Zakład Cząstek i Oddziaływań Fundamentalnych

SEMINARIUM FIZYKI WIELKICH ENERGII

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

„Second ECFA Workshop on e+e– Higgs/Electroweak/Top Factories”

Referuje: prof. dr hab. Aleksander Filip Żarnecki (IFD UW)

Second ECFA Workshop on physics and detectors for future e+e– Higgs/Electroweak/Top Factories took place two weeks ago in Paestum, Italy. I will report on the mandate, recent activities and plans of the ECFA study. In particular, I will present the so called Focus Topics, which were proposed to stimulate new activities in the field, covering both theory and experiment, analysis and algorithm development, as well as detector requirements and design optimisation. Selected results presented at the workshop will be discussed.

Serdecznie zapraszamy

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

SEMINARIUM FIZYKI WIELKICH ENERGII

Dnia 20 października (piątek) o godzinie 10:15, w sali B2.38 odbędzie się seminarium, na którym zostanie wygłoszony referat pt.:

„Physics at a muon collider”

Referuje: mgr Krzysztof Mękała (IFD UW)

Among future collider proposals, the idea of building a muon collider has recently been getting more and more attention. As a concept combining the advantages of electron-positron and hadron machines, a muon collider is an ideal candidate for the future large-scale project for particle physics.

Nevertheless, for a long time, the completion of the project has been perceived as being technically unattainable due to the finite lifetime of a muon. However, in recent reports, no insurmountable technological issues have been identified and vivid discussion of the physics potential of such a machine has restarted. In my talk, I will outline the technical concept, demonstrating why the machine seems to be so appealing despite several outstanding technological challenges and I will explain what kind of new physics could be measured at a multi-TeV muon collider.

Serdecznie zapraszamy

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

SEMINARIUM FIZYKI WIELKICH ENERGII

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

„DNA damage and repair in cells exposed to high and low LET”

Referuje: dr hab. Beata Brzozowska (IFD UW)

The DNA damage response to different radiation qualities reflects their mode of action. Cells exposed to densely ionising high and scattered low linear energy transfer (LET) radiation react more strongly than to the same dose of each separately. The relationship between DNA double strand break location inside the nucleus and chromatin structure was evaluated using high-resolution transmission electron microscopy in breast cancer cells and will be presented together with fluorescence microscopic data.

Serdecznie zapraszamy

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

SEMINARIUM FIZYKI WIELKICH ENERGII

Dnia 16 czerwca (piątek) o godzinie 10:15, w sali B2.38 odbędzie się seminarium, na którym zostanie wygłoszony referat pt.:

„Analysing Ultra High Energy Cosmic Ray Air Showers with GRANDProto300”

Referuje: dr Pragati Mitra (IFD UW)

Detecting Ultra High Energy Cosmic Rays (UHECR) and Neutrinos through radio detection is a mature technique that offers a promising avenue for highly inclined air showers. The GRANDProto300 (GP300) array is a pathfinder for the Giant Radio Array for Neutrino Detection (GRAND) project, which will be deployed at a remote mountain site in the Gobi desert, China. Serving as a test bench, the GP300 array is expected to pioneer techniques of autonomous radio detection including identification and reconstruction of nearly horizontal cosmic-ray air showers and shed light on understanding the ‚transition region’ from the galactic to extragalactic cosmic-ray sources. In this seminar, we will explore the prospects of studying air shower parameters with radio technique, then look into the ongoing analysis efforts including offline signal identification and shower reconstruction.

Serdecznie zapraszamy

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

SEMINARIUM FIZYKI WIELKICH ENERGII

Dnia 2 czerwca (piątek) o godzinie 10:15, w sali B2.38 odbędzie się seminarium, na którym zostanie wygłoszony referat pt.:

„Tau neutrinos. What do we know? What can we learn from them?”

Referuje: dr hab. Katarzyna Grzelak (IFD UW)

Tau neutrinos are the least studied leptons. Due to difficulty in distinguishing tau neutrinos from other neutrino flavours, low cross-section and high threshold energy for charged-current interactions only 19 tau neutrino candidates have been event-by-event selected to date.

In the seminar the current status of tau neutrino-related physics, new experiments and new ideas to improve our knowledge of lepton sector will be presented.

Serdecznie zapraszamy

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

SEMINARIUM FIZYKI WIELKICH ENERG

Dnia 26 maja (piątek) o godzinie 10:15, w sali B2.38 odbędzie się seminarium, na którym zostanie wygłoszony referat pt.:

„Gravitational wave astrophysics at the beginning of O4”

Referuje: prof. dr hab. Tomasz Bulik (OA UW)

Abstract

The O4 observational run is starting now. I will review the current
detections and their significance for astronomy and fundamental physics.
As the bulk of detections are binary black holes I will describe the
currently considered models of their formation and compare
the predictions of these models with the data.
Finally I will talk about hopes for the O4 run

.

Serdecznie zapraszamy

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

SEMINARIUM FIZYKI WIELKICH ENERGII

Dnia 19 maja (piątek) o godzinie 10:15, w sali B2.38 odbędzie się seminarium, na którym zostanie wygłoszony referat pt.:

„Towards identifying the sources of Ultra-High Energy Cosmic Rays with the GRAND experiment”

Referuje: dr Lech Wiktor Piotrowski (IFD)

Even though the first UHECR was detected almost 60 years ago, the origin of these particles remains a mystery. For lower energies, their paths are twisted by the Galactic magnetic field, while for higher energies their fluxes are extremely low. That makes identifying the sources unreachable even for the largest existing observatories, that occupy hundreds to thousands of square kilometres.

