Zakład Cząstek i Oddziaływań Fundamentalnych

SEMINARIUM FIZYKI WIELKICH ENERGII

Dnia 24 marca (piątek) o godzinie 10:15, w sali B2.38 odbędzie się seminarium, na którym zostanie wygłoszony referat pt.:

„Searching for dark matter with liquid-argon detectors”

Referuje: dr. Marek Walczak (AstroCeNT / CAMK PAN)

The nature of dark matter remains unknown and its origin is currently one of the most important questions in physics. In particular direct searches for WIMP dark matter particle interactions with ordinary matter are carried out with large detectors located in underground laboratories to suppress the background of cosmic rays. One of the currently most promising detection technologies is based on the use of a large mass of liquid argon or xenon as a target in the detector.

In this talk, I will discuss the status and plans for dark matter searches with detectors based on liquid argon. I will present the currently operating DEAP-3600 experiment (at SNOLAB, Canada) and introduce the DarkSide-20k detector (under construction at the Gran Sasso laboratory, Italy) and in particular the design of its neutron veto.

Serdecznie zapraszamy

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

SEMINARIUM FIZYKI WIELKICH ENERGII

Dnia 17 marca (piątek) o godzinie 10:15, w sali B2.38 odbędzie się seminarium, na którym zostanie wygłoszony referat pt.:

„Theoretical motivations and experimental signals for a second resonance of the Higgs field”

Referuje: prof. Maurizio Consoli, INFN, Sezione di Catania, Italy

Theoretical arguments and lattice simulations suggest that, beside the known resonance of mass m_h= 125 GeV, defined by its quadratic shape, the effective potential of the Higgs field could exhibit a second, much heavier mass scale M_H = 690 +/- 30 GeV associated with the zero-point energy which determines its depth. In spite of its large mass, however, the heavier state would couple to longitudinal W’s with the same typical strength as the low-mass state at 125 GeV and thus represent a relatively narrow resonance mainly produced at LHC by gluon-gluon fusion. After summarizing the general aspects, I will consider 4 samples of LHC data (2 from ATLAS and 2 from CMS) which suggest a new resonance with a combined mass value of 691(10) GeV. Since the considered measurements have a negligible correlation and since, when comparing with a definite theoretical prediction, local excesses are not downgraded by the so called look-elsewhere effect, the cumulated statistical significance is now substantial. The issue of the second resonance could thus definitely be settled by just adding one or two crucial, missing samples of RUN2 data.

Serdecznie zapraszamy

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

SEMINARIUM FIZYKI WIELKICH ENERGII

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

„LHC searches beyond simplified models”

Referuje: dr hab. Krzysztof Rolbiecki (IFT UW)

In this talk I will discuss a concept of simplified models which is used for interpretation of searches for new physics at the LHC. I will discuss limitations of this approach and the need for reinterpretation of results. Then I will introduce several computer programs that are used to reinterpret ATLAS and CMS searches beyond Standard Model physics. Finally I will show recent examples of reinterpretation efforts from the theory community.

Serdecznie zapraszamy

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

SEMINARIUM FIZYKI WIELKICH ENERGII

Dnia 3 marca (piątek) o godzinie 10:15, w sali B2.38 odbędzie się seminarium, na którym zostanie wygłoszony referat pt.:

„Warsaw Active-Target Time Projection Chamber – a powerful tool to study nuclear reactions of astrophysical interests but not only”

Referuje: dr inż. Magdalena Kuich (IFD UW)

Crucial interests in nuclear astrophysics are (p,γ) and (α,γ) reactions. In particular, those that regulate the ratio of C and O and those that burn 18O and, therefore, regulate the ratio between 16O and 18O in the Universe. Such reactions in the stars happen at energies well below the Coulomb barrier and the respective cross-sections are incredibly small, often below the experimental reach. Therefore, the available experimental results on cross-sections for low energies are very sparse, and theoretical extrapolations are burdened with large uncertainties.           

An opportunity to elude a part of the experimental limitations is to study the time-reversal reaction, i.e. photo-disintegration. For this purpose, a novel active-target Time Projection Chamber (TPC) optimised for experiments with high-intensity γ-ray beams was developed and built at the Faculty of Physics, University of Warsaw.

Several experiments with the Warsaw active-target TPC were performed in the summer of 2021 at the IFJ PAN Cracow and in the spring and summer of 2022 at HIgS, TUNL, USA.

