@article{4b8a9ea1922e4d65ba94825b3abd7f57,

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)2<Q2<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 {Grosse Perdekamp}, M. and N. Makins and Peng, {J. C.} and C. Riedl",

note = "Funding Information: Supported by the DFG Research Training Group Programmes 1102 and 2044 (Germany). Publisher Copyright: {\textcopyright} 2018 The Author(s)",

year = "2018",

month = jun,

day = "10",

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

language = "English (US)",

volume = "781",

pages = "464--472",

journal = "Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics",

issn = "0370-2693",

publisher = "Elsevier",

}