Proton transverse-spin azimuthal asymmetries are extracted from the COMPASS 2010 semi-inclusive hadron measurements in deep inelastic muon-nucleon scattering in those four regions of the photon virtuality $Q^2$, which correspond to the four regions of the di-muon mass $\sqrt{Q^2}$ used in the ongoing analysis of the COMPASS Drell-Yan measurements. This allows for a future direct comparison of the nucleon transverse-momentum-dependent parton distribution functions extracted from these two alternative measurements. Various two-dimensional kinematic dependences are presented for the azimuthal asymmetries induced by the Sivers transverse-momentum-dependent parton distribution function. The integrated Sivers asymmetries are found to be positive with an accuracy that appears to be sufficient to test the sign change of the Sivers function predicted by Quantum Chromodynamics.

Compass

Drell–Yan process

10.1016/j.physletb.2017.04.042

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Citations (55)

Aberration integrals for the low-voltage foil corrector

Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment (2003)

R.H. van Aken Michal Lenc J. Barth

Chromatic aberration

Optical aberration

Derivative (finance)

10.1016/j.nima.2003.11.157

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Citations (10)

High-statistics measurement of Collins and Sivers asymmetries for transversely polarised deuterons

arXiv (Cornell University) (2024)

G. D. Alexeev M. Alexeev C. Alice A. Amoroso V. Andrieux

New results are presented on a high-statistics measurement of Collins and Sivers asymmetries of charged hadrons produced in deep inelastic scattering of muons on a transversely polarised $^6$LiD target. The data were taken in 2022 with the COMPASS spectrometer using the 160 \gevv\ muon beam at CERN, balancing the existing data on transversely polarised proton targets. The first results from about two-thirds of the new data have total uncertainties smaller by up to a factor of three compared to the previous deuteron measurements. Using all the COMPASS proton and deuteron results, both the transversity and the Sivers distribution functions of the $u$ and $d$ quark, as well as the tensor charge in the measured $x$-range are extracted. In particular, the accuracy of the $d$ quark results is significantly improved.

Compass

10.48550/arxiv.2401.00309

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The deuteron spin-dependent structure function g1d and its first moment

Physics Letters B (2007)

V. Alexakhin Yu. Alexandrov G. D. Alexeev M. Alexeev A. Amoroso

10.1016/j.physletb.2006.12.076

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Citations (277)

II – Experimental investigation of transverse spin asymmetries in μ-p SIDIS processes: Sivers asymmetries

Physics Letters B (2012)

C. Adolph M.G. Alekseev V.Yu. Alexakhin Yu. Alexandrov G. D. Alexeev

The COMPASS Collaboration at CERN has measured the transverse spin azimuthal asymmetry of charged hadrons produced in semi-inclusive deep inelastic scattering using a 160 GeV μ+ beam and a transversely polarised NH3 target. The Sivers asymmetry of the proton has been extracted in the Bjorken x range 0.0030.03. The asymmetry is different from zero and positive also in the low x region, where sea-quarks dominate. The kinematic dependence of the asymmetry has also been investigated and results are given for various intervals of hadron and virtual photon fractional energy. In contrast to the case of the Collins asymmetry, the results on the Sivers asymmetry suggest a strong dependence on the four-momentum transfer to the nucleon, in agreement with the most recent calculations.

Compass

10.1016/j.physletb.2012.09.056

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Citations (145)

Measurement of the cross section for hard exclusive $\pi^0$ leptoproduction

HAL (Le Centre pour la Communication Scientifique Directe) (2019)

M. Alexeev G. D. Alexeev A. Amoroso V. Andrieux Н. Анфимов

Section (typography)

Source

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Odd and even partial waves of ηπ − and η π − in π − p → η () π − p

C. Adolph A. Amoroso V. Andrieux В. Аносов A. Austregesilo

Source

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Engineering constraints and computer-aided optimization of electrostatic lens systems

Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment (1990)

H. Steen J. Barth J.P. Adriaanse

Electrostatic lens

10.1016/0168-9002(90)90639-n

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Citations (8)

Transverse-momentum-dependent multiplicities of charged hadrons in muon-deuteron deep inelastic scattering

Physical review. D/Physical review. D. (2018)

M. Aghasyan M. Alexeev G.D. Alexeev A. Amoroso V. Andrieux

A semi-inclusive measurement of charged hadron multiplicities in deep inelastic muon scattering off an isoscalar target was performed using data collected by the COMPASS Collaboration at CERN. The following kinematic domain is covered by the data: photon virtuality ${Q}^{2}>1\text{ }\text{ }(\mathrm{GeV}/c{)}^{2}$, invariant mass of the hadronic system $W>5\text{ }\text{ }\mathrm{GeV}/{c}^{2}$, Bjorken scaling variable in the range $0.003

Virtual particle

Perturbative QCD

10.1103/physrevd.97.032006

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Citations (59)