https://doi.org/10.1140/epjc/s10052-012-2168-x
Regular Article - Experimental Physics
Measurement of prompt hadron production ratios in pp collisions at 
1
CERN, 1211, Geneva 23, Switzerland
2
Centro Brasileiro de Pesquisas Físicas (CBPF), Rio de Janeiro, Brazil
3
Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil
4
Center for High Energy Physics, Tsinghua University, Beijing, China
5
LAPP, Université de Savoie, CNRS/IN2P3, Annecy-Le-Vieux, France
6
Clermont Université, Université Blaise Pascal, CNRS/IN2P3, LPC, Clermont-Ferrand, France
7
CPPM, Aix-Marseille Université, CNRS/IN2P3, Marseille, France
8
LAL, Université Paris-Sud, CNRS/IN2P3, Orsay, France
9
LPNHE, Université Pierre et Marie Curie, Université Paris Diderot, CNRS/IN2P3, Paris, France
10
Fakultät Physik, Technische Universität Dortmund, Dortmund, Germany
11
Max-Planck-Institut für Kernphysik (MPIK), Heidelberg, Germany
12
Physikalisches Institut, Ruprecht-Karls-Universität Heidelberg, Heidelberg, Germany
13
School of Physics, University College Dublin, Dublin, Ireland
14
Sezione INFN di Bari, Bari, Italy
15
Sezione INFN di Bologna, Bologna, Italy
16
Sezione INFN di Cagliari, Cagliari, Italy
17
Sezione INFN di Ferrara, Ferrara, Italy
18
Sezione INFN di Firenze, Firenze, Italy
19
Laboratori Nazionali dell’INFN di Frascati, Frascati, Italy
20
Sezione INFN di Genova, Genova, Italy
21
Sezione INFN di Milano Bicocca, Milano, Italy
22
Sezione INFN di Roma Tor Vergata, Roma, Italy
23
Sezione INFN di Roma La Sapienza, Roma, Italy
24
Henryk Niewodniczanski Institute of Nuclear Physics Polish Academy of Sciences, Kraków, Poland
25
AGH University of Science and Technology, Kraków, Poland
26
Soltan Institute for Nuclear Studies, Warsaw, Poland
27
Horia Hulubei National Institute of Physics and Nuclear Engineering, Bucharest-Magurele, Romania
28
Petersburg Nuclear Physics Institute (PNPI), Gatchina, Russia
29
Institute of Theoretical and Experimental Physics (ITEP), Moscow, Russia
30
Institute of Nuclear Physics, Moscow State University (SINP MSU), Moscow, Russia
31
Institute for Nuclear Research of the Russian Academy of Sciences (INR RAN), Moscow, Russia
32
Budker Institute of Nuclear Physics (SB RAS) and Novosibirsk State University, Novosibirsk, Russia
33
Institute for High Energy Physics (IHEP), Protvino, Russia
34
Universitat de Barcelona, Barcelona, Spain
35
Universidad de Santiago de Compostela, Santiago de Compostela, Spain
36
European Organization for Nuclear Research (CERN), Geneva, Switzerland
37
Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
38
Physik-Institut, Universität Zürich, Zürich, Switzerland
39
Nikhef National Institute for Subatomic Physics, Amsterdam, The Netherlands
40
Nikhef National Institute for Subatomic Physics and VU University Amsterdam, Amsterdam, The Netherlands
41
NSC Kharkiv Institute of Physics and Technology (NSC KIPT), Kharkiv, Ukraine
42
Institute for Nuclear Research of the National Academy of Sciences (KINR), Kyiv, Ukraine
43
University of Birmingham, Birmingham, UK
44
H.H. Wills Physics Laboratory, University of Bristol, Bristol, UK
45
Cavendish Laboratory, University of Cambridge, Cambridge, UK
46
Department of Physics, University of Warwick, Coventry, UK
47
STFC Rutherford Appleton Laboratory, Didcot, UK
48
School of Physics and Astronomy, University of Edinburgh, Edinburgh, UK
49
School of Physics and Astronomy, University of Glasgow, Glasgow, UK
50
Oliver Lodge Laboratory, University of Liverpool, Liverpool, UK
51
Imperial College London, London, UK
52
School of Physics and Astronomy, University of Manchester, Manchester, UK
53
Department of Physics, University of Oxford, Oxford, UK
54
Syracuse University, Syracuse, NY, USA
55
Pontifícia Universidade Católica do Rio de Janeiro (PUC-Rio), Rio de Janeiro, Brazil
56
Institut für Physik, Universität Rostock, Rostock, Germany
* e-mail: guy.wilkinson@cern.ch
Received:
22
June
2012
Revised:
16
August
2012
Published online:
5
October
2012
The charged-particle production ratios 
, K
−/K
+, π
−/π
+, 
, (K
++K
−)/(π
++π
−) and 
are measured with the LHCb detector using 0.3 nb−1 of pp collisions delivered by the LHC at 
and 1.8 nb−1 at 
. The measurements are performed as a function of transverse momentum p
T and pseudorapidity η. The production ratios are compared to the predictions of several Monte Carlo generator settings, none of which are able to describe adequately all observables. The ratio is also considered as a function of rapidity loss, Δy≡y
beam−y, and is used to constrain models of baryon transport.
© Springer-Verlag Berlin Heidelberg and Società Italiana di Fisica, 2012
