## SEMINARIUM FIZYKI WIELKICH ENERGII

SEMINARIUM FIZYKI WIELKICH ENERGII

Dnia 29 maja (piątek) o godzinie 10:15, odbędzie się seminarium, na którym zostanie wygłoszony referat pt.:

Prospects of searches for long-lived SUSY and doubly charged particles with MoEDAL experiment

Referuje: mgr Rafał Masełek (IFT)

Abstract:

The Monopole & Exotics Detector at the LHC (MoEDAL) is a small experiment designed to search for highly ionising avatars of a New Physics. Its main goal is to study the possible existence of magnetic monopoles, but the physics program defines over 34 distinct scenarios, targeting extra dimensions, new symmetries, topological particles and Dark Matter.

Currently, MoEDAL experiment is being upgraded to prepare for Run-3 data taking period. In my talk, I present the prospects of searches for New Physics after the upgrade. I discuss detection reach for various types of long-lived Supersymmetry and doubly charged particles, and I compare it to the results by ATLAS and CMS.

Serdecznie zapraszamy

dr hab. Katarzyna Grzelak
prof. dr hab. Jan Królikowski
prof. dr hab. Aleksander Filip Żarnecki

The meeting will take place on zoom.us platform.

https://us02web.zoom.us/j/176261850?pwd=cWgzMkwvVjBTSm5ObTFMSnBPTndIQT09

Zoom meeting ID: 176 261 850

## SEMINARIUM FIZYKI WIELKICH ENERGII

SEMINARIUM FIZYKI WIELKICH ENERGII

Dnia 22 maja (piątek) o godzinie 10:15, odbędzie się seminarium, na którym zostanie wygłoszony referat pt.:

Modern techniques of ultra-high energy cosmic rays detection.

Referuje: dr hab. Jarosław Stasielak (IFJ)

Abstract:

Studies on ultra-high energy cosmic rays, those exceeding energy $10^{18}$ eV, are conducted with giant ground-based detectors recording extensive air showers (cascades of secondary particles) induced by cosmic ray particles in the atmosphere. Over recent years, these studies have dramatically advanced our understanding of ultra-high energy cosmic rays. Nevertheless, the results obtained so far neither allow us to determine the sources of these most energetic particles we know in the Universe nor to explain the origin of the observed cosmic ray flux suppression above $4\times 10^{19}$ eV. The explanation of these puzzles is one of the most important goals of modern astrophysics. At the same time, the results obtained indicate that further advances in research on ultra-high energy cosmic rays require improving measuring capabilities of detectors. Therefore, there is a special need to search for new experimental solutions to improve the accuracy of measurements of extensive air showers, while reducing the costs of construction and operation of detectors. I will present modern techniques for the detection of ultra-high energy cosmic rays, both classic well-proven methods as well as the new radio detection method, intensively developed over the last decade, which is currently considered the most promising technique. As examples of works on alternative methods of extensive air shower detection, the microwave and radar detection techniques will be discussed. Also I will present the main goals and plans for the upgrade of the Pierre Auger Observatory — the largest detector of ultra-high energy rays.

Serdecznie zapraszamy

dr hab. Katarzyna Grzelak
prof. dr hab. Jan Królikowski
prof. dr hab. Aleksander Filip Żarnecki

The meeting will take place on zoom.us platform.

https://us02web.zoom.us/j/176261850?pwd=cWgzMkwvVjBTSm5ObTFMSnBPTndIQT09

Zoom meeting ID: 176 261 850

## SEMINARIUM FIZYKI WIELKICH ENERGII

SEMINARIUM FIZYKI WIELKICH ENERGII

Dnia 15 maja (piątek) o godzinie 10:15, odbędzie się seminarium, na którym zostanie wygłoszony referat pt.:

Do Kaons change their mass inside hot and dense nuclear matter?

Referuje: dr hab. Krzysztof Piasecki (IFD UW)

Abstract:

According to QCD, strong interactions of a hadron with virtual quark-antiquark pairs in the vacuum are the process responsible for the acquisition of most of hadron’s mass from the sum of current quark masses. During the relativistic collision of heavy ions the reverse process should occur, called the partial restoration of chiral symmetry. A hadron in hot and dense nuclear matter should change its basic properties like mass and decay constant with respect to the well known values in vacuum.

Kaons produced in heavy ion collisions around threshold for their production in NN collision appear to be a good probe of these effects.

First comparisons of experimentally found phase space distributions of kaons to the transport model calculations suggested a clear sensitivity to this effect. Meanwhile the theoretical predictions suggested that the mass change should be not only density-dependent, but also momentum-dependent. In the seminar these comparison will be presented.

However, data from collisions around strangeness threshold published recently by HADES and FOPI suggest a much broader and complex landscape. Any extraction of possible changes of K- mass has to account for the downfeed from Phi meson decay. Also, comparisons for K0s and Lambda emitted from Au+Au at 1.2A GeV show that the model description is still not fully consistent.

