This page is always under development ! And not always up to date :-)

Ta strona poswiecona jest mojej dzialalnosci naukowej
Dzialalnosc dydaktyczna omowiona jest na osobnej stronie

See also my dedicated public talks and presentations page.

What I am working on...

Current activities

  • Top physics at future e+e- colliders,

  • Pi of the Sky project,

  • Contact Interaction analysis of the combined HERA data (H1+ZEUS).
    •  See also completed activities below.

    Top physics at future e+e- colliders

    Top quark is a very special particle. It is the heaviest elementary particle we were able to find so far (!). Although it was discovered 20 years ago, we still do not know everything about its properties. Top quarks will be copiously produced at LHC and we hope for precise measurements of its properties there. However, some measurement can be very difficult at LHC, due to high background levels in proton-proton collisions. Much "cleaner" conditions for top studies are expected at future linear e+e- colliders ILC and CLIC, which can also produce very large top samples. In particular, these colliders offer the possibility to measure the top pair production at the threshold, allowing for very precise top quark mass determination with very small theoretical uncertainties.

    I work on estimating the sensitivity of experiments at future high energy e+e- colliders to possible signatures of physics beyond the Standard Model in the top quark sector. Large samples of produced tt pairs and clean environment of lepton collider should allow searching for rare top decays. Flavour Changing Neutral Current (FCNC) decays of the top quark are of particular interest as different extensions of the Standard Model predict significant enhancement of these channels, with branching ratios reaching even 10-2.

    I presented first results of my study, based on the parton level simulation with WHIZARD, at Workshop on Top physics at Lepton Colliders in Valencia, in July 2015: Sensitivity to top FCNC decay t->ch at future e+e- colliders.

    See also a seminar Searching for top FCNC decay t->ch at future e+e- colliders given at our Faculty in June 2015.

    Pi of the Sky project

    This section is being rebuilt now

    Contact Interaction analysis of HERA combined data

    In 2015 the H1 and ZEUS experiments at HERA presented the final results of inclusive deep inelastic cross section combination in neutral and charged current ep scattering. Results are based on the full data sample collected in 1994-2007, corresponding to a luminosity of about 1 fb-1. The measurement was used as an input to QCD analyses, providing a set of parton distribution functions HERAPDF2.0. High precision of the data make also searches for possible signals from Beyond Standard Model, BSM, processes possible.

    I participate in the developement of a new approach to BSM searches, based on the combined analysis of the inclusive ep data, taking into account possible contributions from the ``new physics'' processes in the QCD fit. First limits were set on a radius of quarks, within the semi-classical quark form factor model.

  • Preliminary results based on combined data analysis were submitted to EPS HEP'2015

    • Completed activities

  • Participation in the GLORIA FP7 project, 2011-2014.
  • Member of Restricted ECFA (European Committee for Future Colliders), 2009-2014.
  • Update of the European Strategy for Particle Physics, 2011-2013.
  • Contact Interaction analysis of ZEUS 1994-2007 data,
  • Construction of the EUDET pixel telescope,
  • Photon Collider beam simulation with CAIN.
  • Higgs production at the Photon Collider,
  • CompAZ: parametrization of the energy spectra for gamma-gamma collider at TESLA (dedicated page),
  • Contact Interaction analysis of ZEUS 1994-2000 data,
  • New physics at THERA,
  • Leptoquark searches at TESLA,
  • Leptoquark searches at future experiments,
  • Global leptoquark analysis,
  • Global eeqq contact interaction analysis,
  • Old high Q2 and exotic searches at ZEUS.

    • Participation in the GLORIA project

    GLORIA ("GLObal Robotic-telescopes Intelligent Array") is the first free and open- access network of robotic telescopes in the world. Using Web 2.0 environment can do research in astronomy by observing with robotic telescopes, and/or by analysing data that other users have acquired with GLORIA, or from other free access databases. The network was funded by European Union as a three year FP7 project 2011-2014. Twelve institutions belonging to seven countries were involved, from Spain, Chile, Czech Republic, Ireland, Italy, Poland and Russia. The project made thirteen telescopes available to users: five in Spain, three in Chile, one in Argentina, two in the Czech Republic, one in South Africa and one in Russia.

    I was responsible for development of the LUIZA framework for efficient analysis of astronomical images.

    See also local GLORIA page (in Polish).

