Grad School Physics Seminar 2022/23

Europe/Warsaw
Room 207 (NCBJ)

Room 207

NCBJ

Pasteura 7
Jakub Wagner (National Centre for Nuclear Research), Katarzyna Malek (NCBJ), Michal Bluj (NCBJ)
Description

Physics seminar of the Graduate School of NCBJ.

GoToMeeting link for the seminar: https://app.gotomeeting.com/?meetingId=434622613

    • 09:15 09:35
      Welcoming talk of the Graduate School director 20m
      Speaker: Prof. Michał Spalliński (NCBJ)
    • 09:35 09:55
      Discussion about the goals and organization of the PhD seminar 20m
      Speaker: Jakub Wagner (National Centre for Nuclear Research)
    • 09:15 10:15
      Constraints on U(1)` solutions to the flavor anomalies with trans-Planckian asymptotic safety 1h

      The Standard Model is a very successful theory. However, few of the observed phenomenon is at odds with the current fundamental theory. One such discrepancy is observed in the rare decays of B-meson decays which are referred as flavor anomalies. In this talk, I will discuss flavor-anomaly solutions with U(1)` extensions in the framework of asymptotically safe quantum gravity. The universal contribution of quantum gravity to renormalization group equations (RGEs) of all the gauge and the Yukawa couplings, beyond the Planck scale, ensues interdependent boundary conditions between the Standard Model and the New Physics (NP) couplings during the flow of RGEs from an interactive UV fixed point. As a result, precise measurements of low-energy SM couplings fix the exact values of the NP couplings, and accordingly, the NP mass range can be significantly narrowed down. We confront the models parameter space with the various LHC searches for VL fermions and the new gauge boson Z'. We find a viable parameter space with a potential to probe entirely in LHC Run 3.

      Speaker: Abhishek Chikkaballi
    • 09:15 10:15
      Trouble in the early Universe: why is it so dusty out there? 1h

      An increase in the observation facilities in the last two decades, from the UV to far-infrared and sub-millimeter, has motivated a multi-wavelength approach to studying the Universe. With higher resolution and in-depth surveys of the sky, we are now able to study distant galaxies and estimate their physical parameters, e.g. star formation Rate (SFR), stellar mass and dust mass by "looking back in time". In this work, we build a catalog of Dusty Star-Forming Galaxies (DSFGs) located at a redshift of 1.9 < z < 6.9, when the Universe was between 0.8 and 3.5 Giga years old, by cross-matching the existing data from the UV to the far-infrared, and we derive their physical parameters. The information derived allows us to probe the baryon evolution of these galaxies by using chemical evolution models. In particular, we test the hypothesis of different Initial Mass Functions (IMFs) of stars, which affect the chemical enrichment of the interstellar medium of galaxies as well as the derivation of the physical parameters of galaxies.

      Speaker: Mr Prasad Sawant (National Centre for Nuclear Research, Poland)
    • 09:15 10:15
      Nuclear chirality & lifetime experiment 1h

      Chirality in nuclear excited states involves spontaneous symmetry breaking of time-reversal T operation. This phenomenon is quite new as the first experimental proof of existence of chirality was given in 2006 by Warsaw team and only in 7 isotopes with chiral states have been found so far. The tool to detect and trace chirality is experimental nuclear gamma spectroscopy. On the seminar I will introduce chirality phenomenon, show experimental ways to detect it, and tell about the experiment held in the Warsaw Heavy Ion Laboratory in July 2022 titled “Search for chiral to not chiral transition by lifetime measurement of I=10+ state in 128Cs with a PLUNGER technique.

      Speaker: Adam Nałęcz-Jawecki (NCBJ)
    • 09:15 10:15
      Vector-Like fermions and Z’ as candidates for New Physics 1h

      The pursuit for physics beyond the Standard Model (BSM) follows a twofold path. On the experimental side, a great effort was put in developing research strategies that go beyond the original LHC paradigm based on the missing transverse energy. On the theoretical side, various BSM models can be proposed to address phenomena observed in nature. Among many extensions of the Standard Model, scenarios with vector-like (VL) fermions and Z' have long been enjoying a lot of interest. In this presentation I will talk about two different models with VL-fermions and Z'. In the first model I use the framework of Trans-Planckian Asymptotic-Safety to reduce the number of free parameters of a minimal model with VL-fermions and Z'. In the second model I scan the parameter space of a slightly modified version of the type-II next-to-2HDM. One of the main features of this second model is that masses for SM particles are generated via the so-called Seesaw mechanism.

