Measurement of the longitudinal spin transfer to Λ and hyperons in polarised muon DIS

M. Alekseev; V. Yu. Alexakhin; Yu. Alexandrov; G. D. Alexeev; A. Amoroso; A. Austregesilo; B. Badełek; F. Balestra; J. Ball; J. Barth; G. Baum; Y. Bedfer; J. Bernhard; R. Bertini; M. Bettinelli; R. Birsa; J. Bisplinghoff; P. Bordalo; F. Bradamante; A. Bravar; A. Bressan; G. Brona; E. Burtin; M. P. Bussa; A. Chapiro; M. Chiosso; S. U. Chung; A. Cicuttin; M. Colantoni; M. L. Crespo; S. Dalla Torre; T. Dafni; S. Das; S. S. Dasgupta; O. Yu. Denisov; L. Dhara; V. Diaz; A. M. Dinkelbach; S. V. Donskov; N. Doshita; V. Duic; W. Dünnweber; A. Efremov; P. D. Eversheim; W. Eyrich; M. Faessler; A. Ferrero; M. Finger; M. Finger; H. Fischer; C. Franco; J. M. Friedrich; R. Garfagnini; F. Gautheron; O. P. Gavrichtchouk; R. Gazda; S. Gerassimov; R. Geyer; M. Giorgi; B. Gobbo; S. Goertz; S. Grabmüller; O. A. Grajek; A. Grasso; B. Grube; R. Gushterski; A. Guskov; F. Haas; D. von Harrach; T. Hasegawa; J. Heckmann; F. H. Heinsius; M. Hermann; R. Hermann; F. Herrmann; C. Heß; F. Hinterberger; N. Horikawa; Ch. Höppner; N. d’Hose; C. Ilgner; S. Ishimoto; O. Ivanov; Yu. Ivanshin; B. Iven; T. Iwata; R. Jahn; P. Jasinski; G. Jegou; R. Joosten; E. Kabuß; D. Kang; B. Ketzer; G. V. Khaustov; Yu. A. Khokhlov; Yu. Kisselev; F. Klein; K. Klimaszewski; S. Koblitz; J. H. Koivuniemi; V. N. Kolosov; E. V. Komissarov; K. Kondo; K. Königsmann; R. Konopka; I. Konorov; V. F. Konstantinov; A. Korzenev; A. M. Kotzinian; O. Kouznetsov; K. Kowalik; M. Krämer; A. Kral; Z. V. Kroumchtein; R. Kuhn; F. Kunne; K. Kurek; J. M. Le Goff; A. A. Lednev; A. Lehmann; S. Levorato; J. Lichtenstadt; T. Liska; A. Maggiora; M. Maggiora; A. Magnon; G. K. Mallot; A. Mann; C. Marchand; J. Marroncle; A. Martin; J. Marzec; F. Massmann; T. Matsuda; A. N. Maximov; W. Meyer; T. Michigami; Yu. V. Mikhailov; M. A. Moinester; A. Mutter; A. Nagaytsev; T. Nagel; J. Nassalski; S. Negrini; F. Nerling; S. Neubert; D. Neyret; V. I. Nikolaenko; A. G. Olshevsky; M. Ostrick; A. Padee; R. Panknin; D. Panzieri; B. Parsamyan; S. Paul; B. Pawlukiewicz-Kaminska; E. Perevalova; G. Pesaro; D. V. Peshekhonov; G. Piragino; S. Platchkov; J. Pochodzalla; J. Polak; V. A. Polyakov; G. Pontecorvo; J. Pretz; C. Quintans; J.-F. Rajotte; S. Ramos; V. Rapatsky; G. Reicherz; D. Reggiani; A. Richter; F. Robinet; E. Rocco; E. Rondio; D. I. Ryabchikov; V. D. Samoylenko; A. Sandacz; H. Santos; M. G. Sapozhnikov; S. Sarkar; G. Sbrizzai; P. Schiavon; C. Schill; L. Schmitt; W. Schröder; O. Yu. Shevchenko; H.-W. Siebert; L. Silva; L. Sinha; A. N. Sissakian; M. Slunecka; G. I. Smirnov; S. Sosio; F. Sozzi; A. Srnka; M. Stolarski; M. Sulc; R. Sulej; S. Takekawa; S. Tessaro; F. Tessarotto; A. Teufel; L. G. Tkatchev; G. Venugopal; M. Virius; N. V. Vlassov; A. Vossen; Q. Weitzel; R. Windmolders; W. Wiślicki; H. Wollny; K. Zaremba; E. Zemlyanichkina; M. Ziembicki; J. Zhao; N. Zhuravlev; A. Zvyagin