    European Committee for Future Colliders

    The     European Committee for Future Accelerators (ECFA) was set up at the beginning of 1963 on the initiative of Prof. Weisskopf, then Director-General of CERN and of Prof. Powell, Chair of the CERN Scientific Policy Committee. ECFA consists of Plenary ECFA, Restricted ECFA, Chair and Secretary and permanent or ad hoc working groups. Restricted ECFA (RECFA) is composed of one member per country, appointed for at most two three-year periods. Restricted ECFA assists and advises the Chair and the Secretary in the current running of ECFA, and acts as the communication channel to each participating country, its physics community and national institutes and authorities. On of the main activities of RECFA is also to monitor the development of particle physics in the CERN member countries through regular visits.

    In 2009-2014 I served two 3-year terms as a representative of the Polish High Energy Community in the Restricted ECFA. I took part in about 20 RECFA visits to most of the CERN member states and major accelerator laboratories.

    I participated in organization of the RECFA visit to Poland in May 2012. I gave an introductory overview talk on the Education and Particle Physics research in Poland.

    European Strategy for Particle Physics

    In 2011-2013 I was a member of the European Strategy Preparatory Group, nominated by ECFA.

    Preparatory Group was responsible for collecting submissions from community, organization of the Open Symposium in Cracow (September 2012), preparation of the report summarizing the status and prospects of the field (so called Physics Briefing Book) and other documents for an Update of the medium and long-term European Strategy for Particle Physics. I was responsible for compilation of the Strong Interaction Physics chapter of the Physics Briefing Book.

    I participated in the Strategy Group meeting in Erice, Italy (January 2013), where the final draft of the Strategy Update was prepared. The document was finally approved by the CERN Council in May 2013.

    I also participated in the preparation of the Polish Particle and Astroparicle Physics Roadmap, submitted as the contribution to the Strategy Update.

    Contact Interaction analysis of ZEUS 1994-2007 data

    Data on high-Q2 neutral current deep inelastic scattering collected by the ZEUS detector at HERA can be used to search for physics beyond the Standard Model. I was responsible for the Contact Interaction (CI) analysis of complete ZEUS data sample: scattering of polarized electrons and positrons from HERA II running (2002-2007) as well as electron and positron data from HERA I (1994-2000). No significant deviations from the Standard Model predictions were observed. I derived limits on the effective mass scale in eeqq contact interactions, on the mass to the Yukawa coupling ratio for heavy-leptoquark models, on the effective Planck-mass scale in models with large extra dimensions and on the quark charge radius.
  • Preliminary results based on 1994-2005 data were submitted to ICHEP'2006.
  • Preliminary results based on 1994-2006 data were submitted to LP'2007.
  • Preliminary results based on final 1994-2007 sample were submitted to EPS'2009.
    • More details can be found on the CI analysis page (ZEUS members only)

    EUDET pixel telescope
  • A.F.Zarnecki, P.Niezurawski,
    EUDET Telescope Geometry and Resolution Studies
    EUDET-Report-2007-01,     [physics/0703058]
    • For more results see also: public talks and presentations.

    Photon Collider beam simulation with CAIN

    For more results see also:     public talks and presentations.

    Higgs studies at Photon Collider

    Production of the Higgs boson at the Photon Collider at ILC is studied for the SM and MSSM Higgs bosons. For light SM higgs and MSSM higgs decay to b-quarks is considered. For heavy SM higgs (above 160 GeV) we consider decays to WW and ZZ. Simulation of signal and background processes takes into account higher order corrections, realistic luminosity spectra and detector effects. Expected precision of the higgs two-photon-width measurement is estimated. For heavy SM higgs large interference effects are expected in the WW decay channel. By reconstructing WW and ZZ final states not only the h->gamma+gamma partial width but also the relative phase of the scattering amplitude can be measured. Measurement of the angular distributions for secondary WW and ZZ decays can be used to study CP properties of the Higgs boson.

