New analysis methods and tests of quantum chromodynamics at the LHC  Page description

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Details of project

  
Identifier
81614
Type K
Principal investigator Siklér, Ferenc
Title in Hungarian Új kiértékelési módszerek kifejlesztése és a kvantumszíndimamika vizsgálata az LHC-n
Title in English New analysis methods and tests of quantum chromodynamics at the LHC
Keywords in Hungarian kiértékelés, QCD, LHC
Keywords in English data analysis, QCD, LHC
Discipline
Physics (Council of Physical Sciences)100 %
Ortelius classification: Physics
Panel Physics 1
Department or equivalent High Energy Physics Department (Wigner Research Centre for Physics)
Participants Hegyi, Sándor
Krajczár, Krisztián
Veres, I. Gábor
Starting date 2010-02-01
Closing date 2014-08-31
Funding (in million HUF) 12.732
FTE (full time equivalent) 11.03
state closed project
Summary in Hungarian
A világ legnagyobb részecskegyorsítója, a Genf melletti Európai Részecskefizikai Laboratóriumban (CERN) felépült Nagy Hadronütköztető (LHC) 2009 őszén kezdi meg működését: protonokat fog eddig soha nem látott energiára felgyorsítani és ütköztetni. A javasolt kutatás két kiegészítő részből áll: új kiértékelési módszerek kifejlesztése és kísérleti nagyenergiás fizika.

Tervezzük egyes jelenleg használt kiértékelési módszer továbbfejlesztését: kis impulzusú töltött részecskék kis tévesztésű nyomkövetése; javított kölcsönhatási pont keresés; beütések paramétereinek jobb meghatározása; energiaveszteség becslésének optimalizálása; részecskeazonosítás nyomkövető detektorokkal; gyors hadronok azonosítása kaloriméterekkel. Ezek a módszerek általánosak, nem kötődnek egy adott kísérleti berendezéshez.

A CMS kísérlet keretében a mért adatok több kezdő analízisének előkészítésében és végrehajtásában vállalunk vezető szerepet, amely a töltött és semleges hadronok számeloszlásánal, spektrumának és korrelációinak meghatározásával, fizikai értelmezésével foglalkozik. Az így kapott adatok alapvetőek a hadron-hadron kölcsönhatások nemperturbatív és perturbatív tulajdonságainak megértéséhez több energián (0.9, 7 és 10 TeV), de fontosak lesznek a nehéz, nagy mérési pontosságot igénylő mérések megalapozására is.
Summary
The largest particle accelerator in the world, the Large Hadron Collider (LHC) was built at the European Organization for Nuclear Research (CERN) in Geneva. It will start to operate in the fall of 2009 by accelerating and colliding protons at energies never seen before. The proposed research is composed of two complementary topics: new analysis methods and experimental high-energy physics.

We plan to substantially improve present analysis methods used in high energy physics, such as low momentum and low fake rate tracking; improved primary vertex finding; advanced estimation of hit cluster parameters; optimized energy loss estimation; particle identification with tracker detectors; identification of fast hadrons with calorimetry. These methods are general, not specific to any given experimental apparatus.

Our group also plays a leading role in the preparations and will carry out many of the first analyses at the CMS experiment. They will deal with the determination and discussion of the multiplicity, spectra and correlations of charged and neutral hadrons. The expected data are essential for the better understanding of both non-perturbative and perturbative aspects of high-energy hadron interactions, at several energies (0.9, 7 and 10 TeV). They will also be important to establish a firm basis for exclusive measurements that require highest precision.




 

