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Now showing items 1 - 11 of 11

  • High precision measurement of Compton scattering in the 5 GeV region

    Ambrozewicz, P.   Ye, L.   Prok, Y.   Larin, I   Ahmidouch, A.   Baker, K.   Baturin, V   Benton, L.   Bernstein, A.   Burkert, V   Clinton, E.   Cole, P. L.   Collins, P.   Dale, D.   Danagoulian, S.   Davidenko, G.   Demirchyan, R.   Deur, A.   Dolgolenko, A.   Dutta, D.   Dzyubenko, G.   Evdokimov, A.   Fedotov, G.   Feng, J.   Gabrielyan, M.   Gan, L.   Gao, H.   Gasparian, A.   Gevorkyan, N.   Gevorkyan, S.   Glamazdin, A.   Goryachev, V   Guo, L.   Gyurjyan, V   Hardy, K.   He, J.   Isupov, E.   Ito, M. M.   Jiang, L.   Kang, H.   Kashy, D.   Khandaker, M.   Kingsberry, P.   Klein, F.   Kolarkar, A.   Konchatnyi, M.   Korchin, O.   Korsch, W.   Kosinov, O.   Kowalski, S.   Kubantsev, M.   Kubarovsky, A.   Kubarovsky, V   Lawrence, D.   Li, X.   Levillain, M.   Lu, H.   Ma, L.   Martel, P.   Matveev, V   McNulty, D.   Mecking, B.   Micherdzinska, A.   Milbrath, B.   Minehart, R.   Miskimen, R.   Mochalov, V   Morrison, B.   Mtingwa, S.   Nakagawa, I   Overby, S.   Pasyuk, E.   Payen, M.   Park, K.   Pedroni, R.   Phelps, W.   Protopopescu, D.   Rimal, D.   Ritchie, B. G.   Romanov, D.   Salgado, C.   Shahinyan, A.   Sitnikov, A.   Sober, D.   Stepanyan, S.   Stephens, W.   Tarasov, V   Taylor, S.   Teymurazyan, A.   Underwood, J.   Vasiliev, A.   Vishnyakov, V.   Weygand, D. P.   Wood, M.   Zhang, Y.   Zhou, S.   Zihlmann, B.  

    The cross section of atomic electron Compton scattering gamma + e -> gamma' + e' was measured in the 4.400-5.475 GeV photon beam energy region by the PrimEx collaboration at Jefferson Lab with an accuracy of 2.6% and less. The results are consistent with theoretical predictions that include next-to-leading order radiative corrections. The measurements provide the first high precision test of this elementary QED process at beam energies greater than 0.1 GeV. (C) 2019 The Author(s). Published by Elsevier B.V.
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  • Measurement of nuclear transparency ratios for protons and neutrons

