Improved measurement of the longitudinal spin transfer to Lambda and (Lambda)over-bar hyperons in polarized proton-proton collisions at root s=200 GeV

0499362 - ÚJF 2019 RIV US eng J - Journal Article
Adam, J. - Adamczyk, L. - Adams, J. R. - Adkins, J. K. - Agakishiev, G. - Bielčík, J. - Bielčíková, Jana - Chaloupka, P. - Federič, Pavol - Federičová, P. - Harlenderová, A. - Holub, L. - Kvapil, J. - Kramárik, L. - Lidrych, J. - Matonoha, O. - Rusňák, Jan - Rusňáková, O. - Šimko, Miroslav - Šumbera, Michal - Vaněk, Jan … Total 353 authors
Improved measurement of the longitudinal spin transfer to Lambda and (Lambda)over-bar hyperons in polarized proton-proton collisions at root s=200 GeV.
Physical Review D. Roč. 98, č. 11 (2018), č. článku 112009. ISSN 2470-0010. E-ISSN 2470-0029
R&D Projects: GA MŠMT EF16_013/0001569
Institutional support: RVO:61389005
Keywords : STAR collaboration * proton-proton collisions * production
OECD category: Particles and field physics
Impact factor: 4.368, year: 2018

The longitudinal spin transfer D-LL to Lambda and (Lambda) over bar hyperons produced in high-energy polarized proton-proton collisions is expected to be sensitive to the helicity distribution functions of strange quarks and antiquarks 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 root 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 vertical bar eta vertical bar<1.2 in pseudorapidity 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 +/- 0.048 (stat) +/- 0.013 (sys) for Lambda hyperons and D-LL = 0.032 +/- 0.043 (stat) +/- 0.013(sys) for <(Lambda)over bar> antihyperons. The dependences on eta and p(T) are presented and compared with model evaluations.
Permanent Link: http://hdl.handle.net/11104/0291573