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Author |
Noguera, S.; Vento, V. |
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Title |
The pion transition form factor and the pion distribution amplitude |
Type |
Journal Article |
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Year |
2010 |
Publication |
European Physical Journal A |
Abbreviated Journal |
Eur. Phys. J. A |
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Volume |
46 |
Issue |
2 |
Pages |
197-205 |
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Keywords |
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Abstract |
Recent BaBar data on the pion transition form factor, whose Q(2)-dependence is much steeper then predicted by asymptotic Quantum Chromodynamics (QCD), have caused a renewed interest in its theoretical description. We present here a formalism based on a model-independent description for low photon virtuality and a high photon virtuality description based on QCD, which match at a scale Q(0). The high photon virtuality description incorporates a flat pion distribution amplitude, phi(x) = 1, at the matching scale Q(0) and QCD evolution from Q(0) to Q > Q(0). The flat pion distribution is connected, through soft pion theorems and chiral symmetry, to the pion valence parton distribution at the same low scale Q(0). The procedure leads to a good description of the data, and by incorporating additional twist-three effects, to an excellent description of the data. |
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Address |
[Noguera, S.] Univ Valencia, Dept Fis Teor, CSIC, E-46100 Valencia, Spain, Email: Santiago.Noguera@uv.es |
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Springer |
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English |
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Abbreviated Series Title |
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Series Volume |
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Edition |
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ISSN |
1434-6001 |
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Notes  |
ISI:000284869600005 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
no |
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Call Number |
IFIC @ elepoucu @ |
Serial |
312 |
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Author |
Kaskulov, M.; Hernandez, E.; Oset, E. |
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Title |
On the background in the gamma p -> omega(pi(0)gamma)p reaction and mixed event simulation |
Type |
Journal Article |
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Year |
2010 |
Publication |
European Physical Journal A |
Abbreviated Journal |
Eur. Phys. J. A |
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Volume |
46 |
Issue |
2 |
Pages |
223-230 |
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Keywords |
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Abstract |
In this paper we evaluate sources of background of the gamma p -> omega p reaction, with the omega detected through its pi(0)gamma decay channel, to compare with the experiment carried out at ELSA. We find background from gamma p -> pi(0)pi(0)p followed by decay of a pi(0) into two gamma, recombining one pi(0) and one gamma, and from the gamma p -> pi(0)eta p reaction with subsequent decay of the eta into two photons. This background accounts for the data at pi(0)gamma invariant masses beyond 700 MeV, but strength is missing at lower invariant masses which was attributed to photon misidentification events, which we simulate to get a good reproduction of the experimental background. Once this is done, we perform an event mixing simulation to reproduce the calculated background and we find that the method provides a good description of the background. A closer look reveals this is accidental. We show that the mixed event generated background in the region of the omega mass and beyond is completely tied to the events at low pi(0)gamma invariant masses where the d sigma/dM(pi 0 gamma) distribution is much larger. This has as a consequence that the mixed event method produces the same background at high invariant masses independently of the actual background in that region, as a consequence of which, the method is unsuited to give the background at energies around the peak of the omega and beyond. |
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Address |
[Kaskulov, M.] Univ Giessen, Inst Theoret Phys, D-35392 Giessen, Germany, Email: murat.kaskulov@theo.physik.uni-giessen.de |
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Corporate Author |
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Thesis |
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Publisher |
Springer |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1434-6001 |
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Conference |
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Notes |
ISI:000284869600008 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
313 |
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Author |
Doring, M.; Oset, E.; Meissner, U.G. |
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Title |
Evaluation of the polarization observables I-S and I-C in the reaction gamma p -> pi(0)eta p |
Type |
Journal Article |
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Year |
2010 |
Publication |
European Physical Journal A |
Abbreviated Journal |
Eur. Phys. J. A |
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Volume |
46 |
Issue |
2 |
Pages |
315-323 |
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Keywords |
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Abstract |
