Month: Kwiecień 2021

SEMINARIUM FIZYKI WIELKICH ENERGII

Dnia 30 kwietnia (piątek) o godzinie 10:15, odbędzie się seminarium pt.:

Warsaw contributions to the 2021 International Workshop on Future Linear Colliders, LCWS2021 (part 2)

Referują:

Krzysztof Mękała: „Heavy Neutrinos at Future Linear e+e- Colliders”

With the Standard Model being unable to describe the observed baryon asymmetry or dark matter density in the universe, many models of the New Physics introduce heavy neutrino species as a possible explanation for these effects. Dirac or Majorana neutrinos with masses above the EW scale could be produced at future linear e+e- colliders, like the Compact LInear Collider (CLIC) or the International Linear Collider (ILC).

We studied the possibility of observing production and decays of heavy neutrinos in qql final state at the ILC running at 500 GeV and 1 TeV, and the CLIC running at 3 TeV. The analysis is based on the WHIZARD event generation and fast simulation of the detector response with DELPHES. Dirac and Majorana neutrinos with masses from 200 GeV to 3.2 TeV are considered. Estimated limits on the production cross sections and on the neutrino-lepton coupling are compared with the current limits coming from the LHC running at 13 TeV, as well as the expected future limits from hadron colliders.

 

Jan Klamka: „Search for the pair-production of charged IDM scalars at high energy CLIC”

Compact Linear Collider is the next energy frontier e+e- collider proposed at CERN. Its goal is to precisely test Standard Model (SM) predictions, as well as directly search for the „new physics”. One of the models predicting such phenomena is the Inert Doublet Model (IDM), a very simple extension of the SM scalar sector. It brings in four new particles, including one good dark matter candidate. CLIC sensitivity for discovery of the IDM scalars has been tested, considering 23 benchmark points in the model parameter space. Both fast and full detector simulation techniques were used, where Delphes model of the CLIC detector was extended to include background from gamma-gamma interactions, essential in this analysis. Study shows that IDM particles can be discovered at CLIC for most of considered benchmark points, with high statistical significance.

 

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.

Join Zoom Meeting

https://us02web.zoom.us/j/84516096743?pwd=a3BYQ24zY1ZjQTF4eFIwUnM2WlNaZz09

Meeting ID: 845 1609 6743

Passcode: HEP_UW

SEMINARIUM FIZYKI WIELKICH ENERGII

Dnia 23 kwietnia (piątek) o godzinie 10:15, odbędzie się seminarium, na którym zostanie wygłoszony referat pt.:

„Test of Lepton Flavour Universality at LHCb”

Referuje: dr. Wojciech Krzemień  (NCBJ)

The Standard Model of particle physics assumes that the interactions of the three charged leptons differ only because of their mass differences. Any deviation from this Lepton Universality Principle would suggest new kind of interactions or particles beyond the Standard Model.

Precision tests of lepton universality have been performed over the years by many experiments.

The recent studies of the LHCb experiment indicate evidence for the breaking of lepton universality in beauty-quark decays, with a statistical significance of 3.1 standard deviations.

In the talk the last results from the LHCb will be discussed in the context of previous and future measurements.

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.

Join Zoom Meeting

https://us02web.zoom.us/j/84516096743?pwd=a3BYQ24zY1ZjQTF4eFIwUnM2WlNaZz09

Meeting ID: 845 1609 6743

Passcode: HEP_UW

SEMINARIUM FIZYKI WIELKICH ENERGII

 

Dnia 16 kwietnia (piątek) o godzinie 10:15, odbędzie się seminarium pt.:

Warsaw contributions to the 2021 International Workshop on Future Linear Colliders, LCWS2021 (part 1)

Referują:

Krzysztof Mękała:  “CLIC sensitivity to invisible scalar decays”

The Compact LInear Collider (CLIC) is a proposed TeV-scale high-luminosity electron-positron collider at CERN. CLIC will allow us to study the Higgs boson properties with very high precision. These measurements can also result in direct or indirect discovery of „new physics”, Beyond the Standard Model (BSM) phenomena, which could help us to understand the nature of dark matter (DM). SM-like Higgs boson or new heavy scalar decays with emission of invisible DM particles can be the only way to observe „new physics” effects at achievable energy scales and establish connection between Standard Model and BSM sectors.