Final report

  
Results in Hungarian
A gáztöltésű és a szilícium-alapú detektorok kiértékelésével, a töltött részecskék nyomkövetésével és azonosításával kapcsolatos új módszereket dolgoztunk ki, majd alkalmaztunk. Az proton-proton ütközésekben elért eredményeink hozzájárultak az erős kölcsönhatás folyamatainak leírására vállalkozó modellek javításához. A kapott adatok jó egyezést mutatnak egyszerű elgondolásokkal is (Tsallis-eloszlás, gluontelítés). Az események legfontosabb jellemzőit döntően az ütközésben keltett részecskék száma határozza meg. Az ólom-ólom ütközésekben létrejövő kvark-gluon plazma vizsgálata során azt találtuk, hogy a töltött hadronok keletkezése nagy impulzusnál elnyomódik, ami a keltett partonok közegben leadott energiájáról ad információt. A nehéz mezonok gerjesztett állapotainak fokozatos elnyomása a forró és sűrű közeg hőmérsékletére utal. Az elektrogyenge bozonok keltése ugyanakkor nem módosul. A proton-ólom ütközések segítségével a hideg maganyag hatásait tudtuk tanulmányozni. Az ütközések centralitásának meghatározását különböző módszerekkel végeztük el. A töltött hadronok keltése itt nem mutat elnyomást, de nagy impulzusoknál kis hozamtöbbletet találtunk, amit a jelenlegi nukleáris partoneloszlás-függvények nem tudnak leírni. Az OTKA támogatásával végzett kutatás során született cikkekre eddig 1285 hivatkozás érkezett.
Results in English
We have developed and employed new analysis methods related to the tracking of charged particles and their identification for gas-filled and silicon-based particle detectors. In the study of proton-proton collisions our results contributed to the improvement of models describing the strong interaction processes. The resulted data agree well with the implications of simple theoretical ideas (Tsallis distribution, gluon saturation). The most important characteristics of the observed collisions are primarily determined by the number of produced particles. In the study of the quark-gluon plasma created in lead-lead collisions we have found that the formation of charged hadrons is suppressed at high momenta, which gives information about the energy loss of partons in the created medium. The gradual suppression of the excited mesonic states in this hot and dense matter reveals its temperature. The generation of the electroweak bosons, however, is unchanged. With help of proton-lead collisions we have studied the effects of the cold nuclear matter. We have determined the centrality of the collisions using different methods. The formation of charged hadrons does not show suppression here, but the small surplus found at high momenta cannot be described by the present nuclear parton distribution functions. The publications of this OTKA-supported research were cited 1285 times so far.
Full text https://www.otka-palyazat.hu/download.php?type=zarobeszamolo&projektid=81614
Decision
Yes





 