We evaluate the polarization observables I-S and I-C for the reaction gamma p -> pi(0)eta p, using a chiral unitary framework developed earlier. The I-S and I-C observables have been recently measured for the first time by the CBELSA/TAPS Collaboration. The theoretical predictions of I-S and I-C, given for altogether 18 angle-dependent functions, are in good agreement with the measurements. Also, the asymmetry d Sigma/dcos theta evaluated here agrees with the data. We show the importance of the Delta(1700) D-33-resonance and its S-wave decay into eta Delta(1232). The result can be considered as a further confirmation of the dynamical nature of this resonance. At the highest energies, deviations of the predictions from the data start to become noticeable, which leaves room for additional processes and resonances such as a Delta(1940) D-33. We also point out how to further improve the calculation. |
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Address |
[Doering, M.; Meissner, U. -G.] Forschungszentrum Julich, Inst Kernphys, D-52425 Julich, Germany, Email: m.doering@fz-juelich.de |
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Corporate Author |
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Thesis |
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Publisher |
Springer |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1434-6001 |
ISBN |
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Area |
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Expedition |
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Conference |
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Notes |
ISI:000284869600016 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
314 |
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Author |
Jung, M.; Pich, A.; Tuzon, P. |
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Title |
Charged-Higgs phenomenology in the aligned two-Higgs-doublet model |
Type |
Journal Article |
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Year |
2010 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
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Volume |
11 |
Issue |
11 |
Pages |
003 - 45pp |
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Keywords |
Higgs Physics; Beyond Standard Model; CP violation |
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Abstract |
The alignment in flavour space of the Yukawa matrices of a general two-Higgs-doublet model results in the absence of tree-level flavour-changing neutral currents. In addition to the usual fermion masses and mixings, the aligned Yukawa structure only contains three complex parameters zeta(f), which are potential new sources of CP violation [1]. For particular values of these three parameters all known specific implementations of the model based on discrete Z(2) symmetries are recovered. One of the most distinctive features of the two-Higgs-doublet model is the presence of a charged scalar H-+/-. In this work, we discuss its main phenomenological consequences in flavour-changing processes at low energies and derive the corresponding constraints on the parameters of the aligned two-Higgs-doublet model. |
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Address |
[Jung, Martin; Pich, Antonio; Tuzon, Paula] Univ Valencia, Inst Fis Corpuscular IFIC, CSIC, E-46071 Valencia, Spain, Email: jung@ific.uv.es |
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Corporate Author |
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Thesis |
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Publisher |
Springer |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1126-6708 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
ISI:000284963400078 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
no |
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Call Number |
IFIC @ elepoucu @ |
Serial |
317 |
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Author |
ATLAS Collaboration (Abat, E. et al); Bernabeu Verdu, J.; Castillo Gimenez, V.; Costa, M.J.; Escobar, C.; Ferrer, A.; Garcia, C.; Gonzalez-Sevilla, S.; Higon-Rodriguez, E.; Lacasta, C.; Marti-Garcia, S.; Mitsou, V.A.; Ruiz, A.; Solans, C.; Valero, A.; Valls Ferrer, J.A. |
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Title |
Combined performance studies for electrons at the 2004 ATLAS combined test-beam |
Type |
Journal Article |
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Year |
2010 |
Publication |
Journal of Instrumentation |
Abbreviated Journal |
J. Instrum. |
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Volume |
5 |
Issue |
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Pages |
P11006 - 68pp |
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Keywords |
Particle tracking detectors; Transition radiation detectors; Calorimeters; Large detector systems for particle and astroparticle physics |
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Abstract |
In 2004 at the ATLAS (A Toroidal LHC ApparatuS) combined test beam, one slice of the ATLAS barrel detector (including an Inner Detector set-up and the Liquid Argon calorimeter) was exposed to particles from the H8 SPS beam line at CERN. It was the first occasion to test the combined electron performance of ATLAS. This paper presents results obtained for the momentum measurement p with the Inner Detector and for the performance of the electron measurement with the LAr calorimeter (energy E linearity and resolution) in the presence of a magnetic field in the Inner Detector for momenta ranging from 20 GeV/c to 100 GeV/c. Furthermore the particle identification capabilities of the Transition Radiation Tracker, Bremsstrahlungs-recovery algorithms relying on the LAr calorimeter and results obtained for the E/p ratio and a way how to extract scale parameters will be discussed. |
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Address |
Univ Alberta, Ctr Particle Phys, Dept Phys, Edmonton, AB T6G 2G7, Canada, Email: robert.froesch1@cern.ch |
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Corporate Author |
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Thesis |
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Publisher |
Iop Publishing Ltd |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1748-0221 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
ISI:000285051500031 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
311 |
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| Permanent link to this record |