    Published results:
  • M.Spira, P.Niezurawski, M.Krawczyk, A.F.Zarnecki,
    Heavy neutral MSSM Higgs Bosons at the PLC - a comparison of two analyses
    Proceedings of Linear Collider Workshop (LCWS06), Banagalore, India, 9-13 Mar 2006,     [hep-ph/0612369]

  • E. Accomando et al.
    Workshop on CP Studies and Non-Standard Higgs Physics
    [hep-ph/0608079]

  • P.Niezurawski, A.F.Zarnecki, M.Krawczyk,
    Simulation of the Higgs boson production at LHC, ILC and photon linear collider.
    Proceedings of PLC'2005, Acta Phys.Polon.B37:1173-1179,2006

  • P.Niezurawski, A.F.Zarnecki, M.Krawczyk,
    LHC wedge at the PLC: Observability of gamma gamma ---> A, H ---> b anti-b.
    Proceedings of PLC'2005, Acta Phys.Polon.B37:1187-1191,2006,

  • LHC/LC Study Group
    Physics interplay of the LHC and the ILC.
    Phys.Rept.426:47-358,2006, [hep-ph/0410364]

  • P.Niezurawski, A.F.Zarnecki, M.Krawczyk,
    Determination of the Higgs-boson couplings and H-A mixing in the generalized SM-like Two Higgs Doublet Model
    JHEP 0502:041,2005. [hep-ph/0403138]

  • P.Niezurawski, A.F.Zarnecki, M.Krawczyk,
    Model-Independent Determination of CP Violation from Angular Distributions in Higgs Boson Decays to WW and ZZ at the Photon Collider
    Acta Phys.Polon.B36:833-844,2005. [hep-ph/0410291]

  • P.Niezurawski, A.F.Zarnecki, M.Krawczyk,
    Study of the Higgs boson decays into W+ W- and ZZ at the photon collider.
    JHEP 0211:034,2002. [hep-ph/0207294]

  • P.Niezurawski, A.F.Zarnecki, M.Krawczyk,
    The SM Higgs boson production gamma gamma ---> h ---> b anti-b at the photon collider at TESLA.
    Acta Phys.Polon.B34:177-188,2003. [hep-ph/0208234]

    • For more results see also: public talks and presentations.

    Contact Interaction analysis of ZEUS 1994-2000 data

    Analysis completed.
    ZEUS Collaboration paper "Search for contact interactions, large extra dimensions and finite quark radius in ep collisions at HERA" , DESY-03-218, Phys.Lett. B591 (2004) 23-41     [hep-ex/0401009]

    New physics at THERA

    Results contributed to the     THERA appendix of the TESLA TDR .

    The sensitivity of THERA to different contact interaction models has been studied in detail. For models conserving parity, scales up to about 18 TeV can be probed at THERA, extending considerably beyond the existing bounds. Significant improvement of existing limits is also expected for models with large extra dimensions. Effective Plank mass scales up to about 2.8 TeV can be probed. THERA will be the best machine to study leptoquark properties, for leptoquark masses up to about 1 TeV. It will be sensitive to the leptoquark Yukawa couplings down to ~0.01.

    You can find more details in:

  • Contact Interactions, Large Extra Dimensions and Leptoquarks at THERA , included in THERA Book ,
    published in Acta Physica Polonica B33 (2002) 619.
  • Previous results and talks on Leptoquark searches at future experiments

    • More about physics at THERA:

  • THERA: Electron-Proton Scattering at sqrt(s) ~ 1 TeV Part VI (Appendices),Chapter 2 of the TESLA TDR,
  • THERA web page.

    • Leptoquark Searches at TESLA

    Results contributed to the     TESLA Technical Design Report (TDR).

    Measurement of the Yukawa couplings of the first-generation leptoquarks has been studied for e+e- collisions at TESLA, at sqrt(s)=800 GeV. By combining measurements from different production and decay channels, determination of Yukawa couplings with precision on the few per-cent level is possible. TESLA will be sensitive to very small leptoquark Yukawa couplings not accessible at LHC, down to ~0.05 e. Distinction between left-handed and right-handed Yukawa couplings is feasible even for leptoquark masses very close to the pair-production kinematic limit.

    You can find more details in:

  • Measurement of the leptoquark Yukawa couplings in e+e- collisions at TESLA , e-print hep-ex/0102043; also available as LC Note LC-PHSM-2001-20 .
  • Previous results and talks on Leptoquark searches at future experiments

    • More about e+e- physics at TESLA:

  • Physics at an e+e- Linear Collider, Part III of TESLA Technical Design Report
  • Collection of Linear Collider notes.

