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Browsing by Author "COMPASS collaboration (210 authors)"

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  • Hadron Transverse Momentum Distributions in Muon Deep Inelastic Scattering at 160 GeV/$c$
    Publication . COMPASS collaboration (210 authors); Bordalo, P.; Franco, C.; Nunes, A.S.; Quaresma, M.; Quintans, C.; Ramos, S.; Silva, L.; Stolarski, M.
    Multiplicities of charged hadrons produced in deep inelastic muon scattering off a (6)LiD target have been measured as a function of the DIS variables x ( )Bj( ), Q (2), W (2) and the final state hadron variables p ( )T( ) and z. The distributions are fitted with a single exponential function at low values of to determine the dependence of on x ( )Bj( ), Q (2), W (2) and z. The z-dependence of is shown to be a potential tool to extract the average intrinsic transverse momentum squared of partons, , as a function of x ( )Bj( ) and Q (2) in a leading order QCD parton model.
    2013-08-23Journal article Open access Show more
  • Longitudinal double spin asymmetries in single hadron quasi-real photoproduction at high $p_T$
    Publication . COMPASS collaboration (210 authors); Bordalo, P; Franco, C; Nunes, A S; Quaresma, M; Quintans, C; Ramos, S; Silva, L; Stolarski, M
    We measured the longitudinal double spin asymmetries $A_{LL}$ for single hadron muo-production off protons and deuterons at photon virtuality $Q^2$ < 1(GeV/$\it c$)$^2$ for transverse hadron momenta $p_T$ in the range 0.7 GeV/$\it c$ to 4 GeV/$\it c$ . They were determined using COMPASS data taken with a polarised muon beam of 160 GeV/$\it c$ or 200 GeV/$\it c$ impinging on polarised $\mathrm{{}^6LiD}$ or $\mathrm{NH_3}$ targets. The experimental asymmetries are compared to next-to-leading order pQCD calculations, and are sensitive to the gluon polarisation $\Delta G$ inside the nucleon in the range of the nucleon momentum fraction carried by gluons $0.05 < x_g < 0.2$.
    2016-02-10Journal article Open access Show more
  • Resonance Production and $\pi\pi$ S-wave in $\pi^- + p \rightarrow \pi^- \pi^- \pi^+ + p_{recoil}$ at 190 GeV$/c$
    Publication . COMPASS collaboration (210 authors); Bordalo, P; Franco, C; Nunes, A S; Quaresma, M; Quintans, C; Ramos, S; Silva, L; Stolarski, M
    The COMPASS collaboration has collected the currently largest data set on diffractively produced π-π-π+ final states using a negative pion beam of 190  GeV/c momentum impinging on a stationary proton target. This data set allows for a systematic partial-wave analysis in 100 bins of three-pion mass, 0.5
    2017-02-16Journal article Open access Show more