Longitudinal double-spin asymmetry A1                             p and spin-dependent structure function g1                             p of the proton at small values of x and Q2

COMPASS Collaboration

doi:10.1016/j.physletb.2018.03.044

Longitudinal double-spin asymmetry A₁ ^p and spin-dependent structure function g₁ ^p of the proton at small values of x and Q²

COMPASS Collaboration

Chair of Physics I

INFN- Sezione di Trieste
University of Torino
Joint Inst. for Nuclear Research
INFN Sez. di Torino
University Paris-Sud
University of Illinois at Urbana-Champaign
Czech Technical University in Prague
National Center for Nuclear Research (NCBJ)
Technical University of Munich
University of Aveiro
University of Warsaw
University of Bonn
European Organization for Nuclear Research
Johannes Gutenberg University
Charles University
LIP - Lisboa
Instituto Superior Técnico
University of Trieste Via A
University of Freiburg
Polytechnic University of Tomsk
Academia Sinica Taipei
Matrivani Institute of Experimental Research & Education
Pusan National University
Brookhaven National Laboratory
ICTP
Institute for High Energy Physics (IHEP)
Yamagata University
Warsaw Institute of Technology
Max-Planck-lnstitut für Kohlenforschung
P.N. Lebedev Physical Institute of the Russian Academy of Sciences
Nagoya University
Chubu University
National Central University
High Energy Accelerator Research Organization (KEK)
Moscow Institute of Physics and Technology
A.I. Alikhanyan National Science Laboratory (YerPhi)
National Kaohsiung Normal University
Tel Aviv University
University of Tübingen
University of Miyazaki
University of Eastern Piedmont
RWTH Aachen University
Uppsala University
Institute of Scientific Instruments of the Academy of Sciences of the Czech Republic
Technical University of Liberec

Research output: Contribution to journal › Article › peer-review

26 Scopus citations

Abstract

We present a precise measurement of the proton longitudinal double-spin asymmetry A₁ ^p and the proton spin-dependent structure function g₁ ^p at photon virtualities 0.006(GeV/c)²<Q²<1(GeV/c)² in the Bjorken x range of 4×10⁻⁵<x<4×10⁻². The results are based on data collected by the COMPASS Collaboration at CERN using muon beam energies of 160GeV and 200GeV. The statistical precision is more than tenfold better than that of the previous measurement in this region. In the whole range of x, the measured values of A₁ ^p and g₁ ^p are found to be positive. It is for the first time that spin effects are found at such low values of x.

Original language	English
Pages (from-to)	464-472
Number of pages	9
Journal	Physics Letters B
Volume	781
DOIs	https://doi.org/10.1016/j.physletb.2018.03.044
State	Published - 10 Jun 2018

Keywords

A
Inelastic muon scattering
Low Q
Low x
Spin structure function
g

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10.1016/j.physletb.2018.03.044

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@article{f01ac8190feb40a9b62c2faba2b44856,

title = "Longitudinal double-spin asymmetry A1 p and spin-dependent structure function g1 p of the proton at small values of x and Q2 ",

abstract = "We present a precise measurement of the proton longitudinal double-spin asymmetry A1 p and the proton spin-dependent structure function g1 p at photon virtualities 0.006(GeV/c)22<1(GeV/c)2 in the Bjorken x range of 4×10−5−2. The results are based on data collected by the COMPASS Collaboration at CERN using muon beam energies of 160GeV and 200GeV. The statistical precision is more than tenfold better than that of the previous measurement in this region. In the whole range of x, the measured values of A1 p and g1 p are found to be positive. It is for the first time that spin effects are found at such low values of x.",

keywords = "A, Inelastic muon scattering, Low Q, Low x, Spin structure function, g",

author = "\{COMPASS Collaboration\} and M. Aghasyan and Alexeev, \{M. G.\} and Alexeev, \{G. D.\} and A. Amoroso and V. Andrieux and Anfimov, \{N. V.\} and V. Anosov and A. Antoshkin and K. Augsten and W. Augustyniak and A. Austregesilo and Azevedo, \{C. D.R.\} and B. Bade{\l}ek and F. Balestra and M. Ball and J. Barth and R. Beck and Y. Bedfer and J. Bernhard and K. Bicker and Bielert, \{E. R.\} and R. Birsa and M. Bodlak and P. Bordalo and F. Bradamante and A. Bressan and M. B{\"u}chele and Burtsev, \{V. E.\} and L. Capozza and Chang, \{W. C.\} and C. Chatterjee and M. Chiosso and I. Choi and Chumakov, \{A. G.\} and Chung, \{S. U.\} and A. Cicuttin and Crespo, \{M. L.\} and \{Dalla Torre\}, S. and Dasgupta, \{S. S.\} and S. Dasgupta and Denisov, \{O. Yu\} and L. Dhara and Donskov, \{S. V.\} and N. Doshita and Ch Dreisbach and W. D{\"u}nnweber and Dusaev, \{R. R.\} and M. Dziewiecki and A. Efremov and S. Paul",