    • Leptoquark Searches at Future Colliders

    Leptoquark searches are considered for future experiments at HERA, Tevatron, LHC, TESLA and THERA. Expected exclusion limits from direct leptoquark searches (leptoquark pair production and single leptoquark production) are compared with indirect limits expected from the contact interaction analysis. Strongest limits on the leptoquark masses and couplings are expected from high luminosity LHC data. If the leptoquark signal suggested by the existing data is detected at LHC, with mass below 1 TeV, TESLA will be an ideal place to study leptoquark properties, provided that the leptoquark Yukawa coupling is not too small.

    You can find more details in:

  • Leptoquark Searches at Future Colliders, e-print hep-ph/0006335, contribution #193 to ICHEP-2000.
  • "Leptoquark Searches in TESLA", talk presented at International Workshop on High Energy Photon Colliders, DESY, Hamburg, June 2000 (see also contribution to proceedings ).
  • "Leptoquark Searches in TESLA", talk presented at ECFA/DESY meeting, Padova, Italy, May 2000.
  • "Leptoquarks and Contact Interactions from Global analysis" talk presented on DIS'2000 in Liverpool, April 2000 (see also contribution to proceedings ).

    • Global Leptoquark Analysis

    Using data from HERA, LEP and the Tevatron, as well as from low energy experiments I try to constrain the Yukawa couplings for scalar and vector leptoquarks in the Buchmuller-Ruckl-Wyler effective model. Some leptoquark models are found to describe the existing experimental data much better than the Standard Model. Assuming that a real leptoquark signal is observed, calculated is an allowed region in the lambda-M plane. The leptoquark signal is mostly resulting from the new data on the atomic parity violation in cesium, but is also supported by recent LEP2 measurements, unitarity violation in the CKM matrix and HERA high-Q2 results.

    You can find more details in:

  • "Leptoquark Signal from Global Analysis", talk presented on ICHEP-2000 in Osaka, July 2000 (see also contribution to proceedings ).
  • Leptoquark Signal from Global Analysis, e-print hep-ph/0003271, published in Euro. Phys. J. C 17 (2000) 695, contribution #125 to ICHEP-2000.
  • "Leptoquarks and Contact Interactions from Global analysis" talk presented on DIS'2000 in Liverpool, April 2000 (see also contribution to proceedings ).

    • Global Contact Interaction Analysis

    Using data from HERA, LEP and the Tevatron, as well as from low energy experiments I try to constrain the scale of possible electron-quark contact interactions. For specific models mass scale limits range up to about 18 TeV. Using the contact interaction framework, I extract limits on possible "new physics" effects at HERA, LEP (TESLA) and the Tevatron.

    You can find more details in:

  • "Leptoquarks and Contact Interactions from Global analysis" talk presented on DIS'2000 in Liverpool, April 2000 (see also contribution to proceedings ).
  • "Contact Interactions and Future Prospects for High Energy Physics" talk presented on EPS HEP'99 in Tampere, July 1999 (see also contribution to proceedings ).
  • Seminar presented in March 1999 at Warsaw (updated June 1999 for presentation at Institute of Physics, Bonn University)
  • Global Analysis of eeqq Contact Interactions and Future Prospects for High Energy Physics, e-print hep-ph/9904334, published in Euro. Phys. J. C11 (1999) 3, 539-557.
  • Contact Interactions: Results from ZEUS and a Global Analysis talk presented on DIS'99 Workshop in Zeuten, April 1999 (see also contribution to proceedings , eprint: hep-ph/9905565).

    • Analysis of ZEUS data 1994-97

    I was involved in the measurement of the High-x/High-Q² NC and CC DIS cross-sections, and in the search for the Lepto-quark production and Contact Interactions.

    Have a look at:
  • "High Q² Events in ep Collisions" - talk presented on DIS'97 Workshop in Chicago (see also contribution to proceedings ).
  • Preliminary ZEUS results on high Q² CC DIS presented at Stony Brook Hadron Collider Workshop on June 10th (1994-96 data).
  • Updated ZEUS results on high Q² CC DIS presented at Leptron-Photon '97 (1995-97 data).
  • Contact Interactions: Results from ZEUS and a Global Analysis talk presented on DIS'99 Workshop in Zeuten, April 1999 (see also contribution to proceedings , eprint: hep-ph/9905565).
    • I was also involved in search for diffractive CC DIS events.

    You can have a look at:
  • Diffractive CC DIS contribution to DIS'96 Workshop proceedings.
  • Diffractive CC DIS contribution to Future Physics at HERA proceedings.
  • Study of diffractive CC DIS selection algorithm - M.Sc. Thesis of Jacek Pliszka (in Polish).