Preliminary results of the performed measurements at IFJ and HigS will be presented and an outlook on future experiments will be given.

Serdecznie zapraszamy

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

SEMINARIUM FIZYKI WIELKICH ENERGII

Dnia 7 lutego (wtorek) o godzinie 11:15, w sali B2.38 odbędzie się seminarium, na którym zostanie wygłoszony referat pt.:

„Vector Boson Scattering at the LHC – Precision, Polarization and New Physics Searches”

Referuje: prof. Juergen Reuter (DESY Theory Group, Hamburg)

Abstract:

The scattering of electroweak vector bosons (VBS) is at the heart of electroweak symmetry breaking: it demonstrates the unitarization by the Higgs exchange, which is a subtle cancellation of quadratic energy rise.

This, together with the fact, that VBS covers the multi-TeV energy range make it an ideal tool to search for new physics. In this talk, I will discuss the status of the SM precision calculation, also for polarized VBS. Three types of new physics signal modelling will be

presented: SM effective field theories (SMEFT), simplified models, and specific new physics models important for VBS. Pros and cons of these modellings will be discussed.

Serdecznie zapraszamy

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

SEMINARIUM FIZYKI WIELKICH ENERGII

Dnia 27 stycznia (piątek) o godzinie 10:15, w sali B2.38 odbędzie się seminarium, na którym zostanie wygłoszony referat pt.:

„The LUXE – Laser und XFEL Experiment-towards non-perturbative 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 facility and a high-power optical 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 and going beyond the formalism of linear equations of quantum electrodynamics.

The seminar will also introduce the experimental setup:

beam extraction from the European XFEL Linac, requirements for a high power laser and precise detectors optimized to measure electrons, positrons and photons including contribution to the experiment form the University of Warsaw.

Serdecznie zapraszamy

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

SEMINARIUM FIZYKI WIELKICH ENERGII

Dnia 20 Stycznia (piątek) o godzinie 10:15, w sali B2.38 odbędzie się

seminarium, na którym zostanie wygłoszony referat pt.:

„How to see Dark Matter at LHC?”

Referuje: dr Małgorzata Kazana (NCBJ)

Abstract:

During the seminar, the review of searches for Dark Matter at LHC will be given.

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

SEMINARIUM FIZYKI WIELKICH ENERGII

Dnia 13 Stycznia (piątek) o godzinie 10:15, w sali B2.38 odbędzie się

seminarium, na którym zostanie wygłoszony referat pt.:

„Portrait of the Higgs boson for 10th anniversary of its discovery”

Referuje: : dr hab. Michał Bluj (NCBJ).

Abstract:

A discovery of a Higgs boson was announced by the ATLAS and CMS

experiments 10 years ago. In this talk I will summarise knowledge on its

properties.

Serdecznie zapraszamy

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

SEMINARIUM FIZYKI WIELKICH ENERGII

Dnia 16 Grudnia (piątek) o godzinie 10:15, w sali B2.38 odbędzie się

seminarium, na którym zostanie wygłoszony referat pt.:

„Latest CMS result on top mass”

Referuje: : dr hab. Artur Kalinowski, prof. UW (IFD UW)

Abstract:

I will present a recent measurement of the top quark mass made by the CMS Collaboration. The measurement is the current most precise single top quark measurement. I will finish with some remarks on the importance of the top mass for the vacuum stability.

Serdecznie zapraszamy

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

SEMINARIUM FIZYKI WIELKICH ENERGII

Dnia 2 Grudnia (piątek) o godzinie 10:15, w sali B2.38 odbędzie się

seminarium, na którym zostanie wygłoszony referat pt.:

„New T2K Oscillation Results”

Referuje: Kamil Skwarczyński (NCBJ)

Abstract:

T2K is a long-baseline neutrino oscillation experiment, which studies the oscillations of neutrinos from a beam produced using the J-PARC accelerator chain. The neutrino beam propagates over 295 km before reaching the Super-Kamiokande detector, where they can be detected after having oscillated. The ability of the experiment to run with either neutrino beams or anti-neutrino beam makes it well suited to study the differences between the oscillations of neutrinos, in particular to look for a possible violation of CP symmetry in the lepton sector. T2K has produced a new analysis of its first 10 years of data, with improved models to describe neutrino interactions and fluxes as well as additional samples of near and far detector events. We will present the results of the measurement of the parameters describing neutrino oscillations obtained with the new analysis.

Serdecznie zapraszamy

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