Serdecznie zapraszamy

dr hab. Katarzyna Grzelak
prof. dr hab. Jan Królikowski
prof. dr hab. Aleksander Filip Żarnecki

The meeting will take place on zoom.us platform.

https://us02web.zoom.us/j/176261850?pwd=cWgzMkwvVjBTSm5ObTFMSnBPTndIQT09

Zoom meeting ID: 176 261 850

## SEMINARIUM FIZYKI WIELKICH ENERGII

SEMINARIUM FIZYKI WIELKICH ENERGII

Dnia 8 maja (piątek) o godzinie 10:15, odbędzie się seminarium, na którym zostanie wygłoszony referat pt.:

ELITPC: toward studying nuclear reactions at astrophysical energies

Referuje: mgr Mateusz Fila (IFD UW)

Abstract:

In the joint effort of several members of the Institute of Experimental Physics at the Faculty of Physics, University of Warsaw an active target TPC with electronic readout – ELITPC – is being developed. The detector is suited for studying nuclear reactions of the astrophysical interest at the stellar relevant energies. I will present the general detector design, used techniques and done developments as well as describe ongoing works and plans for the near future.

Serdecznie zapraszamy

dr hab. Katarzyna Grzelak
prof. dr hab. Jan Królikowski
prof. dr hab. Aleksander Filip Żarnecki

The meeting will take place on zoom.us platform.

Zoom meeting ID: 176 261 850

## SEMINARIUM FIZYKI WIELKICH ENERGII

SEMINARIUM FIZYKI WIELKICH ENERGII

Dnia 24 kwietnia (piątek) o godzinie 10:15, odbędzie się seminarium, na którym zostanie wygłoszony referat pt.:

PolFEL – Polish Free Electron Laser and its research capabilities

Referuje: Paweł Krawczyk (NCBJ)

Abstract:

PolFEL is a new research facility currently under construction at NCBJ at Otwock-Świerk in Poland. The facility will comprise a free electron laser powered by an entirely superconductive accelerator designed for continues wave (cw) and long pulses (lp) operation. Besides the photon beams provided to the experimental end stations, the gain of the accelerator physics and engineering capabilities are a desired benefit of this project.

PolFEL will be furnished with three undulator chains settled in the two accelerator branches. The full energy branch will provide an electron beam with energy up to 155 MeV in cw mode and up to 187 MeV in lp mode that will allow to generate the coherent light with the wavelength down to 55 nm (in the 3rd harmonics). The striving to attain VUV ranged beam in spite of limited electrons energy brings forth the need of a challenging, short period undulator design and impels to minimize an electron beam emittance. The low energy branch will provide the electrons with energies up to 80 MeV in cw. The radiation wavelength will cover two spectral ranges: IR – from 5 µm up to 50 µm and THz – covering the so called “terahertz gap” of 0.3 THz – 5 THz. Photon beamlines capable of providing the photon diagnostic setups and guiding the beams to the experimental stations will be constructed adjoined to the undulator chains. Still another experimental station will employ femtosecond x-ray pulses in the keV range generated in Compton backscattering process employing the accelerated electron beam and photon beam from auxiliary optical laser.

PolFEL is constructed by a Consortium of 8 institutions lead by NCBJ. The project received funding from the European Regional Development Fund in the framework of the Smart Growth Operational Programme, Measure 4.2: Development of modern research infrastructure of the science sector and, noticeably, a support from the Industry.

Serdecznie zapraszamy

dr hab. Katarzyna Grzelak
prof. dr hab. Jan Królikowski
prof. dr hab. Aleksander Filip Żarnecki

The meeting will take place on zoom.us platform.

Zoom meeting ID: 176 261 850

## SEMINARIUM FIZYKI WIELKICH ENERGII

SEMINARIUM FIZYKI WIELKICH ENERGII

Dnia 17 kwietnia (piątek) o godzinie 10:15, odbędzie się seminarium, na którym zostanie wygłoszony referat pt.:

Machine Learning event identification in H → ττ analysis of CMS

Referuje: Michał Olszewski

Abstract:

The H → τ+τ− channel (branching fraction about 6%) is currently one of two (next to H → bb̄ with branching fraction of about 57%) at the LHC best suited to perform measurements of 125 GeV Higgs boson couplings to fermions. The first observation of this process in a single experiment was achieved by the CMS Collaboration and published in 2017. The analysis summarized in the publication is driven by several characteristics specific for aforementioned Higgs boson decay mode. First, the tau lepton cannot by directly observed at the detector due to short lifetime. Second, it decays either leptonically or semi-leptonically due to invariant mass larger than mass of the lightest mesons. Furthermore, the large QCD background at LHC and presence of the neutrinos in the final state enforces usage of sophisticated algorithms for tau identification and ditau system mass reconstruction (respectively). In the first part of the talk I’ll shortly present how CMS analysis deals with above topics. In the second part I’ll show how machine learning techniques can by used to reinforce the analysis sensitivity to the signal.