doi:10.1140/epjc/s10052-009-1143-7

2024 Impact factor 4.8

Particles and Fields

Open Access

Eur. Phys. J. C (2009) 64: 171-179
https://doi.org/10.1140/epjc/s10052-009-1143-7

Letter

Measurement of the longitudinal spin transfer to Λ and $\bar{\varLambda}$ hyperons in polarised muon DIS

M. Alekseev³⁰, V. Yu. Alexakhin⁸, Yu. Alexandrov¹⁶, G. D. Alexeev⁸, A. Amoroso²⁸, A. Austregesilo¹¹^,18, B. Badełek³¹, F. Balestra²⁸, J. Ball²³, J. Barth⁴, G. Baum¹, Y. Bedfer²³, J. Bernhard¹⁴, R. Bertini²⁸, M. Bettinelli¹⁷, R. Birsa²⁵, J. Bisplinghoff³, P. Bordalo¹³, F. Bradamante²⁶, A. Bravar²⁵, A. Bressan²⁶, G. Brona³¹, E. Burtin²³, M. P. Bussa²⁸, A. Chapiro²⁷, M. Chiosso²⁸, S. U. Chung¹⁸, A. Cicuttin²⁵^,27, M. Colantoni²⁹, M. L. Crespo²⁵^,27, S. Dalla Torre²⁵, T. Dafni²³, S. Das⁷, S. S. Dasgupta⁶, O. Yu. Denisov²⁹, L. Dhara⁷, V. Diaz²⁵^,27, A. M. Dinkelbach¹⁸, S. V. Donskov²², N. Doshita²^,33, V. Duic²⁶, W. Dünnweber¹⁷, A. Efremov⁸, P. D. Eversheim³, W. Eyrich⁹, M. Faessler¹⁷, A. Ferrero¹¹^,28, M. Finger²⁰, M. Finger⁸, H. Fischer¹⁰, C. Franco¹³, J. M. Friedrich¹⁸, R. Garfagnini²⁸, F. Gautheron¹, O. P. Gavrichtchouk⁸, R. Gazda³¹, S. Gerassimov¹⁶^,18, R. Geyer¹⁷, M. Giorgi²⁶, B. Gobbo²⁵, S. Goertz²^,4, S. Grabmüller¹⁸, O. A. Grajek³¹, A. Grasso²⁸, B. Grube¹⁸, R. Gushterski⁸, A. Guskov⁸, F. Haas¹⁸, D. von Harrach¹⁴, T. Hasegawa¹⁵, J. Heckmann², F. H. Heinsius¹⁰, M. Hermann³, R. Hermann¹⁴, F. Herrmann¹⁰, C. Heß², F. Hinterberger³, N. Horikawa¹⁹, Ch. Höppner¹⁸, N. d’Hose²³, C. Ilgner¹¹^,17, S. Ishimoto¹⁹, O. Ivanov⁸, Yu. Ivanshin⁸, B. Iven³, T. Iwata³³, R. Jahn³, P. Jasinski¹⁴, G. Jegou²³, R. Joosten³, E. Kabuß¹⁴, D. Kang¹⁰, B. Ketzer¹⁸, G. V. Khaustov²², Yu. A. Khokhlov²², Yu. Kisselev¹^,2, F. Klein⁴, K. Klimaszewski³¹, S. Koblitz¹⁴, J. H. Koivuniemi², V. N. Kolosov²², E. V. Komissarov⁸, K. Kondo²^,33, K. Königsmann¹⁰, R. Konopka¹⁸, I. Konorov¹⁶^,18, V. F. Konstantinov²², A. Korzenev¹⁴, A. M. Kotzinian⁸, O. Kouznetsov²³^,8, K. Kowalik²³^,31, M. Krämer¹⁸, A. Kral²¹, Z. V. Kroumchtein⁸, R. Kuhn¹⁸, F. Kunne²³, K. Kurek³¹, J. M. Le