List of publications

  
Gábor I Veres for the CMS Collaboration: Heavy-ion physics results from CMS, Nuovo Cim. C035 (2012) 115122, 2012
Gábor I Veres for the CMS Collaboration: Overview of results on jets from the CMS Collaboration, Nucl. Phys. A 904-905 (2013) 146c-153c, 2012
Gábor Veres for the ATLAS and CMS Collaborations: Heavy ions: jets and correlations, PoS EPS-HEP2013 (2013) 143, 2013
Gábor I Veres for the ATLAS and CMS Collaborations: Heavy ion results from ATLAS and CMS, Nucl. Phys. Proc. Suppl. 245 (2013) 4548, 2013
Gábor Veres for the CMS Collaboration: Heavy ion physics with the CMS experiment, CMS CR 2013/123, Proceedings of Hadron Structure'13 Conference, 2013
Ferenc Siklér: Particle identification with a track fit χ2, Nucl. Instrum. Meth. A 620 (2010) 477-483, 2010
Ferenc Siklér: Study of clustering methods to improve primary vertex finding for collider detectors, Nucl. Instrum. Meth. A 621 (2010) 526-533, 2010
Krisztián Krajczár for the CMS Collaboration: QCD Physics from CMS, PoS(DIS 2010)117, 2010
Krajczár Krisztián: Az első ütközések az LHC-ban: a CMS Együttműködés eredményei 900 GeV és a világrekord 2.36 TeV ütközési energián, Nukleon 3, 1-6, 2010
Ferenc Siklér for the CMS Collaboration: Highlights from CMS, PoS(DIS 2010)006, 2010
CMS Collaboration: Transverse momentum and pseudorapidity distributions of charged hadrons in pp collisions at sqrt(s) = 0.9 and 2.36 TeV, JHEP 02 (2010) 041, 2010
CMS Collaboration: Transverse momentum and pseudorapidity distributions of charged hadrons in pp collisions at sqrt(s) = 7 TeV, Phys. Rev. Lett. 105 (2010) 022002, 2010
Gábor I Veres for the CMS Collaboration: Inclusive distributions of charged hadrons in pp collisions at sqrt(s) = 0.9 and 2.36 TeV, arXiv:1006.0948 [hep-ex], 2010
CMS Collaboration: Strange Particle Production in pp Collisions at sqrt(s) = 0.9 and 7 TeV, JHEP 05 (2011) 064, 2011
CMS Collaboration: Observation and studies of jet quenching in PbPb collisions at nucleon-nucleon center-of-mass energy = 2.76 TeV, Phys. Rev. C 84 (2011) 024906, 2011
Ferenc Siklér, Sándor Szeles: Optimized estimation of energy loss rate for charged particles from energy deposit measurements in tracking detectors, Nucl. Instrum. Meth. A 687 (2012) 30-39, 2012
Ferenc Siklér: A parametrisation of the energy loss distributions of charged particles and its applications for silicon detectors, Nucl. Instrum. Meth. A 691 (2012) 16-29, 2012
Krisztián Krajczár and the CMS Collaboration: Charged hadron multiplicity and transverse energy densities in PbPb collisions from CMS, J. Phys. G: Nucl. Part. Phys. 38 (2011) 124041, 2011
CMS Collaboration: Dependence on pseudorapidity and centrality of charged hadron production in PbPb collisions at a nucleon-nucleon centre-of-mass energy of 2.76 TeV, JHEP 08 (2011) 141, 2011
Krisztián Krajczár for the CMS Collaboration: Spectra of weakly decaying identified particles at 0.9 and 7 TeV with the CMS detector, EPJ Web of Conferences 13 (2011) 03003, 2011
Ferenc Siklér for the CMS Collaboration: Measurements of hadron production at CMS, EPJ Web of Conferences 13 (2011) 03002, 2011
Ferenc Siklér: Particle identification with a track fit χ2, Nucl. Instrum. Meth. A 639 (2011) 256-259, 2011
C Salgado et al, incl Ferenc Siklér: Proton-Nucleus Collisions at the LHC: Scientific Opportunities and Requirements, J. Phys. G: Nucl. Part. Phys. 39 (2012) 015010, 2012
CMS Collaboration: Study of the inclusive production of charged pions, kaons, and protons in pp collisions at sqrt(s) = 0.9, 2.76, and 7 TeV, Eur. Phys. J. C 72 (2012) 2164, 2012
CMS Collaboration: Measurement of the inelastic proton-proton cross section at √s = 7 TeV, CMS PAS QCD-11-002, 2012
CMS Collaboration: Measurement of the inelastic proton-proton cross section at √s = 7 TeV, arXiv:1210.6718, submitted to Phys. Lett. B, 2012
CMS Collaboration: Observation of sequential Y suppression in PbPb collisions, Phys.Rev.Lett. 109 (2012) 222301, 2012
CMS Collaboration: Z boson production with the 2011 data in PbPb collisions, CMS PAS HIN-12-008, 2012
CMS Collaboration: Study of high-pT charged particle suppression in PbPb compared to pp collisions at √sNN= 2.76 TeV, Eur. Phys. J. C 72 (2012) 1945, 2012
CMS Collaboration: Detailed characterization of jets in heavy ion collisions using jet shapes and jet fragmentation functions, CMS PAS HIN-12-013, 2012
CMS Collaboration: Observation of long-range near-side angular correlations in proton-lead collisions at the LHC, Phys. Lett. B 718 (2013) 795-814, 2013
Krisztián Krajczár for the CMS Collaboration: Measurement of charged particle RAA at high pT in PbPb collisions at √sNN = 2.76 TeV with CMS, arXiv:1208.6218; proceedings of the Hard Probes 2012 conference, 2012
Anna Julia Zsigmond for the CMS Collaboration: Inelastic proton-proton cross section measurements in CMS at √s = 7 TeV, arXiv:1205.3142, proceedings of the DIS 2012 conference, 2012
Ferenc Siklér for the CMS Collaboration: Spectra of Charged Pions, Kaons, and Protons Identified via Tracker Energy Loss from CMS, proceedings of the DIS 2012 conference, 2012