Spotkanie odbędzie się za pośrednictwem platformy zoom:

Zoom meeting ID: 176 261 850

## SEMINARIUM FIZYKI WIELKICH ENERGII

SEMINARIUM FIZYKI WIELKICH ENERGII

Dnia 3 kwietnia (piątek) o godzinie 10:15, odbędzie się seminarium, na którym zostanie wygłoszony referat pt.:

Probing CP structure of the Higgs boson couplings with the CMS experiemnt

Referuje: Michał Bluj (NCBJ)

Violation of the CP symmetry is one of the Sakharov conditions required to explain the baryon asymmetry observed in Universe. Although the CP violation is already built in the Standard Model via quark mixing, its strength is not sufficient to explain the magnitude of the observed baryon asymmetry. This motivates searches for new sources of CP violation in the Higgs sector. In this seminar recent results of studies on the CP structure of the Higgs boson coupligs with the CMS experiment will be discussed.

Serdecznie zapraszamy

dr hab. Katarzyna Grzelak
prof. dr hab. Jan Królikowski
prof. dr hab. Aleksander Filip Żarnecki

The meeting will take place on zoom.us platform.

Zoom meeting ID: 176 261 850

## SEMINARIUM FIZYKI WIELKICH ENERGII

SEMINARIUM FIZYKI WIELKICH ENERGII

Dnia 6 marca (piątek) o godzinie 10:15, w sali B2.38 odbędzie się seminarium, na którym zostanie wygłoszony referat pt.:

Current state of observations from LIGO-Virgo detectors and O3 science run

The aim of a talk is to give an overview current state gravitational wave observations. During three science runs (2015-2016, 2016-2017, 2019-2020) of Advanced LIGO-Virgo detectors multiple binary merger events were observed. Most of the events are binary black hole mergers, but nine detected events had neutron star component. Those observations, especially GW170817, brought additional way to study neutron stars.

Serdecznie zapraszamy

dr hab. Katarzyna Grzelak
prof. dr hab. Jan Królikowski
prof. dr hab. Aleksander Filip Żarnecki

Videoconference Room:  https://indico.cern.ch/event/895122/

## SEMINARIUM FIZYKI WIELKICH ENERGII

SEMINARIUM FIZYKI WIELKICH ENERGII

Dnia 28 lutego (piatek) o godzinie 10:15, w sali B2.38 odbedzie sie seminarium, na ktorym zostanie wygloszony referat pt.:

Plasma wakefield accelerators. EuPRAXIA and ALEGRO projects

Referuje: prof. Roman Walczak (University of Oxford)

After brief introduction to plasma wakefield accelerators, I will present the conceptual design of a new European research infrastructure, EuPRAXIA. The concept has been establish over last 4 years in a collaboration of 30 institutes in Europe and 11 laboratories in Asia, Russia and the United States. EuPRAXIA is the first European project that develops a dedicated particle accelerator research infrastructure based on novel plasma concepts and laser technology. I will also present ALEGRO project, which considers long-term prospect of applying novel accelerators at the high-energy frontier of particle physics.

Serdecznie zapraszamy

dr hab. Katarzyna Grzelak
prof. dr hab. Jan Królikowski
prof. dr hab. Aleksander Filip Żarnecki

Videoconference Room:   https://indico.cern.ch/event/892311/

## SEMINARIUM FIZYKI WIELKICH ENERGII

SEMINARIUM FIZYKI WIELKICH ENERGII

Dnia 24 stycznia (piatek) o godzinie 10:15, w sali B2.38 odbedzie sie seminarium, na ktorym zostanie wygloszony referat pt.:

The LUXE – Laser und XFEL Experiment – era of strong fields QED.

Referuje: dr hab. Grzegorz Grzelak (IFD UW)

The seminar will introduce LUXE, „Laser Und XFEL Experiment”, currently being developed at DESY in Hamburg, an experiment that aims to use the high-quality electron beam of the European XFEL and a high-power laser.

The scientific goal of the experiment is to study quantum electrodynamics in the largely unexplored territory, in the regime of strong fields, close to and beyond the Schwinger limit, revealing the non-perturbative face of QED.

In the seminar the scientific case of the experiment will be presented.

In particular the details of the nonlinear Compton scattering and nonlinear Breit-Wheeler pair production.

The second part will cover the experimental setup of beam extraction from the European XFEL Linac, the requirements for a powerful laser and precise detectors optimized to measure electrons, positrons and photons.

Serdecznie zapraszamy

dr hab. Katarzyna Grzelak
prof. dr hab. Jan Krolikowski
prof. dr hab. Aleksander Filip Zarneck

Videoconference Room: https://indico.cern.ch/event/882870/