اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدMeasurement of the longitudinal spin asymmetries for weak boson production in proton-proton collisions at $sqrt{s}$ = 510 GeV
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We report new STAR measurements of the single-spin asymmetries $A_L$ for $W^+$ and $W^-$ bosons produced in polarized proton--proton collisions at $sqrt{s}$ = 510 GeV as a function of the decay-positron and decay-electron pseudorapidity. The data were obtained in 2013 and correspond to an integrated luminosity of 250 pb$^{-1}$. The results are combined with previous results obtained with 86 pb$^{-1}$. A comparison with theoretical expectations based on polarized lepton-nucleon deep-inelastic scattering and prior polarized proton--proton data suggests a difference between the $bar{u}$ and $bar{d}$ quark helicity distributions for $0.05 < x < 0.25$. In addition, we report new results for the double-spin asymmetries $A_{LL}$ for $W^pm$, as well as $A_L$ for $Z/gamma^*$ production and subsequent decay into electron--positron pairs.
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We report measurements of single- and double- spin asymmetries for $W^{pm}$ and $Z/gamma^*$ boson production in longitudinally polarized $p+p$ collisions at $sqrt{s} = 510$ GeV by the STAR experiment at RHIC. The asymmetries for $W^{pm}$ were measure
d as a function of the decay lepton pseudorapidity, which provides a theoretically clean probe of the protons polarized quark distributions at the scale of the $W$ mass. The results are compared to theoretical predictions, constrained by recent polarized deep inelastic scattering measurements, and show a preference for a sizable, positive up antiquark polarization in the range $0.05<x<0.2$.
Transverse single spin asymmetry, $A_{N}$, of very forward $pi^{0}$ production from polarized $p + p$ collisions provides new information toward an understanding of its production mechanism. $A_{N}$ of forward $pi^{0}$ in the pseudorapidity region of
$3 < eta < 4$ has been described by the partonic structure of the proton in the perturbative QCD framework. However, recent data indicates a potential contribution from not only partonic but also diffractive interactions. In order to provide a new insight on the origin of the $A_{N}$, we measured the very forward $pi^{0}$ production in the pseudorapidity region of $6 < eta$ from $sqrt{s}$ = 510 GeV polarized $p + p$ collisions at RHIC in 2017. We report our measurement of the very forward $pi^{0}$ over the transverse momentum range of $0 < p_{T} < 1$ GeV/$c$ and the preliminary result.
The PHENIX experiment has measured the spin alignment for inclusive $J/psirightarrow e^{+}e^{-}$ decays in $p$+$p$ collisions at $sqrt{s}=510$ GeV at midrapidity. The angular distributions have been measured in three different polarization frames, an
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We report a new high-precision measurement of the mid-rapidity inclusive jet longitudinal double-spin asymmetry, $A_{LL}$, in polarized $pp$ collisions at center-of-mass energy $sqrt{s}=200$ GeV. The STAR data place stringent constraints on polarized
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This contribution reports on a proof-of-principle measurement of the longitudinal spin transfer $D_{LL}$ in inclusive $Lambda$ and $bar Lambda$ production in polarized proton-proton collisions at a center of mass energy $sqrt{s}$ = 200 GeV. The data
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