Spin density matrix elements in exclusive ρ 0 electroproduction on 1H and 2H targets at 27.5 GeV beam energy

Airapetian, A.; Акопов, Н.; Akopov, Z.; Andrus, A.; Aschenauer, E. C.; Augustyniak, W.; Avakian, R.; Avetissian, A.; Avetissian, E.; Belostotski, S.; Bianchi, N.; Blok, H.P.; Böttcher, H.; Bonomo, C.; Borissov, A.; Brüll, A.; Bryzgalov, V.; Capiluppi, M.; Capitani, G. P.; Cisbani, E.; Ciullo, G.; Contalbrigo, M.; Dalpiaz, P.; Deconinck, W.; Лео, Р. Де; Demey, M.; Nardo, L. De; Sanctis, E. De; Diefenthaler, M.; Nezza, P. Di; Dreschler, J.; Düren, M.; Ehrenfried, M.; Elalaoui-Moulay, A.; Elbakian, G.; Ellinghaus, F.; Elschenbroich, U.; Fabbri, R.; Fantoni, A.; Felawka, L.; Frullani, S.; Funel, A.; Gabbert, D.; Gapienko, G.; Гапиенко, В. А.; Garibaldi, F.; Gavrilov, G.; Gharibyan, V.; Giordano, F.; Gliske, S.; Grebeniouk, O.; Gregor, I. M.; Güler, H.; Hadjidakis, C.; Hartig, M.; Hasch, D.; Hasegawa, T.; Hesselink, W.H.A.; Hill, G.; Hillenbrand, A.; Hoek, M.; Holler, Y.; Hommez, B.; Hristova, I.; Iarygin, G.; Imazu, Y.; Ivanilov, A.; Izotov, A.; Jackson, H. E.; Jgoun, A.; Kaiser, R.; Keri, T.; Kinney, E.; Kisselev, A.; Kobayashi, T.; Kopytin, M.; Коротков, В. А.; Kozlov, V.; Kravchenko, P.; Krivokhijine, V. G.; Lagamba, L.; Lamb, R.; Lapikás, L.; Lehmann, I.; Lenisa, P.; Liebing, P.; Linden-Levy, L. A.; Lorenzon, W.; Lu, Shaojun; Lu, X. R.; Ma, Bo-Qiang; Maiheu, B.; Makins, N.; Manaenkov, S.; Mao, Y.; Mariański, B.; Marukyan, H.; Mexner, V.; Miller, C. A.; Miyachi, Y.; Muccifora, V.; Murray, M.; Mussgiller, A.; Нагайцев, А.; Nappi, E.; Naryshkin, Y.; Nass, A.; Negodaev, M.; Nowak, W.-D.; Osborne, A.M.; Pappalardo, L. L.; Pérez-Benito, R.; Pickert, N.; Raithel, Martin; Reggiani, D.; Reimer, P. E.; Reischl, A.; Reolon, A. R.; Riedl, C.; Rith, Klaus; Rock, S. E.; Rosner, G.; Rostomyan, A.; Rubáček, L.; Rubin, J.; Ryckbosch, D.; Salomatin, Y.; Sanjiev, I.; Schäfer, Andreas; Schnell, G.; Schüler, K. P.; Seitz, B.; Shearer, C.; Shibata, T. A.; Shutov, V.; Stancari, M.; Statera, M.; Steffens, J. E.; Steijger, J. J. M.; Stenzel, H.; Stewart, J.; Stinzing, F.; Streit, J.; Tait, P.; Taroian, S.; Tchuiko, B.; Terkulov, A.; Trzciński, A.; Tytgat, M.; Vandenbroucke, A.; Nat, P. B. van der; Steenhoven, G. van der; Haarlem, Y. Van; Hulse, C. Van; Varanda, M.; Veretennikov, D.; Vikhrov, V.; Vilardi, I.; Vogel, Christian; Wang, S.; Yaschenko, S.; Ye, H.; Ye, Y.; Ye, Z.; Yen, S.; Yu, W.; Zeiler, D.; Zihlmann, B.; Żuprański, P.

doi:10.1140/epjc/s10052-009-1082-3

Cited by 51 publications

(110 citation statements)

References 58 publications

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“…[15,16] that factorization also holds for the amplitudes F 1 1 2 1± 1 2 and F 0 1 2 1± 1 2 , which describe the transition from a transversely polarized virtual photon to a transversely polarized meson, γ * T → V T , and a longitudinally polarized meson, γ * T → V L , respectively. The agreement found between certain calculated SDMEs and those extracted from HERMES [17], ZEUS [18], and H1 [19] data supports this assumption. In general, the differential and total cross sections for ρ 0 -meson production by virtual photons are reasonably well described in the GPD-based approach of Refs.…”

Section: Introductionsupporting

confidence: 66%

“…Contributions of squares of moduli of the helicity-amplitude ratios u (1) 01 , u (1) 10 , u (1) 1−1 to u λ V λ V λ γ λ γ are much smaller than the contribution of |u (1) 11 | 2 according to the hierarchy of amplitudes established in Refs. [17] and [27]. The small helicity amplitude ratios u (1) λ V λ γ with λ V = λ γ contribute linearly to the SDMEs l λ V λ V λ γ λ γ .…”

Section: Choice Of Free Parametersmentioning

confidence: 96%

“…(52), a dedicated PYTHIA Monte Carlo (MC) [42] simulation was used to generate exclusively produced ρ 0 events with a uniform angular distribution, hereafter referred to as "uniform exclusive ρ 0 MC" [17,38]. The total number of generated events is by a factor of one hundred larger than that of the experimental data.…”

