250 research outputs found
Parity nonconservation in atomic thallium: the magnetic-field experiment
No full textAn experiment underway to measure the parity-nonconserving electric-dipole amplitude in the 6/sup 2/P/sub 1/2/ ..-->.. 7/sup 2/P/sub 1/2/ transition in atomic thallium is described
Studies of Drell-Yan process with polarized target at COMPASS
No full textTitle: Studies of Drell-Yan process with polarized target at COMPASS Author: Markéta Pešková Department / Institute: Department of Low Temperature Physics Supervisor of the bachelor thesis: M.Sc. Michael Finger, CSc. Abstract: The presented thesis intends to give an introduction into the studies of the spin structure of a nucleon. The knowledge about the structure of nucleon has grown in the last few decades; however, its spin structure is still a mystery. One of the concepts that might help solving this spin puzzle is the polarized Drell-Yan process. This process can give us the access to the spin-dependent structure functions of a nucleon via measuring spin asymmetries. In the following text, an outline of the theoretical background of the semi- inclusive Deep Inelastic Scattering and the Drell-Yan is given. The Parton Distribution Functions (PDFs) and the transverse-momentum-dependent PDFs (TMDs) are discussed. And the way of accessing the TMDs via polarized Drell-Yan process is briefly described. This is the goal of the Drell-Yan program at COMPASS experiment, using the transversely polarized target and pion beam in 2014-15. The description of experimental apparatus is given and the system of collecting and processing data is outlined. The data-taking conditions of the 2009 DY beam test and the 2014 DY..
Extracting Boer-Mulders functions from p+D Drell-Yan processes
No full textWe extract the Boer- Mulders functions of valence and sea quarks in the proton from unpolarized p + D Drell- Yan data measured by the FNAL E866 Collaboration. Using these Boer- Mulders functions, we calculate the cos2 phi asymmetries in unpolarized pp Drell- Yan processes, both for the FNAL E866/ NuSea and the BNL Relativistic Heavy Ion Collider experiments. We also estimate the cos2 phi asymmetries in the unpolarized p (P) over bar Drell- Yan processes at GSI.Astronomy & AstrophysicsPhysics, Particles & FieldsSCI(E)37ARTICLE5null7
Studium procesu Drell-Yan v experimentu Compass s využitím polarizovaného terče
No full textNázev práce: Studium procesu Drell-Yan v experimentu Compass s využitím polarizovaného terče Autor: Markéta Pešková Katedra / Ústav: Katedra fyziky nízkých teplot Vedoucí bakalářské práce: M.Sc. Michael Finger, CSc. Abstrakt: Tato práce se snaží poskytnout úvod do studií spinové struktury nukleonu. Poznání struktury nukleonu se za posledních několik desetiletí prohloubilo, ale jeho spinová struktura je stále záhadou. Polarizovaný Drell-Yan proces je jedním z konceptů, které by mohly pomoci vyřešit otázku spinu nukleonu. Měřením spinových asymetrií v tomto procesu můžeme určit spinově závislé strukturní funkce nukleonu. Následující text obsahuje úvod do teorie semi-inklusivního hlubokého nepružného rozptylu a Drell-Yan procesu. Popisuje partonové distribuční funkce (PDF) a PDF související s příčným momentem hybnosti partonů (TMD). Dále je stručně popsán způsob, jak lze pomocí Drell- Yanova procesu nalézt TMD, což je cílem Drell-Yan programu na experimentu COMPASS s použitím transverzálně polarizovaného terče a pionového svazku v letech 2014 a 2015. Práce dále popisuje spektrometr COMPASS a systém sběru a zpracování dat. Předkládáme podmínky měření při testovacím runu Drell-Yan programu v roce 2009 a při pilotním runu v roce 2014. Z těchto dat jsme zanalyzovali produkci mionového páru a kinematické...Title: Studies of Drell-Yan process with polarized target at COMPASS Author: Markéta Pešková Department / Institute: Department of Low Temperature Physics Supervisor of the bachelor thesis: M.Sc. Michael Finger, CSc. Abstract: The presented thesis intends to give an introduction into the studies of the spin structure of a nucleon. The knowledge about the structure of nucleon has grown in the last few decades; however, its spin structure is still a mystery. One of the concepts that might help solving this spin puzzle is the polarized Drell-Yan process. This process can give us the access to the spin-dependent structure functions of a nucleon via measuring spin asymmetries. In the following text, an outline of the theoretical background of the semi- inclusive Deep Inelastic Scattering and the Drell-Yan is given. The Parton Distribution Functions (PDFs) and the transverse-momentum-dependent PDFs (TMDs) are discussed. And the way of accessing the TMDs via polarized Drell-Yan process is briefly described. This is the goal of the Drell-Yan program at COMPASS experiment, using the transversely polarized target and pion beam in 2014-15. The description of experimental apparatus is given and the system of collecting and processing data is outlined. The data-taking conditions of the 2009 DY beam test and the 2014 DY...Department of Low Temperature PhysicsKatedra fyziky nízkých teplotFaculty of Mathematics and PhysicsMatematicko-fyzikální fakult
Azimuthal asymmetries in single polarized proton-proton Drell-Yan processes
