https://doi.org/10.1140/epja/i2015-15107-y
Regular Article - Experimental Physics
Experimental access to Transition Distribution Amplitudes with the P̄ANDA experiment at FAIR
1
Physics Department, Aligarth Muslim University, Aligarth, India
2
Universität Basel, Basel, Switzerland
3
Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, China
4
Universität Bochum I. Institut für Experimentalphysik, Bochum, Germany
5
Rheinische Friedrich-Wilhelms-Universität Bonn, Bonn, Germany
6
Università di Brescia, Brescia, Italy
7
Institutul National de C&D pentru Fizica si Inginerie Nucleara “Horia Hulubei”, Bukarest-Magurele, Romania
8
P.D. Patel Institute of Applied Science, Department of Physical Sciences, Changa, India
9
IIT, Illinois Institute of Technology, Chicago, USA
10
Institute of Applied Informatics, University of Technology, Cracow, Poland
11
AGH, University of Science and Technology, Cracow, Poland
12
Institute of Nuclear Physics PAN, IFJ, Cracow, Poland
13
Instytut Fizyki, Uniwersytet Jagiellonski, Cracow, Poland
14
Facility for Antiproton and Ion Research in Europe, FAIR, Darmstadt, Germany
15
GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany
16
Veksler-Baldin Laboratory of High Energies (VBLHE), Joint Institute for Nuclear Research, Dubna, Russia
17
University of Edinburgh, Edinburgh, UK
18
Friedrich Alexander Universität Erlangen-Nürnberg, Erlangen-Nürnberg, Germany
19
Northwestern University, Evanston, USA
20
Università di Ferrara and INFN Sezione di Ferrara, Ferrara, Italy
21
Frankfurt Institute for Advanced Studies, Frankfurt, Germany
22
Institut für Kernphysik, Goethe Universität, Frankfurt, Germany
23
Laboratori Nazionali di Frascati, INFN, Frascati, Italy
24
Sezione di Genova, INFN, Genova, Italy
25
Justus Liebig-Universität Gießen II. Physikalisches Institut, Gießen, Germany
26
University of Glasgow, Glasgow, UK
27
Birla Institute of Technology and Science - Pilani, K.K. Birla Goa Campus, Goa, India
28
KVI - Center for Advanced Radiation Technology, University of Groningen, Groningen, The Netherlands
29
Physics Department, Gauhati University, Guwahati, India
30
School of Science, Indian Institute of Technology Indore, Indore, India
31
Fachhochschule Südwestfalen, Iserlohn, Germany
32
Institut für Kernphysik, Forschungszentrum Jülich, Jülich, Germany
33
Institute of Modern Physics, Chinese Academy of Science, Lanzhou, China
34
INFN Laboratori Nazionali di Legnaro, Legnaro, Italy
35
Department of Physics, Lunds Universitet, Lund, Sweden
36
Institut für Kernphysik, Johannes Gutenberg-Universität, Mainz, Germany
37
Research Institute for Nuclear Problems, Belarus State University, Minsk, Belarus
38
Institute for Theoretical and Experimental Physics, Moscow, Russia
39
Moscow Power Engineering Institute, Moscow, Russia
40
Technische Universität München, München, Germany
41
Westfälische Wilhelms-Universität Münster, Münster, Germany
42
Department of Physics, Indian Institute of Technology Bombay, Mumbai, India
43
Nuclear Physics Division, Bhabha Atomic Research Centre, Mumbai, India
44
Suranaree University of Technology, Nakhon Ratchasima, Thailand
45
Budker Institute of Nuclear Physics of Russian Academy of Science, Novosibirsk, Russia
46
Novosibirsk State Technical University, Novosibirsk, Russia
47
Novosibirsk State University, Novosibirsk, Russia
48
Institut de Physique Nucléaire d’Orsay (UMR8608), CNRS/IN2P3 and Université Paris-Sud, Orsay, France
49
Dipartimento di Fisica, Università di Pavia, Pavia, Italy
50
Institute for High Energy Physics, Protvino, Russia
51
School of Physics, University of Sidney, Sidney, Australia
52
Kungliga Tekniska Högskolan, Stockholm, Sweden
53
Stockholms Universitet, Stockholm, Sweden
54
Petersburg Nuclear Physics Institute of Russian Academy of Science, Gatchina, St. Petersburg, Russia
55
Applied Physics Department, Sardar Vallabhbhai National Institute of Technology, Surat, India
56
Department of Physics, Veer Narmand South Gujarat University, Surat, India
57
Università di Torino and INFN Sezione di Torino, Torino, Italy
58
Sezione di Torino, INFN, Torino, Italy
59
Politecnico di Torino and INFN Sezione di Torino, Torino, Italy
60
Università di Trieste and INFN Sezione di Trieste, Trieste, Italy
61
Universität Tübingen, Tübingen, Germany
62
The Svedberg Laboratory, Uppsala, Sweden
63
Institutionen för Strålningsvetenskap, Uppsala Universitet, Uppsala, Sweden
64
Instituto de Física Corpuscular (IFIC), Universidad de Valencia - CSIC, Paterna, Valencia, Spain
65
Physics Department, Sardar Patel University, Vallabh Vidynagar, India
66
National Centre for Nuclear Research, Warsaw, Poland
67
Stefan Meyer Institut für Subatomare Physik, Österreichische Akademie der Wissenschaften, Wien, Austria
68
IFPA, département AGO, Université de Liège, Liège, Belgium
* e-mail: zambrana@kph.uni-mainz.de
Received:
4
September
2014
Revised:
21
May
2015
Accepted:
6
August
2015
Published online:
28
August
2015
Baryon-to-meson Transition Distribution Amplitudes (TDAs) encoding valuable new information on hadron structure appear as building blocks in the collinear factorized description for several types of hard exclusive reactions. In this paper, we address the possibility of accessing nucleon-to-pion (πN) TDAs from 
reaction with the future P̄ANDA detector at the FAIR facility. At high center-of-mass energy and high invariant mass squared of the lepton pair q
2, the amplitude of the signal channel admits a QCD factorized description in terms of πN TDAs and nucleon Distribution Amplitudes (DAs) in the forward and backward kinematic regimes. Assuming the validity of this factorized description, we perform feasibility studies for measuring with the P̄ANDA detector. Detailed simulations on signal reconstruction efficiency as well as on rejection of the most severe background channel, i.e.
were performed for the center-of-mass energy squared s = 5 GeV2 and s = 10 GeV2, in the kinematic regions 3.0 < q
2 < 4.3 GeV2 and 5 < q
2 GeV2, respectively, with a neutral pion scattered in the forward or backward cone 
in the proton-antiproton center-of-mass frame. Results of the simulation show that the particle identification capabilities of the P̄ANDA detector will allow to achieve a background rejection factor of 5 · 107 (1 · 107) at low (high) q
2 for s = 5 GeV2, and of 1 · 108 (6 · 106) at low (high) q
2 for s = 10 GeV2, while keeping the signal reconstruction efficiency at around 40%. At both energies, a clean lepton signal can be reconstructed with the expected statistics corresponding to 2 fb−1 of integrated luminosity. The cross sections obtained from the simulations are used to show that a test of QCD collinear factorization can be done at the lowest order by measuring scaling laws and angular distributions. The future measurement of the signal channel cross section with P̄ANDA will provide a new test of the perturbative QCD description of a novel class of hard exclusive reactions and will open the possibility of experimentally accessing π TDAs.
© SIF, Springer-Verlag Berlin Heidelberg, 2015
