https://doi.org/10.1140/epjc/s10052-009-1143-7
Letter
Measurement of the longitudinal spin transfer to Λ and
hyperons in polarised muon DIS
1
Fakultät für Physik, Universität Bielefeld, 33501, Bielefeld, Germany
2
Institut für Experimentalphysik, Universität Bochum, 44780, Bochum, Germany
3
Helmholtz-Institut für Strahlen- und Kernphysik, Universität Bonn, 53115, Bonn, Germany
4
Physikalisches Institut, Universität Bonn, 53115, Bonn, Germany
5
AS CR, Institute of Scientific Instruments, 61264, Brno, Czech Republic
6
Burdwan University, Burdwan, 713104, India
7
Matrivani Institute of Experimental Research & Education, Calcutta, 700 030, India
8
Joint Institute for Nuclear Research, 141980, Dubna, Moscow Region, Russia
9
Physikalisches Institut, Universität Erlangen–Nürnberg, 91054, Erlangen, Germany
10
Physikalisches Institut, Universität Freiburg, 79104, Freiburg, Germany
11
CERN, 1211, Geneva 23, Switzerland
12
Technical University in Liberec, 46117, Liberec, Czech Republic
13
LIP, 1000-149, Lisbon, Portugal
14
Institut für Kernphysik, Universität Mainz, 55099, Mainz, Germany
15
University of Miyazaki, Miyazaki, 889-2192, Japan
16
Lebedev Physical Institute, 119991, Moscow, Russia
17
Department für Physik, Ludwig-Maximilians-Universität München, 80799, Munich, Germany
18
Physik Department, Technische Universität München, 85748, Garching, Germany
19
Nagoya University, 464, Nagoya, Japan
20
Faculty of Mathematics and Physics, Charles University, 18000, Prague, Czech Republic
21
Czech Technical University in Prague, 16636, Prague, Czech Republic
22
Institute for High Energy Physics, State Research Center of the Russian Federation, 142281, Protvino, Russia
23
CEA DAPNIA/SPhN Saclay, 91191, Gif-sur-Yvette, France
24
School of Physics and Astronomy, Tel Aviv University, 69978, Tel Aviv, Israel
25
Trieste Section of INFN, 34127, Trieste, Italy
26
Department of Physics and Trieste Section of INFN, University of Trieste, 34127, Trieste, Italy
27
Abdus Salam ICTP and Trieste Section of INFN, 34127, Trieste, Italy
28
Department of Physics and Torino Section of INFN, University of Turin, 10125, Turin, Italy
29
Torino Section of INFN, 10125, Turin, Italy
30
1500 Alessandria, and Torino Section of INFN, University of Eastern Piedmont, 10125, Turin, Italy
31
Sołtan Institute for Nuclear Studies and University of Warsaw, 00-681, Warsaw, Poland
32
Institute of Radioelectronics, Warsaw University of Technology, 00-665, Warsaw, Poland
33
Yamagata University, Yamagata, 992-8510, Japan
* e-mail: Gerhard.Mallot@cern.ch
Received:
3
July
2009
Published online:
7
October
2009
The longitudinal polarisation transfer from muons to Λ and
hyperons,
, has been studied in deep-inelastic scattering off an unpolarised isoscalar target at the COMPASS experiment at CERN. The spin transfers to Λ and
produced in the current fragmentation region exhibit different behaviours as a function of x and x
F
. The measured x and x
F
dependences of D
LL
Λ
are compatible with zero, while
tends to increase with x
F
, reaching values of 0.4–0.5. The resulting average values are D
LL
Λ
= −0.012±0.047±0.024 and
= 0.249±0.056±0.049. These results are discussed in the frame of recent model calculations.
PACS: 13.60.Rj – / 13.87.Fh – / 13.88.+e – / 14.20.Jn –
© Springer-Verlag , 2009