T. Rudnicki

Collins and Sivers transverse-spin asymmetries in inclusive muoproduction of ρ0 mesons

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

The production of vector mesons in deep inelastic scattering is an interesting yet scarcely explored channel to study the transverse spin structure of the nucleon and the spin-dependence of fragmentation. The COMPASS collaboration has performed the first measurement of the Collins and …

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

Double J/ψ production in pion-nucleon scattering at COMPASS

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

We present the study of the production of double J / ψ mesons using COMPASS data collected with a 190 GeV / c π − beam scattering off NH 3 , Al and W targets. Kinematic distributions of the collected double J …

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

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 …

ru, it, us, ch, cz, pl, pt, de, fr, tw, jp (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)

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 …