    Duer, M.   Hen, O.   Piasetzky, E.   Weinstein, L. B.   Schmidt, A.   Korover, I   Cohen, E. O.   Hakobyan, H.   Adhikari, S.   Angelini, G.   Avakian, H.   Gayoso, C. Ayerbe   Barion, L.   Battaglieri, M.   Beck, A.   Bedlinskiy, I   Biselli, A. S.   Boiarinov, S.   Briscoe, W. J.   Brooks, W.   Burkert, V. D.   Cao, F.   Carman, D. S.   Celentano, A.   Chatagnon, P.   Chetry, T.   Ciullo, G.   Cole, P. L.   Contalbrigo, M.   Cortes, O.   Crede, V   Torres, R. Cruz   D'Angelo, A.   Dashyan, N.   De Vita, R.   De Sanctis, E.   Deur, A.   Diehl, S.   Djalali, C.   Dupre, R.   Duran, Burcu   Egiyan, H.   Ehrhart, M.   El Alaoui, A.   El Fassi, L.   Eugenio, P.   Filippi, A.   Forest, T. A.   Gilfoyle, G. P.   Girod, F. X.   Golovatch, E.   Gothe, R. W.   Griffioen, K. A.   Guidal, M.   Guo, L.   Hafidi, K.   Hanretty, C.   Harrison, N.   Hattawy, M.   Hauenstein, F.   Hayward, T. B.   Heddle, D.   Holtrop, M.   Ilievaa, Y.   Ireland, D. G.   Ishkhanov, B. S.   Isupov, E. L.   Jo, H. S.   Johnston, S.   Joo, K.   Joosten, S.   Keller, D.   Khachatryan, G.   Khachatryan, M.   Khanal, A.   Khandaker, M.   Kim, A.   Kim, W.   Klein, A.   Klein, F. J.   Kubarovsky, V   Kuhn, S. E.   Kuleshov, S., V   Lanza, L.   Laskaris, G.   Lenisa, P.   Livingston, K.   MacGregor, I. J. D.   Marchand, D.   McKinnon, B.   Beck, S. Mey-Tal   Mineeva, T.   Mirazita, M.   Mokeev, V   Montgomery, R. A.   Movsisyan, A.   Camacho, C. Munoz   Mustapha, B.   Nadel-Turonski, P.   Niccolai, S.   Niculescu, G.   Osipenko, M.   Ostrovidov, A., I   Paolone, M.   Pappalardo, L. L.   Paremuzyan, R.   Pasyuk, E.   Patsyuk, M.   Payette, D.   Price, J.   Pocanic, D.   Pogorelko, O.   Prok, Y.   Protopopescu, D.   Raue, B. A.   Ripani, M.   Riser, D.   Rizzo, A.   Rosner, G.   Rossi, P.   Sabatie, F.   Salgado, C.   Schmookler, B. A.   Schumacher, R. A.   Segarra, E. P.   Sharabian, Y. G.   Skorodumina, Iu   Sokhan, D.   Soto, O.   Sparveris, N.   Stepanyan, S.   Strauch, S.   Taiuti, M.   Tan, J. A.   Ungaro, M.   Voskanyan, H.   Voutier, E.   Wang, R.   Wei, X.   Zachariou, N.   Zhang, J.   Zhao, Z. W.   Zheng, X.  

    This paper presents, for the first time, measurements of neutron transparency ratios for nuclei relative to C measured using the (e, e'n) reaction, spanning measured neutron momenta of 1.4 to 2.4 GeV/c. The transparency ratios were extracted in two kinematical regions, corresponding to knockout of mean-field nucleons and to the breakup of Short-Range Correlated nucleon pairs. The extracted neutron transparency ratios are consistent with each other for the two measured kinematical regions and agree with the proton transparencies extracted from new and previous (e, e'p) measurements, including those from neutron-rich nuclei such as lead. The data also agree with and confirm the Glauber approximation that is commonly used to interpret experimental data. The nuclear-mass-dependence of the extracted transparencies scales as A(alpha) with alpha =3D -0.289 +/- 0.007, which is consistent with nuclear-surface dominance of the reactions. (C) 2019 The Author. Published by Elsevier B.V.
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  • A new highly segmented start counter for the CLAS detector

    Sharabian, YG   Battaglieri, M   Burkert, VD   DeVita, R   Elouadrhiri, L   Guo, L   Kashy, D   Kubarovsky, V   Mutchler, GS   Ostrick, M   Ripani, M   Rossi, P   Rottura, A   Pasyuk, E   Weygand, D  

    The design, construction and performance of a highly segmented Start Counter are described. The Start Counter is an integral part of the trigger used in photon beam running with CLAS in Hall B at the Thomas Jefferson National Accelerator Facility (TJNAF). The Start Counter is constructed of 24 2,2-mm-thick single-ended scintillation paddles, forming a hermetic hexagon around the target region. This device measures the interaction time of the incoming photon in the target by detecting the outgoing particles. The counter provides complex trigger topologies, shows good efficiency and achieved a time resolution of 350ps. (c) 2005 Elsevier B.V. All rights reserved.
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  • Status of pentaquark search at Jlab