Section: Fit Of the Angular Distributionmentioning

confidence: 99%

“…[17,45,46], corresponds to the value A ρ 1 = 0.24 (see Appendix A). The systematic uncertainty due to the omission of all inaccessible amplitude ratios is estimated from the relation …”

Section: Systematic Uncertainty Due To the Omission Of Inaccessible Amentioning

confidence: 99%

“…The results of the analysis of ρ 0 -meson and ω-meson production on the unpolarized targets at HERMES using the SDME method were published in Refs. [17] and [28], respectively. The SDMEs for the electroproduction on transversely polarized protons were published in Ref.…”

Section: Introductionmentioning

confidence: 99%

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Ratios of helicity amplitudes for exclusive $$\rho ^0$$ ρ 0 electroproduction on transversely polarized protons

et al. 2017

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Exclusive ρ 0 -meson electroproduction is studied by the HERMES experiment, using the 27.6 GeV longitudinally polarized electron/positron beam of HERA and a transversely polarized hydrogen target, in the kinematic region 1.0 GeV 2 < Q 2 < 7.0 GeV 2 , 3.0 GeV < W < 6.3 GeV, and −t < 0.4 GeV 2 . Using an unbinned maximum-likelihood method, 25 parameters are extracted. These determine the real and imaginary parts of the ratios of several helicity amplitudes describing ρ 0 -meson production by a virtual photon. The denominator of those ratios is the dominant amplitude, the nucleon-helicity-non-flip amplitude F 0 1 2 0 1 2 , which describes the production of a longitudinal ρ 0 -meson by a longitudinal virtual photon. The ratios of nucleon-helicity-nonflip amplitudes are found to be in good agreement with those from the previous HERMES analysis. The transverse target polarization allows for the first time the extraction of ratios of a number of nucleon-helicity-flip amplitudes to F 0 1 2 0 1 2 . Results obtained in a handbag approach based on generalized parton distributions taking into account the contribution from pion exchange are found to be in good agreement with these ratios. Within the model, the data favor a positive sign for the π − ρ transition form factor. By also exploiting the longitudinal beam polarization, a total of 71 ρ 0 spin-density matrix elements is determined from the extracted 25 parameters, in contrast to only 53 elements as directly determined in earlier analyses.

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Section: Introductionsupporting

confidence: 66%

Section: Choice Of Free Parametersmentioning

confidence: 96%

Section: Fit Of the Angular Distributionmentioning

confidence: 99%

“…[17,45,46], corresponds to the value A ρ 1 = 0.24 (see Appendix A). The systematic uncertainty due to the omission of all inaccessible amplitude ratios is estimated from the relation …”

Section: Systematic Uncertainty Due To the Omission Of Inaccessible Amentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Ratios of helicity amplitudes for exclusive $$\rho ^0$$ ρ 0 electroproduction on transversely polarized protons

et al. 2017

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Untitled

Pappalardo¹

2017

Light Cone 2015

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Abstract. The purpose of this research is making an ordering food application based on Android with New Order, Order History, Restaurant Profile, Order Status, Tracking Order, and Setting Profile features. The research method used in this research is water model of System Development Life Cycle (SDLC) method with following phases: requirement definition, analyzing and determining the features needed in developing application and making the detail definition of each features, system and software design, designing the flow of developing application by using storyboard design, user experience design, Unified Modeling Language (UML) design, and database structure design, implementation an unit testing, making database and translating the result of designs to programming language code then doing unit testing, integration and System testing, integrating unit program to one unit system then doing system testing, operation and maintenance, operating the result of system testing and if any changes and reparations needed then the previous phases could be back. The result of this research is an ordering food application based on Android for customer and courier user, and a website for restaurant and admin user. The conclusion of this research is to help customer in making order easily, to give detail information needed by customer, to help restaurant in receiving order, and to help courier while doing delivery.

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Diffractive electroproduction of ρ and ϕ mesons at HERA

Aaron¹,

Martin²,

Alexa³

et al. 2010

J. High Energ. Phys.

115

107

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Diffractive electroproduction of ρ and φ mesons is measured at HERA with the H1 detector in the elastic and proton dissociative channels. The data correspond to an integrated luminosity of 51 pb −1 . About 10500 ρ and 2000 φ events are analysed in the kinematic range of squared photon virtuality 2.5 ≤ Q 2 ≤ 60 GeV 2 , photon-proton centre of mass energy 35 ≤ W ≤ 180 GeV and squared four-momentum transfer to the proton |t| ≤ 3 GeV 2 . The total, longitudinal and transverse cross sections are measured as a function of Q 2 , W and |t|. The measurements show a transition to a dominantly "hard" behaviour, typical of high gluon densities and small qq dipoles, for Q 2 larger than 10 to 20 GeV 2 . They support flavour independence of the diffractive exchange, expressed in terms of the scaling variable (Q 2 +M 2 V )/4, and proton vertex factorisation. The spin density matrix elements are measured as a function of kinematic variables. The ratio of the longitudinal to transverse cross sections, the ratio of the helicity amplitudes and their relative phases are extracted. Several of these measurements have not been performed before and bring new information on the dynamics of diffraction in a QCD framework. The measurements are discussed in the context of models using generalised parton distributions or universal dipole cross sections.

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Spin density matrix elements in exclusive ρ 0 electroproduction on 1H and 2H targets at 27.5 GeV beam energy

Cited by 51 publications

References 58 publications

Ratios of helicity amplitudes for exclusive $$\rho ^0$$ ρ 0 electroproduction on transversely polarized protons

Ratios of helicity amplitudes for exclusive $$\rho ^0$$ ρ 0 electroproduction on transversely polarized protons

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Diffractive electroproduction of ρ and ϕ mesons at HERA

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