Measurement of Feynman- $$x$$ x spectra of photons and neutrons in the very forward direction in deep-inelastic scattering at HERA

Andreev, V.; Baghdasaryan, A.; Begzsuren, K.; Belousov, A.; Belov, Pavel A.; Boudry, V.; Brandt, G.; Brinkmann, Martin; Brisson, V.; Britzger, D.; Buniatyan, A.; Bylinkin, A.; Bystritskaya, L.; Campbell, A. J.; Avila, K. B. Cantun; Ceccopieri, Federico Alberto; C̆erný, K.; Chekelian, V.; Contreras, J. G.; Dainton, J. B.; Daum, K.; Diaconu, C.; Dobre, M.; Dodonov, V.; Dossanov, A.; Eckerlin, G.; Egli, S.; Elsen, E.; Favart, L.; Fedotov, A.; Feltesse, J.; Ferencei, J.; Fleischer, M.; Fomenko, A.; Gabathuler, E.; Gayler, J.; Ghazaryan, S.; Glazov, A.; Goerlich, L.; Gogitidze, N.; Gouzevitch, M.; Grab, C.; Grebenyuk, A.; Greenshaw, T.; Grindhammer, G.; Haidt, D.; Henderson, R. C. W.; Herbst, M.; Hladký, J.; Hoffmann, D.; Horisberger, R.; Hreus, T.; Huber, Florian; Jacquet, M.; Janssen, X.; Jung, H.; Kapichine, M.; Kiesling, C.; Klein, M.; Kleinwort, C.; Kogler, R.; Kostka, P.; Kretzschmar, J.; Krüger, K.; Landon, M. P. J.; Lange, W.; Laycock, P.; Lebedev, A.; Levonian, S.; Lipka, K.; List, B.; List, Jenny; Łobodziński, B.; Lytkin, L.; Malinovski, E.; Martyn, H. U.; Maxfield, S. J.; Mehta, A.; Meyer, Andreas Bernhard; Meyer, H.; Meyer, J.; Mikocki, S.; Morozov, A.; Müller, K.; Naumann, T.; Newman, P. R.; Niebuhr, C.; Nowak, G.; Nowak, K.; Olsson, J. E.; Ozerov, D.; Pahl, P.; Pascaud, C.; Patel, G. D.; Pérez, E.; Petrukhin, A.; Pićurić, I.; Pirumov, H.; Pitzl, D.; Plačakytė, R.; Pokorny, B.; Polifka, R.; Povh, Bogdan; Radescu, V.; Raičević, N.; Ravdandorj, T.; Reimer, P.; Rizvi, E.; Robmann, P.; Roosen, R.; Rostovtsev, A.; Rotaru, M.; Rusakov, S. V.; Šálek, D.; Sankey, D. P. C.; Sauter, M.; Sauvan, E.; Schmitt, S.; Schoeffel, L.; Schöning, A.; Schultz‐Coulon, H.‐C.; Sefkow, F.; Shushkevich, S.; Soloviev, Y.; Sopicki, P.; South, D.; Spaskov, V.; Specka, A.; Steder, M.; Stella, B.; Straumann, U.; Sýkora, T.; Thompson, P. D.; Traynor, D.; Truöl, P.; Tsakov, I.; Tseepeldorj, B.; Turnau, J.; Valkárová, A.; Vallée, C.; Mechelen, P. Van; Vazdik, Y.; Wegener, D.; Wünsch, E.; Žáček, J.; Zhang, Zhiqing Philippe; Žlebčík, R.; Zohrabyan, H.; Zomer, F.

doi:10.1140/epjc/s10052-014-2915-2

Cited by 28 publications

(28 citation statements)

References 64 publications

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“…It has proven to be very difficult to extract F L from HERA data. Special runs at the end of HERA operation provided data that confirmed [17,18] the expectation [19,20] that F L is small compared to F 2 within the experimentally accessible range of Q 2 ≥ 1.5 GeV 2 . In order to describe data with Q 2 as low as 1.5 GeV 2 , a twist-four term was added to the description of F L within the standard DGLAP formalism for the HHT analysis [8].…”

Section: Hera Data Cross Sections and Structure Functionssupporting

confidence: 60%

Investigation into the limits of perturbation theory at low Q2 using HERA deep inelastic scattering data

et al. 2017

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A phenomenological study of the final combined HERA data on inclusive deep inelastic scattering has been performed. The data are presented and investigated for a kinematic range extending from values of the four-momentum transfer, Q 2 , above 10 4 GeV 2 down to the lowest values observable at HERA ofand Bjorken x, x Bj ¼ 6 × 10 −7 . The data are well described by fits based on perturbative quantum chromodynamics (QCD) using collinear factorisation and evolution of the parton densities encompassed in the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi formalism from the highest Q 2 down to Q 2 of a few GeV 2 . The Regge formalism with the soft Pomeron pole can describe the data up to Q 2 ≈ 0.65 GeV 2 . The complete data set can be described by a new fit using the Abramowicz-LevinLevy-Maor parametrization. The region between the Regge and the perturbative QCD regimes is of particular interest.