    Kubarovsky, V   Stoler, P  

    We review the current experimental situation of pentaquark searches, and second generation experiments, with emphasis on the Jefferson Lab program.
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  • The RICH detector of the SELEX experiment

    Engelfried, J   Filimonov, I   Kilmer, J   Kozhevnikov, A   Kubarovsky, V   Molchanov, V   Nemitkin, A   Ramberg, E   Rud, V   Stutte, L  

    A RICH detector was used during the 1996/7 fixed target run at Fermilab in experiment E781 - SELEX. The detector utilizes a matrix of 2848 phototubes for the photocathode. The figure of merit, N-o, has been measured to be in excess of 100 cm(-1). The ring radius resolution for multitrack events has been measured to be 1.8 mm, which gives K/pi. separation on a 2 sigma level up to a momentum of 165 GeV/c, and p/pi separation up to 320 GeV/c. We will describe the design of the detector, discuss the stability during operation, and report on achieved results (C) 1999 Elsevier Science B.V. All rights reserved.
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  • The SELEX phototube RICH detector

    Engelfried, J   Filimonov, I   Kilmer, J   Kozhevnikov, A   Kubarovsky, V   Molchanov, V   Nemitkin, A   Ramberg, E   Rud, V   Stutte, L  

    In this article, construction, operation, and performance of the RICH detector of Fermilab experiment 781 (SELEX) are described. The detector utilizes a matrix of 2848 phototubes for the photocathode to detect Cherenkov photons generated in a 10 m neon radiator. For the central region an N-0 of 104 cm(-1), corresponding to 13.6 hits on a beta = 1 ring, was obtained. The ring radius resolution measured is 1.6%. (C) 1999 Published by Elsevier Science B.V. All rights reserved.
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  • Background study for the pentaquark search in the reaction gamma p ->pi(+)Kappa(-)Kappa(+) n

    Guo, L   Weygand, DP   Kubarovsky, V  

    A narrow baryon state with strangeness S=+1 and mass M = 1555 +/- 10 MeV/c(2) reported by the CLAS collaboration in the reaction gamma p -> pi(+)K(-)K(+)n, has been observed at Jefferson Lab using a tagged photon beam with an energy range of 3-5.47 GeV. A thorough investigation on whether background processes, such as pi(2)(1670) production, can reflect into the possible Theta(+) peak was conducted by performing a partial wave analysis on the three-body mesonic background in the energy range of 4.8-5.47 GeV. The analysis also probes other possible processes, and does not find evidence for the observed signal being a result of kinematic reflection.
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  • SPHINX phototube RICH detector for diffractive production experiments at Serpukhov accelerator

    Kozhevnikov, A   Kubarovsky, V   Molchanov, V   Rykalin, V   Solyanik, V  

    The RICH detector used in the SPHINX experiment at the Serpukhov accelerator is described. The optical system of this detector consists of two spherical mirrors with focal length of 125 cm. Two matrices with 736 phototubes in total are used for the photocathode. The standard performance characteristics of the detector are a value of 42 cm(-1) for N-o and a single hit resolution of 0.5 cm. Particle identification capability of the detector is discussed. (C) 1999 Elsevier Science B.V. All rights reserved.
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  • MUON TRIGGER COUNTERS FOR A HADRON COLLIDER EXPERIMENT

    CHAPMAN, JW   DODD, E   HONG, S   MANN, J   THUN, R   WEAVERDYCK, C   YALE, K   KUBAROVSKY, V   RYKALIN, V  

    We describe the design and performance of prototype trigger counters for the SDC muon system. The 1.0 x 48.7 x 178.7 cm scintillation counters feature compact light guides, use standard 2 in. phototubes, and provide good photoelectron yields (> 25) and time resolution (< 1 ns).
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  • Measurement of the beam spin asymmetry of (e)over-right-arrowp -> e ' p 'eta ' in the deep-inelastic regime with CLAS

