Improved measurement of the longitudinal spin transfer to $\Lambda$ and $\bar{\Lambda }$ hyperons in polarized proton-proton collisions at $\sqrt{s}$ = 200 GeV

Abstract

The longitudinal spin transfer $D_{LL}$ to $\Lambda$ and $\bar{\Lambda }$ hyperons produced in high-energy polarized proton--proton collisions is expected to be sensitive to the helicity distribution functions of strange quarks and anti-quarks of the proton, and to longitudinally polarized fragmentation functions. We report an improved measurement of $D_{LL}$ from data obtained at a center-of-mass energy of $\sqrt{s}$ = 200 GeV with the STAR detector at RHIC. The data have an approximately twelve times larger figure-of-merit than prior results and cover $|\eta |<$ 1.2 in pseudo-rapidity with transverse momenta $p_T$ up to 6 GeV/c. In the forward scattering hemisphere at largest $p_T$, the longitudinal spin transfer is found to be $D_{LL}$ = -0.036 $\pm$ 0.048 (stat) $\pm$ 0.013(sys) for $\Lambda$ hyperons and $D_{LL}$ = 0.032 $\pm$ 0.043\,(stat) $\pm$ 0.013\,(sys) for $\bar{\Lambda }$ anti-hyperons. The dependences on $\eta$ and $p_T$ are presented and compared with model evaluations.

arXiv comment8 pages, 4 figures

References in corpus (28)

• PYTHIA 6.4 Physics and Manual
• PYTHIA 6.2 Physics and Manual
• Tuning Monte Carlo Generators: The Perugia Tunes
• Global $\Lambda$ hyperon polarization in nuclear collisions: evidence for the most vortical fluid
• The STAR Time Projection Chamber: A Unique Tool for Studying High Multiplicity Events at RHIC
• A first unbiased global determination of polarized PDFs and their uncertainties
• Measurements of Strange Particle Production in $p+p$ Collisions at $\sqrt{s}$= 200 GeV
• Evidence for polarization of gluons in the proton
• First simultaneous extraction of spin-dependent parton distributions and fragmentation functions from a global QCD analysis
• QCD Analysis of Unpolarized and Polarized Lambda - Baryon Production in Leading and Next-to-Leading Order
• Longitudinal double-spin asymmetry and cross section for inclusive jet production in polarized proton collisions at sqrt(s) = 200 GeV
• Measurement of the Neutrino Neutral-Current Elastic Differential Cross Section
• The nucleon spin and momentum decomposition using lattice QCD simulations
• Asymmetry of Lambda Baryons in Hadronic Z^0 Decays
• Up, down, and strange nucleon axial form factors from lattice QCD
• Polarized Lambda-Baryon Production in pp Collisions
• Spin content of Lambda and its longitudinal polarization in $e^{+}{e}^{-}$ annihilation at high energies
• Lambda and Antilambda polarization from deep inelastic muon scattering
• Measurement of the Longitudinal Spin Transfer to Lambda and Anti-Lambda Hyperons in Polarised Muon DIS
• The RHIC Cold QCD Plan for 2017 to 2023: A Portal to the EIC
• Measurement of the Antilambda Polarization in nu_mu Charged Current Interactions in the NOMAD Experiment
• Longitudinal Spin Transfer to the $\Lambda$ Hyperon in Semi-Inclusive Deep-Inelastic Scattering
• Spin structure and longitudinal polarization of hyperon in e+e- annihilation at high energies
• Longitudinal Spin Transfer to $\Lambda$ and $\bar{\Lambda }$ Hyperons in Polarized Proton-Proton Collisions at $\sqrt{s}$ = 200 GeV
• Anti-Lambda polarization in high energy pp collisions with polarized beam
• Transverse spin transfer to $\Lambda$ and $\bar{\Lambda }$ hyperons in polarized proton-proton collisions at $\sqrt{s}=200\mathrm{GeV}$
• Spin Transfers for Baryon Production in Polarized pp Collisions at RHIC-BNL
• Anti-Hyperon polarization in high energy pp collisions with polarized beams

Cited by in corpus (10)

• Polarized jet fragmentation functions
• The Spin Alignment of Vector Mesons in High Energy pp Collisions
• Several Topics on Transverse Momentum-Dependent Fragmentation Functions
• Longitudinal and transverse spin transfer to $\Lambda$ and $\overline{\Lambda }$ hyperons in polarized $p$+$p$ collisions at $\sqrt{s}=200$ GeV
• Deep Exclusive Meson Production as a probe to the puzzle of $\Lambda$ hyperon polarization
• Suppression of Spin Transfer to $\Lambda$ Hyperon in Deep-Inelastic Scattering
• Parton Fragmentation Functions
• Heavy quark polarization anisotropy as a novel probe of fireball geometry
• Longitudinal Spin Transfer to $\Lambda$ Hyperons in Semi-Inclusive Deep Inelastic Scattering with CLAS12
• Longitudinal and transverse spin transfer to $\Lambda$ and $\bar{\Lambda }$ hyperons in p+p collisions at STAR