We studied the possibility of measuring invisible Higgs boson and additional heavy scalars decays with experiment at CLIC running at 380 GeV and 1.5 TeV. We estimated the expected limits on the invisible decays of the

125 GeV Higgs boson, as well as the cross section limits for production of an additional neutral Higgs scalar, assuming its invisible decays, as a function of its mass.

 

Kacper Nowak: ”Optimising top-quark threshold scan at e+e- colliders using genetic algorithm”

One of the important goals at the future e+e- colliders is to measure the top-quark mass and width in a scan of the pair production threshold.

However, the shape of the pair-production cross section at the threshold depends also on other model parameters, as the top Yukawa coupling, and the measurement is a subject to many systematic uncertainties.

Presented is the most general approach to the top-quark mass determination from the threshold scan at CLIC, with all relevant model parameters and selected systematic uncertainties and constraints from other measurements included in the fit procedure. The top-quark mass can be extracted with precision of the order of 30 to 40 MeV already for 100 fb-1 of data collected at the threshold. Additional improvement is possible if the running scenario is optimized: with the optimisation procedure based on the genetic algorithm the uncertainty can be reduced by about 25%.

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.

Join Zoom Meeting

https://us02web.zoom.us/j/84516096743?pwd=a3BYQ24zY1ZjQTF4eFIwUnM2WlNaZz09

Meeting ID: 845 1609 6743

Passcode: HEP_UW

SEMINARIUM FIZYKI WIELKICH ENERGII

Dnia 9 kwietnia (piątek) o godzinie 10:15, odbędzie się seminarium, na którym zostanie wygłoszony referat pt.:

„The NICA Complex and the MPD Detector at JINR: status and physics potential”

Referuje: prof. Adam Kisiel (PW)

The Multi-Purpose Detector is under construction at the Joint Institute for Nuclear Research in Dubna, as part of the NICA Accelerator Complex. The MPD Collaboration aims to study the phase diagram of QCD matter at maximum baryonic density, determine the nature of the phase transition between the deconfined and hadronic matter and search for the critical point. The combination of significant luminosity at NICA, collider geometry of the experiment and collision energies for multiple beam species spanning the range of

4 to 11 AGeV, where the transition from baryon to meson dominated matter is expected will allow MPD to provide unique insight into these questions. Progress in the construction on the NICA Complex components will be shown. The status of the assembly of the detector in MPD Hall, as well as the progress in the production of MPD subdetectors will be reported on as well. The initial running plan for NICA will be given.

The design physics performance of the detector will be discussed, with emphasis on main observables relevant for phase diagram study. Tracking and particle identification procedures will enable precise determination of spectra of identified hadrons, including hyperons and hypernuclei, with the aim of multi-differential measurements and total yield extraction. Selected methods of centrality and reaction plane orientation extraction will be compared. The quality of directed and elliptic flow determination will be discussed, with comparison to model expectations. The sensitivity of event-by-event fluctuations to the nature of the phase transition and the presence of a critical point will be given. The femtoscopic analysis for charged pions and kaons has shown sensitivity to first order and cross-over phase transitions in EoS seen for the vHLLE model. All those studies will be put in context of addressing outstanding questions on the properties of the region of the QCD phase diagram probed by heavy-ion collisions in the NICA energy range.

 

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.

Join Zoom Meeting

https://us02web.zoom.us/j/84516096743?pwd=a3BYQ24zY1ZjQTF4eFIwUnM2WlNaZz09

Meeting ID: 845 1609 6743

Passcode: HEP_UW