      Speaker: Daniele Rizzo (National Center for Nuclear Research (NCBJ), Warsaw, Poland)
    • 09:15 10:15
      Lighting up the black box - explainable ML in Astrophysics 1h

      The development of new all-sky and large-area astronomical surveys gives a chance for new insights in astrophysics. However, these recent generation surveys are flooding astronomers with data, giving an exponential growth - with respect to previous surveys - of data collected per night (for instance, 90 TB/night for the Thirty Meter Telescope). For some tasks, i.e. object detection, classical methods or human detection need to be faster to cover the totality of the data collected. At the same time, Machine learning (ML) keeps showing the scientific community its ability to solve astrophysical problems.
      In this talk, I will show some ML applications on astrophysical data in different domains: time and frequency domain gravitational waves (GW) data, strong lenses detection (images), and astronomical text interpretation. The emphasis will be put on analysis related to Strong gravitational lensing and on the importance of having explainable Artificial Intelligence. Strong gravitational lensing is useful to constrain cosmological parameters, even though it is a rare phenomenon in astrophysics. For this reason, strong lens seekers are training their ML models on simulations. We will show how simulation-trained models behave with survey data, interpret the results and discuss techniques that might help us research new candidates. Finally, I will discuss possible applications of Interactive ML for object detection.

      Speaker: Margherita Grespan (NCBJ)
    • 09:15 10:15
      Hyperon non-leptonic decays in χPT, revisited 1h

      Though weak non-leptonic decays of hyperons - strange baryons - have been investigated before, an update is urgently needed in view of recent significant measurements from the BESIII collaboration. Only with such an update, future high-precision data of weak non-leptonic decays can be properly interpreted. Such hadronic decays are characterized by two distinct contributions to the decay amplitude, called S- and P-wave.
      Within the framework of chiral perturbation theory (χPT), such L-wave amplitudes can be computed: we do so up to one-loop corrections, noting also that in recent years their relative size to the tree-level contributions was differently interpreted. The general consensus is that weak non-leptonic hyperon decays are characterized by two contributions with polar behavior under approximate SU(3) symmetry.
      This project aims at reviewing such calculations in the light of the recent updates on the measurement of the decay parameter αΛ, directly connected to the above-mentioned spherical-wave amplitudes. A recalculation of such lowest order contributions and their corrections is hence needed, since it might lead to a new level of agreement with experiment. As an additional bonus, our aspiration is to reduce the numerous different approaches to the best fitting description of such decays.

      Speaker: Nora Salone
    • 09:15 10:15
      Exclusive processes, factorization and parton distributions 1h

      For a long time, it was believed that the fundamental constituents of atoms were electrons and nucleons until experiments conducted in the 1960s at Standford Linear Accelerator Center (SLAC) proved the existence of internal degrees of freedom in the nucleons. These ones are called quarks and gluons, or collectively partons. With QCD as the fundamental theory for strong interactions, we can describe hadronic structure via correlators of partons giving rise to the so-called parton distribution functions (PDFs) and generalized parton distributions (GPDs). The non-elementary nature of hadrons makes these correlators perturbatively unsolvable so we can only measure or model them. On top of this, PDFs and GPDs appear when studying two different types of QCD processes: inclusive and exclusive. Among all known processes of these two types, there is an exclusive scattering named double deeply virtual Compton scattering (DDVCS) that allows to measure GPDs in their whole domain.

      In this seminar, I review the differences between inclusive and exclusive processes with special attention to DDVCS for which my group and I have obtained a new analytical formulae useful to study its feasibility in JLab and EIC experiments.

      Speaker: Victor Martinez-Fernandez
    • 09:15 10:15
      A family tree of galaxies 1h

      In my talk, I will present work on identifying mergers of galaxies using astronomical data in optical bands. The current models of galaxy formation and evolution, in the context of the Lambda-CDM cosmological model, are based on dark matter haloes that host a galaxy. Merging galaxies are one crucial aspect of the galactic life-time whose effect is still not fully understood. Identifying them is therefore the research first step. Two projects will be presented: first the use of image recognition methods with a Convolutional Neural Network (CNN) together with morphological parameters on the North Ecliptic Pole (Pearson, Suelves et al. 2022). This provided the community with a catalogue of mergers in one region of the sky with a wealth of data across the electromagnetic spectrum. The second is the application of a Neural Network (NN) applied on photometric information (Suelves, Pearson \& Pollo 2022). This NN provided us with a previously unknown tracer of merging processes, the error in the sky background calculation. With it, we aim to make merger finding techniques more efficient and less prone to mistakes due to the complexity of the night sky.

