R. Heitz

Final COMPASS results on the transverse-spin-dependent azimuthal asymmetries in the pion-induced Drell-Yan process

G. D. Alexeev, M. Alexeev, C. Alice, A. Amoroso et autres

The COMPASS Collaboration performed measurements of the Drell-Yan process in 2015 and 2018 using a 190 GeV/c $π^{-}$ beam impinging on a transversely polarised ammonia target. Combining the data of both years, we present final results on the amplitudes of the five …

Exotic meson π1(1600) with JPC=1−+ and its decay into ρ(770)π

G. D. Alexeev, M. Alexeev, A. Amoroso, V. Andrieux et autres

We study the spin-exotic ${J}^{PC}={1}^{\ensuremath{-}+}$ amplitude in single-diffractive dissociation of $190\text{ }\text{ }\mathrm{GeV}/c$ pions into ${\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}$ using a hydrogen target and confirm the ${\ensuremath{\pi}}_{1}(1600)\ensuremath{\rightarrow}\ensuremath{\rho}(770)\ensuremath{\pi}$ amplitude, which interferes with a nonresonant ${1}^{\ensuremath{-}+}$ amplitude. We demonstrate that conflicting conclusions from previous studies on these …

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Probing transversity by measuring Λ polarisation in SIDIS

G. D. Alexeev, M.G. Alexeev, A. Amoroso, V. Andrieux et autres

Based on the observation of sizeable target-transverse-spin asymmetries in single-hadron and hadron-pair production in Semi-Inclusive measurements of Deep Inelastic Scattering (SIDIS), the chiral-odd transversity quark distribution functions h 1 q are nowadays well established. Several possible channels to access these functions were …

ru, it, us, ch, cz, pt, pl, de, fr, tw, in, jp, am (code pays fourni par la source)

Triangle Singularity as the Origin of the a1(1420)

G. D. Alexeev, M. Alexeev, A. Amoroso, V. Andrieux et autres

The COMPASS Collaboration experiment recently discovered a new isovector resonancelike signal with axial-vector quantum numbers, the a_{1}(1420), decaying to f_{0}(980)π. With a mass too close to and a width smaller than the axial-vector ground state a_{1}(1260), it was immediately interpreted as a …

ru, it, us, ch, cz, pl, pt, de, fr, tw, jp, il (code pays fourni par la source)

arXiv : The exotic meson $\pi_1(1600)$ with $J^{PC} = 1^{-+}$ and its decay into $\rho(770)\pi$

M. Alexeev, D. Eremeev, J. Giarra, M. Dano Hoffmann et autres

We study the spin-exotic $J^{PC} = 1^{-+}$ amplitude in single-diffractive dissociation of 190 GeV$/c$ pions into $\pi^-\pi^-\pi^+$ using a hydrogen target and confirm the $\pi_1(1600) \to \rho(770) \pi$ amplitude, which interferes with a nonresonant $1^{-+}$ amplitude. We demonstrate that conflicting conclusions from …

Probing transversity by measuring $\Lambda$ polarisation in SIDIS

M. Alexeev, J. Giarra, P. Sznajder, S.A. Mamon et autres

Based on the observation of sizeable target-transverse-spin asymmetries in single-hadron and hadron-pair production in Semi-Inclusive measurements of Deep Inelastic Scattering (SIDIS), the chiral-odd transversity quark distribution functions $h_1^q$ are nowadays well established. Several possible channels to access these functions were originally proposed. …

Spin density matrix elements in exclusive $$\omega $$ meson muoproduction

G. D. Alexeev, M. Alexeev, A. Amoroso, V. Andrieux et autres

Abstract We report on a measurement of Spin Density Matrix Elements (SDMEs) in hard exclusive $$\omega $$ ω meson muoproduction on the proton at COMPASS using 160 GeV/c polarised $$ \mu ^{+}$$ μ + and $$ \mu ^{-}$$ μ - beams impinging …

ru, it, us, ch, cz, pl, pt, de, fr, tw, jp (code pays fourni par la source)

Repeated Maximal Volitional Effort Contractions in Human Spinal Cord Injury: Initial Torque Increases and Reduced Fatigue

Michael D. Lewek, Christopher K. Thompson, T. George Hornby, R. Heitz

Substantial data indicate greater muscle fatigue in individuals with spinal cord injury (SCI) compared with healthy control subjects when tested by using electrical stimulation protocols. Few studies have investigated the extent of volitional fatigue in motor incomplete SCI.

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Spin Density Matrix Elements in Exclusive $ω$ Meson Muoproduction $^*$

M. Alexeev, G. D. Alexeev, A. Amoroso, V. Andrieux et autres

We report on a measurement of Spin Density Matrix Elements (SDMEs) in hard exclusive $ω$ meson muoproduction on the proton at COMPASS using 160 GeV/$c$ polarised $ μ^{+}$ and $ μ^{-}$ beams impinging on a liquid hydrogen target. The measurement covers the …

Antiproton over proton and K− over K+ multiplicity ratios at high z in DIS

G. D. Alexeev, M. Alexeev, A. Amoroso, V. Andrieux et autres

The antiparticle-over-particle multiplicity ratio is measured in deep-inelastic scattering for negatively and positively charged kaons and, for the first time, for antiprotons and protons. The data were obtained by the COMPASS Collaboration using a 160 GeV muon beam impinging on an isoscalar …

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Erratum to: Azimuthal asymmetries of charged hadrons produced in high-energy muon scattering off longitudinally polarised deuterons

C. Adolph, M. Aghasyan, R. Akhunzyanov, M. Alexeev et autres

The original version of this article unfortunately contained a mistake.

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Measurement of the cross section for hard exclusive $\pi^0$ muoproduction on the proton

G. D. Alexeev, Y. Kulinich, F. Kunne, K. Kurek et autres

We report on a measurement of hard exclusive $\pi^0$ muoproduction on the proton by COMPASS using 160 GeV/$c$ polarised $\mu^+$ and $\mu^-$ beams of the CERN SPS impinging on a liquid hydrogen target. From the average of the measured $\mu^+$ and $\mu^-$ …

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