No full textWe study the azimuthal asymmetries in proton-proton Drell-Yan processes with one incident proton being transversely or longitudinally polarized. We consider particularly the asymmetries contributed by the leading-twist chiral-odd quark distributions. We analyze the asymmetries with sin(2 phi + phi(S)) and sin(2 phi - phi(S)) modulations in transverse single polarized p(up arrow)p Drell-Yan and sin2 phi asymmetries in longitudinal single polarized p(->)p Drell-Yan at the Relativistic Heavy Ion Collider, the Japan Proton Accelerator Research Complex, E906 (Fermi Lab), and the Nuclotron-based Ion Collider Facility (Joint Institute for Nuclear Research). We show that the measurements of the asymmetries in those facilities can provide valuable information of the chiral-odd structure of the nucleon both in the valence and sea regions.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000296887600004&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Astronomy & AstrophysicsPhysics, Particles & FieldsSCI(E)7ARTICLE7null8
Study of azimuthal asymmetries in COMPASS Drell-Yan data
No full textTitle: Study of azimuthal asymmetries in COMPASS Drell-Yan data Author: Bc. Markéta Pešková Department / Institute: Department of Low Temperature Physics Supervisor of the master thesis: M.Sc. Michael Finger, CSc. Abstract: Drell-Yan (DY) process, i.e. a lepton pair production in hadron-hadron interaction, is one of the unique tools to study structure of hadrons. In this thesis we present its theoretical background and its link to description of the nucleon spin structure. The corresponding formalism of the Parton Distribution Functions (PDF) and the Transverse Momentum Dependent Parton Distribution Functions (TMD PDF) is explained in some detail. The fundamental theoretical prediction of a sign change of the T-odd TMDs in the DY and Semi- inclusive DIS (SIDIS) is described. In the following a concise description of the COMPASS apparatus is given with the emphasis on the setup modification needed and implemented for the Drell-Yan measurement performed in 2014 and 2015 with 190 GeV/c2 beam of negative pions and the proton target (polarised in 2015). In the final chapter we present our independent analysis of the DY data taken in 2015. Three azimuthal asymmetries giving access to the different TMD PDF were extracted using the dimuon events from a mass region of 4.3 to 8.5 GeV/c2 . Our results are in agreement..
Studium spinové struktury nukleonu s pomocí procesu Drell-Yan v experimentu Compass
No full textDoktorská práce pod dvojím vedením Název: Studium spinové struktury nukleonu s pomocí procesu Drell-Yan v ex- perimentu COMPASS Autor: Jan Matoušek Abstrakt: Struktura nukleonů je v současné době popisována pomocí partonových dis- tribučních funkcí závislých na příčné hybnosti (TMD PDF), které zobecňují ko- lineární PDF a zohledňují spin a příčnou hybnost partonů. Nedávná měření pro- dukce hadronů v hluboce nepružném rozptylu (SIDIS) leptonů na příčně polarizo- vaných protonech, provedená na experimentech HERMES a COMPASS, přinesla důkazy platnosti tohoto modelu. Nicméně, je důležité studovat také další reakce, jako jsou tvrdé srážky protonů a proces Drell-Yan. Například, Siversova TMD PDF, která popisuje korelaci spinu nukleonu a příčné hybnosti kvarku a projevuje se jako Siversova asymetrie, by měla mít opačné zmanénko v procesech Drell-Yan a SIDIS. V roce 2015 COMPASS naměřil Drell- Yan proces s příčně polarizovaným terčem π− p↑ → µ− µ+ X, aby tuto předpověd' jako první ověřil. Výsledky byly nedávno publikovány. Hlavním tématem mojí práce je první měření spinových asymetrií vážených příčnou hybností mionového páru ze stejných dat. Vážené asymetrie doplňují ty klasické, jejich výhoda...Jointly-supervised doctoral thesis Title: Nucleon spin structure studies in Drell-Yan process at COMPASS Author: Jan Matoušek Department I: Department of Low Temperature Physics, Faculty of Mathem- atics and Physics, Charles University Department II: Department of Physics, University of Trieste Supervisor I: prof. Miroslav Finger (Department I) Supervisor II: prof. Anna Martin (Department II) Abstract: The nucleon structure is presently described by Transverse Momentum Depend- ent (TMD) Parton Distribution Functions (PDFs), which generalise the collinear PDFs, adding partonic spin and transverse momentum degrees of freedom. The recent HERMES and COMPASS data on hadron production in deep inelastic scattering (SIDIS) of leptons off transversely polarised nucleons have provided a decisive validation of this framework. Nevertheless, the TMD PDFs should be studied in complementary reactions, like pp hard scattering and Drell-Yan pro- cesses. In particular the Sivers TMD PDF, which encodes the correlation between the nucleon transverse spin and quark transverse momentum and appears in the Sivers Transverse Spin Asymmetry (TSA), is expected to have opposite sign in Drell-Yan and SIDIS. In 2015 COMPASS measured for the first time the Drell- Yan process on a transversely polarised target π− p↑ → µ− µ+ X to test...Katedra fyziky nízkých teplotDepartment of Low Temperature PhysicsMatematicko-fyzikální fakultaFaculty of Mathematics and Physic
Studium azimutálních asymetrií v processu Drell-Yan na zařízení COMPASS.
