Category: Uncategorized

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 link:  https://zoom.us/j/176261850

Zoom meeting ID: 176 261 850

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 link: https://zoom.us/j/176261850

Zoom meeting ID: 176 261 850

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

Referuje: dr Adam Zadrożny (University of Texas)

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

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

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/

Dnia 17 stycznia (piatek) o godzinie 10:15, w sali B2.38 odbedzie sie seminarium, na ktorym zostanie wygloszony referat pt.:

CP violation in the neutrino sector: Recent long-baseline experiments results

Referuje: mgr Grzegorz Żarnecki (NCBJ)

The violation of CP symmetry in the neutrino sector may be manifested in different oscillation probabilities for neutrinos and antineutrinos. Long-baseline neutrino experiments search for this effect by studying electron (anti)neutrino appearance in primordial muon (anti)neutrino beam. In this talk T2K and NOvA experiments will be presented and their recent results on CP violation will be shown. Future experiments – DUNE and Hyper-Kamiokande – will also be discussed.

Serdecznie zapraszamy

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

Videoconference Room:  https://indico.cern.ch/event/878696/

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

Upgrade of the NA61/SHINE experiment

Referuje: mgr Piotr Podlaski (IFD)

NA61/SHINE is a fixed target experiment located in the North Area of the CERN SPS accelerator. The main goal of the NA61/SHINE after Long Shutdown 2 at CERN (LS2, 2019-2021) is to measure open charm production in Pb+Pb interactions at SPS energies. To accomplish this, NA61/SHINE detection system undergoes a major hardware upgrade. The main purpose of the upgrade is to increase the readout rate up to 1 kHz and increase acceptance in the high density tracks environment. In this seminar I will discuss physics prospects for NA61/SHINE beyond LS2, I will also present status and plans of the upgrade.

Serdecznie zapraszamy

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

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