      Speaker: Luis Eduardo Suelves (NCBJ)
    • 09:15 10:15
      In search of precision in QCD at high energy physics: beyond eikonal order 1h

      Studying high-energy hadronic scattering processes to understand the interior of atoms has been the focus of experimental and theoretical studies for more than three decades now. During this period, the Color Glass Condensate(CGC) effective field theory has been utilised to analyse specifically high-energy proton-nucleus (pA) collisions. One of the main approximations used in the CGC is the so-called eikonal approximation, which amounts to neglecting power-suppressed corrections in high-energy limits. For high-energy colliders like LHC, this is a good enough approximation. But the corrections beyond eikonal approximation can be sizable at intermediate energies, in particular at relativistic heavy ion collider (RHIC) and upcoming electron ion collider (EIC). In this talk, I will briefly review the eikonal approximation and present the computation of a gluon propagator through the target at next-to-eikonal accuracy.

      Speaker: Swaleha Mulani (National Centre for Nuclear Research(NCBJ), Warsaw, Poland)
    • 09:15 10:15
      Studying CPT with Neutral Mesons - Standard Model Extension Approach (SME) 1h

      The Standard Model of particle physics (SM) is the embodiment of our current understanding of the sub-atomic Universe and describes all fundamental forces except gravity. Despite its success, the SM has a few shortcomings. Apart from not including the description of gravity, it fails to explain the scale of the observed matter-antimatter imbalance and does not give the rationale behind the apparent non-zero neutrino masses. These problems are at the core of particle physics research today, as even a minor deviation from the SM (such as CPT violation) would be a breakthrough suggesting the existence of a more fundamental theory beyond the SM (BSM). The BSM effects are expected to be very small, for example at the Planck scale.

      Fortunately, physics at the scale approaching the Planc scale can be tested with existing technology through the search for spacetime-symmetry violation. The realisation of this fact brought about the development of a comprehensive framework, known as the Standard Model Extension (SME). It was set up for studying deviations from exact Lorentz and CPT symmetries. This framework can be successfully applied to studies of CPT violation (CPTV) in neutral meson oscillations. Where the order of magnitude of results of CPTV measurements with neutral kaons approaches an interesting region of m^2_{K}/M_Planck=2*10^{-20} GeV. In my talk, I will try to outline the basic notions regarding the theoretical description of neutral meson oscillations, as well as, the key concepts behind the analysis regarding the search for CPT breaking in the charm sector.

      Speaker: Mateusz Kmieć (NCBJ)
    • 09:15 10:15
      Gravitational wave lensing in General Relativity and beyond 1h

      Gravitational lensing has been considered as a rare phenomenon, however recent advancements in technology lead to the discovery of many lensed events. Now it has become an unavoidable tool in astronomy. Like electromagnetic waves, gravitational waves could also be lensed leading to the formation of magnified multiple signals and many more. The increasing sensitivity of current detectors and planned next-generation detectors makes the future of gravitational wave astronomy looks promising. In this talk, I will present some of the interesting predictions of lensed gravitational waves and how such lensed events can be used to test modified theories of gravity.

      Speaker: Sreekanth Harikumar (National Centre for Nuclear Research(NCBJ))
    • 09:15 10:15
      Estimating detector systematics at T2K's far detector: A neutrino oscillation adventure 1h

      T2K is a long-baseline neutrino experiment that measures neutrino oscillations. Oscillation of the muon (anti)neutrino beam to electron (anti)neutrinos is sensitive to the leptonic CP violating phase. In this talk, I will discuss the addition of a new electron neutrino signal sample at T2K's far detector, which can improve T2K's sensitivity to the CP-violating phase. I will also talk about how the systematic errors at T2K's far detector are estimated using Markov Chain Monte Carlo techniques, along with some outlook to future studies.

      Speaker: Yashwanth S. Prabhu (NCBJ Warsaw)
    • 09:15 10:15
      Quark-gluon plasma in magnetic fields 1h

      The impact of the electromagnetic field in the presence of strong interactions is usually not considered, as it plays a negligible role. However, the electromagnetic field becomes visible when its size is characteristic for strong interactions ( $eB \sim m_\pi^2$ ). It is not accessible experimentally to create such strong magnetic field. Nevertheless, it is expected that a field of a very large amplitude can briefly arise in relativistic heavy ion collisions, and be sustained by induced electric currents in the quark-gluon plasma created during the collision of ions. The project aims to analyze the electromagnetic field generated in relativistic heavy ion collisions and understand why its influence on various observables is not observed experimentally. The research project will include a discussion of aspects that have not been analyzed so far, such as formulating the problem of generating an electromagnetic field as an initial value problem, and analyzing the behavior of the quark-gluon plasma in said field. The main goal is to take into account non-equilibrium effects by properly setting the initial conditions.

      Speaker: Patrycja Słoń
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