Ferenc Siklér: Particle identification with a track fit χ2, Nucl. Instrum. Meth. A 620 (2010) 477-483, 2010
Ferenc Siklér: Study of clustering methods to improve primary vertex finding for collider detectors, Nucl. Instrum. Meth. A 621 (2010) 526-533, 2010
CMS Collaboration: Transverse momentum and pseudorapidity distributions of charged hadrons in pp collisions at sqrt(s) = 0.9 and 2.36 TeV, JHEP 02 (2010) 041, 2010
CMS Collaboration: Transverse momentum and pseudorapidity distributions of charged hadrons in pp collisions at sqrt(s) = 7 TeV, Phys. Rev. Lett. 105 (2010) 022002, 2010
CMS Collaboration: Strange Particle Production in pp Collisions at sqrt(s) = 0.9 and 7 TeV, JHEP 05 (2011) 064, 2011
CMS Collaboration: Observation and studies of jet quenching in PbPb collisions at nucleon-nucleon center-of-mass energy = 2.76 TeV, Phys. Rev. C 84 (2011) 024906, 2011
Ferenc Siklér, Sándor Szeles: Optimized estimation of energy loss rate for charged particles from energy deposit measurements in tracking detectors, Nucl. Instrum. Meth. A 687 (2012) 30-39, 2012
Ferenc Siklér: A parametrisation of the energy loss distributions of charged particles and its applications for silicon detectors, Nucl. Instrum. Meth. A 691 (2012) 16-29, 2012
Krisztián Krajczár and the CMS Collaboration: Charged hadron multiplicity and transverse energy densities in PbPb collisions from CMS, J. Phys. G: Nucl. Part. Phys. 38 (2011) 124041, 2011
CMS Collaboration: Dependence on pseudorapidity and centrality of charged hadron production in PbPb collisions at a nucleon-nucleon centre-of-mass energy of 2.76 TeV, JHEP 08 (2011) 141, 2011
Ferenc Siklér: Particle identification with a track fit χ2, Nucl. Instrum. Meth. A 639 (2011) 256-259, 2011
C Salgado et al, incl Ferenc Siklér: Proton-Nucleus Collisions at the LHC: Scientific Opportunities and Requirements, J. Phys. G: Nucl. Part. Phys. 39 (2012) 015010, 2012
CMS Collaboration: Study of the inclusive production of charged pions, kaons, and protons in pp collisions at sqrt(s) = 0.9, 2.76, and 7 TeV, Eur. Phys. J. C 72 (2012) 2164, 2012
CMS Collaboration: Measurement of the inelastic proton-proton cross section at √s = 7 TeV, Phys Lett B 722 (2013) 5, 2013
CMS Collaboration: Observation of sequential Y suppression in PbPb collisions, Phys.Rev.Lett. 109 (2012) 222301, 2012
CMS Collaboration: Study of high-pT charged particle suppression in PbPb compared to pp collisions at √sNN= 2.76 TeV, Eur. Phys. J. C 72 (2012) 1945, 2012
CMS Collaboration: Observation of long-range near-side angular correlations in proton-lead collisions at the LHC, Phys. Lett. B 718 (2013) 795-814, 2013
Anna Julia Zsigmond for the CMS Collaboration: Inelastic proton-proton cross section measurements in CMS at √s = 7 TeV, arXiv:1205.3142, proceedings of the DIS 2012 conference, 2012
Ferenc Siklér for the CMS Collaboration: Spectra of Charged Pions, Kaons, and Protons Identified via Tracker Energy Loss from CMS, proceedings of the DIS 2012 conference, 2012
CMS Collaboration: Study of the production of charged pions, kaons, and protons in pPb collisions at sqrt(sNN) = 5.02 TeV, Eur. Phys. J. C 74 (2014) 2847, 2014
Ferenc Siklér for the CMS Collaboration: Identified particles in pPb collisions in CMS, Nucl Phys A 926 (2014) 128-135, 2014
CMS Collaboration: Femtoscopy with identified charged hadrons in pp, pPb, and peripheral PbPb collisions at LHC energies, CMS PAS HIN-14-013, 2014
CMS Collaboration: Studies of dijet transverse momentum balance and pseudorapidity distributions in pPb collisions at 5.02 TeV, Eur. Phys. J C. 74 (2014) 295, 2014
CMS Collaboration: Centrality determination for pPb data 2013, CMS Detector Performace Note, DP-2013-034, 2013
CMS Collaboration: Centrality measurement in pPb collisions, CMS Detector Performace Note, DP-2014-009, 2013
CMS Collaboration: Study of Z boson production in the muon decay channel in pPb collisions at 5.02 TeV, CMS PAS HIN-14-003, 2014
Anna J Zsigmond for the CMS Collaboration: Z and W boson production in pPb collisions with CMS, Nucl. Phys. A, in press, 2014
CMS Collaboration: Z boson production via the electron and muon channels in PbPb collisions at 2.76 TeV, CMS PAS HIN-13-004, 2014
Anna J zsigmond for the CMS Collaboration: Electroweak bosons in CMS, Nucl. Phys. A 926 (2014) 34, 2014
CMS Collaboration: Charged particle nuclear modification factor and pseudorapidity asymmetry in pPb collisions at sqrt(sNN)=5.02 TeV with CMS, http://cds.cern.ch/record/1625865, 2013
Krisztián Krajczár for the CMS Collaboration: Transverse momentum and pseudorapidity dependence of charged particle production and nuclear modification factor in proton–lead collisions at sqrt(sNN)=5.02 TeV with CMS, Nucl Phys A, in press, 2014
Krisztián Krajczár for the CMS Collaboration: Measurement of charged particle RAA at high pT in PbPb collisions at sqrt(sNN) = 2.76 TeV with CMS, Nucl Phys A 910–911 (2013) 339-342, 2013
Krisztián Krajczár for the CMS Collaboration: Measurements of hadron production in pPb collisions in CMS, PoS (EPS-HEP 2013) 181, 2013



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