    Zhao, B.   Kim, A.   Joo, K.   Bedlinskiy, I   Kim, W.   Kubarovsky, V   Ungaro, M.   Adhikari, S.   Akbar, Z.   Angelini, G.   Avakian, H.   Ball, J.   Baltzell, N. A.   Barion, L.   Bashkanov, M.   Battaglieri, M.   Batourine, V   Biselli, A. S.   Boiarinov, S.   Briscoe, W. J.   Brooks, W. K.   Burkert, V. D.   Carman, D. S.   Celentano, A.   Chatagnon, R.   Chetry, T.   Ciullo, G.   Clark, L.   Clary, B. A.   Cole, P. L.   Contalbrigo, M.   Crede, V   D'Angelo, A.   Dashyan, N.   De Vita, R.   De Sanctis, E.   Defurne, M.   Deur, A.   Diehl, S.   Djalali, C.   Dupre, R.   Egiyan, H.   Ehrhart, M.   El Alaoui, A.   El Fassi, L.   Eugenio, R.   Filippi, A.   Forest, T. A.   Gavalian, G.   Ghandilyan, Y.   Gilfoyle, G. P.   Girod, F. X.   Golovatch, E.   Gothe, R. W.   Griffioen, K. A.   Guidal, M.   Guo, L.   Hafidi, K.   Hakobyan, H.   Harrison, N.   Hattawy, M.   Heddle, D.   Hicks, K.   Holtrop, M.   Ilieva, Y.   Ireland, D. G.   Ishkhanov, B. S.   Isupov, E. L.   Jenkins, D.   Jo, H. S.   Johnston, S.   Kabir, M. L.   Keller, D.   Khachatryan, G.   Khachatryana, M.   Khandaker, M.   Klein, A.   Klein, F. J.   Kuhn, S. E.   Kuleshov, S., V   Lanza, L.   Lenisa, R.   Livingston, K.   MacGregor, I. J. D.   Marchand, D.   Markov, N.   McKinnon, B.   Meyer, C. A.   Meziani, Z. E.   Mirazita, M.   Mokeev, V   Montgomery, R. A.   Camacho, C. Munoz   Nadel-Turonski, R.   Niccolai, S.   Niculescu, G.   Osipenko, M.   Ostrovidov, A., I   Paolone, M.   Paremuzyan, R.   Parke, K.   Pogorelko, O.   Price, J. W.   Prok, Y.   Protopopescu, D.   Ripani, M.   Rizzo, A.   Rosner, G.   Rossi, P.   Sabatie, F.   Salgado, C.   Schumacher, R. A.   Sharabian, Y. G.   Skorodumina, Iu   Smith, G. D.   Sokhan, D.   Sparveris, N.   Stepanyan, S.   Strakovsky, I   Strauch, S.   Taiuti, M.   Tan, J. A.   Voskanyan, H.   Voutier, E.   Wang, R.   Wei, X.   Wood, M. H.   Zachariou, N.   Zhang, J.   Zhao, Z. W.  

    The beam spin asymmetry of the exclusive pseudoscalar channel (e) over right arrowp -> e'p'eta was measured for the first time in the deep-inelastic regime (W > 2 GeV/c(2) and Q(2) > 1 GeV2/c(2)) using a longitudinally polarized 5.78 GeV electron beam at Jefferson Lab with the CEBAF Large Acceptance Spectrometer. The data were accumulated in 144 four-dimensional bins of Q(2), chi(B), -t and phi over a wide kinematic range, where phi is the azimuthal angle between the lepton and hadron scattering planes, The measured azimuthal dependence with large amplitudes of the sin phi moments is a clear indication of a substantial contribution to the polarized cross-section from transversely polarized virtual photons. In the framework of generalized parton distributions (GPDs) this contribution is expressed via longitudinal-transverse interference between chiral-even and chiral-odd GPDs. The experimental results are compared to the existing theoretical models demonstrating the sensitivity to the product of chiral-odd and chiral-even GPDs and provide new constraints to the existing GPD parameterizations. (C) 2019 The Authors. Published by Elsevier B.V.
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  • Confirmation of the doubly charmed baryon Epsilon(+)(cc)(3520) via its decay to pD(+)K(-)

