restoration, axial anomaly and gluonic topology in QCD. Charge separation measurements play a pivotal role in ongoing searches for the Chiral Magnetic Eect (CME). Recently, a charge-sensitive correlator RΨm (∆S) [1], designed to discern between background- and CME-driven charge separation, was used to carry out a detailed set of measurements, relative to both the 2nd- (Ψ2) and 3rd-order (Ψ3) event planes, for several collision systems (A+A(B)). The measurements indicate nearly at to convex h RΨm (∆S) distributions for the measurements relative to Ψ3 and those relative to Ψ2 for the p(d)+Au systems, consistent with the essentially random B field orientations for these measurements. By contrast, the A+A measurements relative to Ψ2, show concave-shaped RΨ2 (∆S) distributions which validate CME-driven charge separation. Quantication of the latter signals via the the P-odd Fourier dipole coecient a˜1, indicate an increase from a˜1 = 0.50±0.025% in central collisions to a 1 = 2.0±0.1% in peripheral collisions, consistent with the expected patterns for a robust but small CME signal.

#### Seminário de 03/06/2020 (16h)

Title: Decades of excitement! Why we remain enthusiastic about multimessenger science with gravitational-waves?
Speaker: Szabolcs Márka (Columbia University in the City of New York)

#### Seminar video

Abstract: The discovery of gravitational waves and their multimessenger fingerprint has opened tremendous opportunities for astrophysics. Extraordinary instrumental breakthroughs in gravitational-wave detectors on Earth and in Space, in electromagnetic and in neutrino observatories lead to an information explosion, rapidly expanding humanity’s cosmic and scientific horizons. In this talk, I will discuss the history and promise of seamlessly integrating data streams of gravitational-wave, neutrino, and electromagnetic  observatories. I will elaborate on the evolution of the idea that multimessenger science can lead to a uniquely precise understanding of the astronomical sources and the underlying physical processes.
Multimessenger astrophysics with gravitational-waves has a rich history that I will also describe. LIGO, Virgo, Kagra, and LISA invested in multimessenger astrophysics for decades, and it shall open new windows
on the universe that I will highlight.

#### Seminário de 20/05/2020 (16h)

Title: Quantum Gravity
Speaker: Francesca Vidotto, University of Waterloo Ontario

#### Seminar video

Abstract: Loop Quantum Gravity provides a well defined tentative framework to describe the quantum properties of gravity. I will describe how the theory preserve and built on the fundamental properties of general relativity and quantum theory, presenting the main ideas and results. The theory, now thirty years old, is built upon a compelling mathematics and exploits techniques close to those used in lattice gauge theory and for many-body systems. One of the main aspect of the theory is the absence of curvature singularities, that leads to a rich phenomenology in cosmology and for black holes: I will conclude presenting some recent ideas about possible astrophysical detections of quantum gravitational effects.

#### Seminário de 13/05/2020 (16h)

Title: Probing Ultra-strong Electromagnetic Fields with the Breit-Wheeler Process
Speaker: Daniel Brandenburg (BNL)

#### Seminar video

Abstract: Ultra-relativistic heavy ion collisions are expected to produce some of the strongest magnetic fields ($10^{13}-10^{16}$ Tesla) in the Universe[1]. Recently, there has been increased interest in the  magnetic fields produced by heavy ion collisions and their possible observational impacts through emergent magnetohydrodynamical phenomena in Quantum Chromodynamics, like the Chiral Magnetic Effect[2]. The initial strong electromagnetic fields produced in heavy-ion collisions have been proposed as a source of linearly-polarized, quasi-real photons[3] that can interact via the Breit-Wheeler process to produce $e^+ e^-$ pairs[4].

In this talk I will present STAR measurements of $e^+ e^-$ pair production in ultra-peripheral and peripheral Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV. A comprehensive study of the pair kinematics is presented to distinguish the $\gamma\gamma \rightarrow e^+ e^-$ process from other possible production mechanisms.

Further, the measured distribution of $e^+e^-$ pairs reveals a striking fourth-order angular modulation which is a direct result of vacuum birefringence[5], a phenomenon predicted in 1936 in which empty space can split light according to its polarization components when subjected to a strong magnetic field.

Together these measurements provide the first direct experimental evidence of QED phenomena that have waited nearly a century for confirmation. Additionally, they show that ultra-relativistic heavy-ion collisions are capable of producing magnetic fields approximately 10,000 times stronger than the those in the magnetosphere of neutron stars (inferred to be $\approx 10^{10}-10^{12}$ Tesla), the strongest magnetic fields in the known Universe until now.

[1] V. Skokov, A. Illarionov, and V. Toneev. International Journal of Modern Physics A 24 (2009): 5925–32.
[2] Kharzeev, D. E., et al. Prog. Part. Nucl. Phys., 88 (2016)1–28
[3] C. Weizsäcker, Zeitschrift für Physik 88 (1934): 612–25.
[4] G. Breit and J. A. Wheeler. Physical Review 46 (1934): 1087
[5] Heisenberg, W., and H. Euler. Zeitschrift für Physik, (1936) arXiv: physics/0605038

#### Seminário de 29/04/2020 (16h)

Title: Higgs inflation
Speaker: Syksy Rasanen, Universidade de Helsinki

#### Seminar video

Abstract: Inflation is the most successful scenario for the early universe. It may be possible to realise it using the Standard Model Higgs without any new degrees of freedom. This proposal is simple at heart, but involves subtle complications both on the side of quantum theory and the theory of gravity.

#### Seminário de 22/04/2020 (16h)

Title: Properties of strongly interacting matter from first principles
Speaker: Claudia Ratti (University of Houston)

#### Seminar video

Abstract: Quantum Chromodynamics (QCD) is the fundamental theory describing the interactions between the ultimate building blocks of matter, namely quarks and gluons. At temperatures as high as trillions of degrees Kelvin and zero net baryon density, first principle Lattice QCD calculations have shown that a smooth crossover transition occurs between hadronic matter and a new state of matter called the quark-gluon plasma. A remaining question in QCD is whether criticality may appear at large baryon densities. In this talk I will review the status of lattice QCD simulations of strongly interacting matter at zero and finite density. I will also discuss ways to push our investigations to larger baryon densities, to support the forthcoming experimental program at Brookhaven National Laboratory.

#### Seminário de 08/04/2020

Title: Subatomic vortices
Speaker: Francesco Becattini (INFN Florence)

#### Seminar video

Abstract: The experiment STAR at the Relativistic Heavy Ion Collider at Brookhaven  reported in 2017 the evidence of a global polarization of Lambda and anti-Lambda hyperons of the order of a percent in the collisions of nuclei at very high energy at finite impact parameter. This effect – which was predicted on the basis  of the formation of the QCD plasma at local thermodynamic equilibrium – is a striking confirmation of the fluid nature of the femtometer-scaled system formed in such collisions and, particularly, of its finite vorticity, estimated o be of the order of 1021 sec-1.  In this seminar, I will address the main results, the theoretical framework to deal with spin effects in relativistic fluids, and the possible developments.