Transverse Polarization of $\Lambda$ Hyperons in Relativistic Au--Au Collisions at the AGS

2002 ◽  
Vol 15 (3-4) ◽  
pp. 437-444
Author(s):  
Rene Bellwied ◽  
E896 Collaboration
2000 ◽  
Vol 13 (3) ◽  
pp. 427-432 ◽  
Author(s):  
A.N. Aleev ◽  
V.P. Balandin ◽  
E.A. Dvalishvili ◽  
A.N. Gaponenko ◽  
A.V. Gusev ◽  
...  

2021 ◽  
Vol 81 (4) ◽  
Author(s):  
Hui Li ◽  
Xiaoyu Wang ◽  
Yongliang Yang ◽  
Zhun Lu

AbstractWe investigate the transverse polarization of the $$\Lambda $$ Λ hyperon in the processes $$e^+e^-\rightarrow \Lambda ^\uparrow \pi ^\pm X$$ e + e - → Λ ↑ π ± X and $$e^+e^-\rightarrow \Lambda ^\uparrow K^\pm X$$ e + e - → Λ ↑ K ± X within the framework of the transverse momentum dependent (TMD) factorization. The transverse polarization is contributed by the convolution of the transversely polarizing fragmentation function (PFF) $$D_{1T}^\perp $$ D 1 T ⊥ of the lambda hyperon and the unpolarized fragmentation function $$D_1$$ D 1 of pion/kaon. We adopt the spectator diquark model result for $$D_{1T}^{\perp }$$ D 1 T ⊥ to numerically estimate the transverse polarization in $$e^+e^-\rightarrow \Lambda ^\uparrow h X$$ e + e - → Λ ↑ h X process at the kinematical region of Belle Collaboration. To implement the TMD evolution formalism of the fragmentation functions, we apply two different parametrizations on the nonperturbative Sudakov form factors associated with the fragmentation functions of the $$\Lambda $$ Λ , pion and kaon. It is found that our prediction on the polarization in the $$\Lambda \pi ^+$$ Λ π + production and $${\bar{\Lambda }} \pi ^-$$ Λ ¯ π - is consistent with the recent Belle measurement in size and sign, while the model predictions on the polarizations in $$\Lambda \pi ^-$$ Λ π - and $$\Lambda K^\pm $$ Λ K ± productions show strong disagreement with the Belle data. The reason for the discrepancies is discussed and possible approaches to improve the calculation in the future are also discussed.


1997 ◽  
Vol 55 (9) ◽  
pp. 5334-5340 ◽  
Author(s):  
Marco Fabbrichesi ◽  
Francesco Vissani

1995 ◽  
Vol 51 (5) ◽  
pp. 2475-2477 ◽  
Author(s):  
W. Bernreuther ◽  
J. P. Ma ◽  
B. H. J. McKellar

Author(s):  
Wenhao Xia ◽  
Jie Gao ◽  
Yiwei Wang ◽  
Dou Wang

In this paper, we give preliminary designs of beam polarization manipulations by inserting three different types of insertions in the Circular Electron–Positron Collider (CEPC) at center-of-mass energies of 91 GeV (Z-pole). With the wigglers in the collider ring, we can obtain 5% transverse polarization in 1.1 h for the precise energy measurement. To overcome depolarization effects as the beam energy rises from 10 GeV to 45.5 GeV in the booster ring, Siberian snakes based on helical magnets are adopted. Finally, for longitudinally polarized beam collisions, a schematic design of spin rotators based on solenoids in the collider ring is studied.


1968 ◽  
Vol 174 (2) ◽  
pp. 460-462
Author(s):  
L. Braicovich ◽  
B. De Michelis ◽  
A. Fasana

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