    Ocherashvili, A   Moinester, MA   Russ, J   Engelfried, J   Torres, I   Akgun, U   Alkhazov, G   Amaro-Reyes, J   Atamantchouk, AG   Ayan, AS   Balatz, MY   Bondar, NF   Cooper, PS   Dauwe, LJ   Davidenko, GV   Dersch, U   Dolgolenko, AG   Dzyubenko, GB   Edelstein, R   Emediato, L   Endler, AME   Eschrich, I   Escobar, CO   Evdokimov, AV   Filimonov, IS   Garcia, FG   Gaspero, M   Giller, I   Golovtsov, VL   Gouffon, P   Gulmez, E   Kangling, H   Iori, M   Jun, SY   Kaya, M   Kilmer, J   Kim, VT   Kochenda, LM   Konorov, I   Kozhevnikov, AP   Krivshich, AG   Kruger, H   Kubantsev, MA   Kubarovsky, V   Kulyavtsev, AI   Kuropatkin, NP   Kurshetsov, VF   Kushnirenko, A   Kwan, S   Lach, J   Lamberto, A   Landsberg, LG   Larin, I   Leikin, EM   Li, YS   Luksys, M   Lungov, T   Maleev, VP   Mao, D   Mao, CS   Mao, ZL   Mathew, P   Mattson, M   Matveev, V   McCliment, E   Molchanov, VV   Morelos, A   Nelson, KD   Nemitkin, AV   Neoustroev, PV   Newsom, C   Nilov, AP   Nurushev, SB   Onel, Y   Ozel, E   Ozkorucuklu, S   Penzo, A   Petrenko, SV   Pogodin, P   Procario, M   Prutskoi, VA   Ramberg, E   Rappazzo, GF   Razmyslovich, BV   Rud, VI   Schiavon, P   Simon, J   Sitnikov, AI   Skow, D   Smith, VJ   Srivastava, M   Steiner, V   Stepanov, V   Stutte, L   Svoiski, M   Terentyev, NK   Thomas, GP   Uvarov, LN   Vasiliev, AN   Vavilov, DV   Vazquez-Jauregui, E   Verebryusov, VS   Victorov, VA   Vishnyakov, VE   Vorobyov, AA   Vorwalter, K   You, J   Zhao, WH   Zheng, SC   Zukanovich-Funchal, R  

    We observe a signal for the doubly charmed baryon Xi(cc)(+) in the decay mode Xi(cc)(+) -> pD(+)K(-) to complement the previous cc reported decay Xi(cc)(+) -> Lambda(c)(+)K(-)pi(+) in data from SELEX, the charm hadroproduction experiment at Fermilab. In this new decay mode we observe an excess of 5.62 events over a combinatoric background estimated by event mixing to be 1.38 +/- 0.13 events. The mixed background has Gaussian statistics, giving a signal significance of 4.8 sigma. The Poisson probability that a background fluctuation can produce the apparent signal is less than 6.4 x 10(-4). The observed mass of this state is 3518 +/- 3 MeV/c(2), consistent with the published result. Averaging the two results gives a mass of 3518.7 +/- 1.7 MeV/c(2). The observation of this new weak decay mode confirms the previous SELEX suggestion that this state is a double charm baryon. The relative branching ratio for these two modes is 0.36 +/- 0.21. (c) 2005 Elsevier B.V. All rights reserved.
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