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Section: Hera Data Cross Sections and Structure Functionssupporting

confidence: 60%

Investigation into the limits of perturbation theory at low Q2 using HERA deep inelastic scattering data

et al. 2017

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“…The multiplicity distributions of hadrons with x F < ∼ −0.2 are approximately independent of Q 2 for fixed x. Scaling of the distributions is observed in all quoted electron and muon experiments, covering the valence region x > 0.2 [61], the region x < ∼ 0.1 [25,[62][63][64], and the small-x region x < 10 −2 [65][66][67][68]. This behavior is consistent with theoretical expectations based on QCD factorization of the conditional DIS cross sections in the target fragmentation region [30,31].…”

Section: Experimental Distributionsmentioning

confidence: 99%

Electron-deuteron deep-inelastic scattering with spectator nucleon tagging and final-state interactions at intermediate x

Strikman

Weiß

2018

Phys. Rev. C

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We consider electron-deuteron deep-inelastic scattering (DIS) with detection of a proton in the nuclear fragmentation region ("spectator tagging") as a method for extracting the free neutron structure functions and studying their nuclear modifications. Such measurements could be performed at a future Electron-Ion Collider (EIC) with suitable forward detectors. The measured proton recoil momentum ( < ∼ 100 MeV in the deuteron rest frame) specifies the deuteron configuration during the high-energy process and permits a controlled theoretical treatment of nuclear effects. Nuclear and nucleonic structure are separated using methods of light-front quantum mechanics. The impulse approximation (IA) to the tagged DIS cross section contains the free neutron pole, which can be reached by on-shell extrapolation in the recoil momentum. Final-state interactions (FSI) distort the recoil momentum distribution away from the pole. In the intermediate-x region 0.1 < x < 0.5 FSI arise predominantly from interactions of the spectator proton with slow hadrons produced in the DIS process on the neutron (rest frame momenta < ∼ 1 GeV, target fragmentation region). We construct a schematic model describing this effect, using final-state hadron distributions measured in nucleon DIS experiments and low-energy hadron scattering amplitudes. We investigate the magnitude of FSI, their dependence on the recoil momentum (angular dependence, forward/backward regions), their analytic properties, and their effect on the on-shell extrapolation. We comment on the prospects for neutron structure extraction in tagged DIS with EIC. We discuss possible extensions of the FSI model to other kinematic regions (large/small x). In tagged DIS at x ≪ 0.1 FSI resulting from diffractive scattering on the nucleons become important and require separate treatment.deuteron using LF quantum mechanics, including the IA and FSI amplitudes. We use empirical hadron distributions, measured in ep/ed DIS, to describe the slow part of the hadronic final state produced on the nucleon in the deuteron. The interactions of the slow hadrons with the spectator are treated as on-shell scattering with an effective cross section. Off-shell effects can be absorbed into the effective cross section and the slow hadron distribution; they are physically indistinguishable from effects of the finite hadron formation time and can consistently be accounted for in this way. This model amounts to a minimal description of FSI based on the space-time evolution of the DIS process and empirical hadron distributions.In the present study we use the apparatus of LF quantum mechanics to describe the initial-state nuclear structure and final-state interactions in tagged DIS. High-energy processes such as DIS effectively probe a strongly interacting system at fixed LF time x + = x 0 + x 3 , along the direction defined by the reaction axis. In LF quantization one follows the time evolution of the system in x + and describes its structure by wave functions and densities at x + = const. [32][33][34][35][36]....

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“…the proton beam direction in deepinelastic ep scattering [67,68]. This measurement provides new information to improve the understanding of proton fragmentation.…”

Section: Feynman Scaling In Photon and Neutron Productionmentioning

confidence: 99%

WG4 Highlights: QCD and Hadronic Final States

Braun¹,

Britzger²,

Kousouris³

2014

Proceedings of XXII. International Workshop on Deep-Inelastic Scattering and Related Subjects — PoS(DIS2014)

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Measurement of Feynman- $$x$$ x spectra of photons and neutrons in the very forward direction in deep-inelastic scattering at HERA

Cited by 28 publications

References 64 publications

Investigation into the limits of perturbation theory at low Q2 using HERA deep inelastic scattering data

Investigation into the limits of perturbation theory at low Q2 using HERA deep inelastic scattering data

Electron-deuteron deep-inelastic scattering with spectator nucleon tagging and final-state interactions at intermediate x

WG4 Highlights: QCD and Hadronic Final States

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