The problem of the low flux can be solved with building observatories that observe orders of magnitude larger volume of the atmosphere than the current ones. In addition, looking not directly at UHECR, but at neutrinos generated by them close to the source, can eliminate the influence of cosmic magnetic fields. These two ideas will be incorporated into the Giant Radio Array for Neutrino Detection (GRAND) – a future experiment to detect Earth-skimming neutrinos with huge arrays of cheap radio antennas.

The contents of the seminar will include the idea behind the radio detection of UHE CRs and neutrinos, current status of GRAND prototypes, the role of the Polish group and the experimental challenges that we are facing.

Serdecznie zapraszamy

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

SEMINARIUM FIZYKI WIELKICH ENERGII

Dnia 28 kwietnia (piątek) o godzinie 10:15, odbędzie się seminarium online, na którym zostanie wygłoszony referat pt.:

„Study of neutrino mass ordering with the atmospheric neutrinos at Super-Kamiokande”

Referuje: dr Magdalena Posiadała-Zezula (IFD)

Super-Kamiokande (Super-K) is the world’s largest underground water Cherenkov detector which has been studying the atmospheric neutrino oscillations since 1996. Atmospheric neutrinos are famous for covering a wide energy range, have both neutrinos and antineutrinos, with electron and muon flavours, which oscillate to tau neutrinos and are sensitive for matter effects in the earth. Analysis of the atmospheric neutrino data from all five run periods of Super-K running with ultra-pure water, years 1996 – 2020, will be presented. The fiducial volume region has been expanded from 22,5 kton to 27,2 kton, which allowed us to use also the events with reconstructed vertex at least 1~m from the nearest wall of the detector. Additional studies have been performed by adding information from T2K published binned data muon neutrino disappearance and electron appearance. Over the range of parameters allowed at 90% confidence level, the normal mass ordering for neutrinos  is favoured based on the combined results from Super-K and with T2K results.

Serdecznie zapraszamy

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

SEMINARIUM FIZYKI WIELKICH ENERGII

Dnia 21 kwietnia (piątek) o godzinie 10:15, w sali B2.38 odbędzie się seminarium, na którym zostanie wygłoszony referat pt.:

„Strange phase in beautiful oscillation: Measurement of weak phase  in the neutral bottom meson decay”

Referuje: dr Alibordi Muhammad (IFD)

The smallest deviation from the precise value of the CP-violating weak phase predicted by Standard Model  in the B_s to Jpsiphi decay mode would hint for a new domain of physics. Also improving precision with higher statistics of the Run-II proton-proton collision data collected by CMS detector may help to constrain the future theories. These were the motivations of measuring the weak phase in the B_s to Jpsiphi decay.

In this talk we will see how the weak phase measurement is done with ~97fb^-1 of the 13TeV proton-proton collision data and what level of precision is achieved.

Serdecznie zapraszamy

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

SEMINARIUM FIZYKI WIELKICH ENERGII

Dnia 31 marca (piątek) o godzinie 10:15, w sali B2.38 odbędzie się seminarium, na którym zostanie wygłoszony referat pt.:

„Measurements of CP-violating asymmetries in charm decays in the charmingly-beauty experiment – LHCb”

Referuje: dr hab. Artur Ukleja (NCBJ), prof. AGH

mgr Jakub Ryżka (AGH)

One the main goal of High Energy Physics is a search for physics beyond the Standard Model (called new physics). The measurements of CP-violating asymmetries in particle decays containing a charm quark create perfect environment for the new physics searches since the background from the Standard Model is small as the expected value of CP violation is about a few per milles or less. It is significantly smaller then observed in beauty sector. The LHCb experiment tests the Standard Model predictions in very precise measurements of CP violation using very sophisticated research methods. For example, finding disagreement between measured and predicted values will be indirect indication of the existence of new physics.

So far, in the charm sector, CP violation is confirmed as a nonzero difference between two CP-violating asymmetries in D^0 to K^- K^+ and D^0 to pi^- pi^+ decays. This result obtained in 2019 only raised the question of whether the observed difference reflects the CP violation in the D0 meson decays into a pair of kaons, into a pair of pions, or both. Possible interpretations will be discussed during the seminar. Recently, the LHCb experiment has measured the direct CP asymmetries separately for the two decay modes: D^0 to K^- K^+ and D^0 to pi^- pi^+. These results will be presented during the seminar as them constitute the first evidence for CP violation in a specific charm hadron decay. The compatibility with the hypothesis of CP symmetry is 3.8 standard deviations.

The new searches for CP asymmetries in three-body charm baryon decays will be also presented. Three-body processes are always more rare than the two-body processes, but they can provide much more information about CP violation. Many observables are available to measure in multi-body processes. In contrast, in two-body processes, only one variable is measured (global result of CP violation). So far, in charm baryons the level of 2.7 standard deviations of agreement with CP symmetry was measured. The new approaches will be discussed during seminar as well as their tests obtaining in control decays.

Serdecznie zapraszamy

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