Single-spin asymmetries in semi-inclusive deep-inelastic scattering on a transversely polarized hydrogen target.
Single-spin asymmetries for semi-inclusive electroproduction of charged pions in deep-inelastic scattering of positrons are measured for the first time with transverse target polarization. The asymmetry depends on the azimuthal angles of both the pion (phi) and the target spin axis (phi(S)) about the virtual-photon direction and relative to the lepton scattering plane. The extracted Fourier component sin((phi+phi(S))(pi)(UT) is a signal of the previously unmeasured quark transversity distribution, in conjunction with the Collins fragmentation function, also unknown. The component sin((phi-phi(S)(pi)(UT) arises from a correlation between the transverse polarization of the target nucleon and the intrinsic transverse momentum of quarks, as represented by the previously unmeasured Sivers distribution function. Evidence for both signals is observed, but the Sivers asymmetry may be affected by exclusive vector meson production.
Airapetian
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Randall Laboratory of Physics, University of Michigan, Ann Arbor, MI 48109-1120, USA.
Akopov
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Akopov
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Amarian
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Andrus
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Aschenauer
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Augustyniak
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Avakian
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Avetissian
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Avetissian
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Bacchetta
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Bailey
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Balin
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Beckmann
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Belostotski
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Bianchi
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Blok
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Böttcher
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Borissov
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Borysenko
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Bouwhuis
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Brüll
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Bryzgalov
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Capitani
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Cappiluppi
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Chen
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Ciullo
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Contalbrigo
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Dalpiaz
P F
PF
Leo
R De
RD
Demey
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Nardo
L De
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Sanctis
E De
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Devitsin
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Nezza
P Di
PD
Düren
M
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Ehrenfried
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Elalaoui-Moulay
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Elbakian
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Ellinghaus
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Elschenbroich
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Fabbri
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Fantoni
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Fechtchenko
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Felawka
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Frullani
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Gapienko
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Gapienko
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Garibaldi
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Garrow
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Gavrilov
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Gharibyan
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Grebeniouk
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Gregor
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Hadjidakis
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Hafidi
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Hartig
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Hasch
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Henoch
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Hesselink
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Hillenbrand
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Hoek
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Holler
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Hommez
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Hristova
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Iarygin
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Ilyichev
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Ivanilov
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Izotov
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Jackson
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Jgoun
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Kaiser
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Kinney
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Kisselev
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Kobayashi
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Kopytin
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Korotkov
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Kozlov
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Krauss
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Krivokhijine
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Lagamba
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Lapikás
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Laziev
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Lenisa
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Liebing
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Linden-Levy
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Lorenzon
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Lu
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Lu
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Lu
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Ma
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Maiheu
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Makins
N C R
NC
Mao
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Marianski
B
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Marukyan
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Masoli
F
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Mexner
V
V
Meyners
N
N
Michler
T
T
Mikloukho
O
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Miller
C A
CA
Miyachi
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Muccifora
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Nagaitsev
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Nappi
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Naryshkin
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Nass
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Negodaev
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Nowak
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Oganessyan
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Ohsuga
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Osborne
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Pickert
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Potterveld
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Raithel
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Reggiani
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Reimer
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Reischl
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Reolon
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Riedl
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Rith
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Rosner
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Rostomyan
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Rubacek
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Rubin
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Ryckbosch
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Salomatin
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Sanjiev
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Savin
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Schäfer
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Schill
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Schnell
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Schüler
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Seele
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Seidl
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Seitz
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Shanidze
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Shearer
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Shibata
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Shutov
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Sinram
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Sommer
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Stancari
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Statera
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Steffens
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Steijger
J J M
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Stenzel
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Stewart
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Stinzing
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Tait
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Tanaka
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Taroian
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Tchuiko
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Terkulov
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Trzcinski
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Tytgat
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Vandenbroucke
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van der Nat
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van der Steenhoven
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van Haarlem
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Vetterli
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Vikhrov
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Vincter
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Vogel
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Volmer
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Wang
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Wendland
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Wilbert
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Smit
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Ye
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Yen
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Zihlmann
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Zupranski
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