Analysis of the exclusive final state npe+e- in the quasi-free np reaction

被引：12

作者：

Adamczewski-Musch, J. ^{[4
]}

Arnold, O. ^{[9
,10
]}

Atomssa, E. T. ^{[15
]}

Behnke, C. ^{[8
]}

Belounnas, A. ^{[15
]}

Belyaev, A. ^{[7
]}

Berger-Chen, J. C. ^{[9
,10
]}

Biernat, J. ^{[3
]}

Blanco, A. ^{[2
]}

Blume, C. ^{[8
]}

Boehmer, M. ^{[10
]}

Bordalo, P. ^{[2
]}

Chernenko, S. ^{[7
]}

Chlad, L. ^{[16
]}

Deveaux, C. ^{[11
]}

Dreyer, J. ^{[6
]}

Dybczak, A. ^{[3
]}

Epple, E. ^{[9
,10
]}

Fabbietti, L. ^{[9
,10
]}

Fateev, O. ^{[7
]}

Filip, P. ^{[1
]}

Fonte, P. ^{[2
,19
]}

Franco, C. ^{[2
]}

Friese, J. ^{[10
]}

Froehlich, I. ^{[8
]}

Galatyuk, T. ^{[4
,5
]}

Garzon, J. A. ^{[17
]}

Gernhaeuser, R. ^{[10
]}

Golubeva, M. ^{[12
]}

Guber, F. ^{[12
]}

Gumberidze, M. ^{[5
,20
]}

Harabasz, S. ^{[3
,5
]}

Heinz, T. ^{[4
]}

Hennino, T. ^{[15
]}

Hlavac, S. ^{[1
]}

Höhne, C. ^{[11
]}

Holzmann, R. ^{[4
]}

Ierusalimov, A. ^{[7
]}

Ivashkin, A. ^{[12
]}

Kaempfer, B. ^{[6
,21
]}

Karavicheva, T. ^{[12
]}

Kardan, B. ^{[8
]}

Koenig, I. ^{[4
]}

Koenig, W. ^{[4
]}

Kolb, B. W. ^{[4
]}

Korcyl, G. ^{[3
]}

Kornakov, G. ^{[5
]}

Kotte, R. ^{[6
]}

Kuehn, W. ^{[11
]}

Kugler, A. ^{[16
]}

机构：

[1] Slovak Acad Sci, Inst Phys, Bratislava 84228, Slovakia

[2] LIP Lab Instrumentacao & Fis Expt Particulas, P-3004516 Coimbra, Portugal

[3] Jagiellonian Univ Cracow, Smoluchowski Inst Phys, PL-30059 Krakow, Poland

[4] GSI Helmholtzzentrum Schwerionenforsch GmbH, D-64291 Darmstadt, Germany

[5] Tech Univ Darmstadt, D-64289 Darmstadt, Germany

[6] Helmholtz Zentrum Dresden Rossendorf, Inst Strahlenphys, D-01314 Dresden, Germany

[7] Joint Inst Nucl Res, Dubna 141980, Russia

[8] Goethe Univ, Inst Kernphys, D-60438 Frankfurt, Germany

[9] Excellence Cluster Origin & Struct Universe, D-85748 Garching, Germany

[10] Tech Univ Munich, Phys Dept E62, D-85748 Garching, Germany

[11] Justus Liebig Univ Giessen, Phys Inst 2, D-35392 Giessen, Germany

[12] Russian Acad Sci, Inst Nucl Res, Moscow 117312, Russia

[13] Inst Theoret & Expt Phys, Moscow 117218, Russia

[14] Univ Cyprus, Dept Phys, CY-1678 Nicosia, Cyprus

[15] Univ Paris Saclay, Univ Paris Sud, Inst Phys Nucl, CNRS,IN2P3, F-91406 Orsay, France

[16] Czech Acad Sci, Nucl Phys Inst, Rez 25068, Czech Republic

[17] Univ Santiago de Compostela, LabCAF F Fis, Santiago De Compostela 15706, Spain

[18] NRC Kurchatov Inst, PNPI, Gatchina 188300, Russia

[19] ISEC Coimbra, Coimbra, Portugal

[20] ExtreMe Matter Inst EMMI, D-64291 Darmstadt, Germany

[21] Tech Univ Dresden, D-01062 Dresden, Germany

[22] Univ Utrecht, NL-3584 CC Utrecht, Netherlands

[23] State Univ, Moscow Engn Phys Inst, Moscow 115409, Russia

[24] Frederick Univ, CY-1036 Nicosia, Cyprus

[25] Univ Turin, Dipartimento Fis, I-10125 Turin, Italy

[26] Univ Turin, Ist Nazl Fis Nucl, I-10125 Turin, Italy

[27] Univ Bonn, Helmholtz Inst Strahlen & Kernphys, Bonn, Germany

来源：

EUROPEAN PHYSICAL JOURNAL A | 2017年 / 53卷 / 07期

关键词：

PROTON-PROTON COLLISIONS; HEAVY-ION COLLISIONS; PION-PRODUCTION; CROSS-SECTIONS; DILEPTON PRODUCTION; BEAM ENERGIES; PP; RADIATION; HADES;

D O I：

10.1140/epja/i2017-12341-3

中图分类号：

O57 [原子核物理学、高能物理学];

学科分类号：

070202 ;

摘要：

We report on the investigation of dielectron production in tagged quasi-free neutron-proton collisions by using a deuteron beam of kinetic energy 1.25 GeV/u impinging on a liquid hydrogen target. Our measurements with HADES confirm a significant excess of e(+)e(-) pairs above the pi(0) mass in the exclusive channel dp -> npe(+)e(-)(p(spect)) as compared to the exclusive channel ppe(+)e(-) measured in proton-proton collisions at the same energy. That excess points to different bremsstrahlung production mechanisms. Two models were evaluated for the role of the charged pion exchange between nucleons and double-Delta excitation combined with intermediate rho-meson production. Differential cross sections as a function of the e(+)e(-) invariant mass and of the angles of the virtual photon, proton and electrons provide valuable constraints and encourage further investigations on both experimental and theoretical sides.

引用

页数：12