No full textNázev práce: Studium azimutálních asymetríí v processu Drell-Yan na zařízení COMPASS Autor: Bc. Markéta Pešková Katedra / Ústav: Katedra fyziky nízkých teplot Vedoucí diplomové práce: M.Sc. Michael Finger, CSc. Abstrakt: Drell-Yan (DY) process, čili produkce leptonového páru z hadron-hadronové interakce, je jedním z unikátních nástrojů ke studiu hadronové struktury. V této práci představujeme teoretické pozadí za tímto procesem a jeho souvislost s popisem spinové struktury nukleonu. Je popsán formalismus Partonových Distribučních Funkcí (PDF) a PDF závislých na příčné hybnosti (TMD PDF), který s tímto procesem úzce souvisí. Dále je vysvětlena zásadní teoretická předpověď týkající se TMD PDF lichých při otočení času o změně jejich znaménka při měření v DY a v Semi- inkluzivním hlubokém nepružném rozptylu (SIDIS), kterou se snaží potvrdit experiment COMPASS. Experiment je stručně popsán v další části práce s důrazem na modifikace potřebné k měření DY procesu provedeného v letech 2014 a 2015 se 190 GeV/c2 svazkem záporně nabitých pionů na protonovém terči (v roce 2015 polarizovaném). V poslední části přinášíme výsledky naší nezávislé analýzy dat z roku 2015. Byly extrahovány tři azimutální asymetrie, které dávají přístup k různým TMD, s použitím dat s koncovým stavem o dvou mionech a invariantní hmotě od 4.3...Title: Study of azimuthal asymmetries in COMPASS Drell-Yan data Author: Bc. Markéta Pešková Department / Institute: Department of Low Temperature Physics Supervisor of the master thesis: M.Sc. Michael Finger, CSc. Abstract: Drell-Yan (DY) process, i.e. a lepton pair production in hadron-hadron interaction, is one of the unique tools to study structure of hadrons. In this thesis we present its theoretical background and its link to description of the nucleon spin structure. The corresponding formalism of the Parton Distribution Functions (PDF) and the Transverse Momentum Dependent Parton Distribution Functions (TMD PDF) is explained in some detail. The fundamental theoretical prediction of a sign change of the T-odd TMDs in the DY and Semi- inclusive DIS (SIDIS) is described. In the following a concise description of the COMPASS apparatus is given with the emphasis on the setup modification needed and implemented for the Drell-Yan measurement performed in 2014 and 2015 with 190 GeV/c2 beam of negative pions and the proton target (polarised in 2015). In the final chapter we present our independent analysis of the DY data taken in 2015. Three azimuthal asymmetries giving access to the different TMD PDF were extracted using the dimuon events from a mass region of 4.3 to 8.5 GeV/c2 . Our results are in agreement...Department of Low Temperature PhysicsKatedra fyziky nízkých teplotFaculty of Mathematics and PhysicsMatematicko-fyzikální fakult
Measurement of the Differential Production Cross Section of W Bosons and Charge Asymmetry at �s = 7 TeV with the ATLAS Detector
No full textThis document presents a measurement of the production cross section of W
bosons and of its charge asymmetry in proton-proton collisions at a centre of mass energy of 7 TeV with the ATLAS detector. These measurements provide information on the momentum fraction of the protons carried by the partons contributing to the W production and therefore allow to better understand the parton distribution functions of the proton.
The W candidate events are selected in the W�enu decay mode. The LAr electromagnetic calorimeter plays an important role in the detection of electrons and the author has worked on the on-line energy reconstruction in the LAr detectors. A subject which is treated in some detail is the evaluation of the charge misidentification rates for electrons and positrons. This is a key ingredient for charge related measurements such as the W charge asymmetry.
In this document, the W production cross section times the branching ratio is studied inclusively, as a function of the lepton pseudorapidity and as a double differential measurement as a function of the lepton pseudorapidity and transverse energy. The charge asymmetry measurement is presented as a function of the lepton pseudorapidity and as a double differential measurement as well. The data were recorded by the ATLAS detector in 2011 and correspond to 4.7 fb�1
sin2 phi azimuthal asymmetry in single longitudinally polarized pi N Drell-Yan process
No full textWe study the sin2 phi azimuthal asymmetry in the pi N Drell-Yan process, when the nucleon is longitudinally polarized. The asymmetry is contributed by the combination of the Boer-Mulders function and the longitudinal transversity distribution function. We consider the Drell-Yan processes by pi(+/-) beams colliding on the proton and deuteron targets, respectively. We calculate the sin2 phi azimuthal asymmetries in these processes using the Boer-Mulders function and the longitudinal transversity from spectator models. We show that the study on single polarized pi N Drell-Yan processes can not only give the information on the new three-dimensional parton distribution functions in momentum space but also shed light on the chiral-odd structure of the longitudinally polarized nucleon.Astronomy & AstrophysicsPhysics, Particles & FieldsSCI(E)4ARTICLE3null8
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