Goff²³, A. A. Lednev²², A. Lehmann⁹, S. Levorato²⁶, J. Lichtenstadt²⁴, T. Liska²¹, A. Maggiora²⁹, M. Maggiora²⁸, A. Magnon²³, G. K. Mallot¹¹^*, A. Mann¹⁸, C. Marchand²³, J. Marroncle²³, A. Martin²⁶, J. Marzec³², F. Massmann³, T. Matsuda¹⁵, A. N. Maximov⁸, W. Meyer², T. Michigami³³, Yu. V. Mikhailov²², M. A. Moinester²⁴, A. Mutter¹⁰^,14, A. Nagaytsev⁸, T. Nagel¹⁸, J. Nassalski³¹, S. Negrini³, F. Nerling¹⁰, S. Neubert¹⁸, D. Neyret²³, V. I. Nikolaenko²², A. G. Olshevsky⁸, M. Ostrick¹⁴^,4, A. Padee³², R. Panknin⁴, D. Panzieri³⁰, B. Parsamyan²⁸, S. Paul¹⁸, B. Pawlukiewicz-Kaminska³¹, E. Perevalova⁸, G. Pesaro²⁶, D. V. Peshekhonov⁸, G. Piragino²⁸, S. Platchkov²³, J. Pochodzalla¹⁴, J. Polak¹²^,26, V. A. Polyakov²², G. Pontecorvo⁸, J. Pretz⁴, C. Quintans¹³, J.-F. Rajotte¹⁷, S. Ramos¹³, V. Rapatsky⁸, G. Reicherz², D. Reggiani¹¹, A. Richter⁹, F. Robinet²³, E. Rocco²⁸, E. Rondio³¹, D. I. Ryabchikov²², V. D. Samoylenko²², A. Sandacz³¹, H. Santos¹³, M. G. Sapozhnikov⁸, S. Sarkar⁷, G. Sbrizzai²⁶, P. Schiavon²⁶, C. Schill¹⁰, L. Schmitt¹⁸, W. Schröder⁹, O. Yu. Shevchenko⁸, H.-W. Siebert¹⁴, L. Silva¹³, L. Sinha⁷, A. N. Sissakian⁸, M. Slunecka⁸, G. I. Smirnov⁸, S. Sosio²⁸, F. Sozzi²⁶, A. Srnka⁵, M. Stolarski¹¹^,31, M. Sulc¹², R. Sulej³², S. Takekawa²⁶, S. Tessaro²⁵, F. Tessarotto²⁵, A. Teufel⁹, L. G. Tkatchev⁸, G. Venugopal³, M. Virius²¹, N. V. Vlassov⁸, A. Vossen¹⁰, Q. Weitzel¹⁸, R. Windmolders⁴, W. Wiślicki³¹, H. Wollny¹⁰, K. Zaremba³², E. Zemlyanichkina⁸, M. Ziembicki³², J. Zhao¹⁴^,25, N. Zhuravlev⁸ and A. Zvyagin¹⁷

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

Abstract

The longitudinal polarisation transfer from muons to Λ and $\bar{\varLambda}$ hyperons, $D_{LL}^{\varLambda(\bar{\varLambda})}$ , has been studied in deep-inelastic scattering off an unpolarised isoscalar target at the COMPASS experiment at CERN. The spin transfers to Λ and $\bar{\varLambda}$ 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 $D_{LL}^{\bar{\varLambda}}$ 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 $D_{LL}^{\bar{\varLambda}}$ = 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 –

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