note = "Publisher Copyright: {\textcopyright} 2018 The Author(s)",

year = "2018",

month = jun,

day = "10",

doi = "10.1016/j.physletb.2018.03.044",

language = "English",

volume = "781",

pages = "464--472",

journal = "Physics Letters B",

issn = "0370-2693",

publisher = "Elsevier B.V.",

}

TY - JOUR

T1 - Longitudinal double-spin asymmetry A1 p and spin-dependent structure function g1 p of the proton at small values of x and Q2

AU - COMPASS Collaboration

AU - Aghasyan, M.

AU - Alexeev, M. G.

AU - Alexeev, G. D.

AU - Amoroso, A.

AU - Andrieux, V.

AU - Anfimov, N. V.

AU - Anosov, V.

AU - Antoshkin, A.

AU - Augsten, K.

AU - Augustyniak, W.

AU - Austregesilo, A.

AU - Azevedo, C. D.R.

AU - Badełek, B.

AU - Balestra, F.

AU - Ball, M.

AU - Barth, J.

AU - Beck, R.

AU - Bedfer, Y.

AU - Bernhard, J.

AU - Bicker, K.

AU - Bielert, E. R.

AU - Birsa, R.

AU - Bodlak, M.

AU - Bordalo, P.

AU - Bradamante, F.

AU - Bressan, A.

AU - Büchele, M.

AU - Burtsev, V. E.

AU - Capozza, L.

AU - Chang, W. C.

AU - Chatterjee, C.

AU - Chiosso, M.

AU - Choi, I.

AU - Chumakov, A. G.

AU - Chung, S. U.

AU - Cicuttin, A.

AU - Crespo, M. L.

AU - Dalla Torre, S.

AU - Dasgupta, S. S.

AU - Dasgupta, S.

AU - Denisov, O. Yu

AU - Dhara, L.

AU - Donskov, S. V.

AU - Doshita, N.

AU - Dreisbach, Ch

AU - Dünnweber, W.

AU - Dusaev, R. R.

AU - Dziewiecki, M.

AU - Efremov, A.

AU - Paul, S.

PY - 2018/6/10

Y1 - 2018/6/10

N2 - We present a precise measurement of the proton longitudinal double-spin asymmetry A1 p and the proton spin-dependent structure function g1 p at photon virtualities 0.006(GeV/c)22<1(GeV/c)2 in the Bjorken x range of 4×10−5−2. The results are based on data collected by the COMPASS Collaboration at CERN using muon beam energies of 160GeV and 200GeV. The statistical precision is more than tenfold better than that of the previous measurement in this region. In the whole range of x, the measured values of A1 p and g1 p are found to be positive. It is for the first time that spin effects are found at such low values of x.

AB - We present a precise measurement of the proton longitudinal double-spin asymmetry A1 p and the proton spin-dependent structure function g1 p at photon virtualities 0.006(GeV/c)22<1(GeV/c)2 in the Bjorken x range of 4×10−5−2. The results are based on data collected by the COMPASS Collaboration at CERN using muon beam energies of 160GeV and 200GeV. The statistical precision is more than tenfold better than that of the previous measurement in this region. In the whole range of x, the measured values of A1 p and g1 p are found to be positive. It is for the first time that spin effects are found at such low values of x.

KW - A

KW - Inelastic muon scattering

KW - Low Q

KW - Low x

KW - Spin structure function

KW - g

UR - https://www.scopus.com/pages/publications/85045934608

U2 - 10.1016/j.physletb.2018.03.044

DO - 10.1016/j.physletb.2018.03.044

M3 - Article

AN - SCOPUS:85045934608

SN - 0370-2693

VL - 781

SP - 464

EP - 472

JO - Physics Letters B

JF - Physics Letters B

ER -

Longitudinal double-spin asymmetry A₁ ^p and spin-dependent structure function g₁ ^p of the proton at small values of x and Q²

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Keywords

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